Adhesive composition, adhesive film for circuit connection, connected structure, and method for producing connected structure

Abstract

An adhesive composition comprising a cationically polymerizable compound and a curing agent, wherein the curing agent is a salt of a nitrogen-containing cation with an anion represented by general formula (1). [In formula (1), R1 represents a fluoroalkyl group, a fluoroaryl group, or a fluoroalkyl-substituted aryl group, m is 0 or 1, and n is an integer of 1-4.]

Description

Adhesive composition, adhesive film for circuit connection, connection structure, and method for producing the connection structure

[0001] The present disclosure relates to an adhesive composition, an adhesive film for circuit connection (an anisotropically conductive adhesive film or a conductive adhesive film), a connection structure, and a method for producing the connection structure.

[0002] Conventionally, adhesive films have been used to electrically connect electrodes in the pressure direction by heating and pressurizing opposing circuit components. Known examples of adhesive films for circuit connection include adhesive films for circuit connection in which conductive particles are dispersed in the adhesive (see, for example, Patent Documents 1 to 4 listed below).

[0003] JP 60-191228 A JP 1-251787 A JP 7-90237 A JP 2019-104869

[0004] In recent years, the market has been demanding higher levels of quality reliability in fields such as semiconductors and liquid crystal displays, etc. Accordingly, excellent properties are also being demanded of adhesive films for circuit connection, which are used for fixing electronic components, connecting circuits, etc.

[0005] An object of the present disclosure is to provide an adhesive composition that can provide an adhesive film for circuit connection having properties superior to conventional adhesive compositions, and to provide an adhesive film for circuit connection, a connection structure, and a method for producing a connection structure that use the adhesive composition.

[0006] The present disclosure includes the following items [1] to

[16] : [1] An adhesive composition comprising a cationically polymerizable compound and a curing agent, wherein the curing agent is a salt of a nitrogen-containing cation and an anion represented by the following general formula (1): [In formula (1), R １represents a fluoroalkyl group, a fluoroaryl group, or a fluoroalkyl-substituted aryl group, m represents 0 or 1, and n represents an integer of 1 to 4.] [2] The adhesive composition according to [1], wherein the nitrogen-containing cation is an ammonium cation, an anilinium cation, or a pyridinium cation. [3] The adhesive composition according to [1] or [2], wherein the content of the curing agent is more than 5 parts by mass and not more than 40 parts by mass, based on 100 parts by mass of the cationically polymerizable compound. [4] The adhesive composition according to any one of [1] to [3], further containing conductive particles. [5] The adhesive composition according to [4], wherein the content of the curing agent is 5 to 30 parts by mass, based on 100 parts by mass of the conductive particles. [6] The adhesive composition according to any one of [1] to [5], further containing an amide having a lactam ring. [7] The adhesive composition according to [6], wherein the content of the curing agent is 1 to 20 parts by mass, based on 0.01 parts by mass of the amide having a lactam ring. [8] The adhesive composition according to any one of [1] to [7], wherein the cationically polymerizable compound comprises an epoxy compound. [9] The adhesive composition according to any one of [1] to [8], wherein, when differential scanning calorimetry (DSC) is performed under conditions of a nitrogen atmosphere, a heating rate of 10°C / min, and a measurement temperature range of 40 to 300°C, a plurality of endothermic peaks are observed, and the ratio (first peak / second peak) of the first endothermic peak to the second endothermic peak is 3 or more, or a single endothermic peak is observed.

[10] The adhesive composition according to any one of [1] to [9], wherein the reaction rate is 10% or less when heat-treated at 40°C for 15 hours.

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

[10] , wherein the reaction product obtained by heating at 180°C for 1 hour has an elastic modulus of 0.100 GPa or more at a measurement temperature of 300°C.

[12] An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to any one of [1] to

[11] .

[13] An adhesive film for circuit connection comprising an adhesive layer formed from the adhesive composition according to [4] or [5], wherein the conductive particles are arranged in a predetermined pattern when viewed in plan of the adhesive film for circuit connection.

[14] An adhesive film for circuit connection, comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, wherein at least one of the first adhesive layer and the second adhesive layer is a layer formed from the adhesive composition described in any one of [1] to

[11] .

[15] A connection structure, comprising a first circuit member having a first electrode, a second circuit member having a second electrode, and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode, wherein the connection portion comprises a cured product of the adhesive film for circuit connection described in any one of

[12] to

[14] .

[16] A method for producing a connection structure, comprising the steps of: interposing the adhesive film for circuit connection described in any one of

[12] to

[14] between a first circuit member having a first electrode and a second circuit member having a second electrode; and thermocompression-bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other.

[0007] According to the present disclosure, it is possible to provide an adhesive composition that can provide an adhesive film for circuit connection having better properties than conventional ones. Furthermore, according to the present disclosure, it is possible to provide an adhesive film for circuit connection, a connection structure, and a method for producing a connection structure that use the adhesive composition.

[0008] Fig. 4 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection. Fig. 5 is a schematic cross-sectional view showing an embodiment of an adhesive film for circuit connection. Fig. 6 is a schematic cross-sectional view showing an embodiment of a connection structure. Fig. 7 is a schematic cross-sectional view showing a method for manufacturing the connection structure of Fig. 3.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0010] In the numerical ranges described herein, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. Furthermore, the lower and upper limits of a numerical range can be arbitrarily combined with the lower or upper limit of another numerical range. When a numerical range is described as "A to B," the values ​​A and B at both ends are included as the lower and upper limits of the numerical range, respectively. In this specification, for example, "10 or more" means 10 and a value greater than 10, and this also applies when the numerical values ​​differ. Furthermore, for example, "10 or less" means 10 and a value less than 10, and this also applies when the numerical values ​​differ. Furthermore, unless otherwise specified, each component and material exemplified herein may be used alone or in combination of two or more types. In this specification, when multiple substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified. In addition, in this specification, the term "(meth)acrylate" means at least one of an acrylate and its corresponding methacrylate.

[0011] <Adhesive Composition> One embodiment of the present disclosure is an adhesive composition containing a cationically polymerizable compound and a curing agent, wherein the curing agent is a salt of a nitrogen-containing cation and an anion represented by the following general formula (1). Hereinafter, the curing agent that is a salt of a nitrogen-containing cation and an anion represented by the following general formula (1) will be referred to as curing agent A. According to the adhesive composition of one embodiment, an adhesive film for circuit connection having better properties (e.g., corrosion resistance, heat resistance) than conventional ones can be obtained. [In formula (1), R １ represents a fluoroalkyl group, a fluoroaryl group, or a fluoroalkyl-substituted aryl group, m represents 0 or 1, and n represents an integer of 1 to 4.

[0012] [Cationically polymerizable compound] The cationically polymerizable compound may be, for example, a compound that reacts with the curing agent A by heating to form a crosslink. Examples of the cationically polymerizable compound include an epoxy compound, a vinyl ether compound, and an oxetane compound. The cationically polymerizable compound may contain an epoxy compound. One type of cationically polymerizable compound may be used alone, or two or more types may be used in combination. The cationically polymerizable compound may not contain a vinyl ether compound. The cationically polymerizable compound may not contain an oxetane compound.

[0013] Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol S type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, tetramethyl bisphenol A type epoxy resin, 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (bi-7-oxabicyclo[4,1,0]heptane), 3,4-epoxycyclohexylmethyl (meth)acrylate, (3,3',4,4'-diepoxy)bicyclohexyl, dicyclopentadiene dimethanol diglycidyl ether, xylene novolac type glycidyl ether, and biphenyl type epoxy resin. The epoxy compound may contain at least one selected from the group consisting of bisphenol A type epoxy resin, tetramethyl bisphenol A type epoxy resin, dicyclopentadiene dimethanol diglycidyl ether, xylene-novolac type glycidyl ether, and alicyclic epoxy resin. The epoxy compound may contain a glycidyl ether compound. From the viewpoint of achieving better low-temperature curing properties, storage stability, and connection resistance, the epoxy compound may contain an alicyclic epoxy resin. The epoxy compound does not have to contain an alicyclic epoxy resin.

[0014] The epoxy compound may be a multifunctional epoxy resin from the viewpoint of realizing better low-temperature curing property, storage stability, and connection resistance. The number of epoxy groups in the epoxy compound may be 1 or more, 2 or more, or 3 or more, and may be 15 or less, 12 or less, or 10 or less.

[0015] The epoxy equivalent of the epoxy compound may be 100 to 300 g / eq, or 150 to 250 g / eq, from the viewpoint of achieving better low-temperature curing properties, storage stability, and connection resistance. The epoxy equivalent means a value measured in accordance with JIS K7236.

[0016] The oxetane compound can be any compound having one or more oxetane ring structures in the molecule without any particular limitation. The cationically polymerizable compound may contain an oxetane compound from the viewpoint of achieving better low-temperature curing properties, storage stability, and connection resistance. The cationically polymerizable compound may contain only one of an epoxy compound and an oxetane compound from the viewpoint of achieving better low-temperature curing properties, storage stability, and connection resistance. The case where only one of an epoxy compound and an oxetane compound is contained includes the case where one selected from an epoxy compound and an oxetane compound is used alone as the cationically polymerizable compound, and the case where one selected from an epoxy compound and an oxetane compound is used in combination with a cationically polymerizable compound such as a vinyl ether compound. The cationically polymerizable compound may contain an epoxy compound and an oxetane compound.

[0017] The content of the cationically polymerizable compound may be 10% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, based on the total mass of the adhesive composition, from the viewpoint of ensuring the curability of the adhesive composition. The content of the cationically polymerizable compound may be 70% by mass or less, 65% by mass or less, or 50% by mass or less, based on the total mass of the adhesive composition, from the viewpoint of ensuring the formability of the adhesive composition. From these viewpoints, the content of the cationically polymerizable compound may be 10 to 70% by mass, based on the total mass of the adhesive composition.

