TWI868165B - Heat-resistant pressure-sensitive adhesive sheets for semiconductor device production - Google Patents

Abstract

The present invention relates to a heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices. The heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices of the present invention comprises: a substrate layer; and a first adhesive layer disposed on one side of the substrate layer, wherein the ratio of the 180° peeling adhesive force N2 of the first adhesive layer relative to a stainless steel plate after heating at 100-150°C, preferably 130°C for 3-10 minutes to the 180° peeling adhesive force N1 of the first adhesive layer relative to a stainless steel plate at 20-25°C, preferably 23°C, is N2/N1≤2, preferably N2/N1≤1.5. The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can be easily peeled off after use when used to temporarily fix a chip in a method for producing a substrate-free semiconductor package without using a metal lead frame, and no adhesive residue will occur on the encapsulation resin and the chip after encapsulation.

Description

Heat-resistant pressure-sensitive adhesive sheets for semiconductor device production

The present invention relates to a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, which is used for temporarily fixing a chip in a production method of a substrate-less semiconductor package body without using a metal lead frame; and a method for producing a semiconductor device using the pressure-sensitive adhesive sheet.

In recent years, CSP (Chip Size/Scale Package) technology has attracted much attention in LSI mounting technology. Among these technologies, WLP (Wafer Level Package) is a packaging form that uses only chips without using a substrate, which is particularly popular in terms of size reduction and high integration. According to the WLP production method, multiple semiconductor Si wafer chips arranged in an orderly manner without using a substrate are encapsulated as a whole with an encapsulation resin, and then cut into separate structures, thereby effectively producing a smaller package body than the conventional package body using a substrate.

The production method of this type of WLP requires that the chip, which is conventionally fixed to a substrate, be fixed to a separate support. Furthermore, the fixation must be released after the individual package is formed by resin encapsulation. Therefore, the support should not be permanently bonded but must be removable. From this point of view, there is a technology that uses pressure-sensitive adhesive tape as a support for temporarily fixing the chip.

Problem to be solved by the invention In a method for producing a substrate-less semiconductor package using a pressure-sensitive adhesive tape as a support for temporary fixing, due to the pressure when encapsulating with a resin, the chip is not supported by the pressure-sensitive adhesive tape and deviates from the specified position. In addition, due to the pressure when bonding the chip or when encapsulating with a resin, the chip is embedded in the pressure-sensitive adhesive tape, and a position difference (offset) occurs in which the chip surface becomes protruding relative to the encapsulating resin surface. In addition, due to the curing and heating of the encapsulating resin, the pressure-sensitive adhesive tape can become strongly bonded to the chip surface, and the package body will be damaged when the pressure-sensitive adhesive tape is peeled off, resulting in residual adhesive contamination.

Solution for solving the problem The inventors of the present invention have conducted in-depth research to solve the above-mentioned problem and found that the above-mentioned problem can be solved by using an adhesive layer with a specific adhesive force ratio, thereby completing the present invention.

That is, the present invention is as follows.

[1] A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, comprising: a substrate layer; and a first adhesive layer disposed on one side of the substrate layer, wherein the ratio of the 180° peeling adhesion N2 of the first adhesive layer relative to a stainless steel plate after heating at 100-150°C, preferably 130°C for 3-10 minutes to the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate at 20-25°C, preferably 23°C, is N2/N1≤2, preferably N2/N1≤1.5.

[2] The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as described in [1], wherein the first adhesive layer has a 180° peeling adhesion N1 of 0.1~3.0N/20mm, preferably 0.4~2.0N/20mm, relative to a stainless steel plate at 20~25°C, preferably 23°C; The first adhesive layer has a 180° peeling adhesion N2 of 0.2~6.0N/20mm, preferably 0.5~3.0N/20mm, relative to a stainless steel plate after being heated at 100~150°C, preferably 130°C for 3~10 minutes.

[3] A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as described in [1] or [2], wherein the first adhesive layer comprises an acrylic adhesive; the gelation rate of the first adhesive layer is greater than 70%; and/or the storage modulus G' of the first adhesive layer at 20-25°C, preferably 23°C, is 0.5×10 ⁵ -12×10 ⁵ Pa; and/or the weight average molecular weight of the soluble part of the acrylic adhesive is less than 80,000.

[4] A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as described in [1] or [2], wherein the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production also includes a second adhesive layer, wherein the second adhesive layer is disposed on a side of the substrate layer opposite to the first adhesive layer; preferably, the second adhesive layer is resistant to aging at 20-25°C, preferably 2 The 15° peeling adhesion to the stainless steel plate at 3°C is 2~100N/20mm, preferably 2~50N/20mm; After heating at 150°C for 4 hours, the 15° peeling adhesion of the second adhesive layer to the stainless steel plate is 3~130N/20mm, preferably 3~100N/20mm.

[5] The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production according to [4], wherein the second adhesive layer has a storage modulus G' of 0.8×10 ⁵ to 2.5×10 ⁵ Pa at 20 to 25°C, preferably 23°C; and the second adhesive layer has a storage modulus G' of 0.5×10 ⁵ to 1.6×10 ⁵ Pa at 150°C.

[6] In the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as described in [4], the gelation rate of the second adhesive layer is 40-90%; Preferably, the weight average molecular weight of the soluble part of the adhesive in the second adhesive layer is 2,000-6,000.

[7] The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production according to [1] or [2], wherein the substrate layer is at least one selected from the group consisting of polyester film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyamideimide film, polysulfone film, polyetherketone film, polytetrafluoroethylene film, ethylene-tetrafluoroethylene copolymer film, perfluoroethylene-propylene copolymer film, polyvinylidene fluoride film, polychlorotrifluoroethylene film and alternating copolymer film of ethylene and chlorotrifluoroethylene in a molar ratio of 1:1.

[8] The heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices as described in [4], wherein the heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices also includes a first release film and a second release film, wherein the first release film is disposed on a side of the first adhesive layer opposite to the substrate layer, and the second release film is disposed on a side of the second adhesive layer opposite to the substrate layer.

[9] The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as described in [4], wherein the thickness of the first adhesive layer is 5 to 50 μm; and the thickness of the second adhesive layer is 5 to 50 μm.

[10] A method for producing a semiconductor device, the method comprising using the heat-resistant pressure-sensitive adhesive sheet for producing a semiconductor device as described in any one of [1] to [9].

Effect of the invention The present invention provides a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, which is used as a pressure-sensitive adhesive sheet for temporarily fixing a chip in a production method of a substrate-free semiconductor package body that does not use a metal frame (for example, a WLP production method). The pressure-sensitive adhesive sheet of the present invention can support the chip so that the chip does not shift during the resin encapsulation step, thereby reducing the deviation of the chip from the specified position, and by embedding the chip in the pressure-sensitive adhesive layer with a small deviation, the pressure-sensitive adhesive sheet of the present invention can be easily peeled off after use. In addition, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can be easily peeled off after use without causing residual glue contamination to the encapsulation resin and the chip after encapsulation.

As a result of various studies to overcome the above problems, the inventors have found the following: When an adhesive layer having a ratio of the 180° peeling adhesion N2 of the first adhesive layer relative to a stainless steel plate after heating at 100 to 150°C, preferably 130°C for 3 to 10 minutes to the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate at 20 to 25°C, preferably 23°C, i.e., N2/N1≤2 is used as an adhesive layer used in a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, when a chip is encapsulated with a resin, the bonded chip does not deviate from a specified position, and degradation of position accuracy can be prevented. Furthermore, after encapsulation, the pressure-sensitive adhesive sheet can be peeled off without damaging the package body and without leaving any residue on the encapsulating resin.

[Heat-resistant pressure-sensitive adhesive sheet for semiconductor device production] The following specifically describes the implementation scheme of the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention with reference to FIG6. As shown in FIG6, the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention includes a base material layer 11 and a first adhesive layer 12.

In another embodiment, as shown in FIG. 7 , the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices may further include an adhesive layer, such as a second adhesive layer 13, for fixing the adhesive sheet to the metal substrate on a side opposite to the surface to be fixed and encapsulated with the chip.

In addition, in order to protect the surface of the adhesive layer in the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production before use, a release film may be provided on the surface of each adhesive layer. For example, a first release film 10 is provided on the side of the first adhesive layer opposite to the base layer, and a second release film 14 is provided on the side of the second adhesive layer opposite to the base layer.

<Base layer> The type of base layer is not particularly limited, but it is preferable to use a base material that has heat resistance under the heating conditions when encapsulating with the resin. The resin encapsulation step generally requires a temperature of about 175°C. From this point of view, it is preferable to use a material that has such heat resistance that no significant shrinkage occurs or the base layer itself does not collapse under such temperature conditions. For this reason, the material preferably has a linear thermal expansion coefficient of 0.8×10 ^-5 ~5.6×10 ^-5 /K at a temperature of 50~250°C.

In the case of using a substrate whose glass transition temperature is lower than the heating temperature for curing the encapsulation resin, the linear expansion coefficient in the temperature region higher than the glass transition temperature is larger than the linear expansion coefficient in the temperature region lower than the glass transition temperature, resulting in deterioration in the accuracy of the designated position of the bonded chip.

Furthermore, in a uniaxially or biaxially stretched substrate, at a temperature higher than the glass transition temperature, the elongation caused by the stretching begins to shrink, which leads to deterioration in the precision of the specified position of the bonded chip. For this reason, when the glass transition temperature of the substrate layer used in a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production used by being bonded to the chip exceeds 180°C when a substrate-less semiconductor chip without a metal lead frame is resin-encapsulated, the chip position precision can be improved.

