JP7633008B2 - Dicing tape and dicing die bond film - Google Patents

Description

The present invention relates to a dicing tape and a dicing die bond film.

2. Description of the Related Art Conventionally, in the manufacture of semiconductor devices, it is known to use a dicing tape or a dicing die bond film to obtain a semiconductor chip for die bonding.
The dicing tape is constructed by laminating an adhesive layer on a base layer, and the dicing die bond film is constructed by releasably laminating a die bond layer on the adhesive layer of the dicing tape.

As a method for obtaining a semiconductor chip (die) for die bonding using the dicing die bond film, a method having the following steps is known: a half-cut process for forming a groove in the semiconductor wafer to process the semiconductor wafer into a chip (die) by a fracturing process; a back-grind process for grinding the semiconductor wafer after the half-cut process to reduce its thickness; a mounting process for attaching one surface (e.g., the surface opposite to the circuit surface) of the semiconductor wafer after the back-grind process to a die-bonding layer and fixing the semiconductor wafer to the dicing tape; an expanding process for expanding the space between the half-cut semiconductor chips; a kerf maintaining process for maintaining the space between the semiconductor chips; a pick-up process for peeling off the die-bonding layer and the adhesive layer to remove the semiconductor chip with the die-bonding layer attached; and a die-bonding process for bonding the semiconductor chip with the die-bonding layer attached to an adherend (e.g., a mounting board, etc.).
In the kerf maintaining step, hot air (e.g., 100 to 130° C.) is applied to the dicing tape to thermally shrink the dicing tape, and then the dicing tape is cooled and solidified, thereby maintaining the distance (kerf) between adjacent cleaved semiconductor chips.
In the expanding step, the die bond layer is cleaved into pieces having sizes corresponding to the sizes of the individual semiconductor chips.

In a method for obtaining semiconductor chips for die bonding using the above-mentioned dicing die bond film, Patent Document 1 discloses that by using a dicing tape with specific physical properties (a dicing tape with an initial elastic modulus of 200 MPa to 380 MPa at -10°C and a Tan δ (loss elastic modulus/storage elastic modulus) of 0.080 to 0.3 at -10°C) and performing the expansion process under low-temperature conditions of -15 to 5°C, the breakability (e.g., ease of breakability and uniform breakability) of the semiconductor wafer into multiple semiconductor chips can be improved in the expansion process.

JP 2015-185591 A

Meanwhile, the size required for a semiconductor chip varies depending on the application.
Furthermore, the smaller the required size of the semiconductor chip, the greater the number of grooves (fracturing lines) that must be formed in the semiconductor wafer when a semiconductor wafer of the same size is expanded and diced into multiple semiconductor chips. The greater the number of fracturing lines, the more the dicing tape or dicing die bond film needs to be stretched in order to sufficiently widen the gap between the semiconductor chips in the expanding process.
Therefore, depending on the physical properties of the dicing tape or dicing die bond film, the dicing tape or dicing die bond film may not be stretched sufficiently even when it is necessary to stretch it further, and as a result, the distance between the semiconductor chips may not be sufficiently widened in the expanding step. In other words, the semiconductor wafer may not be well cut into a plurality of semiconductor chips.
Furthermore, in the kerf maintaining step, the kerf may not be maintained sufficiently.
However, even when it is necessary to stretch the dicing tape or dicing die bond film more in the expanding process, i.e., when the number of cutting lines is relatively large, sufficient consideration has not been given to achieving good cutting from the cut semiconductor wafer into multiple semiconductor chips.
Furthermore, in the kerf maintaining step, sufficient consideration has not been given to maintaining the kerf sufficiently.

The present invention aims to provide a dicing tape and dicing die bond film that can effectively cleave a semiconductor wafer into multiple semiconductor chips and adequately maintain the kerf, even when the number of cleaving lines is relatively large.

After extensive research, the inventors discovered that by using a dicing tape and dicing die bond film with a tensile storage modulus within a specified range at -10°C, it is possible to perform good cleavage from a semiconductor wafer into multiple semiconductor chips and to adequately maintain the kerf, even when the number of cleavage lines is relatively large, and thus came up with the present invention.

That is, the dicing tape according to the present invention is
A dicing tape having a pressure-sensitive adhesive layer laminated on a base layer,
The tensile storage modulus at -10°C is 50 MPa or more and 250 MPa or less.

According to this configuration, the tensile storage modulus of the dicing tape at −10° C. is 50 MPa or more and 250 MPa or less, so that the dicing tape has appropriate elasticity.
Therefore, when the dicing tape is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into a plurality of semiconductor chips, the dicing tape can be stretched further.
As a result, even if the number of cutting lines is relatively large, the semiconductor wafer can be cut satisfactorily into a plurality of semiconductor chips.
Also, the calf can be adequately maintained.

In the dicing tape,
The loss coefficient at -10°C is preferably 0.07 or more and 0.18 or less.

According to this configuration, the loss factor at −10° C. is 0.07 or more and 0.18 or less, so that the dicing tape has appropriate hardness in addition to appropriate elasticity.
Therefore, when the dicing tape is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into multiple semiconductor chips, not only can the dicing tape be stretched more, but breakage of the dicing tape when stretched can be relatively suppressed.
As a result, even when the number of cutting lines is relatively large, the semiconductor wafer can be cut satisfactorily into multiple semiconductor chips, and the kerf can be adequately maintained, while breakage of the dicing tape during cutting can be relatively suppressed.

In the dicing tape,
The breaking elongation at -10°C is preferably 450% or more and 600% or less.

According to this configuration, the breaking elongation at -10°C is 450% or more and 600% or less, so that the dicing tape has appropriate hardness in addition to appropriate elasticity.
Therefore, when the dicing tape is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into multiple semiconductor chips, not only can the dicing tape be stretched more, but breakage of the dicing tape when stretched can be relatively suppressed.
As a result, even when the number of cutting lines is relatively large, the semiconductor wafer can be cut satisfactorily into multiple semiconductor chips, and the kerf can be sufficiently maintained, while breakage of the dicing tape during cutting can be relatively suppressed.

The dicing die bond film according to the present invention is
a dicing tape having a pressure-sensitive adhesive layer laminated on a base layer;
A die bond layer laminated on the pressure-sensitive adhesive layer of the dicing tape,
The tensile storage modulus at -10°C is 50 MPa or more and 250 MPa or less.

According to this configuration, when the dicing tape is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into a plurality of semiconductor chips, the dicing tape can be stretched further.
As a result, even if the number of cutting lines is relatively large, the semiconductor wafer can be cut satisfactorily into a plurality of semiconductor chips.
Also, the calf can be adequately maintained.

The present invention provides a dicing tape and dicing die bond film that can effectively cleave a semiconductor wafer into multiple semiconductor chips and adequately maintain the kerf, even when the number of cleaving lines is relatively large.

