JP7539769B2 - Die bond sheet and dicing die bond film - Google Patents

Description

The present invention relates to a die bond sheet and a dicing die bond film equipped with the die bond sheet, which are used, for example, when manufacturing semiconductor integrated circuits.

Conventionally, dicing die bond films used in the manufacture of semiconductor integrated circuits are known. This type of dicing die bond film comprises, for example, a dicing tape and a die bond sheet that is laminated to the dicing tape and adhered to a wafer. The dicing tape has a base layer and an adhesive layer that is in contact with the die bond sheet. This type of dicing die bond film is used in the manufacture of semiconductor integrated circuits, for example, as follows.

The method of manufacturing semiconductor integrated circuits generally involves a front-end process in which a circuit surface is formed on one side of a wafer using highly integrated electronic circuits, and a back-end process in which chips are cut out from the wafer with the circuit surface formed and assembled.

The post-processing includes, for example, a dicing process in which grooves are formed in the wafer to split it into small chips (dies); a mounting process in which the surface of the wafer opposite the circuit surface is attached to a die bond sheet and the wafer is fixed to the dicing tape; an expanding process in which the wafer with the grooves formed is split together with the die bond sheet to widen the gap between the chips; a pick-up process in which the die bond sheet is peeled off from the adhesive layer to remove the chip (die) with the die bond sheet attached; and a die bond process in which the chip (die) with the die bond sheet attached is attached to an adherend. Semiconductor integrated circuits are manufactured through these processes.

In the manufacturing method of semiconductor integrated circuits as described above, a die bond sheet is known that contains a specific content of thermoplastic resin components and thermosetting resin components and has a surface free energy within a specific range in order to improve performance in the pick-up process and die bond process (for example, Patent Document 1).

Specifically, in the die bond sheet described in Patent Document 1, the thermoplastic resin component accounts for 15 to 30 mass % of the organic resin components contained therein, and the thermosetting resin component accounts for 60 to 70 weight %. Also, the surface free energy is 37 mJ/ ^m2 or more and less than 40 mJ/ ^m2 .
The die-bonding sheet described in Patent Document 1 can exhibit good peelability from the pressure-sensitive adhesive layer in a pick-up step, and can also exhibit good adhesion to an adherend in a die-bonding step.

Incidentally, with the recent progress in integration technology, for example, in the above-mentioned die bonding process, relatively thin chips (dies) with die bond sheets attached thereto may be stacked multiple times.
However, when chips (dies) with die bond sheets attached as described in Patent Document 1 are stacked, a so-called floating may occur due to poor adhesion between the die bond sheet and the chip (die).
In order to prevent such problems, there is a demand for a die bond sheet that can suppress floating when chips (dies) are stacked.

JP 2008-244463 A

However, it cannot be said that sufficient research has been conducted yet on die bond sheets that can suppress floating when chips (dies) are stacked, and on dicing die bond films that include such die bond sheets.

The present invention aims to provide a die bond sheet and a dicing die bond film that can prevent chips (dies) from floating when stacked.

In order to solve the above problems, the die bond sheet according to the present invention is characterized in that the peel strength from a polyimide resin surface is 0.1 N/50 mm or more.
According to the die bond sheet having the above configuration, floating of chips (dies) when stacked can be suppressed.

In the above die bond sheet, it is preferable that the surface free energy is 35 mJ/ ^m2 or less, and the proportion of the dispersion component in the surface free energy is 95% or more. This makes it possible to more sufficiently suppress floating when chips (dies) are stacked.

The above die bond sheet preferably has a contact angle with water of 90° or more and a contact angle with methylene iodide of 50° or more. This makes it possible to more sufficiently suppress floating when chips (dies) are stacked.

The dicing die bond film of the present invention comprises the above-mentioned die bond sheet and a dicing tape attached to the die bond sheet.

The die bond sheet and dicing die bond film of the present invention have the effect of suppressing floating when chips (dies) are stacked.

FIG. 2 is a cross-sectional view of the dicing die bond film of the present embodiment cut in the thickness direction. 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 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 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 illustrating a pickup step in a method for manufacturing a semiconductor integrated circuit. FIG. 1 is a cross-sectional view that illustrates a schematic view of how chips (dies) are stacked.

Below, we will explain the die bond sheet of the present invention and an embodiment of a dicing die bond film equipped with the die bond sheet with reference to the drawings.

As shown in FIG. 1, the dicing die bond film 1 of this embodiment comprises a dicing tape 20 and a die bond sheet 10 that is laminated to the adhesive layer 22 of the dicing tape 20 and adhered to a semiconductor wafer. The die bond sheet 10 is adhered to an adherend such as a circuit board or a semiconductor chip in the manufacture of a semiconductor integrated circuit.

<Dicing die bond film die bond sheet>
The die bond sheet 10 has a peel strength against the polyimide resin surface of 0.1 N/50 mm or more. If the peel strength is less than 0.1 N/50 mm, there is a risk that floating when stacking chips (dies) cannot be suppressed. In addition, when the die bond sheet 10 is cured by heating or the like, the peel strength is the value before the curing treatment. In addition, the peel strength is the peel strength of the surface of the die bond sheet 10 that is bonded to the adhesive layer 22 (described in detail later) (the surface that is bonded to the adherend).
The peel force is measured by the method described in the Examples.
The polyimide resin surface used for measuring the peel strength of the die bond sheet 10 is the surface of a specific polyimide resin film.
The physical properties of the polyimide resin film used for measurement are as follows: A polyimide resin film having the following physical properties is used in the measurement of peel strength.
Static friction coefficient: 0.48 (JIS K 7125)
Dynamic friction coefficient: 0.42 (JIS K 7125)
Surface roughness [Ra]: 0.03 to 0.07 μm (JIS B 0601)
Density [g cm ⁻³ ]: 1.42 (Archimedes method)
In principle, a product named "Kapton 100H" manufactured by Toray DuPont Co., Ltd., which is commercially available at the time of filing this application, is used as the polyimide resin film for measurement.

The surface free energy of the polyimide resin surface used in the above-mentioned peel force measurement is usually 25 mJ/ ^m2 or more and 35 mJ/ ^m2 or less, and the proportion of the dispersion component in the surface free energy is 85% or more and 95% or less.

The peeling force may be 0.2 N/50 mm or more. When the peeling force is 0.2 N/50 mm or more, floating of chips (dies) when stacked can be more sufficiently suppressed.
The peel force may be 0.5 N/50 mm or less.

For example, the peeling force can be increased by increasing the content of thermoplastic resin or thermosetting resin and decreasing the content of inorganic filler. On the other hand, the peeling force can be decreased by decreasing the content of thermoplastic resin or thermosetting resin and increasing the content of inorganic filler.

In the die bond sheet 10, it is preferable that the surface free energy is 35 mJ/m ² or less, and the proportion of the dispersion component in the surface free energy is 95% or more.
The surface free energy is 35 mJ/ ^m2 or less and the proportion of the dispersed components is 95% or more, which has the advantage that floating of chips (dies) when stacked can be more sufficiently suppressed.
The above surface free energy may be 25 mJ/ ^m2 or more, or may be 30 mJ/ ^m2 or more.