Examples of the substrate are preferably selected from at least one of the group consisting of polyester film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyamideimide film, polysulfone film, polyetherketone film, polytetrafluoroethylene film, ethylene-tetrafluoroethylene copolymer film, perfluoroethylene-propylene copolymer film, polyvinylidene fluoride film, polychlorotrifluoroethylene film, alternating copolymer film of ethylene and chlorotrifluoroethylene in a molar ratio of 1:1, paper substrate (such as glass paper, high-quality paper and Japanese paper), non-woven fabric substrate (such as cellulose) and metal film substrate (such as aluminum foil, SUS foil and Ni foil).

The "glass transition temperature" used in the present invention refers to the temperature showing the peak of the loss tangent (tanδ) confirmed under the conditions of a heating rate of 5°C/min, a sample width of 5 mm, a chuck distance of 20 mm, and a frequency of 10 Hz in the DMA method (tensile method).

The substrate has a thickness of 5 to 200 μm, preferably 10 to 150 μm, and more preferably 20 to 100 μm. When the thickness is less than 5 μm, when the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production is peeled off after curing the encapsulation resin, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production is easily damaged and may not be peeled off, which reduces the handling property. A thickness exceeding 200 μm increases the cost, which is not preferred.

In addition, the substrate layer may be subjected to mold release using an organic silicon-based, fluorine-based, or long-chain alkyl-based release agent, antifouling treatment, acid treatment, alkali treatment, primer treatment, corona treatment, plasma treatment, or other adhesion-facilitating treatment, as needed.

<First adhesive layer> In the first adhesive layer used in the present invention, the adhesive is not particularly limited as long as it has heat resistance. From the viewpoint of heat resistance and cost, it is preferred that the first adhesive layer includes an acrylic adhesive.

An acrylic adhesive refers to an adhesive that uses an acrylic polymer as a base polymer (the main component of the polymer component, i.e., a component containing more than 50% by weight). There is no particular restriction on the content of the acrylic polymer in the first adhesive layer. From the perspective of obtaining sufficient bonding reliability in the first adhesive layer, it is preferably 60% by weight or more, more preferably 70% by weight or more, and further preferably 80% by weight or more relative to the total weight of the first adhesive layer (total weight, 100% by weight). By adjusting the content of the acrylic polymer in the acrylic adhesive to the above range, an adhesive layer having better stress relief and durability and excellent adhesion to the adherend can be provided.

The acrylic polymer disclosed herein is preferably a polymer of the following monomer components: the above monomer components include (meth) alkyl acrylate as a main monomer, and may further include other monomers copolymerizable with the above main monomer (copolymerizable monomers) as needed. The main monomer here refers to the main component of the monomer components constituting the acrylic polymer, that is, the component contained in the monomer components exceeding 50% by weight. In this specification, the term "(meth) alkyl acrylate" refers to alkyl acrylate and/or alkyl methacrylate.

The above-mentioned alkyl (meth)acrylate is a main monomer component used to constitute an acrylic polymer, and plays a role in expressing the basic characteristics of the adhesive (or adhesive layer), such as adhesiveness. The alkyl (meth)acrylate tends to impart softness to the acrylic polymer as a base polymer, and thus, has a tendency to exert the effect of making the first adhesive layer exhibit close adhesion and adhesiveness. The alkyl (meth)acrylate tends to impart hardness to the acrylic polymer as a base polymer, and thus, has a tendency to exert the effect of making the first adhesive layer exhibit re-peelability and force transmission.

The alkyl (meth)acrylate is preferably an alkyl (meth)acrylate in which the alkyl group has 4 to 20 carbon atoms. Specific examples of the alkyl (meth)acrylate having an alkyl group with 4 to 20 carbon atoms are not particularly limited, and include n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among them, n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) are preferred. The (meth)acrylic acid alkyl esters may be used alone or in combination of two or more.

The proportion of the (meth)acrylic acid alkyl ester in the monomer components constituting the acrylic polymer is preferably 90-95 parts by weight, based on 100 parts by weight of all the monomer components of the acrylic polymer. With such a monomer component composition, an adhesive sheet with excellent component retention performance can be obtained.

As the copolymerizable monomer, a monomer having a polar group can be used appropriately. The monomer having a polar group is useful for introducing a crosslinking point into the acrylic polymer or increasing the cohesive force of the acrylic polymer. The copolymerizable monomer can be used alone or in combination of two or more.

Specific non-limiting examples of copolymerizable monomers include hydroxyl-containing monomers (hydroxyl-containing monomers), carboxyl-containing monomers (carboxyl-containing monomers), sulfonic acid group-containing monomers, phosphate group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, monomers having a nitrogen atom-containing ring, monomers having a succinimide skeleton, maleimides, itaconicimides, (meth)acrylic acid aminoalkyl esters, (meth)acrylic acid alkoxyalkyl esters, vinyl esters, vinyl ethers, aromatic vinyl compounds, olefins, and the like.

A hydroxyl-containing monomer refers to a monomer having at least one hydroxyl group in the molecule. When the monomer component used to constitute the acrylic polymer includes a hydroxyl-containing monomer, that is, when the acrylic polymer includes a monomer unit derived from the hydroxyl-containing monomer, it is easy to obtain adhesion and appropriate cohesion in the first adhesive layer. In addition, when the acrylic polymer includes a monomer unit derived from the hydroxyl-containing monomer and the first adhesive layer includes a crosslinking agent (curing agent) such as an isocyanate crosslinking agent, the hydroxyl-containing monomer unit can be crosslinked between itself and the crosslinking agent, so hardness and good bonding reliability can be easily obtained in the first adhesive layer. The acrylic polymer of this embodiment can use one hydroxyl-containing monomer, or can use two or more hydroxyl-containing monomers.

In a preferred embodiment, the hydroxyl-containing monomer preferably includes a hydroxyl-containing monomer having a primary hydroxyl group and/or a hydroxyl-containing monomer having a secondary hydroxyl group.

In a preferred embodiment, the hydroxyl-containing monomer comprises a hydroxyl-containing (meth)acrylate and/or an unsaturated alcohol.

Examples of the (meth)acrylate containing a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, and polycaprolactone acrylate.

Examples of unsaturated alcohols include vinyl alcohol and allyl alcohol.

The content of the hydroxyl-containing monomer is not particularly limited. From the viewpoint of obtaining sufficient adhesion and appropriate cohesion in the first adhesive layer; or when the first adhesive layer contains a crosslinking agent such as an isocyanate crosslinking agent, from the viewpoint of obtaining hardness and good bonding reliability in the adhesive layer, the content of the hydroxyl-containing monomer is 0.1 to 5 parts by weight, preferably 2 to 4 parts by weight, based on 100 parts by weight of all monomer components of the acrylic polymer. When the content of the hydroxyl-containing monomer is less than 0.1 parts by weight, sufficient adhesion cannot be obtained. When the content of the hydroxyl-containing monomer is greater than 5 parts by weight, the first adhesive layer becomes too hard and the bonding reliability is reduced.

A carboxyl group-containing monomer refers to a monomer having at least one carboxyl group in the molecule. By including a carboxyl group-containing monomer in the monomer component, an adhesive sheet with good durability can be easily obtained. In addition, the adhesion between the adhesive layer and the adherend can also be further improved.

As carboxyl-containing monomers, preferably include ethylenic unsaturated monocarboxylic acids and/or ethylenic unsaturated dicarboxylic acids and anhydrides thereof. Examples of ethylenic unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, crotonic acid, and isocrotonic acid. Examples of ethylenic unsaturated dicarboxylic acids and anhydrides thereof include fumaric acid, itaconic acid, maleic acid, citric acid, maleic anhydride, and itaconic anhydride. Among these, acrylic acid, methacrylic acid, and maleic acid are preferred. The above-mentioned carboxyl-containing monomers may be used alone or in combination of two or more.

The content of the carboxyl group-containing monomer is not particularly limited. For example, the content of the carboxyl group-containing monomer is preferably 1 to 5 parts by weight, and more preferably 2 to 4 parts by weight, relative to 100 parts by weight of all monomer components of the acrylic polymer. By setting the content of the carboxyl group-containing monomer within the above range, the bonding strength can be increased, and an adhesive sheet with excellent bonding performance can be further achieved. When the content of the carboxyl group-containing monomer is less than 1 part by weight, sufficient adhesion cannot be obtained. When the content of the carboxyl group-containing monomer is greater than 5 parts by weight, the bonding reliability is reduced.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid.

Examples of the monomer containing a phosphate group include 2-hydroxyethyl acryloyl phosphate and the like.

Examples of the epoxy group-containing monomer include epoxy group-containing acrylates such as glycidyl (meth)acrylate and 2-ethyl glycidyl (meth)acrylate, allyl glycidyl ether, and glycidyl (meth)acrylate.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the isocyanate group-containing monomer include 2-isocyanatoethyl (meth)acrylate and the like.

Examples of monomers containing an amide group include (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N,N-di(n-butyl) (meth)acrylamide, N,N-di(tert-butyl) (meth)acrylamide; N,N-dialkyl (meth)acrylamide such as N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide; N-alkyl(meth)acrylamide such as amine, N-n-butyl(meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinylacetamide; N,N-dimethylaminopropyl(meth)acrylamide, hydroxyethylacrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-hydroxymethylpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-methoxyethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-(meth)acryloylmorpholine, etc.

Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(methyl)acryloyl-2-pyrrolidone, N-(methyl)acryloylpiperidine, N-(Meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinyloxazine, etc. (for example, lactamides such as N-vinyl-2-caprolactam).

Examples of the monomer having a succinimide skeleton include N-(meth)acryloxymethylenesuccinimide, N-(meth)acryl-6-oxyhexamethylenesuccinimide, and N-(meth)acryl-8-oxyhexamethylenesuccinimide.

Examples of maleimides include N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide.

Examples of itaconimides include N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-lauryl itaconimide.

Examples of the aminoalkyl (meth)acrylates include aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate.

Examples of the alkoxyalkyl (meth)acrylates include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and ethoxypropyl (meth)acrylate.

