WO2022224934A1

WO2022224934A1 - Adhesive composition and method for producing connection structure

Info

Publication number: WO2022224934A1
Application number: PCT/JP2022/018049
Authority: WO
Inventors: 将司大越; 由佳伊藤; 俊輔高木; 真弓佐藤; 健太菊地; 弘行伊澤
Original assignee: 昭和電工マテリアルズ株式会社
Priority date: 2021-04-19
Filing date: 2022-04-18
Publication date: 2022-10-27
Also published as: JPWO2022224934A1; TW202309224A

Abstract

Provided is an adhesive composition containing a polymerizable compound, a thermal polymerization initiator, and a dicarboxylic acid diester compound.

Description

ADHESIVE COMPOSITION AND CONNECTED STRUCTURE MANUFACTURING METHOD

The present invention relates to a method for manufacturing an adhesive composition and a connection structure.

In recent years, in the fields of semiconductors, liquid crystal displays, etc., various adhesives have been used as connecting materials for connecting electronic members (for example, connecting semiconductor chips and substrates). For example, Patent Literature 1 discloses an anisotropically conductive adhesive containing conductive particles.

The connection of electronic members using an adhesive is performed by pressing (thermocompression bonding) the electronic members while heating them with the adhesive interposed between the electronic members. As a result, a connection structure is obtained in which the electronic members are joined to each other and the connection portions of the electronic members are electrically connected to each other.

JP-A-1-251787

A main object of one aspect of the present invention is to provide an adhesive composition capable of reducing connection resistance between opposing connection portions in a connection structure using an electronic member.

Some aspects of the present invention provide the following [1] to [7].

[1] An adhesive composition containing a polymerizable compound, a polymerization initiator, and a dicarboxylic acid diester compound.

[2] The adhesive composition according to [1], wherein the polymerization initiator is a thermal polymerization initiator.

[3] Contains at least one compound selected from the group consisting of succinic acid diester, glutaric acid diester, adipic acid diester, pimelic acid diester, suberic acid diester, malic acid diester and phthalic acid diester as the dicarboxylic acid diester compound The adhesive composition according to [1] or [2].

[4] The adhesive composition according to any one of [1] to [3], wherein the content of the diester dicarboxylic acid compound is 0.01 to 40 parts by mass with respect to 100 parts by mass of the polymerizable compound. .

[5] The adhesive composition according to any one of [1] to [4], further containing conductive particles.

[6] The adhesive composition according to any one of [1] to [5], which is for circuit connection.

[7] Between the first electronic member having the first connection portion and the second electronic member having the second connection portion, the adhesive composition according to any one of [1] to [6] A connection structure comprising a step of electrically connecting the first connection portion and the second connection portion to each other by thermocompression bonding the first electronic member and the second electronic member with an object interposed therebetween. body manufacturing method.

According to the adhesive composition described in any one of [1] to [6] above, it is possible to reduce the connection resistance between opposing connection portions in a connection structure using an electronic member.

According to the manufacturing method described in [7] above, a connection structure having sufficiently low connection resistance between opposing connection portions can be obtained.

According to one aspect of the present invention, it is possible to provide an adhesive composition that reduces connection resistance between opposing connection portions in a connection structure using electronic members.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the connection structure. 2A to 2D are schematic cross-sectional views showing a method of manufacturing the connection structure of FIG. FIG. 3 is a schematic cross-sectional view showing another embodiment of the connection structure.

As used herein, "(meth)acrylate" means at least one of acrylate and its corresponding methacrylate. The same applies to other similar expressions such as "(meth)acryl" and "(meth)acryloyl". Moreover, "A or B" may include either one of A and B, or may include both. Also, "room temperature" means 25°C.

Unless otherwise specified, the materials exemplified below may be used singly or in combination of two or more. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. Further, a numerical range indicated using "-" indicates a range including the numerical values described before and after "-" as the minimum and maximum values, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or lower limit value of the numerical range at one step may be replaced with the upper limit value or lower limit value of the numerical range at another step. Moreover, in the numerical ranges described in this specification, the upper and lower limits of the numerical ranges may be replaced with the values shown in the examples. Moreover, the upper limit value and the lower limit value described individually can be combined arbitrarily.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

<Adhesive composition>
The adhesive composition of one embodiment comprises a polymerizable compound (hereinafter also referred to as "(A) component"), a polymerization initiator (hereinafter also referred to as "(B) component"), and a dicarboxylic acid diester compound (hereinafter referred to as "(B) component"). , Also referred to as "(C) component"). The polymerization initiator can also be called a curing agent in one aspect.

The adhesive composition of the present embodiment may be used for connecting electronic members. For example, the adhesive composition of the present embodiment is interposed between a first electronic member having a first connection portion and a second electronic member having a second connection portion, and the first electronic member and the second electronic member are crimped (for example, thermocompression) to electrically connect the first connecting portion and the second connecting portion to each other. The electronic member is, for example, a circuit member. That is, the adhesive composition of the present embodiment may be a circuit-connecting adhesive composition used for connecting circuit members.

According to the adhesive composition of the present embodiment, it is possible to reduce the connection resistance between the opposing connection portions in the connection structure using the electronic member. Moreover, according to the adhesive composition of the present embodiment, there is a tendency to obtain a connected structure having excellent connection reliability. That is, the bonded structure obtained using the adhesive composition of the present embodiment does not cause problems such as peeling even when exposed to a high-temperature and high-humidity atmosphere (for example, 85° C., 85% RH) for a long period of time. Therefore, it tends to be able to maintain a sufficiently low connection resistance even in a temperature cycle test.

The adhesive composition of the present embodiment may further contain conductive particles (hereinafter also referred to as "(D) component").

Each component contained in the adhesive composition of the present embodiment will be described below. Hereinafter, components other than the conductive particles in the adhesive composition are referred to as adhesive components.

[(A) polymerizable compound]
The component (A) is a polymerizable compound, for example, a compound polymerized by active species (radicals, cations, anions, etc.) generated by the polymerization initiator (component (B)). The component (A) may be a radically polymerizable compound, a cationically polymerizable compound, or an anionically polymerizable compound. The component (A) may be a cationically polymerizable compound from the viewpoint of improving the heat resistance after curing and making it easier to obtain a connected structure with excellent connection reliability. In this case, a cationic polymerization initiator is used as the component (B). Component (A) may be a monomer, oligomer or polymer. As the component (A), one type of compound may be used alone, or multiple types of compounds may be used in combination.

