Thermosetting adhesive composition, laminated film, and connected body and method for producing same

Abstract

Disclosed is a thermosetting adhesive composition containing an epoxy resin, a phenolic resin, an elastomer, and a hardening accelerant. After being heated at 95℃ for 3 hours, the reaction percentage of the thermosetting adhesive composition is 50% or more, and the ratio of the storage modulus at 35℃ to the storage modulus at 85℃ is 20 or less.

Description

Thermosetting adhesive composition, laminated film, and connection body, and method for producing the same

[0001] The present disclosure relates to a thermosetting adhesive composition, a laminated film, a connection body, and a method for producing the same.

[0002] Conventionally, semiconductor devices are manufactured through the following steps. First, a dicing process is performed with a semiconductor wafer attached to a dicing adhesive sheet, thereby dividing the semiconductor wafer into individual semiconductor chips. Then, a pickup process, a die bonding process, a wire bonding process, a molding process, and the like are performed. Patent Document 1 discloses an adhesive sheet (die bond dicing sheet) that has both the function of fixing a semiconductor wafer in a dicing process and the function of bonding a semiconductor chip to a substrate in a die bonding process. Patent Document 2 discloses an adhesive sheet that acts as a dicing tape in a dicing process, has excellent connection reliability in a process of bonding a semiconductor element to a support member, and retains sufficient fluidity after the heat history of wire bonding.

[0003] JP 2007-288170 A JP 2009-209345 A

[0004] In recent years, with the evolution of semiconductor modules for small devices such as smartphones, the manufacturing process for semiconductor modules has also changed significantly from conventional methods. For example, processes that do not involve dicing or die bonding are being put into practical use. Accordingly, thermosetting adhesive compositions used in the manufacturing process for semiconductor modules are also required to have different performance than conventional ones. Since it is expected that semiconductor modules will use materials with relatively low heat resistance, there is a need for the development of thermosetting adhesive compositions that can be used in low-temperature curing processes, for example, at temperatures below 100°C.

[0005] A primary object of the present disclosure is to provide a thermosetting adhesive composition that is applicable to a low-temperature curing process and is capable of forming an adhesive layer that exhibits high adhesive strength.

[0006]

[0006] In order to apply a thermosetting adhesive composition to a low-temperature curing process, it is usually necessary for the composition to have low-temperature curing properties, so that curing proceeds sufficiently when heated at low temperatures. In response to this, the present inventors conducted research while also focusing on cases where curing does not proceed sufficiently when heated at low temperatures (unreacted components remain). As a result, they found that an adhesive layer exhibiting high adhesive strength can be obtained by using a thermosetting adhesive composition that shows a certain level of reaction rate or higher and has a small rate of change in storage modulus at a predetermined temperature, and thus completed the invention of the present disclosure.

[0007] The present disclosure provides thermosetting adhesive compositions according to [1] to

[14] , a laminate film according to

[15] , methods for producing a connection body according to

[16] and

[17] , and a connection body according to

[18] . [1] A thermosetting adhesive composition containing an epoxy resin, a phenolic resin, an elastomer, and a curing accelerator, wherein after heating at 95°C for 3 hours, the thermosetting adhesive composition has a reaction rate of 50% or more and a ratio of the storage modulus at 35°C to the storage modulus at 85°C of 20 or less. [2] The thermosetting adhesive composition according to [1], which has a shear viscosity at 95°C of 100 to 12,000 Pa s. [3] The thermosetting adhesive composition according to [1] or [2], which has a storage modulus at 35°C of 1,000 MPa or less after heating at 95°C for 3 hours. [4] The thermosetting adhesive composition according to any one of [1] to [3], wherein the storage modulus at 85°C after heating at 95°C for 3 hours is 5 MPa or more. [5] The thermosetting adhesive composition according to any one of [1] to [4], wherein the storage modulus at 85°C after heating at 95°C for 3 hours is 50 MPa or more. [6] The thermosetting adhesive composition according to any one of [1] to [5], wherein the conversion is 85% or less. [7] The thermosetting adhesive composition according to any one of [1] to [6], wherein the ratio of the storage modulus at 35°C to the storage modulus at 85°C is 6 or less. [8] The thermosetting adhesive composition according to any one of [1] to [7], wherein the phenolic resin comprises a phenolic resin having a hydroxyl equivalent of 150 g / eq or less. [9] The thermosetting adhesive composition according to any one of [1] to [8], wherein the phenolic resin comprises a phenolic resin having a softening point of 150°C or less.

[10] The thermosetting adhesive composition according to any one of [1] to [9], wherein the phenolic resin comprises a phenol novolac resin.

[11] The thermosetting adhesive composition according to any one of [1] to

[10] , wherein the epoxy resin comprises a solid epoxy resin.

[12] The thermosetting adhesive composition according to any one of [1] to

[11] , wherein the curing accelerator is a compound that generates a heterocyclic amine compound upon heating.

[13] The thermosetting adhesive composition according to any one of [1] to

[12] , wherein the content of the epoxy resin is 20 to 35 mass %, the content of the phenolic resin is 10 to 30 mass %, the content of the elastomer is 15 to 50 mass %, and the content of the curing accelerator is 5 to 20 mass %, based on the total amount of the thermosetting adhesive composition.

[14] The thermosetting adhesive composition according to any one of [1] to

[13] , further containing an inorganic filler.

[15] A laminated film comprising: a substrate film; and an adhesive layer provided on a surface of the substrate film, wherein the adhesive layer is constituted by the thermosetting adhesive composition according to any one of [1] to

[14] .

[16] A method for manufacturing a connection body, comprising the steps of: (A) preparing a laminate comprising a first circuit member, a second circuit member, and an adhesive layer disposed between the first circuit member and the second circuit member; (B) heating the laminate at 90 to 110°C for 30 to 240 minutes; and (C) wire-bonding the first circuit member and the second circuit member, wherein the adhesive layer is formed from the thermosetting adhesive composition described in [1] to

[14] .

[17] A method for manufacturing a connection body according to

[16] , wherein the first circuit member is one selected from the group consisting of a printed circuit board and a semiconductor chip, and the second circuit member is a flexible printed circuit board.

[18] A connection body comprising: a first circuit member, a second circuit member, and an adhesive layer disposed between the first circuit member and the second circuit member, wherein the adhesive layer is formed from a cured product of the thermosetting adhesive composition described in [1] to

[14] .

[0008] The present disclosure provides a thermosetting adhesive composition that can be applied to a low-temperature curing process and that can form an adhesive layer that exhibits high adhesive strength. The present disclosure also provides a laminated film that includes an adhesive layer made of such a thermosetting adhesive composition. The present disclosure also provides a connection structure that uses such a thermosetting adhesive composition and a method for manufacturing the same.

[0009] FIG. 1 is a cross-sectional view schematically showing an embodiment of a laminate film according to the present disclosure. FIG. 2 is a cross-sectional view schematically showing a semiconductor module during a manufacturing process. FIG. 3 is a cross-sectional view schematically showing a semiconductor module during a manufacturing process. FIG. 4 is a perspective view schematically showing an example of a punched product according to the present disclosure. FIG. 5 is a cross-sectional view taken along line V-V shown in FIG. 4. FIG. 6 is a cross-sectional view schematically showing how an adhesive piece and a cover film covering the adhesive piece are picked up from a base film. FIG. 7 is a cross-sectional view schematically showing a semiconductor module during a manufacturing process.

