JP7791018B2 - Dicing tape and method for manufacturing semiconductor device using dicing tape - Google Patents

Description

The present invention relates to a dicing tape that can be used in the manufacturing process of a semiconductor device and a method for manufacturing a semiconductor device using the dicing tape.

In the manufacture of semiconductor devices, dicing tape and dicing die bond films, which are dicing tape and die bond films integrated together, are used.

Dicing tape consists of a base film with an adhesive layer applied to it, and is used to hold and secure the individual semiconductor chips diced into the wafer during dicing to prevent them from scattering. The individual semiconductor chips are then peeled off the adhesive layer of the dicing tape and attached to a substrate such as a lead frame, wiring board, or another semiconductor chip using a separately prepared adhesive or adhesive film.

A dicing die bond film is a die bond film (hereinafter sometimes referred to as an "adhesive film" or "adhesive layer") removably disposed on the adhesive layer of a dicing tape. In the manufacture of semiconductor devices, a dicing die bond film is used to place and attach a semiconductor wafer, whether singulated or not, onto the die bond film to obtain individual semiconductor chips with the dicing die bond film. The semiconductor chip with the die bond film is then pushed up from the underside of the dicing tape using a push-up jig (e.g., a push-up pin), whereby it is peeled (picked up) together with the die bond film from the adhesive layer of the dicing tape and attached via the die bond film to an adherend such as a lead frame, wiring board, or another semiconductor chip.

The above-mentioned dicing die bond film is preferably used from the perspective of improving productivity, but in recent years, a method known as SDBG (Stealth Dicing Before Griding) has been proposed as a way to obtain semiconductor chips with die bond film using dicing die bond film, replacing the conventional full-cut cutting method using a high-speed rotating dicing blade, as it is said to be able to suppress chipping when thinning semiconductor wafers and dividing them into chips.

In this method, a semiconductor wafer is first attached to backgrinding tape, and laser light is irradiated into the interior of the semiconductor wafer along the planned dicing lines of the semiconductor wafer to selectively form modified regions at a predetermined depth from the surface of the semiconductor wafer without completely cutting the semiconductor wafer. The backgrinding is then performed to a predetermined thickness while appropriately adjusting the amount of grinding, and the backgrinding is singulated into multiple semiconductor chips on the backgrinding tape due to the grinding load of the grinding wheel. The multiple singulated semiconductor chips on the backgrinding tape are then attached to a dicing die bond film, transferred from the backgrinding tape to the dicing die bond film, and the dicing tape is expanded (hereinafter sometimes referred to as "cool expand") at low temperatures (e.g., -30°C to 0°C) to cleave the die bond film, which has been embrittled at low temperature, into the shape of each individual semiconductor chip. Finally, the die bond film is peeled off from the adhesive layer of the dicing tape by a pickup to obtain semiconductor chips with the die bond film attached.

In the above-mentioned pickup process, after the semiconductor wafer with die bond film is cleaved, the dicing tape is expanded at around room temperature (hereinafter sometimes referred to as "room temperature expansion") to widen the gap between adjacent individual semiconductor chips with die bond film (hereinafter sometimes referred to as "kerf width"). Any slack in the circumferential portion of the dicing tape outside the semiconductor chip holding area that occurs when the expanded state is released after expansion is removed by a heat shrinking (hereinafter sometimes referred to as "thermal contraction") process. By placing the dicing tape in a tensile state, the above-mentioned kerf width is maintained, and then the cleaved individual semiconductor chips with die bond film can be peeled off from the adhesive layer of the dicing tape and picked up.

Patent Document 1 discloses a dicing tape in which the adhesive layer contains an acrylic polymer, the acrylic polymer containing structural units of C9 to C11 alkyl (meth)acrylate and structural units of a hydroxyl group-containing (meth)acrylate, with the C9 to C11 alkyl (meth)acrylate structural units being 40 mol% to 85 mol%. The dicing tape in Patent Document 1 uses C9 to C11 alkyl (meth)acrylate to weaken the polarity of the acrylic polymer, reducing the affinity of the adhesive layer for the die bond film, and allowing the die bond film to be successfully peeled from the dicing tape even with a small amount of push-up during the pickup process.

Japanese Patent Application Laid-Open No. 2020-194879

In recent years, as semiconductor wafers have become thinner, chip cracking has become more likely to occur during wire bonding in the multi-layer semiconductor chip stacking process. To address this issue, wire-embedded die bond films that also function as spacers have been proposed. Wire-embedded die bond films require the wires to be embedded tightly during die bonding. Compared to conventional general-purpose die bond films used to secure semiconductor chips to lead frames or wiring substrates, wire-embedded die bond films tend to be thicker and more fluid (low melt viscosity at high temperatures). Therefore, when such wire-embedded die bond films are laminated on conventional dicing tape and used to manufacture semiconductor chips, the wire-embedded die bond film may not be cleanly cleaved along the dimensions of the individual semiconductor chips. One possible solution to this problem is to use a dicing tape with a substrate that experiences greater tensile stress at low temperatures than conventional dicing tape, allowing the cool-expanded dicing tape to apply a sufficient cleaving force (external stress) to the die bond film adhered to the dicing tape. However, this method presents the following new problems.

That is, in the above-mentioned cool expansion process, a cutting force (external stress) is applied from the cool-expanded dicing tape to the die bond film that is in close contact with the dicing tape. If the tensile stress of the dicing tape is sufficient at low temperatures, the die bond film will be cleanly cut along the size of the individual semiconductor chips, even if it is the above-mentioned difficult-to-cut wire-embedded die bond film. However, on the other hand, in addition to the impact when the die bond film is cut, stress in a direction away from the die bond film due to expansion immediately after cutting is also concentrated in the dicing tape portion between the semiconductor chips. This increases the distance between the semiconductor chips, and in the die bond film that corresponds to the size of the individual semiconductor chips, the edge portions (periphery on all four sides) of the die bond film may partially peel off from the adhesive layer of the dicing tape. The more layers of wiring circuits pre-formed on the surface of a semiconductor chip, the more likely the semiconductor chip is to warp, partly due to the difference in thermal expansion coefficient between the wiring circuits and the semiconductor chip material, which tends to promote partial peeling of the edge portions of the die bond film from the adhesive layer of the dicing tape.

When the adhesive layer of the dicing tape is composed of an adhesive composition curable with active energy rays (e.g., ultraviolet rays), the adhesive layer is cured by irradiating it with ultraviolet rays to reduce the adhesive strength of the adhesive layer before picking up the semiconductor chip with the die bond film from the dicing tape. However, as described above, if the edge portion of the die bond film of the semiconductor chip with the die bond film is peeled off from the adhesive layer of the dicing tape, the adhesive layer in the peeled portion comes into contact with oxygen in the air, and even when irradiated with ultraviolet rays, a reaction occurs between the growing polymer radical and oxygen, terminating the growth of the polymerization chain and inhibiting the polymerization of the active energy ray-curable adhesive composition, which may result in the adhesive layer not curing sufficiently. In such cases, the adhesive strength of the adhesive layer does not decrease sufficiently, and so during the pick-up process, when a pickup suction collet is brought into contact with and landed on the surface of a semiconductor chip with a die bond film on a dicing tape positioned on a push-up jig from above, the edge portion of the die bond film of the semiconductor chip with a die bond film that had peeled off from the adhesive layer of the dicing tape becomes strongly re-adhered to the adhesive layer that has not yet hardened due to ultraviolet irradiation, to the extent that the semiconductor chip with the die bond film cannot be easily peeled off from adhesive layer 2 even when the jig is pushed up from the underside of the dicing tape and sucked and lifted up by the suction collet, hindering pick-up of the semiconductor chip with a die bond film.

On the other hand, it is possible to eliminate the partial peeling by strengthening the adhesive strength of the adhesive layer to the die bond film, but in this case, the force required to peel the die bond film from the adhesive layer after UV irradiation during pick-up would also increase, and the pick-up properties would tend to decrease, so this is not a good idea.

In the above-mentioned pick-up process, when a jig is pushed up from the underside of the dicing tape to peel the die bond film of the semiconductor chip with the die bond film from the adhesive layer of the dicing tape after ultraviolet irradiation, peeling begins from the edge of the die bond film as the amount of pushing up of the jig increases, and then peeling progresses from the edge toward the center. However, the force required to peel the edge first, in other words, the force required to trigger peeling, is usually the greatest.

From this perspective, peeling of the edge portion of the die bond film already formed in the expanding step before the pick-up step may at first glance be considered advantageous for the progress of peeling in the pick-up step. However, as mentioned above, due to the poor curing caused by oxygen damage that is specific to adhesive layers composed of conventional active energy ray-curable adhesive compositions, when a pickup suction collet is brought into contact with and landed on the surface of a semiconductor chip with a die bond film on a dicing tape positioned on a push-up jig from above during the pick-up step, the edge portion of the die bond film of the semiconductor chip with a die bond film that had peeled off from the adhesive layer of the dicing tape becomes strongly re-adhered to the adhesive layer that has not been sufficiently cured by ultraviolet irradiation, to the extent that the semiconductor chip with a die bond film cannot be easily peeled from the adhesive layer 2 even by pushing up the jig from the underside of the dicing tape and by suction and lifting with the suction collet, which actually works against the grain.

If a pressure-sensitive adhesive layer composed of an active energy ray-curable pressure-sensitive adhesive composition that is far less susceptible to oxygen damage than pressure-sensitive adhesive layers composed of conventional active energy ray-curable pressure-sensitive adhesive compositions could be found, the effects of re-adhesion could be significantly reduced when intentionally forming peeling at the edge of the die bond film of a semiconductor chip with a die bond film from the pressure-sensitive adhesive layer during the expanding process prior to the pick-up process. In other words, the re-adhesion force could be weakened to a level where the semiconductor chip with the die bond film could be easily peeled from the pressure-sensitive adhesive layer 2 after UV irradiation by pushing up with a jig from the underside of the dicing tape and suction and lifting with a suction collet. This could potentially reduce the force required to peel the edge of the cleaved die bond film compared to conventional methods, resulting in good pick-up performance. However, currently, no dicing tape is available that uses a pressure-sensitive adhesive layer composed of an active energy ray-curable pressure-sensitive adhesive composition that is less susceptible to polymerization inhibition by oxygen. Therefore, there was room for research into the development of a dicing tape that makes it possible to take advantage of the peeling at the edge of the die bond film formed during this expanding process.

The present invention solves the above-mentioned problems of the prior art, and its objectives are to provide a dicing tape and dicing die bond film that (1) satisfactorily cleaves the die bond film by cool expanding, and leaves the edge portions (surrounding portions on all four sides) of the cleaved die bond film peeled from the adhesive layer of the dicing tape, and (2) significantly suppresses the phenomenon in which, during pick-up, the edge portions of the die bond film peeled from the adhesive layer re-adhere to the adhesive layer of the dicing tape after ultraviolet irradiation to the extent that they cannot be easily peeled off even when pushed up by a jig from the underside of the dicing tape or sucked and lifted by a suction collet, resulting in excellent pick-up properties for semiconductor chips with die bond film. Another objective is to provide a method for manufacturing a semiconductor device using this dicing tape.

The present invention provides
A dicing tape comprising a substrate film and a pressure-sensitive adhesive layer on the substrate film, the pressure-sensitive adhesive layer containing an active energy ray-curable pressure-sensitive adhesive composition,
When the elastic modulus of the base film at 5% elongation in the MD direction (the machine direction during film formation of the base film) at 0°C is defined as Y _MD and the elastic modulus of the base film at 5% elongation in the TD direction (the direction perpendicular to the MD direction) at 0°C is defined as Y _TD , the average value of the elastic moduli at 5% elongation (Y _MD +Y _TD )/2 is in the range of 165 MPa or more and 260 MPa or less,
The active energy ray-curable pressure-sensitive adhesive composition comprises an acrylic pressure-sensitive adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, a photopolymerization initiator, and a polyisocyanate-based crosslinking agent that undergoes a crosslinking reaction with the hydroxyl group;
the acrylic adhesive polymer has a hydroxyl value in the range of 12.0 mgKOH/g or more and 40.5 mgKOH/g or less , the polyisocyanate crosslinking agent is contained in an amount in the range of 2.4 parts by mass or more and 7.0 parts by mass or less relative to 100 parts by mass of the acrylic adhesive polymer, and an equivalent ratio (-NCO/-OH) of an isocyanate group (-NCO) of the polyisocyanate crosslinking agent to a hydroxyl group (-OH) of the acrylic adhesive polymer is adjusted in the range of 0.14 or more and 1.32 or less,
The adhesive layer of the dicing tape has an adhesive strength A (accumulated ultraviolet light intensity: 150 mJ/ ^m2 , peel angle: 90°, peel speed: 300 mm/min) of 3.50 N/25 mm or less after ultraviolet irradiation in the presence of oxygen to a stainless steel plate (SUS304 BA plate) at 23°C, and an adhesive strength B (accumulated ultraviolet light intensity: 150 mJ/ ^m2 , peel angle: 90°, peel speed: 300 mm/min) of 0.25 N/25 mm or more and 0.70 N/25 mm or less after ultraviolet irradiation in the absence of oxygen to a stainless steel plate (SUS304 BA plate) at 23°C.

In one embodiment, the substrate film is a resin film composed of a resin composition containing a thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and a polyamide resin (PA).

In one embodiment, the active energy ray-curable pressure-sensitive adhesive composition contains at least three types of photopolymerization initiators: (a) an α-aminoalkylphenone-based photopolymerization initiator, (b) an alkylphenone-based photopolymerization initiator other than an α-aminoalkylphenone-based photopolymerization initiator, and (c) an acylphosphine oxide-based photopolymerization initiator.

In one embodiment, the respective contents of the α-aminoalkylphenone photopolymerization initiator (a), the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and the acylphosphine oxide photopolymerization initiator (c) are, relative to 100 parts by mass of the acrylic adhesive polymer, such that the α-aminoalkylphenone photopolymerization initiator (a) is in the range of 0.8 parts by mass to 5.0 parts by mass, the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b) is in the range of 0.2 parts by mass to 5.0 parts by mass, and the acylphosphine oxide photopolymerization initiator (c) is in the range of 0.2 parts by mass to 2.0 parts by mass.

In one embodiment, the ratio A/B of the adhesive strength A after ultraviolet irradiation in the presence of oxygen to the adhesive strength B after ultraviolet irradiation in the absence of oxygen is in the range of 3.00 or more and 5.00 or less.

In one embodiment, the dicing tape is used to expand (stretch) a sheet-like laminate, in which a die bond film and multiple singulated semiconductor chips are sequentially laminated on the pressure-sensitive adhesive layer, at a temperature of -30°C to 0°C, and to cleave the die bond film to match the shape of the singulated semiconductor chips.

In one embodiment, the dicing tape is such that when the dicing tape to which the sheet-like laminate is attached is expanded at a temperature in the range of -30°C or higher and 0°C or lower, and the die bond film is cut to match the shape of the individual semiconductor chips, the edge portions (surrounding portions on all four sides) of the die bond film peel off from the adhesive layer.

In one embodiment, the die bond film that has been cut to match the shape of the individual semiconductor chip has an area ratio of the edge portions (surrounding portions on all four sides) of the die bond film that has been peeled off from the adhesive layer in the range of 10% to 45% of the total area of the cut die bond film.

The present invention also provides a method for manufacturing a semiconductor device using the dicing tape.

According to the present invention, (1) the die bond film is satisfactorily cleaved by cool expanding, and the edge portions (surrounding portions on all four sides) of the cleaved die bond film are peeled from the adhesive layer of the dicing tape; and (2) during pickup, the phenomenon in which the edge portions of the die bond film that have been peeled from the adhesive layer re-adhere strongly to the adhesive layer of the dicing tape after ultraviolet irradiation to the extent that they cannot be easily peeled off even when pushed up by a jig from the underside of the dicing tape or sucked and lifted by a suction collet is significantly suppressed, resulting in a dicing tape with excellent pickup properties. Also provided is a method for manufacturing a semiconductor device using this dicing tape.

1 is a cross-sectional view showing an example of the configuration of a base film of a dicing tape to which the present embodiment is applied. 1 is a cross-sectional view showing an example of the configuration of a dicing tape to which the present embodiment is applied. FIG. 1 is a cross-sectional view showing an example of a dicing die-bonding film having a configuration in which a dicing tape to which the present embodiment is applied is bonded to a die-bonding film. This is a schematic diagram showing a top view of an adhesive/coating peeling analysis device with a flexible peel angle for measuring the adhesive strength of dicing tape. 1 is a flowchart illustrating a method for manufacturing a dicing tape. 1 is a flowchart illustrating a method for manufacturing a semiconductor chip. FIG. 1 is a perspective view showing a state in which a ring frame (wafer ring) is attached to the outer edge of a dicing die bond film and a diced semiconductor wafer is attached to the center of the die bond film. 1A to 1F are cross-sectional views showing an example of a grinding process of a semiconductor wafer in which multiple modified regions have been formed by laser light irradiation, and a bonding process of multiple cleaved semiconductor wafers to a dicing die bond film. 10A to 10F are cross-sectional views showing an example of manufacturing a semiconductor chip using a plurality of cleaved thin-film semiconductor wafers to which a dicing die bond film is attached. FIG. 10 is an enlarged cross-sectional view showing an example of a state in which edge portions (four-sided periphery portions) of a cleaved die-bonding film are partially peeled off from the pressure-sensitive adhesive layer of the dicing tape. This is an enlarged plan view of the edge portion (four-sided surrounding portion) of the cleaved die bond film partially peeled off from the adhesive layer of the dicing tape, observed from the back surface side (base film side) of the semiconductor chip. FIG. 1 is a schematic cross-sectional view of one embodiment of a semiconductor device having a stacked structure using a semiconductor chip manufactured using a dicing die bond film in which a dicing tape to which this embodiment is applied is bonded to a die bond film. FIG. 10 is a schematic cross-sectional view of one aspect of another semiconductor device using a semiconductor chip manufactured using a dicing die bond film configured by bonding a dicing tape to which this embodiment is applied to the die bond film.

A preferred embodiment of the present invention will be described in detail below, with reference to the drawings as necessary. However, the present invention is not limited to the following embodiment.

<Configuration of dicing tape and dicing die bond film>
1A to 1D are cross-sectional views showing an example of the configuration of a substrate film 1 of a dicing tape to which this embodiment is applied. The substrate film 1 of the dicing tape of this embodiment may be a single layer of a single resin composition (see FIG. 1A (a) 1-A), a laminate consisting of multiple layers of the same resin composition (see FIG. 1B (b) 1-B), or a laminate consisting of multiple layers of different resin compositions (see FIG. 1C (c) 1-C and (d) 1-D). When a laminate consisting of multiple layers is used, the number of layers is not particularly limited, but is preferably in the range of 2 to 5 layers.

Fig. 2 is a cross-sectional view showing an example of the configuration of a dicing tape to which this embodiment is applied. As shown in Fig. 2, dicing tape 10 has a configuration in which pressure-sensitive adhesive layer 2 is provided on a first surface of base film 1. Although not shown, a releasable base sheet (release liner) may be provided on the surface of pressure-sensitive adhesive layer 2 of dicing tape 10 (the surface opposite to the surface facing base film 1). Base film 1 is composed of a resin film in which, when YMD is the elastic modulus at 5% elongation in the MD direction (the machine direction during film formation of the base film) at 0°C and _YTD is the elastic modulus at 5% elongation in the TD direction (the direction perpendicular to the MD direction) at 0° _C , the average value ( _YMD + _YTD )/2 of the elastic modulus at 5% elongation is in the range of 165 MPa or more and 260 MPa or less. The adhesive that forms the adhesive layer 2 may be, for example, an active energy ray-curable acrylic adhesive that hardens and shrinks when irradiated with active energy rays such as ultraviolet (UV) rays, thereby reducing its adhesive strength to the adherend.

Dicing tape 10 having such a configuration is used, for example, as follows in the semiconductor manufacturing process. Multiple individual semiconductor chips, obtained by backgrinding a semiconductor wafer with dividing grooves formed on its surface using a blade or a semiconductor wafer with a modified layer formed inside using a laser, are attached and held (temporarily fixed) on the adhesive layer 2 of the dicing tape 10 via a die bond film (adhesive layer). The die bond film is then cleaved according to the shape of each individual semiconductor chip using cool expansion, after which the kerf width between the semiconductor chips is sufficiently expanded using room temperature expansion and heat shrink processes. The individual semiconductor chips with the die bond film attached are then peeled from the adhesive layer 2 of the dicing tape 10 in a pick-up process. The resulting semiconductor chips with the die bond film attached are then fixed to an adherend such as a lead frame, wiring board, or another semiconductor chip.

Figure 3 is a cross-sectional view showing an example of a configuration in which a dicing tape 10 to which this embodiment is applied is bonded and integrated with a die bond film (adhesive film) 3, a so-called dicing die bond film. As shown in Figure 3, the dicing die bond film 20 has a configuration in which the die bond film (adhesive film) 3 is releasably adhered and laminated onto the pressure-sensitive adhesive layer 2 of the dicing tape 10.

A dicing die bond film 20 having such a configuration is used, for example, as follows in the semiconductor manufacturing process. Multiple individual semiconductor chips, obtained by backgrinding a semiconductor wafer with dividing grooves formed on its surface using a blade or a semiconductor wafer with a modified layer formed internally using a laser, are attached and held (adhered) to the die bond film 3 of the dicing die bond film 20. The die bond film 3, which has been embrittled at low temperature, is then cut according to the shape of each individual semiconductor chip to obtain individual semiconductor chips with the die bond film. Next, the kerf width between the semiconductor chips with the die bond film is sufficiently expanded by room temperature expansion and heat shrinking processes, and the individual semiconductor chips with the die bond film are then peeled from the adhesive layer 2 of the dicing tape 10 by a pick-up process. The resulting semiconductor chips with the die bond film (adhesive film) 3 are then fixed to an adherend, such as a lead frame, wiring board, or another semiconductor chip, via the die bond film (adhesive film) 3. Although not shown, the surface of the adhesive layer 2 of the dicing tape 10 (the surface opposite to the surface facing the base film 1) and the surface of the die bond film 3 (the surface opposite to the surface facing the adhesive layer 2) may each be provided with a base sheet (release liner) having releasability, which may be peeled off as appropriate before use.

<Dicing tape>
(Base film)
The base film 1, which is the first constituent element of the dicing tape 10 of the present invention, will be described below.

[Elastic modulus of base film at 5% elongation at 0°C]
The base film 1 is a resin film having an average value (Y _MD +Y TD )/2 of the elastic moduli at 5% elongation at 0° C. in the MD direction (the machine direction during film formation of the base film) as Y MD and an average value (Y _{MD +Y TD )/2 of the elastic moduli at 5% elongation at 0° C. in the TD direction (the direction perpendicular to the MD direction) as Y TD in the base film 1. The average value (Y MD + Y TD} )/2 of the elastic moduli at 5% elongation at 0° C. of the base _film 1 is preferably in the range of 190 MPa or more and 240 MPa or less.

When the average value (Y _MD + Y _TD )/2 of the elastic modulus at 5% elongation at 0°C of the base film 1 is less than 165 MPa, even when the dicing tape 10 is expanded, stress in a direction away from the cleaved die bond film is less likely to act, and therefore, in the cleaved die bond film, a state in which it is partially peeled from the pressure-sensitive adhesive layer 2 of the dicing tape 10 may not be formed at its edge portion (four-sided peripheral portion). Furthermore, even if external stress is applied to the dicing tape 10 by expanding at low temperatures, the stress is not sufficiently transmitted to the die bond film 3, and therefore, particularly when a wire-embedded die bond film is used, the die bond film 3 may not be satisfactorily cleaved in the cool expanding step. Furthermore, when the value of (Y _MD + Y _TD )/2 is excessively small, the dicing tape 10 becomes soft and may be difficult to handle, or the kerf width may not be sufficiently secured. As a result, the effect of improving pickup property compared to conventional methods is not seen, or the pickup property is reduced.

On the other hand, when the average value (Y _MD + Y _TD )/2 of the elastic modulus at 5% elongation at 0° C. of the base film 1 exceeds 260 MPa, it may be difficult to expand the dicing tape 10. Even if expansion is possible, the die bond film 3 may peel excessively from the pressure-sensitive adhesive layer 2 during expansion, and sufficient external stress may not be applied substantially uniformly throughout the die bond film 3 via the pressure-sensitive adhesive layer 2, which may result in the die bond film 3 not being cleaved cleanly, or the kerf width not being sufficiently secured, or the kerf width being variable. Furthermore, when the excessively peeled die bond film re-adheres to the pressure-sensitive adhesive layer 2 in the pick-up step, the re-adhering area becomes excessively large. Therefore, even if the pressure-sensitive adhesive layer 2 is made of an active energy ray-curable pressure-sensitive adhesive composition that satisfies the requirements of the present invention, a large amount of energy corresponding to the large re-adhering area may be required to peel the dicing tape 10 by pushing it up with a jig from the underside thereof. As a result, the pick-up property of the semiconductor chip with the die bond film is reduced.

When the average value (Y _MD +Y _TD )/2 of the elastic modulus at 5% elongation at 0°C of the above-mentioned base film 1 is in the range of 165 MPa or more and 260 MPa or less, the dicing tape 10 can apply to the die bond film 3, in the cool expanding step, an external stress sufficient to cleave the die bond film 3 that is adhered to the pressure-sensitive adhesive layer 2 containing a specific active energy ray-curable pressure-sensitive adhesive composition described later, and can apply to the pressure-sensitive adhesive layer 2 of the dicing tape 10 a stress in a direction away from the die bond film 3 that is necessary to intentionally form an appropriate peel state between the edge portion of the cleaved die bond film and the pressure-sensitive adhesive layer 2. Furthermore, in this case, since the stress applied to the above-mentioned die bond film 3 and the pressure-sensitive adhesive layer 2 is appropriately suppressed, the cleaved die bond film does not peel excessively from the pressure-sensitive adhesive layer 2, a sufficient kerf width can be secured, and damage due to collision between semiconductor chips and displacement from their fixed positions on the pressure-sensitive adhesive layer 2, etc. can also be avoided. In this case, if the pressure-sensitive adhesive layer 2 is made of an active energy ray-curable pressure-sensitive adhesive composition that satisfies the requirements of the present invention, the pick-up property of the semiconductor chip with the die-bonding film can be made better than before.

The elastic modulus _YMD at 5% elongation in the MD direction and the elastic modulus _YTD at 5% elongation in the TD direction of the substrate film 1 in the present invention at 0° C. are measured by the following method. Specifically, first, test pieces having a length of 100 mm (MD direction) and a width of 10 mm (TD direction) were prepared as samples for measurement in the MD direction (number of samples N=5), and test pieces having a length of 100 mm (TD direction) and a width of 10 mm (MD direction) were prepared as samples for measurement in the TD direction (number of samples N=5). Next, using a tension/compression testing machine (model: MinebeaTechnoGraph TG-5kN) manufactured by MinebeaMitsumi Inc., both ends of the test piece in the longitudinal direction were fixed with chucks so that the initial distance between the chucks was 20 mm, and the test piece was placed in a thermostatic chamber (model: THB-A13-038) manufactured by MinebeaMitsumi Inc. at 0°C for 1 minute, after which a tensile test was performed at a rate of 100 mm/min to obtain a tensile load-elongation curve. Then, from the obtained tensile load-elongation curve, the slope of the line connecting the origin (starting point of elongation) and the point on the curve corresponding to the tensile load value (unit: N) when elongated 1.0 mm from the origin (5% elongation relative to the initial distance between the chucks of 20 mm) was calculated, and the slope was calculated using the following formula:

5% elongation modulus Y (unit: MPa) = (slope) x [(initial distance between chucks) / (cross-sectional area of test specimen)]

The elastic modulus Y of the base film 1 at 5% elongation is calculated from the above.
Measurements are made for N=5 samples in each direction, and the average values are designated as the elastic modulus at 5% elongation in the MD direction _YMD and the elastic modulus at 5% elongation in the TD direction _YTD . The average value of the elastic modulus at 5% elongation of the base film 1 at 0°C ( _YMD + _YTD )/2 in the present invention is a value calculated using the above respective values.

[Resin composition constituting the base film]
The resin composition constituting the substrate film 1 is not particularly limited as long as the average value of the elastic modulus at 5% elongation at 0°C (Y _MD + Y _TD )/2 of the substrate film 1 is within the above range, but from the viewpoint of achieving both expandability and heat shrinkability, it is preferably a resin composition containing a thermoplastic crosslinked resin. Specific examples of such resin compositions include a resin composition containing a thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer (hereinafter sometimes simply referred to as "ionomer"), and a resin composition containing a thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and a polyamide resin (PA). Resin films formed using these resin compositions can be suitably used as the substrate film 1. Among these resin compositions, since dicing tape 10 using the above-mentioned base film must be particularly compatible with the application of wire-embedded die-bonding films, a resin composition containing a thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer (hereinafter sometimes simply referred to as "ionomer") and a polyamide resin (PA) is preferred, as this makes it possible to provide a dicing tape 10 with an excellent balance of both low-temperature expandability and heat shrinkability.