Examples of radically polymerizable compounds include (meth)acrylate compounds, maleimide compounds, citraconimide compounds, and nadimide compounds.

Specific examples of (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, 2-hydroxy-1,3-di(meth)acryloxypropane, 2,2-bis[4-((meth)acryloxymethoxy) Phenyl]propane, 2,2-bis[4-((meth)acryloxypolyethoxy)phenyl]propane, dicyclopentenyl (meth)acrylate, tricyclodecanyl (meth)acrylate, tris((meth)acryloyloxyethyl ) isocyanurate, isocyanuric acid EO-modified di(meth)acrylate, isocyanuric acid EO-modified tri(meth)acrylate, urethane (meth)acrylate and the like.

The radically polymerizable compound may have a crosslinked structure such as a tricyclodecane structure or a norbornane structure from the viewpoint of facilitating good fluidity and further reducing connection resistance. Among them, when a (meth)acrylate compound having a tricyclodecane structure is used, there is a tendency for the above effects to be remarkably obtained.

Examples of cationic polymerizable compounds include compounds having a cyclic ether group such as epoxy compounds and oxetane compounds. Examples of epoxy compounds include glycidyl ether type epoxy compounds and alicyclic epoxy compounds. As the cationic polymerizable compound, at least one compound selected from the group consisting of alicyclic epoxy compounds and oxetane compounds is used from the viewpoint of further improving the effect of reducing the connection resistance and from the viewpoint of further improving the connection reliability of the connection structure. good.

As the glycidyl ether-type epoxy compound, any compound having a glycidyl ether group in the molecule, which is cured by irradiation with actinic rays or by heating in the presence or absence of a curing agent, is known. can be used. Among them, a glycidyl ether type epoxy compound having two or more epoxy groups in one molecule is preferable because it has a high crosslink density when cured. Examples of glycidyl ether type epoxy compounds include bisphenol type epoxy resins derived from epichlorohydrin and bisphenol compounds (bisphenol A, bisphenol F, etc.); polyglycidyl ethers; novolacs such as cresol novolac type epoxy resins and phenol novolac type epoxy resins type epoxy compounds; biphenyl diglycidyl ether, glycidyl alkyl isocyanurate, polyglycidyl methacrylate, copolymers of glycidyl methacrylate and vinyl monomers copolymerizable therewith, and the like. Glycidyl ether type epoxy compounds may be used singly or in combination.

An alicyclic epoxy compound is a compound having an alicyclic epoxy group. The number of alicyclic epoxy groups in one molecule of the alicyclic epoxy compound may be one or two or more. When the number of alicyclic epoxy groups in one molecule of the alicyclic epoxy compound is two or more, the crosslink density after curing tends to be high. The number of alicyclic epoxy groups in one molecule of the alicyclic epoxy compound may be, for example, 6 or less.

Alicyclic epoxy compounds include compounds obtained by oxidizing compounds having an alicyclic structure such as cyclohexene and cyclopentene (for example, compounds having cyclohexene oxide, cyclopentene oxide, etc.).

Specific examples of alicyclic epoxy compounds include 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-methodioxane, 3,4-epoxy-1-methylcyclohexyl-3 ,4-epoxy-1-methylhexanecarboxylate, 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexanecarboxylate, 3,4-epoxy-5-methylcyclohexylmethyl-3 ,4-epoxy-5-methylcyclohexanecarboxylate, 3,4-epoxy-6-methylcycloexylcarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 6-methyl-3, 4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate, ethylenebis(3,4-epoxycyclohexanecarboxylate), dicyclopentadiene diepoxide, bis(3,4-epoxycyclohexylmethyl)adipate, Methylenebis(3,4-epoxycyclohexane), 3,4-epoxycyclohexylmethyl (meth)acrylate, (3,3',4,4'-diepoxy)bicyclohexyl, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl) which may be modified with ε-caprolactone, and the like. One of these alicyclic epoxy compounds may be used alone, or two or more of them may be used in combination.

Examples of commercially available alicyclic epoxy compounds include EHPE3150, EHPE3150CE, CEL (Celoxide) 8010, CEL (Celoxide) 2021P, CEL (Celoxide) 2081, and GT401 manufactured by Daicel Corporation.

The epoxy equivalent of the alicyclic epoxy compound may be, for example, 100-300 g/eq from the viewpoint of adhesive strength. Epoxy equivalent is determined according to JIS K 7236.

The content of the alicyclic epoxy compound is 5% by mass or more, 10% by mass or more, or 15% by mass, based on the total amount of the adhesive components, from the viewpoint of improving the curability of the adhesive composition. or more. The content of the alicyclic epoxy compound is 50% by mass or less, 40% by mass or less, or 30% by mass, based on the total amount of the adhesive components, from the viewpoint that the film-forming property of the adhesive composition is more excellent. % or less. From these viewpoints, the content of the alicyclic epoxy compound may be 5 to 50% by mass, 10 to 40% by mass, or 15 to 30% by mass based on the total amount of the adhesive components.

An oxetane compound is a compound having an oxetanyl group. The number of oxetanyl groups in one molecule of the oxetane compound may be one or two or more. When the number of oxetanyl groups in one molecule of the oxetane compound is two or more, the crosslink density after curing tends to be even higher, and a synergistic effect is likely to be obtained in combination with the alicyclic epoxy compound. The number of oxetanyl groups in one molecule of the oxetane compound may be, for example, 6 or less.

Examples of oxetane compounds include xylylenebisoxetane, 2-ethylhexyloxetane, 3-hydroxymethyl-3-methyloxetane, 3-hydroxymethyl-3-ethyloxetane, 3-hydroxymethyl-3-propyloxetane, 3-hydroxy methyl-3-n-butyloxetane, 3-hydroxymethyl-3-phenyloxetane, 3-hydroxymethyl-3-benzyloxetane, 3-hydroxyethyl-3-methyloxetane, 3-hydroxyethyl-3-ethyloxetane, 3- Hydroxyethyl-3-propyloxetane, 3-hydroxyethyl-3-phenyloxetane, 3-hydroxypropyl-3-methyloxetane, 3-hydroxypropyl-3-ethyloxetane, 3-hydroxypropyl-3-propyloxetane, 3- Hydroxypropyl-3-phenyloxetane, 3-hydroxybutyl-3-methyloxetane, 4,4′-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl, 3-ethyl-3{[(3-ethyl oxetane-3-yl)methoxy]methyl}oxetane and the like. These oxetane compounds may be used individually by 1 type, and may be used in combination of multiple types.