[0010] The present embodiment will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including steps, etc.) are not essential unless otherwise specified. The same or equivalent parts are given the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. The sizes of the components in each figure are conceptual, and the relative size relationships between the components are not limited to those shown in each figure.

[0011] The same applies to the numerical values ​​and ranges in the present disclosure, and do not limit the present disclosure. In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this specification, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in this specification, the upper limit or lower limit of that numerical range may be replaced with a value shown in the examples. Furthermore, the upper limit and lower limit values ​​described individually can be combined in any combination.

[0012] In this specification, the term "layer" includes not only a structure having a shape formed over the entire surface when observed in a plan view, but also a structure having a shape formed on a portion thereof. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0013] In this specification, "(meth)acrylate" means at least one of an acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryloyl" and "(meth)acrylic acid." Furthermore, "(poly)" refers to both cases with and without the prefix "poly."

[0014] "A or B" means that either A or B is contained, or both are contained. Furthermore, unless otherwise specified, the materials exemplified below may be used alone or in combination of two or more. When a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified.

[0015] [Laminate Film] Figure 1 is a cross-sectional view schematically illustrating a laminate film according to this embodiment. The laminate film 10 shown in this figure comprises a substrate film 1, an adhesive layer 3, and a cover film 5, in this order. The laminate film 10 has a width of 300 to 500 mm and a total length of 10 to 400 m, for example, and is produced by being wound into a roll. The configuration of the laminate film 10 will be described below.

[0016] <Substrate Film> There are no particular limitations on the substrate film 1, as long as it can sufficiently withstand the tension applied in the manufacturing process of the adhesive layer 3 and the manufacturing process of the semiconductor module. The substrate film 1 is preferably transparent from the viewpoint of visibility of the adhesive layer 3 disposed thereon. Examples of the substrate film 1 include polyester-based films such as polyethylene terephthalate films; polyolefin-based films such as homopolymers or copolymers, or mixtures thereof, of polytetrafluoroethylene films, polyethylene films, polypropylene films, polymethylpentene films, polyvinyl acetate films, poly-4-methylpentene-1, ethylene-vinyl acetate copolymers, and ethylene-ethyl acrylate copolymers; and plastic films such as polyvinyl chloride films and polyimide films. The substrate film 1 may have a single-layer structure or a multilayer structure.

[0017] The thickness of the base film 1 may be appropriately selected within a range that does not impair workability, and may be, for example, 10 to 200 μm, 20 to 100 μm, or 25 to 80 μm. These thickness ranges are practically acceptable and economically effective.

[0018] In order to increase the adhesive strength of the adhesive layer 3 to the base film 1, the surface of the base film 1 may be subjected to a chemical or physical surface treatment such as corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, or ionizing radiation treatment. A film made of a fluororesin and having low surface energy can also be used as the base film 1. Examples of such films include A-63 (release treatment agent: modified silicone-based) manufactured by Toyobo Film Solutions Co., Ltd. and A-31 (release treatment agent: Pt-based silicone-based) manufactured by Toyobo Film Solutions Co., Ltd.

[0019] In order to prevent the adhesive strength of the adhesive layer 3 to the base film 1 from becoming excessively high, a release layer composed of a release agent such as a silicone-based release agent, a fluorine-based release agent, or a long-chain alkyl acrylate-based release agent may be formed on the surface of the base film 1.

[0020] The adhesion strength between the base film 1 and the adhesive layer 3 is, for example, 0.5 N / m or more. When this adhesion strength is 0.5 N / m or more, it is easy to prevent the adhesive layer 3 from accidentally peeling off from the base film 1 during the process of producing the laminate film 10. The adhesion strength of the adhesive layer 3 to the base film 1 means the 90° peel strength, and specifically means the peel strength measured when a 20 mm wide sample having the adhesive layer 3 formed on the base film 1 is prepared, and this adhesive layer is peeled off from the base film at an angle of 90° at a peel rate of 50 mm / min.

[0021] <Adhesive Layer> The adhesive layer 3 is used to bond circuit components together, and is suitably used, for example, to bond the leading end of a printed circuit board to an FPC board (flexible printed circuit board) or to bond a semiconductor chip to an FPC board. The module 50A (connected body) shown in FIG. 2 includes a semiconductor chip C, a printed circuit board 12 (first circuit member), an adhesive piece 3c, and an FPC board 15 (second circuit member). The adhesive piece 3c bonds the printed circuit board 12 to the leading end 15a of the FPC board 15. The adhesive piece 3c is composed of a cured product of the adhesive piece 3p (see FIG. 4). The adhesive piece 3p is formed by cutting the adhesive layer 3 shown in FIG. 1 into a predetermined shape by die-cutting. The adhesive layer 16 bonds the printed circuit board 12 to the semiconductor chip C. The adhesive layer 16 may have the same composition as the adhesive piece 3c, or a different composition.

[0022] The module 50B shown in Fig. 3 is obtained by performing wire bonding on the module 50A shown in Fig. 2. A wire W1 electrically connects the semiconductor chip C to the printed circuit board 12, and a wire W2 electrically connects the printed circuit board 12 to the FPC board 15. The semiconductor chip C is, for example, a sensor chip. The printed circuit board 12 processes signals from the semiconductor chip C. Signals from the printed circuit board 12 are transmitted to the tip portion 15a of the FPC board 15.

[0023] The adhesive piece 3p (adhesive layer) is made of a thermosetting adhesive composition (hereinafter, sometimes simply referred to as "adhesive composition"). The adhesive composition contains an epoxy resin, a phenolic resin, an elastomer, and a curing accelerator. The adhesive composition may also contain an inorganic filler.

[0024] Epoxy Resin: The epoxy resin may contain at least one selected from the group consisting of solid epoxy resins that are solid at 25°C and liquid epoxy resins that are liquid at 25°C. In one embodiment, the epoxy resin may contain a solid epoxy resin. Examples of epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, alicyclic epoxy resins, linear aliphatic epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, diglycidyl ethers of biphenols, diglycidyl ethers of naphthalenediols, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and difunctional epoxy resins and novolac epoxy resins such as alkyl-substituted, halide, and hydrogenated versions thereof. Other commonly known epoxy resins, such as multifunctional epoxy resins and heterocycle-containing epoxy resins, may also be used. Components other than the epoxy resin may be contained as impurities to the extent that they do not impair the properties.

[0025] Specific examples of solid epoxy resins include YDCN-700-10 (trade name, manufactured by Nippon Steel Chemical & Material Co., Ltd., cresol novolac type epoxy resin, epoxy equivalent: 210 g / eq, softening point: 80°C), N-500P-10 (trade name, manufactured by DIC Corporation, cresol novolac type epoxy resin, epoxy equivalent: 204 g / eq, softening point: 84°C), HP-4710 (trade name, manufactured by DIC Corporation, naphthalene type epoxy resin, epoxy equivalent: 170 g / eq, softening point: 95°C), and NC-7000L (trade name, manufactured by Nippon Kayaku Co., Ltd., naphthalene type epoxy resin, epoxy equivalent: 230 g / eq, softening point: 88°C).