1 is a cross-sectional view showing a configuration of a dicing tape according to an embodiment of the present invention. 1 is a cross-sectional view showing a configuration of a dicing die bond film according to one embodiment of the present invention. 1A to 1C are cross-sectional views each showing a schematic view of a half-cut process in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic view of a half-cut process in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of a back grinding process in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of a back grinding process in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic view of a mounting step in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic view of a mounting step in a manufacturing method of a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of an expanding step performed at a low temperature in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of an expanding step performed at a low temperature in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of an expanding step performed at a low temperature in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of an expanding step at room temperature in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a schematic diagram of an expanding step at room temperature in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a kerf maintaining step in a method for manufacturing a semiconductor integrated circuit. 1A to 1C are cross-sectional views each showing a pickup step in a method for manufacturing a semiconductor integrated circuit.

One embodiment of the present invention is described below.

[Dicing tape]
As shown in FIG. 1, the dicing tape 10 according to this embodiment is a dicing tape in which a pressure-sensitive adhesive layer 2 is laminated on a base layer 1, and has a tensile storage modulus at −10° C. of 50 MPa or more and 250 MPa or less.

As will be described in the Examples section below, since the tensile storage modulus of the dicing tape 10 at -10°C is 50 MPa or more and 250 MPa or less, it is possible to effectively cleave a semiconductor wafer (e.g., a semiconductor wafer having a diameter of 200 mm (8 inches) or more) into extremely small semiconductor chips having an area of 10 ^mm2 or less (e.g., a semiconductor chip having a roughly rectangular surface and a length of 4 mm and a width of 2 mm (area 8 ^mm2 )), such as those used in NAND memory controllers.

The present inventors speculate that the reason for this is as follows.
The size required for a semiconductor chip varies depending on the application. As described above, a semiconductor chip used in a NAND memory controller is extremely small with an area of 10 ^mm2 or less, whereas a semiconductor chip used in a NAND flash memory generally has an area of 40 mm2 or more (for example, a chip with a roughly rectangular surface, 12 ^mm long x 4 mm wide (area 48 ^mm2 ), or 10 mm long x 5 mm wide (area 50 ^mm2 )).
Here, when semiconductor wafers of the same size are cut into semiconductor chips, the smaller the size of the semiconductor chips after cutting, the narrower the spacing between the grooves (cutting lines) formed in the semiconductor wafer in the half-cut process, and therefore the greater the number of grooves formed in the semiconductor wafer.
Furthermore, when cleaving a semiconductor wafer having narrow groove spacing into multiple semiconductor chips, in order to ensure sufficient spacing between adjacent semiconductor chips, it is necessary to sufficiently stretch the dicing tape in the expanding process (e.g., expanding at room temperature (23±2°C)).
When a semiconductor wafer is cleaved into pieces with a relatively large area, such as semiconductor chips used in a NAND flash memory, the number of grooves formed in the semiconductor wafer is relatively small, so that even if a dicing tape having an initial elastic modulus at −10° C. of 200 MPa or more and 380 MPa or less, as described in Patent Document 1, is used, a sufficient distance can be provided between adjacent semiconductor chips.
However, when a semiconductor wafer is cleaved into tiny chips having a relatively small area such as those used in a NAND memory controller, the number of grooves formed in the semiconductor wafer is relatively large, and therefore, in the expanding step (e.g., expanding at room temperature), if a dicing tape having an initial elastic modulus of 200 MPa or more and 380 MPa or less at -10°C is used, the dicing tape may not be stretched sufficiently to create a sufficient gap between adjacent tiny chips. In particular, if the initial elastic modulus at -10°C is set to a value close to the upper limit of the above numerical range so that the dicing tape is less likely to break when expanding at room temperature, for example, the dicing tape becomes relatively hard and cannot be stretched sufficiently. Furthermore, when a dicing tape is used to divide a semiconductor wafer into multiple semiconductor chips, from the viewpoint of emphasizing fracturing ability, a relatively high value (for example, a value close to the upper limit of the numerical range described in Patent Document 1) is often selected for the initial elastic modulus of the dicing tape at -10°C in order to make it easier to apply stress to the dicing tape. However, even in such a case, the dicing tape becomes relatively hard as described above, and cannot be stretched sufficiently.
In contrast, the dicing tape 10 of this embodiment has a tensile storage modulus of 50 MPa or more and 250 MPa or less at -10°C, and has moderate elasticity, so it is considered that it can be stretched sufficiently even when cutting into extremely small chips such as semiconductor chips used in NAND memory controllers.
Therefore, it is believed that a sufficient gap can be created between adjacent ultra-small chips in the expanding process.

The tensile storage modulus at -10°C can be set to 50 MPa or more and 250 MPa or less by appropriately setting the material constituting the base layer 1, the layer structure of the base layer 1, and the thickness of the base layer 1.

The dicing tape 10 according to this embodiment preferably has a loss coefficient at -10°C of 0.07 or more and 0.18 or less.
This gives the dicing tape 10 an appropriate hardness in addition to an appropriate elasticity.
Therefore, when the dicing tape 10 is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into multiple semiconductor chips (particularly extremely small chips such as those used in NAND memory controllers), not only can the dicing tape 10 be stretched more, but breakage of the dicing tape 10 when stretched can be relatively suppressed.

The tensile storage modulus at -10°C and the loss factor at -10°C can be determined as follows.
Specifically, a dicing tape having a length of 40 mm (measurement length) and a width of 10 mm is used as a test piece, and the tensile storage modulus and loss modulus of the test piece are measured using a solid viscoelasticity measuring device (e.g., Model RSAIII, manufactured by Rheometric Scientific Co., Ltd.) under conditions of a frequency of 1 Hz, a strain of 0.1%, a heating rate of 10°C/min, and a chuck distance of 22.5 mm in a temperature range of -50 to 100°C. At that time, the tensile storage modulus at -10°C and the loss modulus at -10°C can be obtained by reading the value at -10°C, and the loss factor at -10°C can be obtained by dividing the value of the tensile storage modulus at -10°C by the value of the loss modulus at -10°C.
The measurement is carried out by pulling the test piece in the MD direction (resin flow direction).

The dicing tape 10 according to this embodiment preferably has a breaking elongation at -10°C of 450% or more and 600% or less.
This gives the dicing tape 10 an appropriate hardness in addition to an appropriate elasticity.
Therefore, when the dicing tape 10 is attached to a semiconductor wafer and expanded to cut the semiconductor wafer into multiple semiconductor chips (particularly extremely small chips such as those used in NAND memory controllers), not only can the dicing tape 10 be stretched more, but breakage of the dicing tape 10 when stretched can be relatively suppressed.

The breaking elongation at -10°C can be determined as follows.
Specifically, a dicing tape having a length of 120 mm (measurement length: L ₀ ) and a width of 10 mm was used as a test piece, and the test piece was pulled in the longitudinal direction using a tensile tester (Autograph AG-IS, manufactured by Shimadzu Corporation) under conditions of a temperature of -10°C, a chuck distance of 50 mm, and a tensile speed of 100 mm/min, and the length (L ₁ ) at which the test piece broke was measured.
Then, the breaking elongation E at −10° C. is calculated based on the following formula.