Commercially available oxetane compounds include, for example, ETERNACOLL OXBP (4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]biphenyl) manufactured by Ube Industries, OXSQ and OXT manufactured by Toagosei Co., Ltd. -121, OXT-221, OXT-101 and OXT-212.

The content of the oxetane compound is 5% by mass or more, 10% by mass or more, or 15% by mass or more based on the total amount of the adhesive components, from the viewpoint that the curability of the adhesive composition is more excellent. you can The content of the oxetane compound is 50% by mass or less, 40% by mass or less, or 30% by mass or less based on the total amount of the adhesive components, from the viewpoint that the film-forming property of the adhesive composition is more excellent. It's okay. From these viewpoints, the content of the oxetane compound may be 5 to 50% by mass, 10 to 40% by mass, or 15 to 30% by mass based on the total amount of the adhesive components.

The mass ratio of the content of the oxetane compound to the content of the alicyclic epoxy compound (oxetane compound/alicyclic epoxy compound) improves the reactivity of the oxetane compound, and the synergistic effect of the combination with the alicyclic epoxy compound is obtained. From the viewpoint of being easily obtained, it may be 0.2 or more, 0.5 or more, or 0.8 or more, and may be 5.0 or less, 2.0 or less, or 1.2 or less, and 0.2 to 5 .0, 0.5-2.0 or 0.8-1.2.

As the anionically polymerizable compound, compounds having a cyclic ether group such as the epoxy compounds and oxetane compounds described above can be used.

The content of the component (A) is 10% by mass or more, 15% by mass or more, or 20% by mass or more, based on the total amount of the adhesive components, from the viewpoint of improving the curability of the adhesive composition. can be The content of component (A) is 60% by mass or less, 50% by mass or less, or 45% by mass, based on the total amount of the adhesive components, from the viewpoint that the film-forming property of the adhesive composition is more excellent. may be: From these viewpoints, the content of component (A) may be 10 to 60% by mass, 15 to 50% by mass, or 20 to 45% by mass based on the total amount of adhesive components.

[(B) polymerization initiator]
The component (B) may be a thermal polymerization initiator that generates active species upon heating, or a photopolymerization initiator that generates active species upon irradiation with light (active energy rays). When the component (B) is a thermal polymerization initiator, the adhesive composition has thermosetting properties. When the component (B) is a photopolymerization initiator, the adhesive composition has photocurability.

The component (B) may be a radical polymerization initiator, a cationic polymerization initiator, or an anionic polymerization initiator. Component (B) can be appropriately selected according to the type of component (A). (B) component may be used individually by 1 type, and may be used in combination of multiple types.

As the thermal radical polymerization initiator, known thermal radical polymerization initiators such as organic peroxides and azo compounds can be used.

Specific examples of thermal radical polymerization initiators include 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)per Oxydicarbonate, cumyl peroxyneodecanoate, dilauroyl peroxide, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecano ate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoyl peroxy ) Hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyneoheptanoate, t-amylperoxy-2-ethylhexanoate ate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy-3,5,5-trimethylhexanoate, 3-hydroxy-1,1-dimethylbutylperoxyneodecanoate, t-amyl peroxyneodecanoate, di(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, t-hexylperoxyisopropyl monocarbonate, t-butyl peroxymaleate, t -butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(3-methylbenzoylperoxy)hexane, t-butylperoxy -2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxybenzoate, dibutylperoxytrimethyladipate, t-amylperoxy Organic peroxides such as normal octoate, t-amyl peroxyisononanoate, t-amyl peroxybenzoate; 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis (1 acetoxy-1-phenylethane), 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 4,4′-azobis(4-cyanovaleric acid), 1, 1′-azobis(1-cyclohexanecarbo nitrile) and other azo compounds.

A thermal cationic polymerization initiator is, for example, a salt compound composed of a cation and an anion. Thermal cationic polymerization initiators include, for example, BF ₄ ⁻ , BR ₄ ⁻ (R represents a phenyl group substituted with two or more fluorine atoms or two or more trifluoromethyl groups), PF ₆ ⁻ , SbF. Onium salts such as sulfonium salts, phosphonium salts, ammonium salts, diazonium salts and iodonium salts having anions such as ₆ ⁻ , AsF ₆ ⁻ and the like can be mentioned. Among onium salts, onium salts having an anion containing boron as a constituent element (for example, BF ₄ ⁻ or BR ₄ ⁻ ) tend to improve rapid curability. A preferred specific example of an anion containing boron as a constituent element is tetrakis(pentafluorophenyl)borate.

The cation of the onium salt may be a sulfonium salt or an ammonium salt from the viewpoint of easily obtaining a lower connection resistance. This tendency is stronger when ammonium salts (especially anilinium salts) are used.

The ammonium salt cations are N-benzyl-N,N-dimethylanilinium ion, N-(4-nitrobenzyl)-N,N-dimethylanilinium ion, N- (4-methoxybenzyl)-N,N-dimethylanilinium ion, N-(α-phenylbenzyl)-N,N-dimethylanilinium ion, N-(α-methylbenzyl)-N,N-dimethylanilinium ions, N-(1-naphthylmethyl)-N,N-dimethylanilinium ions or N-cinnamyl-N,N-dimethylanilinium ions.

As the thermal anionic polymerization initiator, known thermal anionic polymerization initiators such as dicyandiamide, amine salts, and modified imidazole compounds can be used. From the viewpoint of extending the pot life, the thermal anionic polymerization initiator may be microencapsulated by being coated with a polyurethane-based or polyester-based polymer compound or the like.

Photoradical polymerization initiators include oxime ester structure, bisimidazole structure, acridine structure, α-aminoalkylphenone structure, aminobenzophenone structure, N-phenylglycine structure, acylphosphine oxide structure, benzyldimethylketal structure, α-hydroxy A known photopolymerization initiator having a structure such as an alkylphenone structure can be used.