[0026] Specific examples of liquid epoxy resins include YDF-8170C (trade name, manufactured by Nippon Steel Chemical & Material Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent: 165 g / eq) and EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol F type epoxy resin, epoxy equivalent: 159 g / eq).

[0027] The softening point of the epoxy resin can be measured by, for example, the ring and ball method in accordance with JIS K7234: 1986. Alternatively, the softening point of the epoxy resin may be, for example, a value listed in the catalogue of a distributor.

[0028] The epoxy equivalent of the epoxy resin is not particularly limited, but may be 80 to 350 g / eq, 100 to 300 g / eq, or 120 to 250 g / eq. The epoxy equivalent of the epoxy resin can be measured, for example, by potentiometric titration in accordance with JIS K7236:2009. Alternatively, the epoxy equivalent of the epoxy resin may be, for example, the value listed in the catalog of the distributor.

[0029] The content of the epoxy resin is, for example, 10 to 45 mass %, or may be 15 to 40 mass %, or 20 to 35 mass %, based on the total amount of the adhesive composition. The total amount of the adhesive composition means the total amount of solids excluding the organic solvent. The same applies hereinafter. When the content of the epoxy resin is within the above range, sufficient thermosetting properties are obtained, and curing tends to proceed even at low temperatures.

[0030] Phenolic Resin The phenolic resin may contain at least one selected from the group consisting of solid phenolic resins that are solid at 25° C. and liquid phenolic resins that are liquid at 25° C. In one embodiment, the phenolic resin may contain a solid phenolic resin. There are no particular limitations on the phenolic resin as long as it has a phenolic hydroxyl group in the molecule. Examples of phenolic resins include phenol novolac resins obtained by condensing or co-condensing phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and / or naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene with compounds having an aldehyde group such as formaldehyde, under an acidic catalyst; and phenol aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl phenolic resins, and phenyl aralkyl phenolic resins, which are synthesized from phenols such as allylated bisphenol A, allylated bisphenol F, allylated naphthalenediol, phenol novolac, and / or naphthols with dimethoxyparaxylene or bis(methoxymethyl)biphenyl. The phenolic resin may include a phenol novolac resin.

[0031] Specific examples of solid phenolic resins include MEH-7500 (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), trisphenylmethane type phenolic novolac resin, hydroxyl equivalent: 97 g / eq, softening point: 110°C), H-4 (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenylaralkyl type phenolic resin, hydroxyl equivalent: 105 g / eq, softening point: 69°C), PSM-4326 (trade name, manufactured by Gunei Chemical Industry Co., Ltd., phenolic novolac resin, hydroxyl equivalent: 105 g / eq, softening point: 120°C), HF-1M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenolic novolac resin, hydroxyl equivalent: 106 g / eq, softening point: 84°C), and H Examples of suitable phenolic resins include F-3M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenol novolac resin, hydroxyl equivalent: 107 g / eq, softening point: 96°C), MEH-7800-4S (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), xylylene phenol resin, hydroxyl equivalent: 173 g / eq, softening point: 63°C), MEH-7800M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenylaralkyl phenol resin, hydroxyl equivalent: 174 g / eq, softening point: 82°C), and MEHC-7851SS (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), biphenyl phenol novolac resin, hydroxyl equivalent: 203 g / eq, softening point: 67°C).

[0032] A specific example of the liquid phenolic resin is MEH-8000H (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenol novolac resin, hydroxyl equivalent: 141 g / eq).

[0033] The phenolic resin may contain a phenolic resin having a hydroxyl equivalent of 150 g / eq or less. By containing a phenolic resin having a hydroxyl equivalent of 150 g / eq or less, the reactivity and storage modulus tend to be easily adjusted within a predetermined range. The hydroxyl equivalent of the phenolic resin may be 140 g / eq or less, 120 g / eq or less, or 110 g / eq or less, or 80 g / eq or more, or 90 g / eq or more. The hydroxyl equivalent of the phenolic resin can be measured, for example, by titration using an acetylation method using acetic anhydride. The hydroxyl equivalent of the phenolic resin may also be, for example, a catalog value from a distributor.

[0034] The phenolic resin may contain a phenolic resin having a softening point of 150°C or less. When the phenolic resin contains a phenolic resin having a softening point of 150°C or less, the reactivity and storage modulus tend to be easily adjusted to a predetermined range. The softening point of the phenolic resin may be 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less, or may be 50°C or more, 60°C or more, or 65°C or more. The softening point of the phenolic resin can be measured, for example, by the ring and ball method in accordance with JIS K6910:2007. For example, the softening point of the phenolic resin may be a value listed in the catalog of a distributor.

[0035] The content of the phenolic resin is, for example, 1 to 40 mass %, or may be 5 to 35 mass %, or 10 to 30 mass %, based on the total amount of the adhesive composition. When the content of the phenolic resin is within the above range, sufficient thermosetting properties are obtained, and curing tends to proceed even at low temperatures.

[0036] The total content of the epoxy resin and the phenolic resin is, for example, 25 to 65 mass %, or may be 30 to 60 mass %, or 35 to 55 mass %, based on the total amount of the adhesive composition. When the total content of the epoxy resin and the phenolic resin is within the above range, shrinkage due to thermal curing of the adhesive layer 3 can be suppressed, and excellent adhesion after thermal curing tends to be easily achieved.

[0037] As the elastomer, a thermoplastic resin or a resin that is thermoplastic at least in an uncured state and forms a crosslinked structure after heating can be used. The elastomer may be a (meth)acrylic copolymer having a reactive group (hereinafter, also referred to as a "reactive group-containing (meth)acrylic copolymer") from the viewpoint of excellent shrinkage, heat resistance, and peelability. The elastomer may include at least one selected from the group consisting of a liquid elastomer that is liquid at 25°C and a solid elastomer that is solid at 25°C. In one embodiment, the elastomer may include a solid elastomer.

[0038] Examples of the (meth)acrylic copolymer include (meth)acrylic acid ester copolymers such as acrylic glass and acrylic rubber. The (meth)acrylic copolymer may be acrylic rubber. The acrylic rubber may be formed by copolymerizing an acrylic acid ester as a main component and a monomer selected from a (meth)acrylic acid ester and acrylonitrile.

[0039] Examples of (meth)acrylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, etc. Examples of (meth)acrylic acid ester copolymers include copolymers containing butyl acrylate and acrylonitrile as copolymerization components, and copolymers containing ethyl acrylate and acrylonitrile as copolymerization components.

[0040] The reactive group-containing (meth)acrylic copolymer may be a reactive group-containing (meth)acrylic copolymer containing a (meth)acrylic monomer having a reactive group as a copolymerization component. Such a reactive group-containing (meth)acrylic copolymer can be obtained by copolymerizing a monomer mixture containing the reactive group-containing (meth)acrylic monomer and the above-mentioned monomer.

[0041] From the viewpoint of improving heat resistance, examples of the reactive group include an epoxy group, a carboxyl group, a (meth)acryloyl group, a hydroxyl group, an episulfide group, etc. From the viewpoint of crosslinkability, the reactive group may be an epoxy group or a carboxyl group.