Breaking elongation E=(L ₁ −L ₀ )/L ₀ ×100

The substrate layer 1 supports the adhesive layer 2. The substrate layer 1 contains a resin. Examples of the resin contained in the substrate layer 1 include polyolefin, polyester, polyurethane, polycarbonate, polyether ether ketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamide, polyvinyl chloride, polyvinylidene chloride, polyphenyl sulfide, fluororesin, cellulose-based resin, and silicone resin.

Examples of polyolefins include homopolymers of α-olefins, copolymers of two or more types of α-olefins, block polypropylenes, random polypropylenes, and copolymers of one or more types of α-olefins with other vinyl monomers.

The homopolymer of an α-olefin is preferably an α-olefin homopolymer having 2 to 12 carbon atoms. Examples of such homopolymers include ethylene, propylene, 1-butene, and 4-methyl-1-pentene.

Examples of copolymers of two or more α-olefins include ethylene/propylene copolymers, ethylene/1-butene copolymers, ethylene/propylene/1-butene copolymers, ethylene/α-olefin copolymers having 5 to 12 carbon atoms, propylene/ethylene copolymers, propylene/1-butene copolymers, and propylene/α-olefin copolymers having 5 to 12 carbon atoms.

Examples of copolymers of one or more α-olefins with other vinyl monomers include ethylene-vinyl acetate copolymer (EVA).

The polyolefin may be one called an α-olefin thermoplastic elastomer, such as a combination of a propylene-ethylene copolymer and a propylene homopolymer, or a ternary copolymer of propylene, ethylene, and an α-olefin having 4 or more carbon atoms.
An example of a commercially available α-olefin-based thermoplastic elastomer is Vistamax 3980 (manufactured by ExxonMobil Chemical Corporation), which is a propylene-based elastomer resin.

The substrate layer 1 may contain one type of the above-mentioned resin, or may contain two or more types of the above-mentioned resin.
When the adhesive layer 2 contains an ultraviolet-curable adhesive described below, the base layer 1 is preferably configured to be ultraviolet-transmitting.

The substrate layer 1 may have a single layer structure or a laminated structure. The substrate layer 1 may be obtained by non-stretch molding or by stretch molding, but is preferably obtained by stretch molding. When the substrate layer 1 has a laminated structure, it is preferable that the substrate layer 1 has a layer containing an elastomer (hereinafter referred to as an elastomer layer) and a layer containing a non-elastomer (hereinafter referred to as a non-elastomer layer).
By providing the base layer 1 with an elastomer layer and a non-elastomer layer, the elastomer layer can function as a stress relaxation layer that relaxes tensile stress. In other words, the tensile stress generated in the base layer 1 can be made relatively small, so that the base layer 1 can be made relatively stretchable while having an appropriate hardness.
This improves the ease with which the semiconductor wafer can be broken into a plurality of semiconductor chips.
Furthermore, the base layer 1 can be prevented from breaking and being damaged during the expanding process in the cleaving step.
In this specification, the elastomer layer refers to a low modulus layer having a lower tensile storage modulus at room temperature than a non-elastomer layer. The elastomer layer may have a tensile storage modulus of 10 MPa or more and 100 MPa or less at room temperature, and the non-elastomer layer may have a tensile storage modulus of 200 MPa or more and 500 MPa or less at room temperature.

The elastomer layer may contain one kind of elastomer or may contain two or more kinds of elastomers, but preferably contains an α-olefin-based thermoplastic elastomer.
The non-elastomer layer may contain one type of non-elastomer or may contain two or more types of non-elastomers, but preferably contains metallocene PP, which will be described later.
When the base layer 1 has an elastomer layer and a non-elastomer layer, the base layer 1 is preferably formed in a three-layer structure (non-elastomer layer/elastomer layer/non-elastomer layer) having an elastomer layer as a central layer and non-elastomer layers on both opposing sides of the central layer (see Fig. 1). In Fig. 1, one non-elastomer layer is shown as a first resin layer 1a, the elastomer layer is shown as a second resin layer 1b, and the other non-elastomer layer is shown as a third resin layer 3c.

As described above, in the kerf maintaining step, hot air (e.g., 100 to 130°C) is applied to the dicing die bond film maintained in an expanded state at room temperature (e.g., 23°C) to thermally shrink the dicing die bond film, and then the dicing die bond film is cooled and solidified, so that the outermost layer of the base material layer 1 preferably contains a resin having a melting point close to the temperature of the hot air applied to the dicing tape. This allows the outermost layer melted by applying hot air to be solidified more quickly.
As a result, the kerf can be more sufficiently maintained in the kerf maintaining step.

When the base layer 1 has a laminated structure of an elastomer layer and a non-elastomer layer, the elastomer layer contains an α-olefin-based thermoplastic elastomer, and the non-elastomer layer contains a polyolefin such as metallocene PP described later, the elastomer layer preferably contains 50% by mass or more and 100% by mass or less of the α-olefin-based thermoplastic elastomer relative to the total mass of the elastomer forming the elastomer layer, more preferably 70% by mass or more and 100% by mass or less, even more preferably 80% by mass or more and 100% by mass or less, particularly preferably 90% by mass or more and 100% by mass or less, and optimally 95% by mass or more and 100% by mass or less. By containing the α-olefin-based thermoplastic elastomer in the above range, the affinity between the elastomer layer and the non-elastomer layer is increased, so that the base layer 1 can be extrusion molded relatively easily. In addition, the elastomer layer can act as a stress relaxation layer, so that the semiconductor wafer attached to the dicing tape can be efficiently cut.

When the base layer 1 has a laminated structure of an elastomer layer and a non-elastomer layer, the base layer 1 is preferably obtained by co-extrusion molding in which an elastomer and a non-elastomer are co-extruded to form a laminated structure of an elastomer layer and a non-elastomer layer. As the co-extrusion molding, any appropriate co-extrusion molding generally performed in the manufacture of films, sheets, etc. can be used. Among the co-extrusion moldings, it is preferable to use the inflation method or the co-extrusion T-die method, since the base layer 1 can be obtained efficiently and inexpensively.

When the base layer 1 having a laminated structure is obtained by co-extrusion molding, the elastomer layer and the non-elastomer layer are in contact with each other in a heated and molten state, so it is preferable that the melting point difference between the elastomer and the non-elastomer is small. Since the melting point difference is small, it is possible to prevent excessive heat from being applied to either the elastomer or the non-elastomer having a low melting point, thereby preventing the generation of by-products due to thermal deterioration of either the elastomer or the non-elastomer having a low melting point. It is also possible to prevent lamination defects between the elastomer layer and the non-elastomer layer due to an excessive decrease in viscosity of either the elastomer or the non-elastomer having a low melting point. The melting point difference between the elastomer and the non-elastomer is preferably 0°C or more and 70°C or less, more preferably 0°C or more and 55°C or less.
The melting points of the elastomer and the non-elastomer can be measured by differential scanning calorimetry (DSC) analysis. For example, the melting points can be measured by using a differential scanning calorimeter (manufactured by TA Instruments, model DSC Q2000) to raise the temperature to 200° C. at a rate of 5° C./min under a nitrogen gas flow, and determining the peak temperature of the endothermic peak.