Examples of photocationic polymerization initiators include onium salts that release Lewis acids when irradiated with light. Examples of such onium salts include aromatic sulfonium salts of Group VIIa elements, aromatic onium salts of Group VIa elements, and aromatic onium salts of Group Va elements. Specifically, for example, triarylsulfonium hexafluoroantimonate, triphenylphenacylphosphonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, bis-[4-(diphenylsulfonio)phenyl]sulfide bisdihexa Fluoroantimonate, bis-[4-(di4'-hydroxyethoxyphenylsulfonio)phenyl]sulfide bisdihexafluoroantimonate, bis-[4-(diphenylsulfonio)phenyl]sulfide bisdihexafluorophos phate, and diphenyliodonium tetrafluoroborate.

A known photoanionic polymerization initiator can be used as the photoanionic polymerization initiator.

The content of component (B) may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more with respect to 100 parts by mass of component (A) from the viewpoint of improving the effect of reducing the connection resistance. The content of component (B) may be 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less with respect to 100 parts by mass of component (A) from the viewpoint of improving the effect of reducing the connection resistance. From these viewpoints, the content of component (B) may be 1 to 20 parts by mass, 3 to 15 parts by mass, or 5 to 10 parts by mass per 100 parts by mass of component (A).

[(C) Dicarboxylic acid diester compound]
Component (C) is a compound having two carboxylic acid ester groups. A carboxylic acid ester group is represented, for example, by —COOR ¹ (R ¹ represents a monovalent hydrocarbon group). The two carboxylic acid ester groups may be the same or different from each other.

The hydrocarbon group represented by R ¹ is, for example, a monovalent hydrocarbon group having 1 to 6 carbon atoms. That is, the two carboxylic acid ester groups (-COOR ¹ ) of component (C) may have a monovalent hydrocarbon group having 1 to 6 carbon atoms as the hydrocarbon group R ¹ . The hydrocarbon group may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or cyclic, and saturated or unsaturated. The chain aliphatic hydrocarbon group may be linear or branched.

The hydrocarbon group represented by R ¹ may be an alkyl group having 1 to 6 carbon atoms from the viewpoint of further improving the connection resistance reducing effect. That is, the two carboxylic acid ester groups (--COOR ¹ ) of component (C) may have an alkyl group having 1 to 6 carbon atoms as the hydrocarbon group R ¹ . Examples of alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, pentyl group, cyclopentyl group, hexyl group and cyclohexyl group. etc. Among these, when the hydrocarbon group represented by R ¹ is a methyl group or an ethyl group, the effect of reducing the connection resistance tends to be remarkably obtained.

The molecular weight of the component (C) may be 500 or less, 400 or less, or 300 or less from the viewpoint of easily obtaining good compatibility with other components. The molecular weight of component (C) may be, for example, 100 or more from the viewpoint of handling and weighing.

The component (C) may be liquid from the viewpoint of facilitating the acquisition of good compatibility with other components. Here, the term “liquid” means having fluidity at normal temperature and normal pressure (1 atm, 25° C.).

Component (C) includes, for example, compounds represented by the following formula (I).

In formula (I), R ¹ represents a monovalent hydrocarbon group and R ² represents a single bond or a divalent hydrocarbon group. R ¹ has the same definition as R ¹ in the carboxylic acid ester group described above. Two R ^1s may be the same or different.

The hydrocarbon group represented by R ² is, for example, a divalent hydrocarbon group having 1 to 6 carbon atoms. The hydrocarbon group may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or cyclic, and saturated or unsaturated. The chain aliphatic hydrocarbon group may be linear or branched. The hydrocarbon group may have a substituent. For example, at least one hydrogen in the hydrocarbon group may be substituted with a hydroxyl group.

The hydrocarbon group represented by R ² is an optionally substituted alkylene group (alkanediyl group) having 1 to 6 carbon atoms or a phenylene group from the viewpoint of improving the effect of reducing the connection resistance. good. Examples of the alkylene group having 1 to 6 carbon atoms include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6 - diyl group and the like. The phenylene group may be o(ortho)-phenylene group, m(meth)-phenylene group or p(para)-phenylene group. Among these, the hydrocarbon group represented by R ² is an ethylene group, 1-hydroxy-1,2-ethanediyl group, propane-1,3-diyl group, butane-1,4-diyl group or o-phenylene group. , there is a tendency that the effect of reducing the connection resistance is remarkably obtained.

Specific examples of the compound represented by formula (I) include succinic acid diester, glutaric acid diester, adipic acid diester, pimelic acid diester, suberic acid diester, malic acid diester, phthalic acid diester, isophthalic acid diester, and terephthalic acid diester. , 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and the like. Among these, when at least one compound selected from the group consisting of succinic acid diester, glutaric acid diester, adipic acid diester, pimelic acid diester, suberic acid diester, malic acid diester and phthalic acid diester is used, the connection resistance is reduced. At least one compound selected from the group consisting of succinic acid diesters, glutaric acid diesters, adipic acid diesters, malic acid diesters and phthalic acid diesters tends to further improve the effect and the connection reliability of the connection structure. When a compound is used, the effect of reducing the connection resistance is particularly improved, and the connection reliability of the connection structure tends to be particularly improved.

The content of component (C) is 0.01 part by mass or more, 0.1 part by mass or more, relative to 100 parts by mass of component (A) (polymerizable compound), from the viewpoint of improving the effect of reducing the connection resistance. It may be 1 part by mass or more, 3 parts by mass or more, 6 parts by mass or more, or 10 parts by mass or more. The content of the component (C) is 40 parts by mass or less and 31 parts by mass or less with respect to 100 parts by mass of the component (A) (polymerizable compound) from the viewpoint of easily obtaining a connected structure having excellent connection reliability. , 22 parts by mass or less, 20 parts by mass or less, 16 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less. From these viewpoints, the content of component (C) is 0.01 to 40 parts by mass, 0.01 to 20 parts by mass, 0.1 to 40 parts by mass, relative to 100 parts by mass of component (A) (polymerizable compound). It may be 10 parts by mass, 1 to 5 parts by mass, 3 to 40 parts by mass, 3 to 31 parts by mass, 3 to 22 parts by mass, 3 to 16 parts by mass, or 3 to 10 parts by mass.

[(D) Conductive particles]
The component (D) is particles having electrical conductivity. As component (D), for example, metal particles composed of metals such as gold, silver, palladium, nickel, copper, solder, etc., and conductive carbon particles composed of conductive carbon can be used. Component (D) is a coated conductive particle comprising a core containing non-conductive glass, ceramic, plastic (such as polystyrene), etc., and a coating layer containing the above metal or conductive carbon and covering the core. good.