The total amount of the thermoplastic crosslinked resin (IO) composed of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA) in the entire base film 1 is not particularly limited as long as the average value of the elastic modulus at 5% elongation at 0°C of the base film 1 (Y _MD +Y _TD )/2 is within the above range, but it is preferably 65% by mass or more and 100% by mass or less of the total amount of the resin composition constituting the entire base film 1, more preferably 75% by mass or more and 100% by mass or less, and particularly preferably 85% by mass or more and 100% by mass or less.

Dicing tape 10 using a substrate film 1 of this configuration, with the die bond film 3 adhered to its adhesive layer 2, can be stretched at low temperatures to apply an appropriate cleaving force (external stress) to the die bond film 3, making it suitable for use in the cool expansion process and even the room temperature expansion process in the manufacturing process of semiconductor devices. That is, the cool expansion process effectively cleaves the die bond film 3 according to the individual shapes of the individual semiconductor chips that have already been singulated, making it suitable for obtaining individual semiconductor chips with die bond films of a predetermined size with a high yield. Furthermore, the cool expansion of dicing tape 10, which follows immediately after cleaving the die bond film 3, can also apply an appropriate stress to the adhesive layer 2 of dicing tape 10 in a direction away from the individual cleaved die bond films. This makes it suitable for appropriately and intentionally creating a state in which the edges (four-sided periphery) of each cleaved die bond film are partially peeled from the adhesive layer 2 of dicing tape 10. Furthermore, even during the room temperature expansion process, the expandability necessary to ensure sufficient kerf width between semiconductor chips is maintained.

[Resin composition containing thermoplastic crosslinked resin (IO) composed of ionomer of ethylene-unsaturated carboxylic acid copolymer and polyamide resin (PA)]
As described above, a resin film composed of a resin composition containing a thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and a polyamide resin (PA) is a preferred embodiment of the substrate film 1 in the present invention. The thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA) will be described below.

[Thermoplastic crosslinked resin (IO) composed of an ionomer of an ethylene-unsaturated carboxylic acid copolymer]
In the base film 1 of the present embodiment, the thermoplastic crosslinked resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer is a resin in which some or all of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer have been neutralized (crosslinked) with metals (ions). In the following description, the "thermoplastic crosslinked resin made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer" may be referred to as a "resin made of an ionomer" or simply as an "ionomer."

The ethylene-unsaturated carboxylic acid copolymer constituting the ionomer is at least a binary copolymer in which ethylene and an unsaturated carboxylic acid are copolymerized, and may also be a ternary or higher multi-component copolymer in which a third copolymerization component is further copolymerized. The ethylene-unsaturated carboxylic acid copolymer may be used alone, or two or more types of ethylene-unsaturated carboxylic acid copolymers may be used in combination.

Examples of the unsaturated carboxylic acid constituting the ethylene-unsaturated carboxylic acid binary copolymer include unsaturated carboxylic acids having 4 to 8 carbon atoms, such as acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, maleic acid, and maleic anhydride. Acrylic acid and methacrylic acid are particularly preferred.

When the ethylene-unsaturated carboxylic acid copolymer is a ternary or higher multi-component copolymer, it may contain a third copolymer component to form the multi-component copolymer in addition to the ethylene and unsaturated carboxylic acid that constitute the binary copolymer. Examples of the third copolymer component include unsaturated carboxylic acid esters (e.g., (meth)acrylic acid alkyl esters having 1 to 12 carbon atoms in the alkyl moiety, such as methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, dimethyl maleate, and diethyl maleate), unsaturated hydrocarbons (e.g., propylene, butene, 1,3-butadiene, pentene, 1,3-pentadiene, and 1-hexene), vinyl esters (e.g., vinyl acetate and vinyl propionate), oxides such as vinyl sulfate and vinyl nitrate, halogen compounds (e.g., vinyl chloride and vinyl fluoride), vinyl-group-containing primary and secondary amine compounds, carbon monoxide, and sulfur dioxide. Among these copolymer components, unsaturated carboxylic acid esters are preferred.

The ethylene-unsaturated carboxylic acid copolymer may be in the form of a block copolymer, random copolymer, or graft copolymer, or may be in the form of a binary copolymer or tertiary copolymer. Among these, from the viewpoint of industrial availability, binary random copolymers, ternary random copolymers, graft copolymers of binary random copolymers, and graft copolymers of ternary random copolymers are preferred, with binary random copolymers and ternary random copolymers being more preferred. From the viewpoint of expandability, ternary random copolymers, which are less prone to necking during expansion, are particularly preferred.

Specific examples of the ethylene-unsaturated carboxylic acid copolymer include binary copolymers such as ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer, and terpolymers such as ethylene-methacrylic acid-2-methyl-propyl acrylate copolymer. Commercially available ethylene-unsaturated carboxylic acid copolymers may also be used, such as the Nucrel series (registered trademark) manufactured by DuPont-Mitsui Polychemicals.

The copolymerization ratio (mass ratio) of the unsaturated carboxylic acid ester in the above-mentioned ethylene-unsaturated carboxylic acid copolymer is preferably in the range of 1% by mass or more and 20% by mass or less, and from the viewpoints of expandability in the expanding process and heat resistance (blocking, fusion), it is more preferably in the range of 5% by mass or more and 15% by mass or less.

In the base film 1 of this embodiment, the ionomer used as the resin (IO) is preferably one in which the carboxyl groups contained in the ethylene-unsaturated carboxylic acid copolymer have been crosslinked (neutralized) with metal ions at an arbitrary ratio. Metal ions used to neutralize the acid groups include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, zinc ions, magnesium ions, and manganese ions. Among these metal ions, magnesium ions, and zinc ions are preferred due to the ease of availability of industrially produced products, with sodium ions and zinc ions being more preferred.

The degree of neutralization of the ethylene-unsaturated carboxylic acid copolymer in the ionomer is preferably in the range of 20 mol% to 85 mol%, more preferably in the range of 50 mol% to 82 mol%, and particularly preferably in the range of 65 mol% to 80 mol%. A neutralization degree of 20 mol% or more can further improve the cleavability of the die bond film 3 and can also improve the heat shrinkability of the dicing tape 10 in the heat shrink process described below. A neutralization degree of 85 mol% or less can further improve the film formability. The neutralization degree refers to the ratio (mol%) of metal ions to the number of moles of acid groups, particularly carboxyl groups, contained in the ethylene-unsaturated carboxylic acid copolymer.

The resin (IO) made from the ionomer has a melting point of approximately 85 to 100°C, and the melt flow rate (MFR) of the resin (IO) made from the ionomer is preferably in the range of 0.2 g/10 min to 20.0 g/10 min, more preferably in the range of 0.5 g/10 min to 20.0 g/10 min, and even more preferably in the range of 0.5 g/10 min to 18.0 g/10 min. A melt flow rate within the above range ensures good film-forming properties for the substrate film 1. The MFR is a value measured at 190°C and a load of 2160 g according to a method in accordance with JIS K7210-1999.

The resin composition constituting the base film 1 of the present embodiment preferably contains a polyamide resin (PA) in addition to the resin (IO) composed of the ionomer of an ethylene-unsaturated carboxylic acid copolymer described above. The mass ratio (IO):(PA) of the resin (IO) composed of the ionomer of an ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA) is preferably in the range of 72:28 to 95:5. By constructing the base film 1 using a resin composition mixed to achieve this mass ratio, it becomes easy to adjust the average elastic modulus at 5% elongation at 0°C of the base film 1 (Y _MD +Y _TD )/2 to fall within the above-mentioned range. The mass ratio (IO):(PA) is more preferably in the range of 74:26 to 92:8, and even more preferably in the range of 80:20 to 90:10. The upper and lower limits of the numerical ranges in this specification can be arbitrarily selected and combined.

[Polyamide resin (PA)]
Examples of the polyamide resin (PA) include polycondensates of carboxylic acids such as oxalic acid, adipic acid, sebacic acid, dodecanoic acid, terephthalic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid with diamines such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, decamethylenediamine, 1,4-cyclohexyldiamine, and m-xylylenediamine; ring-opening polymers of cyclic lactams such as ε-caprolactam and ω-laurolactam; polycondensates of aminocarboxylic acids such as 6-aminocaproic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid; and copolymers of the above-mentioned cyclic lactams, dicarboxylic acids, and diamines.

Commercially available polyamide resins (PA) can also be used. Specific examples include nylon 4 (melting point 268°C), nylon 6 (melting point 225°C), nylon 46 (melting point 240°C), nylon 66 (melting point 265°C), nylon 610 (melting point 222°C), nylon 612 (melting point 215°C), nylon 6T (melting point 260°C), nylon 11 (melting point 185°C), nylon 12 (melting point 175°C), nylon copolymers (e.g., nylon 6/66, nylon 6/12, nylon 6/610, nylon 66/12, nylon 6/66/610, etc.), nylon MXD6 (melting point 237°C), and nylon 46. Among these polyamides, nylon 6 and nylon 6/12 are preferred from the standpoint of film-forming properties and mechanical properties of the substrate film 1.

As described above, the content of the polyamide resin (PA) is preferably an amount such that the mass ratio (IO):(PA) of the resin (IO) composed of the ionomer of the ethylene-unsaturated carboxylic acid copolymer to the polyamide resin (PA) in the entire base film 1 is in the range of 72:28 to 95:5. If the mass ratio of the polyamide resin (PA) is below this range, particularly if the degree of neutralization by metal ions of the ionomer of the ethylene-unsaturated carboxylic acid copolymer is low, the effect of increasing the Young's modulus of the base film 1 (dicing tape 10) at low temperatures will be insufficient, and an appropriate cutting force (external stress) will not be applied to the die bond film 3 even when stretched at low temperatures, which may prevent the die bond film 3 from being cleanly cut. Furthermore, even if the base film 1 (dicing tape 10) is expanded, stress in a direction away from the cleaved die bond film is less likely to act, so there is a risk that the edge portions (surrounding portions on all four sides) of the cleaved die bond film will not be partially peeled from the pressure-sensitive adhesive layer 2 of the dicing tape 10.

On the other hand, if the mass ratio of the polyamide resin (PA) exceeds the above range, stable film formation may be difficult depending on the resin composition of the base film 1. Furthermore, the elastic modulus of the base film 1 at 5% elongation at low temperatures may increase excessively, making it difficult to expand the dicing tape 10. Even if expansion is possible, the die bond film 3 may peel excessively from the pressure-sensitive adhesive layer 2 during expansion, preventing sufficient external stress from being applied to the die bond film 3 via the pressure-sensitive adhesive layer 2, resulting in the risk of not being able to cleanly cleave the die bond film 3, or of not being able to ensure a sufficient kerf width, or of the kerf width varying. Furthermore, the flexibility of the base film 1 may be impaired, preventing the dicing tape 10 from maintaining its expandability in the room-temperature expanding step, or of causing pickup defects due to cracks or the like when picking up a semiconductor chip with a die bond film. The content of the polyamide resin (PA) is more preferably an amount such that the mass ratio (IO):(PA) of the resin (IO) composed of an ionomer of the ethylene-unsaturated carboxylic acid copolymer to the polyamide resin (PA) in the entire base film 1 is in the range of 74:26 to 92:8, and even more preferably an amount such that the mass ratio is in the range of 80:20 to 90:10.

When the base film 1 is a laminate consisting of multiple layers, the mass ratio of the resin (IO) made of the ionomer of the ethylene-unsaturated carboxylic acid copolymer to the polyamide resin (PA) refers to the value for the entire base film 1 (laminate) calculated from the mass ratio of the resin (IO) made of the ionomer of the ethylene-unsaturated carboxylic acid copolymer to the polyamide resin (PA) in each layer and the mass ratio of each layer in the entire base film 1 (laminate).

When the mass ratio of the resin (IO) composed of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA) in the entire base film 1 is within the above range, it becomes easy to adjust the average value of the elastic modulus at 5% elongation at 0° C. of the base film 1 (Y _MD +Y _TD )/2 to a range of 165 MPa or more and 260 MPa or less. As a result, in the cool expanding step, the dicing tape 10 can apply to the die bond film 3 an external stress sufficient to cleave the die bond film 3 adhered to the pressure-sensitive adhesive layer 2 containing a specific active energy ray-curable pressure-sensitive adhesive composition described later, and can also apply to the pressure-sensitive adhesive layer 2 of the dicing tape 10 a stress in a direction away from the die bond film 3 that is necessary to form an appropriate peel state between the edge portion of the cleaved die bond film and the pressure-sensitive adhesive layer 2. Furthermore, in this case, the stress applied to the die bond film 3 and the pressure-sensitive adhesive layer 2 is appropriately suppressed, so the cleaved die bond film does not peel excessively from the pressure-sensitive adhesive layer 2, and a sufficient kerf width can be ensured, which can also prevent damage due to collisions between semiconductor chips and displacement from fixed positions on the pressure-sensitive adhesive layer 2. In this case, if the pressure-sensitive adhesive layer 2 is composed of an active energy ray-curable pressure-sensitive adhesive composition that satisfies the requirements of the present invention, the pickup properties of the semiconductor chip with the die bond film can be made better than before.

〔others〕
The resin composition constituting the substrate film 1 may contain other resins or various additives as needed, provided that the effects of the present invention are not impaired. Examples of such other resins include polyolefins such as polyethylene and polypropylene, ethylene-unsaturated carboxylic acid copolymers, and polyetheresteramides. Such other resins can be blended in an amount of, for example, 20 parts by mass per 100 parts by mass of the resin (IO) made of the ionomer of the ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA). Examples of such additives include antistatic agents, antioxidants, heat stabilizers, light stabilizers, UV absorbers, pigments, dyes, lubricants, antiblocking agents, antifungal agents, antibacterial agents, flame retardants, flame retardant assistants, crosslinking agents, crosslinking assistants, foaming agents, foaming assistants, inorganic fillers, and fiber reinforcements. These various additives can be blended in an amount of, for example, 5 parts by mass per 100 parts by mass of the resin (IO) made of the ionomer of the ethylene-unsaturated carboxylic acid copolymer and the polyamide resin (PA).

[Thickness of base film]
The thickness of the base film 1 is not particularly limited, but considering its use as a dicing tape 10, it is preferably, for example, in the range of 70 μm to 120 μm. It is more preferably in the range of 70 μm to 110 μm. If the thickness of the base film 1 is less than 70 μm, there is a risk that the ring frame (wafer ring) will not be held sufficiently when the dicing tape 10 is subjected to a dicing process. Furthermore, if the thickness of the base film 1 is greater than 120 μm, there is a risk that the base film 1 will warp significantly due to the release of residual stress during film formation.

[Layer structure of base film]
The layer structure of the substrate film 1 is not particularly limited, and may be a single layer of a single resin composition, a laminate of multiple layers of the same resin composition, or a laminate of multiple layers of different resin compositions. When a laminate is made of multiple layers, the number of layers is not particularly limited, but is preferably in the range of 2 to 5 layers.

When the substrate film 1 is a laminate consisting of multiple layers, it may have a configuration in which multiple layers formed using the resin composition of this embodiment are laminated together, or it may have a configuration in which a layer formed using the resin composition of this embodiment is laminated onto a layer formed using a resin composition other than the resin composition of this embodiment.

Examples of layers formed using the other resin compositions include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), ethylene-α-olefin copolymer, polypropylene, ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid alkyl ester terpolymer, ethylene-unsaturated carboxylic acid alkyl ester copolymer, ethylene-vinyl ester copolymer, ethylene-unsaturated carboxylic acid alkyl ester-carbon monoxide copolymer, or unsaturated carboxylic acid grafted products thereof, either alone or in combination, and ionomers (IO) of the ethylene-unsaturated carboxylic acid copolymer. Among these, from the viewpoints of adhesion to the resin layer formed from a mixture of the resin (IO) composed of the ionomer of the ethylene-unsaturated carboxylic acid copolymer of the present embodiment and polyamide resin (PA), ethylene-unsaturated carboxylic acid copolymer, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid alkyl ester terpolymer, ethylene-unsaturated carboxylic acid alkyl ester copolymer, ionomers of these copolymers, ethylene-α-olefin copolymer, etc. are preferred.

Specific examples of substrate film 1 in this embodiment having a laminated structure include substrate films with the following two-layer and three-layer structures.

As a two-layer structure, for example,
(1) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)]/[A second resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(2) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)]/[A second resin layer made of a mixture of a resin (IO2) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA2)],
(3) [A first resin layer made of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer]/[A second resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(4) [First resin layer made of ethylene-unsaturated carboxylic acid copolymer]/[Second resin layer made of a mixture of resin (IO1) made of ionomer of ethylene-unsaturated carboxylic acid copolymer of the present embodiment and polyamide resin (PA1)],
Examples of such a resin include a two-layer structure ([first resin layer]/[second resin layer]) made of the same resin layer or different resin layers.

As a three-layer structure, for example,
(5) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A second resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A third resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(6) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A second resin layer made of a mixture of a resin (IO2) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA2)] / [A third resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(7) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A second resin layer made of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment] / [A third resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(8) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A second resin layer made of an ethylene-unsaturated carboxylic acid copolymer] / [A third resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
(9) [A first resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)] / [A second resin layer made of an ethylene-α-olefin copolymer] / [A third resin layer made of a mixture of a resin (IO1) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer of the present embodiment and a polyamide resin (PA1)],
and a three-layer structure ([first resin layer]/[second resin layer]/[third resin layer]) consisting of layers of the same resin or different resins such as those mentioned above.

[Method for producing substrate film]
Conventional methods can be used to form the substrate film 1 of this embodiment. A resin composition prepared by melt-kneading an ionomer resin (IO) and a polyamide resin (PA), optionally with other components, can be processed into a film by various molding methods, such as T-die casting, T-die nip molding, inflation molding, extrusion lamination, and calendar molding. Furthermore, when the substrate film 1 is a laminate consisting of multiple layers, each layer can be separately formed by calendar molding, extrusion, inflation molding, or the like, and then laminated by thermal lamination or by bonding with an appropriate adhesive to produce a laminate. Examples of the adhesive include the aforementioned various ethylene copolymers, or blends of any of a plurality of these ethylene copolymers, selected from the unsaturated carboxylic acid grafted products thereof. Alternatively, a laminate can be produced by simultaneously extruding the resin compositions of each layer using a coextrusion lamination method. The surface of the substrate film 1 that contacts the pressure-sensitive adhesive layer 2 may be subjected to corona treatment, plasma treatment, or the like to improve adhesion to the pressure-sensitive adhesive layer 2, as described below. In addition, the surface of the base film 1 opposite to the surface that comes into contact with the pressure-sensitive adhesive layer 2 may be subjected to an embossing treatment using a shiborol or the like for the purpose of stabilizing the winding of the base film 1 during film formation and preventing blocking after film formation.

(Adhesive layer)
The pressure-sensitive adhesive layer 2 containing an active energy ray-curable pressure-sensitive adhesive composition, which is the second constituent element of the dicing tape 10 of the present invention, will be described below.

As described above, the pressure-sensitive adhesive layer 2 comprises an active energy ray-curable pressure-sensitive adhesive composition containing an acrylic pressure-sensitive adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, a photopolymerization initiator, and a polyisocyanate-based crosslinking agent that crosslinks with the hydroxyl group. The active energy ray-curable pressure-sensitive adhesive composition contains 2.4 to 7.0 parts by mass of a polyisocyanate-based crosslinking agent per 100 parts by mass of an acrylic pressure-sensitive adhesive polymer having a hydroxyl value in the range of 12.0 to 40.5 mgKOH/g, and the equivalent ratio (-NCO/-OH) of the isocyanate groups (-NCO) of the polyisocyanate-based crosslinking agent to the hydroxyl groups (-OH) of the acrylic pressure-sensitive adhesive polymer is adjusted to be 0.14 to 1.32. The pressure-sensitive adhesive layer 2 of the dicing tape 10 has an adhesive strength of A after ultraviolet irradiation in the presence of oxygen to a stainless steel plate (SUS304 BA plate) in the range of 3.50 N/25 mm or less at 23°C, and an adhesive strength of B after ultraviolet irradiation in the absence of oxygen to a stainless steel plate (SUS304 BA plate) in the range of 0.25 N/25 mm to 0.70 N/25 mm.

[Acrylic adhesive polymer]
The acrylic adhesive polymer contained as a main component in the active energy ray-curable pressure-sensitive adhesive composition is an acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, and has a hydroxyl value in the range of 12.0 mgKOH/g to 40.5 mgKOH/g. The acrylic adhesive polymer preferably accounts for 90% by mass to 100% by mass, more preferably 95% by mass to 100% by mass, of the total mass of the active energy ray-curable pressure-sensitive adhesive composition.

The above-mentioned acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group is described in detail below, but is typically obtained by copolymerizing a (meth)acrylic acid alkyl ester monomer with a hydroxyl group-containing monomer as a base polymer to obtain a copolymer (acrylic adhesive polymer having a hydroxyl group), and then adding a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound) that can undergo an addition reaction with the hydroxyl groups in the copolymer.

As described above, the main chain (main skeleton) of the acrylic adhesive polymer having hydroxyl groups is composed of a copolymer containing at least a (meth)acrylic acid alkyl ester monomer and a hydroxyl group-containing monomer as copolymer components. The glass transition temperature (Tg) of the main chain of the acrylic adhesive polymer having hydroxyl groups is not particularly limited, but is preferably in the range of -65°C or higher and -45°C or lower. Here, the glass transition temperature (Tg) is a theoretical value calculated using Fox's formula, shown in general formula (1) below, based on the composition of the monomer components that make up the acrylic adhesive polymer.

1/Tg=W ₁ /Tg ₁ +W ₂ /Tg ₂ +...+W _n /Tg _n General formula (1)

[In the above general formula (1), Tg is the glass transition temperature (unit: K) of the acrylic adhesive polymer, Tg _i (i = 1, 2, ... n) is the glass transition temperature (unit: K) when monomer i forms a homopolymer, and W _i (i = 1, 2, ... n) represents the mass fraction of monomer i in all monomer components.]

The glass transition temperature (Tg) of homopolymers can be found, for example, in "Polymer Handbook" (edited by J. Brandrup and E.H. Immergut, Interscience Publishers).

When the glass transition temperature (Tg) of the main chain of the hydroxyl-containing acrylic adhesive polymer (copolymer) is below -65°C, particularly if the amount of crosslinking agent (described below) added is small, the adhesive layer 2 containing the copolymer becomes excessively soft, and when cool-expanding is performed, the edge portions (four-sided periphery) of the cleaved die bond film may not be partially peeled from the adhesive layer 2 of the dicing tape 10. Furthermore, during the pick-up process after ultraviolet irradiation, the semiconductor chip with the die bond film may be difficult to peel from the adhesive layer 2, or adhesive residue (contamination) may occur on the surface of the die bond film 3. As a result, the yield of non-defective semiconductor chips with the die bond film decreases.

On the other hand, if the glass transition temperature (Tg) exceeds -45°C, particularly if a large amount of the crosslinking agent described below is added, the pressure-sensitive adhesive layer 2 containing these becomes excessively hard, resulting in poor wettability and conformability to the die bond film 3 and poor initial adhesion to the die bond film 3. As a result, in the cool expansion step, the die bond film 3 peels excessively from the pressure-sensitive adhesive layer 2, and sufficient external stress cannot be applied to the die bond film 3 via the pressure-sensitive adhesive layer 2. This may result in the die bond film 3 not being able to be cleanly cleaved, or the kerf width may not be sufficiently secured, or the kerf width may vary. As a result, the pickup yield of semiconductor chips with die bond films decreases. The glass transition temperature (Tg) is preferably in the range of -63°C or higher and -51°C or lower, more preferably in the range of -61°C or higher and -54°C or lower.

Examples of the (meth)acrylic acid alkyl ester monomer include those having 6 to 18 carbon atoms, such as hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Examples of suitable monomers include tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate, as well as monomers having 5 or fewer carbon atoms, such as pentyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate. Among these, 2-ethylhexyl acrylate is preferred, and it is preferably contained in an amount of 40% by mass or more and 85% by mass or less of the total amount of monomer components constituting the main chain of the hydroxyl group-containing acrylic adhesive polymer (copolymer).

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. The purpose of copolymerizing the hydroxyl group monomer is, first, to provide an addition reaction site (—OH) for introducing an active energy ray-reactive carbon-carbon double bond, which will be described later, into the acrylic adhesive polymer by an addition reaction, and, second, to react the hydroxyl group with an isocyanate group (—NCO) of a polyisocyanate crosslinking agent, which will be described later, to polymerize the acrylic adhesive polymer and provide a crosslinking reaction site for imparting cohesive strength and appropriate hardness to the adhesive layer 2 before active energy ray irradiation. When the active energy ray-reactive carbon-carbon double bond is introduced by an addition reaction using the hydroxyl group possessed by the acrylic adhesive polymer, it is preferable, as a guideline, to adjust the content of the hydroxyl group monomer to, for example, a range of 16.4 mass% to 34.4 mass% with respect to the total amount of copolymer monomer components. In other words, adjusting the content of hydroxyl group monomers in the copolymer within the above range is preferable because it makes it easier to control the hydroxyl group value of the acrylic adhesive polymer and the equivalent ratio (-NCO/-OH) of the isocyanate groups (-NCO) in the polyisocyanate crosslinking agent described below to the hydroxyl groups (-OH) in the acrylic adhesive polymer, both of which are constituent elements of the pressure-sensitive adhesive composition of the present invention, within the specified ranges described above.

The above-mentioned acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group is most preferably obtained by copolymerizing the above-mentioned acrylic adhesive polymer having a hydroxyl group, followed by an addition reaction with a compound having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound) capable of undergoing an addition reaction with the hydroxyl group in the side chain of the copolymer, from the standpoints of ease of reaction tracking (control stability) and technical difficulty. Examples of such compounds having an isocyanate group and a carbon-carbon double bond (active energy ray-reactive compound) include isocyanate compounds having a (meth)acryloyloxy group. Specific examples include 2-methacryloyloxyethyl isocyanate, 4-methacryloyloxy-n-butyl isocyanate, 2-acryloyloxyethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate.

The above addition reaction is preferably carried out in the presence of an organometallic catalyst to promote the reaction. As such an organometallic catalyst, it is preferable to use at least one selected from the group consisting of zirconium-containing organic compounds, titanium-containing organic compounds, and tin-containing organic compounds. The amount of organometallic catalyst is not particularly limited, but is typically preferably in the range of 0.01 to 5 parts by weight per 100 parts by weight of the acrylic adhesive polymer.

Furthermore, in the above addition reaction, it is preferable to use a polymerization inhibitor so that the reactivity of the carbon-carbon double bond to active energy rays is maintained. A quinone-based polymerization inhibitor such as hydroquinone monomethyl ether is preferred as such a polymerization inhibitor. The amount of polymerization inhibitor is not particularly limited, but is typically preferably in the range of 0.01 to 0.1 parts by weight per 100 parts by weight of the acrylic adhesive polymer.

When carrying out the addition reaction, the acrylic adhesive polymer is crosslinked with a polyisocyanate-based crosslinking agent added later, further increasing its molecular weight and imparting cohesive strength and appropriate hardness to the adhesive layer 2 prior to irradiation with active energy rays. While it is necessary to ensure that a desired amount of hydroxyl groups remain in the adhesive composition, it is also necessary to control the concentration of active energy ray-reactive carbon-carbon double bonds within a desired range. Both of these considerations must be taken into account. For example, when reacting an isocyanate compound having a (meth)acryloyloxy group with a copolymer having a hydroxyl group in its side chain, it is preferable to carry out the addition reaction using an amount of the isocyanate compound having a (meth)acryloyloxy group that provides a ratio of 37 mol % to 84 mol % relative to the hydroxyl group-containing monomer contained in the acrylic adhesive polymer.

In addition to the (meth)acrylic acid alkyl ester monomer and hydroxyl group-containing monomer, the above acrylic adhesive polymer may also contain other copolymerizable monomer components copolymerized therein as needed for purposes such as adjusting adhesive strength and glass transition temperature (Tg). Examples of such other copolymerizable monomer components include monomers having a functional group, such as carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide; amino group-containing monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; and glycidyl group-containing monomers such as glycidyl (meth)acrylate. The content of such monomers having functional groups is not particularly limited, but is preferably in the range of 0.5% by mass or more and 30% by mass or less based on the total amount of copolymerizable monomer components.

When a monomer having a functional group other than a hydroxyl group is copolymerized, an active energy ray-reactive carbon-carbon double bond can be introduced into the acrylic adhesive polymer using the functional group. For example, if the acrylic adhesive polymer has a carboxyl group in its side chain, the active energy ray-reactive carbon-carbon double bond can be introduced into the acrylic adhesive polymer by reacting it with an active energy ray-reactive compound such as glycidyl (meth)acrylate or 2-(1-aziridinyl)ethyl (meth)acrylate. If the acrylic adhesive polymer has a glycidyl group in its side chain, the active energy ray-reactive carbon-carbon double bond can be introduced into the acrylic adhesive polymer by reacting it with an active energy ray-reactive compound such as (meth)acrylic acid. However, when a monomer having a functional group other than a hydroxyl group is copolymerized and the active energy ray-reactive carbon-carbon double bond is introduced into the acrylic adhesive polymer using the functional group, it is preferable to adjust the content of the hydroxyl group monomer to be copolymerized simultaneously, for example, within a range of 2.5% by mass to 8.4% by mass, based on the total amount of copolymer monomer components. This is advantageous because it makes it easier to control the hydroxyl value of the acrylic adhesive polymer and the equivalent ratio (-NCO/-OH) between the isocyanate groups (-NCO) in the polyisocyanate crosslinking agent (described below) and the hydroxyl groups (-OH) in the acrylic adhesive polymer within the specified ranges described above.