[0018] The content of the epoxy compound in the cationically polymerizable compound may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, and may be 100% by mass or less, 95% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less.

[0019] The content of the oxetane compound in the cationically polymerizable compound may be 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more, or may be 100% by mass or less, 95% by mass or less, 80% by mass or less, 70% by mass or less, 60% by mass or less, or 50% by mass or less.

[0020] [Curing agent A] Curing agent A is a salt of a nitrogen-containing cation and an anion represented by the following general formula (1): By including curing agent A in the adhesive composition, it is possible to obtain an adhesive film for circuit connection having better properties (e.g., corrosion resistance, heat resistance) than conventional adhesive compositions. [In formula (1), R １ represents a fluoroalkyl group, a fluoroaryl group, or a fluoroalkyl-substituted aryl group, m represents 0 or 1, and n represents an integer of 1 to 4.

[0021] The present inventors speculate that the reason why an adhesive film for circuit connection having better properties (e.g., corrosion resistance, heat resistance) than conventional adhesive films can be obtained by including a cationically polymerizable compound and curing agent A in the adhesive composition is as follows: The inclusion of curing agent A accelerates the polymerization reaction compared to conventional curing agents, thereby improving physical properties such as crosslink density. This makes it possible to suppress the intrusion of water and the like into the connection structure, and to obtain an adhesive film for circuit connection having better properties (e.g., corrosion resistance, heat resistance) than conventional adhesive films.

[0022] In formula (1), the fluoroalkyl group may be a perfluoroalkyl group from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance. The number of carbon atoms in the fluoroalkyl group may be 5 or less, 4 or less, 3 or less, or 2 or less from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance, and from the same viewpoint, may be 1 or more, or 2 or more.

[0023] In formula (1), examples of the aryl group of the fluoroaryl group include a phenyl group, a naphthyl group, etc. The fluoroaryl group may be a perfluoroaryl group from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0024] In formula (1), the fluoroalkyl-substituted aryl group is an aryl group having a fluoroalkyl group. The fluoroalkyl-substituted aryl group may be a perfluoroalkyl-substituted aryl group from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0025] The number of carbon atoms in the alkyl group in the fluoroalkyl-substituted aryl group may be 5 or less, 4 or less, or 3 or less, or 1 or more, or 2 or more. The aryl group in the fluoroalkyl-substituted aryl group may be a phenyl group or a naphthyl group. The number of fluoroalkyl groups in the fluoroalkyl-substituted aryl group may be 5 or less, 4 or less, 3 or less, or 2 or more, or more, or 2 or more, from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0026] In formula (1), n ​​may be 2 to 4, 3 to 4, or 4, from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0027] Examples of the anion represented by formula (1) include tetrakis[fluorophenyl]gallates such as tetrafluorogallate anion and tetrakis(pentafluorophenyl)gallate anion; tetrakis[fluorophenyl]gallates such as tetrakis(4-fluorophenyl)gallate anion; tetrakis[difluorophenyl]gallates such as tetrakis(3,5-difluorophenyl)gallate anion; tris(pentafluorophenyl)fluorogallate anion, bis(pentafluorophenyl)difluorogallate anion, (pentafluorophenyl)trifluorogallate anion; tetrakis(fluoroalkylphenyl)gallates such as tetrakis[4-(trifluoromethyl)phenyl]gallate anion; tetrakis[bis(fluoroalkyl)phenyl]gallates such as tetrakis[3,5-bis(trifluoromethyl)phenyl]gallate anion; tris[4-(trifluoromethyl)phenyl]fluorogallates tris[bis(fluoroalkyl)phenyl]fluorogallate anions such as tris[3,5-bis(trifluoromethyl)phenyl]fluorogallate anion; bis[(fluoroalkyl)phenyl]difluorogallate anions such as bis[4-(trifluoromethyl)phenyl]difluorogallate anion; bis[bis(fluoroalkyl)phenyl]difluorodifluorogallate anions such as bis[3,5-bis(trifluoromethyl)phenyl]difluorogallate anion; [(fluoroalkyl)phenyl]trifluorogallate anions such as [4-(trifluoromethyl)phenyl]trifluorogallate anion; [bis(fluoroalkyl)phenyl]trifluorogallate anions such as [3,5-bis(trifluoromethyl)phenyl]trifluorogallate anion; and [bis(fluoroalkyl)phenyl]trifluorogallate anions such as [3,5-bis(trifluoromethyl)phenyl]trifluorogallate anion. The anion represented by formula (1) may be a tetrakis(pentafluorophenyl)gallate anion, from the viewpoint of achieving better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0028] The nitrogen-containing cation may be, for example, an ammonium cation, an anilinium cation, or a pyridinium cation, from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance. The nitrogen-containing cation may be, for example, an anilinium cation, from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0029] The nitrogen-containing cation may be, for example, a cation represented by the following general formula (2), from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance. [In formula (2), R ２１ , R ２２ , and R ２３ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted heterocyclic group.]

[0030] In formula (2), examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an aralkyl group. Examples of the aralkyl group include a phenylmethyl group, a phenylethyl group, a naphthylmethyl group, and a cinnamyl group. These alkyl groups may have a substituent.

[0031] In formula (2), examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, etc. These aryl groups may have a substituent.

[0032] In formula (2), examples of the alkenyl group include a propenyl group, a 2-butenyl group, a 2-pentanyl group, a 2-hexanyl group, etc. These alkenyl groups may have a substituent.

[0033] In the formula (2), examples of the alkoxyl group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. These alkoxyl groups may have a substituent.

[0034] In formula (2), examples of the aryloxy group include a 4-phenylmethoxy group, a 4-phenylethoxy group, a 4-phenyloxycarbonylmethyl group, etc. These aryloxy groups may have a substituent.

[0035] In formula (2), examples of the heterocyclic group include a pyridinyl group, a 4-cyclohexaneoxide group, etc. These heterocyclic groups may have a substituent.

[0036] Examples of the substituent in the alkyl group or the like in formula (2) include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, and hexyl group; aryl groups such as phenyl group and naphthyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group, and butoxy group; alkoxycarbonyl groups such as acetoxy group, propionyloxy group, decylcarbonyloxy group, and dodecylcarbonyloxy group; ester groups such as methoxycarbonyl group, ethoxycarbonyl group, and benzoyloxy group; phenylthio group; halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom; cyano group; nitro group; and hydroxy group.

[0037] In formula (2), the benzene ring bonded to the nitrogen atom may have a substituent, or may not have a substituent from the viewpoint of realizing better low-temperature curing property, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0038] From the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance, R ２１ , R ２２ , and R ２３ may each independently be a substituted or unsubstituted alkyl group, R ２１ , R ２２ , and R ２３ At least one of R may be an aralkyl group. ２１ , R ２２ , and R ２３ At least one of the groups may be a benzyl group, from the viewpoint of achieving better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0039] The nitrogen-containing cation is a cation containing at least a nitrogen atom. From the viewpoint of realizing better low-temperature curing property, storage stability, corrosion resistance, heat resistance, and connection resistance, the nitrogen-containing cation may be a cation represented by the following general formula (3): [In formula (3), R ３１ , and R ３３ each independently represents a substituted or unsubstituted alkyl group; R ３２ represents a substituted or unsubstituted alkylene group, R ３４ represents an electron-donating group.

[0040] R ３１ , and R ３３ R may each be an unsubstituted alkyl group from the viewpoint of realizing better low-temperature curing property, storage stability, corrosion resistance, heat resistance, and connection resistance. ３１ , and R ３３ may each be a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, or an aralkyl group, and may each be a methyl group from the viewpoint of achieving better low-temperature curing property, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0041] R ３２ R may each be an unsubstituted alkylene group from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance. ３２ may be a methylene group, an ethylene group, a propylene group, an isopropylene group, a butylene group, or an isobutylene group, and may be a methylene group from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0042] Electron-donating group (R ３４ Examples of the electron-withdrawing group (R) include an alkyl group, an alkoxy group, a hydroxyl group, an amino group, and an alkylamino group. Examples of the alkyl group include a methyl group, an ethyl group, a normal propyl group, and an isopropyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. ３４From the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance, R may be an alkyl group or an alkoxy group, or may be a methyl group or a methoxy group. ３４ The benzene ring to which R is attached may contain multiple electron donating groups. ３４ The number of electron-donating groups possessed by the benzyl group to which R is bonded may be 3 or less, 2 or less, or 1, from the viewpoint of realizing better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance. ３４ The benzyl group to which R is bonded is preferably at the 4-position (R ３４ R of the benzyl group to which ３２ The fourth position when the bonding position with R is the first position. ３４ R of the benzyl group to which ３２ The aryl group may have at least one electron-donating group at a position (para to the position of bonding with the aryl group).

[0043] In formula (3), the benzene ring bonded to the nitrogen atom may have a substituent, or may not have a substituent from the viewpoint of realizing better low-temperature curing property, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0044] Examples of the cation represented by formula (3) include a (4-methylbenzyl)dimethylanilinium cation, a (4-methoxybenzyl)dimethylanilinium cation, a (4-hydroxybenzyl)dimethylanilinium cation, a (4-aminobenzyl)dimethylanilinium cation, a (4-ethylbenzyl)dimethylanilinium cation, a (4-ethoxybenzyl)dimethylanilinium cation, a (4-methylbenzyl)methylethylanilinium cation, a (4-methoxybenzyl)methylethylanilinium cation, a (4-hydroxybenzyl)methylethylanilinium cation, a (4-aminobenzyl)methylethylanilinium cation, a (4-methylbenzyl)diethylanilinium cation, a (4-methoxybenzyl)diethylanilinium cation, a (4-hydroxybenzyl)diethylanilinium cation, and a (4-aminobenzyl)diethylanilinium cation. The cation represented by formula (3) may be a (4-methylbenzyl)dimethylanilinium cation, from the viewpoint of achieving better low-temperature curing properties, storage stability, corrosion resistance, heat resistance, and connection resistance.