When solder particles are used as the (D) component, there is a tendency for the (C) component to significantly reduce the connection resistance. The solder particles contain, for example, at least one selected from the group consisting of tin, tin alloys, indium, and indium alloys.

As the tin alloy, for example, In—Sn alloy, In—Sn—Ag alloy, Sn—Au alloy, Sn—Bi alloy, Sn—Bi—Ag alloy, Sn—Ag—Cu alloy, Sn—Cu alloy, etc. are used. be able to. Specific examples of these tin alloys include the following examples.
・In-Sn (52% by mass of In, 48% by mass of Sn, melting point 118° C.)
・In-Sn-Ag (In20% by mass, Sn77.2% by mass, Ag2.8% by mass, melting point 175° C.)
・Sn-Bi (43% by mass of Sn, 57% by mass of Bi, melting point 138°C)
・Sn-Bi-Ag (Sn 42% by mass, Bi 57% by mass, Ag 1% by mass, melting point 139°C) ・Sn-Ag-Cu (Sn 96.5% by mass, Ag 3% by mass, Cu 0.5% by mass, melting point 217°C)
・Sn-Cu (Sn 99.3% by mass, Cu 0.7% by mass, melting point 227°C)
・Sn-Au (Sn21.0% by mass, Au79.0% by mass, melting point 278°C)

As the indium alloy, for example, an In--Bi alloy, an In--Ag alloy, or the like can be used. Specific examples of these indium alloys include the following examples.
・In-Bi (In66.3% by mass, Bi33.7% by mass, melting point 72° C.)
・ In-Bi (In 33.0% by mass, Bi 67.0% by mass, melting point 109 ° C.)
・In-Ag (97.0% by mass of In, 3.0% by mass of Ag, melting point 145°C)
Note that the indium alloy containing tin described above is classified as a tin alloy.

Solder particles, from the viewpoint of obtaining higher connection reliability, In-Bi alloy, In-Sn alloy, In-Sn-Ag alloy, Sn-Au alloy, Sn-Bi alloy, Sn-Bi-Ag alloy, Sn -At least one selected from the group consisting of Ag--Cu alloys and Sn--Cu alloys.

The melting point of the solder particles may be lower than the connection temperature. The melting point of the solder particles may be, for example, 280° C. or less, 220° C. or less, 180° C. or less, 160° C. or less, or 140° C. or less. The melting point of the solder particles may be, for example, 100° C. or higher.

The average particle size of component (D) may be 1.0 μm or more, 2.0 μm or more, 2.5 μm or more, or 5.0 μm or more from the viewpoint of excellent dispersibility and conductivity. From the viewpoint of ensuring insulation between adjacent electrodes, the average particle size of the component (D) is 30.0 μm or less, 25.0 μm or less, 20.0 μm or less, 15.0 μm or less, 10.0 μm or less. It may be 0 μm or less or 5.0 μm or less. From these viewpoints, the average particle size of component (D) may be 1.0 to 30.0 μm, 2.0 to 20.0 μm, 2.5 to 20.0 μm, or 5.0 to 20.0 μm. . The average particle size of component (D) is the particle size obtained by measuring the particle size of 300 conductive particles contained in the adhesive composition by observation using a scanning electron microscope (SEM). is the average value of When the conductive particles are not spherical, the particle diameter of the conductive particles is the diameter of a circle circumscribing the conductive particles in the SEM observation image.

The content of component (D) may be 3% by mass or more, 5% by mass or more, or 8% by mass or more based on the total mass of the adhesive composition, from the viewpoint of obtaining better connection resistance. From the viewpoint of ensuring insulation between adjacent electrodes, the content of component (D) is 30% by mass or less, 20% by mass or less, or 15% by mass or less based on the total mass of the adhesive composition. good. From these viewpoints, the content of component (D) may be 3 to 30% by mass, 5 to 20% by mass, or 8 to 15% by mass based on the total mass of the adhesive composition.

[Other ingredients]
The adhesive composition may further contain components (other components) other than the components described above. Other components include, for example, thermoplastic resins, coupling agents, fillers, and the like. These components are included in the adhesive component.

- Thermoplastic resin The thermoplastic resin contributes to the improvement of the film formability of the adhesive composition. Examples of thermoplastic resins include phenoxy resins, polyester resins, polyamide resins, polyurethane resins, polyester urethane resins, acrylic rubbers, and epoxy resins (solid at 25°C). These may be used individually by 1 type, and may be used in combination of 2 or more types.

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

The content of the thermoplastic resin may be 1% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more, based on the total amount of the adhesive components. It's okay. The content of the thermoplastic resin may be 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less based on the total amount of the adhesive components. It's okay. The content of the thermoplastic resin may be 1 to 50% by mass, may be 5 to 40% by mass, may be 10 to 30% by mass, and may be 15 to 50% by mass, based on the total amount of the adhesive component. It may be 20% by mass.

- Coupling agent A coupling agent contributes to the improvement of adhesion. The coupling agent may be, for example, a silane coupling agent. Examples of coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane. , 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, N-2-(aminoethyl)-3-amino propylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and condensates thereof. . These may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the coupling agent may be 0.1% by mass or more, 0.5% by mass or more, or 1.0% by mass or more based on the total amount of the adhesive components. , 1.5% by mass or more. The content of the coupling agent may be 10% by mass or less, 8.0% by mass or less, or 5.0% by mass or less, based on the total amount of the adhesive components. 0% by mass or less. The content of the coupling agent may be 0.1 to 10% by mass, 0.5 to 8.0% by mass, or 1.0 to 5.0% by mass, based on the total amount of the adhesive components. It may be 0% by mass, or 1.5 to 3.0% by mass.

-Filling material Filling material contributes to the improvement of connection reliability. Fillers include non-conductive fillers (eg, non-conductive particles). The filler may be either an inorganic filler or an organic filler.

Examples of inorganic fillers include metal oxide particles such as silica particles, alumina particles, silica-alumina particles, titania particles, and zirconia particles; and metal nitride particles. These may be used individually by 1 type, and may be used in combination of 2 or more types.

Examples of organic fillers include silicone particles, methacrylate/butadiene/styrene particles, acrylic/silicone particles, polyamide particles, and polyimide particles. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The filler may be an inorganic filler from the viewpoint of improving the film formability and the reliability of the connection structure. This effect tends to be significantly obtained when the filler contains silica particles. The silica particles may be crystalline silica particles or amorphous silica particles. These silica particles may be synthetic. A method for synthesizing silica particles may be a dry method or a wet method. Silica particles may contain at least one selected from the group consisting of fumed silica particles and sol-gel silica particles.

