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

Abstract

The purpose of the present disclosure is to provide a thermosetting adhesive composition in which an increase over time in shear viscosity can be adequately suppressed and which can form an adhesive layer having a suitable degree of tack on a surface.　Disclosed is a thermosetting adhesive composition that contains an epoxy resin, a phenolic resin, a curing accelerator, an inorganic filler and an elastomer. The epoxy resin includes at least one type selected from the group consisting of liquid epoxy resins that are liquids at 25ºC and solid epoxy resins that are solids at 25°C. The phenolic resin includes at least one type selected from the group consisting of liquid phenolic resins that are liquids at 25ºC and solid phenolic resins that are solids at 25°C. The curing accelerator includes at least one type selected from the group consisting of liquid curing accelerators that are liquids at 25ºC and solid curing accelerators that are solids at 25°C. The total content of components that are liquids at 25°C is 5 mass% or more based on the total amount of the thermosetting adhesive composition. The content of liquid epoxy resins is 14 mass% or less based on the total amount of the thermosetting adhesive composition. The shear viscosity of the thermosetting adhesive composition at 95°C is 100-12,000 Pa·s.

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 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 undergone significant changes. For example, processes that do not involve dicing or die bonding are being put into practical use. Accordingly, different performance is being demanded of thermosetting adhesive compositions used in the manufacturing process of semiconductor modules. In addition to this situation, the inventors, anticipating the use of materials with relatively low heat resistance in semiconductor modules, have been developing a thermosetting adhesive composition that undergoes sufficient curing reaction at low temperatures of 100°C or less. While improvements were made based on a conventional thermosetting adhesive composition with excellent low-temperature curing properties, they achieved the development goal of low-temperature curing properties, but found that the shear viscosity tended to increase over time. Since an increase in shear viscosity over time limits the usable period after preparation to approximately two weeks, there is a demand for a longer usable period for thermosetting adhesive compositions. In addition, the surface of the adhesive layer formed from such a thermosetting adhesive composition is also required to have a tack (stickiness) sufficient to allow a cover film to adhere to it.

[0005] A primary object of the present disclosure is to provide a thermosetting adhesive composition that is capable of sufficiently suppressing an increase in shear viscosity over time and is capable of forming an adhesive layer having a suitable degree of tack on the surface.

[0006] In order to solve the above problems, the present inventors conducted research on thermosetting adhesive compositions and discovered that by adjusting the content of components that are liquid at 25°C in the thermosetting adhesive composition within a predetermined range, it is possible to form an adhesive layer that has appropriate tack (stickiness) while suppressing an increase in shear viscosity over time, and thus completed the invention of the present disclosure.

[0007] The present disclosure provides a thermosetting adhesive composition according to any one of items [1] to [6], a laminate film according to item [7], a method for manufacturing a connection body according to items [8] and [9], and a connection body according to item

[10] . [1] A thermosetting adhesive composition comprising an epoxy resin, a phenolic resin, a curing accelerator, an inorganic filler, and an elastomer, wherein the epoxy resin comprises at least one selected from the group consisting of a liquid epoxy resin that is liquid at 25°C and a solid epoxy resin that is solid at 25°C, the phenolic resin comprises at least one selected from the group consisting of a liquid phenolic resin that is liquid at 25°C and a solid phenolic resin that is solid at 25°C, the curing accelerator comprises at least one selected from the group consisting of a liquid curing accelerator that is liquid at 25°C and a solid curing accelerator that is solid at 25°C, the total content of components that are liquid at 25°C is 5 mass% or more based on the total amount of the thermosetting adhesive composition, the content of the liquid epoxy resin is 14 mass% or less based on the total amount of the thermosetting adhesive composition, and the thermosetting adhesive composition has a shear viscosity at 95°C of 100 to 12,000 Pa s. [2] The thermosetting adhesive composition according to [1], wherein the curing accelerator comprises a liquid curing accelerator. [3] The thermosetting adhesive composition according to [1], wherein the epoxy resin comprises a liquid epoxy resin. [4] The thermosetting adhesive composition according to any one of [1] to [3], wherein the curing accelerator is a compound that generates a heterocyclic amine compound upon heating. [5] The thermosetting adhesive composition according to [4], wherein the heterocyclic amine compound is an aromatic heterocyclic amine compound. [6] The thermosetting adhesive composition according to any one of [1] to [5], wherein the reaction rate after heating at 90°C for 3 hours is 50% or more. [7] A laminated film comprising: a substrate film; and an adhesive layer provided on a surface of the substrate film, wherein the adhesive layer is composed of the thermosetting adhesive composition according to any one of [1] to [6].[8] 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, in this order, wherein the adhesive layer is formed from the thermosetting adhesive composition described in any of [1] to [6]. [9] A method for manufacturing a connection body according to [8], 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.