Examples of the vinyl esters include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the vinyl ethers include vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

As the aromatic vinyl compound, for example, styrene, α-methylstyrene, vinyltoluene, chlorostyrene, chloromethylstyrene and the like can be listed.

Examples of olefins include ethylene, butadiene, isoprene, and isobutylene.

The method for obtaining acrylic polymers is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be appropriately adopted. For example, solution polymerization can be preferably adopted. As a monomer supply method when performing solution polymerization, a batch feeding method in which all monomer raw materials are supplied at one time, a continuous supply (drip) method, a divided supply (drip) method, etc. can be appropriately adopted. The polymerization temperature when performing solution polymerization can be appropriately selected according to the types of monomers and solvents used, the type of polymerization initiator, etc., and can be set to, for example, about 20 to 170°C (typically about 40 to 140°C).

The solvent (polymerization solvent) used in the solution polymerization can be appropriately selected from the existing known organic solvents. For example, any one solvent or a mixed solvent of two or more selected from aromatic compounds such as toluene (typically aromatic hydrocarbons); acetates such as ethyl acetate; aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols such as isopropanol (e.g. monohydric alcohols with 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone, etc. can be used.

The initiator used in the polymerization can be appropriately selected from existing known polymerization initiators according to the type of polymerization method. For example, one or more azo polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN) can be preferably used. Other examples of polymerization initiators include: persulfates such as potassium persulfate; peroxide-type initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane-type initiators such as phenyl-substituted ethane; aromatic carbonyl compounds, etc. As another example of polymerization initiators, redox initiators obtained by combining peroxides and reducing agents can be listed. Such polymerization initiators can be used alone or in combination of two or more. The amount of the polymerization initiator used may be a normal amount, for example, it can be selected from the range of about 0.005 to about 1 part by weight (typically about 0.01 to about 1 part by weight) relative to 100 parts by weight of all monomer components.

By the above-mentioned solution polymerization, a polymerization reaction liquid in the form of an acrylic polymer dissolved in an organic solvent can be obtained. The adhesive layer in the technology disclosed herein can be formed by an adhesive composition containing the above-mentioned polymerization reaction liquid or an acrylic polymer solution obtained by subjecting the reaction liquid to appropriate post-treatment. As the above-mentioned acrylic polymer solution, an acrylic polymer solution in which the above-mentioned polymerization reaction liquid is adjusted to an appropriate viscosity (concentration) as needed can be used. Alternatively, an acrylic polymer solution prepared by synthesizing an acrylic polymer by a polymerization method other than solution polymerization (e.g., emulsion polymerization, photopolymerization, bulk polymerization, etc.) and dissolving the acrylic polymer in an organic solvent can also be used.

The weight average molecular weight (Mw) of the soluble part of the acrylic adhesive in the technology disclosed herein is not particularly limited. From the viewpoint of self-adhesive performance, the Mw of the soluble part of the acrylic adhesive is preferably in the range of 80,000 or less, and more preferably 5,000 or more. When the weight average molecular weight is less than 5,000, the cohesive force of the adhesive layer tends to decrease, and sometimes the adherend is offset when being fixed, or residual adhesive is generated when peeling. On the other hand, when the weight average molecular weight exceeds 80,000, the cohesive force tends to increase due to the effect of polymer entanglement, thereby reducing fluidity, and sometimes a sufficient bonding area cannot be obtained and the adherend cannot be fixed. Here, Mw refers to a value obtained by GPC (gel permeation chromatography) in terms of standard polystyrene. For example, a GPC apparatus of model name "HLC-8320GPC" (column: TSKgelGMH-H(S), manufactured by Tosoh Corporation) can be used.

In the first adhesive layer disclosed herein, a crosslinking agent may be used to adjust the cohesive force, etc. The crosslinking agent may be a commonly used crosslinking agent, for example, epoxy crosslinking agents, isocyanate crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, metal chelate crosslinking agents, etc. These crosslinking agents may be used alone or in combination of two or more.

In a preferred embodiment, the crosslinking agent preferably comprises an epoxy crosslinking agent and/or an isocyanate crosslinking agent. By using these two crosslinking agents, the cohesive force of the adhesive layer can be fully improved. In addition, in the composition comprising the substrate layer, good adhesion to the substrate layer can be guaranteed. The adhesive layer in the technology disclosed here can contain the above-mentioned crosslinking agent in the form after the crosslinking reaction, the form before the crosslinking reaction, the form partially subjected to the crosslinking reaction, the intermediate form or the composite form of these forms. The above-mentioned crosslinking agent is typically contained in the adhesive layer only in the form after the crosslinking reaction.

As the epoxy crosslinking agent, a compound having two or more epoxy groups in one molecule can be used without particular limitation. Preferably, it is an epoxy crosslinking agent having 3 to 5 epoxy groups in one molecule. The epoxy crosslinking agent can be used alone or in combination of two or more.

Specific examples of epoxy crosslinking agents are not particularly limited, and include, for example, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc. Commercially available products of epoxy crosslinking agents include "TETRAD-C" and "TETRAD-X" manufactured by Mitsubishi Gas Chemicals, "EPICLON CR-5L" manufactured by DIC Corporation, "DENACOL EX-512" manufactured by Nagase Chemicals, and "TEPIC-G" manufactured by Nissan Chemical Industries, Ltd.

The amount of the epoxy crosslinking agent used is not particularly limited. The amount of the epoxy crosslinking agent used is preferably set to 0.1 to 2 parts by weight relative to 100 parts by weight of the acrylic polymer.

In the embodiment containing an epoxy-based crosslinking agent, the epoxy equivalent of the epoxy-based crosslinking agent is preferably 80-120 g/eq.

As the isocyanate crosslinking agent, a polyfunctional isocyanate (a compound having an average of two or more isocyanate groups per molecule, including a compound having an isocyanurate structure) can be preferably used. The isocyanate crosslinking agent can be used alone or in combination of two or more.

Examples of the polyfunctional isocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and the like.

Specific examples of aliphatic polyisocyanates include 1,2-ethylene diisocyanate; 1,2-butanediisocyanate, 1,3-butanediisocyanate, 1,4-butanediisocyanate and other succinic diisocyanates; 1,2-hexanediisocyanate, 1,3-hexanediisocyanate, 1,4-hexanediisocyanate, 1,5-hexanediisocyanate, 1,6-hexanediisocyanate, 2,5-hexanediisocyanate and other succinic diisocyanates; 2-methyl-1,5-pentanediisocyanate, 3-methyl-1,5-pentanediisocyanate, lysine diisocyanate and the like.

Specific examples of alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanates such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, and 1,4-cyclohexyl diisocyanate; cyclopentyl diisocyanates such as 1,2-cyclopentyl diisocyanate and 1,3-cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

Specific examples of aromatic polyisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, 2-nitrobiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, isocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate, etc.

Preferred polyfunctional isocyanates include polyfunctional isocyanates having an average of 3 or more isocyanate groups per molecule. The trifunctional or higher-functional isocyanates may be polymers (typically dimers or trimers), derivatives (e.g., addition reaction products of polyols and two or more molecules of polyfunctional isocyanates), polymers, etc. of difunctional or trifunctional or higher-functional isocyanates. For example, polyfunctional isocyanates such as dimers or trimers of diphenylmethane diisocyanate, isocyanurate forms of hexamethylene diisocyanate (trimer adducts of isocyanurate structures), reaction products of trihydroxymethylpropane and toluene diisocyanate, reaction products of trihydroxymethylpropane and hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, polyether polyisocyanate, polyester polyisocyanate, etc. may be cited. Commercially available products of the above-mentioned polyfunctional isocyanate include "DURANATE TPA-100" manufactured by Asahi Kasei Chemicals Co., Ltd., "CORONATE L" manufactured by Nippon Polyurethane Industries Co., Ltd., "CORONATE HL" manufactured by Nippon Polyurethane Industries Co., Ltd., "CORONATE HK" manufactured by Nippon Polyurethane Industries Co., Ltd., "CORONATE HX" manufactured by Nippon Polyurethane Industries Co., Ltd., and "CORONATE 2096" manufactured by Nippon Polyurethane Industries Co., Ltd., etc.

In the embodiment containing an isocyanate crosslinking agent, the isocyanate group content (NCO content) in the isocyanate crosslinking agent is preferably 7-15%.

The amount of the isocyanate crosslinking agent used is not particularly limited. The amount of the isocyanate crosslinking agent used can be set to 1 to 5 parts by weight relative to 100 parts by weight of the acrylic polymer, for example.

As the crosslinking agent, it is preferred to use an isocyanate crosslinking agent and an epoxy crosslinking agent in combination. By using the above amount of the isocyanate crosslinking agent and the above amount of the epoxy crosslinking agent in combination, it is possible to take into account both the adhesion to the adherend and the substrate layer and the cohesion at a high level. Thus, an adhesive sheet showing good retention performance (cohesion of the adhesive layer) can be realized.

Examples of aziridine crosslinking agents include trihydroxymethylpropane tris[3-(1-aziridinyl)propionate] and trihydroxymethylpropane tris[3-(1-(2-methyl)aziridinylpropionate)]. Commercially available products can be used as aziridine crosslinking agents. For example, Chemitite series such as Chemitite PZ-33 and Chemitite DZ-22E (manufactured by Nippon Shokubai Co., Ltd.) can be used.

Examples of melamine-based crosslinking agents include hexylmethylmelamine and butylated melamine resins (for example, "SUPER BECKAMINE J-820-60N" available from DIC Corporation).

Examples of metal chelate crosslinking agents include aluminum chelate compounds, titanium chelate compounds, zinc chelate compounds, zirconium chelate compounds, iron chelate compounds, cobalt chelate compounds, nickel chelate compounds, tin chelate compounds, manganese chelate compounds, and chromium chelate compounds.