Furthermore, the acrylic adhesive polymer having the above functional groups may contain other copolymerizable monomer components as needed to improve cohesive strength, heat resistance, etc., within the scope of the present invention without impairing its effects. Specific examples of such other copolymerizable monomer components include cyano group-containing monomers such as (meth)acrylonitrile; olefin-based monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene; vinyl ester-based monomers such as vinyl acetate and vinyl propionate; vinyl ether-based monomers such as methyl vinyl ether and ethyl vinyl ether; halogen atom-containing monomers such as vinyl chloride and vinylidene chloride; (meth)acrylonitrile and other cyano group-containing monomers; ) Alkoxy group-containing monomers such as methoxyethyl acrylate and ethoxyethyl (meth)acrylate, and monomers having a nitrogen atom-containing ring such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine. These other copolymerizable monomer components may be used alone or in combination of two or more.

In this embodiment, suitable copolymers having hydroxyl groups obtained by copolymerizing the above-mentioned monomers specifically include, but are not limited to, a binary copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, a terpolymer of 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, and methacrylic acid, a terpolymer of 2-ethylhexyl acrylate, n-butyl acrylate, and 2-hydroxyethyl acrylate, a terpolymer of 2-ethylhexyl acrylate, methyl methacrylate, and 2-hydroxyethyl acrylate, a quaternary copolymer of 2-ethylhexyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, and methacrylic acid, and a quaternary copolymer of 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, and methacrylic acid. It is then preferable to add 2-methacryloyloxyethyl isocyanate, an isocyanate compound having a (meth)acryloyloxy group, to these suitable copolymers to produce an acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group.

The acrylic adhesive polymer having active energy ray-reactive carbon-carbon double bonds and hydroxyl groups thus obtained has a hydroxyl value in the range of 12.0 mgKOH/g to 40.5 mgKOH/g. If the hydroxyl value is less than 12.0 mgKOH/g, the excessively low hydroxyl value results in insufficient crosslinking after the addition of the polyisocyanate-based crosslinking agent, resulting in insufficient cohesive strength of the adhesive layer 2 before active energy ray irradiation. This can result in adhesive residue remaining on the die bond film 3 during pickup or on the SUS ring frame when the dicing tape 10 is peeled from the ring frame after the completion of a series of processes. Furthermore, because the adhesive layer 2 cannot be imparted with adequate hardness before active energy ray irradiation, the edge portions (four-sided periphery) of the cleaved die bond film may not be partially peeled from the adhesive layer 2 of the dicing tape 10 during cool expansion. As a result, the effect of improving pickup performance compared to conventional methods is not observed, or pickup performance is reduced.

On the other hand, if the hydroxyl value exceeds 40.5 mg KOH/g, particularly if the amount of polyisocyanate-based crosslinking agent added is small, the residual hydroxyl group concentration after the crosslinking reaction in the active energy ray-curable adhesive composition may become excessively high, potentially resulting in unnecessarily strong initial adhesion of the adhesive layer 2 to the die bond film 3. In this case, when cool expanding is performed, the edge portions (four-sided periphery) of the cleaved die bond film may not be partially peeled from the adhesive layer 2 of the dicing tape 10. Furthermore, in the pick-up process after active energy ray irradiation, the semiconductor chip with the die bond film may be difficult to peel from the adhesive layer 2 in the adhesion portions where peeling between the adhesive layer 2 and the die bond film 3 did not occur during the previous expansion process. As a result, the pick-up yield of semiconductor chips with die bond films may decrease. The hydroxyl value is preferably in the range of 12.5 mgKOH/g or more and 40.1 mgKOH/g or less, and more preferably in the range of 12.7 mgKOH/g or more and 30.1 mgKOH/g or less.

When the hydroxyl value is in the range of 12.0 mgKOH/g or more and 40.5 mgKOH/g, by combining it with the addition of a specific amount of polyisocyanate-based crosslinking agent described below, it is possible to impart cohesive strength as well as appropriate hardness and polarity to the pressure-sensitive adhesive layer 2. This means that while the initial adhesion of the pressure-sensitive adhesive layer 2 to the die-bonding film 3 is appropriately maintained, it is possible to form an appropriate peel state from the pressure-sensitive adhesive layer 2 at the edge portion of the cleaved die-bonding film 3 in the cool expanding step without interfering with the effect of reducing the adhesive strength of the pressure-sensitive adhesive layer 2 by irradiating the pressure-sensitive adhesive layer with active energy rays.

Furthermore, the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group is not particularly limited, but preferably has an acid value in the range of 0 mgKOH/g or more and 9.0 mgKOH/g or less. When the acid value is within the above range, the initial adhesion of the pressure-sensitive adhesive layer 2 to the die-bonding film 3 is appropriately maintained, while the effect of reducing the adhesive strength of the pressure-sensitive adhesive layer 2 by active energy ray irradiation is not hindered, and it becomes easy to form an appropriate peel state from the pressure-sensitive adhesive layer 2 at the edge portion of the cleaved die-bonding film 3 in the cool expanding step. The acid value is more preferably in the range of 2.0 mgKOH/g or more and 8.2 mgKOH/g or less, and even more preferably in the range of 2.5 mgKOH/g or more and 5.6 mgKOH/g or less.

Furthermore, the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group preferably has a weight-average molecular weight Mw in the range of 200,000 to 2,000,000. Here, the weight-average molecular weight Mw refers to the standard polystyrene equivalent value measured by gel permeation chromatography. If the weight-average molecular weight Mw of the acrylic adhesive polymer is less than 200,000, it is difficult to obtain a solution of an active energy ray-curable acrylic adhesive composition with a high viscosity of several thousand to several tens of thousands of cP, taking into account factors such as coatability, and this is undesirable. Furthermore, the cohesive strength of the adhesive layer 2 before active energy ray irradiation is reduced, which may contaminate the surface of the die bond film of the semiconductor wafer with the die bond film 3 when the semiconductor chip with the die bond film 3 is detached from the adhesive layer 2 after active energy ray irradiation. Furthermore, when the dicing tape 10 is peeled from the SUS ring frame after the completion of a series of processes, adhesive residue may remain on the ring frame.

On the other hand, if the weight-average molecular weight Mw exceeds 2,000,000, it is difficult to mass-produce the active energy ray-curable acrylic adhesive polymer. For example, the active energy ray-curable acrylic adhesive polymer may gel during synthesis, which is undesirable. Furthermore, if the amount of polyisocyanate-based crosslinking agent added is large, the wettability and conformability of the adhesive layer 2 to the die bond film 3 before active energy ray irradiation decreases, and the initial adhesion strength decreases. Therefore, in the cool expansion process, the die bond film 3 may peel excessively from the adhesive layer 2, and sufficient external stress cannot be applied to the die bond film 3 via the adhesive layer 2. This may result in the die bond film 3 not being able to be cleanly cleaved, or the kerf width may not be sufficiently secured, or the kerf width may vary. As a result, the pickup yield of semiconductor chips with die bond films decreases. The weight-average molecular weight Mw is preferably in the range of 300,000 to 1,000,000.

[Crosslinking agent]
The active energy ray-curable pressure-sensitive adhesive composition of the present embodiment further contains a polyisocyanate-based crosslinking agent to crosslink the above-mentioned acrylic pressure-sensitive adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group to increase the molecular weight and impart cohesive strength and appropriate hardness to the pressure-sensitive adhesive layer 2 before irradiation with active energy rays. Examples of the polyisocyanate-based crosslinking agent include a polyisocyanate compound having an isocyanurate ring, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with tolylene diisocyanate, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with xylylene diisocyanate, and an adduct polyisocyanate compound obtained by reacting trimethylolpropane with isophorone diisocyanate. These may be used alone or in combination of two or more. Among these, from the viewpoint of versatility, an adduct polyisocyanate compound obtained by reacting trimethylolpropane with tolylene diisocyanate and/or an adduct polyisocyanate compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate are preferably used.

Adduct polyisocyanate compounds obtained by reacting trimethylolpropane with tolylene diisocyanate can be commercially available products such as Coronate L-45E, Coronate L-55E, and Coronate L (all trade names) manufactured by Tosoh Corporation, and Takenate D101E (trade name) manufactured by Mitsui Chemicals, Inc. Also, adduct polyisocyanate compounds obtained by reacting trimethylolpropane with hexamethylene diisocyanate can be commercially available products such as Coronate HL (trade name) manufactured by Tosoh Corporation and Takenate D160N (trade name) manufactured by Mitsui Chemicals, Inc.

The polyisocyanate crosslinking agent is contained in an amount ranging from 2.4 to 7.0 parts by mass per 100 parts by mass of the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, and having a hydroxyl value ranging from 12.0 to 40.5 mgKOH/g, as described above, and is adjusted so that the equivalent ratio (-NCO/-OH) of the isocyanate groups (-NCO) of the polyisocyanate crosslinking agent to the hydroxyl groups (-OH) of the acrylic adhesive polymer is in the range of from 0.14 to 1.32.

When the equivalent ratio (-NCO/-OH) is less than 0.14, particularly when the hydroxyl value of the acrylic adhesive polymer is small, it is not possible to impart an appropriate hardness to the pressure-sensitive adhesive layer 2 before the active energy ray irradiation, and therefore, when cool expanding is performed, there is a risk that the edge portions (surrounding portions on all four sides) of the cleaved die-bonding film will not be partially peeled from the pressure-sensitive adhesive layer 2 of the dicing tape 10. As a result, the effect of improving the pick-up property compared to conventional methods is not seen, or the pick-up property is reduced.
Furthermore, particularly when the hydroxyl value of the acrylic adhesive polymer is large, there is a risk that the edge portion (four-sided periphery) of the cleaved die bond film will not be partially peeled from the adhesive layer 2 of the dicing tape 10 when cool expanding, and the concentration of residual hydroxyl groups after the crosslinking reaction in the active energy ray-curable adhesive composition will become excessively large, which may result in an unnecessarily high initial adhesion of the adhesive layer 2 to the die bond film 3. As a result, in the pick-up step after active energy ray irradiation, the semiconductor chip with the die bond film will be difficult to peel from the adhesive layer 2 in the adhesion portion where peeling of the adhesive layer 2 and the die bond film 3 did not occur due to the expansion in the previous step, and the pick-up yield of the semiconductor chip with the die bond film will decrease.

On the other hand, if the equivalent ratio (-NCO/-OH) exceeds 1.32, the pressure-sensitive adhesive layer 2 before active energy ray irradiation becomes excessively hard, thereby reducing the wettability and followability of the pressure-sensitive adhesive layer 2 with respect to the die bond film 3 before active energy ray irradiation and reducing the initial adhesion strength. Therefore, in the cool expansion step, the die bond film 3 peels excessively from the pressure-sensitive adhesive layer 2, and sufficient external stress cannot be applied to the die bond film 3 via the pressure-sensitive adhesive layer 2. This may result in the die bond film 3 not being able to be cleanly cleaved, or the kerf width may not be sufficiently secured, or the kerf width may vary. Furthermore, the increased rigidity of the pressure-sensitive adhesive layer 2 increases the flexural modulus of the dicing tape 10. In the pick-up step, even if the dicing tape 10 is pushed up with a push-up jig, the dicing tape 10 only bends slightly, which may make it difficult to promote peeling of the four edges of the semiconductor chip with the die bond film from the pressure-sensitive adhesive layer 2. As a result, the pick-up yield of the semiconductor chip with the die bond film decreases. Furthermore, the adhesive strength of the adhesive layer 2 to the SUS ring frame may be insufficient, and the dicing tape 10 may peel off from the SUS ring frame during expansion, which may prevent the expansion process from being carried out normally.

In this way, the pressure-sensitive adhesive layer 2 containing the active energy ray-curable pressure-sensitive adhesive composition in which the amount of polyisocyanate-based crosslinking agent added and the equivalent ratio (-NCO/-OH) have been adjusted has a hardness that allows it to transmit a moderate impact to the interface between the edge of the die bond film and the pressure-sensitive adhesive layer 2 directly below it at the moment the die bond film 3 is cleaved in the low-temperature environment during cool expansion, and a cohesive force that allows it to transmit stress in a direction away from the die bond film 3, while also having a moderate initial adhesion to the die bond film 3. Therefore, by subjecting the dicing tape 10 in which the pressure-sensitive adhesive layer 2 is laminated to the above-mentioned base film 1 to the cool expansion process, the die bond film 3 can be cleanly cleaved, and the cleaved die bond film can be appropriately and intentionally partially peeled from the pressure-sensitive adhesive layer 2 of the dicing tape 10 at its edge portions (surrounding portions on all four sides). The equivalent ratio (-NCO/-OH) is preferably in the range of 0.30 to 0.90.

Here, the equivalent ratio (NCO/OH) of the isocyanate groups (NCO) of the polyisocyanate crosslinking agent to the hydroxyl groups (OH) of the acrylic adhesive polymer is a theoretically calculated value obtained by dividing the total number of moles of isocyanate groups, which is calculated from the content of the polyisocyanate crosslinking agent in the active energy ray-curable adhesive composition and the average number of isocyanate groups per molecule of the polyisocyanate crosslinking agent, by the total number of moles of hydroxyl groups in the acrylic adhesive polymer after the active energy ray-reactive carbon-carbon double bonds have been introduced. For example, when an isocyanate compound having a (meth)acryloyloxy group is added to an acrylic adhesive polymer having hydroxyl groups as a base polymer to introduce active energy ray-reactive carbon-carbon double bonds, the total number of moles of hydroxyl groups is the value obtained by subtracting the number of moles of hydroxyl groups theoretically consumed by the crosslinking reaction with the isocyanate groups of the added isocyanate compound having a (meth)acryloyloxy group (= the number of moles of isocyanate groups of the isocyanate compound having a (meth)acryloyloxy group) from the total number of moles of hydroxyl groups in the acrylic adhesive polymer as the base polymer.

In addition, in an active energy ray-curable pressure-sensitive adhesive composition in which the amount of polyisocyanate-based crosslinking agent added and the equivalent ratio (-NCO/-OH) are adjusted to the above-mentioned ranges, the concentration of residual hydroxyl groups after the crosslinking reaction per 1 g of the active energy ray-curable pressure-sensitive adhesive composition is preferably in the range of 0 mmol to 0.60 mmol, and more preferably in the range of 0.02 mmol to 0.40 mmol. Here, the concentration of residual hydroxyl groups after the crosslinking reaction per 1 g of the active energy ray-curable pressure-sensitive adhesive composition is the total number of moles of hydroxyl groups in the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, minus the number of moles of hydroxyl groups theoretically consumed by the crosslinking reaction with the isocyanate groups of the added polyisocyanate-based crosslinking agent (= the number of moles of isocyanate groups in the crosslinking agent), converted to a value per 1 g of the active energy ray-curable pressure-sensitive adhesive composition.

When the concentration of residual hydroxyl groups per 1 g of the active energy ray-curable adhesive composition after the crosslinking reaction is within the above range, the initial adhesion of the adhesive layer 2 to the die bond film 3 and the adhesion to the SUS ring frame can be made appropriate. Therefore, by subjecting the dicing tape 10 in which the adhesive layer 2 is laminated to the above-mentioned base film 1 to the cool expansion process, it becomes easy to appropriately and intentionally create a state in which the edge portions (surrounding portions on all four sides) of the cleaved die bond film are partially peeled from the adhesive layer 2 of the dicing tape 10.

After forming the adhesive layer 2 from the active energy ray-curable adhesive composition, the aging conditions for reacting the polyisocyanate-based crosslinking agent with the hydroxyl-containing acrylic adhesive polymer are not particularly limited, but may be set appropriately, for example, at a temperature in the range of 23°C to 80°C and for a time in the range of 24 hours to 168 hours.

[Photopolymerization initiator]
The active energy ray-curable pressure-sensitive adhesive composition of the present embodiment contains a photopolymerization initiator that generates radicals upon irradiation with active energy rays. The photopolymerization initiator generates radicals upon exposure to active energy rays irradiated onto the active energy ray-curable acrylic pressure-sensitive adhesive composition, thereby initiating a crosslinking reaction of carbon-carbon double bonds in the active energy ray-curable acrylic pressure-sensitive adhesive polymer.

The photopolymerization initiator is not particularly limited, and conventionally known initiators can be used. Specific examples include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime ester-based photopolymerization initiators. Examples of alkylphenone-based photopolymerization initiators include α-hydroxyalkylphenone-based radical polymerization initiators, α-hydroxyacetophenone-based radical polymerization initiators, α-aminoalkylphenone-based radical polymerization initiators, and benzyl methyl ketal-based radical polymerization initiators.

The above photopolymerization initiators may be used alone or in combination of two or more types as long as the effects of the present invention are achieved. However, in the active energy ray-curable adhesive composition of this embodiment, from the viewpoint of effectively reducing both the adhesive strength A after ultraviolet light irradiation in the presence of oxygen and the adhesive strength B after ultraviolet light irradiation in the absence of oxygen, it is preferable to include at least three types of photopolymerization initiators: an α-aminoalkylphenone photopolymerization initiator (a), an alkylphenone photopolymerization initiator other than an α-aminoalkylphenone photopolymerization initiator (b), and an acylphosphine oxide photopolymerization initiator (c).

In the present invention, "adhesion strength A after UV irradiation in the presence of oxygen" refers to the adhesive strength measured when the release liner of the dicing tape 10 is peeled off, the adhesive layer 2 is directly irradiated with UV rays as active energy rays while the adhesive layer 2 is exposed to air (in the presence of oxygen), and then the tape is attached to an adherend (SUS304 BA plate). When a semiconductor chip with a die bond film is picked up, the "portion of the adhesive layer 2 from which the die bond film 3 was peeled off during expansion" is irradiated with UV rays while exposed to air. This model simulates the adhesive strength of the dicing tape 10 to the die bond film 3 when the die bond film 3 is re-attached to the adhesive layer 2 after being irradiated with UV rays while exposed to air, and represents the ease of peeling of the re-attached portion during the pickup process. The smaller the adhesive strength value, the weaker the re-adhesion force, making it easier to peel the semiconductor chip with the die bond film from the adhesive layer 2 of the dicing tape 10.

Furthermore, "adhesive strength B after ultraviolet irradiation in the absence of oxygen" refers to the adhesive strength measured after peeling off the release liner of the dicing tape 10, attaching the adhesive layer 2 side to an adherend (SUS304 BA plate), and irradiating the adhesive layer 2 with ultraviolet light as active energy rays through the base film 1 of the dicing tape 10 in a state where the adhesive layer 2 is not exposed to air (in the absence of oxygen). When picking up a semiconductor chip with a die bond film, the "portion of the adhesive layer 2 where the die bond film 3 that was cleaved during expansion and adhered without peeling" is irradiated with ultraviolet light in a state where it is not exposed to air. This is a model that assumes the adhesive strength of the dicing tape 10 to the die bond film 3 when ultraviolet light is irradiated to the adhesive layer 2 in such a state where it is not exposed to air, and represents the ease of peeling of the adhered portion other than the re-fixed portion in the pick-up process. The smaller the adhesive strength value, the easier it is to peel the semiconductor chip with a die bond film from the adhesive layer 2 of the dicing tape 10. The method for measuring these adhesive forces will be described in detail later.

Specific examples of the α-aminoalkylphenone photopolymerization initiator (a) include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: Omnirad 907, manufactured by IGM Resins B.V.), 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (trade name: Omnirad 369, manufactured by IGM Resins B.V.), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one (trade name: Omnirad 379EG, manufactured by IGM Resins B.V.). These may be used alone or in combination of two or more.

Of these, 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone or 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one is preferably used as the α-aminoalkylphenone photopolymerization initiator (a).

The above-mentioned α-aminoalkylphenone photopolymerization initiator (a) is particularly effective in reducing the adhesive strength A of the adhesive layer 2 after irradiation with ultraviolet light in the presence of oxygen. However, on the other hand, the adhesive strength B of the adhesive layer 2 after irradiation with ultraviolet light in the absence of oxygen tends to increase as the content of the above-mentioned photopolymerization initiator (a) increases. Therefore, it is preferable to use it in combination with an alkylphenone photopolymerization initiator (b) other than the α-aminoalkylphenone photopolymerization initiator and an acylphosphine oxide photopolymerization initiator (c), which are effective in reducing the adhesive strength B after irradiation with ultraviolet light in the absence of oxygen, as described below, and it is also preferable to keep the content of the above-mentioned photopolymerization initiator (a) within the range described below.

As mentioned above, examples of alkylphenone-based photopolymerization initiators (b) other than the above-mentioned α-aminoalkylphenone-based photopolymerization initiators include α-hydroxyalkylphenone-based radical polymerization initiators, α-hydroxyacetophenone-based radical polymerization initiators, and benzyl methyl ketal-based radical polymerization initiators. These may be used alone or in combination of two or more.

Specific examples of α-hydroxyalkylphenone photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone (trade name: Omnirad 184, manufactured by IGM Resins B.V.).

Specific examples of α-hydroxyacetophenone-based photopolymerization initiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one (trade name: Omnirad 1173, manufactured by IGM Resins B.V.), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (trade name: Omnirad 2959, manufactured by IGM Resins B.V.), and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one (trade name: Omnirad 127, manufactured by IGM Resins B.V.).

Specific examples of benzyl methyl ketal photopolymerization initiators include 2,2'-dimethoxy-1,2-diphenylethan-1-one (e.g., Omnirad 651, manufactured by IGM Resins B.V.).

Among these, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, or 2,2'-dimethoxy-1,2-diphenylethan-1-one are preferably used as alkylphenone photopolymerization initiators (b) other than α-aminoalkylphenone photopolymerization initiators.

Alkylphenone-based photopolymerization initiators (b) other than the above-mentioned α-aminoalkylphenone-based photopolymerization initiators are particularly effective in reducing the adhesive strength B of the pressure-sensitive adhesive layer 2 after irradiation with ultraviolet light in the absence of oxygen. Furthermore, although the effect of reducing the adhesive strength A after irradiation with ultraviolet light in the presence of oxygen is inferior to that of the above-mentioned α-aminoalkylphenone-based photopolymerization initiator (a), a certain degree of reduction can be achieved depending on the content. Therefore, by using them in combination with the above-mentioned α-aminoalkylphenone-based photopolymerization initiator (a), it becomes easier to reduce the adhesive strength B after irradiation with ultraviolet light in the absence of oxygen while further supplementarily improving the effect of reducing the adhesive strength after irradiation with ultraviolet light in the presence of oxygen.

Specific examples of the acylphosphine oxide photopolymerization initiator (c) include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name Omnirad TPO, manufactured by IGM Resins B.V.), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (trade name Omnirad 819, manufactured by IGM Resins B.V.), and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name Omnirad TPO, manufactured by IGM Resins B.V.). These may be used alone or in combination of two or more.

Among these, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide is preferably used as the acylphosphine oxide photopolymerization initiator (c).

The acylphosphine oxide photopolymerization initiator (c) has an absorption edge extending to wavelengths of 400 nm or more, resulting in a fast curing rate and being particularly effective in further reducing the adhesive strength B of the adhesive layer 2 after UV irradiation in the absence of oxygen. Furthermore, although its effect in reducing the adhesive strength A after UV irradiation in the presence of oxygen is inferior to that of the α-aminoalkylphenone photopolymerization initiator (a), it can still achieve a certain level of reduction depending on its content. Therefore, by using it in combination with the α-aminoalkylphenone photopolymerization initiator (a) and an alkylphenone photopolymerization initiator (b) other than the α-aminoalkylphenone photopolymerization initiator, it becomes easy to further enhance the effect of reducing the adhesive strength A after UV irradiation in the presence of oxygen while further enhancing the effect of reducing the adhesive strength B after UV irradiation in the absence of oxygen.

Specific examples of suitable combinations of photopolymerization initiators containing at least three types of photopolymerization initiators, namely, the α-aminoalkylphenone photopolymerization initiator (a), the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and the acylphosphine oxide photopolymerization initiator (c), include:
(1) A combination of three types of photopolymerization initiators: (a): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one/photopolymerization initiator (b): 1-hydroxycyclohexyl phenyl ketone/photopolymerization initiator (c): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide;
(2) a combination of three types of photopolymerization initiators: (a): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one/photopolymerization initiator (b): 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one/photopolymerization initiator (c): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide;
(3) Four types of combinations of photopolymerization initiator (a): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one/photopolymerization initiator (b): 1-hydroxycyclohexyl phenyl ketone and 2,2'-dimethoxy-1,2-diphenylethan-1-one/photopolymerization initiator (c): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
(4) Four types of combinations of photopolymerization initiator (a): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one/photopolymerization initiator (b): 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one/photopolymerization initiator (c): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
(5) Four types of combinations of photopolymerization initiator (a): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one / photopolymerization initiator (b): 2-hydroxy-1-{4-[4-2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one and 2,2'-dimethoxy-1,2-diphenylethan-1-one / photopolymerization initiator (c): bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,
etc.

As described above, the active energy ray-curable adhesive composition of this embodiment preferably contains at least three types of photopolymerization initiators: (a) an α-aminoalkylphenone-based photopolymerization initiator; (b) an alkylphenone-based photopolymerization initiator other than an α-aminoalkylphenone-based photopolymerization initiator; and (c) an acylphosphine oxide-based photopolymerization initiator. In this case, due to the synergistic effect of the functions of the respective photopolymerization initiators, (1) when the adhesive layer 2 is irradiated with ultraviolet light in an oxygen-free state, not only does the curing of the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond contained in the adhesive composition proceed sufficiently within a specified time, but (2) even when the adhesive layer 2 is irradiated with ultraviolet light in an aerobic state, the decrease in curing rate due to the effects of oxygen inhibition is significantly suppressed, making it easy to proceed with the curing of the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond contained in the adhesive composition to the desired level within a specified time. As a result, first, (1) when ultraviolet light is irradiated onto the adhesive surface of the pressure-sensitive adhesive layer 2 to which the die-bonding film (adhesive layer) 3 is attached (the surface that remains in contact without peeling even after the expanding process), it becomes easy to impart an adhesive strength B after ultraviolet light irradiation in the absence of oxygen, as described below, within the desired range. Furthermore, (2) when ultraviolet light is irradiated onto the peeled portion of the pressure-sensitive adhesive layer 2 from which the cleaved die-bonding film 3 was formed in the expanding process, it becomes easy to impart an adhesive strength A after ultraviolet light irradiation in the presence of oxygen, as described below, within the desired range, while avoiding the adhesive strength not decreasing sufficiently and being maintained at a high value due to inhibition of polymerization of the acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond by oxygen contained in the surrounding air, as seen in conventional dicing tape 10.

As a result, in the pick-up process, when a suction collet is brought into contact with the semiconductor chip from above after UV irradiation of the adhesive layer 2 in order to pick up the semiconductor chip with the die bond film, the edge portion of the die bond film of the semiconductor chip with the die bond film that was partially peeled off from the adhesive layer 2 by the previous expanding process can be strongly re-adhered to the adhesive layer 2, which has not cured sufficiently due to oxygen inhibition. This significantly reduces the effect. In other words, the re-adhesion force can be weakened to a level where the dicing tape 10 can be easily peeled off by pushing up with a jig from the underside. Furthermore, a suitable adhesive strength B can be imparted after UV irradiation in the absence of oxygen to the surface where the adhesive layer 2 and the die bond film of the semiconductor chip with the die bond film are in close contact without peeling, making it possible to smoothly pick up the semiconductor chip with the die bond film from the adhesive layer 2 thereafter.

The amount of the photopolymerization initiator (or the total amount when two or more types are used in combination) added is preferably in the range of 1.2 to 12.0 parts by mass per 100 parts by mass of the solids content of the active energy ray-curable acrylic adhesive polymer. If the amount of photopolymerization initiator added is less than 1.2 parts by mass, the photoreactivity to active energy rays is insufficient, and the photoradical crosslinking reaction of the acrylic adhesive polymer does not occur sufficiently even when irradiated with active energy rays. As a result, the adhesive strength reduction effect of the adhesive layer 2 after UV irradiation in both aerobic and anaerobic conditions is reduced, which may increase the likelihood of semiconductor chip pickup failure. On the other hand, if the amount of photopolymerization initiator added exceeds 12.0 parts by mass, the effect saturates, which is undesirable from an economic standpoint. Furthermore, depending on the type of photopolymerization initiator, the adhesive strength B of the adhesive layer 2 after UV irradiation in the absence of oxygen may be greater than the desired value, which may increase the likelihood of semiconductor chip pickup failure with the die bond film.

In a preferred embodiment containing three types of photopolymerization initiators, the respective amounts of the α-aminoalkylphenone photopolymerization initiator (a), the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and the acylphosphine oxide photopolymerization initiator (c) added are preferably adjusted so that, relative to 100 parts by mass of the solids content of the active energy ray-curable acrylic adhesive polymer, the α-aminoalkylphenone photopolymerization initiator (a) is in the range of 0.8 parts by mass to 5.0 parts by mass, the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b) is in the range of 0.2 parts by mass to 5.0 parts by mass, and the acylphosphine oxide photopolymerization initiator (c) is in the range of 0.2 parts by mass to 2.0 parts by mass.