[0045] The content of curing agent A in the adhesive composition may be 1% by mass or more, 2% by mass or more, or 3% by mass or more, based on the total mass of the adhesive composition, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive composition may be 20% by mass or less, 17% by mass or less, or 15% by mass or less, based on the total mass of the adhesive composition, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 1 to 20% by mass, 3 to 17% by mass, or 5 to 15% by mass, based on the total mass of the adhesive composition. The content of curing agent A in the adhesive composition may be 4% by mass or more, 4.5% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition, and may be 13% by mass or less, 11% by mass or less, 9% by mass or less, 7% by mass or less, or 5% by mass or less.

[0046] The content of curing agent A in the adhesive composition may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition excluding the conductive particles, from the viewpoint of sufficiently accelerating the curing reaction. The content of curing agent A in the adhesive composition may be 20% by mass or less, 17% by mass or less, or 15% by mass or less, based on the total mass of the adhesive composition excluding the conductive particles, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 1 to 20% by mass, 3 to 17% by mass, or 5 to 15% by mass, based on the total mass of the adhesive composition excluding the conductive particles. The content of curing agent A in the adhesive composition may be 4% by mass or more, 4.5% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition excluding the conductive particles, and may be 13% by mass or less, 11% by mass or less, 9% by mass or less, 7% by mass or less, or 5% by mass or less.

[0047] The content of curing agent A in the adhesive composition may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive composition excluding the conductive particles and filler, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive composition may be 30% by mass or less, 27% by mass or less, 25% by mass or less, 22% by mass or less, or 20% by mass or less, based on the total mass of the adhesive composition excluding the conductive particles and filler, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 1 to 30% by mass, 3 to 27% by mass, or 5 to 20% by mass, based on the total mass of the adhesive composition excluding the conductive particles and filler. The content of curing agent A in the adhesive composition may be 6% by mass or more, 7% by mass or more, or 7.5% by mass or more, based on the total mass of the adhesive composition excluding the conductive particles and the filler, and may be 18% by mass or less, 16% by mass or less, 14% by mass or less, 12% by mass or less, 10% by mass or less, or 8% by mass or less.

[0048] The content of curing agent A in the adhesive composition may be 3 parts by mass or more, 5 parts by mass or more, 7 parts by mass or more, or 10 parts by mass or more, based on 100 parts by mass of the cationically polymerizable compound, from the viewpoint of sufficiently accelerating the curing reaction. The content of curing agent A in the adhesive composition may be 40 parts by mass or less, 37 parts by mass or less, 34 parts by mass or less, 31 parts by mass or less, 28 parts by mass or less, 25 parts by mass or less, 22 parts by mass or less, or 20 parts by mass or less, based on 100 parts by mass of the cationically polymerizable compound, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 3 to 40 parts by mass, more than 3 parts by mass and 40 parts by mass or less, more than 5 parts by mass and 40 parts by mass or less, 5 to 37 parts by mass, or 10 to 20 parts by mass, based on 100 parts by mass of the cationically polymerizable compound. The content of curing agent A in the adhesive composition may be 11 parts by mass or more, 12 parts by mass or more, 13 parts by mass or more, or 14 parts by mass or more, and may be 18 parts by mass or less, 17 parts by mass or less, 16 parts by mass or less, or 15 parts by mass or less, based on 100 parts by mass of the cationically polymerizable compound.

[0049] When the adhesive composition contains an epoxy compound, the content of curing agent A in the adhesive composition may be 3 parts by mass or more, 5 parts by mass or more, 7 parts by mass or more, or 10 parts by mass or more, based on 100 parts by mass of the epoxy compound, from the viewpoint of sufficiently accelerating the curing reaction. The content of curing agent A in the adhesive composition may be 40 parts by mass or less, 37 parts by mass or less, 34 parts by mass or less, 31 parts by mass or less, 28 parts by mass or less, 25 parts by mass or less, 22 parts by mass or less, or 20 parts by mass or less, based on 100 parts by mass of the epoxy compound, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 3 to 40 parts by mass, 5 to 37 parts by mass, or 10 to 20 parts by mass, based on 100 parts by mass of the epoxy compound. The content of curing agent A in the adhesive composition may be 11 parts by mass or more, 12 parts by mass or more, 13 parts by mass or more, or 14 parts by mass or more, and may be 18 parts by mass or less, 17 parts by mass or less, 16 parts by mass or less, or 15 parts by mass or less, based on 100 parts by mass of the epoxy compound.

[0050] When the adhesive composition contains an oxetane compound, the content of curing agent A in the adhesive composition may be 3 parts by mass or more, 5 parts by mass or more, 7 parts by mass or more, or 10 parts by mass or more, based on 100 parts by mass of the oxetane compound, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive composition may be 40 parts by mass or less, 37 parts by mass or less, 34 parts by mass or less, 31 parts by mass or less, 28 parts by mass or less, 25% by mass or less, 22% by mass or less, or 20 parts by mass or less, based on 100 parts by mass of the oxetane compound, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive composition may be 3 to 40 parts by mass, 5 to 37 parts by mass, or 10 to 20 parts by mass, based on 100 parts by mass of the oxetane compound. The content of curing agent A in the adhesive composition may be 11 parts by mass or more, 12 parts by mass or more, 13 parts by mass or more, or 14 parts by mass or more, and may be 18 parts by mass or less, 17 parts by mass or less, 16 parts by mass or less, or 15 parts by mass or less, based on 100 parts by mass of the oxetane compound.

[0051] [Conductive Particles] The adhesive composition may further contain conductive particles. The conductive particles are not particularly limited as long as they are conductive, and examples thereof include metal particles made of metals such as gold, silver, palladium, nickel, copper, and solder; conductive carbon particles made of conductive carbon; and coated conductive particles having a core containing non-conductive glass, ceramic, plastic (polystyrene, etc.), and a coating layer containing the above metal or conductive carbon that coats the core. The conductive particles may be coated conductive particles, which are easily deformed by heating and / or pressure and can increase the contact area between the electrodes and the conductive particles when electrically connecting electrodes, thereby further improving the conductivity between the electrodes. The conductive particles may be solder particles, which can strengthen the connection between the electrodes.

[0052] The solder particles may contain at least one selected from the group consisting of tin, a tin alloy, indium, and an indium alloy, from the viewpoint of achieving both connection strength and a low melting point. Furthermore, the solder particles may contain at least one selected from the group consisting of an In—Bi alloy, an In—Sn alloy, an In—Sn—Ag alloy, an Sn—Au alloy, an Sn—Bi alloy, an Sn—Bi—Ag alloy, an Sn—Ag—Cu alloy, and an Sn—Cu alloy, from the viewpoint of achieving higher reliability during a high-temperature, high-humidity test and a thermal shock test.

[0053] The average particle size of the conductive particles may be 1 μm or more, 2 μm or more, or 2.5 μm or more from the viewpoint of excellent dispersibility and conductivity. The average particle size of the conductive particles may be 20 μm or less, 15 μm or less, 10 μm or less, 8 μm or less, 6 μm or less, 5.5 μm or less, or 5 μm or less from the viewpoint of ensuring insulation between adjacent electrodes. From these viewpoints, the average particle size of the conductive particles may be 1 to 20 μm, 1 to 15 μm, 1 to 10 μm, 1 to 8 μm, or 1 to 6 μm.

[0054] The average particle diameter of the conductive particles is determined by observing 300 conductive particles contained in the adhesive composition using a scanning electron microscope (SEM), measuring the particle diameter of each conductive particle, and averaging the particle diameters of the 300 conductive particles. If the conductive particles are not spherical, the particle diameter of the conductive particles is determined as the diameter of a circle circumscribing the conductive particles in the image observed using the SEM.

[0055] The particle density of the conductive particles in the adhesive composition is set to 100 particles / mm from the viewpoint of obtaining a stable connection resistance. ２ More than 1000 pieces / mm ２ or more than 3000 pieces / mm ２ The particle density of the conductive particles in the adhesive composition may be 100,000 particles / mm or more from the viewpoint of ensuring insulation between adjacent electrodes. ２ Below, 50,000 pieces / mm ２ or less, or 30,000 pieces / mm ２ From these viewpoints, the particle density of the conductive particles in the adhesive composition may be 100 to 100,000 particles / mm ２ , 1000-50000 pieces / mm ２, or 3,000 to 30,000 pieces / mm ２ It may be.

[0056] The content of the conductive particles may be 10% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the adhesive composition, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the adhesive composition.

[0057] The content of the conductive particles may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 70 parts by mass or more, or 90 parts by mass or more, based on 100 parts by mass of the cationically polymerizable compound. The content of the conductive particles may be 200 parts by mass or less, 150 parts by mass or less, 120 parts by mass or less, or 100 parts by mass or less, based on 100 parts by mass of the cationically polymerizable compound.

[0058] When the adhesive composition contains conductive particles, the content of curing agent A in the adhesive composition may be 3 parts by mass or more, 5 parts by mass or more, 7 parts by mass or more, 10 parts by mass or more, 11 parts by mass or more, 12 parts by mass or more, 13 parts by mass or more, or 14 parts by mass or more, based on 100 parts by mass of the conductive particles. The content of curing agent A in the adhesive composition may be 40 parts by mass or less, 35 parts by mass or less, 30 parts by mass or less, 27 parts by mass or less, 25 parts by mass or less, 22 parts by mass or less, 20 parts by mass or less, 18 parts by mass or less, 17 parts by mass or less, 16 parts by mass or less, or 15 parts by mass or less, based on 100 parts by mass of the conductive particles. The content of curing agent A in the adhesive composition may be 3 to 40 parts by mass, 10 to 40 parts by mass, 3 to 30 parts by mass, or 5 to 30 parts by mass, based on 100 parts by mass of the conductive particles.