The content of the crosslinking agent is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the acrylic polymer. If the content is less than 0.01 parts by weight, the cohesive force of the acrylic adhesive is reduced, and the bonding reliability is poor. On the other hand, if the content exceeds 10 parts by weight, the cohesive force of the acrylic adhesive is large, the fluidity is reduced, and the adhesion strength over time is poorly increased.

In order to more effectively carry out the crosslinking reaction, a crosslinking catalyst may be used. As the crosslinking catalyst, for example, a tin-based catalyst (e.g., dioctyltin dilaurate) may be preferably used. The amount of the crosslinking catalyst used is not particularly limited, and for example, it is preferably 0.0001 to 1 part by weight relative to 100 parts by weight of the acrylic polymer.

In addition to the above-mentioned components, the adhesive layer disclosed herein may contain various additives commonly used in the adhesive field, such as leveling agents, crosslinking aids, plasticizers, softeners, antistatic agents, antioxidants, and antioxidants, as needed. With regard to these various additives, conventionally known additives may be used by known methods.

(Formation of the first adhesive layer) The first adhesive layer disclosed herein can be formed by a conventionally known method. For example, a method (direct method) can be adopted in which an acrylic adhesive (adhesive composition) is directly applied (typically coated) to the substrate layer and dried to form the adhesive layer. In addition, a method (transfer method) can be adopted in which an acrylic adhesive (adhesive composition) is applied to a releasable surface (release surface) and dried to form an adhesive layer on the surface, and the adhesive layer is transferred to the substrate layer. From the perspective of productivity, the transfer method is preferred. As the above-mentioned release surface, the surface of the release pad, the back of the base layer subjected to release treatment, etc. can be used. It should be noted that the adhesive layer disclosed herein is typically formed continuously, but is not limited to this form, and can also be formed into a regular or irregular pattern such as dots or stripes.

The adhesive composition can be applied using a conventionally known coating machine such as a gravure roll coater, a die coater, or a rod coater. Alternatively, the adhesive composition can be applied by dipping or curtain coating.

From the perspective of promoting crosslinking reaction and improving manufacturing efficiency, the drying of the adhesive composition is preferably performed under heating. The drying temperature can be set to about 40-150°C, and is usually preferably set to about 60-130°C. After the adhesive composition is dried, aging can be further performed for the purpose of regulating the migration of components in the adhesive layer, the progress of crosslinking reaction, and the relaxation of strain that may exist in the base film or the adhesive layer.

The thickness of the first adhesive layer is not particularly limited, but is preferably 5 to 50 μm, and more preferably 15 to 40 μm. By setting the thickness of the first adhesive layer to the above range, good adhesion can be achieved. When the thickness of the first adhesive layer is less than 5 μm, the adhesive strength may not increase well over time. On the other hand, when the thickness of the first adhesive layer exceeds 50 μm, the adhesive strength suppression effect after bonding may be insufficient.

(Characteristics of the first adhesive layer) The ratio of the 180° peeling adhesion N2 of the first adhesive layer relative to the stainless steel plate after heating at 100~150℃, preferably 130℃ for 3~10 minutes to the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate at 20~25℃, preferably 23℃, is N2/N1≤2, preferably N2/N1≤1.5. By setting the above-mentioned N2/N1 within the above-mentioned range, the pressure-sensitive adhesive sheet of the present invention does not have the disadvantage that the chip is not supported by the above-mentioned pressure-sensitive adhesive sheet and deviates from the specified position due to the pressure during the resin encapsulation, and the pressure-sensitive adhesive sheet can be peeled off without damaging the package body, and no residual adhesive occurs to the encapsulating resin after encapsulation. When N2/N1 exceeds 2, due to the curing and heat of the encapsulating resin, the pressure-sensitive adhesive sheet becomes strongly bonded to the chip surface or the encapsulating resin surface, thereby causing damage to the package body when the above-mentioned adhesive sheet is peeled off. The 180° peeling adhesion test is measured according to the method and conditions described in the embodiment described later.

The first adhesive layer in the present invention preferably has a 180° peeling adhesive force N1 relative to a stainless steel plate at 20-25°C, preferably 23°C, of 0.1-3.0N/20mm, more preferably 0.4-2.0N/20mm. By making the 180° peeling adhesive force N1 of the first adhesive layer relative to a stainless steel plate at 20-25°C, preferably 23°C within the above range, the adhesive sheet has sufficient adhesive force. When the above 180° peeling adhesive force N1 is less than 0.1N/20mm, the adhesion to the chip becomes insufficient, and the pressure during peeling during operation and during resin encapsulation causes the chip position to shift. When the 180° peeling adhesive force N1 exceeds 3.0N/20mm, the adhesive layer is difficult to peel off from the chip, the peeling operation is poor, and the package is damaged during the peeling process.

The first adhesive layer of the present invention preferably has a 180° peeling adhesion N2 relative to a stainless steel plate after heating at 100-150°C, preferably 130°C for 3-10 minutes of 0.2-6.0N/20mm, more preferably 0.5-3.0N/20mm. By having the 180° peeling adhesion N2 within the above range after heating at 100-150°C, preferably 130°C for 3-10 minutes, the pressure-sensitive adhesive sheet of the present invention has excellent adhesive reliability after being attached to an adherend, and the pressure-sensitive adhesive sheet can be peeled without damaging the package body, and no residual adhesive will occur to the encapsulating resin after encapsulation.

When the 180° peeling adhesive force N2 is less than 0.2N/20mm, the adhesion to the chip is insufficient, and the pressure during peeling and resin encapsulation during operation causes the chip position to shift. When the 180° peeling adhesive force N2 exceeds 6.0N/20mm, the pressure-sensitive adhesive tape is strongly bonded to the chip surface due to the curing and heating of the encapsulating resin, resulting in damage to the package body when the tape is peeled off, and residual adhesive to the encapsulating resin after encapsulation.

The gel rate of the first adhesive layer is preferably greater than 70%, more preferably greater than 80%. When the gel rate of the first adhesive layer is within the above range, excellent bonding properties can be obtained, the wafer does not shift when encapsulated with the resin, and no residual resin occurs for the encapsulating resin. The gel rate of the first adhesive layer can be adjusted, for example, according to the composition and molecular weight of the acrylic polymer, the presence or absence of the crosslinking agent, the type of the crosslinking agent, and the amount of the crosslinking agent.

The gelation rate of the adhesive layer is calculated as follows. First, collect a sample from the adhesive layer, measure the weight of the sample, and refer to this weight as "W1". Then, wrap the sample in a purse shape with a porous membrane made of tetrafluoroethylene resin, tie its mouth with a kite line, and obtain a package. Then, immerse the package in ethyl acetate and leave it at room temperature (typically 23°C) for 7 days. Then, recover the package from ethyl acetate and dry the recovered package at 130°C for 2 hours. After drying, measure the weight of the package, and subtract the weight of the porous membrane made of tetrafluoroethylene resin and the weight of the kite line from the weight of the package to obtain the weight of the sample, and refer to this weight as "W2". Then, calculate the gelation rate by the following formula. Gel rate (mass %) = (W2)/(W1)×100

The first adhesive layer has a storage modulus G' of 0.5×10 ⁵ ~12×10 ⁵ Pa, preferably 2×10 ⁵ ~9×10 ⁵ Pa at 20~25°C, preferably 23°C. When the storage modulus G' of the first adhesive layer at 20~25°C, preferably 23°C, is within the above range, the chip embedding into the adhesive layer due to the pressure when the chip is bonded to the pressure-sensitive adhesive sheet and when the chip is encapsulated with the resin can be reduced, and the position difference (deviation) associated with the embedded chip surface protruding relative to the encapsulating resin surface can be reduced. In the present invention, the storage modulus G' can be measured by a dynamic mechanical analyzer (DMA).

The energy storage modulus G' of the first adhesive layer can be controlled, for example, by the type of resin constituting the adhesive in the first adhesive layer (i.e., the glass transition temperature, molecular weight, etc. of the resin). The glass transition temperature of the resin constituting the adhesive in the first adhesive layer can be adjusted, for example, by appropriately selecting the monomer constituting the resin.

<Second Adhesive Layer> In a preferred embodiment, as shown in FIG. 7 , the heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices of the present invention also includes a second adhesive layer 13, which is disposed on a side of the substrate layer opposite to the first adhesive layer.

Examples of the adhesive constituting the second adhesive layer include silicone adhesives, acrylic adhesives including acrylic polymers as base polymers, rubber adhesives including natural rubber or synthetic rubber as base polymers, styrene/copolymer diene block copolymer adhesives, polyester adhesives, polyamide adhesives, etc. Among them, silicone adhesives and acrylic adhesives are preferably used, and silicone adhesives are more preferably used from the viewpoint of heat resistance.

As the above-mentioned organic silicone adhesive, an organic silicone adhesive using, for example, an organic silicone rubber or an organic silicone resin containing an organic polysiloxane as a base polymer is preferably used. As the base polymer constituting the organic silicone adhesive, a base polymer obtained by cross-linking the above-mentioned organic silicone rubber or organic silicone resin can also be used.

As the acrylic adhesive, any appropriate acrylic adhesive can be used. For example, an acrylic adhesive using an acrylic polymer (homopolymer or copolymer) as a base polymer can be cited, and the acrylic polymer uses one or more (meth) alkyl acrylates as monomer components. In one embodiment, the acrylic adhesive described in the first adhesive layer can be used, and no detailed description is given here.

Examples of the rubber-based adhesive include rubber-based adhesives using the following rubbers as base polymers: natural rubber; polyisoprene rubber, styrene-butadiene (SB) rubber, styrene-isoprene (SI) rubber, styrene-isoprene-styrene block copolymer (SIS) rubber, styrene-butadiene-styrene block copolymer (SBS) rubber, styrene-ethylene-butylene-styrene block copolymer (SEBS) rubber, styrene-ethylene-propylene-styrene block copolymer (SEPS) rubber, styrene-ethylene-propylene block copolymer (SEP) rubber, recycled rubber, butyl rubber, polyisobutylene, synthetic rubbers such as modified products thereof, and the like.