The method for measuring the above surface free energy will now be described in detail.
The above surface free energy is calculated from the results of contact angle measurement performed as follows: In detail, the contact angles of droplets of water (H ₂ O) and methylene iodide (CH ₂ I ₂ ) contacting the surface of the die bond sheet 10 are measured using a contact angle meter under conditions of 20° C. and 65% relative humidity.
Next, the surface free energy is calculated from the measured values of the contact angle θw of water and the contact angle θi of methylene iodide as follows: In detail, γs ^d (dispersion component of surface free energy) and ^γsh (polar component of surface free energy) are calculated according to the method of Owens et al. described in Journal of Applied Polymer Science, vol. 13, pp. 1741-1747 (1969).
Then, the value γs (=γs ^d + ^γsh ) obtained by adding γs ^d and ^γsh is defined as the surface free energy of the die bond sheet 10 .
The values of γs ^d (dispersion component) and ^γsh (polar component) are obtained as solutions to simultaneous equations with two unknowns, the following formulas (1) and (2). In formulas (1) and (2), γw is the surface free energy of water, ^γwd is the dispersion component of the surface free energy of water, ^γwh is the polar component of the surface free energy of water, γi is the surface free energy of methyl iodide, ^γid is the dispersion component of the surface free energy of methyl iodide, and ^γih is the polar component of the surface free energy of methyl iodide, and are known values as shown below.
γw=72.8 [mJ/m ² ]
γw ^d =21.8 [mJ/m ² ]
γw ^h =51.0 [mJ/m ² ]
γi=50.8 [mJ/m ² ]
^γid = 48.5 [mJ/m ² ]
γi ^h =2.3 [mJ/m ² ]

It is preferable that the surface of the die bond sheet 10 has a contact angle with water of 90° or more and a contact angle with methylene iodide of 50° or more.
This has the advantage that floating of chips (dies) when stacked can be more sufficiently suppressed.

The surface of the die bond sheet 10 preferably has a contact angle with water of 95° or more. This has the advantage that floating of chips (dies) when stacked can be more sufficiently suppressed.
The surface of the die bond sheet 10 may have a contact angle with water of 110° or less.

The surface of the die bond sheet 10 preferably has a contact angle with methylene iodide of 52° or more. This has the advantage that floating of chips (dies) when stacked can be more sufficiently suppressed.
The surface of the die bond sheet 10 may have a contact angle with methylene iodide of 60° or less.

In this specification, the surface free energy is divided into a dispersion component and a polar component as described above. In general, the dispersion component of the surface free energy is a physical quantity that reflects the density, molecular weight, hardness, etc. of a substance. For example, in the surface free energy of oxides or metals, the dispersion component is low, while in the case of organic materials, the dispersion component is high. In contrast, the polar component is a physical quantity that reflects the density or activity of polar groups on the surface. The dispersion component on a solid surface does not become "zero", but the polar component can become "zero". When each component is considered in terms of the intermolecular interaction between surfaces, the dispersion component is expressed as the Coulomb attraction between two nonpolar molecules (dipoles) and is called the London dispersion energy. On the other hand, the polar component is called the permanent dipole-dipole (Keesom) energy and the permanent dipole-nonpolar dipole (Debye) energy.

It is more preferable that the proportion of the dispersive components in the surface free energy of the die bond sheet 10 is 97% or more. By increasing the proportion of the dispersive components, there is an advantage that the wettability and spreadability of the die bond sheet 10 to a general adherend is increased. The proportion of the dispersive components may be 100% or less.
The dispersion component may be 25 mJ/ ^m2 or more and 35 mJ/ ^m2 or less.

In order to reduce the above-mentioned surface free energy and to increase the contact angle with water or methylene iodide, for example, a raw material with a lower polarity is selected as the raw material (such as resin) to be mixed into the die bond sheet 10, or the mixing ratio of the raw material with a lower polarity is increased. On the other hand, in order to increase the above-mentioned surface free energy and to reduce the contact angle with water or methylene iodide, for example, a raw material with a higher polarity is selected as the raw material (such as resin) to be mixed into the die bond sheet 10, or the mixing ratio of the raw material with a higher polarity is increased.

The die bond sheet 10 may contain at least one of a thermosetting resin and a thermoplastic resin. It is preferable that the die bond sheet 10 contains a thermosetting resin and a thermoplastic resin.

Examples of thermosetting resins include epoxy resins, phenolic resins, amino resins, unsaturated polyester resins, polyurethane resins, silicone resins, and thermosetting polyimide resins. As the thermosetting resin, only one type or two or more types are used. As the thermosetting resin, epoxy resins are preferred because they contain less ionic impurities that may cause corrosion of the semiconductor chip to be die-bonded. As a curing agent for epoxy resins, phenolic resins are preferred.

Examples of the epoxy resins include 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.

Phenol resins can act as curing agents for epoxy resins. Examples of phenol resins include novolac-type phenol resins, resol-type phenol 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.
As the phenolic resin, one kind or two or more kinds may be adopted.

In the die bond sheet 10, the hydroxyl groups of the phenolic resin are preferably 0.5 equivalents or more and 2.0 equivalents or less, more preferably 0.7 equivalents or more and 1.5 equivalents or less, per equivalent of the epoxy groups of the epoxy resin. This allows the curing reaction between the epoxy resin and the phenolic resin to proceed sufficiently.

When the die bond sheet 10 contains a thermosetting resin, the content of the thermosetting resin in the die bond sheet 10 is preferably 5% by mass or more and 60% by mass or less, and more preferably 10% by mass or more and 50% by mass or less, relative to the total mass of the die bond sheet 10. This allows the die bond sheet 10 to properly exhibit its function as a thermosetting adhesive.

Examples of thermoplastic resins that can be included in the die bond sheet 10 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 resins such as 6-polyamide resin and 6,6-polyamide resin, phenoxy resin, acrylic resin, saturated polyester resins such as PET and PBT, polyamideimide resin, and fluororesin.
As the thermoplastic resin, an acrylic resin is preferable in that it has a small amount of ionic impurities and high heat resistance, and therefore the adhesiveness of the die bond sheet 10 can be further ensured.
As the thermoplastic resin, one kind or two or more kinds may be adopted.

The acrylic resin is preferably a polymer in which the constituent units in the molecule are primarily alkyl (meth)acrylates, such as C2 to C4 alkyl (meth)acrylates.
The acrylic resin may contain a structural unit derived from another monomer component copolymerizable with the alkyl (meth)acrylate monomer.
Examples of the other monomer components include carboxy group-containing monomers, acid anhydride monomers, hydroxy group (hydroxyl group)-containing monomers, glycidyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, functional group-containing monomers such as acrylamide and acrylonitrile, and various other polyfunctional monomers.
The acrylic resin is preferably a copolymer of an alkyl(meth)acrylate (particularly an alkyl(meth)acrylate having an alkyl portion 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), in that it can exert a higher cohesive force in the die bond sheet 10, and more preferably a copolymer of ethyl acrylate, butyl acrylate, acrylic acid, acrylonitrile, and polyglycidyl(meth)acrylate.
The acrylic resin is preferably an acrylic resin having an acrylonitrile content of 10 mass % or less, which has the advantage that the proportion of polar components in the surface free energy of the die bond sheet 10 can be further reduced.

The glass transition temperature (Tg) of the acrylic resin is preferably -50°C or higher and 50°C or lower, and more preferably 10°C or higher and 30°C or lower, in order to easily set the elasticity and viscosity of the die bond sheet 10 within the desired range.

When the die bond sheet 10 contains a thermosetting resin and a thermoplastic resin, the content of the thermoplastic resin in the die bond sheet 10 is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, based on the total mass of organic components excluding the filler (e.g., thermosetting resin, thermoplastic resin, curing catalyst, silane coupling agent, dye). By changing the content of the thermosetting resin, the elasticity and viscosity of the die bond sheet 10 can be adjusted.