[0059] [Thermoplastic Resin] The adhesive composition may further contain a thermoplastic resin. By containing a thermoplastic resin, the adhesive composition can be easily formed into a film. Examples of the thermoplastic resin include phenoxy resin, polyester resin, polyamide resin, polyurethane resin, polyester urethane resin, acrylic rubber, etc. These may be used alone or in combination of two or more.

[0060] The weight average molecular weight (Mw) of the thermoplastic resin may be, for example, 5,000 or more, 10,000 or more, 20,000 or more, or 40,000 or more, and may be 200,000 or less, 100,000 or less, 80,000 or less, or 60,000 or less. The weight average molecular weight of the thermoplastic resin is a value measured by gel permeation chromatography (GPC) and converted using a calibration curve with standard polystyrene.

[0061] The content of the thermoplastic resin may be 5% by mass or more, 15% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the adhesive composition. The content of the thermoplastic resin may be 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less, based on the total mass of the adhesive composition.

[0062] The content of the thermoplastic resin may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more, based on 100 parts by mass of the cationically polymerizable compound. The content of the thermoplastic resin may be 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 40 parts by mass or less, or 20 parts by mass or less, based on 100 parts by mass of the cationically polymerizable compound.

[0063] When the adhesive composition contains a thermoplastic resin, the content of curing agent A in the adhesive composition may be 3 parts by mass or more, 5 parts by mass or more, 7 parts by mass or more, 10 parts by mass or more, 12 parts by mass or more, 14 parts by mass or more, 16 parts by mass or more, 18 parts by mass or more, or 20 parts by mass or more, based on 100 parts by mass of the thermoplastic resin. The content of curing agent A in the adhesive composition may be 150 parts by mass or less, 130 parts by mass or less, 100 parts by mass or less, 80 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of the thermoplastic resin.

[0064] [Coupling Agent] The adhesive composition may further contain a coupling agent. By containing a coupling agent, the adhesive composition can further improve adhesion. The coupling agent may be a silane coupling agent, and examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and condensates thereof. These may be used alone or in combination of two or more.

[0065] The content of the coupling agent may be 0.5% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total mass of the adhesive composition, and 15% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total mass of the adhesive composition.

[0066] The content of the coupling agent may be 1 part by mass or more, 4 parts by mass or more, or 6 parts by mass or more based on 100 parts by mass of the cationically polymerizable compound, and may be 30 parts by mass or less, 20 parts by mass or less, 10 parts by mass or less, or 6 parts by mass or less based on 100 parts by mass of the cationically polymerizable compound.

[0067] When the adhesive composition contains a coupling agent, the content of curing agent A in the adhesive composition may be 25 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 60 parts by mass or more, 80 parts by mass or more, 100 parts by mass or more, 120 parts by mass or more, 140 parts by mass or more, 160 parts by mass or more, 180 parts by mass or more, or 200 parts by mass or more, based on 100 parts by mass of the coupling agent. The content of curing agent A in the adhesive composition may be 300 parts by mass or less, 270 parts by mass or less, 250 parts by mass or less, or 200 parts by mass or less, based on 100 parts by mass of the coupling agent.

[0068] [Filler] The adhesive composition may further contain a filler. By containing a filler, the adhesive composition can further improve connection reliability. Examples of the filler include non-conductive fillers (e.g., non-conductive particles). The filler may be either an inorganic filler or an organic filler.

[0069] Examples of inorganic fillers include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; metal nitride particles, etc. These may be used alone or in combination of two or more.

[0070] Examples of organic fillers include silicone particles, methacrylate-butadiene-styrene particles, acrylic-silicone particles, polyamide particles, polyimide particles, etc. These may be used alone or in combination of two or more.

[0071] The filler may be an inorganic filler or silica particles from the viewpoint of improving film formability and reliability of the connection structure. The silica particles may be crystalline silica particles or amorphous silica particles, and these silica particles may be synthetic products. The silica may be synthesized by a dry method or a wet method. The silica particles may include at least one type selected from the group consisting of fumed silica particles and sol-gel silica particles.

[0072] The silica particles may be surface-treated silica particles from the viewpoint of excellent dispersibility in the adhesive component. The surface-treated silica particles are, for example, silica particles whose surface hydroxyl groups have been hydrophobized with a silane compound or a silane coupling agent. The surface-treated silica particles may be, for example, silica particles surface-treated with a silane compound such as an alkoxysilane compound, a disilazane compound, or a siloxane compound, or may be silica particles surface-treated with a silane coupling agent.

[0073] Examples of the alkoxysilane compound include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, dimethoxydiphenylsilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and 3,3,3-trifluoropropyltrimethoxysilane.

[0074] Examples of the disilazane compound include 1,1,1,3,3,3-hexamethyldisilazane, 1,3-diphenyltetramethyldisilazane, 1,3-bis(3,3,3-trifluoropropyl)-1,1,3,3-tetramethyldisilazane, and 1,3-divinyl-1,1,3,3-tetramethyldisilazane.

[0075] Examples of siloxane compounds include tetradecamethylcycloheptasiloxane, decamethylcyclopentasiloxane, hexaphenylcyclosiloxane, octadecamethylcyclononasiloxane, hexadecamethylcyclooctasiloxane, dodecamethylcyclohexasiloxane, octaphenylcyclotetrasiloxane, hexamethylcyclotrisiloxane, heptaphenyldisiloxane, tetradecamethylhexasiloxane, dodecamethylpentasiloxane, hexamethylcyclohex ... Methyldisiloxane, decamethyltetrasiloxane, hexamethoxydisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, 1,3-vinyltetramethyldisiloxane, 2,4,6-trimethyl-2,4,6-trivinylcyclotrisiloxane, 1,3-dimethoxy-1,1,3,3-tetraphenyldisiloxane, 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane, 1,3-dimethyl-1,3-diphenyl-1,3 -divinyldisiloxane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 1,1,1,3,5,5,5,-heptamethyl-3-(3-glycidroxypropyl)trisiloxane, 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane, 1,1,1,3,5,5,5,-heptamethyl-3-[(trimethylsilyl)oxy]trisiloxane, 1,3,-bis[2-( 7-oxabicyclo[4.1.0]heptan-3-yl)ethyl]-1,1,3,3-tetramethyldisiloxane, 1,1,1,5,5,5-hexamethyl-3-[(trimethylsilyl)oxy]-3-vinyltrisiloxane, 3-[[dimethyl(vinyl)silyl]oxy]-1,1,5,5-tetramethyl-3-phenyl-1,5-vinyltrisiloxane, octavinyloctasilsesquioxane, and octaphenyloctasilsesquioxane.

[0076] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(amino)-2-(methyl ... N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-trimethoxysilylpropylsuccinic anhydride.

[0077] The silica particles that have been surface-treated with a silane compound or a silane coupling agent may be further surface-treated with a silane compound such as 3-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, or trimethoxyphenylsilane to further hydrophobize the hydroxyl group residues on the surface of the silica particles.

[0078] The surface-treated silica particles may comprise at least one selected from the group consisting of a reaction product (hydrolysis product) of silica and trimethoxyoctylsilane, a reaction product of silica and dimethylsiloxane, a reaction product of silicon dioxide or silica and dichloro(dimethyl)silane, a reaction product (hydrolysis product) of silica and bis(trimethylsilyl)amine, and a reaction product of silica and hexamethyldisilazane, or may comprise at least one selected from the group consisting of a reaction product of silica and trimethoxyoctylsilane, and a reaction product of silica and bis(trimethylsilyl)amine, from the viewpoint of easily controlling fluidity when the adhesive film for circuit connection is pressed when the adhesive composition is used as an adhesive film for circuit connection, and from the viewpoint of improving the mechanical properties and water resistance of the connection structure after pressing.

[0079] The filler content may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the adhesive composition. The filler content may be 50% by mass or less, 30% by mass or less, or 20% by mass or less, based on the total mass of the adhesive composition.

[0080] The content of the filler may be 10 parts by mass or more, 25 parts by mass or more, or 40 parts by mass or more based on 100 parts by mass of the cationically polymerizable compound. The content of the filler may be 100 parts by mass or less, 60 parts by mass or less, or 40 parts by mass or less based on 100 parts by mass of the cationically polymerizable compound.

[0081] When the adhesive composition contains a filler, the content of curing agent A in the adhesive composition may be 5 parts by mass or more, 8 parts by mass or more, 10 parts by mass or more, 12 parts by mass or more, 14 parts by mass or more, 16 parts by mass or more, 18 parts by mass or more, or 20 parts by mass or more, based on 100 parts by mass of the filler. The content of curing agent A in the adhesive composition may be 120 parts by mass or less, 100 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of the filler.

[0082] [Curing Inhibitor] The adhesive composition may further contain a curing inhibitor. Examples of curing inhibitors include amides having a lactam ring. When the adhesive composition contains an amide having a lactam ring, the adhesive composition can easily maintain excellent adhesiveness even when stored in a state exposed to air, and connection reliability can be easily ensured even when the connection structure is exposed to a high-temperature, high-humidity environment (e.g., 85°C, 85% RH) for a long period of time after connecting members with the adhesive composition.

[0083] The amide having a lactam ring may have 3 to 12 carbon atoms constituting the lactam ring. From the viewpoint of easily ensuring connection reliability even when the connection structure is exposed to a high-temperature, high-humidity environment (e.g., 85°C, 85% RH) for a long period of time, the number of carbon atoms constituting the lactam ring may be 3 to 10, 3 to 8, 3 to 7, or 3 to 6.