The second adhesive layer and the first adhesive layer may have the same composition and structure, or one or both of the composition and structure may be different. As an example of the second adhesive layer and the first adhesive layer having the same composition and different structure, the first adhesive layer and the second adhesive layer are adhesive layers of different thicknesses composed of an adhesive composition of the same composition.

For the adhesive used in the second adhesive layer, the weight average molecular weight (Mw) of the soluble part of the adhesive is preferably 2,000 to 6,000. When the weight average molecular weight is less than 2,000, the cohesive force of the adhesive layer tends to decrease, and sometimes the adherend is offset when fixed, or residual glue is generated when peeled off. On the other hand, when the weight average molecular weight exceeds 6,000, the cohesive force increases due to the effect of polymer entanglement, thereby reducing fluidity, and sometimes a sufficient bonding area cannot be obtained and the adherend cannot be fixed.

In the second adhesive layer, the gelation rate is preferably 40-90%, preferably 50-85%, from the perspective of balancing the self-adhesive properties (adhesive strength, viscosity, durability, and retention properties). When it is less than 40%, insufficient cohesion may occur, resulting in cohesive failure during peeling, and part of the adhesive may remain on the surface of the adherend, resulting in reduced processability. On the other hand, when it exceeds 90%, insufficient viscosity may occur, and the bonding requirements may not be met, resulting in reduced bonding reliability. The gelation rate of the second adhesive layer can be adjusted, for example, based on the composition and molecular weight of the adhesive, the presence or absence of the use of a crosslinking agent, its type, and the selection of the amount of the crosslinking agent.

The second adhesive layer has a 15° peeling adhesive force of 2 to 100 N/20 mm, preferably 2 to 50 N/20 mm, relative to a stainless steel plate at 20 to 25°C, preferably 23°C. By setting the 15° peeling adhesive force to such a range, the pressure-sensitive adhesive sheet can have sufficient adhesive force and can be easily peeled off after use. When the 15° peeling adhesive force is less than 2 N/20 mm, it may be easily peeled off outside the peeling process. On the other hand, when the above-mentioned 15° peeling adhesive force exceeds 100N/20mm, the peeling workability may be poor when it is not necessary, and the adherend may be damaged due to the peeling work.

The second adhesive layer has a 15° peeling adhesion to a stainless steel plate of 3~130N/20mm, preferably 3~100N/20mm, after being heated at 150°C for 4 hours. By setting the above 15° peeling adhesion to such a range, the pressure-sensitive adhesive sheet has excellent adhesive reliability over time when adhered to the adherend, and can be easily peeled off after use. When the above 15° peeling adhesion is less than 3N/20mm, the adhesion to the adherend is insufficient. On the other hand, when the above 15° peeling adhesion exceeds 130N/20mm, the peeling workability is poor, resulting in damage to the adherend or residual adhesive contamination.

The second adhesive layer has a storage modulus G' of 0.8×10 ⁵ ~2.5×10 ⁵ Pa, preferably 1×10 ⁵ ~2.5×10 ⁵ Pa at 20~25°C, preferably 23°C. By setting the storage modulus G' at 23°C within the above range, the second adhesive layer can maintain the cohesive force required for processability or handling, and can ensure the initial adhesion when the second adhesive layer is attached to the adherend.

The energy storage modulus G' of the second adhesive layer at 150°C is 0.5×10 ⁵ ~1.6×10 ⁵ Pa. By setting the energy storage modulus G' at 150°C within the above range, an adhesive sheet having an excellent balance between adhesive strength and releasability can be obtained.

The energy storage modulus G' of the second adhesive layer can be controlled, for example, by the type of resin constituting the adhesive in the second adhesive layer (i.e., the glass transition temperature, molecular weight, etc. of the resin). The glass transition temperature of the resin constituting the adhesive in the second adhesive layer can be adjusted, for example, by appropriately selecting the monomer constituting the resin. In the present invention, the energy storage modulus G' can be measured by a dynamic mechanical analyzer (DMA).

The thickness of the second adhesive layer is not particularly limited, but is preferably 5 to 50 μm, and more preferably 10 to 40 μm. By setting the thickness of the second adhesive layer to the above range, good adhesion can be achieved. When the thickness of the second adhesive layer is less than 5 μm, the adhesive strength may not increase well over time. On the other hand, when the thickness of the second adhesive layer exceeds 50 μm, the adhesive strength suppression effect after bonding may be insufficient.

(Release film) The heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices of the present invention may further have a release film as needed. The release film is a sheet including a base film and a release agent layer formed on one side thereof, and is a sheet that is peeled off in order to expose each surface of the adhesive layer before using the heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices of the present invention. In the present invention, as shown in FIG. 7 , the heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices includes a first release film 10 and a second release film 14. The first release film 10 is disposed on a side of the first adhesive layer 12 opposite to the substrate layer 11 , and the second release film 14 is disposed on a side of the second adhesive layer 13 opposite to the substrate layer 11 .

The release agent layer can be obtained by appropriately selecting from known release agents such as long-chain alkyl resins, fluororesins and silicone resins according to the adhesive to be in contact with it.

As the substrate film, a known film can be used, and can be selected from, for example, plastic films such as polyetheretherketone, polyetherimide, polyarylate, polyethylene naphthalate, polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, polyvinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, ionic bond resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film and polycarbonate film.

Depending on the resin of the adhesive layer, the stripping agent layer that can be used is a layer containing a stripping agent selected from known stripping agents such as fluorinated polysilicone resin stripping agents, fluorine resin stripping agents, polysilicone resin stripping agents, polyvinyl alcohol resins, polypropylene resins, and long-chain alkyl compounds.

<Production method of heat-resistant pressure-sensitive adhesive sheet for semiconductor device production> The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can be produced by a general production method. For example, a composition for constituting a first adhesive layer and, if necessary, a second adhesive layer is dissolved in a given solvent to prepare a coating liquid, the coating liquid is applied to a substrate layer to obtain a target layer structure of a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, and then the obtained coating layer is heated and dried under given conditions.

In addition, a single film can be prepared by, for example, casting each solution of the composition for constituting the first adhesive layer, the second adhesive layer, etc. on a peelable film, etc., and those films can be laminated on the substrate layer in sequence. The application of the coating liquid and the lamination by the single film can be combined. The solvent used is not particularly limited. Considering the need for good solubility of the material used to constitute the adhesive layer, a ketone solvent such as methyl ethyl ketone is preferably used. The following method of forming a pressure-sensitive adhesive sheet for producing semiconductor devices can also be used: preparing a constituent material of an adhesive layer into an aqueous dispersion solution, applying the solution to a base layer, heating and drying the resulting coated layer, and repeating these steps to laminate the adhesive layer.

<Method of using heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices> The heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices is used in the steps shown in FIG. 1 and FIGS. 2A to 2F, etc.

As an example, an outline of a method for producing a substrate-less BGA is described below.

FIG. 1 is a diagram showing a method for producing a semiconductor device in which a substrate-less semiconductor wafer is encapsulated with a resin, the method employing the heat-resistant pressure-sensitive adhesive sheet for producing a semiconductor device of the present invention.

In step (a), the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention is bonded and fixed to a substrate 3. In step (b), semiconductor chips are bonded and fixed to the sheet at arbitrary intervals. In the subsequent step (c), the fixed semiconductor chips are encapsulated with an encapsulating resin 4 to embed the chips.

In step (d), the plurality of chips thus encapsulated are peeled off from the substrate together with the encapsulating resin and the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices by thermal peeling. In step (e), the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices of the present invention is peeled off from the semiconductor chips encapsulated by the resin.

In step (f), various patterns are printed and applied to the area between the semiconductor chip and the surface of the semiconductor chip to form wiring leads, etc. In the subsequent step (g), the wiring leads are formed into bumps, etc., which are ball-shaped connection electrodes on the surface of the chip.

Finally, in step (h), the encapsulating resin portion between the semiconductor chips is cut by dicing or the like, thereby obtaining each semiconductor device mounted with an individual semiconductor chip.

The following specifically describes the production method of the substrate-less package with reference to FIGS. 2A to 2F.

(Semiconductor chip bonding step) The heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production is fixed to the substrate 3 by bonding or the like, and the first adhesive layer side is exposed on the substrate.

A given semiconductor chip 1 to be encapsulated with resin is placed on and bonded to the first adhesive layer so as to obtain a given structure, thereby fixing the chip 1 to the first adhesive layer of the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production, as shown in Fig. 2A. In this case, the structure, shape, size, etc. of the semiconductor chip are not particularly limited.

As the case may be, a plurality of wafers 1 are bonded to a heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices having adhesive layers on both sides thereof, and the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices is fixed to a substrate 3 to form a structure as shown in FIG. 2A .

(Encapsulation step) The chip 1 having the structure shown in FIG2A is encapsulated with an encapsulation resin 4 so as to integrate multiple chips 1 to form the structure shown in FIG2B.

The resin used in the encapsulation step in which the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention is used can be a known encapsulation resin such as an epoxy resin. The melting temperature and the curing temperature of the powdered resin and the curing temperature of the liquid resin are selected in consideration of the heat resistance of the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production. The heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention has heat resistance at the melting temperature and the curing temperature of the ordinary encapsulation resin.

For the purpose of protecting the wafer, the encapsulation step is performed in a mold using the above-mentioned resin and is performed at a temperature of, for example, 170 to 180°C.

After the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production is peeled off, post-molding curing is performed.