When the thermoplastic resin of the die bond sheet 10 has a thermosetting functional group, for example, a thermosetting functional group-containing acrylic resin can be used as the thermoplastic resin. This thermosetting functional group-containing acrylic resin preferably contains a structural unit derived from an alkyl (meth)acrylate in the molecule in the largest mass ratio. Examples of the alkyl (meth)acrylate include the (meth)alkyl (meth)acrylate exemplified above.
On the other hand, examples of the thermosetting functional group in the thermosetting functional group-containing acrylic resin include a glycidyl group, a carboxy group, a hydroxyl group, and an isocyanate group.
The die bond sheet 10 preferably contains a thermosetting functional group-containing acrylic resin and a curing agent. Examples of the curing agent include those exemplified as curing agents that can be contained in the adhesive layer 22. When the thermosetting functional group in the thermosetting functional group-containing acrylic resin is a glycidyl group, it is preferable to use a compound having a plurality of phenol structures as the curing agent. For example, the above-mentioned various phenol resins can be used as the curing agent.

The die bond sheet 10 preferably contains a filler. By changing the amount of the filler in the die bond sheet 10, it is possible to more easily adjust the elasticity and viscosity of the die bond sheet 10. Furthermore, it is possible to adjust the physical properties of the die bond sheet 10, such as electrical conductivity, thermal conductivity, and elastic modulus.
The filler may be an inorganic filler or an organic filler, and the inorganic filler is preferred.
Examples of inorganic fillers include fillers containing aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, boron nitride, silica such as crystalline silica and amorphous silica, etc. Examples of the material of the inorganic filler include simple metals such as aluminum, gold, silver, copper, nickel, etc., and alloys, etc. Fillers such as aluminum borate whiskers, amorphous carbon black, graphite, etc. The shape of the filler may be various shapes such as spherical, needle-like, flake-like, etc. As the filler, only one of the above types or two or more types are used.

The average particle size of the filler is preferably 0.005 μm or more and 10 μm or less, and more preferably 0.005 μm or more and 1 μm or less. When the average particle size is 0.005 μm or more, the wettability and adhesion to the adherend such as a semiconductor wafer are further improved. When the average particle size is 10 μm or less, the characteristics of the added filler can be more fully exhibited, and the heat resistance of the die bond sheet 10 can be further exhibited. The average particle size of the filler can be determined, for example, using a photometric particle size distribution meter (for example, product name "LA-910", manufactured by Horiba, Ltd.).

When the die bond sheet 10 contains a filler, the content of the filler is preferably 30% by mass or more and 70% by mass or less, more preferably 40% by mass or more and 60% by mass or less, and even more preferably 42% by mass or more and 55% by mass or less, relative to the total mass of the die bond sheet 10.

The die bond sheet 10 may contain other components as necessary. Examples of the other components include a curing catalyst, a flame retardant, a silane coupling agent, an ion trapping agent, and a dye.
Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resins.
Examples of the silane coupling agent include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyldiethoxysilane.
Examples of the ion trapping agent include hydrotalcites, bismuth hydroxide, and benzotriazole.
As the other additives, one kind may be used alone, or two or more kinds may be used in combination.

The die bond sheet 10 preferably contains a thermoplastic resin (particularly, an acrylic resin), a thermosetting resin, and a filler, in that the elasticity and viscosity can be easily adjusted.
In the die bond sheet 10, the content ratio of thermoplastic resin such as acrylic resin to the total mass of organic components excluding the filler is preferably 30 mass% or more and 70 mass% or less, more preferably 40 mass% or more and 60 mass% or less, and even more preferably 45 mass% or more and 55 mass% or less.
The filler content relative to the total mass of the die bond sheet 10 is preferably 30 mass% or more and 70 mass% or less, more preferably 40 mass% or more and 60 mass% or less, and even more preferably 42 mass% or more and 55 mass% or less.

The thickness of the die bond sheet 10 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. Note that, when the die bond sheet 10 is a laminate, the above thickness is the total thickness of the laminate.

The die bond sheet 10 may have a single-layer structure, for example, as shown in Fig. 1. In this specification, a single layer means having only a layer formed of the same composition. A form in which a plurality of layers formed of the same composition are laminated is also a single layer.
On the other hand, the die bond sheet 10 may have a multi-layer structure in which layers each formed of, for example, two or more different compositions are laminated.

In the dicing die bond film 1 of this embodiment, when used, the adhesive layer 22 is cured by irradiation with active energy rays (e.g., ultraviolet rays). In detail, in a state in which the die bond sheet 10 having a semiconductor wafer adhered to one side and the adhesive layer 22 bonded to the other side of the die bond sheet 10 are laminated, ultraviolet rays or the like are irradiated to at least the adhesive layer 22. For example, ultraviolet rays or the like are irradiated from the side where the base layer 21 is arranged, and the ultraviolet rays or the like reach the adhesive layer 22 after passing through the base layer 21. The adhesive layer 22 is cured by irradiation with ultraviolet rays or the like.
Since the adhesive layer 22 hardens after irradiation, the adhesive strength of the adhesive layer 22 can be reduced, so that the die bond sheet 10 (with the semiconductor wafer adhered thereto) can be relatively easily peeled off from the adhesive layer 22 after irradiation.

The dicing die bond film 1 of the present embodiment may be provided with a release sheet that covers one surface of the die bond sheet 10 (the surface where the die bond sheet 10 does not overlap with the pressure-sensitive adhesive layer 22) before use. The release sheet is used to protect the die bond sheet 10, and is peeled off immediately before attaching an adherend (e.g., a semiconductor wafer) to the die bond sheet 10.
As this release sheet, the same release sheet as described above can be used. This release sheet can be used as a support material for supporting the die bond sheet 10. The release sheet is preferably used when the die bond sheet 10 is overlaid on the adhesive layer 22. In detail, the die bond sheet 10 is overlaid on the adhesive layer 22 in a state in which the release sheet and the die bond sheet 10 are laminated, and after overlaying, the release sheet is peeled off (transferred), so that the die bond sheet 10 can be overlaid on the adhesive layer 22.

The die bond sheet 10 of this embodiment is configured as described above, which can prevent chips (dies) from floating when stacked.

Next, we will explain an embodiment of the dicing die bond film according to the present invention.

The dicing die bond film 1 of this embodiment comprises the above-mentioned die bond sheet 10 and a dicing tape attached to the die bond sheet 10.

<Dicing tape for dicing die bond film>
The dicing tape 20 is usually a long sheet and is stored in a rolled state until it is used. The dicing die bond film 1 of the present embodiment is stretched on an annular frame having an inner diameter slightly larger than the silicon wafer to be cut, and is used after being cut.

The dicing tape 20 includes a base layer 21 and an adhesive layer 22 superimposed on the base layer 21.

The base layer 21 may have a single-layer structure or a laminated structure.
Each layer of the base material layer 21 is, for example, a metal foil, a fiber sheet such as paper or cloth, a rubber sheet, or a resin film.
Examples of the fiber sheet constituting the base material layer 21 include paper, woven fabric, and nonwoven fabric.
Examples of materials for the resin film include polyolefins such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymers; ethylene copolymers such as ethylene-vinyl acetate copolymers (EVA), ionomer resins, ethylene-(meth)acrylic acid copolymers, and ethylene-(meth)acrylic acid ester (random, alternating) copolymers; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyacrylates; polyvinyl chloride (PVC); polyurethanes; polycarbonates; polyphenylene sulfide (PPS); polyamides such as aliphatic polyamides and fully aromatic polyamides (aramids); polyether ether ketones (PEEK); polyimides; polyetherimides; polyvinylidene chloride; ABS (acrylonitrile-butadiene-styrene copolymers); cellulose or cellulose derivatives; silicone-containing polymers; and fluorine-containing polymers. These may be used alone or in combination of two or more.