If the amount of the α-aminoalkylphenone photopolymerization initiator (a) added is less than 0.8 parts by mass, the adhesive strength A of the adhesive layer 2 after UV irradiation in the presence of oxygen may not decrease to the desired value. On the other hand, if the amount of the α-aminoalkylphenone photopolymerization initiator (a) added is more than 5.0 parts by mass, the adhesive strength B of the adhesive layer 2 after UV irradiation in the absence of oxygen may be greater than the desired value. Furthermore, the storage stability of the dosing tape 10 may be impaired. If the amount of the alkylphenone photopolymerization initiator (b) other than the α-aminoalkylphenone photopolymerization initiator added is less than 0.2 parts by mass, the adhesive strength of the adhesive layer 2 after UV irradiation in both the presence of oxygen and the absence of oxygen may not decrease to the desired value. If the amount of the alkylphenone photopolymerization initiator (b) other than the α-aminoalkylphenone photopolymerization initiator added is more than 5.0 parts by mass, the effect of the alkylphenone photopolymerization initiator (b) other than the α-aminoalkylphenone photopolymerization initiator saturates, which is undesirable from an economic standpoint. Furthermore, the storage stability of the dosing tape 10 may be impaired. If the amount of the acylphosphine oxide photopolymerization initiator (c) added is less than 0.2 parts by mass, the adhesive strength of the pressure-sensitive adhesive layer 2 may not decrease to the desired value after ultraviolet irradiation in the presence and absence of oxygen. If the amount of the acylphosphine oxide photopolymerization initiator (c) added is more than 2.0 parts by mass, the effect saturates, which is undesirable from an economic standpoint. Furthermore, depending on the amounts of the other photopolymerization initiators (a) and (b) added, the storage stability of the dousing tape 10 may be impaired.

When the amounts of the α-aminoalkylphenone photopolymerization initiator (a), the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and the acylphosphine oxide photopolymerization initiator (c) added are adjusted within the above ranges, as described above, the adhesive strength of the adhesive layer 2 can be reduced to a desired level by irradiating it with ultraviolet light in both the presence and absence of oxygen, making it possible to successfully pick up the semiconductor chip with the die bond film from the adhesive layer 2 in the pick-up process.

In addition, compounds such as dimethylaminoethyl methacrylate and 4-dimethylaminobenzoic acid isoamyl may be added to the active energy ray-curable acrylic pressure-sensitive adhesive composition as a sensitizer for the photopolymerization initiator, as long as the effects of the present invention are not impaired.

[others]
To the active energy ray-curable pressure-sensitive adhesive composition of the present embodiment, additives such as an active energy ray-curable compound (e.g., a polyfunctional urethane acrylate oligomer), a tackifier, a filler, an antioxidant, a colorant, a flame retardant, an antistatic agent, a surfactant, a silane coupling agent, and a leveling agent may be added as needed, within a range that does not impair the effects of the present invention.

[Active energy ray reactive carbon-carbon double bond concentration]
The active energy ray-curable pressure-sensitive adhesive composition of the present embodiment is not particularly limited, but it is preferable that the active energy ray-reactive carbon-carbon double bond concentration is adjusted to be in the range of 0.85 meq to 1.50 meq per 1 g of the active energy ray-curable pressure-sensitive adhesive composition. If the active energy ray-reactive carbon-carbon double bond concentration per 1 g of the active energy ray-curable pressure-sensitive adhesive composition is less than 0.85 meq, when the concentration of residual hydroxyl groups after the crosslinking reaction per 1 g of the active energy ray-curable pressure-sensitive adhesive composition described above is large, the adhesive strength of the pressure-sensitive adhesive layer 2 after ultraviolet irradiation, particularly the adhesive strength A after ultraviolet irradiation in the presence of oxygen, does not decrease sufficiently, and it may become difficult to peel the semiconductor chip with the die bond film from the adhesive layer 2 in the pick-up step.

On the other hand, if the concentration of active energy ray-reactive carbon-carbon double bonds per gram of active energy ray-curable adhesive composition exceeds 1.50 meq, the effect gradually saturates, which is undesirable from an economic standpoint. Furthermore, depending on the copolymerization composition of the acrylic adhesive polymer, gelation may occur during the polymerization or reaction during synthesis, making synthesis difficult. To confirm the carbon-carbon double bond content of an acrylic adhesive polymer, the carbon-carbon double bond content can be calculated by measuring the iodine value of the acrylic adhesive polymer.

When the active energy ray-reactive carbon-carbon double bond concentration is within the range of 0.85 meq or more and 1.50 meq or less per 1 g of the active energy ray-curable pressure-sensitive adhesive composition, as described above, the adhesive strength of the pressure-sensitive adhesive layer 2 can be easily reduced to the desired level by irradiating it with ultraviolet light in both the presence and absence of oxygen, making it easier to successfully pick up the semiconductor chip with the die bond film from the pressure-sensitive adhesive layer 2 in the pick-up step. The active energy ray-reactive carbon-carbon double bond concentration is more preferably within the range of 0.88 meq or more and 1.46 meq or less per 1 g of the active energy ray-curable pressure-sensitive adhesive composition.

[Adhesive strength of adhesive layer]
The adhesive strength A of the pressure-sensitive adhesive layer 2 of the dicing tape 10 to a stainless steel plate (SUS304 BA plate) after irradiation with ultraviolet light under oxygen at 23°C is in the range of 3.50 N/25 mm or less. Here, the adhesive strength A after irradiation with ultraviolet light under oxygen is the adhesive strength of the pressure-sensitive adhesive layer 2 after ultraviolet irradiation, taking into consideration that, as described above, the adhesive strength A after irradiation with ultraviolet light is not sufficiently obtained for the portion of the pressure-sensitive adhesive layer exposed to air after the edge portion of the cleaved die bond film (adhesive layer) 3 is peeled off due to polymerization inhibition by oxygen in the ambient air. The smaller the adhesive strength A after irradiation with ultraviolet light under oxygen, the more preferable it is. However, it is difficult to completely prevent polymerization inhibition by oxygen, and there is a limit to the adhesive strength reduction. Meanwhile, in the series of processes for obtaining a semiconductor chip with a die bond film, it is naturally necessary to consider properties other than the adhesive strength A after irradiation with ultraviolet light under oxygen to the die bond film (adhesive layer) 3 of the dicing tape 10. In the adhesive layer of the present invention, the lower limit is preferably 1.25 N/25 mm. Furthermore, if the adhesive strength A after ultraviolet irradiation under oxygen exceeds 3.50 N/25 mm, during the pick-up process, after ultraviolet irradiation of the adhesive layer 2, when a pickup suction collet is brought into contact with and landed on the surface of a semiconductor chip with a die bond film on the dicing tape 10 positioned on a push-up jig from above, the edge portion of the die bond film of the semiconductor chip with a die bond film that had peeled off from the adhesive layer 2 of the dicing tape 10 becomes strongly re-adhered to the insufficiently cured adhesive layer 2 to the extent that the semiconductor chip with the die bond film cannot be easily peeled off from the adhesive layer 2 even by pushing up with the jig from the underside of the dicing tape 10 and suction and lifting with the suction collet. Even if the dicing tape 10 is pushed up from the underside using a push-up jig, it is difficult to trigger peeling from the edge portion, and pick-up of the semiconductor chip with the die bond film may be hindered. Furthermore, if the push-up height (push-up amount) of the push-up jig is increased to forcibly pick up the semiconductor chip, the risk of damaging the semiconductor chip increases. The adhesive strength A after ultraviolet irradiation under oxygen is preferably in the range of 1.30 N/25 mm or more and 3.00 N/25 mm or less, and more preferably in the range of 1.35 N/25 mm or more and 2.75 N/25 mm or less.

If the adhesive strength A after UV irradiation under oxygen is in the range of 3.50 N/25 mm or less, during the pickup process, after UV irradiation of the adhesive layer 2, when a pickup suction collet is brought into contact with and landed on the surface of a semiconductor chip with a die bond film on the dicing tape 10 positioned on a push-up jig from above, the edge of the die bond film of the semiconductor chip with a die bond film that had peeled off from the adhesive layer 2 of the dicing tape 10 is strongly re-adhered to the adhesive layer 2, which has not yet been sufficiently cured by UV irradiation. In other words, the re-adhesion strength is weakened to a level where the semiconductor chip with the die bond film can be easily peeled from the adhesive layer 2 by pushing up the dicing tape 10 from the underside with a jig. When the dicing tape 10 is pushed up from the underside with a push-up jig, peeling from the edge is easily initiated and pick-up of the semiconductor chip with the die bond film is not hindered. This also reduces the risk of damage to the semiconductor chip during pick-up. As a result, in the pick-up process, the semiconductor chip with the die bond film can be easily picked up from the adhesive layer 2 after ultraviolet irradiation.

As described above, in an actual pick-up process, when the edge portion of the die bond film of a semiconductor chip with a die bond film that has been peeled off from the pressure-sensitive adhesive layer 2 of the dicing tape 10 is re-adhered to the pressure-sensitive adhesive layer 2 that has been irradiated with ultraviolet light while exposed to air, the re-adhesion strength is weakened compared to conventional methods. It is presumed that this is due to the following reasons. That is, first, (1) the surface of the pressure-sensitive adhesive layer 2, whose adhesive strength A after ultraviolet light irradiation in the presence of oxygen has been reduced to a level of 3.50 N/25 mm or less, is cured to a desired level by ultraviolet light irradiation, and is given an appropriate hardness. The pressure-sensitive adhesive layer 2 of this embodiment has significantly reduced wettability and conformability to the die bond film 3 compared to the pressure-sensitive adhesive layer 2 before ultraviolet light irradiation and a conventional pressure-sensitive adhesive layer after ultraviolet light irradiation that is insufficiently cured due to polymerization inhibition by oxygen. On the other hand, (2) when actually picking up a semiconductor chip with a die bond film, the time from when the edge portion of the die bond film of the semiconductor chip with a die bond film that had peeled off from the pressure-sensitive adhesive layer 2 of the dicing tape 10 re-adheres to the pressure-sensitive adhesive layer 2 after ultraviolet irradiation due to contact and landing of the suction collet on the semiconductor chip until it is pushed up by a jig from the underside of the dicing tape 10 is extremely short. Therefore, even if the surface of the edge portion of the peeled die bond film (adhesive layer) re-contacts the surface of the pressure-sensitive adhesive layer 2 of this embodiment, in which the adhesive strength A after ultraviolet irradiation under oxygen is reduced to a level of 3.50 N/25 mm or less, the jig immediately begins pushing up against the semiconductor chip with the die bond film from the underside of the dicing tape 10 before the two layers have sufficiently bonded together, and the process transitions to pickup. In other words, when the semiconductor chip is re-adhered, it is possible to avoid the adhesive strength between the two layers being maintained at a high value as in the conventional method.
Therefore, when the edge portion of the die bond film of the semiconductor chip with die bond film is moderately peeled from the adhesive layer 2 by the expanding process, combined with the effect of reducing the adhesive strength A after irradiation with ultraviolet light in the presence of oxygen described above, it is believed that the force required to initially peel the edge portion of the semiconductor chip with die bond film is smaller than in the conventional pattern in which the cleaved die bond film (adhesive layer) and the adhesive layer are not peeled by the expanding process, but remain in close contact ever since the two layers are first bonded together, and are then subjected to the pick-up process.

The adhesive strength A after ultraviolet irradiation under oxygen in the present invention is measured by the method described below. First, a dicing tape 10 and a stainless steel plate (SUS304 BA plate) are separately prepared. The dicing tape 10 is cut to a size of 25 mm wide (TD direction of the base film 1) and 120 mm long (MD direction of the base film 1). Next, the release liner is peeled off from the pressure-sensitive adhesive layer 2 side of the dicing tape 10, and ultraviolet (UV) rays with a center wavelength of 367 nm are irradiated using a metal halide lamp (irradiation intensity: 70 mW/cm ² , integrated light quantity: 150 mJ/cm ² ). Then, the dicing tape 10 is neatly pressed and bonded to the stainless steel plate (SUS304 BA plate) from the edge of the pressure-sensitive adhesive layer 2 side using a 2 kg rubber roller at a temperature of 23°C and a humidity of 50% RH by moving the rubber roller back and forth once at a speed of approximately 5 mm/sec to obtain a test specimen for measurement. After leaving the test piece for 20 minutes, the adhesive strength of the test piece was measured using a peel angle adjustable adhesive/film peeling analyzer shown in Figure 4. First, a test piece for measurement, in which dicing tape 10 was bonded to stainless steel plate 4, was fixed and mounted on flat cross stage 5 for the adhesive/film peeling analyzer using a dedicated jig, and the end of dicing tape 10 was fixed to load cell 7 equipped with a gripping jig (not shown). Next, in an environment of 23°C temperature and 50% RH, as shown in Figure 4 (a schematic view of the apparatus viewed from directly above), actuator 6 moved rotating stage 8 on which flat cross stage 5 was mounted at a stage speed V1 of 300 mm/min in the direction opposite to load cell 7 (arrow V1 direction), while flat cross stage 5 was also moved on rotating stage 8 at a peel speed V2 of 300 mm/min synchronized with stage speed V1 in the direction of a peel angle of 90° (arrow V2 direction). This allows the dicing tape 10 to be peeled off from the stainless steel plate 4 fixed and mounted on a flat cross stage at a peeling rate of 300 mm/min while maintaining a peel angle of 90°. The load cell 7 detects the load when the pressure-sensitive adhesive layer 2 together with the base film 1 is peeled off from the stainless steel plate 4, and the adhesive strength is measured. Using the above method, the adhesive strength (unit: N/25 mm) of the dicing tape 10 to the stainless steel plate (SUS304 BA plate) 4 at a peel angle of 90° is measured. The measurement is performed on three test pieces, and the average of the values for the three specimens is taken as the adhesive strength A of the dicing tape 10 after irradiation with ultraviolet light in the presence of oxygen.

Furthermore, the adhesive strength B of the adhesive layer 2 of the dicing tape 10 to a stainless steel plate (SUS304 BA plate) after UV irradiation in the absence of oxygen is in the range of 0.25 N/25 mm to 0.70 N/25 mm at 23°C. Here, the adhesive strength B after UV irradiation in the absence of oxygen is the adhesive strength representing the adhesive strength of the bonded surface (the surface that is in close contact without peeling) between the adhesive layer 2 and the adherend (die bond film 3) after UV irradiation, without taking into account the effects of oxygen inhibition due to ambient oxygen. From the perspective of improving pickup performance, the smaller the adhesive strength B after UV irradiation within the above range, the better. However, if it is less than 0.25 N/25 mm, the semiconductor chip with the die bond film may unintentionally fall off or become misaligned from its fixed position on the adhesive layer 2 of the dicing tape 10 prior to pickup. Furthermore, if the adhesive strength B after irradiation with ultraviolet light in the absence of oxygen is greater than 0.70 N/25 mm, even if a push-up jig is used to push up from the underside of the dicing tape 10 in the pick-up process, peeling of the die bond film 3a from the adhesive layer 2 toward the center following peeling of the edge portion of the die bond film 3a is difficult to progress, and pick-up itself may be difficult. Furthermore, if an attempt is made to forcefully pick up the die bond film 3a by increasing the push-up height (push-up amount) of the push-up jig, the semiconductor chip may be damaged. The adhesive strength B after irradiation with ultraviolet light in the absence of oxygen is preferably in the range of 0.30 N/25 mm or more and 0.65 N/25 mm or less, and more preferably in the range of 0.35 N/25 mm or more and 0.60 N/25 mm or less.

When the adhesive strength B after irradiation with ultraviolet light in the absence of oxygen is in the range of 0.25 N/25 mm or more and 0.70 N/25 mm or less, in the pick-up step, when the dicing tape 10 is pushed up from the underside using a push-up jig, at the contact surface between the die bond film of the semiconductor chip with the die bond film and the pressure-sensitive adhesive layer 2, peeling of the die bond film from the pressure-sensitive adhesive layer 2 tends to progress from the outer periphery of the contact surface toward the center, resulting in good pick-up properties. In addition, the risk of damaging the semiconductor chip during pick-up is also reduced.

The adhesive strength B after ultraviolet irradiation in the absence of oxygen in the present invention is measured by the method described below. First, a dicing tape 10 and a stainless steel plate (SUS304 BA plate) are prepared separately. The dicing tape 10 is cut to a size of 25 mm wide (TD direction of the base film 1) and 120 mm long (MD direction of the base film 1). Next, a 2 kg rubber roller is used to press the two edges of the adhesive layer of the dicing tape 10, from which the release liner has been removed, against the stainless steel plate (SUS304 BA plate) at a temperature of 23°C and a humidity of 50% RH, at a speed of approximately 5 mm/sec. After leaving it for 20 minutes, ultraviolet (UV) rays with a center wavelength of 367 nm are irradiated from the base film 1 side of the dicing tape 10 using a metal halide lamp (irradiation intensity: 70 mW/ ^cm2 , cumulative light quantity: 150 mJ/ ^cm2 ) to prepare a test piece for measurement. The test piece is used to measure the adhesive strength (unit: N/25 mm) of the dicing tape 10 at a peel angle of 90° to a stainless steel plate (SUS304 BA plate) using a flexible peel angle type adhesive/coating peeling analyzer shown in Figure 4, in the same manner as in the measurement of adhesive strength A after ultraviolet irradiation in the presence of oxygen described above. Measurements are made for three test pieces, and the average of the values for the three specimens is taken as adhesive strength B of the dicing tape 10 after ultraviolet irradiation in the absence of oxygen.

The ratio A/B of the adhesive strength A after UV irradiation in the presence of oxygen to the adhesive strength B after UV irradiation in the absence of oxygen of the adhesive layer 2 of the dicing tape 10 can be calculated to evaluate the effect of oxygen on polymerization inhibition in the adhesive layer.

In the dicing tape 10 of this embodiment, the ratio A/B of the adhesive strength A after UV irradiation in the presence of oxygen to the adhesive strength B after UV irradiation in the absence of oxygen is not particularly limited as long as it does not impair the effects of the present invention, but is preferably in the range of 3.00 to 5.00. When the ratio A/B of the adhesive strength A after UV irradiation in the presence of oxygen to the adhesive strength B after UV irradiation in the absence of oxygen is within the above range, it becomes easier to prevent the adhesive strength of the peeled (lifted) edge portion of the cleaved die bond film (adhesive layer) 3 in the pressure-sensitive adhesive layer 2 formed by the expanding process of the dicing tape 10 from being sufficiently reduced and maintained at a high value due to polymerization inhibition by oxygen in the surrounding air when irradiated with UV light. In other words, the re-adhesion force can be weakened to a level where the dicing tape 10 can be more easily peeled by pushing up with a jig from the underside. As a result, when the dicing tape 10 is pushed up from the underside using a push-up jig, it becomes easier to initiate peeling from the edge portion, and the force required to initially peel the edge portion of the semiconductor chip with the die bond film can be reduced, making it possible to more effectively pick up the semiconductor chip with the die bond film from the adhesive layer 2 after ultraviolet irradiation.

[Thickness of adhesive layer]
The thickness of the pressure-sensitive adhesive layer 2 in this embodiment is not particularly limited, but is preferably in the range of 3 μm to 30 μm, more preferably 5 μm to 20 μm, and particularly preferably 8 μm to 15 μm. If the thickness of the pressure-sensitive adhesive layer 2 is less than 3 μm, the adhesive strength of the dicing tape 10 may be excessively reduced, especially if a large amount of polyisocyanate-based crosslinking agent is added. In this case, the adhesive strength to the SUS ring frame may be insufficient, and the dicing tape 10 may peel off from the SUS ring frame during the cool expansion process, preventing a normal expansion process. Furthermore, when used as a dicing die bond film, poor adhesion between the pressure-sensitive adhesive layer 2 and the die bond film 3 may occur. On the other hand, if the thickness of the pressure-sensitive adhesive layer 2 exceeds 30 μm, particularly if the amount of polyisocyanate-based crosslinking agent added is large, when the dicing tape 10 is cool expanded, the die bond film 3 will peel excessively from the pressure-sensitive adhesive layer 2, and sufficient external stress will not be applied to the die bond film 3 via the pressure-sensitive adhesive layer 2, which may result in the die bond film 3 not being cleaved cleanly, or the kerf width may not be sufficiently secured, or the kerf width may vary. In such cases, there is a risk of increased pickup defects of semiconductor chips with die bond films. Also, from an economical standpoint, this is not very preferable in practice.

(Anchor coat layer)
In the dicing tape 10 of this embodiment, an anchor coat layer matching the composition of the base film 1 may be provided between the base film 1 and the pressure-sensitive adhesive layer 2, depending on the manufacturing conditions of the dicing tape 10 and the use conditions of the manufactured dicing tape 10, within the scope that does not impair the effects of the present invention. By providing an anchor coat layer, the adhesion between the base film 1 and the pressure-sensitive adhesive layer 2 is improved.

(Release liner)
Furthermore, a release liner may be provided, if necessary, on the surface side (one surface side) of the pressure-sensitive adhesive layer 2 opposite to the base film 1. There are no particular limitations on the material that can be used as the release liner, and examples include synthetic resins such as polyethylene, polypropylene, and polyethylene terephthalate, as well as paper. Furthermore, the surface of the release liner may be subjected to a release treatment using a silicone-based release agent, a long-chain alkyl-based release agent, a fluorine-based release agent, or the like, in order to improve the releasability of the pressure-sensitive adhesive layer 2. There are no particular limitations on the thickness of the release liner, but a release liner in the range of 10 μm or more and 200 μm or less can be suitably used.

(Dicing tape manufacturing method)
5 is a flowchart illustrating a method for manufacturing the dicing tape 10. First, a release liner is prepared (step S101: release liner preparation step). Next, a coating solution for the adhesive layer 2 (adhesive layer-forming coating solution), which is a material for forming the adhesive layer 2, is prepared (step S102: coating solution preparation step). The coating solution can be prepared, for example, by uniformly mixing and stirring an acrylic adhesive polymer, a crosslinking agent, and a dilution solvent, which are components of the adhesive layer 2. As the solvent, for example, a general-purpose organic solvent such as toluene or ethyl acetate can be used.

The adhesive layer 2 coating solution prepared in step S102 is then applied to the release-treated surface of the release liner and dried to form an adhesive layer 2 of a predetermined thickness (step S103: adhesive layer formation step). The application method is not particularly limited, and can be performed using, for example, a die coater, a comma coater (registered trademark), a gravure coater, a roll coater, or a reverse coater. Drying conditions are also not particularly limited, but a preferred drying temperature is between 80°C and 150°C, and a drying time is between 0.5 and 5 minutes. Next, a substrate film 1 is prepared (step S104: substrate film preparation step). The substrate film 1 is then bonded to the adhesive layer 2 formed on the release liner (step S105: substrate film bonding step). Finally, the formed adhesive layer 2 is aged for 72 hours, for example, at 40°C, to crosslink and cure the acrylic adhesive polymer and the crosslinking agent by reacting them (step S106: thermal curing step). Through the above steps, dicing tape 10 can be manufactured, which comprises, from the base film side, adhesive layer 2 and release liner on base film 1. Note that in the present invention, a laminate comprising a release liner on adhesive layer 2 may also be referred to as dicing tape 10.

As a method for forming the adhesive layer 2 on the base film 1, a method in which a coating solution for the adhesive layer 2 is applied to a release liner and dried, and then the base film 1 is laminated onto the adhesive layer 2 has been exemplified. However, a method in which a coating solution for the adhesive layer 2 is directly applied to the base film 1 and dried may also be used. From the perspective of stable production, the former method is preferably used.

The dicing tape 10 of this embodiment may be in the form of a roll or a stack of wide sheets. It may also be in the form of a sheet or tape formed by cutting the dicing tape 10 in these forms to a predetermined size.

<Dicing die bond film>
The dicing tape 10 of this embodiment can also be used in the semiconductor manufacturing process in the form of a dicing die bond film 20 in which a die bond film (adhesive layer) 3 is releasably adhered and laminated on the pressure-sensitive adhesive layer 2 of the dicing tape 10. The die bond film (adhesive layer) 3 is used to adhere and connect singulated semiconductor chips to a lead frame or a wiring substrate (support substrate). When semiconductor chips are stacked, it also serves as an adhesive layer between the semiconductor chips. In this case, the first-layer semiconductor chip is adhered to a semiconductor chip-mounting wiring substrate on which terminals are formed by the die bond film (adhesive layer) 3, and the second-layer semiconductor chip is further adhered to the first-layer semiconductor chip by the die bond film (adhesive layer) 3. The connection terminals of the first-layer semiconductor chip and the second-layer semiconductor chip are electrically connected to external connection terminals via wires, but the wires for the first-layer semiconductor chip are embedded in the die bond film (adhesive layer) 3, i.e., the wire-embedded die bond film (adhesive layer) 3, during pressure bonding (die bonding). Hereinafter, an example of the die bond film (adhesive layer) 3 when the dicing tape 10 of this embodiment is used in the form of a dicing die bond film 20 will be shown, but the present invention is not particularly limited to this example.

(Die bond film)
The die bond film (adhesive layer) 3 is a layer made of a thermosetting adhesive composition that hardens when heated. The adhesive composition is not particularly limited, and conventionally known materials can be used. A preferred example of the adhesive composition is a thermosetting adhesive composition obtained by adding a curing accelerator, an inorganic filler, a silane coupling agent, etc. to a resin composition containing a glycidyl group-containing (meth)acrylic acid ester copolymer as a thermoplastic resin, an epoxy resin as a thermosetting resin, and a phenolic resin as a curing agent for the epoxy resin. A die bond film (adhesive layer) 3 made of such a thermosetting adhesive composition is preferable because it has excellent adhesion between a semiconductor chip and a support substrate and between semiconductor chips, can also be provided with electrode embeddability and/or wire embeddability, can be bonded at low temperatures during the die bonding process, can be cured well in a short time, and has excellent reliability after molding with a sealant.

General-purpose die bond films, in which the wires are not embedded in the adhesive layer, and wire-embedded die bond films, in which the wires are embedded in the adhesive layer, often use roughly the same types of materials that make up their adhesive compositions. However, by changing the blending ratio of the materials used and the physical properties and characteristics of each material according to the respective purposes, they can be customized for either general-purpose or wire-embedded die bond films. Furthermore, if there are no problems with the reliability of the final semiconductor device, wire-embedded die bond films may also be used as general-purpose die bond films. In other words, wire-embedded die bond films are not limited to wire-embedding applications, and can similarly be used for bonding semiconductor chips to substrates with unevenness due to wiring, metal substrates such as lead frames, etc.

(Adhesive composition for general-purpose die-bonding films)
First, an example of an adhesive composition for a general-purpose die-bonding film will be described, but the invention is not particularly limited to this example. As an index of the fluidity of the die-bonding film 3 formed from the adhesive composition during die-bonding, for example, the shear viscosity characteristic at 80°C can be mentioned, and in the case of a general-purpose die-bonding film, the shear viscosity at 80°C generally shows a value in the range of 20,000 Pa s or more and 40,000 Pa s or less, preferably 25,000 Pa s or more and 35,000 Pa s or less. An example of a preferred embodiment of the adhesive composition for general-purpose die-bonding films is an adhesive composition that contains, when the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenol resin, which are resin components of the adhesive composition, is taken as 100 parts by mass, (a) the glycidyl group-containing (meth)acrylic acid ester copolymer is contained in a range of 52 parts by mass or more and 90 parts by mass or less, the epoxy resin is contained in a range of 5 parts by mass or more and 25 parts by mass or less, and the phenol resin is contained in a range of 5 parts by mass or more and 23 parts by mass or less, so that the total amount of the resin components is 100 parts by mass, (b) a curing accelerator is contained in a range of 0.1 parts by mass or more and 0.3 parts by mass or less, relative to 100 parts by mass of the total amount of the epoxy resin and the phenol resin, and (c) an inorganic filler is contained in a range of 5 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenol resin.

[Glycidyl group-containing (meth)acrylic acid ester copolymer]
The glycidyl group-containing (meth)acrylic acid ester copolymer preferably contains, as copolymer units, at least a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and glycidyl (meth)acrylate. From the viewpoint of ensuring appropriate adhesive strength, the glycidyl (meth)acrylate copolymer unit is preferably contained in a range of 0.5% by mass to 6.0% by mass, more preferably 2.0% by mass to 4.0% by mass, of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer. Furthermore, the glycidyl group-containing (meth)acrylic acid ester copolymer may contain other monomers such as styrene or acrylonitrile as copolymer units, as necessary, from the viewpoint of adjusting the glass transition temperature (Tg).

The glass transition temperature (Tg) of the above-mentioned glycidyl group-containing (meth)acrylic acid ester copolymer is preferably in the range of -50°C or higher and 30°C or lower, and from the viewpoint of improving handleability as a die-bonding film (suppressing tackiness), it is more preferably in the range of -10°C or higher and 30°C or lower. To achieve such a glass transition temperature for the glycidyl group-containing (meth)acrylic acid ester copolymer, it is preferable to use ethyl (meth)acrylate and/or butyl (meth)acrylate as the above-mentioned (meth)acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms.