[0084] The amide having a lactam ring may have a functional group bonded to the lactam ring, such as a carboxy group, a carboxylate group, a hydroxy group, an alkoxy group, an alkyl group, an ester group, a sulfo group, a sulfonate group, a carbonyl group, an amino group, an amide group, a carboxamide group, a nitro group, a cyano group, or a halogen atom.

[0085] The amide having a lactam ring may comprise at least one member selected from the group consisting of 2-azetidinone, 2-pyrrolidinone (2-pyrrolidone), 2-piperidinone, ε-caprolactam, caprylolactam, and laurolactam (ω-laurinlactam), and may comprise ε-caprolactam, from the viewpoint that the adhesive composition will easily maintain excellent adhesive properties even when stored in a state in contact with air, and that the connection structure will easily ensure connection reliability even when exposed to a high-temperature, high-humidity environment (e.g., 85°C, 85% RH) for an extended period of time.

[0086] The content of the amide having a lactam ring may be 0.001% by mass or more, 0.003% by mass or more, or 0.005% by mass or more, or may be 2% by mass or less, 1% by mass or less, or 0.8% by mass or less, based on the total mass of the adhesive composition, from the viewpoint that the adhesive composition easily maintains excellent adhesive properties even when stored in contact with air, and from the viewpoint that the connection structure easily ensures connection reliability even when exposed to a high-temperature, high-humidity environment (e.g., 85°C, 85% RH) for an extended period of time. From these viewpoints, the content of the amide having a lactam ring may be 0.001 to 2% by mass, 0.003 to 1% by mass, or 0.005 to 0.8% by mass, based on the total mass of the adhesive composition.

[0087] The content of the amide having a lactam ring may be 0.001 parts by mass or more, 0.005 parts by mass or more, or 0.01 parts by mass or more, based on 100 parts by mass of the cationically polymerizable compound. The content of the amide having a lactam ring may be 1 part by mass or less, 0.5 parts by mass or less, or 0.1 parts by mass or less, based on 100 parts by mass of the cationically polymerizable compound.

[0088] When the adhesive composition contains an amide having a lactam ring, the content of curing agent A in the adhesive composition may be 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more, based on 0.01 parts by mass of the amide having a lactam ring. The content of curing agent A in the adhesive composition may be 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 4 parts by mass or less, based on 0.01 parts by mass of the amide having a lactam ring. The content of curing agent A in the adhesive composition may be 1 to 20 parts by mass, 2 to 10 parts by mass, or 3 to 5 parts by mass, based on 0.01 parts by mass of the amide having a lactam ring.

[0089] [Other Components] The adhesive composition may further contain other components in addition to the above components. The other components may include a stabilizer, a colorant, an antioxidant, a solvent, a curing agent other than curing agent A, etc. The adhesive composition may further contain a radical polymerizable compound and a radical polymerization initiator.

[0090] Examples of the radical polymerizable compound include acrylic compounds. Examples of the acrylic compounds include (meth)acrylic acid compounds, (meth)acrylate compounds, and imide compounds thereof. These may be used in the form of either a monomer or an oligomer, or a combination of a monomer and an oligomer. The radical polymerizable compound may be used alone or in combination of two or more.

[0091] Specific examples of the acrylic compound include alkyl(meth)acrylate compounds such as methyl acrylate, ethyl acrylate, isopropyl acrylate, and isobutyl acrylate; polyol poly(meth)acrylate compounds such as ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, and tetramethylolmethane tetraacrylate; aryloxy-hydroxyalkyl(meth)acrylate compounds such as 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, and 2,2-bis[4-(acryloxypolyethoxy)phenyl]propane; dicyclopentenyl acrylate, tricyclodecanyl acrylate, and tris(acryloyloxyethyl)isocyanurate.

[0092] The radical polymerization initiator may be one that generates free radicals by light or heat. Examples of the radical polymerization initiator include organic peroxides and azo compounds. Examples of the organic peroxide include peroxyesters, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyketals, hydroperoxides, and silyl peroxides. One type of radical polymerization initiator may be used alone, or two or more types may be used in combination.

[0093] Examples of peroxyesters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, L-hexylperoxy-2-ethylhexanoate, L t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, 1,1-bis(t-butylperoxy)cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(m-toluoylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, and t-butylperoxyacetate.

[0094] Examples of dialkyl peroxides include α,α'-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, etc. Examples of hydroperoxides include diisopropylbenzene hydroperoxide, cumene hydroperoxide, etc.

[0095] Examples of diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoylperoxytoluene, and benzoyl peroxide.

[0096] Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl)peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di(2-ethylhexylperoxy)dicarbonate, dimethoxybutyl peroxydicarbonate, and di(3-methyl-3-methoxybutylperoxy)dicarbonate.

[0097] Specific examples of peroxyketals include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-(t-butylperoxy)cyclododecane, and 2,2-bis(t-butylperoxy)decane.

[0098] Specific examples of silyl peroxides include t-butyltrimethylsilyl peroxide, bis(t-butyl)dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis(t-butyl)divinylsilyl peroxide, tris(t-butyl)vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis(t-butyl)diallylsilyl peroxide, and tris(t-butyl)allylsilyl peroxide.

[0099] When the adhesive composition is subjected to differential scanning calorimetry (DSC) under conditions of a nitrogen atmosphere, a temperature rise rate of 10°C / min, and a measurement temperature range of 40 to 300°C, multiple endothermic peaks may occur, or one endothermic peak may occur. When multiple endothermic peaks occur, the area ratio (first peak / second peak) of the endothermic peak that occurs first (first peak) to the endothermic peak that occurs second (second peak) may be 2 or more, 3 or more, or 5 or more, or may be 20 or less, 17 or less, or 15 or less.

[0100] When the adhesive composition is subjected to differential scanning calorimetry (DSC) under conditions of a nitrogen atmosphere, a heating rate of 10°C / min, and a measurement temperature range of 40 to 300°C, the heat generation amount calculated from the area of ​​the endothermic peak (first peak) that first occurs may be 50 J / g or more, 80 J / g or more, or 100 J / g or more, and may be 400 J / g or less, 350 J / g or less, or 300 J / g or less.

[0101] The reaction rate when the adhesive composition is heat-treated at 40°C for 15 hours may be 10% or less. The reaction rate was calculated using differential scanning calorimetry (DSC) from the first endothermic peak (first peak) according to the following formula: Reaction rate (%) = 100 × (1 - b / a) In the formula, a and b are as follows: a: total heat generation amount of unreacted materials (unit: J / g) b: total heat generation amount of reacted materials after heat treatment (unit: J / g)

[0102] The elastic modulus of the reaction product obtained by heating the adhesive composition at 180°C for 1 hour at a measurement temperature of 300°C may be 0.01 GPa or more, 0.05 GPa or more, or 0.1 GPa or more, or may be 5 GPa or less, 3 GPa or less, or 1 GPa or less. The elastic modulus at a measurement temperature of 300°C refers to the storage elastic modulus at 300°C when the adhesive composition is laminated to a thickness of 100 to 200 μm and heated in a thermostatic bath at 180°C for 1 hour to produce a cured film for evaluation, and the cured film is subjected to DMA measurement from 40 to 350°C using a dynamic viscoelasticity measuring device (for example, E4000 manufactured by UBM Corporation) at a heating rate of 10°C / min.

[0103] <Adhesive Film for Circuit Connection> The adhesive composition may be in the form of a film. That is, another embodiment of the present disclosure is an adhesive film for circuit connection that contains a cationically polymerizable compound and a curing agent A. The adhesive film for circuit connection may contain conductive particles.

[0104] The content of the cationically polymerizable compound in the adhesive film for circuit connection may be 10% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, based on the total mass of the adhesive film for circuit connection, from the viewpoint of ensuring the curability of the adhesive film for circuit connection. The content of the cationically polymerizable compound in the adhesive film for circuit connection may be 70% by mass or less, 50% by mass or less, 40% by mass or less, or 35% by mass or less, based on the total mass of the adhesive film for circuit connection, from the viewpoint of ensuring the formability of the adhesive film for circuit connection. From these viewpoints, the content of the cationically polymerizable compound in the adhesive film for circuit connection may be 10 to 70% by mass, based on the total mass of the adhesive film for circuit connection.

[0105] The content of curing agent A in the adhesive film for circuit connection may be 1% by mass or more, 2% by mass or more, or 3% by mass or more, based on the total mass of the adhesive film for circuit connection, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive film for circuit connection may be 20% by mass or less, 17% by mass or less, or 15% by mass or less, based on the total mass of the adhesive film for circuit connection, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive film for circuit connection may be 1 to 20% by mass, 2 to 17% by mass, or 3 to 15% by mass, based on the total mass of the adhesive film for circuit connection. The content of curing agent A in the adhesive film for circuit connection may be 4% by mass or more, 4.5% by mass or more, or 5% by mass or more, based on the total mass of the adhesive film for circuit connection, and may be 13% by mass or less, 11% by mass or less, 9% by mass or less, 7% by mass or less, or 5% by mass or less.

[0106] The content of curing agent A in the adhesive film for circuit connection may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive film for circuit connection excluding the conductive particles, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive film for circuit connection may be 20% by mass or less, 17% by mass or less, or 15% by mass or less, based on the total mass of the adhesive film for circuit connection excluding the conductive particles, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive film for circuit connection may be 1 to 20% by mass, 3 to 17% by mass, or 5 to 15% by mass, based on the total mass of the adhesive film for circuit connection excluding the conductive particles. The content of curing agent A in the adhesive film for circuit connection may be 4% by mass or more, 4.5% by mass or more, or 5% by mass or more, based on the total mass of the adhesive film for circuit connection excluding the conductive particles, and may be 13% by mass or less, 11% by mass or less, 9% by mass or less, 7% by mass or less, or 5% by mass or less.