[10] 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 any of [1] to [6].

[0008] According to the present disclosure, there is provided a thermosetting adhesive composition that can sufficiently suppress an increase in shear viscosity over time and can form an adhesive layer having a suitable surface tack. The present disclosure also provides an adhesive film having an adhesive layer made of such a thermosetting adhesive composition. The present disclosure also provides a connection structure using such a thermosetting adhesive composition and a method for producing 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] In this specification, "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 composition contains multiple substances corresponding to each component, the content of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified.

[0015] As used herein, "liquid at 25°C" means that the melting point or softening point is lower than 25°C, or that the viscosity measured at 25°C is lower than 3000 Pa s. "Solid at 25°C" means that the melting point or softening point is 25°C or higher, or that the viscosity measured at 25°C is 3000 Pa s or higher. The softening point refers to a value measured by the ring and ball method in accordance with JIS K7234:1986, JIS K6910:2007, etc. The viscosity measured at 25°C refers to a value measured using an E-type viscometer or a B-type viscometer for the component (compound) held at 25°C.

[0016] [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.

[0017] <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 homocopolymers 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 multi-layer structure.

[0018] 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.

[0019] 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 may 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. (now Toyobo Co., Ltd.) and A-31 (release treatment agent: Pt-based silicone-based) manufactured by Toyobo Film Solutions Co., Ltd. (now Toyobo Co., Ltd.).

[0020] 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.

[0021] 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 between the adhesive layer 3 and 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.

[0022] <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.

[0023] 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.

[0024] The adhesive piece 3p (adhesive layer) is made of a thermosetting adhesive composition (hereinafter, sometimes simply referred to as the "adhesive composition"). The adhesive composition contains an epoxy resin, a phenolic resin, a curing accelerator, an inorganic filler, and an elastomer.

[0025] Epoxy Resin The epoxy resin includes at least one selected from the group consisting of liquid epoxy resins that are liquid at 25°C and solid epoxy resins that are solid at 25°C. In one embodiment, the epoxy resin may include a liquid 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 naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and diglycidyl ethers of these alkyl-substituted, halides, and hydrogenated versions of these bifunctional epoxy resins and novolac epoxy resins. 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 included as impurities to the extent that they do not impair the properties.

[0026] Specific examples of solid epoxy resins include YDCN-700-10 (manufactured by Nippon Steel Chemical & Material Co., Ltd., cresol novolac type epoxy resin), N-500P-10 (manufactured by DIC Corporation, cresol novolac type epoxy resin), HP-4710 (manufactured by DIC Corporation, naphthalene type epoxy resin), and NC-7000L (manufactured by Nippon Kayaku Co., Ltd., naphthalene type epoxy resin).

[0027] Specific examples of liquid epoxy resins include YDF-8170C (bisphenol F type epoxy resin, manufactured by Nippon Steel Chemical & Material Co., Ltd.), EPICLON (registered trademark) series (EXA-830CRP, 830, 830-S, 835, etc.) (bisphenol F type epoxy resin, manufactured by DIC Corporation), and the like.

[0028] The content of the epoxy resin is, for example, 5 to 35 mass %, or may be 10 to 30 mass %, or 15 to 25 mass %, based on the total amount of the adhesive composition. 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.