The weight-average molecular weight Mw of the glycidyl group-containing (meth)acrylic acid ester copolymer is preferably in the range of 500,000 to 2,000,000, and more preferably in the range of 700,000 to 1,000,000. When the weight-average molecular weight Mw is within the above range, it is easy to achieve appropriate adhesive strength, heat resistance, and flow properties. Here, the weight-average molecular weight Mw refers to the value measured by gel permeation chromatography in terms of standard polystyrene.

The content of the glycidyl group-containing (meth)acrylic acid ester copolymer in the die bond film (adhesive layer) 3 is preferably in the range of 52% by mass or more and 90% by mass or less, and more preferably in the range of 60% by mass or more and 80% by mass or less, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, which are resin components in the adhesive composition, and the epoxy resin and phenolic resin described below.

[Epoxy resin]
The epoxy resin is not particularly limited, but examples thereof include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, alicyclic epoxy resins, aliphatic linear epoxy resins, phenol novolac epoxy resins, alkylphenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, diglycidyl ethers of biphenols, diglycidyl ethers of naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and difunctional epoxy resins and novolac epoxy resins such as alkyl-substituted, halide, and hydrogenated versions of these. Other commonly known epoxy resins, such as multifunctional epoxy resins and heterocycle-containing epoxy resins, may also be used. These may be used alone or in combination of two or more.

From the viewpoint of adhesive strength and heat resistance, the softening point of the above epoxy resin is preferably in the range of 70°C or higher and 130°C or lower. Furthermore, from the viewpoint of sufficiently promoting the curing reaction with the phenolic resin described below, the epoxy equivalent of the above epoxy resin is preferably in the range of 100 or higher and 300 or lower.

From the perspective of allowing the die bond film (adhesive layer) 3 to properly exhibit its function as a thermosetting adhesive, the content of the epoxy resin in the die bond film (adhesive layer) 3 is preferably in the range of 5% by mass or more and 25% by mass or less, and more preferably in the range of 10% by mass or more and 20% by mass or less, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenolic resin described below, which are resin components in the adhesive composition.

[Phenol resin: hardener for epoxy resin]
The curing agent for the epoxy resin is not particularly limited, but examples thereof include phenolic resins that can be obtained by reacting a phenolic compound with a xylylene compound, which is a divalent linking group, in the absence or presence of an acid catalyst. Examples of the phenolic resins include novolac-type phenolic resins, resol-type phenolic resins, and polyoxystyrenes such as polyparaoxystyrene. Examples of novolac-type phenolic resins include phenol novolac resins, phenol aralkyl resins, cresol novolac resins, tert-butylphenol novolac resins, and nonylphenol novolac resins. These phenolic resins may be used alone or in combination of two or more. Among these phenolic resins, phenol novolac resins and phenol aralkyl resins tend to improve the connection reliability of the die-bonding film (adhesive layer) 3, and are therefore preferably used.

From the viewpoint of adhesive strength and heat resistance, the softening point of the phenolic resin is preferably in the range of 70°C or higher and 90°C or lower. Furthermore, from the viewpoint of sufficiently promoting the curing reaction with the epoxy resin, the hydroxyl group equivalent of the phenolic resin is preferably in the range of 100 or higher and 200 or lower.

From the perspective of ensuring sufficient progress in the curing reaction between the epoxy resin and the phenolic resin in the thermosetting resin composition, the phenolic resin is preferably blended in an amount such that the hydroxyl group content in all phenolic resin components is preferably in the range of 0.5 to 2.0 equivalents, more preferably 0.8 to 1.2 equivalents, per equivalent of epoxy groups in all epoxy resin components. While this cannot be generalized as it depends on the functional group equivalent of each resin, for example, the content of the phenolic resin is preferably in the range of 5 to 23% by mass, where the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenolic resin, which are the resin components in the adhesive composition, is taken as 100 parts by mass.

[Curing accelerator]
Furthermore, if necessary, a curing accelerator such as a tertiary amine, imidazole, or quaternary ammonium salt can be added to the thermosetting resin composition. Specific examples of such curing accelerators include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-cyanoethyl-2-phenylimidazolium trimellitate. These may be used alone or in combination of two or more. The amount of the curing accelerator added is preferably in the range of 0.1 to 0.3 parts by mass per 100 parts by mass of the epoxy resin and the phenolic resin combined.

[Inorganic filler]
Furthermore, an inorganic filler can be added to the thermosetting resin composition as needed to control the fluidity of the die bond film (adhesive layer) 3 and improve its elastic modulus. Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whisker, boron nitride, crystalline silica, and amorphous silica. These fillers can be used alone or in combination of two or more. Among these, crystalline silica and amorphous silica are preferred for versatility. Specifically, Aerosil (registered trademark: ultrafine particle dry silica), which has a nano-sized average particle size, is preferred. The content of the inorganic filler in the die bond film (adhesive layer) 3 is preferably in the range of 5% by mass to 20% by mass, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, epoxy resin, and phenolic resin, which are the resin components.

[Silane coupling agent]
Furthermore, a silane coupling agent can be added to the thermosetting resin composition as needed to improve adhesion to the adherend. Examples of silane coupling agents include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane, and these can be used alone or in combination of two or more. The amount of the silane coupling agent added is preferably in the range of 1.0 to 7.0 parts by mass per 100 parts by mass of the epoxy resin and the phenolic resin combined.

[others]
Furthermore, the thermosetting resin composition may contain a flame retardant, an ion trapping agent, etc., as long as the function of the die bond film is not impaired. Examples of flame retardants include antimony trioxide, antimony pentoxide, and brominated epoxy resins. Examples of ion trapping agents include hydrotalcites, bismuth hydroxide, hydrous antimony oxide, zirconium phosphate with a specific structure, magnesium silicate, aluminum silicate, triazole-based compounds, tetrazole-based compounds, and bipyridyl-based compounds.

(Adhesive composition for wire-embedded die-bonding film)
Next, an example of an adhesive composition for a wire-embedded die bond film will be described, but the invention is not particularly limited to this example. As an index of the fluidity of the die bond film 3 formed from the adhesive composition during die bonding, for example, the shear viscosity characteristic at 80°C can be mentioned. In the case of a wire-embedded die bond film, the shear viscosity at 80°C generally shows a value in the range of 200 Pa s to 11,000 Pa s, preferably in the range of 2,000 Pa s to 7,000 Pa s. An example of a preferred embodiment of the adhesive composition for a wire-embedded die-bonding film includes an adhesive composition that contains, when the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenol resin, which are resin components of the adhesive composition, is taken as 100 parts by mass, (a) the glycidyl group-containing (meth)acrylic acid ester copolymer is contained in a range of 17 parts by mass to 51 parts by mass, the epoxy resin is contained in a range of 30 parts by mass to 64 parts by mass, and the phenol resin is contained in a range of 19 parts by mass to 53 parts by mass, with the total amount of the resin components being adjusted to 100 parts by mass; (b) a curing accelerator is contained in a range of 0.01 parts by mass to 0.07 parts by mass relative to 100 parts by mass of the total amount of the epoxy resin and the phenol resin; and (c) an inorganic filler is contained in a range of 10 parts by mass to 80 parts by mass relative to 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenol resin.

[Glycidyl group-containing (meth)acrylic acid ester copolymer]
The glycidyl group-containing (meth)acrylic acid ester copolymer preferably contains, as copolymer units, at least a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 8 carbon atoms and glycidyl (meth)acrylate. In the case of a wire-embedded die-bonding film, it is necessary to achieve both improved fluidity during die bonding and ensure adhesive strength after curing. Therefore, it is preferable to use a glycidyl group-containing (meth)acrylic acid ester copolymer (A) having a high copolymer unit ratio of glycidyl (meth)acrylate and a low molecular weight in combination with a glycidyl group-containing (meth)acrylic acid ester copolymer (B) having a low copolymer unit ratio of glycidyl (meth)acrylate and a high molecular weight in combination, and it is preferable that the former (A) component of the combination is contained in a certain amount or more.

Specifically, the glycidyl group-containing (meth)acrylic acid ester copolymer in the adhesive composition for wire-embedded die bond films preferably comprises a mixture of "glycidyl group-containing (meth)acrylic acid ester copolymer (A) containing glycidyl (meth)acrylate copolymer units in a range of 5.0% by mass to 15.0% by mass, based on the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, having a glass transition temperature (Tg) in the range of -50°C to 30°C, and a weight average molecular weight Mw in the range of 100,000 to 400,000" and "glycidyl group-containing (meth)acrylic acid ester copolymer (B) containing glycidyl (meth)acrylate copolymer units in a range of 1.0% by mass to 7.0% by mass, based on the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, having a glass transition temperature (Tg) in the range of -50°C to 30°C, and a weight average molecular weight Mw in the range of 500,000 to 900,000." Here, the weight average molecular weight Mw refers to the value measured by gel permeation chromatography in terms of standard polystyrene.

The content of the glycidyl group-containing (meth)acrylic acid ester copolymer (A) is preferably in the range of 60% by mass or more and 90% by mass or less of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer (the sum of (A) and (B)). Furthermore, the glycidyl group-containing (meth)acrylic acid ester copolymer may contain other monomers, such as styrene or acrylonitrile, as copolymer units, as necessary, in order to adjust the glass transition temperature (Tg).

The glass transition temperature (Tg) of the entire glycidyl group-containing (meth)acrylic acid ester copolymer is preferably in the range of -50°C or higher and 30°C or lower, and from the viewpoint of improving handleability as a die-bonding film (reducing tackiness), it is more preferably in the range of -10°C or higher and 30°C or lower. To achieve such a glass transition temperature for the glycidyl group-containing (meth)acrylic acid ester copolymer, it is preferable to use ethyl (meth)acrylate and/or butyl (meth)acrylate as the (meth)acrylic acid alkyl ester having an alkyl group with 1 to 8 carbon atoms.

From the viewpoint of fluidity during die bonding and adhesive strength after curing, the content of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer (the sum of (A) and (B)) in the wire-embedded die bond film (adhesive layer) 3 is preferably in the range of 17% by mass or more and 51% by mass or less, and more preferably in the range of 20% by mass or more and 45% by mass or less, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin and the phenolic resin described below, which are the resin components in the adhesive composition.

[Epoxy resin]
The epoxy resin is not particularly limited, but the same as the epoxy resin exemplified for the adhesive composition for the general-purpose die-bonding film described above can be used. These may be used alone or in combination of two or more kinds, but in the case of a wire-embedded die-bonding film, it is necessary to ensure adhesive strength and to impart good wire embeddability while suppressing the occurrence of voids on the adhesive surface, so it is preferable to use two or more kinds of epoxy resins in combination in order to control the fluidity and elastic modulus.

A preferred embodiment of the epoxy resin used in the wire-embedded die bond film (adhesive layer) 3 is a mixture of an epoxy resin (C) that is liquid at room temperature and an epoxy resin (D) that has a softening point of 98°C or less, preferably 85°C or less. The content of the epoxy resin (C) that is liquid at room temperature is preferably in the range of 15% to 75% by mass, and more preferably in the range of 30% to 50% by mass, of the total amount of epoxy resin (total of (C) and (D)). The epoxy equivalent of the epoxy resin is preferably in the range of 100 to 300, from the viewpoint of sufficiently promoting the curing reaction with the phenolic resin described below.

From the perspective of ensuring that the die bond film (adhesive layer) 3 properly exhibits its function as a thermosetting adhesive, the content of the epoxy resin in the die bond film (adhesive layer) 3 is preferably in the range of 30% by mass or more and 64% by mass or less, and more preferably in the range of 35% by mass or more and 50% by mass or less, where the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenolic resin described below, which are resin components in the adhesive composition, is taken as 100 parts by mass.

[Phenol resin: hardener for epoxy resin]
The curing agent for the epoxy resin is not particularly limited, but the same curing agents as those exemplified as the phenolic resin for the adhesive composition for general-purpose die-bonding films described above can be used in the same manner. From the viewpoints of adhesive strength and fluidity, the softening point of the phenolic resin is preferably in the range of 70°C or higher and 115°C or lower. Furthermore, from the viewpoint of sufficiently progressing the curing reaction with the epoxy resin, the hydroxyl group equivalent of the phenolic resin is preferably in the range of 100 or higher and 200 or lower.

From the viewpoint of sufficiently promoting the curing reaction between the epoxy resin and the phenolic resin in the thermosetting resin composition, the phenolic resin is preferably blended in an amount such that the hydroxyl group content in all phenolic resin components is preferably in the range of 0.5 to 2.0 equivalents per equivalent of epoxy groups in all epoxy resin components; from the viewpoint of achieving compatibility with fluidity during die bonding, it is more preferable to blend in an amount such that the hydroxyl group content in all phenolic resin components is in the range of 0.6 to 1.0 equivalents per equivalent of epoxy groups in all epoxy resin components. While this cannot be generalized as it depends on the functional group equivalent of each resin, for example, the content of the phenolic resin is preferably in the range of 19 to 53% by mass, where the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, the epoxy resin, and the phenolic resin, which are the resin components in the adhesive composition, is taken as 100 parts by mass.

[Curing accelerator]
Furthermore, if necessary, a curing accelerator such as a tertiary amine, imidazole, or quaternary ammonium salt can be added to the thermosetting resin composition. As such a curing accelerator, the same ones as those exemplified as curing accelerators for the adhesive composition for a general-purpose die-bonding film can be used. From the viewpoint of suppressing the occurrence of voids at the bonding surface, the amount of the curing accelerator added is preferably in the range of 0.01 parts by mass or more and 0.07 parts by mass or less per 100 parts by mass of the epoxy resin and the phenolic resin combined.

[Inorganic filler]
Furthermore, an inorganic filler can be added to the thermosetting resin composition as needed from the viewpoints of improving the handleability of the die bond film (adhesive layer) 3, adjusting the fluidity during die bonding, imparting thixotropy, improving adhesive strength, etc. As the inorganic filler, the same inorganic fillers as those exemplified as the inorganic fillers for the adhesive composition for a general-purpose die bond film described above can be used, but among these, silica filler is preferably used from the viewpoint of versatility. The content ratio of the inorganic filler in the die bond film (adhesive layer) 3 is preferably in the range of 10% by mass or more and 80% by mass or less, and more preferably in the range of 15% by mass or more and 50% by mass or less, based on 100 parts by mass of the total amount of the glycidyl group-containing (meth)acrylic acid ester copolymer, epoxy resin, and phenolic resin, which are the resin components described above, from the viewpoints of fluidity during die bonding, cleavability during cool expansion, and adhesive strength.

The above-mentioned inorganic filler is preferably a mixture of two or more types of inorganic fillers with different average particle sizes, with the aim of improving the cleavability of the die bond film (adhesive layer) 3 during cool expansion and ensuring sufficient adhesive strength after curing. Specifically, it is preferable to use an inorganic filler with an average particle size in the range of 0.1 μm to 5 μm as the main inorganic filler component, accounting for 80 mass% or more based on the total mass of the inorganic filler. When it is necessary to suppress foaming of the die bond film 3 during the semiconductor chip manufacturing process, which would otherwise occur due to excessively high fluidity of the die bond film (adhesive layer) 3, or to improve adhesive strength after curing, an inorganic filler with an average particle size of less than 0.1 μm may be used in combination with the above-mentioned main inorganic filler component in a blending amount of 20 mass% based on the total mass of the inorganic filler.

[Silane coupling agent]
Furthermore, a silane coupling agent can be added to the thermosetting resin composition as needed to improve the adhesive strength to the adherend. As the silane coupling agent, the same silane coupling agents as those exemplified as the silane coupling agents for the adhesive composition for general-purpose die-bonding films can be used. From the viewpoint of suppressing the generation of voids on the adhesive surface, the amount of the silane coupling agent added is preferably in the range of 0.5 parts by mass or more to 2.0 parts by mass or less per 100 parts by mass of the epoxy resin and the phenolic resin combined.

[others]
Furthermore, a flame retardant, an ion trapping agent, or the like may be added to the thermosetting resin composition within a range that does not impair the function as the die bond film 3. As these flame retardants and ion trapping agents, the same ones as those exemplified as the flame retardants and ion trapping agents for the adhesive composition for the general-purpose die bond film described above can be used in the same manner.

(Thickness of die bond film (adhesive layer))
The thickness of the die bond film (adhesive layer) 3 is not particularly limited, but is preferably in the range of 5 μm to 200 μm in order to ensure adhesive strength, properly embed wires for connecting semiconductor chips, or sufficiently fill irregularities in wiring circuits on a substrate. If the thickness of the die bond film (adhesive layer) 3 is less than 5 μm, the adhesive strength between the semiconductor chip and the lead frame or wiring substrate may be insufficient. On the other hand, if the thickness of the die bond film (adhesive layer) 3 is greater than 200 μm, it becomes uneconomical and is likely to be insufficient in responding to the miniaturization and thinning of semiconductor devices. In terms of high adhesiveness and the ability to thin semiconductor devices, the thickness of the film-like adhesive is more preferably in the range of 10 μm to 100 μm, and particularly preferably in the range of 20 μm to 75 μm.

More specifically, when used as a general-purpose die bond film (adhesive layer), the thickness is preferably, for example, in the range of 5 μm or more and less than 30 μm, and particularly preferably in the range of 10 μm or more and 25 μm or less. When used as a wire-embedded die bond film (adhesive layer), the thickness is preferably, for example, in the range of 30 μm or more and 100 μm or less, and particularly preferably in the range of 40 μm or more and 80 μm or less.

(Method for manufacturing die bond film)
The die bond film (adhesive layer) 3 is manufactured, for example, as follows. First, a release liner is prepared. The release liner can be the same as the release liner placed on the pressure-sensitive adhesive layer 2 of the dicing tape 10. Next, a coating solution for the die bond film (adhesive layer) 3, which is the material for forming the die bond film (adhesive layer) 3, is prepared. The coating solution can be prepared, for example, by uniformly mixing and dispersing a thermosetting resin composition containing the above-mentioned components of the die bond film (adhesive layer) 3, such as a glycidyl group-containing (meth)acrylic acid ester copolymer, an epoxy resin, a curing agent for the epoxy resin, an inorganic filler, a curing accelerator, and silane coupling agent, with a dilution solvent. As the solvent, for example, a general-purpose organic solvent such as methyl ethyl ketone or cyclohexanone can be used.

Next, the coating solution for the die bond film (adhesive layer) 3 is applied to the release-treated surface of the release liner, which serves as a temporary support, and dried to form a die bond film (adhesive layer) 3 of a predetermined thickness. Then, the release-treated surface of another release liner is laminated onto the die bond film (adhesive layer) 3. The coating method is not particularly limited, and can be applied using, for example, a die coater, Comma Coater (registered trademark), gravure coater, roll coater, reverse coater, etc. Furthermore, preferred drying conditions include a drying temperature in the range of 60°C to 200°C and a drying time in the range of 1 minute to 90 minutes. In the present invention, a laminate having release liners on both or one side of the die bond film (adhesive layer) 3 may also be referred to as a die bond film (adhesive layer) 3.

(Method for manufacturing dicing die bond film)
The manufacturing method of the dicing die bond film 20 is not particularly limited, and it can be manufactured by a conventionally known method. For example, the dicing die bond film 20 can be manufactured by first preparing the dicing tape 10 and the die bond film 3 separately, then peeling off the release liners of the pressure-sensitive adhesive layer 2 of the dicing tape 10 and the die bond film (adhesive layer) 3, and then laminating the pressure-sensitive adhesive layer 2 of the dicing tape 10 and the die bond film (adhesive layer) 3 together by pressure bonding using a pressure roll such as a hot roll laminator. The lamination temperature is not particularly limited, and is preferably in the range of, for example, 10°C to 100°C, and the lamination pressure (linear pressure) is preferably in the range of, for example, 0.1 kgf/cm to 100 kgf/cm. In the present invention, the dicing die bond film 20 may also refer to a laminate in which release liners are provided on the pressure-sensitive adhesive layer 2 and the die bond film (adhesive layer) 3. In the dicing die bond film 20, the release liners provided on the pressure-sensitive adhesive layer 2 and the die bond film (adhesive layer) 3 may be peeled off when the dicing die bond film 20 is used as a workpiece.

The dicing die bond film 20 may be in the form of a roll or a laminate of wide sheets. It may also be in the form of a sheet or tape formed by cutting the dicing tape 10 in these forms to a predetermined size.

For example, as disclosed in Japanese Patent Application Laid-Open No. 2011-159929, a film roll can be manufactured by forming a large number of islands of an adhesive layer (die bond film 3) and a pressure-sensitive adhesive film (dicing tape 10) precut into the shape of a wafer constituting a semiconductor device on a release substrate (release liner). In this case, the dicing tape 10 is formed into a circular shape with a larger diameter than the die bond film (adhesive layer) 3, which in turn is formed into a circular shape with a larger diameter than the semiconductor wafer 30. When precutting into such a film roll, the dicing tape 10 may be locally heated and/or cooled to continuously and effectively peel and remove excess dicing tape 10 without tearing. The heating temperature is selected as appropriate, but is preferably in the range of 30°C to 120°C. The heating time is selected as appropriate, but is preferably in the range of 0.1 seconds to 10 seconds. The dicing tape 10 of the present invention has a certain degree of heat resistance, so even if it is subjected to heat treatment at a high temperature of 120°C, there will be no particular problems in handling it.

<Method of manufacturing semiconductor chips>
FIG. 6 is a flowchart illustrating a method for manufacturing a semiconductor chip with a die bond film using a dicing die bond film 20 in which a die bond film (adhesive layer) 3 is laminated on the pressure-sensitive adhesive layer 2 of the dicing tape 10 of this embodiment. FIG. 7 is a schematic diagram illustrating a state in which a ring frame (wafer ring) 40 is attached to the outer edge portion (exposed portion of the pressure-sensitive adhesive layer 2) of the dicing die bond film 20, and individualized semiconductor wafers (multiple semiconductor chips) are attached to the central die bond film (adhesive layer) 3. Furthermore, FIGS. 8(a) to 8(f) are cross-sectional views illustrating an example of a grinding process for a semiconductor wafer in which multiple modified regions have been formed by laser light irradiation, and a process of bonding multiple cleaved semiconductor wafers (multiple semiconductor chips) to a dicing die bond film 20. FIGS. 9(a) to 9(f) are cross-sectional views illustrating an example of a manufacturing method including a series of steps from expanding to picking up to obtain individual semiconductor chips with die bond film from multiple cleaved thin-film semiconductor wafers bonded and held on the dicing die bond film 20.

(Method for manufacturing a semiconductor chip using a dicing die bond film 20)
The method for manufacturing a semiconductor chip using the dicing die bond film 20 is not particularly limited and may be any conventionally known method, but here, a manufacturing method using SDBG (Stealth Dicing Before Griding) will be described as an example.

First, as shown in FIG. 8(a), a semiconductor wafer W is prepared, for example, a semiconductor wafer W made primarily of silicon, with multiple integrated circuits (not shown) mounted on its first surface Wa (step S201: preparation step in FIG. 6). Then, a wafer processing tape (backgrinding tape) T having an adhesive surface Ta is attached to the first surface Wa of the semiconductor wafer W.

Next, as shown in FIG. 8(b), with the semiconductor wafer W held by the wafer processing tape T, laser light focused on the interior of the wafer is irradiated onto the semiconductor wafer W from the side opposite the wafer processing tape T, i.e., the second surface Wb side of the semiconductor wafer, along the grid-like dicing lines X. Modified regions 30b are formed in the semiconductor wafer W by ablation due to multiphoton absorption (step S202: modified region formation process in FIG. 6). The modified regions 30b are weakened regions that allow the semiconductor wafer W to be cleaved and separated into semiconductor chips in a grinding process. For methods of forming modified regions 30b along the dicing lines by irradiating the semiconductor wafer W with laser light, see, for example, the methods disclosed in Japanese Patent No. 3408805, Japanese Patent Laid-Open No. 2002-192370, and Japanese Patent Laid-Open No. 2003-338567.

Next, as shown in FIG. 8(c), while the semiconductor wafer W is held on the wafer processing tape T, the semiconductor wafer W is thinned by grinding from the second surface Wb until it reaches a predetermined thickness. Here, the thickness of the semiconductor wafer 30 to be thinned is preferably adjusted to 100 μm, more preferably 10 μm to 50 μm, from the perspective of thinning the semiconductor device. In this grinding/thinning process, when the grinding load of the grinding wheel is applied to the thinned semiconductor wafer 30, cracks grow vertically from the modified region 30b formed in FIG. 8(b) as the starting point. The thinned semiconductor wafer 30 is then cleaved and singulated into multiple semiconductor chips 30a on the wafer processing tape T along cleaving lines 30c corresponding to the planned dicing lines X.

Next, as shown in FIGS. 8(d) and (e), the multiple semiconductor chips 30a held on the wafer processing tape T are bonded to the die bond film 3 of the separately prepared dicing die bond film 20 (step S204: lamination process in FIG. 6). In this process, after the release liners are peeled from the adhesive layer 2 and die bond film (adhesive layer) 3 of the circularly cut dicing die bond film 20, as shown in FIG. 7, a ring frame (wafer ring) 40 is attached to the outer edge of the dicing tape 10 (exposed portion of the adhesive layer 2) of the dicing die bond film 20, and the multiple semiconductor chips 30a held on the wafer processing tape T are attached to the die bond film (adhesive layer) 3 laminated on the upper center of the adhesive layer 2 of the dicing tape 10. Thereafter, as shown in FIG. 8(f), the wafer processing tape T is peeled off from the multiple thin-film semiconductor chips 30a. The attachment is performed while applying pressure using a pressure means such as a pressure roller. The application temperature is not particularly limited, but is preferably in the range of 20°C to 130°C, and from the perspective of reducing warpage of the semiconductor chip 30a, more preferably in the range of 40°C to 100°C. The application pressure is not particularly limited, but is preferably in the range of 0.1 MPa to 10.0 MPa. Because the dicing tape 10 of the present invention has a certain degree of heat resistance, there are no particular problems with handling even when the application temperature is high.

Next, a ring frame 40 is attached to the adhesive layer 2 of the dicing tape 10 on the dicing die bond film 20, and then, as shown in FIG. 9(a), the dicing die bond film 20 with multiple semiconductor chips 30a is fixed to a holder 41 of an expanding device. As shown in FIG. 9(b), the thin-film semiconductor wafer 30 (multiple semiconductor chips 30a) cleaved along the cleaving line 30c has a die bond film 3 attached to its underside, which will be cleaved along the planned dicing line X in the next process, so that it can be separated into multiple semiconductor chips 30a with die bond film.

Next, a first expanding process, i.e., a cool expanding process, is performed under relatively low temperatures (e.g., -30°C to 0°C) as shown in FIG. 9(c). The die bond film (adhesive layer) 3 of the dicing die bond film 20 is cleaved into small pieces of die bond film (adhesive layer) 3a corresponding to the size of the semiconductor chip 30a, thereby obtaining semiconductor chips 30a with die bond film 3a attached (step S205: cool expanding process in FIG. 6). In this process, a hollow cylindrical push-up member (not shown) provided in the expanding device abuts against the dicing tape 10 below the dicing die bond film 20 and is raised. The dicing tape 10 of the dicing die bond film 20 to which the singulated semiconductor wafer 30 (multiple semiconductor chips 30a) is bonded is expanded so as to be stretched in two dimensions, including the radial and circumferential directions of the semiconductor wafer 30. The internal stress generated by the tensile force applied to the dicing tape 10 in all directions by cool expanding is transmitted as external stress to the die bond film 3 attached to the individual semiconductor wafer 30 (plurality of semiconductor chips 30a). This external stress causes the die bond film 3, which has been embrittled at low temperature, to be cleaved into small pieces of die bond film 3a the same size as the semiconductor chips 30a, thereby obtaining semiconductor chips 30a with die bond film 3a attached.

The temperature conditions in the cool expansion process are, for example, -30°C or higher and 0°C or lower, preferably -20°C or higher and -5°C or lower, more preferably -15°C or higher and -5°C or lower, and particularly preferably -15°C. The expansion speed in the cool expansion process (the speed at which the hollow cylindrical push-up member rises) is preferably 0.1 mm/sec or higher and 1000 mm/sec or lower, more preferably 10 mm/sec or higher and 300 mm/sec or lower. Furthermore, the expansion amount in the cool expansion process (the push-up height of the hollow cylindrical push-up member) is preferably 3 mm or higher and 16 mm or lower.