[0042] In this embodiment, the reactive group-containing (meth)acrylic copolymer may be an epoxy group-containing (meth)acrylic copolymer containing an epoxy group-containing (meth)acrylic monomer as a copolymerization component. In this case, examples of the epoxy group-containing (meth)acrylic monomer include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. From the viewpoint of heat resistance, the reactive group-containing (meth)acrylic monomer may be glycidyl (meth)acrylate.

[0043] The glass transition temperature (Tg) of the elastomer is, for example, -50 to 20°C, and may be -30 to 15°C. When the Tg of the elastomer is -50°C or higher, it is easy to prevent the adhesive layer 3 from becoming excessively soft, and excellent handleability and adhesiveness can be achieved. On the other hand, when the Tg of the elastomer is 20°C or lower, it is easy to ensure the flexibility of the adhesive layer 3, and excellent adhesive strength can be achieved. In addition, even if there are irregularities on the adherend surface, the adhesive layer 3 can easily follow the irregularities, and excellent adhesiveness can be achieved.

[0044] The Tg of an elastomer is the midpoint glass transition temperature obtained by differential scanning calorimetry (DSC). Specifically, the Tg of an elastomer is the midpoint glass transition temperature calculated by a method in accordance with JIS K7121:1987, measuring the change in calorific value under conditions of a temperature rise rate of 10°C / min and a measurement temperature of -80 to 80°C. Note that if the elastomer is a commercially available product, the value listed in the catalog or the like may be used.

[0045] The weight average molecular weight of the elastomer may be 100,000 to 2,000,000. When the weight average molecular weight is 100,000 or more, heat resistance is easily ensured. On the other hand, when the weight average molecular weight is 2,000,000 or less, deterioration in flow and adhesion is easily suppressed. The weight average molecular weight of the elastomer may be 400,000 to 1,500,000 or 500,000 to 1,200,000. The weight average molecular weight is a polystyrene-equivalent value obtained by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene.

[0046] The content of the elastomer is, for example, 5 to 60 mass %, or may be 10 to 55 mass %, or 15 to 50 mass %, based on the total amount of the adhesive composition. When the content of the elastomer is within the above range, shrinkage due to thermal curing of the adhesive layer 3 can be suppressed, and excellent adhesion after thermal curing tends to be easily achieved.

[0047] Curing Accelerator The curing accelerator may include at least one selected from the group consisting of liquid curing accelerators that are liquid at 25°C and solid curing accelerators that are solid at 25°C. In one embodiment, the curing accelerator may include a liquid curing accelerator. The curing accelerator may be, for example, a compound that generates a heterocyclic amine compound upon heating. Examples of the curing accelerator include a compound that generates a heterocyclic amine compound by deprotecting a protecting group upon heating (hereinafter, sometimes referred to as a "first compound"), and an ionic compound that generates a heterocyclic amine compound upon heating (hereinafter, sometimes referred to as a "second compound"). The first compound can be said to be a compound in which an amino group contained in the heterocycle of a heterocyclic amine compound is protected by a protecting group. Among these, the curing accelerator may be the first compound.

[0048] Adhesive compositions containing a first compound or a second compound as a curing accelerator generate a heterocyclic amine compound with curing-accelerating properties upon heating, thereby exhibiting thermosetting properties. Therefore, even if the adhesive composition is not used immediately after preparation but is stored for a certain period of time, the curing reaction of the epoxy resin is sufficiently inhibited. That is, the increase in shear viscosity of the adhesive composition over time is sufficiently inhibited, allowing the adhesive composition to remain usable for a relatively long period of time (e.g., more than two weeks) after preparation, thereby achieving a sufficiently long work life. In addition, the adhesive composition is also useful for achieving heat curing treatments at low temperatures below 100°C. That is, thermosetting resins with excellent low-temperature curing properties tend to undergo a curing reaction more easily when stored in a state mixed with a curing accelerator. However, since the above-mentioned curing accelerator exhibits its function by being deprotected by heating during use, the curing reaction of the epoxy resin is inhibited during storage. Such adhesive compositions can achieve both a long work life and low-temperature curing properties at a sufficiently high level.

[0049] Examples of heterocyclic amine compounds generated from compounds that generate heterocyclic amine compounds upon heating include compounds having a pyrrolidine ring, a piperidine ring, a piperazine ring, a morpholine ring, an oxazine ring, a quinuclidine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an oxazole ring, a thiazole ring, etc. In these rings, some of the hydrogen atoms directly bonded to the carbon atoms constituting the ring may be substituted with a substituent. The substituent is a group commonly used in the field of organic chemistry. Examples of the substituent include a halogen atom, a hydroxy group, an amino group, a sulfonic acid group, a nitro group, a cyano group, an alkyl group, an aryl group, an alkoxy group, a substituted amino group, etc. Among these, the heterocyclic amine compound may be, for example, an aromatic heterocyclic amine compound, and may be, for example, a compound having a pyrazole ring or a compound having an imidazole ring.

[0050] The protecting group in the first compound is a protecting group that protects an amino group contained in the heterocycle of the heterocyclic amine compound. The protecting group may be a group that is commonly used as a protecting group for an amino group in the field of organic chemistry. Examples of the protecting group include a tosyl group, a methoxymethyl group, a benzyloxymethyl group, an allyl group, a triisopropylsilyl group, a benzyl group, a methoxycarbonyl group, a p-methoxybenzyl group, and a p-methoxyphenyl group.

[0051] The protecting group in the first compound may, in one embodiment, be a substituted amide group. A substituted amide group is, for example, —C(O)N(R １ ) (R ２ ) represented by the group (R １ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms in which some of the hydrogen atoms directly bonded to the carbon atom may be substituted with (meth)acryloyloxy groups, and R ２ represents an alkyl group having 1 to 10 carbon atoms in which some of the hydrogen atoms directly bonded to the carbon atom may be substituted with (meth)acryloyloxy groups.

[0052] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an isopropyl group, and an isobutyl group.

[0053] Specific examples of the first compound include Karenz MOI-BP (trade name, manufactured by Resonac Corporation, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, "Karenz" is a registered trademark, liquid at 25°C), Karenz AOI-BP (trade name, manufactured by Resonac Corporation, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl acrylate, solid at 25°C), and the like.

[0054] Examples of the second compound include pyrazonium salt compounds, imidazolium salt compounds, etc. A specific example of the second compound includes EMZ-K (trade name, manufactured by Hokko Sangyo Co., Ltd., 2-ethyl-4-methylimidazolium tetraphenylborate, "EMZ-K" is a registered trademark, solid at 25°C).

[0055] The content of the curing accelerator is, for example, 1 to 25 mass %, or may be 3 to 22 mass %, or 5 to 20 mass %, based on the total amount of the adhesive composition. When the content of the curing accelerator is within the above range, the effects of the present disclosure tend to be easily and satisfactorily exhibited.

[0056] Inorganic Filler: The inorganic filler can be selected depending on the desired function. Examples of inorganic fillers include metal (conductive) fillers such as silver powder, gold powder, and copper powder; and non-metal (insulating) fillers such as silica, alumina, boron nitride, titania, glass, iron oxide, and ceramic. The inorganic filler may be, for example, a silica filler.