[0029] The content of the liquid epoxy resin is 14% by mass or less, based on the total amount of the adhesive composition. When the content of the liquid epoxy resin is within the above range, it is possible to sufficiently suppress an increase in shear viscosity over time. The content of the liquid epoxy resin may be, for example, 12% by mass or less, 10% by mass or less, 8% by mass or less, 6% by mass or less, 4% by mass or less, or 2% by mass or less, based on the total amount of the adhesive composition, or may be 0% by mass or more, 2% by mass or more, 4% by mass or more, 6% by mass or more, or 8% by mass or more. The content of the liquid epoxy resin may even be 0% by mass, based on the total amount of the adhesive composition.

[0030] Phenolic Resin The phenolic resin includes at least one selected from the group consisting of liquid phenolic resins that are liquid at 25° C. and solid phenolic resins that are solid at 25° C. In one embodiment, the phenolic resin may include a solid phenolic resin. The phenolic resin is not particularly limited as long as it has a phenolic hydroxyl group in the molecule. Examples of phenolic resins include novolak-type phenolic 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; phenol aralkyl resins, naphthol aralkyl resins, biphenyl aralkyl-type phenolic resins, and phenyl aralkyl-type phenolic resins synthesized from phenols such as phenol and / or naphthols with dimethoxyparaxylene or bis(methoxymethyl)biphenyl;

[0031] Specific examples of solid phenolic resins include PSM-4326 (phenol novolac type phenolic resin, manufactured by Gunei Chemical Industry Co., Ltd.) and MEH-7800M (phenylaralkyl type phenolic resin, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation)).

[0032] A specific example of the liquid phenolic resin is MEH-8000H (phenol novolac type phenolic resin, manufactured by Meiwa Kasei Co., Ltd. (currently UBE Corporation)).

[0033] The content of the phenolic resin is, for example, 5 to 35 mass %, or may be 10 to 30 mass %, or 15 to 25 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.

[0034] The total content of the epoxy resin and the phenolic resin is, for example, 30 to 60 mass %, or may be 40 to 50 mass %, or 35 to 45 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.

[0035] Curing Accelerator The curing accelerator includes 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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, 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.

[0040] 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.

[0041] 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.

[0042] Examples of the second compound include pyrazonium salt compounds, imidazolium salt compounds, etc. A specific example of the second compound is 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).

[0043] The content of the curing accelerator is, for example, 3 to 25 mass %, or may be 5 to 20 mass %, or 8 to 18 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 exhibited sufficiently.

[0044] The content of the liquid curing accelerator is, for example, 10 to 25 mass %, or may be 12 to 20 mass %, or 14 to 18 mass %, based on the total amount of the adhesive composition. When the content of the liquid curing accelerator is within the above range, it tends to be possible to sufficiently suppress an increase in shear viscosity over time.

[0045] 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.

[0046] 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.

[0047]

[0048] 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, an isocyanate group, and a methacryloxy group; s represents 0 or an integer of 1 to 10; R１１ , R １２ , and R １３ each independently represents an alkyl group having 1 to 10 carbon atoms.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The content of the inorganic filler is, for example, 0 to 50% by mass, or may be 10 to 40% by mass, or 20 to 30% by mass, based on the total amount of the adhesive composition. When the content of the inorganic filler is 50% 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.

[0053] Elastomer: As the elastomer, a resin having thermoplasticity, or a resin having thermoplasticity at least in an uncured state and forming 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.

[0054] When the adhesive composition contains a reactive group-containing (meth)acrylic copolymer as the elastomer, the adhesive composition may be in an embodiment that does not contain an epoxy resin, i.e., the adhesive composition may be in an embodiment that contains a reactive group-containing (meth)acrylic copolymer and a curing accelerator.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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 0°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.

[0061] 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.

[0062] 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.

[0063] The content of the elastomer is, for example, 5 to 45 mass %, or may be 10 to 35 mass %, or 15 to 25 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.