[0107] The content of curing agent A in the adhesive film for circuit connection may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive film for circuit connection excluding the conductive particles and filler, from the viewpoint of sufficiently promoting the curing reaction. The content of curing agent A in the adhesive film for circuit connection may be 30% by mass or less, 27% by mass or less, 25% by mass or less, 22% by mass or less, or 20% by mass or less, based on the total mass of the adhesive film for circuit connection excluding the conductive particles and filler, from the viewpoint of improving the physical properties of the cured product. From these viewpoints, the content of curing agent A in the adhesive film for circuit connection may be 1 to 30% by mass, 3 to 27% by mass, or 5 to 20% by mass, based on the total mass of the adhesive film for circuit connection excluding the conductive particles and filler. The content of curing agent A in the adhesive film for circuit connection may be 6% by mass or more, 7% by mass or more, or 7.5% by mass or more, based on the total mass of the adhesive film for circuit connection excluding the conductive particles and filler, and may be 18% by mass or less, 16% by mass or less, 14% by mass or less, 12% by mass or less, 10% by mass or less, or 8% by mass or less.

[0108] The conductive particles may be arranged in a predetermined pattern in a planar view of the adhesive film for circuit connection. For example, the conductive particles may be arranged regularly in a planar view of the adhesive film for circuit connection, or may be arranged regularly and at approximately equal intervals in a planar view of the adhesive film for circuit connection. The position and number of the conductive particles can be determined, for example, depending on the shape, size, and pattern of the electrodes to be connected. The fact that at least a portion of the conductive particles are arranged in a predetermined pattern can be confirmed, for example, by observing the main surface of the adhesive film for circuit connection from above using an electron microscope. One method for regularly arranging the conductive particles in a planar view of the adhesive film for circuit connection includes, for example, preparing a substrate having a plurality of recesses on its surface, the recesses being regularly arranged in a predetermined pattern (for example, a pattern corresponding to the electrode pattern of a circuit component), arranging the conductive particles in the recesses, and then transferring the conductive particles to the adhesive film.

[0109] The particle density of the conductive particles in the adhesive film for circuit connection is set to 100 particles / mm from the viewpoint of obtaining stable connection resistance. ２ More than 1000 pieces / mm ２ or more than 3000 pieces / mm ２ The particle density of the conductive particles in the adhesive film for circuit connection may be 100,000 particles / mm or more from the viewpoint of ensuring insulation between adjacent electrodes. ２ Below, 50,000 pieces / mm ２ or less, or 30,000 pieces / mm ２ From these viewpoints, the particle density of the conductive particles in the adhesive film for circuit connection may be 100 to 100,000 particles / mm ２ , 1000-50000 pieces / mm ２ , or 3,000 to 30,000 pieces / mm ２ It may be.

[0110] The content of the conductive particles may be 10% by mass or more, 20% by mass or more, or 25% by mass or more, based on the total mass of the adhesive film for circuit connection, and 50% by mass or less, 40% by mass or less, or 30% by mass or less, based on the total mass of the adhesive film for circuit connection.

[0111] The content of the thermoplastic resin in the adhesive film for circuit connection may be 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total mass of the adhesive film for circuit connection. The content of the thermoplastic resin in the adhesive film for circuit connection may be 40% by mass or less, 30% by mass or less, or 20% by mass or less, based on the total mass of the adhesive film for circuit connection.

[0112] The content of the coupling agent in the adhesive film for circuit connection may be 0.5% by mass or more, 1% by mass or more, or 1.5% by mass or more, based on the total mass of the adhesive film for circuit connection, and 10% by mass or less, 5% by mass or less, or 2% by mass or less, based on the total mass of the adhesive film for circuit connection.

[0113] The content of the filler in the adhesive film for circuit connection may be 5% by mass or more, 10% by mass or more, or 12% by mass or more, based on the total mass of the adhesive film for circuit connection. The content of the filler in the adhesive film for circuit connection may be 30% by mass or less, 20% by mass or less, or 15% by mass or less, based on the total mass of the adhesive film for circuit connection.

[0114] The content of each component of the adhesive film for circuit connection based on 100 parts by mass of the cationically polymerizable compound may be within the same range as the content of each component of the adhesive composition based on 100 parts by mass of the cationically polymerizable compound.

[0115] The adhesive film for circuit connection may be a single layer, or may have a multilayer structure in which multiple layers are laminated. When the adhesive film for circuit connection has a multilayer structure, it may have, for example, a first adhesive layer containing a cationically polymerizable compound and a curing agent A, and a second adhesive layer other than the first adhesive layer. That is, the adhesive film for circuit connection may have a first adhesive layer and a second adhesive layer laminated on the first adhesive layer. At least one of the first adhesive layer and the second adhesive layer may contain a cationically polymerizable compound, a curing agent A, and conductive particles. When the adhesive film for circuit connection has a multilayer structure, the content of each of the above components in each layer may be within the above content range based on the total mass of each layer, or may be within the above content range based on the total mass of each layer.

[0116] The adhesive film for circuit connection may have multiple regions with different types and contents of components. The adhesive film for circuit connection may, for example, have a first region and a second region disposed on the first region, where the first region may contain a cationically polymerizable compound and curing agent A. That is, the adhesive film for circuit connection may have a first region formed from a first adhesive composition containing a cationically polymerizable compound and curing agent A, and a second region formed from a second adhesive composition disposed on the first region. When the adhesive film for circuit connection has multiple regions, the content of each of the above-mentioned components in each region may be within the above-mentioned content ranges based on the total mass of each region, or may be within the above-mentioned content ranges based on the total mass of each region.

[0117] The adhesive film for circuit connection may be provided on a substrate (e.g., a PET film) etc. The adhesive film for circuit connection with a substrate can be produced, for example, by applying an adhesive composition containing conductive particles onto the substrate using a knife coater, roll coater, applicator, comma coater, die coater or the like.

[0118] Fig. 1 is a schematic cross-sectional view showing an adhesive film for circuit connection according to one embodiment. As shown in Fig. 1, in one embodiment, the adhesive film for circuit connection 1 is composed of a single layer made of an adhesive component 2 and conductive particles 3 dispersed in the adhesive component 2. In one embodiment, the adhesive component 2 contains at least a cationically polymerizable compound and a curing agent A. The adhesive film for circuit connection 1 may be in an uncured state or in a partially cured state.

[0119] The thickness of the adhesive film 1 for circuit connection may be, for example, 3 μm or more or 10 μm or more, and may be 30 μm or less or 20 μm or less.

[0120] In one embodiment, the adhesive film for circuit connection may have a multilayer structure having two or more layers. For example, as shown in FIG. 2 , the adhesive film for circuit connection 1 may have a two-layer structure including a layer 1A containing conductive particles 3A (a first adhesive layer consisting of adhesive component 2A and conductive particles 3A dispersed in adhesive component 2A) and a layer 1B not containing conductive particles (a second adhesive layer consisting of adhesive component 2B). In this case, the first adhesive layer 1A may be a layer consisting of an adhesive composition (first adhesive composition) containing a cationically polymerizable compound, a curing agent A, and conductive particles. The second adhesive layer 1B may be a layer consisting of an adhesive composition (second adhesive composition) containing a cationically polymerizable compound and a curing agent A. The types, contents, etc. of the components contained in the second adhesive layer 1B may be the same as or different from those of the first adhesive layer 1A. The first adhesive layer 1A and the second adhesive layer 1B of the adhesive film for circuit connection 1 may each be in an uncured state or in a partially cured state.

[0121] The thickness of the first adhesive layer 1A may be, for example, 3 μm or more or 5 μm or more, and 15 μm or less or 10 μm or less. The thickness of the second adhesive layer 1B may be, for example, 3 μm or more or 10 μm or more, and 20 μm or less or 15 μm or less. The thickness of the first adhesive layer 1A may be the same as or different from the thickness of the second adhesive layer 1B. The ratio of the thickness of the first adhesive layer 1A to the thickness of the second adhesive layer 1B (thickness of the first adhesive layer 1A / thickness of the second adhesive layer 1B) may be 0.1 or more or 0.3 or more, and 1.5 or less or 0.5 or less.

[0122] The adhesive film for circuit connection may be an anisotropically conductive adhesive film (anisotropically conductive film), or may be a conductive adhesive film that does not have anisotropic conductivity.

[0123] <Connection Structure> Another embodiment of the present disclosure is a connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connection portion comprises a cured product of the above-described adhesive film for circuit connection.

[0124] 3 is a schematic cross-sectional view showing one embodiment of a connection structure 10. As shown in FIG. 3, the structure 10 includes a first circuit member 4 and a second circuit member 5 facing each other, and a connection portion 6 between the first circuit member 4 and the second circuit member 5, connecting the first circuit member 4 and the second circuit member 5.

[0125] The first circuit member 4 includes a first circuit board 41 and a first electrode 42 formed on a main surface 41 a of the first circuit board 41. The second circuit member 5 includes a second circuit board 51 and a second electrode 52 formed on a main surface 51 a of the second circuit board 51.

[0126] There are no particular limitations on the first circuit member 4 and the second circuit member 5 as long as they are members on which electrodes that require electrical connection are formed. Examples of members on which electrodes are formed (circuit members, etc.) include inorganic substrates such as semiconductors, glass, and ceramics; polyimide substrates such as TCP, FPC, and COF; substrates on which electrodes are formed on films such as polycarbonate, polyester, and polyethersulfone; and printed wiring boards, and a combination of these may also be used.