The thickness of the base layer 1 is preferably 55 μm or more and 195 μm or less, more preferably 55 μm or more and 190 μm or less, even more preferably 55 μm or more and 170 μm or less, and optimally 60 μm or more and 160 μm or less. By setting the thickness of the base layer 1 within the above range, the dicing tape can be efficiently manufactured, and the semiconductor wafer attached to the dicing tape can be efficiently cut.
The thickness of the base layer 1 can be determined, for example, by measuring the thickness at five randomly selected points using a dial gauge (manufactured by PEACOCK, model R-205) and calculating the arithmetic average of these thicknesses.

In the base layer 1 in which an elastomer layer and a non-elastomer layer are laminated, the ratio of the thickness of the non-elastomer layer to the thickness of the elastomer layer is preferably 1/25 to 1/3, more preferably 1/25 to 1/3.5, even more preferably 1/25 to 1/4, particularly preferably 1/22 to 1/4, and optimally 1/20 to 1/4. By setting the ratio of the thickness of the non-elastomer layer to the thickness of the elastomer layer within the above range, the semiconductor wafer attached to the dicing tape can be more efficiently cleaved.

The elastomer layer may have a single layer (one layer) structure or a laminated structure. The elastomer layer preferably has a one to five layer structure, more preferably a one to three layer structure, even more preferably a one to two layer structure, and optimally a one layer structure. When the elastomer layer has a laminated structure, all layers may contain the same elastomer, or at least two layers may contain different elastomers.

The non-elastomer layer may have a single layer (one layer) structure or a laminated structure. The non-elastomer layer preferably has a one- to five-layer structure, more preferably a one- to three-layer structure, even more preferably a one- to two-layer structure, and optimally a one-layer structure. When the non-elastomer layer has a laminated structure, all layers may contain the same non-elastomer, or at least two layers may contain different non-elastomers.

The non-elastomer layer preferably contains, as a non-elastomer, a polypropylene resin (hereinafter referred to as metallocene PP) which is a polymerization product of a metallocene catalyst. Examples of metallocene PP include propylene/α-olefin copolymers which are polymerization products of a metallocene catalyst. By containing metallocene PP in the non-elastomer layer, the dicing tape can be efficiently produced, and the semiconductor wafer attached to the dicing tape can be efficiently cut.
An example of commercially available metallocene PP is Wintec WFX4M (manufactured by Japan Polypropylene Corporation).

The metallocene catalyst is a catalyst consisting of a transition metal compound of Group 4 of the periodic table (so-called metallocene compound) that contains a ligand having a cyclopentadienyl skeleton, and a cocatalyst that can react with the metallocene compound to activate the metallocene compound to a stable ionic state, and optionally contains an organoaluminum compound. The metallocene compound is a crosslinked metallocene compound that enables stereoregular polymerization of propylene.

Among the propylene/α-olefin copolymers which are polymerization products of the metallocene catalyst, propylene/α-olefin random copolymers which are polymerization products of the metallocene catalyst are preferred, and among the propylene/α-olefin random copolymers which are polymerization products of the metallocene catalyst, those selected from propylene/α-olefin random copolymers having 2 carbon atoms which are polymerization products of the metallocene catalyst, propylene/α-olefin random copolymers having 4 carbon atoms which are polymerization products of the metallocene catalyst, and propylene/α-olefin random copolymers having 5 carbon atoms which are polymerization products of the metallocene catalyst are preferred, and among these, propylene/ethylene random copolymers which are polymerization products of the metallocene catalyst are the most suitable.

The propylene/α-olefin random copolymer, which is a polymerization product of the metallocene catalyst, preferably has a melting point of 80° C. or more and 140° C. or less, particularly 100° C. or more and 130° C. or less, from the viewpoints of coextrusion film-forming property with the elastomer layer and cleavability of a semiconductor wafer attached to a dicing tape.
The melting point of the propylene/α-olefin random copolymer, which is the polymerization product of the metallocene catalyst, can be measured by the method described above.

Here, if the elastomer layer is disposed on the outermost layer of the base layer 1, when the base layer 1 is formed into a roll, the elastomer layers disposed on the outermost layers tend to block (stick together). This makes it difficult to unwind the base layer 1 from the roll. In contrast, in a preferred embodiment of the base layer 1 having the laminated structure described above, a non-elastomer layer/elastomer layer/non-elastomer layer is disposed, i.e., a non-elastomer layer is disposed on the outermost layer, so that the base layer 1 in such an embodiment has excellent blocking resistance. This makes it possible to prevent delays in the manufacture of semiconductor devices using the dicing tape 10 due to blocking.

The non-elastomer layer preferably contains a resin having a melting point of 100° C. or more and 130° C. or less, and a molecular weight dispersity (mass average molecular weight/number average molecular weight) of not more than 5. An example of such a resin is metallocene PP.
By including such a resin in the non-elastomer layer, the non-elastomer layer can be cooled and solidified more quickly in the kerf maintaining step, and therefore, shrinkage of the base layer 1 can be more sufficiently suppressed after the dicing tape is thermally shrunk.
This makes it possible to more sufficiently maintain the kerf in the kerf maintaining step.

The adhesive layer 2 contains an adhesive. The adhesive layer 2 adheres to the semiconductor wafer to be diced into semiconductor chips, thereby holding the semiconductor wafer in place.

The adhesive may be one whose adhesive strength can be reduced by external action during use of the dicing tape 10 (hereinafter referred to as an adhesive reduction type adhesive).

When a reduced-adhesion adhesive is used as the adhesive, during the use of the dicing tape 10, the adhesive layer 2 can be used in either a state where it exhibits a relatively high adhesive strength (hereinafter referred to as a high-adhesion state) or a state where it exhibits a relatively low adhesive strength (hereinafter referred to as a low-adhesion state). For example, when a semiconductor wafer attached to the dicing tape 10 is subjected to cutting, the high-adhesion state is used to prevent the multiple semiconductor chips separated by cutting the semiconductor wafer from lifting up or peeling off from the adhesive layer 2. In contrast, in order to pick up the multiple semiconductor chips separated after cutting the semiconductor wafer, the low-adhesion state is used to make it easier to pick up the multiple semiconductor chips from the adhesive layer 2.

The tack-reducing adhesive may be, for example, an adhesive that can be cured by exposure to radiation during use of the dicing tape 10 (hereinafter referred to as a radiation-curable adhesive).

The radiation-curable adhesive may be, for example, an adhesive that cures when irradiated with electron beams, ultraviolet rays, alpha rays, beta rays, gamma rays, or X-rays. Of these, it is preferable to use an adhesive that cures when irradiated with ultraviolet rays (ultraviolet-curable adhesive).

The radiation-curable adhesive may be, for example, an additive-type radiation-curable adhesive that contains a base polymer such as an acrylic polymer and a radiation-polymerizable monomer component or a radiation-polymerizable oligomer component that has a functional group such as a radiation-polymerizable carbon-carbon double bond.