[0064] The total content of components that are liquid at 25°C is 5% by mass or more, based on the total amount of the adhesive composition. Examples of components that are liquid at 25°C include liquid epoxy resins, liquid phenolic resins, liquid curing accelerators, and liquid elastomers. The components that are liquid at 25°C may be, for example, liquid epoxy resins, liquid phenolic resins, and liquid curing accelerators, or may be liquid epoxy resins and liquid curing accelerators. When the total content of components that are liquid at 25°C is within the above range, it is possible to form an adhesive layer with appropriate tackiness on the surface. The total content of components that are liquid at 25°C may be, for example, 8% by mass or more, 10% by mass or more, 12% by mass or more, or 14% by mass or more, based on the total amount of the adhesive composition, and may be 25% by mass or less, 22% by mass or less, 20% by mass or less, 18% by mass or less, 16% by mass or less, 14% by mass or less, or 12% by mass or less.

[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 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, 6,000 Pa·s or less, or 4,000 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).

[0068] 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.

[0069] The following methods can be considered to adjust the shear viscosity at 95°C to a predetermined range, for example: Method 1: The amount of inorganic filler contained in the adhesive composition is made relatively small. Method 2: The amount of elastomer (e.g., acrylic rubber) contained in the adhesive composition is made relatively small. Method 3: The average particle size of the inorganic filler contained in the adhesive composition is made relatively large.

[0070] It is preferable that the adhesive composition undergoes a curing reaction to some extent after heat treatment at 90°C for 3 hours. The extent to which the reaction has progressed 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, for example, 50% or more, and may also be 60% or more, 70% or more, or 80% or more. Reaction rate (%) = (C1 - C2) / C1 × 100

[0071] 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 90°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. A reaction rate of 50% or more can suppress deterioration over time after the manufacturing process, and tends to result in excellent reliability.

[0072] 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 a solvent such as an organic solvent to form a varnish. This coating liquid is then applied to the base film 1, and the 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.

[0073] 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.

[0074] <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 homocopolymers 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.

[0075] 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.

[0076] 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.

[0077] <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.

[0078] 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 member, thereby efficiently bonding the circuit member and the FPC member.

[0079] 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.

[0080] [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.

[0081] Next, the adhesive piece 3p covered with the cover film 5p is placed on the surface 12a of the printed circuit board 12 (see FIG. 7). Thereafter, the adhesive piece 3p is pre-pressurized 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 12a. Thereafter, the cover film 5p is peeled off from the adhesive piece 3p using adhesive tape or the like. This exposes the surface F1 of the adhesive piece 3p.

[0082] 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.

[0083] 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.

[0084] 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 heating the adhesive piece 3c to promote a curing reaction. When manufacturing a connection body using this adhesive piece, steps (A), (B), and (C) can be performed in sequence.

[0085] 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.

[0086] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples.

[0087] Examples 1 to 4 and Comparative Examples 1 and 2 [Production of Laminated Film] <Preparation of Materials> In order to prepare adhesive varnishes for Examples 1 to 4 and Comparative Examples 1 and 2, the following materials were prepared. (1) Epoxy Resin EXA-830CRP (trade name, manufactured by DIC Corporation, bisphenol F type epoxy resin, epoxy equivalent: 160 g / eq, liquid at 25°C) 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) (2) Phenolic Resin MEH-7800M (trade name, manufactured by Meiwa Kasei Co., Ltd. (now UBE Corporation), phenylaralkyl type phenolic resin, hydroxyl group equivalent: 174 g / eq, softening point: 82°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 Corporation, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl acrylate, solid at 25°C) (4) Inorganic filler SC-2050-HLG (trade name, manufactured by Admatechs Corporation, surface-treated filler) (5) Elastomer SG-P3 solvent change product (trade name, manufactured by Nagase ChemteX Corporation, reactive group-containing (meth)acrylic copolymer, weight-average molecular weight: 800,000, Tg: 12°C, solid at 25°C) (6) Solvent Cyclohexanone

[0088] An adhesive varnish was obtained by mixing the materials and solvent shown in Table 1 and vacuum degassing the mixture. This adhesive varnish was applied to a 38 μm thick surface-release-treated PET film as a base 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 base film and an adhesive layer were obtained for Examples 1 to 4 and Comparative Examples 1 and 2. Multiple laminate films were prepared.

[0089] [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.