[0127] The connection portion 6 includes a cured product of the adhesive film for circuit connection 1, and contains an insulating material 7 that is a cured product of the adhesive component 2, and conductive particles 3. The conductive particles 3 may be disposed not only between the opposing first electrode 42 and second electrode 52, but also between the main surface 41 a of the first circuit board 41 and the main surface 51 a of the second circuit board 51. In the structure 10, the first electrode 42 and the second electrode 52 are electrically connected via the conductive particles 3. That is, the conductive particles 3 are in contact with both the first electrode 42 and the second electrode 52.

[0128] In the structure 10, as described above, the opposing first electrode 42 and second electrode 52 are electrically connected via the conductive particles 3. This sufficiently reduces the connection resistance between the first electrode 42 and the second electrode 52. This allows the current to flow smoothly between the first electrode 42 and the second electrode 52, allowing the first circuit member 4 and the second circuit member 5 to fully exhibit their functions.

[0129] <Method for manufacturing a connection structure> Another embodiment of the present disclosure is a method for manufacturing a connection structure, comprising the steps of interposing the above-mentioned adhesive film for circuit connection between a first circuit member having a first electrode and a second circuit member having a second electrode, and thermocompression bonding the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other.

[0130] 4 is a schematic cross-sectional view showing one embodiment of a method for producing a connection structure. As shown in FIG. 4( a), first, a first circuit member 4 and an adhesive film for circuit connection 1 are prepared. Next, the adhesive film for circuit connection 1 is placed on the main surface 41a of the first circuit member 4. When the adhesive film for circuit connection 1 is laminated on a substrate (not shown), the laminate is placed on the first circuit member 4 with the adhesive film for circuit connection 1 side of the substrate facing the first circuit member 4. When the adhesive film for circuit connection 1 has a first adhesive layer 1A and a second adhesive layer 1B as shown in FIG. 2, it is preferable to place the adhesive layer containing conductive particles (first adhesive layer 1A) in contact with the main surface 41a of the first circuit member 4, from the viewpoint of increasing the number of conductive particles captured between the opposing electrodes.

[0131] The adhesive film for circuit connection 1 is then pressed in the directions of arrows A and B in Figure 4(a) to temporarily connect the adhesive film for circuit connection 1 to the first circuit member 4 (see Figure 4(b)). At this time, heating may be performed together with the pressing.

[0132] 4(c), a second circuit member 5 is further placed on the adhesive film 1 for circuit connection placed on the first circuit member 4, with the second electrode 52 facing the first circuit member 4 (i.e., the first electrode 42 and the second electrode 52 are placed opposite each other, with the adhesive film 1 for circuit connection interposed between the first circuit member 4 and the second circuit member 5). If the adhesive film 1 for circuit connection is laminated on a substrate (not shown), the substrate is peeled off and then the second circuit member 5 is placed on the adhesive film 1 for circuit connection.

[0133] The adhesive film 1 for circuit connection is then thermocompressed in the directions of arrows A and B in Figure 4(c) , thereby hardening the adhesive film 1 for circuit connection and achieving a permanent connection that electrically connects the first electrode 42 and the second electrode 52 to each other, resulting in a structure 10 as shown in Figure 3 .

[0134] In the structure 10 obtained as described above, it is possible to bring the conductive particles 3 into contact with both the opposing first electrode 42 and second electrode 52, and the connection resistance between the first electrode 42 and the second electrode 52 can be sufficiently reduced.

[0135] By applying pressure to the adhesive film for circuit connection 1 while heating it, the adhesive component 2 hardens to form an insulating material 7 while the distance between the first electrode 42 and the second electrode 52 is kept sufficiently small, and the first circuit member 4 and the second circuit member 5 are firmly connected via the connecting portion 6. Furthermore, in the structure 10, a state in which the adhesive strength is sufficiently high is maintained for a long period of time. Therefore, in the structure 10, changes over time in the distance between the first electrode 42 and the second electrode 52 are sufficiently suppressed, and the long-term reliability of the electrical properties between the first electrode 42 and the second electrode 52 is excellent.

[0136] The present disclosure will be specifically described below with reference to examples, but the present disclosure is not limited to the following examples.

[0137] <Preparation of adhesive film for circuit connection> A first adhesive composition for forming a first adhesive layer and a second adhesive composition for forming a second adhesive layer were prepared by mixing the components in the amounts (unit: parts by mass) shown in Table 1. Details of each component in Table 1 are as follows, and the amount of each component in the table represents the amount of non-volatile content. Cationic polymerizable compound A1: alicyclic epoxy resin (trade name: CEL8010, manufactured by Daicel Corporation) A2: oxetane compound (trade name: OXBP, manufactured by Ube Industries, Ltd.) A3: epoxy resin (trade name: JER1007, manufactured by Mitsubishi Chemical Corporation) Curing agent B1: curing agent synthesized in Synthesis Example 1 described later B2: curing agent synthesized in Synthesis Example 2 described later Thermoplastic resin C: phenoxy resin a synthesized in Synthesis Example 3 described later Coupling agent D: silane coupling agent (3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-403) Filler E1: surface-treated silica particles (hydrolysis product of trimethoxyoctylsilane and silica, manufactured by Evonik Industries Aerosil R805 (manufactured by AG, product name, diluted with an organic solvent to a non-volatile content of 10% by mass) E2: surface-treated silica particles (hydrolysis product of silica and bis(trimethylsilyl)amine) Conductive particles F: conductive particles prepared as follows Hardening inhibitor G: ε-caprolactam

[0138] Synthesis Example 1 Synthesis of N,N-dimethyl,N-(4-methoxybenzyl)anilinium tetrakis(pentafluorophenyl)borate Step 1 A 200 mL Erlenmeyer flask with a magnetic stirrer equipped with a stirrer tip was prepared, and 100 mL of dehydrated acetone (FUJIFILM Wako Pure Chemical Industries, Ltd.), 3.11 g of 4-methoxybenzyl chloride (20 mmol, FUJIFILM Wako Pure Chemical Industries, Ltd.), and 6.00 g of sodium iodide (40 mmol, FUJIFILM Wako Pure Chemical Industries, Ltd.) were dissolved therein, followed by stirring at room temperature for 2 hours. After filtering the precipitate formed after stirring, the filtrate was washed three times with 100 mL of hexane (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 50 mL of water, respectively. 20 g of sodium sulfate (FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to the organic layer for dehydration. The organic solvent was distilled off to obtain 4.61 g (yield 99%) of 4-methoxybenzyl iodide as a pale yellow liquid.

[0139] [Step 2] A 200 mL Erlenmeyer flask with a magnetic stirrer and a stirrer tip was prepared, and 100 mL of hexane (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) and 4.61 g of 4-methoxybenzyl iodide (19 mmol, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) were mixed. 2.30 g of N,N-dimethylaniline (19 mmol, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) mixed with 5 mL of hexane was added dropwise to the Erlenmeyer flask and stirred at room temperature for 30 minutes. After stirring, 50 mL of methanol (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to the reaction mixture, and the methanol layer was washed three times with 100 mL of hexane. The methanol was then distilled off to obtain 6.00 g (yield 85%) of N,N-dimethyl,N-(4-methoxybenzyl)anilinium iodide.

[0140] [Step 3A] A 200 mL Erlenmeyer flask with a magnetic stirrer equipped with a stirrer tip was prepared, and 50 mL of ethyl acetate and 1.85 g (5.0 mmol) of N,N-dimethyl,N-(4-methoxybenzyl)anilinium iodide were mixed. 38.61 g of a 10% aqueous solution of sodium tetrakis(pentafluorophenyl)borate (5.0 mmol, manufactured by Nippon Shokubai Co., Ltd., TE-PB-NA-10-W) was added dropwise to the Erlenmeyer flask, followed by stirring at room temperature for 30 minutes. After stirring, the reaction mixture was washed once with 50 mL of saturated aqueous sodium bicarbonate, three times with 50 mL of water, and once with saturated saline, and the organic layer was dried over 20 g of sodium sulfate. The organic solvent was then distilled off, and the residue was dried under reduced pressure to obtain 2.16 g of N,N-dimethyl,N-(4-methoxybenzyl)anilinium tetrakis(pentafluorophenyl)borate (yield: 47%).

[0141] Synthesis Example 2 Synthesis of N,N-dimethyl,N-(4-methoxybenzyl)anilinium tetrakis(pentafluorophenyl)gallate N,N-dimethyl,N-(4-methoxybenzyl)anilinium tetrakis(pentafluorophenyl)gallate was synthesized in the same manner as in Synthesis Example 1, except that the 10% aqueous solution of sodium tetrakis(pentafluorophenyl)borate in Step 3A above was changed to an aqueous solution of sodium tetrakis(pentafluorophenyl)gallate.

[0142] Synthesis Example 3 Synthesis of Phenoxy Resin a In a 3000 mL three-neck flask equipped with a Dimroth condenser, a calcium chloride tube, and a Teflon (registered trademark) stirring rod connected to a stirring motor, 45 g of 4,4'-(9-fluorenylidene)-diphenol (Sigma-Aldrich Japan K.K.) and 50 g of 3,3',5,5'-tetramethylbiphenol diglycidyl ether (trade name: YX-4000H, Mitsubishi Chemical Corporation) were dissolved in 1000 mL of N-methylpyrrolidone to form a reaction solution. 21 g of potassium carbonate was added to this reaction solution, and the mixture was stirred for 3 hours while heating to 110°C using a mantle heater. The stirred reaction solution was added dropwise to a beaker containing 1000 mL of methanol, and the resulting precipitate was collected by suction filtration. The collected precipitate was further washed three times with 300 mL of methanol to obtain 75 g of phenoxy resin a. The molecular weight of the obtained phenoxy resin a was measured using a high performance liquid chromatograph (GP8020 manufactured by Tosoh Corporation, column: Gelpack GL-A150S and GLA160S manufactured by Showa Denko Materials K.K., eluent: tetrahydrofuran, flow rate: 1.0 mL / min), and the values ​​were Mn=15769, Mw=38045, and Mw / Mn=2.413, calculated in terms of polystyrene.