The acrylic polymer includes a monomer unit derived from a (meth)acrylic acid ester. Examples of the (meth)acrylic acid ester include an alkyl (meth)acrylate ester, a cycloalkyl (meth)acrylate ester, and an aryl (meth)acrylate ester.

The adhesive layer 2 may contain an external crosslinking agent. Any external crosslinking agent can be used as long as it can react with the acrylic polymer, which is the base polymer, to form a crosslinked structure. Examples of such external crosslinking agents include polyisocyanate compounds, epoxy compounds, polyol compounds, aziridine compounds, and melamine-based crosslinking agents.

Examples of the radiation polymerizable monomer component include urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Examples of the radiation polymerizable oligomer component include various oligomers such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based oligomers. The content ratio of the radiation polymerizable monomer component or radiation polymerizable oligomer component in the radiation curable adhesive is selected within a range that appropriately reduces the adhesiveness of the adhesive layer 2.

The radiation-curable adhesive preferably contains a photopolymerization initiator. Examples of photopolymerization initiators include α-ketol compounds, acetophenone compounds, benzoin ether compounds, ketal compounds, aromatic sulfonyl chloride compounds, photoactive oxime compounds, benzophenone compounds, thioxanthone compounds, camphorquinone, halogenated ketones, acylphosphinoxides, and acylphosphonates.

In addition to the above components, the adhesive layer 2 may contain a crosslinking accelerator, a tackifier, an anti-aging agent, a pigment, a colorant such as a dye, etc.

The thickness of the adhesive layer 2 is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 30 μm or less, and even more preferably 5 μm or more and 25 μm or less.

[Dicing die bond film]
Next, the dicing die bond film 20 will be described with reference to Fig. 2. In the description of the dicing die bond film 20, the description of the portions that overlap with the dicing tape 10 will not be repeated.

As shown in Figure 2, the dicing die bond film 20 of this embodiment comprises a dicing tape 10 having an adhesive layer 2 laminated on a base layer 1, and a die bond layer 3 laminated on the adhesive layer 2 of the dicing tape 10.
In the dicing die bond film 20 , a semiconductor wafer is attached onto the die bond layer 3 .
When the semiconductor wafer is cut using the dicing die bond film 20, the die bond layer 3 is also cut together with the semiconductor wafer. The die bond layer 3 is cut into pieces having sizes corresponding to the sizes of the individual semiconductor chips. This makes it possible to obtain semiconductor chips with the die bond layer 3 attached thereto.
As described above, the dicing tape 10 of the dicing die bond film 20 has a tensile storage modulus at -10°C of 50 MPa or more and 250 MPa or less.

The dicing tape 10 of the dicing die bond film 20 preferably has a loss coefficient at -10°C of 0.07 or more and 0.18 or less.
Moreover, the dicing tape 10 of the dicing die bond film 20 preferably has a breaking elongation at -10°C of 450% or more and 600% or less.

It is preferable that the die bond layer 3 has thermosetting properties. By including at least one of a thermosetting resin and a thermoplastic resin having a thermosetting functional group in the die bond layer 3, the die bond layer 3 can be made thermosetting.

When the die bond layer 3 contains a thermosetting resin, examples of such a thermosetting resin include epoxy resin, phenol resin, amino resin, unsaturated polyester resin, polyurethane resin, silicone resin, and thermosetting polyimide resin. Among these, it is preferable to use an epoxy resin.

Epoxy resins include, for example, bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, phenol novolac type, orthocresol novolac type, trishydroxyphenylmethane type, tetraphenylolethane type, hydantoin type, trisglycidyl isocyanurate type, and glycidylamine type epoxy resins.

Examples of phenolic resins that can be used as curing agents for epoxy resins include novolac-type phenolic resins, resol-type phenolic resins, and polyoxystyrenes such as polyparaoxystyrene.

When the die bond layer 3 contains a thermoplastic resin having a thermosetting functional group, for example, a thermosetting functional group-containing acrylic resin can be used as the thermoplastic resin. The acrylic resin in the thermosetting functional group-containing acrylic resin can be one containing a monomer unit derived from a (meth)acrylic acid ester.
In the case of a thermosetting resin having a thermosetting functional group, a curing agent is selected depending on the type of the thermosetting functional group.

The die bond layer 3 may contain a thermosetting catalyst in order to sufficiently advance the curing reaction of the resin component and to increase the curing reaction speed. Examples of thermosetting catalysts include imidazole-based compounds, triphenylphosphine-based compounds, amine-based compounds, and trihalogen borane-based compounds.

The die bond layer 3 may contain a thermoplastic resin. The thermoplastic resin functions as a binder. Examples of the thermoplastic resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as polyamide 6 and polyamide 6,6, phenoxy resin, acrylic resin, saturated polyester resin such as PET and PBT, polyamide-imide resin, fluororesin, etc. Only one type of the above thermoplastic resin may be used, or two or more types may be used in combination. As the above thermoplastic resin, acrylic resin is preferable from the viewpoint that it has a small amount of ionic impurities and has high heat resistance, making it easier to ensure the connection reliability by the die bond layer.

The acrylic resin is preferably a polymer containing a monomer unit derived from a (meth)acrylic acid ester as the monomer unit having the largest mass ratio. Examples of the (meth)acrylic acid ester include an alkyl (meth)acrylic acid ester, a cycloalkyl (meth)acrylic acid ester, and an aryl (meth)acrylic acid ester. The acrylic resin may contain a monomer unit derived from another component that is copolymerizable with the (meth)acrylic acid ester. Examples of the other components include functional group-containing monomers such as carboxyl group-containing monomers, acid anhydride monomers, hydroxyl group-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, acrylamides, and acrylonitriles, and various polyfunctional monomers. From the viewpoint of realizing a high cohesive force in the die bond layer, the acrylic resin is preferably a copolymer of a (meth)acrylic acid ester (particularly a (meth)acrylic acid alkyl ester having an alkyl group with 4 or less carbon atoms), a carboxy group-containing monomer, a nitrogen atom-containing monomer, and a polyfunctional monomer (particularly a polyglycidyl-based polyfunctional monomer), and more preferably a copolymer of ethyl acrylate, butyl acrylate, acrylic acid, acrylonitrile, and polyglycidyl (meth)acrylate.

The die bond layer 3 may contain one or more other components as necessary. Examples of the other components include a flame retardant, a silane coupling agent, and an ion trapping agent.

The thickness of the die bond layer 3 is not particularly limited, but is, for example, 1 μm or more and 200 μm or less. Such a thickness may be 3 μm or more and 150 μm or less, or 5 μm or more and 100 μm or less.

The dicing die bond film 20 according to this embodiment is used, for example, as an auxiliary tool for manufacturing a semiconductor integrated circuit. Specific examples of the use of the dicing die bond film 20 will be described below.
In the following, an example will be described in which a dicing die bond film 20 having a single base layer 1 is used.