[0090] Next, the film-like adhesive (initial sample) was placed in an oven set to 90°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 Table 1. Reaction rate (%) = (C1 - C2) / C1 x 100

[0091] <Evaluation of Adhesion of Polyethylene (PE) Film> A 15 to 30 μm thick PE film was attached to the surface of the adhesive layer of the film-like adhesive at 20 to 30° C. If the PE film was attached to the adhesive layer, the adhesion of the PE film to the adhesive layer was deemed good and rated as "A," and if the PE film was not attached to the adhesive layer, it was rated as "B." The results are shown in Table 1.

[0092] <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 kept 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 Table 1. Measurement conditions: Disc plate: Aluminum, circular (8 mm diameter) Measurement frequency: 1 Hz Heating rate: 5°C / min Strain: 5% Measurement temperature: 35-100°C Initial load: 300 g Axial force: 100 g

[0093] <Evaluation of storage stability (change in shear viscosity over time)> The storage stability (change in shear viscosity over time) of the film adhesive was evaluated. The evaluation was performed by leaving the film adhesive at room temperature (25°C) and measuring the shear viscosity of the film adhesive at 95°C after leaving it under the same conditions as above. The leaving period was 3 or 4 weeks, and the shear viscosity of the film adhesive at 95°C after 3 or 4 weeks was measured. The results are shown in Table 1.

[0094]

[0095] As shown in Table 1, the reaction rate results for the adhesive compositions of Examples 1 to 4 demonstrated that the curing reaction proceeded sufficiently at low temperatures of 100°C or less. Furthermore, as shown in Table 1, the adhesive compositions of Examples 1 to 4 exhibited excellent adhesion to PE films and suppressed a significant increase in shear viscosity even after three weeks. In contrast, the adhesive composition of Comparative Example 1, in which the liquid epoxy resin content exceeded 14% by mass, based on the total amount of the thermosetting adhesive composition, exhibited a significant increase in shear viscosity after three and four weeks. Furthermore, the adhesive composition of Comparative Example 2, in which the total content of components that are liquid at 25°C was less than 5% by mass, based on the total amount of the thermosetting adhesive composition, did not exhibit sufficient adhesion to PE films. These results confirmed that the thermosetting adhesive compositions of the present disclosure are capable of sufficiently suppressing an increase in shear viscosity over time and are capable of forming an adhesive layer with appropriate surface tack.

[0096] 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, a curing accelerator, an inorganic filler, and an elastomer, wherein the epoxy resin comprises at least one selected from the group consisting of liquid epoxy resins that are liquid at 25°C and solid epoxy resins that are solid at 25°C, the phenolic resin comprises at least one selected from the group consisting of liquid phenolic resins that are liquid at 25°C and solid phenolic resins that are solid at 25°C, the curing accelerator comprises 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, the total content of components that are liquid at 25°C is 5 mass% or more based on the total amount of the thermosetting adhesive composition, the content of the liquid epoxy resin is 14 mass% or less based on the total amount of the thermosetting adhesive composition, and the thermosetting adhesive composition has a shear viscosity at 95°C of 100 to 12,000 Pa s.

2. The thermosetting adhesive composition according to claim 1, wherein the curing accelerator comprises a liquid curing accelerator.

3. The thermosetting adhesive composition according to claim 1, wherein the epoxy resin comprises a liquid epoxy resin.

4. The thermosetting adhesive composition according to any one of claims 1 to 3, wherein the curing accelerator is a compound that generates a heterocyclic amine compound upon heating.

5. The thermosetting adhesive composition according to claim 4, wherein the heterocyclic amine compound is an aromatic heterocyclic amine compound.

6. The thermosetting adhesive composition according to any one of claims 1 to 3, which has a reaction rate of 50% or more after being heated at 90°C for 3 hours.

7. A laminated film comprising: a substrate film; and an adhesive layer provided on the surface of said substrate film, said adhesive layer being formed from the thermosetting adhesive composition according to any one of claims 1 to 3.

8. 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 described in any one of claims 1 to 3.

9. The method for producing a connection body according to claim 8, 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.

10. 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 any one of claims 1 to 3.

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