Here, in the dicing tape 10 of the present invention, the average value (Y _MD +Y _TD )/2 of the elastic modulus at 5% elongation at 0°C of the base film 1 is adjusted to an appropriate range of 165 MPa or more and 260 MPa or less, so that the internal stress generated by cool expanding the dicing tape 10 in all directions is efficiently transmitted as external stress to the die bond film 3 that is in close contact with the pressure-sensitive adhesive layer 2 containing a specific active energy ray-curable pressure-sensitive adhesive composition, and as a result, the die bond film 3 is cleaved cleanly with a good yield. Furthermore, in the dicing tape 10 of the present invention, the pressure-sensitive adhesive layer 2 is composed of a pressure-sensitive adhesive composition mainly composed of an acrylic pressure-sensitive adhesive polymer having a specific hydroxyl value and a specific amount of a polyisocyanate crosslinking agent, and the equivalent ratio (-NCO)/(-OH) of the isocyanate group (-NCO) of the polyisocyanate crosslinking agent to the hydroxyl value (-OH) of the acrylic pressure-sensitive adhesive polymer is controlled to be 0.14 or more and 1.32 or less. Therefore, the pressure-sensitive adhesive layer 2 after the crosslinking reaction is given a hardness that can transmit a moderate impact to the interface between the edge part of the die-bonding film and the pressure-sensitive adhesive layer 2 immediately therebelow at the moment the die-bonding film 3 is cleaved, and a cohesive force that can transmit a stress in a direction away from the die-bonding film 3, and also a moderate initial adhesive force to the die-bonding film 3 is given. As a result, in the small piece of die bond film 3a (adhesive layer) that holds the semiconductor chip 30a and that has been cleaved by cool expanding, moderate peeling of the edge portion (four-sided peripheral portion) from the pressure-sensitive adhesive layer 2 of the dicing tape 10 is promoted, and a state in which the die bond film 3a is partially peeled from the pressure-sensitive adhesive layer 2 of the dicing tape 10 is moderately formed. Furthermore, in this case, the stress applied to the die bond film 3 and the pressure-sensitive adhesive layer 2, and the initial adhesion force to the die bond film 3 are moderately suppressed, so the cleaved die bond film does not peel excessively from the pressure-sensitive adhesive layer 2, a sufficient kerf width can be secured, and damage due to collision between semiconductor chips and displacement from the fixed position on the pressure-sensitive adhesive layer 2 can also be avoided.

In Figure 9(c), for convenience, the edge portion of the die bond film 3a (adhesive layer) of the small piece holding the semiconductor chip 30a is shown as being in close contact with the pressure-sensitive adhesive layer 2 of the dicing tape 10. However, in reality, as shown in the enlarged cross-sectional view of Figure 10, the edge portion of the die bond film 3a (adhesive layer) of the small piece holding the semiconductor chip 30a is moderately peeled off from the pressure-sensitive adhesive layer 2 of the dicing tape 10, and the center portion of the die bond film 3a (adhesive layer) is in close contact with the pressure-sensitive adhesive layer 2 of the dicing tape 10.

After the cool expansion process, the hollow cylindrical push-up member of the expansion device is lowered, releasing the expanded state of the dicing tape 10.

Next, a second expansion process, i.e., a room-temperature expansion process, is performed under relatively high-temperature conditions (e.g., 10°C to 30°C) as shown in Figure 9(d), to widen the distance (kerf width) between the semiconductor chips 30a with the die bond film (adhesive layer) 3a. In this process, a cylindrical table (not shown) provided by the expansion device is raised while abutting against the dicing tape 10 below the dicing die bond film 20, expanding the dicing tape 10 of the dicing die bond film 20 (step S206: room-temperature expansion process in Figure 6). By ensuring sufficient distance (kerf width) between the semiconductor chips 30a with the die bond film (adhesive layer) 3a through the room-temperature expansion process, the semiconductor chips 30a can be more easily recognized by a CCD camera or the like, and re-adhesion of the semiconductor chips 30a with the die bond film (adhesive layer) 3a, which can occur when adjacent semiconductor chips 30a come into contact with each other during pickup, can be prevented. As a result, in the pick-up process described below, the pick-up properties of the semiconductor chip 30a with the die bond film (adhesive layer) 3a are improved.

9(d), for convenience, the edge portion of the die bond film 3a (adhesive layer) of the small piece holding the semiconductor chip 30a is shown as being in close contact with the adhesive layer 2 of the dicing tape 10. However, as shown in the enlarged cross-sectional view of FIG. 10, in reality, the edge portion of the die bond film 3a (adhesive layer) of the small piece holding the semiconductor chip 30a is moderately peeled off from the adhesive layer 2 of the dicing tape 10, and the center portion of the die bond film 3a (adhesive layer) is in close contact with the adhesive layer 2 of the dicing tape 10. During room-temperature expansion, the ambient temperature is higher than during cool expansion, so the adhesion strength between the die bond film 3a (adhesive layer) and the adhesive layer 2 is higher, and expansion can be performed while suppressing the tensile stress generated in the dicing tape 10. Therefore, although the room temperature expansion process may cause the die bond film 3a to peel slightly more than the peeled state after cool expansion shown in Figure 9(c), the peeling does not progress excessively.

The temperature conditions in the room-temperature expansion process are, for example, 10°C or higher, and preferably in the range of 15°C to 30°C. The expansion speed (the speed at which the cylindrical table rises) in the room-temperature expansion process is, for example, in the range of 0.1 mm/sec to 50 mm/sec, and preferably in the range of 0.3 mm/sec to 30 mm/sec. The expansion amount in the room-temperature expansion process is, for example, in the range of 3 mm to 20 mm.

After the table is raised to expand the dicing tape 10 at room temperature, the table vacuum-adsorbs the dicing tape 10. Then, while maintaining the suction, the table lowers, carrying the workpiece, releasing the expanded state of the dicing tape 10. To prevent the kerf width of the semiconductor chip 30a with the die bond film (adhesive layer) 3a on the dicing tape 10 from narrowing after the expanded state is released, it is preferable to heat-shrink the circumferential portion of the dicing tape 10 outside the semiconductor chip 30a holding area by blowing hot air while the dicing tape 10 is vacuum-adsorbed to the table, thereby eliminating any slack in the dicing tape 10 caused by the expansion and maintaining tension. After this heat shrinkage, the table releases the vacuum-adsorbed state. The temperature of the hot air can be adjusted depending on the physical properties of the base film 1, the distance between the hot air outlet and the dicing tape 10, the air volume, and other factors, but a range of 200°C to 250°C is preferred. The distance between the hot air outlet and the dicing tape 10 is preferably, for example, in the range of 15 mm to 25 mm. The air volume is preferably, for example, in the range of 35 L/min to 45 L/min. During the heat shrinking process, the stage of the expanding device is rotated at a rotation speed of, for example, 3°/sec to 10°/sec, while the hot air is blown along the circumferential portion of the dicing tape 10 outside the semiconductor chip 30a holding area.

The dicing tape 10 of the present invention preferably uses, as its base film 1, a resin film composed of a resin composition containing a thermoplastic crosslinked resin (IO) made from an ionomer of an ethylene-unsaturated carboxylic acid copolymer and a polyamide resin (PA). This thermoplastic crosslinked resin (IO) made from an ionomer crosslinked by metal ions provides a sufficiently large recovery force upon heating in response to strain after expansion, i.e., high heat shrinkability. Therefore, during the heat shrink process, when high-temperature hot air is blown onto the slack portion (circumferential portion) of the dicing tape 10 caused by expansion, the circumferential portion of the dicing tape 10 can be easily heat-shrunk to eliminate the slack. Therefore, the kerf width expanded during room-temperature expansion can be maintained by the tension of the dicing tape 10.

Figure 11 is an enlarged plan view of the state in which the edge portion of the small die bond film 3a has been partially peeled off from the adhesive layer 2 of the dicing tape 10 after the above-mentioned cool expansion process to shrink process, as observed with a microscope from the back side (base film side) of the semiconductor chip 30a. The area of the edge portion of the small die bond film 3a peeled from the adhesive layer 2 is not particularly limited as long as the effects of the present invention are not impaired. For example, in state 9 (corresponding to portion 9 in FIG. 10) of one small die bond film 3a piece held on the adhesive layer 2 observed from the back side (base film side) of the semiconductor chip 30a shown in FIG. 11, when the area of the edge portion (shaded portion) of the small die bond film 3a peeled from the adhesive layer 2 is S1 and the area of the portion (white portion) of the small die bond film 3a in close contact with the adhesive layer 2 is S2, the ratio of the area S1 of the edge portion of the small die bond film 3a peeled from the adhesive layer 2 to the total area of the small die bond film 3a (= S1 + S2) is preferably in the range of 10% to 45%. More preferably, it is in the range of 15% to 40%.

If the proportion of the above area S1 is less than 10%, the total force required to peel the semiconductor chip 30a with the die bond film 3a from the adhesive layer 2 may not fully reflect the effect of reducing the adhesive strength A after irradiation with ultraviolet light in the presence of oxygen, i.e., the effect of reducing the force required to peel the edge portion of the semiconductor chip 30a with the die bond film 3a. As a result, when the dicing tape 10 is pushed up from the underside using a push-up jig during pick-up, as described below, it is difficult to trigger peeling from the edge portion, so there is a risk that the effect of improving the pick-up ability of the semiconductor chip 30a with the die bond film 3a compared to conventional methods will be barely noticeable, or that the effect will be minimal.

If the proportion of the area S1 exceeds 45%, that is, if the die bond film 3 is excessively peeled from the pressure-sensitive adhesive layer 2 in the cool expanding step, sufficient external stress cannot be applied to the die bond film 3 via the pressure-sensitive adhesive layer 2, and there is a risk that the die bond film 3 cannot be cleanly cleaved, that the kerf width cannot be sufficiently secured, or that the kerf width varies. Furthermore, there is a risk that the semiconductor chip 30a with the die bond film 3a will be unintentionally displaced or detached in the subsequent manufacturing steps. Furthermore, in the pick-up step described below, when the excessively peeled die bond film re-adheres to the pressure-sensitive adhesive layer 2, the re-adhered area becomes excessively large. Therefore, even if the pressure-sensitive adhesive layer 2 is composed of an active energy ray-curable pressure-sensitive adhesive composition that satisfies the requirements of the present invention, there is a risk that a large amount of energy corresponding to the increase in the re-adhered area will be required to peel the die bond film 3a by pushing it up with a jig from the underside of the dicing tape 10. As a result, the pick-up yield of the semiconductor chip 30a with the die bond film 3a decreases.

In other words, the above-mentioned area S1 is the area where the edge portion of the die bond film 3a peeled off by expanding and the adhesive layer 2 irradiated with UV light in an aerobic environment exposed to air momentarily re-bond upon contact and landing with a suction collet before being pushed up from the underside of the dicing tape 10 using a push-up jig in the next pickup process. Therefore, when the proportion of the above-mentioned area S1 is in the range of 10% to 40%, applying an adhesive layer 2 whose adhesive strength A after UV light irradiation in an aerobic environment is adjusted to 3.50 N/25 mm most effectively reduces the force required to peel the edge portion of the semiconductor chip 30a with the die bond film 3a. On the other hand, in the above-mentioned area S2 portion of the die bond film 3a that is in close contact with the pressure-sensitive adhesive layer 2 and whose proportion of the small piece to the entire area of the die bond film 3a is in the range of 55% to 90%, the adhesive strength B of the pressure-sensitive adhesive layer 2 after irradiation with ultraviolet light in the absence of oxygen is adjusted to 0.25 N/25 mm to 0.70 N/25 mm, so that peeling of the die bond film 3a from the pressure-sensitive adhesive layer 2 toward the center following peeling of the edge portions of the die bond film 3a is facilitated. In the subsequent pick-up process, the total energy required to peel the semiconductor chip 30a with the die bond film 3a from the pressure-sensitive adhesive layer 2 is the sum of the peel force reduction effects in the above-mentioned area S1 and area S2. The dicing tape 10 of this embodiment makes it easier to reduce this total energy compared to conventional methods by balancing the proportions of area S1 and area S2.

The method for determining the ratio of area S1 to area S2 is not particularly limited, and can be determined by conventionally known methods. For example, an image of the edge portion of the cleaved die bond film piece 3a partially peeled from the adhesive layer 2 of the dicing tape 10 observed under a microscope from the back side (base film side) of the semiconductor chip is binarized using image processing software or the like into the portion corresponding to area S1 and the portion corresponding to area S2, and the ratio of each area is determined; or an image is printed on paper or the like, each portion is cut out according to its shape, the mass is measured, and the ratio of each area is determined from the mass ratio.

Subsequently, the dicing tape 10 is irradiated with active energy rays from the base film 1 side, thereby curing and shrinking the pressure-sensitive adhesive layer 2 and reducing the adhesive strength of the pressure-sensitive adhesive layer 2 to the die-bonding film 3a (step S207 in FIG. 6: active energy ray irradiation step). Examples of active energy rays used in the post-irradiation include ultraviolet light, visible light, infrared light, electron beams, beta rays, and gamma rays. Among these active energy rays, ultraviolet light (UV) and electron beams (EB) are preferred, with ultraviolet light (UV) being particularly preferred. The light source for irradiating the ultraviolet light (UV) is not particularly limited, but examples thereof include black light, ultraviolet fluorescent lamps, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, carbon arc lamps, metal halide lamps, and xenon lamps. ArF excimer lasers, KrF excimer lasers, excimer lamps, synchrotron radiation, and the like can also be used. The amount of ultraviolet (UV) radiation is not particularly limited, but is preferably in the range of 100 mJ/cm ² to 2,000 J/cm ² , and more preferably in the range of 150 mJ/cm ² to 1,000 J/cm ² .

Here, as described above, the dicing tape 10 of the present invention is a dicing tape having an integrated light dose of 150 mJ/cm under oxygen and oxygen-free conditions for the pressure-sensitive adhesive layer 2 containing an active energy ray-curable pressure-sensitive adhesive composition including an acrylic adhesive polymer having an active energy ray-reactive carbon-carbon double bond. When ultraviolet rays are irradiated so as to obtain ² , the adhesive strength A (peel angle: 90°, peel rate: 300 mm/min) after ultraviolet irradiation in the presence of oxygen to a stainless steel plate (SUS304 BA plate) at 23 ° C. is in the range of 3.50 N/25 mm or less, and the adhesive strength B (peel angle: 90°, peel rate: 300 mm/min) after ultraviolet irradiation in the absence of oxygen to a stainless steel plate (SUS304 BA plate) at 23 ° C. is in the range of 0.25 N/25 mm or more and 0.70 N/25 mm or less, so that the hardening state due to the crosslinking reaction of the adhesive layer 2 is adjusted, and the force required to peel the semiconductor chip 30 a with the die bond film 3 a from the adhesive layer 2 can be made smaller than conventional. As a result, in the pick-up step described later, the pick-up property of the semiconductor chip 30 a with the die bond film 3 a is improved. In this case, the concentration of active energy ray-reactive carbon-carbon double bonds is preferably adjusted to a value within the range of 0.85 meq to 1.50 meq per 1 g of the active energy ray-curable pressure-sensitive adhesive composition.

Next, each individual semiconductor chip 30a with die bond film (adhesive layer) 3a is peeled off from the adhesive layer 2 of the dicing tape 10 after ultraviolet (UV) irradiation, a so-called pick-up process (step S208 in Figure 6: Peeling (pick-up) process).

As an example of the pickup method, as shown in FIG. 9(e), a semiconductor chip 30a with a die bond film (adhesive layer) 3a, which has been brought into contact with and landed on the surface of the semiconductor chip 30a, is pushed up against the second surface of the base film 1 of the dicing tape 10 by a push-up pin (needle) 60, thereby promoting peeling from the edge of the semiconductor chip 30a with the die bond film 3a. As shown in FIG. 9(f), the pushed-up semiconductor chip 30a with the die bond film (adhesive layer) 3a is then sucked up and lifted by the suction collet 50 of a pickup device (not shown), thereby peeling it off from the adhesive layer 2 of the dicing tape 10. This results in a semiconductor chip 30a with a die bond film (adhesive layer) 3a.

Pickup conditions are not particularly limited as long as they are within a practically acceptable range. Typically, the thrust speed of the thrust pin (needle) 60 is set within the range of 1 mm/sec to 100 mm/sec. However, when the thickness of the semiconductor chip 30a (thickness of the semiconductor wafer) is as thin as 100 μm, it is preferable to set it within the range of 1 mm/sec to 20 mm/sec to prevent damage to the thin-film semiconductor chip 30a. From the perspective of productivity, it is even more preferable to set it within the range of 5 mm/sec to 20 mm/sec.

Furthermore, the push-up height of the push-up pins that allows for picking up without damaging the semiconductor chip 30a is preferably set within a range of 100 μm or more and 600 μm or less from the same viewpoint as above, and more preferably within a range of 100 μm or more and 450 μm or less from the viewpoint of reducing stress on the semiconductor thin-film chip. From the viewpoint of productivity, it is particularly preferable that the push-up height be set within a range of 100 μm or more and 350 μm or less. Dicing tapes that can achieve such a smaller push-up height can be said to have excellent pick-up properties.

As explained above, when the dicing tape 10 of the present invention, which is composed of a base film 1 and an adhesive layer 2, is used in the semiconductor manufacturing process in the form of a dicing die bond film 20 in which a die bond film (adhesive layer) 3 is releasably adhered and laminated onto the adhesive layer 2 of the dicing tape 10, even when a die bond film with high fluidity and thickness, such as a wire-embedded die bond film, is applied, the die bond film 3 is successfully cleaved by cool expansion, and the die bond film 3a after cleavage retains its original shape. This results in a state in which the edge portions of the die bond film 3a of each cleaved semiconductor chip 30a with die bond film 3a are appropriately peeled from the adhesive layer 2 of the dicing tape 10, and the phenomenon in which the peeled edge portions of the die bond film 3a re-adhere to the adhesive layer 2 after ultraviolet irradiation to such an extent that they cannot be easily peeled even when pushed up with a jig from the underside of the dicing tape or when sucked and lifted with a suction collet is greatly suppressed, and the semiconductor chip 30a with the die bond film 3a can be smoothly picked up from the adhesive layer 2 of the dicing tape 10 after ultraviolet irradiation.

Note that the manufacturing method described in Figures 9(a) to (f) is one example (SDBG) of a method for manufacturing a semiconductor chip 30a using a dicing die bond film 20, and the method for using the dicing tape 10 in the form of a dicing die bond film 20 is not limited to the above method. In other words, as long as the dicing die bond film 20 can be attached to the semiconductor wafer 30 during dicing, it can be used in any way without being limited to the above method.

In particular, the dicing tape 10 of the present invention is suitable as a dicing tape for use as a dicing die bond film 20 integrated with a wire-embedded die bond film in manufacturing methods for obtaining thin-film semiconductor chips, such as DBG, stealth dicing, and SDBG. Of course, it can also be integrated with a general-purpose die bond film.

<Method of manufacturing semiconductor device>
A semiconductor device mounted with a semiconductor chip manufactured using a dicing die bond film 20 in which the dicing tape 10 to which the present embodiment is applied and the die bond film 3 are integrated will be specifically described below.

A semiconductor device (semiconductor package) can be obtained, for example, by bonding the semiconductor chip 30a with the die bond film (adhesive layer) 3a described above to a semiconductor chip mounting support member or semiconductor chip by heat and pressure, followed by processes such as wire bonding and sealing with a sealing material.

Figure 12 is a schematic cross-sectional view of one embodiment of a semiconductor device having a stacked structure mounted with a semiconductor chip manufactured using a dicing die bond film 20 that integrates a dicing tape 10 to which this embodiment is applied and a wire-embedded die bond film 3. The semiconductor device 70 shown in Figure 12 includes a semiconductor chip mounting support substrate 71, cured die bond films (adhesive layers) 3a1 and 3a2, a first-layer semiconductor chip 30a1, a second-layer semiconductor chip 30a2, and an encapsulant 75. The semiconductor chip mounting support substrate 71, the cured die bond film 3a1, and the semiconductor chip 30a1 constitute a support member 76 for the semiconductor chip 30a2.

A plurality of external connection terminals 72 are arranged on one surface of the semiconductor chip mounting support substrate 71, and a plurality of terminals 73 are arranged on the other surface of the semiconductor chip mounting support substrate 71. The semiconductor chip mounting support substrate 71 has wires 74 for electrically connecting the connection terminals (not shown) of the semiconductor chips 30a1 and 30a2 to the external connection terminals 72. The semiconductor chip 30a1 is bonded to the semiconductor chip mounting support substrate 71 by a hardened die bond film 3a1 in a manner that fills the irregularities caused by the external connection terminals 72. The semiconductor chip 30a2 is bonded to the semiconductor chip 30a1 by a hardened die bond film 3a2. The semiconductor chips 30a1 and 30a2 and the wires 74 are encapsulated with an encapsulant 75. In this way, the wire-embedded die bond film 3a is suitable for use in semiconductor devices with a stacked configuration in which multiple semiconductor chips 30a are stacked.

Figure 13 is a schematic cross-sectional view of another embodiment of a semiconductor device mounted with a semiconductor chip manufactured using a dicing die bond film 20 formed by integrating a dicing tape 10 to which this embodiment is applied and a general-purpose die bond film 3. The semiconductor device 80 shown in Figure 13 includes a semiconductor chip mounting support substrate 81, a cured die bond film 3a, a semiconductor chip 30a, and an encapsulant 85. The semiconductor chip mounting support substrate 81 is a support member for the semiconductor chip 30a and has wires 84 for electrically connecting connection terminals (not shown) of the semiconductor chip 30a to external connection terminals (not shown) arranged on the main surface of the semiconductor chip mounting support substrate 81. The semiconductor chip 30a is adhered to the semiconductor chip mounting support substrate 81 by the cured die bond film 3a. The semiconductor chip 30a and wires 7 are encapsulated by the encapsulant 85.

The present invention will be further explained in detail using the following examples, but the present invention is not limited to these examples.

1. Preparation of Base Film 1 The following resins were prepared as materials for preparing base films 1(a) to 1(k).

(Thermoplastic crosslinked resin (A) composed of an ionomer of an ethylene-unsaturated carboxylic acid copolymer)
Resin (IO1)
Terpolymer consisting of ethylene/methacrylic acid/2-methyl-propyl acrylate = 80/10/10 mass ratio, degree of neutralization with Zn ²⁺ ions: 60 mol%, melting point: 86°C, MFR: 1 g/10 min (190°C/2.16 kg load), density: 0.96 g/cm ³
Resin (IO2)
Terpolymer consisting of ethylene/methacrylic acid/2-methyl-propyl acrylate = 80/10/10 mass ratio, degree of neutralization with Zn ²⁺ ions: 70 mol%, melting point: 87°C, MFR: 1 g/10 min (190°C/2.16 kg load), density: 0.96 g/cm ³

(Polyamide resin (B))
Resin (PA1)
Nylon 6, melting point: 225°C, density: 1.13 g/ ^cm3

(Other resins (C))
・Resin (TPO)
Thermoplastic polyolefin elastomer (ethylene-α-olefin random copolymer)
・Resin (POPE)
Polyolefin-polyether block copolymer (polymeric antistatic agent), melting point: 115°C, MFR: 15g/10min (190°C/2.16kg load)
・Resin (PP)
Random copolymer polypropylene, melting point 138°C
・Resin (EVA)
Ethylene-vinyl acetate copolymer, vinyl acetate content 20% by mass, melting point 82°C, density: 0.94 g/cm ³

(Base film 1(a))
An ionomer thermoplastic crosslinked resin (A) (IO1) and a polyamide resin (B) (PA1) were prepared. First, the ionomer thermoplastic crosslinked resin (A) = (IO1) and the polyamide resin (B) = (PA1) were dry-blended at a mass ratio of (A):(B) = 95:5. The dry-blended mixture was then introduced into the resin inlet of a twin-screw extruder and melt-kneaded at a die temperature of 230°C to obtain a resin composition for the substrate film 1(a). The resulting resin composition was introduced into each extruder using a single-type (same resin) three-layer T-die film molding machine and molded at a processing temperature of 240°C to produce a three-layer substrate film 1(a) with a thickness of 90 μm made from the same resin composition. The thicknesses of the layers were: first layer (the side contacting the pressure-sensitive adhesive layer 2), second layer, and third layer = 20 μm, 50 μm, and 20 μm. The mass ratio of the total amount of the thermoplastic crosslinked resin (A) composed of an ionomer to the total amount of the polyamide resin (B) in the entire layer was (A):(B)=95:5.

(Base film 1(b))
A 90 μm-thick three-layer substrate film 1(b) was produced using the same resin composition in the same manner as substrate film 1(a), except that the ionomer thermoplastic crosslinked resin (A) = (IO1) and the polyamide resin (B) = (PA1) were dry-blended in a mass ratio of (A):(B) = 90:10. The thicknesses of the layers were 20 μm/50 μm/20 μm for the first layer (the side in contact with the pressure-sensitive adhesive layer 2), second layer, and third layer. The mass ratio of the total amount of the ionomer thermoplastic crosslinked resin (A) to the total amount of the polyamide resin (B) in the entire layer was 90:10.

(Base film 1 (c))
A 90 μm thick three-layer substrate film 1(c) was produced using the same resin composition in the same manner as substrate film 1(a), except that the ionomer thermoplastic crosslinked resin (A) = (IO1) and the polyamide resin (B) = (PA1) were dry-blended in a mass ratio of (A):(B) = 85:15. The thicknesses of the layers were 20 μm/50 μm/20 μm for the first layer (the side in contact with the pressure-sensitive adhesive layer 2), second layer, and third layer. The mass ratio of the total amount of the ionomer thermoplastic crosslinked resin (A) to the total amount of the polyamide resin (B) in the entire layer was 85:15.

(Base film 1 (d))
A three-layer substrate film 1(d) having a thickness of 90 μm was prepared from the same resin composition in the same manner as substrate film 1(a), except that the thermoplastic crosslinked resin (A) (IO1) composed of the ionomer and the polyamide resin (B) (PA1) were dry-blended in a mass ratio of (A):(B) = 80:20. The thicknesses of the layers were 1st layer (the side contacting the pressure-sensitive adhesive layer 2), 2nd layer, and 3rd layer = 20 μm, 50 μm, and 20 μm. The mass ratio of the total amount of thermoplastic crosslinked resin (A) composed of the ionomer to the total amount of polyamide resin (B) in the entire layer was (A):(B) = 80:20.

(Base film 1(e))
A 90 μm-thick three-layer substrate film 1(e) was produced using the same resin composition in the same manner as substrate film 1(a), except that the ionomer thermoplastic crosslinked resin (A) = (IO1) and the polyamide resin (B) = (PA1) were dry-blended in a mass ratio of (A):(B) = 72:28. The thicknesses of the layers were 20 μm/50 μm/20 μm for the first layer (the side in contact with the pressure-sensitive adhesive layer 2), second layer, and third layer. The mass ratio of the total amount of the ionomer thermoplastic crosslinked resin (A) to the total amount of the polyamide resin (B) in the entire layer was 72:28.

(Base film 1(f))
The thermoplastic crosslinked resin (A) (IO1) composed of the ionomer, the polyamide resin (B) (PA1), and the other resins (C) composed of a thermoplastic polyolefin elastomer (ethylene-α-olefin random copolymer) (TPO) and a polyolefin-polyether block copolymer (POPE) were prepared. First, the thermoplastic crosslinked resin (A) composed of the ionomer (IO1) and the polyamide resin (B) (PA1) were dry-blended in a mass ratio of (A):(B) = 90:10 to form the resins for the first and second layers. The dry-blended mixture was then introduced into the resin inlet of a twin-screw extruder and melt-kneaded at a die temperature of 230°C to obtain resin compositions for the first and second layers of the base film 1 (g). The resin for the third layer was a dry blend of a thermoplastic crosslinked ionomer resin (A) = (IO1), a polyamide resin (B) = (PA1), a thermoplastic polyolefin elastomer (TPO), and a polyolefin-polyether block copolymer (POPE) in a mass ratio of 76:8:8:8. The dry-blended mixture was then introduced into the resin inlet of a twin-screw extruder and melt-kneaded at a die temperature of 230°C to obtain a resin composition for the third layer of the substrate film 1(f). Each resin composition and resin was introduced into each extruder using a two-type (two types of resin) three-layer T-die film molding machine and molded at a processing temperature of 240°C to produce a three-layer substrate film 1(f) with a thickness of 80 μm, made from two types of resin compositions. The thicknesses of the layers were: first layer (the side contacting the pressure-sensitive adhesive layer 2), second layer, and third layer = 30 μm, 30 μm, and 20 μm. The mass ratio of the total amount of thermoplastic crosslinked resin (A) composed of ionomer to the total amount of polyamide resin (B) in the entire layer is (A):(B)=90:10. The total content of resin (A) and resin (B) in the entire layer is 95 mass%.

(Base film 1 (g))
The thermoplastic crosslinked resin (A) (IO1) composed of the ionomer, the polyamide resin (B) (PA1), and the thermoplastic polyolefin elastomer (ethylene-α-olefin random copolymer) (TPO) were prepared as the other resin (C). First, the thermoplastic crosslinked resin (A) composed of the ionomer (IO1) and the polyamide resin (B) (PA1) were dry-blended at a mass ratio of (A):(B) = 85:15 to prepare the resins for the first and third layers. The dry-blended mixture was then introduced into the resin inlet of a twin-screw extruder and melt-kneaded at a die temperature of 230°C to obtain resin compositions for the first and third layers of the base film 1 (g). The thermoplastic polyolefin elastomer (ethylene-α-olefin random copolymer) (TPO) was used alone as the resin for the second layer. Each resin composition and resin was fed into a two-type (two types of resin) three-layer T-die film molding machine, and molded at a processing temperature of 240°C to produce a three-layer substrate film 1 (g) with a thickness of 90 μm. The thickness of each layer was 30 μm/30 μm/30 μm for the first layer (the side contacting the pressure-sensitive adhesive layer 2), the second layer, and the third layer. The mass ratio of the total amount of thermoplastic crosslinked resin (A) composed of an ionomer to the total amount of polyamide resin (B) in the entire layer was 85:15 (total amount of (A):total amount of (B)). The total content of resin (A) and resin (B) in the entire layer was 67% by mass.