The base layer 21 is preferably made of a polymeric material such as a resin film.
When the base layer 21 has a resin film, the resin film may be subjected to a stretching process or the like to control the deformability such as elongation percentage.
The surface of the base layer 21 may be subjected to a surface treatment in order to enhance adhesion with the pressure-sensitive adhesive layer 22. Examples of the surface treatment that can be used include oxidation treatment by chemical or physical methods such as chromate treatment, ozone exposure, flame exposure, high-voltage shock exposure, and ionizing radiation treatment. In addition, the base layer 21 may be subjected to a coating treatment using a coating agent such as an anchor coating agent, a primer, or an adhesive.

The substrate layer 21 is preferably composed of multiple layers, more preferably composed of at least three layers, and even more preferably composed of three layers.

The three-layered base layer 21 preferably has two non-elastomer layers (X, X) made of a non-elastomer, and an elastomer layer (Y) disposed between the two non-elastomer layers and made of an elastomer (X-layer/Y-layer/X-layer).
The elastomer layer is a layer having an elastic modulus of 200 MPa or less at room temperature. The elastomer layer is usually formed of a polymer material that exhibits rubber elasticity at room temperature (23° C.). On the other hand, the non-elastomer layer is a layer having an elastic modulus of more than 200 MPa at room temperature.
Each layer of the elastomer having such a three-layer laminate structure is usually formed of a resin. The elastomer having the three-layer laminate structure is produced, for example, by coextrusion molding, and the three layers are integrated together.

In the three-layered base layer 21, the ratio of the thickness of the inner layer to the thickness of one outer layer (Y thickness/X thickness) is preferably 5 or more and 15 or less.

It is preferable that the non-elastomer layer disposed on the outside has a molecular weight distribution dispersity (mass average molecular weight/number average molecular weight) of 3 or less when the constituent resin is measured by GPC.

The non-elastomer layer (X) may contain low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, etc. Examples of polypropylene include homopolymers (homopolypropylene) and copolymers such as random polypropylene and block polypropylene. The polypropylene may be metallocene polypropylene synthesized by a metallocene catalyst. The non-elastomer layer (X) preferably contains metallocene polypropylene.

On the other hand, the elastomer layer (Y) preferably contains an ethylene-vinyl acetate copolymer (EVA) or an α-olefin-based thermoplastic elastomer, and more preferably contains an ethylene-vinyl acetate copolymer (EVA). Examples of the α-olefin-based thermoplastic elastomer include a homopolymer of an α-olefin and a copolymer of two or more kinds of α-olefins.
The ethylene-vinyl acetate copolymer resin (EVA) may contain 5% by mass or more and 35% by mass or less of vinyl acetate structural units.

The thickness (total thickness) of the base layer 21 may be 80 μm or more and 150 μm or less.

The back side of the base layer 21 (the side on which the adhesive layer 22 is not overlapped) may be subjected to a release treatment using a release agent (release agent) such as a silicone-based resin or a fluorine-based resin in order to impart releasability.
The base layer 21 is preferably a light-transmitting (ultraviolet ray-transmitting) resin film or the like, since this allows active energy rays such as ultraviolet ray to be applied to the pressure-sensitive adhesive layer 22 from the back side.

The dicing tape 20 may be provided with a release sheet that covers one side of the adhesive layer 22 (the side where the adhesive layer 22 does not overlap the base layer 21) before use. When a die bond sheet 10 having an area smaller than the adhesive layer 22 is arranged so as to fit within the adhesive layer 22, the release sheet is arranged so as to cover both the adhesive layer 22 and the die bond sheet 10. The release sheet is used to protect the adhesive layer 22, and is peeled off before attaching the die bond sheet 10 to the adhesive layer 22.

As the release sheet, for example, a plastic film or paper that has been surface-treated with a release agent such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent can be used.
Furthermore, examples of the release sheet that can be used include films made of fluorine-based polymers such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymers, and chlorofluoroethylene-vinylidene fluoride copolymers; films made of polyolefins such as polyethylene and polypropylene; and films made of polyesters such as polyethylene terephthalate (PET).
As the release sheet, for example, a plastic film or paper whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent can be used.
The release sheet can be used as a support material for supporting the adhesive layer 22. In particular, the release sheet is preferably used when the adhesive layer 22 is overlaid on the base layer 21. In detail, the adhesive layer 22 is overlaid on the base layer 21 in a state where the release sheet and the adhesive layer 22 are laminated, and after overlaying, the release sheet is peeled off (transferred), thereby overlaying the adhesive layer 22 on the base layer 21.

In this embodiment, the pressure-sensitive adhesive layer 22 contains, for example, an acrylic polymer, an isocyanate compound, and a polymerization initiator.
The pressure-sensitive adhesive layer 22 may have a thickness of 5 μm or more and 40 μm or less. The shape and size of the pressure-sensitive adhesive layer 22 are usually the same as the shape and size of the base layer 21.

The acrylic polymer has at least an alkyl (meth)acrylate structural unit, a hydroxyl group-containing (meth)acrylate structural unit, and a polymerizable group-containing (meth)acrylate structural unit in the molecule. The structural units are units that constitute the main chain of the acrylic polymer. Each side chain in the acrylic polymer is included in each structural unit that constitutes the main chain.
In this specification, the term "(meth)acrylate" refers to at least one of methacrylate (methacrylic acid ester) and acrylate (acrylic acid ester). Similarly, the term "(meth)acrylic acid" refers to at least one of methacrylic acid and acrylic acid.

In the acrylic polymer contained in the pressure-sensitive adhesive layer 22, the above-mentioned structural units can be confirmed by NMR analysis such as ¹ H-NMR and ¹³ C-NMR, pyrolysis GC/MS analysis, infrared spectroscopy, etc. The molar ratio of the above-mentioned structural units in the acrylic polymer is usually calculated from the blending amount (charge amount) when the acrylic polymer is polymerized.

The above alkyl (meth)acrylate structural unit is derived from an alkyl (meth)acrylate monomer. In other words, the molecular structure after the alkyl (meth)acrylate monomer is polymerized is the alkyl (meth)acrylate structural unit. The term "alkyl" refers to the number of carbon atoms in the hydrocarbon portion ester-bonded to the (meth)acrylic acid.
The hydrocarbon portion of the alkyl portion in the structural unit of the alkyl (meth)acrylate may be a saturated hydrocarbon or an unsaturated hydrocarbon.
In addition, it is preferable that the alkyl portion does not contain a polar group containing oxygen (O) or nitrogen (N). This can prevent the polarity of the alkyl polymer from increasing excessively. Therefore, the adhesive layer 22 is prevented from having excessive affinity with the die bond sheet 10. Therefore, the dicing tape 20 can be more satisfactorily peeled off from the die bond sheet 10. The number of carbon atoms in the alkyl portion may be 6 or more and 10 or less.

Examples of constituent units of alkyl (meth)acrylate include hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n- or iso-nonyl (meth)acrylate, and decyl (meth)acrylate.