The method for manufacturing a semiconductor integrated circuit includes a half-cut process in which a groove is formed in the semiconductor wafer to process the semiconductor wafer into chips (dies) by a fracturing process, a back-grind process in which the semiconductor wafer after the half-cut process is ground to reduce its thickness, a mounting process in which one side of the semiconductor wafer after the back-grind process (for example, the side opposite to the circuit side) is attached to the die-bonding layer 3 and the semiconductor wafer is fixed to the dicing tape 10, an expanding process in which the gap between the half-cut semiconductor chips is widened, a kerf maintaining process in which the gap between the semiconductor chips is maintained, a pick-up process in which the die-bonding layer 3 is peeled off from the adhesive layer 2 to remove the semiconductor chip (die) with the die-bonding layer 3 attached, and a die-bonding process in which the semiconductor chip (die) with the die-bonding layer 3 attached is attached to an adherend. When carrying out these processes, the dicing tape (dicing die-bonding film) of this embodiment is used as a manufacturing aid.

In the half-cut process, as shown in Figures 3A and 3B, a half-cut process is performed to split the semiconductor integrated circuit into small pieces (dies). More specifically, a wafer processing tape T is attached to the surface opposite to the circuit surface of the semiconductor wafer W (see Figure 3A). A dicing ring R is attached to the wafer processing tape T (see Figure 3A). With the wafer processing tape T attached, a groove for division is formed (see Figure 3B). In the back-grind process, as shown in Figures 3C and 3D, the semiconductor wafer is ground to reduce its thickness. More specifically, a back-grind tape G is attached to the surface where the groove is formed, while the wafer processing tape T that was initially attached is peeled off (see Figure 3C). With the back-grind tape G attached, the semiconductor wafer W is ground until it reaches a predetermined thickness (see Figure 3D).

In the mounting process, as shown in Figures 4A and 4B, a dicing ring R is attached to the adhesive layer 2 of the dicing tape 10, and then a half-cut semiconductor wafer W is attached to the exposed surface of the die bond layer 3 (see Figure 4A). Then, the backgrind tape G is peeled off from the semiconductor wafer W (see Figure 4B).

In the expanding step, as shown in Figures 5A to 5C, the dicing ring R is fixed to a holder H of an expanding device. The dicing die bond film 20 is pushed up from below using a push-up member U provided in the expanding device, so that the dicing die bond film 20 is stretched so as to be expanded in the planar direction (see Figure 5B). As a result, the half-cut processed semiconductor wafer W is cleaved under specific temperature conditions. The above temperature conditions are, for example, -20 to 5°C, preferably -15 to 0°C, and more preferably -10 to -5°C. The expanded state is released by lowering the push-up member U (see Figure 5C).
6A to 6B, in the expanding step, the dicing tape 10 is stretched so as to expand its area under a higher temperature condition (for example, room temperature (23° C.)). This causes adjacent cleaved semiconductor chips to be separated in the planar direction of the film surface, further increasing the distance between them.
Here, in the dicing die bond film 20 according to this embodiment, the tensile storage modulus of the dicing tape 10 at -10°C is 50 MPa or more and 250 MPa or less, so that in particular, a semiconductor wafer (e.g., a semiconductor wafer having a diameter of 200 mm (8 inches)) can be sufficiently cleaved by a very small semiconductor chip having an area of 10 ^mm2 or less (e.g., a semiconductor chip having a substantially rectangular surface and a length of 4 mm × width of 2 mm) such as that used in a NAND memory controller.
Furthermore, if the loss coefficient of the dicing tape 10 at -10°C is set to be 0.07 or more and 0.18 or less, not only can the dicing tape 10 be adequately broken into extremely small semiconductor chips as described above, but it is also possible to relatively prevent the dicing tape 10 from breaking when the dicing tape 10 is stretched and broken into extremely small semiconductor chips as described above.
Furthermore, if the breaking elongation of the dicing tape 10 at -10°C is set to 450% or more and 600% or less, not only can the dicing tape 10 be adequately broken into extremely small semiconductor chips as described above, but breaking of the dicing tape 10 can be relatively suppressed when the dicing tape 10 is stretched and broken into extremely small semiconductor chips as described above.

In the kerf maintaining process, as shown in FIG. 7, hot air (e.g., 100 to 130° C.) is applied to the dicing tape 10 to cause the dicing tape 10 to thermally shrink, and then the dicing tape 10 is cooled and solidified, thereby maintaining the distance (kerf) between adjacent cleaved semiconductor chips.
Here, in the dicing die bond film 20 according to this embodiment, the tensile storage modulus of the dicing tape 10 at −10° C. is 50 MPa or more and 250 MPa or less, so that the kerf can be adequately maintained after being cleaved into extremely small semiconductor chips.

In the pick-up process, as shown in FIG. 8, the semiconductor chip with the die bond layer 3 attached is peeled off from the adhesive layer 2 of the dicing tape 10. More specifically, the pin member P is raised to push up the semiconductor chip to be picked up through the dicing tape 10. The pushed-up semiconductor chip is held by the suction jig J.

In the die bonding step, the semiconductor chip with the die bonding layer 3 attached thereto is bonded to an adherend.
In the above-mentioned manufacturing method of the semiconductor integrated circuit, an example in which the dicing die bond film 20 is used as an auxiliary tool has been described, but the semiconductor integrated circuit can also be manufactured in the same manner as described above when the dicing tape 10 is used as an auxiliary tool.

The dicing tape and dicing die bond film of the present invention are not limited to the above-mentioned embodiment. The dicing tape and dicing die bond film of the present invention are also not limited by the above-mentioned action and effect. The dicing tape and dicing die bond film of the present invention can be modified in various ways without departing from the gist of the present invention.

Next, the present invention will be described in more detail with reference to examples. The following examples are intended to explain the present invention in more detail and are not intended to limit the scope of the present invention.