(Base film 1 (h))
The thermoplastic crosslinked resins (A) composed of the ionomer (IO1) and (IO2) were prepared, and the polyamide resin (B) was prepared as (PA1). First, the thermoplastic crosslinked resin (A) composed of the ionomer (IO1) and the polyamide resin (B) composed of (PA1) were dry-blended at a mass ratio of (A):(B) = 90:10 to form the resins for the first and third layers. The dry-blended mixture was then introduced into the resin inlet of a twin-screw extruder and melt-kneaded at a die temperature of 230°C to obtain resin compositions for the first and third layers of the base film 1 (h). Furthermore, the thermoplastic crosslinked resin (A) composed of the ionomer (IO2) was used alone as the resin for the second layer. Each resin composition and resin was fed into the respective extruders of a two-type (two types of resin) three-layer T-die film molding machine and molded at a processing temperature of 240°C to produce a three-layer substrate film 1 (g) made of two types of resin compositions and having a thickness of 90 μm. The thicknesses of the layers were: first layer (the side contacting the pressure-sensitive adhesive layer 2)/second layer/third layer = 30 μm/30 μm/30 μm. The mass ratio of the total amount of thermoplastic crosslinked resin (A) composed of ionomer to the total amount of polyamide resin (B) in the entire layer was 93:7 (total amount of (A):total amount of (B)).

(Base film 1(i))
An ionomer resin (A) (IO1) was prepared. A three-layer substrate film 1(i) with a thickness of 90 μm was prepared using the same resin composition (ionomer resin (A) only) in the same manner as substrate film 1(a), except that polyamide resin (B) = (PA1) was not dry-blended. The thicknesses of the layers were: first layer (the side in contact with pressure-sensitive adhesive layer 2), second layer, and third layer = 20 μm, 50 μm, and 20 μm.

(Base film 1(j))
A 90 μm-thick substrate film 1(j) having a three-layer structure using two resin compositions was produced in the same manner as substrate film 1(g), except that the thicknesses of the layers of substrate film 1 were set to 20 μm/50 μm/20 μm for the first layer (the side in contact with pressure-sensitive adhesive layer 2), second layer, and third layer. The mass ratio of the total amount of thermoplastic crosslinked resin (A) composed of ionomer to the total amount of polyamide resin (B) in the entire layer was 90:10 (total amount of (A):total amount of (B)). The total content of resin (A) and resin (B) in the entire layer was 44 mass%.

(Base film 1(k))
Other resins (C) were prepared as (PP) and (EVA). (PP) was used as the resin for the first and third layers, and (EVA) was used as the resin for the second layer. Each resin was fed into a two-type (two types of resin) three-layer T-die film molding machine, and molded at a processing temperature of 150 ° C. to produce a three-layer substrate film 1 (k) with a thickness of 80 μm. The thickness of each layer was 1st layer (the side contacting the pressure-sensitive adhesive layer) / 2nd layer / 3rd layer = 8 μm / 64 μm / 8 μm.

[Elastic modulus of base film at 5% elongation]
The elastic modulus Y in _the MD direction at 5% elongation and the elastic modulus Y in the TD _direction at 5% elongation at 0°C of the base film 1 were measured by the following method. First, test pieces having a length of 100 mm (MD direction) and a width of 10 mm (TD direction) were prepared as samples for measurement in the MD direction (number of samples N = 5), and test pieces having a length of 100 mm (TD direction) and a width of 10 mm (MD direction) were prepared as samples for measurement in the TD direction (number of samples N = 5). Next, using a tension-compression testing machine (model: MinebeaTechnoGraph TG-5kN) manufactured by MinebeaMitsumi Inc., both ends of the longitudinal direction of the test piece were fixed with chucks so that the initial distance between the chucks was 20 mm, and the test piece was placed in a thermostatic chamber (model: THB-A13-038) manufactured by MinebeaMitsumi Inc. at 0°C for 1 minute, after which a tensile test was performed at a rate of 100 mm/min, and a tensile load-elongation curve was measured. Then, from the obtained tensile load-elongation curve, the slope of the line connecting the origin (the start point of elongation) and the point on the curve corresponding to the tensile load value (unit: N) when elongated 1.0 mm from the origin (5% elongation relative to the initial distance between the chucks of 20 mm) was calculated, and the elastic modulus Y (unit: MPa) at 5% elongation was calculated using the above-mentioned formula. Measurements were performed on five samples in each direction, and the average values were designated as the elastic modulus at 5% elongation in the MD direction _YMD and the elastic modulus at 5% elongation in the TD direction _YTD . Using these values, the average elastic modulus at 5% elongation at 0°C of the substrate film 1 formed above ( _YMD + _YTD )/2 was calculated.

The average values of the elastic modulus at 5% elongation (Y _MD +Y _TD )/2 at 0°C of the base films 1(a) to 1(k) used as the base film 1 of the dicing tape 10 of the Examples and Comparative Examples are as shown in Tables 1 to 9, respectively.

2. Preparation of a solution of the adhesive composition
As adhesive compositions for the adhesive layer 2 of the dicing tape 10, solutions of the following active energy ray-curable acrylic adhesive compositions 2(a) to 2(u) were prepared.
The copolymerizable monomer components constituting the base polymer (acrylic ester copolymer) of these pressure-sensitive adhesive compositions include:
2-ethylhexyl acrylate (2-EHA, molecular weight: 184.3, Tg: -70°C),
2-hydroxyethyl acrylate (2-HEA, molecular weight: 116.12, Tg: -15°C),
Methacrylic acid (MAA, molecular weight: 86.06: Tg: 228 ° C.),
was prepared.

Further, as the polyisocyanate-based crosslinking agent, a TDI-based polyisocyanate-based crosslinking agent manufactured by Tosoh Corporation (trade name: Coronate L-45E, solid content: 45% by mass, isocyanate group content in solution: 8.05% by mass, isocyanate group content in solid content: 17.89% by mass, calculated number of isocyanate groups: average 2.8/molecule, theoretical molecular weight: 656.64) was used.
- HDI-based polyisocyanate crosslinking agent (trade name: Coronate HL, solid content: 75% by mass, isocyanate group content in solution: 12.8% by mass, isocyanate group content in solid content: 17.07% by mass, calculated number of isocyanate groups: average 2.6/molecule, theoretical molecular weight: 638.75),
was prepared.

(Solution of active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a))
2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), and methyl methacrylate (MMA) were prepared as copolymerizable monomer components. These copolymerizable monomer components were mixed to a copolymerization ratio of 2-EHA/2-HEA/MMA = 81.5 parts by mass/17.5 parts by mass/1.0 part by mass (= 442.21 mmol/150.71 mmol/11.62 mmol), and a solution of a hydroxyl-containing base polymer (acrylic ester copolymer) was synthesized by solution radical polymerization using ethyl acetate as the solvent and azobisisobutyronitrile (AIBN) as the initiator. The Tg of the resulting base polymer, calculated using the Fox equation, was -61°C.

Next, 19.2 parts by mass (123.75 mmol: 82.11 mol% relative to 2-HEA) of 2-isocyanatoethyl methacrylate (trade name: Karenz MOI, molecular weight: 155.15, isocyanate group: 1 per molecule, double bond group: 1 per molecule) having an isocyanate group and an active energy ray-reactive carbon-carbon double bond manufactured by Showa Denko K.K. was blended with 100 parts by mass of the solid content of this base polymer and reacted with some of the hydroxyl groups of 2-HEA to synthesize a solution of acrylic adhesive polymer (A) having a carbon-carbon double bond in the side chain (solid content concentration: 50% by mass, weight average molecular weight Mw: 330,000, solid content hydroxyl value: 12.7 mg KOH/g, solid content acid value: 5.5 mg KOH/g, carbon-carbon double bond content: 1.04 meq/g). In the above reaction, 0.05 parts by mass of hydroquinone monomethyl ether was used as a polymerization inhibitor to maintain the reactivity of the carbon-carbon double bond.

Next, 200 parts by mass (100 parts by mass in terms of solid content) of the solution of acrylic adhesive polymer (A) synthesized above was mixed with 4.0 parts by mass of an α-hydroxyalkylphenone photopolymerization initiator (trade name: Omnirad 184) manufactured by IGM Resins B.V., 0.8 parts by mass of a benzyl methyl ketal photopolymerization initiator (trade name: Omnirad 651) manufactured by IGM Resins B.V., 1.0 part by mass of an α-aminoalkylphenone photopolymerization initiator (trade name: Omnirad 379EG) manufactured by IGM Resins B.V., and 1.0 part by mass of a hydroxyalkylphenone photopolymerization initiator (trade name: Omnirad 379EG) manufactured by IGM Resins B.V. A solution of active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) with a solids concentration of 22% by mass was prepared by blending 0.4 parts by mass of an acylphosphine oxide photopolymerization initiator (trade name: Omnirad 819) manufactured by Tosoh Corporation as a crosslinking agent and 5.5 parts by mass (4.1 parts by mass, 7.65 mmol equivalent to solids) of an HDI polyisocyanate crosslinking agent (trade name: Coronate HL, solids concentration: 75% by mass) manufactured by Tosoh Corporation as a crosslinking agent. The mixture was diluted with ethyl acetate and stirred to prepare an active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a). As shown in Table 1, the equivalent ratio (NCO/OH) of the isocyanate groups (NCO) of the polyisocyanate crosslinking agent to the hydroxyl groups (OH) of the acrylic pressure-sensitive adhesive polymer in active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) was 0.74, the residual hydroxyl group concentration was 0.06 mmol/g, and the carbon-carbon double bond concentration was 1.00 meq/g.

(Solutions of active energy ray-curable acrylic pressure-sensitive adhesive compositions 2(b) to 2(u))
Solutions of acrylic adhesive polymers (B) to (G) were synthesized by appropriately changing the copolymerization ratio of the copolymerizable monomer component, the amount of the active energy ray-reactive compound, and the copolymerizable monomer component for the acrylic adhesive polymer (A) as shown in Tables 4, 5, and 9, respectively. The Tg, weight average molecular weight Mw, acid value, and hydroxyl value of the base polymer in the synthesized acrylic adhesive polymers (B) to (G) are shown in Tables 4, 5, and 9, respectively. Subsequently, using these acrylic adhesive polymer solutions, a photopolymerization initiator and a polyisocyanate-based crosslinking agent were appropriately blended with 100 parts by mass of the acrylic adhesive polymers (A) to (G) in terms of solid content as shown in Tables 3 to 6, 8, and 9, respectively, to prepare solutions of active energy ray-curable acrylic adhesive compositions 2(b) to 2(u). In the active energy ray-curable acrylic pressure-sensitive adhesive compositions 2(b) to 2(u), the equivalent ratio (NCO/OH) of the isocyanate group (NCO) in the polyisocyanate crosslinking agent to the hydroxyl group (OH) in the acrylic pressure-sensitive adhesive polymer, the residual hydroxyl group concentration, and the carbon-carbon double bond concentration are as shown in Tables 3 to 6, 8, and 9, respectively.

3. Preparation of Solutions of Adhesive Compositions As adhesive compositions for the die bond film (adhesive layer) 3 of the dicing die bond film 20, solutions of the following adhesive compositions 3(a) to 3(d) were prepared.

(Solution of Adhesive Composition 3(a))
For a wire-embedded die bond film, the following adhesive composition solution 3 (a) was prepared. First, 26 parts by mass of a bisphenol type epoxy resin (trade name: R2710, epoxy equivalent: 170, molecular weight: 340, liquid at room temperature) manufactured by Printec Co., Ltd. as a thermosetting resin, 36 parts by mass of a cresol novolac type epoxy resin (trade name: YDCN-700-10, epoxy equivalent: 210, softening point: 80 ° C.) manufactured by Tohto Kasei Co., Ltd., 1 part by mass of a phenolic resin (trade name: Milex XLC-LL, hydroxyl equivalent: 175, softening point: 77 ° C., water absorption: 1% by mass, heat mass loss rate: 4% by mass) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, and 25 parts by mass of a phenolic resin (trade name: HE200C-10, hydroxyl equivalent: 200, softening point: 71 ° C., water absorption: 1% by mass, heat mass loss rate: 4% by mass) manufactured by Air Water Inc. 12 parts by mass of phenolic resin manufactured by Air Water Inc. (trade name: HE910-10, hydroxyl equivalent: 101, softening point: 83°C, water absorption: 1 mass%, heat mass loss rate: 3 mass%), 15 parts by mass of silica filler dispersion manufactured by Admatechs Co., Ltd. (trade name: SC2050-HLG, average particle size: 0.50 μm) as an inorganic filler, 14 parts by mass of silica filler dispersion manufactured by Admatechs Co., Ltd. (trade name: SC1030-HJA, average particle size: 0.25 μm), and 1 part by mass of silica manufactured by Nippon Aerosil Co., Ltd. (trade name: Aerosil R972, average particle size: 0.016 μm). Cyclohexanone was added as a solvent to a resin composition, and the mixture was stirred and mixed, and further dispersed for 90 minutes using a bead mill.

Next, 37 parts by weight of a glycidyl group-containing (meth)acrylic acid ester copolymer with a low weight average molecular weight Mw as the thermoplastic resin, 9 parts by weight of a glycidyl group-containing (meth)acrylic acid ester copolymer with a high weight average molecular weight Mw, 0.7 parts by weight of gamma-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation and 0.3 parts by weight of gamma-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation as the silane coupling agent, and 0.03 parts by weight of 1-cyanoethyl-2-phenylimidazole (trade name: Curesol 2PZ-CN) manufactured by Shikoku Kasei Corporation as the curing accelerator were added to the above resin composition, stirred and mixed, filtered through a 100-mesh filter, and then vacuum degassed to prepare a solution of adhesive composition 3(a) with a solids concentration of 20% by weight. The content ratio of each resin component in the total resin component (total mass of thermoplastic resin, thermosetting resin, and crosslinking agent) was glycidyl group-containing (meth)acrylic acid ester copolymer: epoxy resin: phenolic resin = 31.5% by mass: 42.5% by mass: 26.0% by mass. The content of inorganic filler relative to the total resin component was 20.5% by mass.

(Solution of Adhesive Composition 3(b))
For a wire-embedded die-bonding film, the following adhesive composition solution 3(b) was prepared and prepared. First, 21 parts by mass of bisphenol F epoxy resin (trade name: YDF-8170C, epoxy equivalent: 159, molecular weight: 310, liquid at room temperature) manufactured by Tohto Kasei Co., Ltd. as a thermosetting resin, 33 parts by mass of cresol novolac epoxy resin (trade name: YDCN-700-10, epoxy equivalent: 210, softening point: 80°C) manufactured by Tohto Kasei Co., Ltd. as a crosslinking agent, 46 parts by mass of phenolic resin (trade name: HE200C-10, hydroxyl equivalent: 200, softening point: 71°C, water absorption: 1% by mass, heat mass loss rate: 4% by mass) manufactured by Air Water Inc. as a crosslinking agent, and 18 parts by mass of silica filler dispersion (trade name: SC1030-HJA, average particle size: 0.25 μm) manufactured by Admatechs Co., Ltd. as an inorganic filler were added to a resin composition, and the mixture was stirred and mixed, and further dispersed for 90 minutes using a bead mill.

Next, to the above resin composition was added 16 parts by mass of a glycidyl group-containing (meth)acrylic acid ester copolymer with a low weight average molecular weight Mw as the thermoplastic resin, 64 parts by mass of a glycidyl group-containing (meth)acrylic acid ester copolymer with a high weight average molecular weight Mw, 1.3 parts by mass of gamma-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation and 0.6 parts by mass of gamma-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation as the silane coupling agent, and 0.05 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curesol 2PZ-CN) manufactured by Shikoku Kasei Corporation as the curing accelerator, followed by stirring and mixing. The mixture was filtered through a 100-mesh filter and then vacuum degassed to prepare a solution of adhesive composition 3(b) with a solids concentration of 20% by mass. The proportions of each resin component in the total resin component (total mass of thermoplastic resin, thermosetting resin, and crosslinking agent) were glycidyl group-containing (meth)acrylic acid ester copolymer, epoxy resin, and phenolic resin = 44.4% by mass, 30.0% by mass, and 25.6% by mass. The inorganic filler content was 10.0% by mass relative to the total resin component.

(Solution of Adhesive Composition 3(c))
For a wire-embedded die bond film, the following adhesive composition solution 3(c) was prepared. First, 11 parts by mass of a bisphenol type epoxy resin (trade name: R2710, epoxy equivalent: 170, molecular weight: 340, liquid at room temperature) manufactured by Printec Co., Ltd. as a thermosetting resin, 40 parts by mass of a dicyclopentadiene type epoxy resin (trade name: HP-7200H, epoxy equivalent: 280, softening point: 83°C) manufactured by DIC Corporation, 18 parts by mass of a bisphenol S type epoxy resin (trade name: EXA-1514, epoxy equivalent: 300, softening point: 75°C) manufactured by DIC Corporation, 1 part by mass of a phenolic resin (trade name: Milex XLC-LL, hydroxyl equivalent: 175, softening point: 77°C, water absorption: 1% by mass, heat mass loss rate: 4% by mass) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, and 1 part by mass of a phenolic resin (trade name: Product name: HE200C-10, hydroxyl equivalent: 200, softening point: 71 ° C, water absorption: 1 mass%, heat mass loss rate: 4 mass%) 20 parts by mass, phenolic resin manufactured by Air Water Inc. (trade name: HE910-10, hydroxyl equivalent: 101, softening point: 83 ° C, water absorption: 1 mass%, heat mass loss rate: 3 mass%) 10 parts by mass, silica filler dispersion manufactured by Admatechs Co., Ltd. (trade name: SC1030-HJA, average particle size: 0.25 μm) 24 parts by mass, silica manufactured by Nippon Aerosil Co., Ltd. (trade name: Aerosil R972, average particle size: 0.016 μm) 0.8 parts by mass, cyclohexanone as a solvent was added to the resin composition, stirred and mixed, and further dispersed for 90 minutes using a bead mill.

Next, 30 parts by mass of a glycidyl group-containing (meth)acrylic acid ester copolymer with a low weight average molecular weight Mw as the thermoplastic resin, 7.5 parts by mass of a glycidyl group-containing (meth)acrylic acid ester copolymer with a high weight average molecular weight Mw, 0.57 parts by mass of gamma-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation and 0.29 parts by mass of gamma-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation as the silane coupling agent, and 0.023 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curesol 2PZ-CN) manufactured by Shikoku Kasei Corporation as the curing accelerator were added to the above resin composition, stirred and mixed, filtered through a 100-mesh filter, and then vacuum degassed to prepare a solution of adhesive composition 3(c) with a solids concentration of 20% by mass. The proportions of each resin component in the total resin component (total mass of thermoplastic resin, thermosetting resin, and crosslinking agent) were glycidyl group-containing (meth)acrylic acid ester copolymer, epoxy resin, and phenolic resin = 27.3 mass%, 50.2 mass%, and 22.5 mass%. The inorganic filler content was 18.0 mass% of the total resin component.

(Solution of Adhesive Composition 3(d))
For general-purpose die-bonding films, a solution of the following adhesive composition 3 (d) was prepared. First, 54 parts by mass of cresol novolac epoxy resin (trade name: YDCN-700-10, epoxy equivalent 210, softening point 80 ° C.) manufactured by Tohto Kasei Co., Ltd. as a thermosetting resin, 46 parts by mass of phenolic resin (trade name: Milex XLC-LL, hydroxyl equivalent: 175, water absorption: 1.8%) manufactured by Mitsui Chemicals, Inc. as a crosslinking agent, and 32 parts by mass of silica (trade name: Aerosil R972, average particle size 0.016 μm) manufactured by Nippon Aerosil Co., Ltd. as an inorganic filler. Cyclohexanone was added as a solvent to the resin composition, and the mixture was stirred and mixed, and further dispersed for 90 minutes using a bead mill.

Next, 274 parts by mass of a glycidyl group-containing (meth)acrylic acid ester copolymer was added to the resin composition as a thermoplastic resin, 5.0 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-1160) manufactured by GE Toshiba Corporation and 1.7 parts by mass of γ-ureidopropyltriethoxysilane (trade name: NUC A-189) manufactured by GE Toshiba Corporation as silane coupling agents, and 0.1 parts by mass of 1-cyanoethyl-2-phenylimidazole (trade name: Curesol 2PZ-CN) manufactured by Shikoku Kasei Corporation as a curing accelerator. The mixture was stirred and mixed, filtered through a 100-mesh filter, and then vacuum degassed to prepare a solution of adhesive composition 3(d) with a solids concentration of 20% by mass. The proportions of each resin component in the total resin component (total mass of thermoplastic resin, thermosetting resin, and crosslinking agent) were glycidyl group-containing (meth)acrylic acid ester copolymer: epoxy resin: phenolic resin = 73.3 mass%: 14.4 mass%: 12.3 mass%. The inorganic filler content was 8.6 mass% of the total resin component.

4. Preparation of dicing tape 10 and dicing die bond film 20 (Example 1)
A solution of the active energy ray-curable acrylic pressure-sensitive adhesive composition (a) was applied to the release-treated surface of a release liner (thickness: 38 μm, polyethylene terephthalate film) so that the thickness of the pressure-sensitive adhesive layer 2 after drying would be 8 μm, and the solution was heated at 100° C. for 3 minutes to dry the solvent. After that, the surface of the first layer side of the base film 1(a) was bonded to the pressure-sensitive adhesive layer 2 to produce a raw sheet of dicing tape 10. Thereafter, the raw sheet of dicing tape 10 was stored at a temperature of 23° C. for 96 hours to crosslink and cure the pressure-sensitive adhesive layer 2.

Next, a solution of adhesive composition 3(a) for forming die bond film (adhesive layer) 3 was prepared, and the solution of adhesive composition 3(a) was applied to the release-treated surface of a release liner (thickness: 38 μm, polyethylene terephthalate film) so that the thickness of die bond film (adhesive layer) 3 after drying would be 50 μm. The solvent was dried by heating in two stages, first at 90°C for 5 minutes and then at 140°C for 5 minutes, to produce die bond film (adhesive layer) 3 equipped with a release liner. If necessary, a protective film (e.g., polyethylene film) may be attached to the dried surface of die bond film (adhesive layer) 3.

Next, the die bond film (adhesive layer) 3 with the release liner prepared above was cut into a circle with a diameter of 335 mm, along with the release liner, and the exposed adhesive layer surface (the surface without the release liner) of the die bond film (adhesive layer) 3 was bonded to the pressure-sensitive adhesive layer 2 surface of the dicing tape 10 from which the release liner had been peeled off. The bonding conditions were 23°C, 10 mm/sec, and a linear pressure of 30 kgf/cm.

Finally, the dicing tape 10 was cut into a circle with a diameter of 370 mm to produce a dicing die bond film 20 (DDF(a)) in which a circular die bond film (adhesive layer) 3 with a diameter of 335 mm was laminated onto the center of the adhesive layer 2 of the circular dicing tape 10 with a diameter of 370 mm.

(Examples 2 to 8)
Dicing die bond films 20 (DDF(b) to DDF(h)) were produced in the same manner as in Example 1, except that the base film 1(a) was changed to the base film 1(b) to 1(h) shown in Tables 1 and 2, respectively.

(Examples 9 to 23)
Dicing die bond films 20 (DDF(i) to DDF(w)) were produced in the same manner as in Example 2, except that the solution of active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) was changed to the solutions of active energy ray-curable acrylic pressure-sensitive adhesive compositions 2(b) to 2(p) shown in Tables 3 to 6, respectively.

(Example 24)
A dicing die bond film 20 (DDF (x)) was produced in the same manner as in Example 2, except that the solution of adhesive composition 3 (a) was changed to a solution of adhesive composition 3 (b) and the thickness of the die bond film (adhesive layer) 3 after drying was changed to 30 μm.

Example 25
A dicing die bond film 20 (DDF(y)) was produced in the same manner as in Example 2, except that the solution of adhesive composition 3(a) was changed to a solution of adhesive composition 3(c).

(Example 26)
A dicing die bond film 20 (DDF(z)) was produced in the same manner as in Example 2, except that the solution of adhesive composition 3(a) was changed to a solution of adhesive composition 3(d) and the thickness of the die bond film (adhesive layer) 3 after drying was changed to 20 μm.

(Comparative Example 1)
A dicing die bond film 20 (DDF(aa)) was produced in the same manner as in Example 1, except that the base film 1(a) was changed to the base film 1(i), the solution of the active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) was changed to the solution of the active energy ray-curable acrylic pressure-sensitive adhesive composition 2(q) shown in Table 8, and the solution of the adhesive composition 3(a) was changed to the solution of the adhesive composition 3(c).

(Comparative Example 2)
Dicing die bond film 20 (DDF(bb)) was produced in the same manner as in Comparative Example 1, except that base film 1(a) was changed to base film 1(j) and the solution of adhesive composition 3(c) was changed to a solution of adhesive composition 3(a).

(Comparative Example 3)
A dicing die bond film 20 (DDF(cc)) was produced in the same manner as in Comparative Example 2, except that the base film 1(a) was changed to the base film 1(k).

(Comparative Example 4)
A dicing die bond film 20 (DDF(dd)) was produced in the same manner as in Comparative Example 1, except that the solution of active energy ray-curable acrylic pressure-sensitive adhesive composition 2(q) was changed to the solution of active energy ray-curable acrylic pressure-sensitive adhesive composition 2(r) shown in Table 8.

(Comparative Examples 5 to 7)
Dicing die bond films 20 (DDF(ee) to DDF(gg)) were produced in the same manner as in Example 2, except that the solution of the active energy ray-curable acrylic pressure-sensitive adhesive composition 2(a) was changed to a solution of the active energy ray-curable acrylic pressure-sensitive adhesive composition 2(s) to 2(u) shown in Table 9, respectively.

5. Measurement of adhesive strength after ultraviolet irradiation of dicing tape and shear viscosity of die bond film The adhesive strength after ultraviolet irradiation of the dicing tape 10 produced in Examples 1 to 26 and Comparative Examples 1 to 7 and the shear viscosity of the die bond film 3 were measured by the method shown below.

5.1 Measurement of adhesive strength of the pressure-sensitive adhesive layer 2 of the dicing tape 10 after irradiation with ultraviolet light in the presence of oxygen and adhesive strength of the pressure-sensitive adhesive layer 2 of the dicing tape 10 to the die bond film (adhesive layer) 3 after irradiation with ultraviolet light in the absence of oxygen The adhesive strength A of the pressure-sensitive adhesive layer 2 after irradiation with ultraviolet light in the presence of oxygen and the adhesive strength B of the pressure-sensitive adhesive layer 2 after irradiation with ultraviolet light in the absence of oxygen were measured for the dicing tapes 10 produced in Examples 1 to 26 and Comparative Examples 1 to 7 above by the following method.

5.1.1 Adhesion strength A after irradiation with ultraviolet light under aerobic conditions
First, the dicing tape 10 was cut to a size of 25 mm wide (in the TD direction of the base film 1) and 120 mm long (in the MD direction of the base film 1). Next, the release liner was peeled off, and the dicing tape 10 was irradiated with ultraviolet (UV) rays having a central wavelength of 367 nm from the pressure-sensitive adhesive layer side 2 side using a metal halide lamp (irradiation intensity: 70 mW/cm ² , accumulated light quantity: 150 mJ/cm ² ). After that, the dicing tape 10 was neatly pressed and bonded to a stainless steel plate (SUS304 BA plate) from the edge of the pressure-sensitive adhesive layer side 2 using a 2 kg rubber roller, with the rubber roller moving back and forth once at a speed of about 5 mm/sec in an environment of a temperature of 23°C and a humidity of 50% RH, to prepare a test specimen for measurement. After 20 minutes of standing, the test piece was measured for adhesive strength (unit: N/25 mm) at a peel angle of 90° from a stainless steel plate (SUS304 BA plate) using a flexible peel angle adhesive/film peeling analyzer shown in Figure 4 in an environment of 23°C temperature and 50% RH. The peel speed was 300 mm/min. Measurements were performed on three test pieces, and the average of the values for the three specimens was taken as the adhesive strength A of the dicing tape 10 after ultraviolet irradiation in an oxygen-containing atmosphere.

5.1.2 Adhesion strength after UV irradiation in the absence of oxygen B
First, the dicing tape 10 was cut to a width (TD direction of the base film 1) of 25 mm and a length (MD direction of the base film 1) of 120 mm. Next, the release liner was peeled off and the adhesive layer 2 of the dicing tape 10 was pressed neatly against a stainless steel plate (SUS304 BA plate) using a rubber roller weighing 2 kg, at a temperature of 23°C and a humidity of 50% RH, by moving the rubber roller back and forth once at a speed of approximately 5 mm/sec. After leaving the tape to stand for 20 minutes, the base film 1 side of the dicing tape 10 was irradiated with ultraviolet (UV) rays with a center wavelength of 367 nm using a metal halide lamp (irradiation intensity: 70 mW/cm ² , cumulative light amount: 150 mJ/cm ² ) to prepare a test piece for measurement. For this test piece, the adhesive strength (unit: N/25 mm) of the dicing tape 10 at a peel angle of 90° to a stainless steel plate (SUS304 BA plate) was measured using a flexible peel angle adhesive/film peeling analyzer shown in Figure 4, in the same manner as in the measurement of adhesive strength A after ultraviolet irradiation in the presence of oxygen described above. The peel speed was 300 mm/min. Measurements were performed on three test pieces, and the average of the values for the three specimens was taken as adhesive strength B of the dicing tape 10 after ultraviolet irradiation in the absence of oxygen.