The acrylic polymer has a hydroxyl group-containing (meth)acrylate structural unit, and the hydroxyl group of such a structural unit easily reacts with an isocyanate group.
By allowing the acrylic polymer having a hydroxyl group-containing (meth)acrylate structural unit and the isocyanate compound to coexist in the pressure-sensitive adhesive layer 22, the pressure-sensitive adhesive layer 22 can be appropriately cured. Therefore, the acrylic polymer can be sufficiently gelled. Therefore, the pressure-sensitive adhesive layer 22 can exhibit adhesive performance while maintaining its shape.

The structural unit of the hydroxyl group-containing (meth)acrylate is preferably a structural unit of a hydroxyl group-containing C2-C4 alkyl (meth)acrylate. The term "C2-C4 alkyl" refers to the number of carbon atoms in the hydrocarbon moiety that is ester-bonded to the (meth)acrylic acid. In other words, the hydroxyl group-containing C2-C4 alkyl (meth)acrylate monomer refers to a monomer in which (meth)acrylic acid is ester-bonded to an alcohol having 2 to 4 carbon atoms (usually a dihydric alcohol).
The hydrocarbon portion of the C2-C4 alkyl is usually a saturated hydrocarbon. For example, the hydrocarbon portion of the C2-C4 alkyl is a linear saturated hydrocarbon or a branched saturated hydrocarbon. It is preferable that the hydrocarbon portion of the C2-C4 alkyl does not contain a polar group containing oxygen (O), nitrogen (N), or the like.

Examples of structural units of hydroxyl-containing C2-C4 alkyl (meth)acrylate include structural units of hydroxybutyl (meth)acrylate, such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxy n-butyl (meth)acrylate, or hydroxy iso-butyl (meth)acrylate. In the structural unit of hydroxybutyl (meth)acrylate, the hydroxyl group (-OH group) may be bonded to the carbon (C) at the end of the hydrocarbon portion, or to a carbon (C) other than the end of the hydrocarbon portion.

The acrylic polymer contains a structural unit of a polymerizable group-containing (meth)acrylate having a polymerizable unsaturated double bond in the side chain.
Since the acrylic polymer contains a structural unit of a polymerizable group-containing (meth)acrylate, the adhesive layer 22 can be cured by irradiation with active energy rays (such as ultraviolet rays) before the pick-up step. In particular, the irradiation with active energy rays such as ultraviolet rays generates radicals from the photopolymerization initiator, and the acrylic polymers can be crosslinked by the action of these radicals. This allows the adhesive strength of the adhesive layer 22 before irradiation to be reduced by irradiation. Then, the die bond sheet 10 can be peeled off well from the adhesive layer 22.
The active energy rays include ultraviolet rays, radioactive rays, and electron beams.

Specifically, the structural unit of the polymerizable group-containing (meth)acrylate may have a molecular structure in which an isocyanate group of an isocyanate group-containing (meth)acrylate monomer is urethane-bonded to a hydroxyl group in the structural unit of the hydroxyl group-containing (meth)acrylate described above.

The structural unit of the polymerizable group-containing (meth)acrylate having a polymerizable group can be prepared after polymerization of the acrylic polymer. For example, after copolymerization of an alkyl (meth)acrylate monomer with a hydroxyl group-containing (meth)acrylate monomer, the hydroxyl group in a part of the structural unit of the hydroxyl group-containing (meth)acrylate and the isocyanate group of the isocyanate group-containing polymerizable monomer are reacted to form a urethane reaction, thereby obtaining the structural unit of the polymerizable group-containing (meth)acrylate.

The above-mentioned isocyanate group-containing (meth)acrylate monomer preferably has one isocyanate group and one (meth)acryloyl group in the molecule. An example of such a monomer is 2-isocyanatoethyl (meth)acrylate.

The adhesive layer 22 of the dicing tape 20 in this embodiment further contains an isocyanate compound. A part of the isocyanate compound may be in a state after being reacted by a urethane reaction or the like.
The isocyanate compound has a plurality of isocyanate groups in the molecule. The isocyanate compound has a plurality of isocyanate groups in the molecule, which allows a crosslinking reaction between the acrylic polymers in the pressure-sensitive adhesive layer 22 to proceed. In detail, one isocyanate group of the isocyanate compound is reacted with a hydroxyl group of an acrylic polymer, and the other isocyanate group is reacted with a hydroxyl group of another acrylic polymer, allowing a crosslinking reaction via the isocyanate compound to proceed.

Examples of isocyanate compounds include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates.

Further examples of isocyanate compounds include polymerized polyisocyanates such as diisocyanate dimers and trimers, and polymethylene polyphenylene polyisocyanates.

In addition, the isocyanate compound may be, for example, a polyisocyanate obtained by reacting an excess amount of the above-mentioned isocyanate compound with an active hydrogen-containing compound. Examples of the active hydrogen-containing compound include an active hydrogen-containing low molecular weight compound and an active hydrogen-containing high molecular weight compound.
As the isocyanate compound, allophanated polyisocyanate, biuretized polyisocyanate, etc. can also be used.
The above isocyanate compounds may be used alone or in combination of two or more.

The above-mentioned isocyanate compound is preferably a reaction product of an aromatic diisocyanate and an active hydrogen-containing low molecular weight compound. The reaction rate of the isocyanate group in the reaction product of an aromatic diisocyanate is relatively slow, so that the pressure-sensitive adhesive layer 22 containing such a reaction product is prevented from being excessively hardened. The above-mentioned isocyanate compound is preferably one having three or more isocyanate groups in the molecule.

The polymerization initiator contained in the adhesive layer 22 is a compound that can initiate a polymerization reaction by the energy of heat or light applied. By containing the polymerization initiator in the adhesive layer 22, when heat energy or light energy is applied to the adhesive layer 22, a crosslinking reaction between acrylic polymers can be promoted. In detail, a polymerization reaction between polymerizable groups between acrylic polymers having a structural unit of a polymerizable group-containing (meth)acrylate can be initiated to harden the adhesive layer 22. This reduces the adhesive force of the adhesive layer 22, and in the pick-up process, the die bond sheet 10 can be easily peeled off from the hardened adhesive layer 22.
As the polymerization initiator, for example, a photopolymerization initiator or a thermal polymerization initiator is used. As the polymerization initiator, a general commercially available product can be used.

The adhesive layer 22 may further contain other components in addition to the components described above. Examples of the other components include tackifiers, plasticizers, fillers, antioxidants, antioxidants, UV absorbers, light stabilizers, heat stabilizers, antistatic agents, surfactants, and light release agents. The types and amounts of the other components used may be appropriately selected depending on the purpose.

Next, we will explain the manufacturing method of the die bond sheet 10 and dicing die bond film 1 of this embodiment.

<Dicing die bond film manufacturing method>
The manufacturing method of the dicing die bond film 1 of this embodiment is as follows:
A step of producing a die bond sheet 10;
A step of preparing a dicing tape 20;
The method includes a step of overlapping the manufactured die bond sheet 10 and the dicing tape 20.

<Step of Producing Die Bond Sheet>
The process of producing the die bond sheet 10 includes the following steps:
A resin composition preparation step of preparing a resin composition for forming the die bond sheet 10;
and a die-bonding sheet forming step of forming the die-bonding sheet 10 from the resin composition.