[Example 1]
<Forming of Base Layer>
A two-kind three-layer extrusion T-die molding machine was used to mold a substrate layer having a three-layer structure of A layer/B layer/C layer (a three-layer structure in which B layer is the central layer and A layer and C layer are laminated on both sides of B layer as outer layers). Metallocene PP (product name: Wintech WFX4M, manufactured by Japan Polypropylene Corporation) was used as the resin for A layer and C layer, and EVA (product name: Evaflex EV250, manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) was used as the resin for B layer.
The extrusion was performed at a die temperature of 190° C. That is, the A layer, the B layer, and the C layer were extruded at 190° C. The thickness of the base layer obtained by extrusion was 100 μm. The thickness ratio (layer thickness ratio) of the A layer, the B layer, and the C layer was A layer:B layer:C layer=1:10:1.
After the molded base layer was sufficiently solidified, the solidified base layer was wound into a roll to form a roll body.
<Preparation of dicing tape>
The adhesive composition was applied to one surface of the rolled substrate layer using an applicator to a thickness of 10 μm. The substrate layer after application of the adhesive composition was heated and dried at 110° C. for 3 minutes to form an adhesive layer, thereby obtaining a dicing tape.
The pressure-sensitive adhesive composition was prepared as follows.
First, 173 parts by mass of INA (isononyl acrylate), 54.5 parts by mass of HEA (hydroxyethyl acrylate), 0.46 parts by mass of AIBN (2,2'-azobisisobutyronitrile), and 372 parts by mass of ethyl acetate were mixed to obtain a first resin composition.
Next, the first resin composition was added into a round-bottom separable flask of a polymerization experimental apparatus equipped with a round-bottom separable flask (volume 1 L), a thermometer, a nitrogen inlet tube, and a stirring blade, and while stirring the first resin composition, the liquid temperature of the first resin composition was brought to room temperature (23°C), and the inside of the round-bottom separable flask was replaced with nitrogen for 6 hours.
While continuing to flow nitrogen into the round-bottom separable flask, the first resin composition was stirred while the liquid temperature of the first resin composition was maintained at 62° C. for 3 hours and then at 75° C. for 2 hours to polymerize the INA, the HEA, and the AIBN to obtain a second resin composition. Then, the flow of nitrogen into the round-bottom separable flask was stopped.
The second resin composition was cooled until the liquid temperature reached room temperature, and then 52.5 parts by mass of 2-isocyanatoethyl methacrylate (manufactured by Showa Denko K.K., product name "Karenz MOI (registered trademark)") and 0.26 parts by mass of dibutyltin dilaurate IV (manufactured by Wako Pure Chemical Industries, Ltd.) were added to the second resin composition as a compound having a polymerizable carbon-carbon double bond, and the resulting third resin composition was stirred in an air atmosphere at a liquid temperature of 50°C for 24 hours.
Next, 0.75 parts by mass of Coronate L (isocyanate compound) and 2 parts by mass of Omnirad 127 (photopolymerization initiator) were added to the third resin composition per 100 parts by mass of polymer solids, and then the third resin composition was diluted with ethyl acetate to a solids concentration of 20% by mass to prepare a pressure-sensitive adhesive composition.
<Preparation of dicing die bond film>
100 parts by mass of an acrylic resin (manufactured by Nagase ChemteX Corporation, product name "SG-P3", glass transition temperature 12°C), 46 parts by mass of an epoxy resin (manufactured by Mitsubishi Chemical Corporation, product name "JER1001"), 51 parts by mass of a phenolic resin (manufactured by Meiwa Kasei Co., Ltd., product name "MEH-7851ss"), 191 parts by mass of spherical silica (manufactured by Admatechs Co., Ltd., product name "SO-25R"), and 0.6 parts by mass of a curing catalyst (manufactured by Shikoku Kasei Corporation, product name "Curesol PHZ") were added to methyl ethyl ketone and mixed to obtain a die bond composition with a solid content concentration of 20% by mass.
Next, the die bond composition was applied to a silicone-treated surface of a PET-based separator (thickness 50 μm) serving as a release liner using an applicator to a thickness of 10 μm, and the die bond composition was dried at 130° C. for 2 minutes to remove the solvent, thereby obtaining a die bond sheet in which a die bond layer was laminated on the release liner.
Next, the side of the die bond sheet on which the release sheet was not laminated was attached to the adhesive layer of the dicing tape, and then the release liner was peeled off from the die bond layer to obtain a dicing die bond film having a die bond layer.

For the dicing tape obtained as above, the tensile storage modulus at -10°C and the loss modulus at -10°C were measured as follows, and the loss factor at -10°C was calculated.
The breaking elongation at -10°C was calculated by measuring the length of the test piece at break as follows.
Furthermore, the ability to break into very small chips using the dicing die bond film during expansion and the ability to maintain the kerf were evaluated.

(Tensile storage modulus and loss factor)
A test piece having a length of 40 mm (measurement length) × width of 10 mm was cut out from the dicing tape of Example 1, and the tensile storage modulus and loss modulus of the test piece were measured in the temperature range of −50 to 100° C. using a solid viscoelasticity measuring device (model RSAIII, manufactured by Rheometric Scientific Co., Ltd.) under conditions of a frequency of 1 Hz, a strain amount of 0.1%, a heating rate of 10° C./min, and a chuck distance of 22.5 mm.
At that time, the value at -10°C was read to determine the tensile storage modulus at -10°C and the loss modulus at -10°C.
Moreover, the loss factor at -10°C was calculated by dividing the tensile storage modulus at -10°C by the loss factor at -10°C.

(Elongation at break)
A test piece having a length of 120 mm (measurement length, L ₀ ) x width of 10 mm was cut out from the dicing tape of Example 1, and the test piece was pulled in the longitudinal direction using a tensile testing machine (Autograph AG-IS, manufactured by Shimadzu Corporation) under conditions of a measurement temperature of -10°C, a chuck distance of 50 mm, and a tensile speed of 100 mm/min, and the length (L ₁ ) at which the test piece broke was measured.
Then, the breaking elongation E at −10° C. was calculated based on the following formula.

Breaking elongation E=(L ₁ −L ₀ )/L ₀ ×100

(Ability to break into extremely small chips)
A bare wafer (diameter 300 mm) and a dicing ring were attached to the dicing die bond film according to Example 1. Next, the semiconductor wafer and the die bond layer were cut using a die separator DDS2300 (manufactured by Disco Corporation), and the cuttability into ultra-small chips was evaluated. The bare wafer was cut into bare chips (ultra-small chips) with a size of 2 mm long x 2 mm wide x 0.030 mm thick.

The breakability was evaluated in detail as follows.
First, the bare wafer and the die bond layer were cleaved in a cool expander unit under the conditions of an expansion temperature of −15° C., an expansion speed of 100 mm/sec, and an expansion amount of 14 mm to obtain a semiconductor chip with a die bond layer.
Next, expansion was performed under the conditions of room temperature, expansion speed of 1 mm/sec, and expansion amount of 8 mm. Then, while maintaining the expanded state, the dicing die bond film at the boundary with the outer periphery of the bare wafer was thermally shrunk under the conditions of a heat temperature of 250° C., a heat distance of 18 mm, and a rotation speed of 5°/sec.
Next, the fractured portion of the semiconductor chip with the die bond layer was observed by a microscope, and the fracture rate was calculated. Then, a fracture rate of 90% or more was evaluated as ◯, and a fracture rate of less than 90% was evaluated as ×.

(Evaluation of kerf retention)
A bare wafer (diameter 300 mm, hereinafter also referred to as a circular wafer) and a dicing ring were attached to the dicing die bond film according to Example 1. Next, the bare wafer and the die bond layer were cut using a die separator DDS2300 (manufactured by Disco Corporation), and the kerf retention after cutting was evaluated.
The bare wafer was cleaved into bare chips (very small chips) measuring 2 mm in length x 2 mm in width x 0.030 mm in thickness.