[0143] <Preparation of Conductive Particles> A layer made of nickel was formed on the surface of cross-linked polystyrene particles so as to have a thickness of 0.15 μm, thereby obtaining conductive particles having an average particle size of 3.0 μm.

[0144] The second adhesive composition was applied to a substrate (PET film) to form a second adhesive layer on the substrate. Furthermore, the first adhesive composition was applied to the second adhesive layer to form a first adhesive layer, thereby producing an adhesive film for circuit connection in which the first adhesive layer, the second adhesive layer, and the substrate were laminated in this order. The thickness of the first adhesive layer of each of the adhesive films for circuit connection in Example 1 and Comparative Example 1 was 7 μm, and the thickness of the second adhesive layer was 7 μm.

[0145] <Preparation of Connection Structure> As a first circuit member, an alkali-free glass substrate (OA-11, manufactured by Nippon Electric Glass Co., Ltd., outer dimensions: 38 mm × 28 mm, thickness: 0.3 mm) on the surface of which an AlNd (100 nm) / Mo (50 nm) / ITO (100 nm) wiring pattern (pattern width: 19 μm, space between electrodes: 5 μm) was formed was prepared. As a second circuit member, an IC chip (outer dimensions: 0.9 mm × 20.3 mm, thickness: 0.3 mm, bump electrode size: 70 μm × 12 μm, space between bump electrodes: 12 μm, bump electrode thickness: 8 μm) in which bump electrodes were arranged in two rows in a staggered pattern was prepared.

[0146] Connection structures were fabricated using the adhesive films for circuit connection obtained in the examples and comparative examples. First, a first adhesive layer of the adhesive film for circuit connection was placed on a first circuit member. Using a thermocompression bonding device (manufactured by Ohashi Manufacturing Co., Ltd.) consisting of a stage made of a ceramic heater and a tool (8 mm x 50 mm), the first adhesive layer was placed on a first circuit member at 60°C and 0.98 MPa (10 kgf / cm ２ ) for 1 second under the conditions of 0.15°C (145°C x 60 MPa), the adhesive film for circuit connection was attached to the first circuit member. The substrate on the side of the adhesive film for circuit connection opposite the first circuit member was then peeled off, and the bump electrodes of the first circuit member were aligned with the circuit electrodes of the second circuit member. Next, using a heat tool (8 mm x 45 mm), the second adhesive layer of the adhesive film for circuit connection was attached to the second circuit member via a 50 μm-thick PTFE sheet on a base heated to 60°C by heating and pressing at 145°C for 5 seconds at 60 MPa, thereby producing a connection structure. The temperature was the maximum temperature actually measured for the adhesive film for circuit connection, and the pressure was a value calculated relative to the total area of ​​the surface of the bump electrodes of the second circuit member facing the first circuit member.

[0147]

[0148] <DSC Measurement> Differential scanning calorimetry (DSC) was performed on the adhesive films for circuit connection obtained in each Example and Comparative Example using a differential scanning calorimeter (trade name: DSC2500, manufactured by TA Instruments Japan Co., Ltd.) under conditions of a nitrogen atmosphere, a heating rate of 10°C / min, and a measurement temperature range of 40 to 300°C. The endothermic peak that first appeared from the DSC measurement results was designated the first peak, and the endothermic peak that appeared after the first peak was designated the second peak. The presence or absence of a second peak and the area ratio of the first peak to the second peak (first peak / second peak) were calculated. The calorific value was also calculated from the area of ​​the first peak. The calculation results are shown in Table 2.

[0149] <Evaluation of Reaction Rate> The adhesive films for circuit connection obtained in each Example and Comparative Example were stored in a thermostatic chamber at 40°C for 15 hours, and then DSC measurement was carried out in the same manner as above. The measured calorific value was used to calculate the reaction rate according to the following formula. The reaction rate was evaluated as follows: A reaction rate of less than 10% was given an A rating, and a reaction rate of 10% or more was given an B rating. The evaluation results are shown in Table 2. Reaction rate (%) = 100 x (1 - b / a) In the formula, a and b are as follows: a: total calorific value of unreacted materials (unit: J / g) b: total calorific value of reacted materials after heat treatment (unit: J / g)

[0150] <Elastic Modulus Measurement> Using the adhesive compositions obtained in each Example and Comparative Example, a cured film for evaluation was produced by laminating a layer formed from the first adhesive composition and a layer formed from the second adhesive composition to a total thickness of 100 to 200 μm, with the layer being the same thickness, and heating the laminate in an oven at 180° C. for 1 hour. Thereafter, the cured film was subjected to DMA measurement using a dynamic viscoelasticity apparatus (product name: E-4000) manufactured by UBM Corporation, at a heating rate of 10° C. / min from 40 to 350° C., and the storage modulus at 300° C. was calculated.

[0151] <Evaluation of Connection Resistance> Using the connection structure, the connection resistance was measured at 14 locations using a four-terminal measurement method, and the maximum connection resistance value (maximum resistance value) after a high-temperature, high-humidity test was evaluated. The high-temperature, high-humidity test was performed by storing the connection structure for 250 hours in a constant temperature and humidity chamber set to a temperature of 110°C and a humidity of 85% RH, a temperature of 85°C and a humidity of 85% RH, and a temperature of 65°C and a humidity of 95% RH. A multimeter (MLR21, manufactured by ETAC) was used to measure the connection resistance. The connection resistance was evaluated as follows: a connection resistance of less than 1 Ω was rated A, a connection resistance of 1 Ω or more but less than 2 Ω was rated B, and a connection resistance of 2 Ω or more was rated C. The evaluation results are shown in Table 2.

[0152] <Evaluation of Corrosion Resistance by Artificial Sweat> After storing the connection structures soaked in artificial sweat in a constant temperature and humidity chamber at a temperature of 55°C and a humidity of 93% RH for 72 hours, the wiring portion of the connection structure was observed under a microscope to check for the presence or absence of corrosion. If corrosion was confirmed to be 5% or more of the entire area of ​​the wiring portion, it was determined that corrosion had occurred. To evaluate corrosion resistance, seven wiring portions of each of five connection structures were observed under a microscope, and the corrosion occurrence rate was calculated for a total of 35 locations. The calculation results are shown in Table 2.

[0153]

[0154] 1...adhesive film for circuit connection, 1A...first adhesive layer, 1B...second adhesive layer, 2, 2A, 2B...adhesive component, 3, 3A...conductive particles, 4...first circuit member, 5...second circuit member, 6...connection portion, 7...insulating material, 10...structure, 41...first circuit board, 42...first electrode, 51...second circuit board, 52...second electrode.

Claims

1. An adhesive composition comprising a cationically polymerizable compound and a curing agent, wherein the curing agent is a salt of a nitrogen-containing cation and an anion represented by the following general formula (1): [In formula (1), R １ represents a fluoroalkyl group, a fluoroaryl group, or a fluoroalkyl-substituted aryl group, m represents 0 or 1, and n represents an integer of 1 to 4.

2. The adhesive composition of claim 1, wherein the nitrogen-containing cation is an ammonium cation, an anilinium cation, or a pyridinium cation.

3. The adhesive composition according to claim 1, wherein the content of the curing agent is more than 5 parts by mass and not more than 40 parts by mass based on 100 parts by mass of the cationically polymerizable compound.

4. The adhesive composition according to claim 1, further comprising conductive particles.

5. The adhesive composition according to claim 4, wherein the content of the curing agent is 5 to 30 parts by mass based on 100 parts by mass of the conductive particles.

6. The adhesive composition according to claim 1, further comprising an amide having a lactam ring.

7. The adhesive composition according to claim 6, wherein the content of the curing agent is 1 to 20 parts by mass based on 0.01 part by mass of the amide having a lactam ring.

8. The adhesive composition according to claim 1, wherein the cationically polymerizable compound comprises an epoxy compound.

9. The adhesive composition according to claim 1, in which, when differential scanning calorimetry (DSC) is performed under conditions of a nitrogen atmosphere, a heating rate of 10°C / min, and a measurement temperature range of 40 to 300°C, a plurality of endothermic peaks are generated, and the ratio (first peak / second peak) of the first endothermic peak to the second endothermic peak (second peak) is 3 or more, or one endothermic peak is generated.

10. The adhesive composition according to claim 1, which has a reaction rate of 10% or less when heat-treated at 40°C for 15 hours.

11. The adhesive composition according to claim 1, in which the reaction product obtained by heating at 180°C for 1 hour has an elastic modulus at 300°C of 0.1 GPa or more.

12. An adhesive film for circuit connection, comprising an adhesive layer formed from the adhesive composition according to any one of claims 1 to 11.

13. An adhesive film for circuit connection having an adhesive layer formed from the adhesive composition according to claim 4 or 5, wherein the conductive particles are arranged in a predetermined pattern when viewed in a plane of the adhesive film for circuit connection.

14. An adhesive film for circuit connection, comprising a first adhesive layer and a second adhesive layer laminated on the first adhesive layer, wherein at least one of the first adhesive layer and the second adhesive layer is a layer formed from the adhesive composition described in any one of claims 1 to 11.

15. A connection structure comprising: a first circuit member having a first electrode; a second circuit member having a second electrode; and a connection portion disposed between the first circuit member and the second circuit member and electrically connecting the first electrode and the second electrode to each other, wherein the connection portion comprises a cured product of the adhesive film for circuit connection according to claim 12.

16. A method for producing a connection structure, comprising the steps of: interposing an adhesive film for circuit connection according to claim 12 between a first circuit member having a first electrode and a second circuit member having a second electrode; and thermocompressing the first circuit member and the second circuit member to electrically connect the first electrode and the second electrode to each other.

Images