In the resin composition preparation process, for example, an epoxy resin, an epoxy resin curing catalyst, an acrylic resin, a phenolic resin, a solvent, etc. are mixed and each resin is dissolved in the solvent to prepare the resin composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Commercially available products can be used as these resins.

In the die bond sheet forming process, for example, the resin composition prepared as described above is applied to a release sheet. The application method is not particularly limited, and general application methods such as roll coating, screen coating, and gravure coating are used. Next, if necessary, the applied composition is solidified by a desolvation process or a curing process to form the die bond sheet 10.

<Process for producing dicing tape>
The process for producing the dicing tape includes the following steps:
A synthesis step of synthesizing an acrylic polymer;
A pressure-sensitive adhesive layer preparation step of preparing a pressure-sensitive adhesive layer 22 by volatilizing a solvent from a pressure-sensitive adhesive composition containing the above-mentioned acrylic polymer, an isocyanate compound, a polymerization initiator, a solvent, and other components that are appropriately added depending on the purpose;
a base material layer preparation step of preparing a base material layer 21;
The method includes a lamination step of laminating the adhesive layer 22 and the base layer 21 together to laminate the base layer 21 and the adhesive layer 22 together.

In the synthesis step, for example, a C9 to C11 alkyl (meth)acrylate monomer and a hydroxyl group-containing (meth)acrylate monomer are radically polymerized to synthesize an acrylic polymer intermediate.
The radical polymerization can be carried out by a general method. For example, the above-mentioned monomers are dissolved in a solvent, stirred under heating, and a polymerization initiator is added to synthesize an acrylic polymer intermediate. In order to adjust the molecular weight of the acrylic polymer, the polymerization may be carried out in the presence of a chain transfer agent.
Next, some of the hydroxyl groups of the hydroxyl group-containing (meth)acrylate structural units contained in the acrylic polymer intermediate are bonded to the isocyanate groups of the isocyanate group-containing polymerizable monomer by a urethane reaction, whereby some of the hydroxyl group-containing (meth)acrylate structural units become polymerizable group-containing (meth)acrylate structural units.
The urethane reaction can be carried out by a general method. For example, the acrylic polymer intermediate and the isocyanate group-containing polymerizable monomer are stirred while being heated in the presence of a solvent and a urethane catalyst. This allows the isocyanate group of the isocyanate group-containing polymerizable monomer to be urethane-bonded to a part of the hydroxyl groups of the acrylic polymer intermediate.

In the adhesive layer preparation process, for example, an acrylic polymer, an isocyanate compound, and a polymerization initiator are dissolved in a solvent to prepare an adhesive composition. The viscosity of the composition can be adjusted by changing the amount of solvent. Next, the adhesive composition is applied to a release sheet. As the application method, for example, a general application method such as roll coating, screen coating, or gravure coating is adopted. The applied composition is subjected to a solvent removal process, a solidification process, or the like to solidify the applied adhesive composition, thereby preparing the adhesive layer 22.

In the substrate layer preparation process, the substrate layer can be prepared by film formation using a general method. Examples of the film formation method include a calendar film formation method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, and a dry lamination method. A co-extrusion molding method may also be used. Note that a commercially available film or the like may be used as the substrate layer 21.

In the lamination step, the pressure-sensitive adhesive layer 22 overlapping the release sheet is laminated on the base layer 21. The release sheet may remain overlapping the pressure-sensitive adhesive layer 22 until use.
In addition, in order to promote the reaction between the crosslinking agent and the acrylic polymer and also between the crosslinking agent and the surface portion of the base material layer 21, an aging treatment step may be carried out for 48 hours in an environment of 50°C after the lamination step.

Through these steps, the dicing tape 20 can be manufactured.

<Step of overlapping the die bond sheet 10 and the dicing tape 20>
In the step of overlapping the die bond sheet 10 and the dicing tape 20, the die bond sheet 10 is attached to the adhesive layer 22 of the dicing tape 20 manufactured as described above.

In this attachment, the release sheets are peeled off from the adhesive layer 22 of the dicing tape 20 and the die bond sheet 10, respectively, and the two are attached together so that the die bond sheet 10 and the adhesive layer 22 are in direct contact with each other. For example, the two can be attached by pressure bonding. The temperature during attachment is not particularly limited, and is, for example, 30°C to 50°C, and preferably 35°C to 45°C. The linear pressure during attachment is not particularly limited, but is preferably 0.1 kgf/cm to 20 kgf/cm, and more preferably 1 kgf/cm to 10 kgf/cm.

The dicing die bond film 1 manufactured as described above through the above-mentioned process is used, for example, as an auxiliary tool for manufacturing semiconductor integrated circuits. Specific examples of its use are described below.

<Method of using dicing die bond film when manufacturing semiconductor integrated circuits>
A method for manufacturing a semiconductor integrated circuit generally includes a process of cutting out chips from a semiconductor wafer having a circuit surface formed thereon, and assembling the chips.
This process includes, for example, 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, and the semiconductor wafer is further ground to reduce its thickness, a mounting process in which one side (for example, the side opposite to the circuit side) of the half-cut semiconductor wafer is attached to the die bond sheet 10 and the semiconductor wafer is fixed to the dicing tape 20, an expanding process in which the interval between the half-cut semiconductor chips is widened, a pick-up process in which the die bond sheet 10 and the adhesive layer 22 are peeled off to take out the semiconductor chip (die) with the die bond sheet 10 attached, and a die bond process in which the semiconductor chip (die) with the die bond sheet 10 attached is attached to an adherend. When these processes are carried out, the dicing tape (dicing die bond film) of this embodiment is used as a manufacturing auxiliary tool.

In the half-cut process, as shown in Figures 2A to 2D, half-cut processing is performed to split the semiconductor integrated circuit into small pieces (dies). More specifically, a wafer processing tape T is attached to the surface of the semiconductor wafer opposite the circuit surface. A dicing ring R is also attached to the wafer processing tape T. With the wafer processing tape T attached, grooves for division are formed. A backgrind tape G is attached to the surface with the grooves formed, while the wafer processing tape T that was initially attached is peeled off. With the backgrind tape G attached, the semiconductor wafer is ground until it reaches a specified thickness.

In the mounting process, as shown in Figures 3A and 3B, a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, and a half-cut semiconductor wafer is attached to the exposed surface of the die bond sheet 10. Then, the backgrind tape G is peeled off from the semiconductor wafer.

In the expanding process, as shown in Figures 4A to 4C, a dicing ring R is attached to the adhesive layer 22 of the dicing tape 20, and then fixed to the holder H of the expanding device. The dicing die bond film 1 is stretched so as to expand in the surface direction by pushing up the push-up member U equipped in the expanding device from the underside of the dicing die bond film 1. As a result, the half-cut semiconductor wafer is broken under specific temperature conditions. The above temperature conditions are, for example, -20 to 0°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 (up to this point is the low-temperature expanding process). Furthermore, in the expanding process, as shown in Figures 5A to 5B, the dicing tape 20 is stretched so as to expand the area under higher temperature conditions (for example, 10°C to 25°C). This separates adjacent cleaved semiconductor chips in the planar direction of the film surface, further widening the kerf (spacing) (room temperature expansion process).

In the pick-up process, as shown in FIG. 6, the semiconductor chip with the die bond sheet 10 attached thereto is peeled off from the adhesive layer 22 of the dicing tape 20. More specifically, the pin member P is raised to push up the semiconductor chip to be picked up through the dicing tape 20. The pushed-up semiconductor chip is held by the suction jig J.