(Peeling step) After the chip 1 of the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production fixed on the substrate 3 is encapsulated with resin, it is heated under the following conditions: at a temperature of 200 to 250°C for a time of 1 to 90 seconds (hot plate, etc.) or a time of 1 to 15 minutes (hot air dryer) to release the fixation between the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production and the substrate 3 by the pressure-sensitive adhesive, etc., and the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production and the substrate 3 are separated from each other.

Thereafter, the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production is peeled off from the layer including the wafer 1 encapsulated with the resin, as shown in FIG. 2C.

As the case may be, the following method may be used: in which the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices and the substrate 3 are not separated from each other and remain in an integrated form, and the plurality of chips 1 encapsulated with the encapsulating resin are separated from the pressure-sensitive adhesive layer of the heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices.

(Electrode formation step) As shown in FIG. 2D, on one side of a layer including a wafer 1 encapsulated with a resin, a heat-resistant pressure-sensitive adhesive sheet 2 for producing semiconductor devices is pressed on the upper layer, and a portion of the surface of the wafer 1 is exposed, and an electrode 5 is formed on a given area of each wafer by a method such as screen printing. The electrode material used can be a known material.

(Cutting step) As shown in FIG. 2E, the layer including the wafer 1 encapsulated with resin is fixed to a dicing tape 8 preferably having a dicing ring 7, and dicing is performed using a dicing knife 6 used in a normal dicing step, thereby obtaining a plurality of substrate-free packages each having a plurality of wafers 1 encapsulated with resin as shown in FIG. 2F.

In this case, when each chip 1 is not positioned at a given position, the formation of the electrode 5 becomes inaccurate, and the position of the chip 1 in each package becomes inaccurate. In the worst case, there is a possibility that the dicing blade 6 contacts the chip 1 when dicing.

When the heat-resistant pressure-sensitive adhesive sheet 2 for semiconductor device production of the present invention is used, the positional deviation of the chip 1 can be prevented in the encapsulation step with the resin. Therefore, the dicing step can be smoothly performed without such a problem, and as a result, a package body in which the chip 1 is accurately positioned in the encapsulation resin 4 can be obtained.

In addition, in the conventional method, there is also a case where the chip is not supported by the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production due to the pressure of the encapsulating resin and deviates from the specified position, or the chip is embedded in the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production due to the pressure of the encapsulating resin being too strong, or the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production being too soft, or due to a combination of these reasons, as shown in FIG3B. In such a case, there is a concern that the chip cannot be completely encapsulated with the encapsulating resin, and the chip protrudes from the resin surface to form a state (deviation) in which a position difference occurs between the encapsulating resin surface and the chip surface.

When a portion of the chip protrudes from the resin surface, a deviation occurs in the height of the surface of the electrode to be formed later. Therefore, when the chip is connected to the circuit board, it becomes difficult to connect the chip to the circuit board with certainty.

When the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention is used, the chip is not embedded in the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, as shown in FIG3A, the chip does not protrude from the cured encapsulation resin surface, and the subsequent formation of electrodes between the chips is also performed with certainty. In addition, even in the case where the package body is set on the circuit substrate, each electrode can be connected to a predetermined area on the circuit substrate with certainty.

In addition, during the conventional encapsulation with resin, due to the expansion and elasticity of the base material layer and the adhesive layer of the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production shown in FIG. 4 (a) is deformed in the plane direction shown in FIG. 4 (b), so that the position of the chip placed on the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production may move in some cases. In addition, the chip may sometimes move due to the pressure caused when the resin used for encapsulation is packaged.

As a result, when the electrodes are placed on the wafer, the relative positional relationship between the wafer and the electrodes is different from the predetermined positional relationship. In addition, when the wafer is encapsulated with resin and then cut, the cutting line determined in advance based on the predetermined position of the wafer in the cutting step is different from the cutting line required by the actual position of the wafer.

In this case, each package obtained by cutting is offset in the position of the encapsulated chip, and the subsequent steps cannot be performed smoothly. In addition, an insufficiently encapsulated package may be unexpectedly obtained.

When peeling off the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production from a wafer encapsulated with a resin, the properties of the pressure-sensitive adhesive formed on the wafer side of the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production are particularly determined. Due to the curing and heating of the encapsulating resin, the adhesive force becomes stronger, thereby showing heavy peeling properties. Therefore, there is a concern that peeling becomes difficult, residual adhesive as shown in Figure 5 occurs, or peeling electrification occurs.

In the case where stripping becomes difficult, the stripping time is prolonged, resulting in deterioration of productivity. In the case where the residual glue 9 shown in FIG. 5 occurs, the subsequent steps such as electrode formation cannot be performed. In addition, in the case where stripping discharge occurs, adverse conditions may occur in the subsequent steps due to the adhesion of dust, etc.

However, when the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention is used, the dicing step can be smoothly performed without the above-mentioned problem, and a package body in which the chip is accurately positioned in the encapsulation resin can be obtained. In addition, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can be easily peeled off after use, and no adhesive residue will occur to the encapsulation resin after encapsulation.

The present invention is described in more detail with reference to the embodiments, but it should be noted that the present invention is not construed as being limited to the embodiments.

Examples <Preparation of adhesive composition> (Example 1) Into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube and a reflux condenser, 94 parts by weight of n-butyl acrylate (BA) (manufactured by Zhejiang Satellite), 1 part by weight of acrylic acid (AA), 5 parts by weight of 2-hydroxyethyl acrylate (HEA) (manufactured by Osaka Organic), and 60 parts by weight of ethyl acetate as a polymerization solvent were added, and stirred at 60-65°C in a nitrogen atmosphere for 1 hour, and then 0.15 parts of 2,2'-azobisisobutyronitrile (AIBN) was added as a thermal polymerization initiator, and the reaction was carried out at 60-65°C for 6 hours to obtain a solution of acrylic polymer A1. The Mw of the acrylic polymer A1 is 640,000.

To the acrylic polymer solution, 5 parts by weight of an isocyanate crosslinking agent (L 75 (C), manufactured by Covestro) and 2 parts by weight of an epoxy crosslinking agent (T/C, manufactured by CVC, USA) were added as crosslinking agents based on 100 parts by weight of the acrylic polymer contained in the solution, and the mixture was stirred and mixed to prepare an adhesive composition C1.

(Examples 2 to 10) In the preparation of the adhesive composition of Example 1, the types and amounts of monomer components and crosslinking agents were set as shown in Table 1, and the other contents were carried out in the same manner as in Example 1 to prepare adhesive compositions C2 to C10 of Examples 2 to 10, respectively.

(Examples 11-14) In the preparation of the adhesive composition of Example 1, the types and amounts of monomer components and crosslinking agents were set as shown in Table 2, and the other contents were carried out in the same manner as in Example 1 to prepare adhesive compositions D1-D4 of Examples 11-14, respectively.

<Preparation of heat-resistant pressure-sensitive adhesive sheet for semiconductor device production> (Example 1) The adhesive composition C1 is applied to one side of a PET film (trade name: biaxially oriented polyester film, manufactured by Nanjing Yabolian New Materials Technology Co., Ltd.) with a thickness of 75 μm as a base layer, and then dried to form a first adhesive layer with a thickness of 25 μm.

Then, 55 parts by weight of polydimethylsiloxane "107 Silicone Rubber" (manufactured by Shenzhen Jipeng Silicone Fluoride Material Co., Ltd.), 45 parts by weight of vinyl MQ resin "VSP8201-4" (manufactured by Chengdu Boda Aifu Technology Co., Ltd.), 1.5 parts by weight of crosslinking agent "91A" (manufactured by Jiangxi Bluestar Spark Organic Silicon Co., Ltd.) and 2 parts by weight of platinum catalyst "CATA 12070" (manufactured by Jiangxi Bluestar Spark Organic Silicon Co., Ltd.) were added to toluene and uniformly dispersed in toluene, and the resulting dispersion was applied to the other side of the substrate layer, followed by drying to prepare a second adhesive layer. Thus, a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production was obtained. The evaluation results are shown in Table 3.

The 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate (SUS430BA plate) at 23°C is 0.11N/20mm.

After heating at 130℃ for 5 minutes, the 180° peeling adhesion N2 of the first adhesive layer relative to the stainless steel plate (SUS430BA plate) is 0.13N/20mm.

The ratio of the 180° peeling adhesion N2 of the first adhesive layer relative to the stainless steel plate (SUS430BA plate) after heating at 130°C for 5 minutes to the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate (SUS430BA plate) at 23°C, i.e., N2/N1, is 1.18.

(Examples 2 to 10) Except that the adhesive composition C2 to C10 in Table 1 was used instead of the adhesive composition C1 to form the first adhesive layer, a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production was obtained in the same manner as in Example 1. The evaluation results are shown in Table 3.

(Comparative Examples 1-4) Except that the adhesive compositions D1-D4 in Table 2 were used instead of the adhesive composition C1 to form the first adhesive layer, a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production was obtained in the same manner as in Example 1. The evaluation results are shown in Table 4.

<Evaluation test> (1) 180° peel adhesion test The pressure-sensitive adhesive sheets of each embodiment and each comparative example were cut into pieces with a width of 20 mm and a length of 150 mm as test pieces. A SUS plate (SUS430BA plate) cleaned with toluene was used as the adherend, and the adhesion N1 and adhesion N2 were measured by the following steps.

(Measurement of Adhesive Force N1) Under a standard environment of 23°C and 50% RH, the peeling pad covering the adhesive surface of each test piece was peeled off, and a 2kg roller was moved back and forth once to press the exposed adhesive surface to the adherend. After the test piece pressed to the adherend in this way was placed in the above standard environment for 30 minutes, it was peeled using a tensile tester (manufactured by Shimadzu Corporation, product name "Tensilon") according to JIS Z 0237 at a tensile speed of 300mm/min and a peeling angle of 180°, and the force required for the peeling (180° peeling adhesive force) (N/20mm) was measured. The measurement results are shown in Tables 3 and 4.