The silica particles may be surface-treated silica particles from the viewpoint of excellent dispersibility in the adhesive component. 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. . The surface-treated silica particles are obtained, for example, by hydrophobizing the hydroxyl groups on the surfaces of silica particles with a silane compound or a silane coupling agent.

The content of the filler may be 0.1% by mass or more, 1.0% by mass or more, or 5.0% by mass or more, based on the total amount of the adhesive components, It may be 10% by mass or more. The content of the filler may be 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less based on the total amount of the adhesive components. you can The content of the filler may be 0.1 to 50% by mass, 1.0 to 40% by mass, or 5.0 to 30% by mass, based on the total amount of the adhesive components. may be from 10 to 20% by mass.

According to the findings of the present inventors, when the adhesive composition contains a compound having a carboxyl group, curing inhibition of the adhesive composition tends to occur, and the connection reliability of the connection structure decreases. Tend. This tendency is remarkable when the adhesive composition has cationic curability (that is, when the polymerizable compound is a cationic polymerizable compound and the polymerization initiator is a cationic polymerization initiator). Therefore, the content of the compound having a carboxyl group in the adhesive composition may be 0 to 0.05 parts by mass, or may be 0 parts by mass, with respect to 100 parts by mass of the polymerizable compound.

The adhesive composition described above may be formed into a film. When the adhesive composition contains conductive particles, the film-like adhesive composition (adhesive film) may have anisotropic conductivity. Here, "anisotropic conductivity" means that it conducts in the pressurized direction and maintains insulation in the non-pressurized direction. The particle density of component (D) in the adhesive film may be, for example, 100-100000 particles/mm ² , 1000-50000 particles/mm ² or 3000-30000 particles/mm ² .

The adhesive film may be a single layer or may have a multi-layer structure in which multiple layers are laminated. When the adhesive film has a multilayer structure, the content of each of the above components in each layer may be within the above range of content based on the total mass of each layer.

The adhesive film can be prepared, for example, by the following method. First, the above components (A), (B), (C), and, if necessary, (D) and other components are stirred, mixed, and kneaded in an organic solvent. to prepare a varnish composition (varnish-like adhesive composition). Then, the obtained varnish composition is applied onto the release-treated substrate using a knife coater, roll coater, applicator, comma coater, die coater, or the like, and the organic solvent is volatilized by heating. Thereby, an adhesive film can be formed on the substrate. At this time, the thickness of the adhesive film can be adjusted by adjusting the coating amount of the varnish composition. The thickness of the adhesive film may be, for example, 5 μm or more, or 10 μm or more, and may be 40 μm or less, 30 μm or less, or 20 μm or less.

The organic solvent used in the preparation of the varnish composition is not particularly limited as long as it has the property of dissolving or dispersing each component substantially uniformly. Examples of such organic solvents include toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, butyl acetate and the like. These organic solvents can be used alone or in combination of two or more. Stirring and mixing or kneading during preparation of the varnish composition can be performed using, for example, a stirrer, a kneader, a three-roll mill, a ball mill, a bead mill, a homodisper, or the like.

The base material is not particularly limited as long as it has heat resistance that can withstand the heating conditions when volatilizing the organic solvent. Examples of such substrates include oriented polypropylene (OPP), polyethylene terephthalate (PET), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, polyimide, cellulose, Substrates (for example, films) made of ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, or the like can be used.

The heating conditions for volatilizing the organic solvent from the varnish composition applied to the substrate can be appropriately set according to the organic solvent used. The heating conditions may be, for example, 40-120° C. for 0.1-10 minutes.

A part of the solvent may remain in the adhesive film without being removed. The solvent content in the adhesive film may be, for example, 0 to 10% by weight based on the total weight of the adhesive film.

The adhesive film may be provided in a state in which the adhesive film is releasably attached to a substrate (for example, the substrate used in the above production), that is, as an adhesive film with a substrate.

<Method for manufacturing connection structure>
Next, a method for manufacturing a bonded structure using the adhesive composition of the above embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic cross-sectional view showing a bonded structure obtained using an adhesive composition containing conductive particles. A connection structure 10A shown in FIG. 1 includes a first electronic member 1 and a second electronic member 2 facing each other, and a first electronic member and a connection member 3A that connects the first electronic member 2 and the second electronic member 2 .

The first electronic member 1 and the second electronic member 2 are, for example, members formed with connecting portions (wiring, bumps, electrodes, etc.) that require electrical connection such as circuit members. The first electronic member 1 includes a first substrate 11 and a first connection portion 12 formed on the main surface 11 a of the first substrate 11 . The second electronic member 2 includes a second substrate 21 and a second connection portion 22 formed on the main surface 21 a of the second substrate 21 . The first electronic member 1 and the second electronic member 2 may be the same or different.

The first electronic member 1 and the second electronic member 2 may be, for example, a glass substrate or plastic substrate on which electrodes are formed, a printed wiring board, a ceramic wiring board, a flexible wiring board, an IC chip, or the like. The first substrate 11 and the second substrate 21 may be made of inorganic materials such as semiconductors, glass, and ceramics, organic materials such as polyimide and polycarbonate, composite materials such as glass/epoxy, and the like. The first connection portion 12 and the second connection portion 22 are gold, silver, tin, ruthenium, rhodium, palladium, osmium, iridium, platinum, copper, aluminum, molybdenum, titanium, indium tin oxide (ITO), indium It may be formed of zinc oxide (IZO), indium gallium zinc oxide (IGZO), or the like.

In the connection structure 10A, the connection member 3A is made of the cured adhesive composition of the above embodiment. The cured product contains the conductive particles P and the cured product 31 of the adhesive component. At least part of the conductive particles P is interposed between the first connection portion 12 and the second connection portion 22 (in contact with both the first connection portion 12 and the second connection portion 22). The one connection portion 12 and the second connection portion 22 are electrically connected to each other.