[0057] The surface of the inorganic filler may have an organic group. By modifying the surface of the inorganic filler with an organic group, dispersibility in an organic solvent can be improved when preparing a varnish for forming the adhesive layer 3. In addition, shrinkage associated with thermal curing of the adhesive layer 3 can be suppressed, and the adhesive layer 3 tends to easily achieve both a high elastic modulus and excellent releasability. An inorganic filler having an organic group on its surface can be obtained, for example, by mixing a silane coupling agent represented by the following formula (B-1) with the inorganic filler and stirring at a temperature of 30°C or higher. Whether the surface of the inorganic filler has been modified with an organic group can be confirmed by ultraviolet-visible spectroscopy, infrared absorption spectroscopy, X-ray photoelectron spectroscopy, or the like.

[0058]

[0059] In formula (B-1), X represents an organic group selected from the group consisting of a phenyl group, a glycidoxy group, a (meth)acryloyloxy group, a mercapto group, an amino group, a vinyl group, and an isocyanate group; s represents 0 or an integer of 1 to 10; R １１ , R １２ , and R １３ each independently represents an alkyl group having 1 to 10 carbon atoms.

[0060] The alkyl group having 1 to 10 carbon atoms may be the same as the alkyl group having 1 to 10 carbon atoms exemplified above for the substituted amide group.

[0061] From the viewpoint of availability, the alkyl group having 1 to 10 carbon atoms may be a group selected from the group consisting of a methyl group, an ethyl group, and a pentyl group. From the viewpoint of heat resistance, X may be a group selected from the group consisting of an amino group, a glycidoxy group, a mercapto group, and an isocyanate group, and may be a glycidoxy group or a mercapto group.

[0062] s may be an integer of 0 to 5, or may be an integer of 0 to 4, from the viewpoint of suppressing the fluidity of the film at high temperatures and improving the heat resistance.

[0063] The content of the inorganic filler is, for example, 0 to 40% by mass, based on the total amount of the adhesive composition. In one embodiment, the content of the inorganic filler may be 5 to 35% by mass or 10 to 30% by mass, based on the total amount of the adhesive composition. By including an inorganic filler in the adhesive composition, the storage modulus can be further improved. When the content of the inorganic filler is 40% by mass or less, based on the total amount of the adhesive composition, the adhesive strength with a resin member or the like becomes sufficient, and a decrease in workability tends to be suppressed.

[0064] In one embodiment, the content of the inorganic filler may be 0 to 10% by mass, or 0 to 5% by mass, or may be 0% by mass, based on the total amount of the adhesive composition.

[0065] The adhesive composition may further contain other components. Examples of the other components include coupling agents such as silane coupling agents, and organic fillers such as carbon, rubber-based fillers, silicone-based fine particles, polyamide fine particles, and polyimide fine particles. The content of the other components may be 0 to 30 mass % based on the total amount of the adhesive composition.

[0066] The adhesive composition may be diluted with an organic solvent as needed, or may be used as an adhesive varnish. The organic solvent is not particularly limited, but can be determined taking into consideration the boiling point and volatility during film formation. Examples of organic solvents include relatively low-boiling point solvents such as methanol, ethanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, methyl ethyl ketone, acetone, methyl isobutyl ketone, toluene, and xylene; and relatively high-boiling point solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and cyclohexanone. Solvents with relatively low boiling points have the advantage that they do not easily promote film hardening during film formation. Solvents with relatively high boiling points have the advantage of improving film formability.

[0067] The adhesive composition has a reaction rate of 50% or more after being heated at 95°C for 3 hours, and the ratio of the storage modulus at 35°C to the storage modulus at 85°C after being heated at 95°C for 3 hours is 20 or less.

[0068] It is preferable that the adhesive composition undergoes a certain degree of curing reaction after heat treatment at 95°C for 3 hours. The degree of reaction progress can be quantified by differential scanning calorimetry. That is, the reaction rate calculated by the following formula from the calorific values ​​C1 and C2 determined from a DSC curve obtained by differential scanning calorimetry at a temperature rise rate of 10°C / min is 50% or more, and may be 55% or more, 60% or more, or 65% or more. Reaction rate (%) = (C1 - C2) / C1 × 100

[0069] The calorific value C1 is the calorific value (unit: J / g) measured for the adhesive composition. The calorific value C2 is the calorific value (unit: J / g) measured for the resin composition after heating the adhesive composition at 95°C for 3 hours. The temperature range for differential scanning calorimetry is, for example, 30 to 300°C. The temperature range for determining the calorific values ​​C1 and C2 from the DSC curve obtained by measurement is 50 to 200°C.

[0070] Since the adhesive composition can form an adhesive layer that exhibits high adhesive strength even when unreacted components remain, the reaction rate of the adhesive composition after heating at 95°C for 3 hours may be, for example, 100% or less, 95% or less, 90% or less, 85% or less, 80% or less, or 75% or less.

[0071] After heating the adhesive composition at 95°C for 3 hours, the ratio of the storage modulus at 35°C to the storage modulus at 85°C (storage modulus at 35°C / storage modulus at 85°C) is 20 or less, and may be 15 or less, 12 or less, 10 or less, 8 or less, or 6 or less. When the storage modulus ratio is 20 or less, it tends to be possible to form an adhesive layer that exhibits high adhesive strength. Furthermore, when the storage modulus ratio is 20 or less, temperature-related changes in physical properties are small, making it less likely that problems such as peeling due to physical property changes will occur, and improved reliability during product manufacturing can be expected. The storage modulus ratio may, for example, be greater than 1, 1.5 or more, or 2 or more.

[0072] The storage modulus of the adhesive composition at 35°C after heating at 95°C for 3 hours may be, for example, 1000 MPa or less, or may be 950 MPa or less, or 900 MPa or less. When the storage modulus at 35°C is 1000 MPa or less, warping of the resulting semiconductor module tends to be further suppressed. The storage modulus of the adhesive composition at 35°C after heating at 95°C for 3 hours may be 100 MPa or more, 200 MPa or more, 300 MPa or more, 400 MPa or more, or 500 MPa or more.

[0073] The storage modulus of the adhesive composition at 85°C after heating at 95°C for 3 hours may be, for example, 5 MPa or more, 10 MPa or more, 30 MPa or more, 50 MPa or more, 70 MPa or more, or 100 MPa or more. As the storage modulus at 85°C increases, process errors during wire bonding tend to be further reduced. The storage modulus of the adhesive composition at 85°C after heating at 95°C for 3 hours may be, for example, 500 MPa or less, 450 MPa or less, 400 MPa or less, or 350 MPa or less.

[0074] The storage modulus at 35°C and 85°C can be measured, for example, by the following procedure. First, multiple film-like adhesives made from the adhesive composition are prepared, each 25 μm thick. Next, multiple film-like adhesives are laminated to a thickness of approximately 300 μm, and this is cut into a size of 4 mm wide x 33 mm, and heated at 95°C for 3 hours to prepare a measurement sample. The prepared measurement sample is placed in a dynamic viscoelasticity apparatus with a chuck distance of 20 mm, and a tensile load is applied, and measurement is performed under conditions of a frequency of 10 Hz and a heating rate of 3°C / min to measure the storage modulus at 35°C and 85°C.