(Measurement of Adhesion Strength N2) The test piece pressed onto the adherend in the same manner as the measurement of adhesion strength N1 was heated at 130°C for 5 minutes, and then placed in the above standard environment for 30 minutes, and the 180° peel adhesion strength was measured in the same manner. The measurement results are shown in Tables 3 and 4.

(2) 15° peel adhesion test The pressure-sensitive adhesive sheets of the examples and comparative examples were cut into test pieces with a width of 20 mm and a length of 150 mm. A SUS plate (SUS430BA plate) cleaned with toluene was used as the adherend, and the adhesion was measured by the following steps.

In a standard environment of 23°C and 50% RH, the peeling pad covering the adhesive surface of each test piece was peeled off, and a 2kg roller was moved back and forth once to press the exposed adhesive surface to the adherend. After the test piece pressed to the adherend in this way was placed in the above standard environment for 30 minutes, it was peeled using a tensile tester (manufactured by Shimadzu Corporation, trade name: "Tensilon") at a tensile speed of 300mm/min and a peeling angle of 15°, and the force required for the peeling (15° peeling adhesion) (N/20mm) was measured. The measurement results are shown in Tables 3 and 4.

The test piece pressed onto the adherend in the same manner as the above-mentioned peel adhesion at 23°C was heated at 150°C for 4 hours, and then placed in the above-mentioned standard environment for 30 minutes, and then the 15° peel adhesion was measured in the same manner. The test results are shown in Tables 3 and 4.

(3) Determination of energy storage modulus The adhesive layer was punched into a diameter of 7.9 mm and fixed by clamping it with parallel plates. The sample obtained was used as the test specimen. For the above test specimen, a dynamic viscoelasticity measurement device (manufactured by Rheometric, product name "ARES") was used to perform dynamic viscoelasticity measurement under the following conditions to measure the energy storage modulus G' at 23°C and the energy storage modulus G' at 150°C. The measurement results of the energy storage modulus of the adhesive layer are shown in Tables 3 and 4. Energy storage modulus measurement conditions Measurement mode: shear mode Temperature range: -70°C~150°C Heating rate: 5°C/min Measurement frequency: 1Hz

(4) Encapsulation The surface of the semiconductor device with the electrode side was neatly attached to the first adhesive layer of the pressure-sensitive adhesive sheet of the above-mentioned embodiment and comparative example, and placed in a vacuum press (manufactured by TOWA Co., Ltd.). Liquid encapsulation resin was injected into the mold cavity of the mold. After heating at 1MPa pressure and 130℃ for 5 minutes, the adhesive sheet was removed and a microscope (manufactured by KEYENCE CORPORATION, trade name: VHX-100, magnification: 200 times) was used to observe whether the liquid encapsulation resin had penetrated into the electrode surface of the semiconductor device, and evaluation was performed according to the following criteria. ○: The amount of liquid encapsulation resin that penetrates into the semiconductor device electrode is less than 0.1% △: The amount of liquid encapsulation resin that penetrates into the semiconductor device electrode is 0.1%~1% ×: The amount of liquid encapsulation resin that penetrates into the semiconductor device electrode is greater than 1%

(5) Adhesive residue The surface of the chip with the electrode was bonded to the first adhesive layer of the pressure-sensitive adhesive sheet of the above-mentioned embodiment and comparative example, and heated in an oven at 150°C for 4 hours. The chip was then peeled off the adhesive sheet, and the bonding surface of the chip was observed with a microscope (manufactured by KEYENCE CORPORATION, trade name: VHX-100, magnification: 200 times) to visually confirm whether there was adhesive residue on the chip electrode, and evaluate according to the following criteria. ○: No adhesive residue was confirmed ×: Adhesive residue was confirmed

(6) Evaluation of the fixity of the first adhesive layer The second adhesive layer of the pressure-sensitive adhesive sheet of the above-mentioned embodiment and comparative example was bonded to a SUS:304 stainless steel substrate, and multiple chips were bonded neatly on the first adhesive layer of the pressure-sensitive adhesive sheet with the surface having the electrode side. After being sealed together with a sealing resin in the mold cavity, a two-dimensional measuring instrument (model: "YVM-3020VT", manufactured by Guangdong Yuanxing Hengzhun Precision Instrument Co., Ltd.) was used to observe whether the relative position of the chip on the first adhesive layer changed. If the position change exceeded 0.005mm, it was considered that the position was offset and evaluated according to the following criteria. ○: The amount of chip position shift on the first adhesive layer is less than 0.1% △: The amount of chip position shift on the first adhesive layer is 0.1%~1% ×: The amount of chip position shift on the first adhesive layer is greater than 1%

(7) Evaluation of fixation of the second adhesive layer The second adhesive layer of the pressure-sensitive adhesive sheet of the above-mentioned embodiment and comparative example was bonded to a SUS:304 stainless steel substrate, and the surfaces of multiple chips with electrodes were neatly bonded to the first adhesive layer of the pressure-sensitive adhesive sheet. After sealing with a sealing resin in the mold cavity, the molded resin was heated at 150°C for 4 hours, and then cut into corresponding sizes. The adhesive sheet was visually observed to see if there was any poor adhesion such as position slippage, edge warping or falling off on the stainless steel substrate, and the evaluation was performed according to the following criteria. ○: No slippage, edge warping or peeling, etc. ×: Slippage, edge warping or peeling, etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc., etc.,

(8) Evaluation of the peelability of the first adhesive layer The surfaces of multiple chips with electrodes on one side were neatly attached to the first adhesive layer of a heat-resistant pressure-sensitive adhesive sheet. After heating at 150°C for 4 hours, a PVC single-sided tape (trade name: SPV-224, manufactured by Nitto Denko Corporation) was attached to the other side of the chip. The heat-resistant pressure-sensitive adhesive sheet was then peeled off at 180° to observe whether the chip was transferred from the first adhesive layer to the PVC single-sided tape. Evaluation was performed according to the following criteria. ○: The amount of chips remaining in the first adhesive layer is less than 0.1% △: The amount of chips remaining in the first adhesive layer is 0.1~1% ×: The amount of chips remaining in the first adhesive layer is greater than 1%

(9) Evaluation of the peelability of the second adhesive layer The second adhesive layer of the heat-resistant pressure-sensitive adhesive sheet was adhered to a SUS:304 stainless steel substrate and heated at 150°C for 4 hours. The heat-resistant pressure-sensitive adhesive sheet was then peeled off at 15°. The second adhesive layer on the peelable side was confirmed to be easily peeled off from the stainless steel substrate by subjective feel. Evaluation was performed according to the following criteria. ○: Very easy to peel △: Relatively easy to peel ×: Not easy to peel off

(10) Comprehensive evaluation Based on the above evaluation results, a comprehensive evaluation is conducted according to the following standards. ○: Excellent comprehensive effect △: Good comprehensive effect ×: Poor comprehensive effect

Table 1 Adhesive composition C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 Base polymer Alkyl (meth)acrylate n-Butyl acrylate (BA) 94 91 94 50 50 50 0 0 94.9 96 2-Ethylhexyl acrylate (2EHA) 0 0 0 46.5 44 46 96 96 0 0 Carboxyl-containing monomers Acrylic acid (AA) 1 5 3 0 0 0 1 0 5 3.6 Methacrylic acid (MAA) 0 0 0 3 3 1 1 2 0 0 Hydroxyl-containing monomers 2-Hydroxyethyl acrylate (HEA) 5 4 3 0 0 0 0 0 0 0 4-Hydroxybutyl acrylate (4-HBA) 0 0 0 0.5 3 3 0 0 0 0 3-Hydroxypropyl acrylate (3-HPA) 0 0 0 0 0 0 2 0 0.1 0 Caprolactone acrylate 0 0 0 0 0 0 0 2 0 0.4 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Crosslinking agent Epoxy crosslinking agent 2.0 1.0 1.0 1.0 1.0 2.0 1.0 0.5 0.5 0.5 Isocyanate crosslinking agent 5.0 3.0 1.0 2.0 1.0 2.0 2.0 2.0 2.0 1.0 Gel rate (%) 98 96 95 95 95 90 85 75 69 62 Weight average molecular weight of soluble fraction (×10 ⁴ ) 0.5 0.8 0.8 0.8 0.9 1.6 3.7 4.6 6.4 7.8

Table 2 Adhesive composition D1 D2 D3 D4 Base polymer Alkyl (meth)acrylate n-Butyl acrylate (BA) 92 90 44 99 2-Ethylhexyl acrylate (2EHA) 0 0 38 0 Methyl Methacrylate (MMA) 0 0 0 0 Carboxyl-containing monomers Acrylic acid (AA) 8 0 6 0 Methacrylic acid (MAA) 0 0 2 0.5 Hydroxyl-containing monomers 2-Hydroxyethyl acrylate (HEA) 0 10 10 0 4-Hydroxybutyl acrylate (4-HBA) 0 0 0 0.5 3-Hydroxypropyl acrylate (3-HPA) 0 0 0 0 Caprolactone acrylate 0 0 0 0 Total 100.0 100.0 100.0 100.0 Crosslinking agent Epoxy crosslinking agent 3.0 0.0 1.0 0.1 Isocyanate crosslinking agent 0.0 6.0 1.0 2.0 Gel rate (%) 99 99 55 32 Weight average molecular weight of soluble fraction (×10 ⁴ ) 0.2 0.3 12 15