The kerf retention was evaluated in detail as follows.
First, the bare wafer and the die bond layer were cleaved in a cool expander unit under conditions of an expansion temperature of −15° C., an expansion speed of 100 mm/sec, and an expansion amount of 14 mm to obtain a plurality of bare chips with a die bond layer.
Next, room temperature expansion was performed under the conditions of room temperature, expansion speed of 1 mm/sec, and expansion amount of 5 mm. Then, while maintaining the expanded state, the dicing die bond film at the boundary with the outer periphery of the bare wafer was thermally shrunk under the conditions of heat temperature of 250° C., heat distance of 18 mm, and rotation speed of 5°/sec.
Next, the kerf was measured using a digital microscope (VHX-6000, manufactured by Keyence Corporation). More specifically, after the heat expansion was completed (after the heat shrinkage), the interval between one chip and another chip in the cleaved portion (hereinafter also referred to as the interval length) was observed with a digital microscope to measure the interval length. The interval length was measured in each of the MD and TD directions at five arbitrarily selected points. The minimum value of the interval length measurements was used as the kerf.
If the kerf was 30 μm or more, it was evaluated as ◯ (the kerf was maintained), and if the kerf was less than 30 μm, it was evaluated as × (the kerf was not maintained).
The five arbitrarily selected locations are four locations on the outermost periphery of the circular wafer that are spaced apart from each other by approximately 90° in the circumferential direction, and the vicinity of the center of the circular wafer.

[Example 2]
The dicing tape and dicing die bond film of Example 2 were obtained in the same manner as in Example 1, except that a first polymer blend (a blend of Evaflex EV250 and HDPE (high density polyethylene). The mass ratio was EV250:HDPE=90:10. Manufactured by DuPont-Mitsui Polychemicals) was used for the B layer of the base material layer.
In addition, for the dicing tape of Example 2, the tensile storage modulus at -10°C and the loss modulus at -10°C were measured in the same manner as in Example 1, and the breaking elongation at -10°C and the loss factor at -10°C were calculated.
Furthermore, in the same manner as in Example 1, the ability to break into very small chips using the dicing die bond film during expansion and the ability to maintain the kerf were evaluated.

[Example 3]
The dicing tape and dicing die bond film of Example 3 were obtained in the same manner as in Example 1, except that the base layer had a single layer structure and Evaflex P1007 (manufactured by Mitsui DuPont Polychemicals) was used as the resin constituting the resin layer.
In addition, for the dicing tape of Example 3, the tensile storage modulus at -10°C and the loss modulus at -10°C were measured in the same manner as in Example 1, and the breaking elongation at -10°C and the loss factor at -10°C were calculated.
Furthermore, in the same manner as in Example 1, the ability to break into very small chips using the dicing die bond film during expansion and the ability to maintain the kerf were evaluated.

[Comparative Example 1]
A dicing tape and a dicing die bond film according to Comparative Example 1 were obtained in the same manner as in Example 1, except that a second polymer blend (a blend of Evaflex EV250 and HDPE (high density polyethylene). Mass ratio: EV250:HDPE = 80:20. Manufactured by DuPont-Mitsui Polychemicals) was used for the B layer of the base material layer.
Moreover, for the dicing tape of Comparative Example 1, the tensile storage modulus at -10°C and the loss modulus at -10°C were measured in the same manner as in Example 1, and the breaking elongation at -10°C and the loss factor at -10°C were calculated.
Furthermore, in the same manner as in Example 1, the ability to break into very small chips using the dicing die bond film during expansion and the ability to maintain the kerf were evaluated.

[Comparative Example 2]
A dicing tape and a dicing die bond film according to Comparative Example 2 were obtained in the same manner as in Example 1, except that Evaflex V523 (manufactured by DuPont-Mitsui Polychemicals) was used for the B layer of the base material layer.
In addition, for the dicing tape of Comparative Example 2, the tensile storage modulus at -10°C and the loss modulus at -10°C were measured in the same manner as in Example 1, and the breaking elongation at -10°C and the loss factor at -10°C were calculated.
Furthermore, in the same manner as in Example 1, the ability to break into very small chips using the dicing die bond film during expansion and the ability to maintain the kerf were evaluated.

The results of measuring the tensile storage modulus at -10°C and the loss modulus at -10°C for the dicing tape of each example, as well as the results of calculating the breaking elongation at -10°C and the loss factor at -10°C, are shown in Table 1 below. The results of evaluating the ability of the dicing die bond film of each example to break into extremely small chips and maintain the kerf are also shown.

From Table 1, it can be seen that the dicing tapes of Examples 1 to 3 all have a tensile storage modulus at -10°C in the range of 50 MPa or more and 250 MPa or less, and that the dicing die bond films of Examples 1 to 3 are excellent in terms of their ability to be broken into extremely small chips and their ability to maintain kerf.
Furthermore, as can be seen from Table 1, the dicing tapes according to Examples 1 to 3 all had loss coefficient values at -10°C in the range of 0.07 or more and 0.18 or less, and breaking elongation values at -10°C in the range of 450% or more and 600% or less.
In contrast, the dicing tapes of Comparative Examples 1 and 2 both had tensile storage modulus values outside the range of 50 MPa or more and 250 MPa or less at -10°C, and it can be seen that the dicing die bond films of Comparative Examples 1 and 2 were inferior in terms of their ability to be broken into extremely small chips and their ability to maintain kerf.
Furthermore, from Table 1, the dicing tapes according to Comparative Examples 1 and 2 both had loss coefficient values outside the range of 0.07 or more and 0.18 or less at -10°C, and had breaking elongation values outside the range of 450% or more and 600% or less at -10°C. In particular, when the dicing die bond film according to Comparative Example 1 was used to evaluate the ability to break into extremely small chips and the kerf retention, damage (tears) that would be problematic in practical use were observed in the dicing tape.
Note that the evaluation of the ability to break extremely small chips and the evaluation of the ability to maintain the kerf shown in Table 1 are for the dicing die bond film, but it is expected that results similar to those shown in Table 1 will be obtained for the dicing tape contained in the dicing die bond film.

REFERENCE SIGNS LIST 1 Base layer 2 Pressure sensitive adhesive layer 3 Die bond layer 10 Dicing tape 20 Dicing die bond film 1a First resin layer 1b Second resin layer 1c Third resin layer G Back grinding tape H Holder J Suction jig T Wafer processing tape U Push-up member W Semiconductor wafer

Claims (4)

A dicing tape having a pressure-sensitive adhesive layer laminated on a base layer,
The tensile storage modulus at −10° C. is 50 MPa or more and 250 MPa or less,
The breaking elongation at -10°C is 450% or more and 600% or less.
Dicing tape. The loss coefficient at -10°C is 0.07 or more and 0.18 or less.
The dicing tape according to claim 1 . The base layer contains polyethylene, polypropylene, poly1-butene, poly(4-methyl-1-pentene), ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/propylene/1-butene copolymer, propylene/1-butene copolymer, ethylene-vinyl acetate copolymer, or α-olefin-based thermoplastic elastomer.
The dicing tape according to claim 1 or 2. a dicing tape having a pressure-sensitive adhesive layer laminated on a base layer;
A die bond layer laminated on the pressure-sensitive adhesive layer of the dicing tape,
The dicing tape has a tensile storage modulus of 50 MPa or more and 250 MPa or less at −10° C., and a breaking elongation of 450% or more and 600% or less at −10° C.;
Dicing die bond film.