FIG. 2 is a schematic cross-sectional view showing a manufacturing method of the connection structure 10A. In the manufacturing method of the connection structure 10A, first, the adhesive composition 5 is placed on the main surface 11a of the first electronic member 1 (see FIG. 2(a)). When the adhesive composition 5 is in the form of a film and is laminated on the base material, the adhesive composition 5 side (adhesive film side) of the base material should face the first electronic member 1. Then, a laminate comprising the adhesive composition 5 and the substrate is placed on the first electronic member 1 . At this time, pressurization may be performed, or heating may be performed together with the pressurization.

Subsequently, on the adhesive composition 5 placed on the first electronic member 1, the second connection portion 22 side is directed toward the first electronic member 1 (that is, the first connection portion 12 and the second connection part 22 are arranged opposite to each other), and the adhesive composition 5 is placed between the first electronic member 1 and the second electronic member 2 intervene (see FIG. 2(b)). Thereby, the laminate 8 shown in FIG. 2(b) is obtained. At this time, when the adhesive composition 5 is laminated on a base material (not shown), the second electronic member 2 is placed on the adhesive composition 5 after the base material is peeled off.

Then, the laminate 8 as a whole is heated and pressed (thermocompression bonded) in the direction indicated by the arrow in FIG. 2(b). Thereby, the first connection portion 12 and the second connection portion 22 are electrically connected to each other. At this time, when the adhesive composition 5 is thermosetting, the adhesive composition 5 is cured by the above operation, and the first connection portion 12 and the second connection portion 22 are bonded by the connection member 3A. be done. When the adhesive composition 5 is photocurable, the adhesive composition 5 is cured by irradiating light (for example, ultraviolet rays) in parallel with the thermocompression bonding, or before or after the thermocompression bonding. The one connecting portion 12 and the second connecting portion 22 are bonded together by the connecting member 3A. As a result, a connection structure 10A as shown in FIG. 1 is obtained.

The temperature and thermocompression bonding time during thermocompression bonding can be adjusted as appropriate, and when the adhesive composition 5 is thermosetting, the adhesive composition 5 is sufficiently cured to bond the first electronic member 1 and The temperature and time for thermocompression bonding may be appropriately adjusted so that the second electronic member 2 can be adhered. The temperature during thermocompression bonding (maximum temperature reached by the adhesive composition) may be, for example, 80 to 300°C. The thermocompression bonding time may be, for example, 0.5 seconds to 3 hours.

Light irradiation when the adhesive composition 5 is thermosetting can be performed using, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an LED light source, or the like. can. The integrated amount of light irradiation can be appropriately set, and may be, for example, 500 to 3000 mJ/cm ² .

Although the method for manufacturing the connection structure according to one embodiment has been described above, the method for manufacturing the connection structure is not limited to the above embodiment. For example, in the above embodiment, a method using an adhesive composition containing conductive particles has been described, but an adhesive composition that does not contain conductive particles may be used. FIG. 3 is a schematic cross-sectional view showing a connected structure obtained using an adhesive composition containing no conductive particles. The connection structure 10B is electrically connected by the connection member 3B containing no conductive particles and the first connection portion 12 and the second connection portion 22 being in contact with each other. The connection structure 10B can be manufactured in the same manner as the connection structure 10A, except that an adhesive composition containing no conductive particles is used as the adhesive composition 5.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited only to the following examples.

<Preparation of materials>
Materials shown below were prepared as materials for producing an adhesive composition.

(A) Polymerizable compound and (B) polymerization initiator AB-1: HX-3941HP (epoxy resin containing anionic polymerization type latent curing agent, 65% by mass of polymerizable compound and 35% by mass of imidazole microcapsule type curing agent (Asahi Kasei Chemicals, trade name)
・ A-1: jER1032H60 (triphenolmethane skeleton-containing polyfunctional solid epoxy, manufactured by Mitsubishi Chemical Corporation, trade name (“jER” is a registered trademark))
・ A-2: YL980 (glycidyl ether type epoxy compound, Japan Epoxy Resin Co., Ltd., trade name)
・ A-3: OXT-121 (xylylene bisoxetane, manufactured by Toagosei Co., Ltd., trade name)
・ A-4: GT401 (tetra (3,4-epoxycyclohexylmethyl) butanetetracarboxylic acid modified ε-caprolactone manufactured by Daicel Co., Ltd., trade name)
· A-5: DCP-A (diacrylate having a tricyclodecane skeleton, manufactured by Toagosei Co., Ltd., trade name)
· A-6: Polyurethane acrylate (UA1) synthesized in Synthesis Example 1 shown below
・ A-7: Light ester P-2M (2-methacryloyloxyethyl acid phosphate, manufactured by Kyoeisha Chemical Co., Ltd., trade name)
B-1: CXC-1821 (N-(4-methoxybenzyl)-N,N-dimethylanilium tetrakis(pentafluorophenyl)borate, manufactured by King Industries, trade name)
・ B-2: Nyper BMT-K40 (benzoyl peroxide, manufactured by NOF Corporation, trade name)

(C) Dicarboxylic acid diester compound, dimethyl succinate (manufactured by Tokyo Chemical Industry Co., Ltd.)
・Dimethyl glutarate (manufactured by Tokyo Chemical Industry Co., Ltd.)
・Dimethyl adipate (manufactured by Tokyo Chemical Industry Co., Ltd.)
・Dimethyl phthalate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)
・Diethyl glutarate (manufactured by Tokyo Chemical Industry Co., Ltd.)
・ DL-dimethyl malate (manufactured by Tokyo Chemical Industry Co., Ltd.)

(D) Thermoplastic resin D-1: FX293 (biphenylfluorene type phenoxy resin, weight average molecular weight: 45000, glass transition temperature: 158 ° C., manufactured by Nippon Steel Chemical & Materials Co., Ltd., trade name (methyl ethyl ketone, non-volatile content 40 mass used diluted in %))
・ D-2: ZX1356-2 (bisphenol A type and bisphenol F type copolymerized phenoxy resin, weight average molecular weight: 70000, glass transition temperature: 71 ° C., manufactured by Nippon Steel Chemical & Materials Co., Ltd., trade name (methyl ethyl ketone Use the one diluted to 50% by mass of non-volatile content))
・ D-3: PKHC (phenoxy resin, manufactured by Union Carbide)

(E) Coupling agent E-1: SH-6040 (3-glycidoxypropyltrimethoxysilane, manufactured by Dow Corning Toray Co., Ltd., trade name)
・ E-2: KBM503 (3-methacryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd., trade name)

(F) Filler F-1: SE2050 (silica fine particles, manufactured by Admatechs Co., Ltd., trade name)
・ F-2: R104 (silica fine particles, manufactured by Nippon Aerosil Co., Ltd., average particle size (primary particle size): 12 nm)

(G) Conductive particles G-1: STC-7 (Sn-Ag-Cu solder fine particles, manufactured by Mitsui Mining & Smelting Co., Ltd., trade name, average particle size: 8 μm, melting point: 219 ° C.)
・G-2: Type 5 (Sn72Bi28 solder fine particles, manufactured by Mitsui Mining & Smelting Co., Ltd., average particle size: 20 μm, melting point: 139 ° C.)