[0075] The following methods can be considered to adjust the reactivity and storage modulus within the predetermined ranges. Method (1): The hydroxyl group equivalent of the phenolic resin contained in the adhesive composition is relatively small. This tends to slightly increase the reactivity and increase the storage modulus. Method (2): The softening point of the phenolic resin contained in the adhesive composition is relatively low. This tends to slightly increase the reactivity and decrease the storage modulus. Method (3): The amount of inorganic filler contained in the adhesive composition is relatively small. This tends to slightly increase the reactivity and decrease the storage modulus. Method (4): The amount of elastomer (e.g., acrylic rubber) contained in the adhesive composition is relatively small. This tends to slightly increase the reactivity and increase the storage modulus. Method (5): The amount of epoxy resin contained in the adhesive composition is relatively small. This tends to slightly increase the reactivity and increase the storage modulus. Method (6): The amount of curing accelerator contained in the adhesive composition is relatively large. This tends to slightly increase the reactivity and increase the storage modulus.

[0076] The shear viscosity (melt viscosity) of the adhesive composition at 95°C is 100 to 12,000 Pa·s, and may be 200 Pa·s or more, 300 Pa·s or more, 400 Pa·s or more, or 500 Pa·s or more, or 10,000 Pa·s or less, 8,000 Pa·s or less, 7,000 Pa·s or less, 5,000 Pa·s or less, or 3,000 Pa·s or less. When the shear viscosity at 95°C is within the above range, even if the tip portion 15a of the FPC board 15 has irregularities, the adhesive composition tends to be able to be arranged without gaps between the tip portion 15a and the member to be bonded (printed circuit board 12).

[0077] The shear viscosity of an adhesive composition at 95°C can be measured, for example, by the following procedure. First, multiple film-like adhesives made from the adhesive composition are prepared, each 25 μm thick. Next, multiple film-like adhesives are laminated to a thickness of approximately 300 μm, and this laminate is punched out with a φ9 mm punch to prepare a measurement sample. An 8 mm diameter circular aluminum plate jig is installed in a dynamic viscoelasticity apparatus, and the measurement sample is set thereon. Next, measurements are performed while applying a 5% strain at 35°C and increasing the temperature to 100°C at a heating rate of 5°C / min, and the viscosity at 95°C is determined, thereby measuring the shear viscosity at 95°C. Note that during the measurement, the frequency is kept constant at 1 Hz, the initial load is maintained at 300 g, and the axial force is maintained at 100 g.

[0078] The laminate film 10 can be produced, for example, as follows. First, a coating liquid is prepared by dissolving the adhesive composition that constitutes the adhesive layer 3 in an organic solvent to form a varnish. This coating liquid is then applied to the base film 1, and the organic solvent is then removed to form the adhesive layer 3. Coating methods include knife coating, roll coating, spray coating, gravure coating, bar coating, and curtain coating. Next, a cover film 5 is laminated to the surface of the adhesive layer 3 at room temperature (25°C) to 60°C. This allows the laminate film 10 to be obtained. Alternatively, the laminate film 10 can be obtained by forming the adhesive layer 3 on a wide base film, then laminating the cover film 5 to cover it, and then cutting (slitting) the laminate film 10 to a predetermined width.

[0079] The thickness of the adhesive layer 3 may be appropriately selected within a range that does not impair workability, and may be, for example, 1 to 200 μm, 5 to 150 μm, or 10 to 150 μm. When the thickness of the adhesive layer 3 is 1 μm or more, sufficient adhesion is easily ensured, while when the thickness is 200 μm or less, the adhesive composition constituting the adhesive layer 3 tends to be easily prevented from spilling out from the base film 1 or the cover film 5.

[0080] <Cover Film> There are no particular restrictions on the cover film 5, as long as it can be easily peeled from the adhesive layer 3. Examples of the cover film 5 include polyester films such as polyethylene terephthalate film; polyolefin films such as homopolymers or copolymers, or mixtures thereof, of polytetrafluoroethylene film, polyethylene film, polypropylene film, polymethylpentene film, polyvinyl acetate film, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, and ethylene-ethyl acrylate copolymer; and plastic films such as polyvinyl chloride film and polyimide film. The cover film 5 may have a single-layer structure or a multi-layer structure.

[0081] When the cover film 5 has a multilayer structure, it may be an adhesive film, specifically, an adhesive film for dicing (manufactured by Maxell, Ltd.). The adhesive film may have an adhesive layer and a base layer. In this case, the adhesive layer may be configured to be in contact with the adhesive layer 3. The adhesive layer may be a photocurable adhesive layer or a non-photocurable adhesive layer, and the base layer may be the above-mentioned plastic film or the like.

[0082] The thickness of the cover film 5 may be appropriately selected within a range that does not impair workability, and may be, for example, 10 to 200 μm, 10 to 180 μm, or 15 to 140 μm. These thickness ranges are practically acceptable and economically effective.

[0083] <Punched Product> Figure 4 is a perspective view that schematically shows a punched product produced from laminate film 10. Figure 5 is a cross-sectional view taken along line V-V in Figure 4. The punched product 20 shown in Figures 4 and 5 comprises a strip-shaped base film 1 having a width of 100 mm or less, a plurality of adhesive pieces 3p arranged on the base film 1 in the longitudinal direction thereof (the direction of arrow X in Figure 4), and a cover film 5p that covers the upper surfaces 3f of the adhesive pieces 3p and has the same shape as the adhesive pieces 3p.

[0084] The adhesive piece 3p is suitably used for bonding a circuit member (semiconductor chip or printed circuit board) to the tip of the FPC board. The area of ​​the adhesive piece 3p in a plan view is, for example, 1 to 100 mm ２ and 3 to 50 mm ２ Or 5 to 40 mm ２ With the punched product 20, it is possible to sequentially pick up a plurality of adhesive pieces 3 p arranged in a line on the base film 1 (see FIG. 6 ), and then place each adhesive piece 3 p in a predetermined area on the circuit component, thereby efficiently bonding the circuit component and the FPC board.

[0085] The punched product 20 can be obtained, for example, through the following steps: (a) a step of preparing a laminated film 10. (b) a step of punching out the adhesive layer 3 and the cover film 5 in the laminated film 10 to obtain a plurality of adhesive pieces 3p arranged on the base film 1 in the longitudinal direction of the base film 1.

[0086] [Method of Manufacturing Connection Body (Semiconductor Module)] A method of manufacturing the module 50B (connection body) shown in FIG. 3 using the punched product 20 will be described. FIG. 6 is a cross-sectional view schematically showing how the adhesive piece 3p and the cover film 5p covering it are picked up from the base film 1. With a certain tension applied to the punched product 20, the surface of the punched product 20 facing the base film 1 is brought into contact with a wedge-shaped member 60, and the punched product 20 is moved in the direction of the arrow shown in FIG. 6. As a result, as shown in FIG. 6, the adhesive piece 3p and the front of the cover film 5p are raised above the base film 1. In this state, the adhesive piece 3p and the cover film 5p are picked up, for example, by a pickup device 65 having suction force.