In addition, the ratio A/B of the adhesive strength A after UV irradiation in the presence of oxygen to the adhesive strength B after UV irradiation in the absence of oxygen of the adhesive layer 2 of the dicing tape 10 was calculated using the above adhesive strength measurements.

5.2 Measurement of Shear Viscosity of Die Bonding Film (Adhesive Layer) 3 at 80°C For each of the die bonding films (adhesive layers) 3 formed from the solutions of adhesive compositions 3(a) to 3(d), the shear viscosity at 80°C was measured by the following method.
A laminate was produced by laminating multiple sheets of die-bonding film (adhesive layer) 3 from which the release liner had been removed at 70°C to a total thickness of 200 to 210 μm. The laminate was then punched out in the thickness direction to a size of 10 mm x 10 mm to prepare a measurement sample. Subsequently, using an ARES dynamic viscoelasticity measuring device (manufactured by Rheometric Scientific F.E.), an 8 mm diameter circular aluminum plate jig was attached, and the measurement sample was then set. While applying a 5% strain to the measurement sample at 35°C, the shear viscosity was measured while the temperature of the measurement sample was increased at a heating rate of 5°C/min, and the shear viscosity at 80°C was determined.

Tables 1 to 9 show the configurations and the above-mentioned measurement results for the dicing tapes 10 and dicing die bond films 20 produced in Examples 1 to 26 and Comparative Examples 1 to 7.

6. Mounting evaluation of dicing tape The dicing tapes 10 produced in Examples 1 to 26 and Comparative Examples 1 to 7 were evaluated in the form of dicing die bond films 20 (DDF (a) to DDF (gg)) by the methods shown below.

6.1 Cleavability of Die Bond Film (Adhesive Layer) First, a semiconductor wafer (silicon mirror wafer, thickness 750 μm, outer diameter 12 inches) W was prepared, and a commercially available backgrind tape was attached to one surface. Next, using a stealth dicing laser saw (device name: DFL7361) manufactured by Disco Corporation, laser light was irradiated from the side of the semiconductor wafer W opposite to the side where the backgrind tape was attached along the lattice-shaped dicing lines under the following conditions so that the size of the semiconductor chip 30a after cleavage would be 4.6 mm × 7.2 mm, thereby forming a modified region 30b at a predetermined depth in the semiconductor wafer W.

Laser irradiation conditions (1) Laser oscillator type: Semiconductor laser pumped Q-switched solid-state laser
(2) Wavelength: 1342nm
(3) Oscillation type: Pulse
(4) Frequency: 90 kHz
(5) Output: 1.7W
(6) Moving speed of semiconductor wafer mounting table: 700 mm/sec

Next, a backgrinding device (device name: DGP8761) manufactured by Disco Corporation was used to grind and thin the 750 μm thick semiconductor wafer W on which the modified region 30b was formed and held by the backgrinding tape, thereby obtaining individual semiconductor chips 30a with a thickness of 30 μm. Next, a cool expansion process was performed using the following method to evaluate the cleavability of the die bond film (adhesive layer). Specifically, a laminating machine (machine name: DFM2800) manufactured by Disco Corporation was used to bond the dicing die bond film 20 to the semiconductor chip 30a at a laminating temperature of 70°C and a laminating speed of 10 mm/sec so that the die bond film 3 exposed by peeling off the release liner from the dicing die bond film 20 produced in each example and comparative example was adhered to the side of the 30 μm-thick semiconductor chip 30a opposite to the side to which the backgrind tape was attached. A ring frame (wafer ring) 40 was then attached to the exposed portion of the adhesive layer 2 at the outer edge of the dicing tape 10, and the backgrind tape was then peeled off. Note that the dicing die bond film 20 was attached to the semiconductor chip 30a so that the MD direction of the base film 1 coincided with the vertical direction of the grid-like dividing lines of the semiconductor chip 30a (the TD direction of the base film 1 coincided with the horizontal direction of the grid-like dividing lines of the semiconductor chip 30a).

The laminate (semiconductor wafer 30/die bond film 3/adhesive layer 2/base film 1) containing the semiconductor chip 30a held in the ring frame (wafer ring) 40 was fixed to an expanding device (device name: DDS2300 Fully Automatic Die Separator) manufactured by Disco Corporation. Next, the dicing tape 10 (adhesive layer 2/base film 1) of the dicing die bond film 20 containing the semiconductor chip 30a was cool-expanded under the following conditions to cleave the die bond film 3. This resulted in a semiconductor chip 30a with a die bond film (adhesive layer) 3. In this example, the cool-expanding process was performed under the following conditions; however, the cool-expanding process may be performed after adjusting the expansion conditions (such as the "expansion speed" and "expansion amount") appropriately depending on the physical properties and temperature conditions of the base film 1.

・Conditions for the cool expansion process: Temperature: -15°C, Cooling time: 80 seconds,
Expanding speed: 300 mm/sec
Expanded amount: 11 mm
(4) Waiting time: 0 seconds

The die bond film (adhesive layer) 3 after cool expansion was observed from the front side of the semiconductor chip 30a at 200x magnification using an optical microscope (model: VHX-1000) manufactured by Keyence Corporation, to count the number of uncleaved edges among the edges intended to be cleaved. The cleavage rate (%) was then calculated as the percentage of the number of cleaved edges to the total number of edges intended to be cleaved, based on the total number of edges intended to be cleaved and the total number of uncleaved edges. Observation using the optical microscope was performed on all semiconductor chips 30a with die bond film 3a. The cleavability of the die bond film (adhesive layer) 3 was evaluated according to the following criteria, and a rating of B or higher was deemed to be good cleavability.

A: The fracture rate was 95% or more and 100% or less.
B: The fracture rate was 90% or more and less than 95%.
C: The fracture rate was 85% or more and less than 90%.
D: The fracture rate was less than 85%.

6.2 Confirmation of Presence or Absence of Peeling of Edge Portion of Die Bonding Film and Calculation of Proportion of Area S1 of Edge Portion of Die Bonding Film Peeled from Pressure-Sensitive Adhesive Layer After releasing the above-mentioned cool expansion state, an expansion device manufactured by Disco Corporation (device name: DDS2300 Fully Automatic Die Separator) was used again, and an ordinary temperature expansion step was carried out under the following conditions in its heat expander unit.

・ Temperature condition for room temperature expansion process: 23°C,
Expanding speed: 30 mm/sec
Expanded amount: 9 mm
(4) Waiting time: 15 seconds

Next, while maintaining the expanded state, the dicing tape 10 was adsorbed onto the suction table, and the suction table was lowered along with the workpiece while maintaining the adsorption by the suction table. Then, under the following conditions, a heat shrink process was carried out, causing the circumferential portion of the dicing tape 10 outside the semiconductor chip 30a holding area to heat shrink (heat shrink).

Heat shrink process conditions: Hot air temperature: 200°C,
Air volume: 40L/min,
Distance between hot air outlet and dicing tape 10: 20 mm,
Stage rotation speed: 7°/sec

Next, after the dicing tape 10 was released from the suction table, the state of the die bond film (adhesive layer) 3 peeling from the pressure-sensitive adhesive layer 2 of the dicing tape 10 was observed at 50x magnification from the back side (substrate film 1 side) of the semiconductor chip 30a using an optical microscope (model: VHX-1000) manufactured by Keyence Corporation. The state of peeling of the die bond film (adhesive layer) 3 was observed to be approximately the same for all positions of the semiconductor chip 30a, so the presence or absence of peeling was confirmed for a predetermined 20 semiconductor chips 30a with die bond film 3a located in the center of the semiconductor wafer 30. The percentage of the above area S1 was calculated using the following method. First, three were randomly selected from the 20 semiconductor chips 30a with die bond film 3a, and the image observed for each was binarized using the image processing software "ImageJ" (available from https://imagej.Nih.gov/ij/) to separate the portion corresponding to the area S1 and the portion corresponding to the area S2. Using the binarized image-processed image, the ratio of the area S1 of the edge portion of the small piece of die bond film 3a peeled from the adhesive layer 2 to the entire area (= S1 + S2) of the small piece of die bond film 3a was calculated as the average value of the three measurements.

6.3 Pick-up property An evaluation sample was prepared by irradiating ultraviolet (UV) rays with a central wavelength of 367 nm from the base film 1 side of the dicing tape 10 holding the semiconductor chips 30 a with the die bond film (adhesive layer) 3 a that had been cleaved and separated by the above-mentioned expanding process, so that the integrated light amount was 150 mJ/cm ² at an irradiation intensity of 70 mW/cm ² to harden the pressure-sensitive adhesive layer 2.

Next, a pickup test of the semiconductor chip 30a with the die bond film 3a was conducted using a device with a pickup mechanism (device name: Die Bonder DB-830P) manufactured by Fasford Technology Co., Ltd. (formerly Hitachi High-Technologies Corporation). The pickup collet size was 4.5 x 7.1 mm, the number of push-up pins was 12, and the pickup conditions were a push-up speed of 5 mm/sec and a push-up height of 300 μm, 200 μm, and 150 μm. The number of samples in the pickup trial was 20 individual chips at predetermined positions, which were picked up consecutively and the number successfully picked up was counted. The pickup ability of the semiconductor chip 30a with the die bond film 3a at each push-up height was evaluated according to the following criteria.

A: 20 chips were picked up consecutively, and the number of chips for which no chip breakage or pick-up errors occurred (number of successfully picked-up chips) was 19 or more and 20 or less (success rate of 95% or more and 100% or less).
B: 20 chips were picked up consecutively, and the number of chips that did not break or fail to be picked up (number of successfully picked up chips) was 17 or more and less than 19 (success rate of 85% or more and less than 95%).
C: 20 chips were picked up consecutively, and the number of chips without chip breakage or pick-up errors (number of successfully picked-up chips) was less than 17 (success rate less than 85%).

In terms of the overall evaluation of the above pickup test, it was determined that the smaller the push-up height of the push-up pin that resulted in an A or B rating for the number of semiconductor chips 30a with die bond film 3a successfully picked up, the better the pickup performance when using that dicing tape 10.

6.3. Evaluation Results Tables 10 to 18 show the results of mounting evaluation of each dicing tape 10 produced in Examples 1 to 26 and Comparative Examples 1 to 7 in the form of a dicing die bond film 20 (DDF(a) to DDF(gg)).

As shown in Tables 10 to 16, the dicing die bond films 20 (DDF(a) to DDF(z)) of Examples 1 to 26, which were produced using dicing tape 10 comprising substrate films 1(a) to 1(h) and pressure-sensitive adhesive layers 2 containing pressure-sensitive adhesive compositions 2(a) to 2(p) that satisfy the requirements of the present invention and which satisfy the requirements of adhesive strength A after ultraviolet irradiation in the presence of oxygen and adhesive strength B after ultraviolet irradiation in the absence of oxygen, were subjected to the manufacturing process of a semiconductor device. When the die bond film 3 was subjected to cool expansion, the die bond film 3 was successfully cleaved, and the edge of the cleaved die bond film 3a was This results in a state in which the edge portion (surrounding area on all four sides) is appropriately peeled from the adhesive layer 2 of the dicing tape 10, and the adhesive strength A after irradiation with ultraviolet light in the presence of oxygen is significantly reduced. As a result, during pick-up, the edge portion of the die bond film 3 in the peeled state from the adhesive layer is significantly suppressed from strongly re-adhering to the adhesive layer 2 of the dicing tape 10 after irradiation with ultraviolet light. This allows the semiconductor chip 30a with the dicing die bond film 3a to be pushed up and peeled from the adhesive layer 2 more smoothly from the edge portion, and it was confirmed that favorable results were also obtained in the evaluation of pick-up performance.

When the Examples were compared in detail, it was found that the dicing die bond films 20 of Examples 2 to 4, 6, 8, 10, 11, 14 to 16, 21, 22, and 24 to 26 were able to achieve high levels of both the cleavability and pick-up properties of the die bond film 3, and were particularly excellent. In other words, the cleavage rate of the die bond film 3 in the cool expansion process was extremely good, and furthermore, the yield in the pick-up test, in which the amount of push-up height of the push-up pin was small, was also extremely good.

In the dicing die bond films 20 of Examples 1 and 7, the average value (Y _MD +Y TD )/2 of the elastic modulus at 5% elongation in the MD direction and TD direction of the base film 1 (a) and 1 ( _g ) at 0 ° C. is close to the lower limit of the range of the present invention, and therefore the cleavability and pick-up property of the die bond film 3 were slightly inferior compared to the dicing die bond films 20 of Examples 2 to 4, 6, and 8. On the other hand, in the dicing die bond film 20 of Example 5, the average value (Y _MD +Y _TD )/2 of the elastic modulus at 5% elongation in the MD direction and TD direction of the base film 1 (e) at 0 ° C. is close to the upper limit of the range of the present invention, and therefore the pick-up property was slightly inferior compared to the dicing die bond films 20 of Examples 2 to 4, 6, and 8.

In the dicing die bond films 20 of Examples 9 and 18, the hydroxyl value of the acrylic adhesive polymer (A) of the pressure-sensitive adhesive composition 2( b ) and the pressure-sensitive adhesive composition 2(k) is close to the lower limit of the range of the present invention, and the amount of polyisocyanate-based crosslinking agent added is also the lower limit of the range of the present invention. Therefore, compared with the dicing die bond films 20 of Examples 2, 10, and 11, the proportion of the area S1 of the edge portion (shaded portion) of the die bond film 3a of the small piece peeled off from the pressure-sensitive adhesive layer 2 during cool expansion was slightly smaller, that is, the contribution of the effect of reducing the adhesive strength after irradiation with ultraviolet light in the presence of oxygen was small, and the pickup properties were slightly inferior.

The dicing die bond films 20 of Examples 12, 17, and 19 were prepared using the pressure-sensitive adhesive composition 2 ( e ) , the hydroxyl value of the acrylic adhesive polymer (A) or the acrylic adhesive polymer (E) of the pressure-sensitive adhesive composition 2(j) and the pressure-sensitive adhesive composition 2(l) is close to the lower limit of the range of the present invention, and the amount of the polyisocyanate crosslinking agent added is also close to or is the upper limit of the range of the present invention, and the amount of the polyisocyanate crosslinking agent added in the pressure-sensitive adhesive composition 2(a) and the equivalent ratio (-NCO/-OH) of the isocyanate group (-NCO) of the polyisocyanate crosslinking agent to the hydroxyl group (-OH) of the acrylic adhesive polymer are also close to the upper limit of the range of the present invention. Therefore, compared with the dicing die bond films 20 of Examples 2, 10, and 11, the proportion of the area S1 of the edge portion (shaded portion) of the die bond film 3a of the small piece peeled from the pressure-sensitive adhesive layer 2 during cool expanding was slightly larger, and the effect of reducing the adhesive strength after irradiation with ultraviolet light in an oxygen atmosphere was gradually suppressed due to the influence of the increased re-fixing area, and the pick-up property was slightly inferior. Moreover, in the dicing die bond films 20 of Examples 12 and 19, the breakability of the die bond film 3 was also slightly inferior.

In the dicing die bond film 20 of Example 13, the hydroxyl value of the acrylic adhesive polymer ( B ) of the pressure-sensitive adhesive composition 2 ( f ) is close to the upper limit of the range of the present invention, and the amount of polyisocyanate-based crosslinking agent added is the lower limit of the range of the present invention. Compared with the dicing die bond films 20 of Examples 2 and 14 to 17, the proportion of the area S1 of the edge portion (shaded portion) of the small piece of die bond film 3a peeled off from the pressure-sensitive adhesive layer 2 during cool expansion was slightly smaller, that is, the contribution of the adhesive strength reducing effect after irradiation with ultraviolet light in the presence of oxygen was small, and the pickup property was slightly inferior.

The dicing die bond film 20 of Example 20 had an adhesive strength after ultraviolet irradiation in the presence of oxygen that was close to the upper limit of the range of the present invention, and had slightly inferior pickup properties compared to the dicing die bond films 20 of Examples 2, 21, and 22.

In contrast, as shown in Tables 17 and 18, the dicing die bond films 20 (DDF(aa) to DDF(gg)) of Comparative Examples 1 to 7, which were produced using dicing tape 10 that did not satisfy at least one of the requirements for the base film 1, the properties of the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer 2, namely, adhesive strength A after irradiation with ultraviolet light in the presence of oxygen and adhesive strength B after irradiation with ultraviolet light in the absence of oxygen, were found to have results inferior to the dicing die bond films 20 (DDF(a) to DDF(z)) of Examples 1 to 26 in either the evaluation of the cleavability of the die bond film 3 in the cool expand step or the pick-up ability in the pick-up step.

Specifically, for the dicing die bond film 20 (DDF (aa)) of Comparative Example 1, the average value of the elastic modulus at 5% elongation in the MD direction and the TD direction of the base film 1 (i) of the dicing tape 10 at 0°C (Y _MD +Y _TD ) / 2, and the equivalent ratio (-NCO / -OH) of the isocyanate group (-NCO) of the polyisocyanate crosslinking agent in the pressure-sensitive adhesive composition 2 (q) and the hydroxyl group (-OH) of the acrylic pressure-sensitive adhesive polymer is below the lower limit of the range of the present invention, the die bond film 3 made of the adhesive composition 3 (c) has poor cleavability in the cool expand step, and even in the cleaved die bond film 3a, the edge portion does not show a state where it has been peeled from the pressure-sensitive adhesive layer 2 (no peeling was observed), and compared to the dicing die bond film 20 (DDF (y)) of Example 25 using the die bond film 3 made of the adhesive composition 3 (c), it was confirmed that the die bond film 3 made of the adhesive composition 3 (c) was inferior in both the cleavability and pick-up properties.

Similarly, for the dicing die bond films 20 (DDF(bb)) and (DDF(cc)) of Comparative Examples 2 and 3, the average values of the elastic moduli at 5% elongation in the MD direction and the TD direction at 0° C. of the base films 1(j) and 1(l) of the dicing tape 10 (Y _MD +Y _TD ) / 2, and the equivalent ratio (-NCO / -OH) of the isocyanate group (-NCO) of the polyisocyanate crosslinking agent in the pressure-sensitive adhesive composition 2 (q) and the hydroxyl group (-OH) of the acrylic pressure-sensitive adhesive polymer are below the lower limit of the range of the present invention, the die bond film 3 made of the adhesive composition 3 (a) has poor cleavability in the cool expand step, and even in the cleaved die bond film 3a, a state in which it has been peeled from the pressure-sensitive adhesive layer 2 is not formed at the edge portion (no peeling is observed), for example, compared with the dicing die bond films 20 (DDF (a) to DDF (q)), (DDF (t) to DDF (w)) of Examples 1 to 17 and 20 to 23, it was confirmed that the die bond film 3 made of the adhesive composition 3 (a) has poor cleavability and pick-up properties.

Furthermore, for the dicing die bond film 20 (DDF(dd)) of Comparative Example 4, the pressure-sensitive adhesive composition 2(a) of the dicing tape 10 satisfies the requirements of the present invention, but the average value (Y _MD +Y _TD )/2 of the elastic modulus at 5% elongation in the MD direction and the TD direction of the base film 1(i) at 0 ° C. is below the lower limit of the range of the present invention, and the adhesive strength A of the pressure-sensitive adhesive layer 2 after irradiation with ultraviolet light in the presence of oxygen exceeds the upper limit of the range of the present invention. Therefore, the cleavability of the die bond film 3 made of the adhesive composition 3(a) in the cool expand step is poor, and although the cleaved die bond film 3a had a small amount of peeling from the pressure-sensitive adhesive layer 2 at its four corners, the adhesive strength A after irradiation with ultraviolet light in the presence of oxygen was large. For example, compared to the dicing die bond film 20 (DDF(g)) of Example 7, it was confirmed that the die bond film 3 made of the adhesive composition 3(a) was inferior in both the evaluation of the cleavability and the pick-up ability.

Furthermore, for the dicing die bond film 20 (DDF (ee)) of Comparative Example 5, the base film 1 (b) of the dicing tape 10 satisfies the requirements of the present invention, but the equivalent ratio (-NCO/-OH) of the isocyanate group (-NCO) of the polyisocyanate crosslinking agent in the pressure-sensitive adhesive composition 2 (s) and the hydroxyl group (-OH) of the acrylic pressure-sensitive adhesive polymer is below the lower limit of the range of the present invention. Therefore, although the die bond film 3 made of the adhesive composition 3 (a) had good cleavability in the cool expand process, the cleaved die bond film 3a did not show a state where it was peeled from the pressure-sensitive adhesive layer 2 at its edge portion (no peeling was observed), for example, compared to the dicing die bond film 20 (DDF (i)) of Example 9, it was confirmed that the result was slightly inferior in the evaluation of pickup properties.

Furthermore, with regard to the dicing die bond film 20 (DDF(ff)) of Comparative Example 6, the properties of the base film 1(b) and the pressure-sensitive adhesive composition 2(t) of the dicing tape 10 satisfy the requirements of the present invention,
Since the adhesive strength A of the adhesive layer 2 after irradiation with ultraviolet light under oxygen exceeds the upper limit of the range of the present invention, the die bond film 3 made of the adhesive composition 3(a) has good cleavability in the cool expansion process, and the edge portions (surrounding portions on all four sides) of the cleaved die bond film 3a are moderately peeled from the adhesive layer 2 of the dicing tape 10. However, the adhesive strength A after irradiation with ultraviolet light under oxygen is large, and it was confirmed that the result was inferior in the evaluation of pick-up properties compared to, for example, the dicing die bond film 20 (DDF(p)) of Example 16.

Furthermore, the dicing die bond film 20 (DDF(gg)) of Comparative Example 7 satisfies the requirements of the present invention for the adhesive strength A after ultraviolet irradiation in the presence of oxygen and the adhesive strength B after ultraviolet irradiation in the absence of oxygen of the base film 1(b) and adhesive layer 2 of the dicing tape 10, but the amount of polyisocyanate-based crosslinking agent added in adhesive composition 2(u) and the equivalent ratio (-NCO/-OH) of the isocyanate group (-NCO) of the polyisocyanate-based crosslinking agent to the hydroxyl group (-OH) of the acrylic adhesive polymer exceed the upper limit of the range of the present invention. Therefore, the die bond film 3 made of adhesive composition 3(a) Although the die bond film 3a could be cut at a level that did not pose any problems in the cool expanding process, the cut die bond film 3a was peeled excessively and irregularly from the adhesive layer 2 of the dicing tape 10 from its edge portions (surrounding portions on all four sides) toward the center, and when picked up, the area of the die bond film 3a in a state that had been peeled from the adhesive layer that re-adhered to the adhesive layer 2 after ultraviolet irradiation of the dicing tape 10 became too large, and it was confirmed that the pick-up ability was inferior to that of, for example, the dicing die bond film 20 (DDF(l)) of Example 12. Furthermore, after the expanding process, cracks in the adhesive layer 2 and peeling from the base film 1 were observed in some parts.

1...base film,
2...adhesive layer,
3, 3a1, 3a2... die bond film (adhesive layer, adhesive film),
4...Stainless steel plate (SUS304 BA plate),
5...Flat cross stage,
6...actuator,
7...load cell,
8...Rotating stage,
9...Semiconductor chip with die bond film,
10... dicing tape,
20... dicing die bond film,
W, 30...semiconductor wafer,
30a, 30a1, 30a2...semiconductor chips,
30b...modified region (fractured region in FIGS. 7(c) to (f) and FIGS. 8(a) and (b)),
30c...semiconductor wafer cleaving line 31...semiconductor wafer center 32...semiconductor wafer left portion 33...semiconductor wafer right portion 34...semiconductor wafer upper portion 35...semiconductor wafer lower portion 40...ring frame (wafer ring),
41... Holder,
50...suction collet,
60...Push-up pin (needle)
70, 80... Semiconductor device 71, 81... Support substrate for mounting semiconductor chip 72... External connection terminal,
73...terminal,
74, 84...wires 75, 85...sealing material 76...support member

Claims (9)

A dicing tape comprising a substrate film and a pressure-sensitive adhesive layer on the substrate film, the pressure-sensitive adhesive layer containing an active energy ray-curable pressure-sensitive adhesive composition,
When the elastic modulus of the base film at 5% elongation in the MD direction (the machine direction during film formation of the base film) at 0°C is defined as Y _MD and the elastic modulus of the base film at 5% elongation in the TD direction (the direction perpendicular to the MD direction) at 0°C is defined as Y _TD , the average value of the elastic moduli at 5% elongation (Y _MD +Y _TD )/2 is in the range of 165 MPa or more and 260 MPa or less,
The active energy ray-curable pressure-sensitive adhesive composition comprises an acrylic pressure-sensitive adhesive polymer having an active energy ray-reactive carbon-carbon double bond and a hydroxyl group, a photopolymerization initiator, and a polyisocyanate-based crosslinking agent that undergoes a crosslinking reaction with the hydroxyl group;
the acrylic adhesive polymer has a hydroxyl value in the range of 12.0 mgKOH/g or more and 40.5 mgKOH/g or less , the polyisocyanate crosslinking agent is contained in an amount in the range of 2.4 parts by mass or more and 7.0 parts by mass or less relative to 100 parts by mass of the acrylic adhesive polymer, and an equivalent ratio (-NCO/-OH) of an isocyanate group (-NCO) of the polyisocyanate crosslinking agent to a hydroxyl group (-OH) of the acrylic adhesive polymer is adjusted in the range of 0.14 or more and 1.32 or less,
The pressure-sensitive adhesive layer of the dicing tape has an adhesive strength A (ultraviolet ray cumulative dose: 150 mJ/ ^m2 , peel angle: 90°, peel speed: 300 mm/min) of 3.50 N/25 mm or less after ultraviolet irradiation in the presence of oxygen to a stainless steel plate (SUS304 BA plate) at 23°C (ultraviolet ray cumulative dose: 150 mJ/ ^{m2, peel angle: 90°, peel speed: 300 mm/min) in the range of 0.25 N/25 mm or more and 0.70 N/25 mm or less after ultraviolet irradiation in the absence of oxygen to a stainless steel plate (SUS304 BA plate) at 23°C (ultraviolet ray cumulative dose: 150 mJ/m2} , peel angle: 90°, peel speed: 300 mm/min).
Dicing tape. The dicing tape of claim 1, wherein the base film is a resin film composed of a resin composition containing a resin (IO) made of an ionomer of an ethylene-unsaturated carboxylic acid copolymer and a polyamide resin (PA). The dicing tape according to claim 1 or 2, wherein the active energy ray-curable adhesive composition contains at least three types of photopolymerization initiators: (a) an α-aminoalkylphenone-based photopolymerization initiator, (b) an alkylphenone-based photopolymerization initiator other than an α-aminoalkylphenone-based photopolymerization initiator, and (c) an acylphosphine oxide-based photopolymerization initiator. The dicing tape of claim 3, wherein the respective contents of the α-aminoalkylphenone photopolymerization initiator (a), the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and the acylphosphine oxide photopolymerization initiator (c) are, relative to 100 parts by mass of the acrylic adhesive polymer, in the range of 0.8 parts by mass to 5.0 parts by mass of the α-aminoalkylphenone photopolymerization initiator (a), in the range of 0.2 parts by mass to 5.0 parts by mass of the alkylphenone photopolymerization initiator other than the α-aminoalkylphenone photopolymerization initiator (b), and in the range of 0.2 parts by mass to 2.0 parts by mass of the acylphosphine oxide photopolymerization initiator (c). The dicing tape according to any one of claims 1 to 4, wherein the ratio A/B of the adhesive strength A after ultraviolet irradiation in the presence of oxygen to the adhesive strength B after ultraviolet irradiation in the absence of oxygen is in the range of 3.00 to 5.00. The dicing tape according to any one of claims 1 to 5 is used to expand (stretch) a sheet-like laminate in which a die bond film and multiple individual semiconductor chips are sequentially laminated on the adhesive layer at a temperature of -30°C to 0°C, and to cleave the die bond film to match the shape of the individual semiconductor chips. The dicing tape according to claim 6, wherein when the dicing tape to which the sheet-like laminate is attached is expanded (stretched) at a temperature in the range of -30°C or higher and 0°C or lower, and the die bond film is cut to match the shape of the individual semiconductor chip, edge portions (surrounding portions on all four sides) of the die bond film are peeled off from the pressure-sensitive adhesive layer. 8. The dicing tape according to claim 6 or 7, wherein the die bond film cleaved to match the shape of the individual semiconductor chip has an area ratio of the edge portion (four-sided surrounding portion) of the die bond film peeled off from the pressure- sensitive adhesive layer in the range of 10% or more and 45% or less of the entire area of the cleaved die bond film. A method for manufacturing a semiconductor device using the dicing tape described in any one of claims 1 to 8.