Table 3 Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Embodiment 8 Embodiment 9 Embodiment 10 First adhesive layer Adhesive composition C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 180° peeling strength at 23℃ N1 (N/20mm) 0.11 0.20 0.42 0.54 1.13 1.56 1.70 1.90 2.60 2.90 180° peeling adhesion after heating at 130℃ for 5 minutes N2 (N/20mm) 0.13 0.23 0.49 0.65 1.47 2.11 2.42 2.80 4.70 5.70 N2/N1 1.18 1.15 1.17 1.2 1.3 1.35 1.42 1.47 1.81 1.97 Energy storage modulus at 23℃(Pa) 12×10 ⁵ 10×10 ⁵ 9×10 ⁵ 8×10 ⁵ 8×10 ⁵ 7×10 ⁵ 4×10 ⁵ 2×10 ⁵ 1×10 ⁵ 0.5×10 ⁵ Thickness(μm) 25 25 25 25 25 25 25 25 25 25 Encapsulation △ △ ○ ○ ○ ○ ○ ○ ○ ○ Residual ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Fixed △ △ ○ ○ ○ ○ ○ ○ ○ ○ Separability ○ ○ ○ ○ ○ ○ ○ ○ △ △ Substrate layer PET PET PET PET PET PET PET PET PET PET Second adhesive layer 15° peeling strength at 23°C (N/20mm) 20 20 20 20 2 15 twenty two 50 70 100 15° peeling adhesion after heating at 150℃ for 4 hours (N/20mm) 40 40 40 40 3 20 41 100 120 130 Energy storage modulus at 23℃(Pa) 1.2×10 ⁵ 1.2×10 ⁵ 1.2×10 ⁵ 1.2×10 ⁵ 2.5×10 ⁵ 1.8×10 ⁵ 1×10 ⁵ 0.9×10 ⁵ 0.9×10 ⁵ 0.8×10 ⁵ Storage modulus at 150℃(Pa) 0.7×10 ⁵ 0.7×10 ⁵ 0.7×10 ⁵ 0.7×10 ⁵ 1.6×10 ⁵ 1.2×10 ⁵ 0.6×10 ⁵ 0.6×10 ⁵ 0.5×10 ⁵ 0.5×10 ⁵ Gel rate (%) 70 70 70 70 90 75 60 55 50 40 Weight average molecular weight of the soluble part of the binder 4000 4000 4000 4000 2000 3000 5000 5300 5700 6000 Thickness(μm) 25 25 25 25 25 25 25 25 25 25 Fixed ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Separability ○ ○ ○ ○ ○ ○ ○ ○ △ △ Comprehensive evaluation △ △ ○ ○ ○ ○ ○ ○ △ △

Table 4 Comparison Example 1 Comparison Example 2 Comparison Example 3 Comparison Example 4 First adhesive layer Adhesive composition D1 D2 D3 D4 180° peeling strength at 23℃ N1 (N/20mm) 0.07 0.04 2.3 3.3 180° peeling adhesion after heating at 130℃ for 5 minutes N2 (N/20mm) 0.15 0.11 5.7 7.2 N2/N1 2.14 2.75 2.48 2.18 Energy storage modulus at 23℃(Pa) 15×10 ⁵ 14×10 ⁵ 0.2×10 ⁵ 0.1×10 ⁵ Thickness(μm) 3 2 55 70 Encapsulation × × ○ ○ Residual ○ ○ ○ × Fixed × × ○ ○ Separability ○ ○ × × Substrate layer PET PET PET PET Second adhesive layer 15° peeling strength at 23°C (N/20mm) 1 1 120 120 15° peeling adhesion after heating at 150℃ for 4 hours (N/20mm) 2 2 160 160 Energy storage modulus at 23℃(Pa) 2.8×10 ⁵ 2.8×10 ⁵ 0.6×10 ⁵ 0.6×10 ⁵ Storage modulus at 150℃(Pa) 1.9×10 ⁵ 1.9×10 ⁵ 0.4×10 ⁵ 0.4×10 ⁵ Gel rate (%) 91 91 40 40 Weight average molecular weight of the soluble part of the binder 2000 2000 10000 10000 Thickness(μm) 2 2 60 60 Fixed × × ○ ○ Separability ○ ○ × × Comprehensive evaluation × × × ×

As can be seen from Table 3, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can support the chip so that the chip does not shift during the resin encapsulation step, reducing the deviation of the chip from the specified position. In addition, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention can be easily peeled off after use, and there is no residual glue contamination to the encapsulation resin and the chip after encapsulation.

However, in Comparative Examples 1 to 4, as shown in Table 4, the chip deviates from the designated position and is difficult to peel off after use, resulting in residual glue contamination after peeling.

Industrial Applicability The present invention can provide a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, which is used to temporarily fix a chip when producing a substrate-less semiconductor package. The above-mentioned adhesive sheet supports the chip during the resin encapsulation step and can reduce residual adhesive due to the subsequent heat treatment by curing of the pressure-sensitive adhesive layer. In addition, the above-mentioned adhesive sheet can support the chip with certainty during the resin encapsulation step, and the chip is less likely to deviate from the specified position.

1: Wafer 2: Heat-resistant pressure-sensitive adhesive sheet for semiconductor device production 3: Substrate 4: Encapsulation resin 5: Electrode 6: Cutting knife 7: Cutting ring 8: Cutting tape 9: Residue adhesive 10: First release film 11: Base material layer 12: First adhesive layer 13: Second adhesive layer 14: Second release film

Figures 1(a) to (h) are flow charts showing the steps of producing a substrate-free BGA using the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention. Figures 2A to 2F are schematic diagrams showing a method for producing a substrate-free package. Figures 3A and 3B are comparison diagrams of a case where the chip is not involved in deviation and a case where the chip is involved in deviation. Figures 4(a) and (b) are diagrams showing a heat-resistant pressure-sensitive adhesive sheet for semiconductor device production, which has a chip mounted thereon that is deformed by heating when encapsulated with an encapsulating resin. Figure 5 is a diagram showing the occurrence of charging and residual adhesive when peeling off the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production. Figure 6 is a cross-sectional view of the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention. FIG. 7 is a cross-sectional view of another example of the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production of the present invention.

2: Heat-resistant pressure-sensitive adhesive sheets for semiconductor device production

11: Base material layer

12: First adhesive layer

Claims (10)

A heat-resistant pressure-sensitive adhesive sheet for producing semiconductor devices, characterized in that it comprises: a substrate layer; and a first adhesive layer disposed on one side of the substrate layer, wherein the first adhesive layer comprises an acrylic polymer and a crosslinking agent, wherein the acrylic polymer comprises 0.5 to 4 parts by weight of a hydroxyl-containing monomer and 1 to 4 parts by weight of a carboxyl-containing monomer based on 100 parts by weight of all monomer components of the acrylic polymer, and the crosslinking agent comprises an epoxy crosslinking agent and an isocyanate crosslinking agent, wherein the epoxy crosslinking agent comprises an isocyanate crosslinking agent and an isocyanate crosslinking agent. The amount of the crosslinking agent used is 0.1-2 parts by weight relative to 100 parts by weight of the acrylic polymer, the amount of the isocyanate crosslinking agent used is 1-2 parts by weight relative to 100 parts by weight of the acrylic polymer, and the ratio of the 180° peeling adhesion N2 of the first adhesive layer relative to the stainless steel plate after heating at 100-150°C for 3-10 minutes to the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate at 20-25°C, that is, N2/N1

2. For example, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 1, wherein the 180° peeling adhesion N1 of the first adhesive layer relative to the stainless steel plate at 20~25°C is 0.1~3.0N/20mm; the 180° peeling adhesion N2 of the first adhesive layer relative to the stainless steel plate after heating at 100~150°C for 3~10 minutes is 0.2~6.0N/20mm. A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 1 or 2, wherein the first adhesive layer comprises an acrylic adhesive; the gelation rate of the first adhesive layer is greater than 70%; and/or the energy storage modulus G' of the first adhesive layer at 20-25°C is 0.5×10 ⁵ -12×10 ⁵ Pa; and/or the weight average molecular weight of the soluble part of the acrylic adhesive is less than 80,000. A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 1 or 2, wherein the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production also includes a second adhesive layer, the second adhesive layer is disposed on a side of the substrate layer opposite to the first adhesive layer; the second adhesive layer has a 15° peeling adhesion of 2 to 100 N/20 mm relative to a stainless steel plate at 20 to 25°C; the second adhesive layer has a 15° peeling adhesion of 3 to 130 N/20 mm relative to a stainless steel plate after being heated at 150°C for 4 hours. The heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 4, wherein the energy storage modulus G' of the second adhesive layer at 20-25°C is 0.8×10 ⁵ -2.5×10 ⁵ Pa; the energy storage modulus G' of the second adhesive layer at 150°C is 0.5×10 ⁵ -1.6×10 ⁵ Pa. For example, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 4, wherein the gelation rate of the second adhesive layer is 40-90%; and the weight average molecular weight of the soluble part of the adhesive in the second adhesive layer is 2,000-6,000. A heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 1 or 2, wherein the substrate layer is selected from at least one of the group consisting of polyester film, polyamide film, polyimide film, polyphenylene sulfide film, polyetherimide film, polyamideimide film, polysulfone film, polyetherketone film, polytetrafluoroethylene film, ethylene-tetrafluoroethylene copolymer film, perfluoroethylene-propylene copolymer film, polyvinylidene fluoride film, polychlorotrifluoroethylene film, and an alternating copolymer film of ethylene and chlorotrifluoroethylene in a molar ratio of 1:1. As in claim 4, the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production also includes a first release film and a second release film, wherein the first release film is disposed on a side of the first adhesive layer opposite to the substrate layer, and the second release film is disposed on a side of the second adhesive layer opposite to the substrate layer. As for the heat-resistant pressure-sensitive adhesive sheet for semiconductor device production as claimed in claim 4, the thickness of the first adhesive layer is 5 to 50 μm; the thickness of the second adhesive layer is 5 to 50 μm. A method for producing a semiconductor device, characterized in that the method comprises using the heat-resistant pressure-sensitive adhesive sheet for producing a semiconductor device as described in any one of claims 1 to 9.