[0087] Next, the adhesive piece 3p covered with the cover film 5p is placed on the surface of the printed circuit board 12 (see FIG. 7). Thereafter, the adhesive piece 3p is pre-pressurized and bonded to the printed circuit board 12. Pre-pressurization can be performed, for example, at a temperature of 60 to 85°C and a pressure of 0.1 to 2 MPa for 0.1 to 10 seconds. The pre-pressurization semi-cures the adhesive piece 3p, thereby improving its adhesive strength to the surface. Thereafter, the cover film 5p is peeled off from the adhesive piece 3p using adhesive tape or the like. This exposes the surface of the adhesive piece 3p.

[0088] The bonding of the tip 15a of the FPC board 15 to the printed circuit board 12 includes a step of pressing the tip 15a against the adhesive piece 3p and then a step of curing the adhesive piece 3p by heating. That is, first, the tip 15a of the FPC board 15 is placed on the upper surface 3f of the adhesive piece 3p, and then the tip 15a is pressed against the adhesive piece 3p. This results in a laminate including the printed circuit board 12, the FPC board 15, and the adhesive piece 3p (step (A)). The pressing can be performed, for example, at a temperature of 60 to 85°C and a pressure of 0.1 to 3 MPa for 0.1 to 10 seconds.

[0089] Next, the adhesive pieces 3p are cured. The curing can be performed, for example, at a temperature of 90 to 110°C for 30 to 240 minutes. As a result, the adhesive pieces 3p become adhesive pieces 3c made of a cured product of the adhesive composition, and the module 50A shown in FIG. 2 is obtained (step (B)). The relatively low temperature to which the module 50A is heated has the advantage of broadening the range of materials available.

[0090] Wire bonding is performed on the module 50A (step (C)). This results in the module 50B shown in FIG. 3. The semiconductor module is then completed through processes such as protecting the wires W1 and W2 of the module 50B with a resin material and heat treatment to further promote the curing reaction of the adhesive piece 3c. When manufacturing a connection body using this adhesive piece, steps (A), (B), and (C) can be performed in sequence.

[0091] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments. For example, in the above embodiments, an example was given of a case where the adhesive piece 3p made of the adhesive composition was prepared in advance by die cutting, but the adhesive layer may also be formed by preparing a coating liquid containing the adhesive composition and coating this on the surface of the printed circuit board 12.

[0092] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples.

[0093] Examples 1 to 11 and Comparative Examples 1 to 5 [Production of Laminated Film] <Preparation of Materials> In order to prepare adhesive varnishes of Examples 1 to 11 and Comparative Examples 1 to 5, the following materials were prepared. (1) Epoxy resin N-500P-10 (trade name, manufactured by DIC Corporation, cresol novolac type epoxy resin, epoxy equivalent: 204 g / eq, softening point: 84°C (solid at 25°C)) YDF-8170C (trade name, manufactured by Nippon Steel Chemical & Material Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent: 165 g / eq, liquid at 25°C) EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol F type epoxy resin, epoxy equivalent: 159 g / eq, liquid at 25°C) (2) Phenolic resin H-4 (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenylaralkyl type phenolic resin, hydroxyl group equivalent: 105 g / eq, softening point: 69°C) PSM-4326 (trade name, manufactured by Gunei Chemical Industry Co., Ltd., phenol novolac resin, hydroxyl equivalent: 105 g / eq, softening point: 120°C) HF-1M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenol novolac resin, hydroxyl equivalent: 106 g / eq, softening point: 84°C) HF-3M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenol novolac resin, hydroxyl equivalent: 107 g / eq, softening point: 96°C) MEH-7800-4S (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), xylylene phenol resin, hydroxyl equivalent: 173 g / eq, softening point: 63°C) (1) Benzene phenyl aralkyl phenol resin, hydroxyl equivalent: 174 g / eq, softening point: 82°C, manufactured by Meiwa Kasei Co., Ltd. (currently UBE Corporation), MEH-7800M (trade name, manufactured by Meiwa Kasei Co., Ltd. (currently UBE Corporation), phenyl aralkyl phenol resin, hydroxyl equivalent: 174 g / eq, softening point: 82°C) MEHC-7851SS (trade name, manufactured by Meiwa Kasei Co., Ltd. (currently UBE Corporation), biphenyl phenol novolac resin, hydroxyl equivalent: 203 g / eq, softening point: 67°C) (2) Elastomer SG-P3 solvent change product (trade name, manufactured by Nagase ChemteX Corporation, acrylic resin, weight average molecular weight: 800,000, Tg: 12°C, solid at 25°C) (3) Curing accelerator MOI-BP (trade name, manufactured by Resonac Corporation, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate, liquid at 25°C) AOI-BP (trade name, manufactured by Resonac Co., Ltd., 2-[(3,(5) Inorganic filler: SC-2050-HLG (trade name, manufactured by Admatechs Co., Ltd., surface-treated filler); (6) Coupling agent: SH6040 (trade name, 3-glycidoxypropyltrimethoxysilane, manufactured by DuPont Toray Specialty Materials Co., Ltd.); (7) Organic solvent: cyclohexanone;

[0094] The materials shown in Tables 1, 2, and 3 were mixed with an organic solvent and vacuum degassed to obtain adhesive varnishes. The numerical values ​​for each material shown in Tables 1, 2, and 3 indicate the parts by mass of solid content. This adhesive varnish was applied to a 38 μm thick, surface-release-treated PET film used as a substrate film. After a drying process, a 25 μm thick film-like adhesive (adhesive layer) was formed on one side of the PET film, and laminate films comprising a substrate film and an adhesive layer were obtained for Examples 1 to 11 and Comparative Examples 1 to 5. Multiple laminate films were prepared.

[0095] [Evaluation of Laminated Film] <Measurement of Reaction Rate> The reaction rate of the film adhesive was measured using the following method. Specifically, 10 mg of the film adhesive was weighed into an aluminum pan (manufactured by Epolead Services Co., Ltd.), an aluminum lid was placed on top, and the evaluation sample was sealed in the sample pan using a crimper. Using a differential scanning calorimeter (Thermo plus DSC8235E, manufactured by Rigaku Corporation), DSC was measured under a nitrogen atmosphere at a heating rate of 10°C / min over a measurement temperature range of 30 to 300°C. A partial area analysis method was used to analyze the calorific value. By instructing analysis in the temperature range of 50 to 200°C of the DSC curve, a baseline was specified for the analysis temperature range, and the total calorific value (unit: J / g) was calculated by integrating the peak area. This was designated the initial calorific value C1.