In the die bonding step, the semiconductor chip with the die bonding sheet 10 attached thereto is bonded to an adherend.
In the die bonding process, as shown in FIG. 7, semiconductor chips with die bonding sheets 10 attached thereto may be stacked multiple times.
In the first bonding, the die bond sheet 10 is bonded to the substrate Z, but in the second and subsequent bonding, the die bond sheet 10 is bonded to the surface (circuit surface) of the semiconductor chip. The surface of the semiconductor chip is coated with a specific resin (e.g., polyimide resin). Therefore, the adhesive performance of the die bond sheet 10 to the surface of the semiconductor chip may be affected by the above-mentioned coating process.
In this embodiment, it has been found that the adhesive performance is related to the peeling force of the die bond sheet 10 from the polyimide resin surface. Furthermore, it has been found that the adhesive performance is also related to the surface free energy of the die bond sheet 10.

In recent years, with the further development of integration technology in the semiconductor industry, thinner semiconductor chips (e.g., thicknesses of 20 μm to 50 μm) are in demand. An electronic circuit is formed on one surface of such a thin semiconductor chip. If an electronic circuit is formed on one surface of a thin semiconductor chip, the semiconductor chip may not be able to withstand internal stress and may become slightly deformed (warped, etc.). If such a semiconductor chip is stacked multiple times as described above with the die bond sheet 10 attached, as shown in FIG. 7, for example, so-called floating may occur due to poor adhesion between the die bond sheet and the chip (die). In this embodiment, the die bond sheet 10 has specific physical properties, so that such floating can be suppressed.

The die bond sheet and dicing die bond film of this embodiment are as exemplified above, but the present invention is not limited to the die bond sheet and dicing die bond film exemplified above.
That is, various forms used in general die bond sheets and dicing die bond films can be adopted within the scope that does not impair the effects of the present invention.

The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these.

A die bond sheet was produced as follows. This die bond sheet was then attached to a dicing tape to produce a dicing die bond film.

<Preparation of die bond sheet>
The raw materials having the composition shown in Table 1 were added to methyl ethyl ketone and mixed to obtain a composition for die-bonding sheet having a solid content concentration of 40 mass %. Details of each raw material are shown below.
・Silica filler: Admatechs Co., Ltd., raw material name "SO-E2"
- Acrylic resin: Nagase ChemteX Corporation
Raw material name: "Teisan Resin SG-280 EK23" (containing -COOH group)
Raw material name: "Teisan Resin SG-708-6" (containing -COOH and -OH groups)
Raw material name: "Teisan Resin SG-P3" (containing glycidyl groups)
・Epoxy resin: Nippon Kayaku Co., Ltd., raw material name "EPPN-501HY" (trisphenolmethane type)
DIC Corporation Raw material name "HP-7200L" (dicyclopentadiene type)
DIC Corporation Raw material name "N-665-EXP-S" (cresol novolac type)
Phenolic resin: Meiwa Kasei Co., Ltd., raw material name "H-4" (novolac type)
・Curing catalyst: Manufactured by Hokko Chemical Co., Ltd. Raw material name “TPP-K”
Next, the die-bonding sheet composition was applied to one side of the release sheet (the silicone-treated side of the PET sheet with a thickness of 50 μm) using an applicator. The application was performed so that the thickness after drying was 40 μm, and then the solvent was evaporated from the die-bonding sheet composition by drying at 130 ° C for 2 minutes. In this way, a die-bonding sheet overlapping the release sheet was obtained.

<Base layer of dicing tape>
The products shown below were used as raw materials to prepare a substrate layer having three laminated layers.
Resin that constitutes the inner layer (or the single base layer) Raw material name: Ultrathene 751
Ethylene-vinyl acetate copolymer resin (EVA containing 28% vinyl acetate by mass)
Resin that composes the outer layer, manufactured by Tosoh Corporation. Raw material name: WINTEC WFX4M
Metallocene polypropylene manufactured by Japan Polypropylene Corporation

(Forming of substrate layer)
The substrate layer was molded using an extrusion T-die molding machine. The extrusion temperature was 190° C. The substrate layers of the three-layer laminate type were integrated by co-extrusion molding from a T-die. After the integrated substrate layer (laminate) was sufficiently solidified, the substrate layer was wound into a roll and stored.
The thickness ratio of each layer constituting the base layer and the total thickness of the base layer are as shown in Table 1.

<Adhesive layer of dicing tape>
(Preparation of Pressure-Sensitive Adhesive Layer (Pressure-Sensitive Adhesive Composition))
The following raw materials were mixed to prepare a first resin composition.
INA (isononyl acrylate) 173 parts by mass HEA (hydroxyethyl acrylate) 54.5 parts by mass AIBN (2,2'-azobisisobutyronitrile) 0.46 parts by mass Ethyl acetate 372 parts by mass Next, the first resin composition was placed in 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. While stirring the first resin composition, the liquid temperature of the first resin composition was adjusted to room temperature (23 ° C.), and the inside of the round-bottom separable flask was replaced with nitrogen gas for 6 hours.
Next, while nitrogen gas was flowing into the round-bottom separable flask, the first resin composition was stirred and the liquid temperature of the first resin composition was kept at 62° C. for 3 hours. Thereafter, the mixture was further kept at 75° C. for 2 hours to carry out the polymerization reaction of the INA, HEA, and AIBN, thereby preparing the second resin composition. Thereafter, the flow of nitrogen gas into the round-bottom separable flask was stopped.
After the second resin composition was cooled to room temperature, the following raw materials were added to the second resin composition to prepare a third resin composition.
2-Methacryloyloxyethyl isocyanate (a compound having a polymerizable carbon-carbon double bond; raw material name "Karenz MOI", manufactured by Showa Denko K.K.) 52.5 parts by mass Dibutyltin dilaurate IV (manufactured by Wako Pure Chemical Industries, Ltd.) 0.26 parts by mass The obtained third resin composition was stirred at 50°C for 24 hours under an atmospheric air.
Finally, the following raw materials were added to 100 parts by mass of the polymer solid content of the third resin composition.
Isocyanate compound (raw material name "Coronate L", manufactured by Tosoh Corporation): 0.75 parts by mass Photopolymerization initiator (raw material name "Omnirad 127", manufactured by IGM Resins): 2 parts by mass Then, the third resin composition was diluted with ethyl acetate so that the solid content concentration was 20 mass%, thereby preparing a pressure-sensitive adhesive composition.

<Preparation of dicing tape>
The adhesive composition was applied to one surface of the base layer using an applicator to a thickness of 10 μm. The base layer after the adhesive composition application was heated and dried at 110° C. for 3 minutes to form an adhesive layer, thereby producing a dicing tape.

<Production of dicing die bond film>
(Laminating the die bond sheet and dicing tape)
The adhesive layer of the dicing tape was attached to the die bond sheet (the side on which the release sheet was not laminated) of the die bond sheet. Then, the release sheet was peeled off from the die bond sheet to prepare a dicing die bond film including the die bond sheet.

In this manner, the die bond sheets and dicing die bond films of the examples and comparative examples were manufactured according to the above-mentioned methods. Details of each die bond sheet are shown in Table 1.