[0096] Next, the film-like adhesive (initial sample) was placed in an oven set to 95°C and heat-treated for 3 hours. Using the sample after heat treatment, the calorific value (unit: J / g) from 50 to 200°C was calculated using the same procedure as before heat treatment, as described above, and this was designated as the calorific value C2 after heat treatment. Using the two obtained values ​​of calorific value C1 and calorific value C2, the reaction rate was calculated using the following formula. The results are shown in Tables 1, 2, and 3. Reaction rate (%) = (C1 - C2) / C1 x 100

[0097] <Measurement of Storage Modulus> The storage modulus of the film-like adhesive after heating at 95°C for 3 hours was measured using the following method. Specifically, multiple 25 μm thick film-like adhesives were laminated to a thickness of approximately 300 μm, which was then cut into a 4 mm wide x 33 mm size and heat-treated at 95°C for 3 hours to obtain a measurement sample. The sample was placed in a dynamic viscoelasticity apparatus (product name: Rheogel E-4000, manufactured by UBM Corporation) with a chuck distance of 20 mm, and a tensile load was applied, followed by measurement at a frequency of 10 Hz and a heating rate of 3°C / min. The storage modulus at 35°C and 85°C was measured, and the ratio of the storage modulus at 35°C to the storage modulus at 85°C was calculated. The results are shown in Tables 1, 2, and 3.

[0098] <Measurement of Shear Viscosity (Melt Viscosity)> The shear viscosity of the film adhesive (in a B-stage state before heating) at 95°C was measured using the following method. Specifically, multiple 25 μm-thick film adhesives were laminated to a thickness of approximately 300 μm, and this laminate was punched out with a φ9 mm punch to prepare a sample. An 8 mm diameter circular aluminum plate was installed in an ARES dynamic viscoelasticity analyzer (manufactured by TA Instruments), and the sample was placed on the plate. The shear viscosity at 95°C was then measured while applying a 5% strain at 35°C and increasing the temperature to 100°C at a rate of 5°C / min. The frequency was constant at 1 Hz, the initial load was maintained at 300 g, and the axial force was maintained at 100 g. The results are shown in Tables 1, 2, and 3. In Examples 8 and 9, the fluidity of the samples was too high during the measurement, making it impossible to measure the shear viscosity.

[0099] <Measurement of Adhesion Strength to Polyimide Film (PI Peel Strength)> The adhesion strength of the adhesive layer of the laminate film to the polyimide film was measured using the following method. First, a cover film (a PET film with a surface release treatment) was attached to the adhesive layer of the laminate film of Examples 1 to 11 and Comparative Examples 1 to 5, and the laminate films of Examples 1 to 11 and Comparative Examples 1 to 5 were prepared, each comprising a base film, an adhesive layer, and a cover film. Next, this laminate film was punched out to a size of 3.2 mm x 3.2 mm. After peeling the base film from the laminate film, the adhesive layer was attached to an organic substrate (FPC board) and temporarily pressure-bonded for 0.5 seconds at a pressure of 1.0 N on a stage heated to 75°C. Next, the cover film was peeled from the adhesive layer, and a 5 mm x 100 mm polyimide film (UPILEX 50S (trade name), manufactured by UBE Corporation) was attached to the adhesive layer and then permanently pressure-bonded for 1 second at a force of 15 N on a stage heated to 75°C. The adhesive layer was then cured by heating at 95°C for 3 hours to obtain a measurement sample. The adhesive strength (PI peel strength) was measured at a test speed of 50 mm / min using a 90-degree peel tester (manufactured by Tester Sangyo Co., Ltd.). The results are shown in Tables 1, 2, and 3.

[0100]

[0101]

[0102]

[0103] As shown in Tables 1, 2, and 3, the adhesive compositions of Examples 1 to 11 were superior in adhesive strength to polyimide films (PI peel strength) compared to the adhesive compositions of Comparative Examples 1 to 5. These results confirmed that the thermosetting adhesive composition of the present disclosure is applicable to low-temperature curing processes and is capable of forming an adhesive layer exhibiting high adhesive strength.

[0104] 1...base film, 3...adhesive layer, 3c, 3p...adhesive pieces, 5, 5p...cover film, 10...laminated film, 12...printed circuit board, 15...FPC board, 15a...tip portion, 20...punched product, 50A, 50B...module (connector), C...semiconductor chip, W1, W2...wire

Claims

1. A thermosetting adhesive composition containing an epoxy resin, a phenolic resin, an elastomer, and a curing accelerator, which, after being heated at 95°C for 3 hours, has a reaction rate of 50% or more and a ratio of the storage modulus at 35°C to the storage modulus at 85°C of 20 or less.

2. The thermosetting adhesive composition according to claim 1, having a shear viscosity at 95°C of 100 to 12,000 Pa·s.

3. The thermosetting adhesive composition according to claim 1 or 2, which has a storage modulus of 1000 MPa or less at 35°C after being heated at 95°C for 3 hours.

4. The thermosetting adhesive composition according to claim 1 or 2, which has a storage modulus of 5 MPa or more at 85°C after being heated at 95°C for 3 hours.

5. The thermosetting adhesive composition according to claim 1 or 2, which has a storage modulus of 50 MPa or more at 85°C after being heated at 95°C for 3 hours.

6. The thermosetting adhesive composition according to claim 1 or 2, wherein the reaction rate is 85% or less.

7. The thermosetting adhesive composition according to claim 1 or 2, wherein the ratio of the storage modulus at 35°C to the storage modulus at 85°C is 6 or less.

8. The thermosetting adhesive composition according to claim 1 or 2, wherein the phenolic resin comprises a phenolic resin having a hydroxyl equivalent of 150 g / eq or less.

9. The thermosetting adhesive composition according to claim 1 or 2, wherein the phenolic resin comprises a phenolic resin having a softening point of 150°C or less.

10. The thermosetting adhesive composition according to claim 1 or 2, wherein the phenolic resin comprises a phenolic novolac resin.

11. The thermosetting adhesive composition according to claim 1 or 2, wherein the epoxy resin comprises a solid epoxy resin.

12. The thermosetting adhesive composition according to claim 1 or 2, wherein the curing accelerator is a compound that generates a heterocyclic amine compound upon heating.

13. The thermosetting adhesive composition according to claim 1 or 2, wherein, based on the total amount of the thermosetting adhesive composition, the content of the epoxy resin is 20 to 35 mass %, the content of the phenolic resin is 10 to 30 mass %, the content of the elastomer is 15 to 50 mass %, and the content of the curing accelerator is 5 to 20 mass %.

14. The thermosetting adhesive composition according to claim 1 or 2, further comprising an inorganic filler.

15. A laminated film comprising: a substrate film; and an adhesive layer provided on the surface of said substrate film, said adhesive layer being composed of the thermosetting adhesive composition according to claim 1 or 2.

16. A method for manufacturing a connection, comprising the steps of: (A) preparing a laminate comprising a first circuit member, a second circuit member, and an adhesive layer disposed between the first circuit member and the second circuit member; (B) heating the laminate at 90 to 110°C for 30 to 240 minutes; and (C) wire-bonding the first circuit member and the second circuit member, in this order; wherein the adhesive layer is composed of the thermosetting adhesive composition according to claim 1 or 2.

17. The method for producing a connection body according to claim 16, wherein the first circuit member is one selected from the group consisting of a printed circuit board and a semiconductor chip, and the second circuit member is a flexible printed circuit board.

18. A connection body comprising: a first circuit member; a second circuit member; and an adhesive layer disposed between the first circuit member and the second circuit member, wherein the adhesive layer is formed from a cured product of the thermosetting adhesive composition according to claim 1 or 2.

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