(Peeling force of die bond sheet from polyimide resin surface)
In each of the dicing die bond films of the Examples and Comparative Examples, the peel strength of one surface of the die bond sheet (the surface to which the release sheet was attached) was measured.
In detail, first, the release sheet attached to the die bond sheet was removed, and the newly appeared surface of the die bond sheet (the surface to be bonded to the semiconductor chip later) was bonded to one surface of a polyimide resin film (Kapton 100H: manufactured by Toray DuPont Co., Ltd.). The bonding was performed under conditions of 60°C and 10 mm/sec. Then, using a hand roller, a backing tape (product name: BT-315 (manufactured by Nitto Denko Corporation)) was bonded to the other surface of the polyimide resin film (the surface opposite to the surface to which the DAF was bonded) at 23°C. Then, a measurement sample was prepared by cutting to a width of 50 mm, and the peel force was measured at a peel angle of 180° and a peel speed of 300 mm/min under an atmosphere of 23°C. An autograph (manufactured by Shimadzu Corporation) was used as the measuring device.

(Method for measuring surface free energy of die bond sheet)
In each of the dicing die bond films of the Examples and Comparative Examples, the surface free energy of one surface of the die bond sheet (the surface to which the release sheet was attached) was measured.
The contact angles of water and methylene iodide were measured, and the average of five measurements was used. Note that a FAMAS (manufactured by Kyowa Corporation) was used as the measuring device, and 1 mL of the liquid was dropped onto the surface, and the contact angle was measured within 5 seconds.
The dispersive component and the polar component were calculated from each measured value of the contact angle, and the surface free energy was calculated by the sum of the calculated components. The method for calculating the surface free energy was as described above.

(Preparation of warped wafers for performance evaluation)
In the "evaluation of lifting from chip" described later, in order to evaluate using a wafer that is prone to lifting, a "warped wafer" was produced as follows.
First, the following components (a) to (f) were dissolved in methyl ethyl ketone to obtain a warpage adjusting composition having a solid content concentration of 20% by mass.
(a) Acrylic resin (manufactured by Nagase Chemtex Corporation, raw material name "SG-70L"): 5 parts by weight (b) Epoxy resin (manufactured by Mitsubishi Chemical Corporation, raw material name "JER828"): 5 parts by weight (c) Phenol resin (manufactured by Meiwa Kasei Co., Ltd., raw material name "LDR8210"): 14 parts by weight (d) Epoxy resin (manufactured by Mitsubishi Chemical Corporation, raw material name "MEH-8005"): 2 parts by weight (e) Spherical silica (manufactured by Admatechs Co., Ltd., raw material name "SO-25R"): 53 parts by weight (f) Phosphorus-based catalyst (TPP-K): 1 part by weight Next, the warpage adjustment composition was applied to one side of the release sheet (the silicone-treated side of a PET-based sheet having a thickness of 50 μm) using an applicator to a thickness of 25 μm. A drying process was carried out at 130 ° C. for 2 minutes to volatilize the solvent from the warpage adjustment composition. This produced a warpage-controlling sheet in which the warpage-controlling layer was superimposed on the release sheet.
Next, a bare wafer was attached to the warpage adjusting layer of the warpage adjusting sheet (on the side opposite to the release sheet). The attachment was performed using a laminator (manufactured by MCK Corporation, model MRK-600) under conditions of 60°C, 0.1 MPa, and 10 mm/s. After attachment, the wafer was placed in an oven and heat-treated at 175°C for 1 hour to harden the warpage adjusting layer. This caused the warpage adjusting layer to shrink, resulting in a warped bare wafer.
After shrinking the warpage adjustment layer as described above, a wafer processing tape (manufactured by Nitto Denko Corporation, product name "V-12SR2") was attached to the exposed side of the warped bare wafer (the side to which the warpage adjustment layer was not attached). Then, a dicing ring was fixed to the warped bare wafer via the wafer processing tape. Then, the warpage adjustment layer was removed from the warped bare wafer.
A dicing device (manufactured by DISCO, model number 6361) was used to form 100 μm deep grooves in a lattice pattern (20 μm wide) over the entire surface of one side of the warped bare wafer (the surface from which the warpage adjustment layer had been removed).
A backgrind tape was applied to the one surface of the warped bare wafer, while the wafer processing tape was removed from the other surface of the warped bare wafer.
The warped bare wafer was ground from the other side using a back grinder (manufactured by DISCO, model DGP8760) so that the thickness of the warped bare wafer was 55 μm (0.055 mm), thereby obtaining a "warped wafer."

(Performance evaluation regarding lifting of die bond sheet from semiconductor chip)
A semiconductor chip with a die bond sheet was obtained from the "warped wafer" through the expanding process. The semiconductor chip with the die bond sheet attached was picked up from the dicing tape and then die-bonded to a lead frame via the die bond sheet.
Next, the semiconductor chip with the die bond sheet obtained through the above-mentioned expanding process was picked up from the dicing tape, and then die-bonded to the semiconductor chip on the lead frame via the die bond sheet. In other words, the semiconductor chips with the die bond sheet were stacked.
When stacking the semiconductor chips (square in plan view) with the die bond sheet, the position of the upper semiconductor chip was shifted so that they were not completely overlapped when viewed from above, and die bonding was performed. The position shift direction was the extension direction of one side of the semiconductor chip, and the position shift length was 200 μm. Thereafter, the same stacking die bonding was repeated five more times. Note that in each die bonding, the direction of the above-mentioned position shift (position shift length 200 μm) was the same direction. Also, each die bonding was performed under the conditions of 100° C., pressure of 0.2 MPa, and pressure time of 2 seconds.
In the die bonding process, when the semiconductor chips were stacked in seven layers (at the time of the seventh die bonding), all the semiconductor chips were observed, and when none of the die bond sheets were lifted from the semiconductor chips, the performance of the lift suppression was evaluated as good (◯). On the other hand, when even one die bond sheet was lifted from the semiconductor chips, the performance of the lift suppression was evaluated as poor (×).

The contact angle was measured for the die bond sheets of each Example and Comparative Example, and the calculated surface free energy values and performance evaluation results (floating prevention performance) are shown in Table 1.

As can be seen from the above evaluation results, the dicing die bond film equipped with the die bond sheet of the embodiment was able to suppress the floating of the semiconductor chips when the semiconductor chips were stacked multiple times, compared to the dicing die bond film of the comparative example.

In the die bond sheet of the embodiment, the peel strength of the surface to be adhered to the adherend (with respect to the polyimide resin surface) is 0.1 N/50 mm or more, and the surface free energy is 35 mJ/ ^m2 or less.
By using the die bond sheet (dicing die bond film) of the embodiment having such physical properties in the manufacture of semiconductor integrated circuits, so-called NAND type flash memories and the like can be manufactured efficiently.

The die bond sheet and dicing die bond film of the present invention are suitable for use, for example, as auxiliary tools when manufacturing semiconductor integrated circuits.

1: Dicing die bond film,
10: Die bond sheet,
20: dicing tape,
21: Base material layer, 22: Adhesive layer.

Claims (3)

The peel strength from the polyimide resin surface is 0.1 N/50 mm or more,
The composition comprises an acrylic resin having an alkyl (meth)acrylate structural unit and a carboxyl group-containing monomer structural unit in the molecule, a trisphenolmethane or cresol novolac epoxy resin , a novolac phenolic resin, and a silica filler ;
A die bond sheet having a surface free energy of 35 mJ/m2 ^or less, and a proportion of the dispersion component of the surface free energy of 95% or more. 2. The die bond sheet according to claim 1 , which has a contact angle with water of 90° or more and a contact angle with methylene iodide of 50° or more. A dicing die bond film comprising the die bond sheet according to claim 1 or 2 and a dicing tape attached to the die bond sheet.