(Synthesis Example 1: Synthesis of polyurethane acrylate (UA1))
Poly(1,6-hexanediol carbonate) (trade name: Duranol T5652, manufactured by Asahi Kasei Chemicals Co., Ltd.) was added to a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser with a calcium chloride drying tube, and a nitrogen gas introduction tube. , number average molecular weight 1000) 2500 parts by mass (2.50 mol) and isophorone diisocyanate (manufactured by Sigma-Aldrich) 666 parts by mass (3.00 mol) were added dropwise substantially uniformly over 3 hours. Then, after introducing a sufficient amount of nitrogen gas into the reaction vessel, the inside of the reaction vessel was heated to 70 to 75° C. for reaction. Next, 0.53 parts by mass (4.3 mmol) of hydroquinone monomethyl ether (manufactured by Sigma-Aldrich) and 5.53 parts by mass (8.8 mmol) of dibutyltin dilaurate (manufactured by Sigma-Aldrich) were added to the reaction vessel. After that, 238 parts by mass (2.05 mol) of 2-hydroxyethyl acrylate (manufactured by Sigma-Aldrich) was added and reacted at 70° C. for 6 hours in an air atmosphere. This gave a polyurethane acrylate (UA1). The weight average molecular weight of polyurethane acrylate (UA1) was 15,000. The weight average molecular weight was measured using a standard polystyrene calibration curve from gel permeation chromatography (GPC) under the following conditions.
(Measurement condition)
Device: GPC-8020 manufactured by Tosoh Corporation
Detector: RI-8020 manufactured by Tosoh Corporation
Column: Gelpack GLA160S + GLA150S manufactured by Hitachi Chemical Co., Ltd.
Sample concentration: 120mg/3mL
Solvent: Tetrahydrofuran Injection volume: 60 μL
Pressure: 2.94×10 ⁶ Pa (30 kgf/cm ² )
Flow rate: 1.00mL/min

<Examples 1 to 15 and Comparative Example 1>
[Preparation of adhesive film]
After mixing the materials shown in Tables 1 and 2 with an organic solvent, the resulting mixture (varnish-like adhesive composition) was applied onto a release-treated PET (polyethylene terephthalate) film. Methyl ethyl ketone was used as the organic solvent. The materials shown in Tables 1 and 2 were blended so as to have the composition ratios shown in Tables 1 and 2 (the numerical values in the tables mean the non-volatile content). The coating was carried out so that the film-like adhesive composition (adhesive film) obtained after drying had a thickness of 24 to 26 μm. Then, by removing the organic solvent by drying, adhesive films of Examples 1 to 15 and Comparative Example 1 containing each component shown in Tables 1 and 2 were obtained.

<Confirmation of Side Reaction by Addition of Dicarboxylic Acid Diester Compound>
For the adhesive films of Example 1 and Comparative Example 1, DSC (differential scanning calorimetry) was used to measure the amount of heat generated when thermally cured immediately after preparation and the amount of heat generated when thermally cured after the accelerated test. Then, the presence or absence of side reactions due to the addition of the dicarboxylic acid diester compound was confirmed. The measurement was performed at 40 to 250°C (heating rate: 10°C/min). The accelerated test was performed by leaving the adhesive film in a constant temperature bath set at 40° C. for 15 hours. Table 3 shows the results.

As shown in the above results, Example 1 in which a dicarboxylic acid diester compound was added showed a good calorific value reduction rate comparable to Comparative Example 1 in which no dicarboxylic acid diester compound was added. No side reaction (effect on curing reaction) due to the addition of the compound was confirmed.

<Connection resistance evaluation>
[Production of connection structure]
Using the adhesive films of Examples 1 to 15 and Comparative Example 1 obtained above, connection structures (circuit connection structures) were produced. Specifically, first, as the first electronic member (circuit member) and the second electronic member (circuit member) used in Examples 1 to 12, 14 and 15 and Comparative Example 1, the pitch is 200 μm (line: space = 1: 1) and a glass epoxy printed wiring board (first electronic member) having a copper pattern (gold/nickel plating) with a thickness of 35 µm and a pitch of 200 µm (line: space = 1: 1) and a thickness A polyimide flexible printed board (second electronic member) having a copper pattern (gold/nickel plating) with a thickness of 21 μm was prepared. As the first electronic member (circuit member) and the second electronic member (circuit member) used in Example 13, an IC chip with gold bumps having a pitch of 20 μm and a bump height of 1.5 μm (first electronic member) and a glass substrate with an ITO electrode (second electronic member) having an electrode made of amorphous indium tin oxide (ITO) with a pitch of 20 μm on the glass substrate. Next, a strip-shaped adhesive film slit to a width of 0.6 mm was arranged on the first electronic member. Next, after aligning the connection portion (copper pattern or gold bump) of the first electronic member and the connection portion (copper pattern or ITO electrode) of the second electronic member, a heating tool with a width of 0.8 mm is used. It was heated and pressurized through a cushioning material (silicone rubber with a thickness of 200 μm). The heating and pressing conditions were 180° C./2 MPa/10 seconds for Examples 1 to 14 and Comparative Example 1, and 160° C./2 MPa/10 seconds for Example 15. By the above operation, the first electronic member and the second electronic member are adhered via the adhesive film, and the connecting portion (circuit electrode which is the first connecting portion) of the first electronic member and the second were electrically connected to each other (circuit electrodes, which are second connection portions) of the electronic member in (1) to obtain a connection structure (circuit connection structure).

[Evaluation of connection resistance]
The connection resistance (conduction resistance) of the fabricated connection structure was measured by the four-probe method at the initial stage (immediately after fabrication), after the high-temperature and high-humidity test, and after the cycle test. For the measurement, a constant current power supply R-6145 manufactured by Advantest Co., Ltd. is used to apply a constant current (1 mA) to the first connection portion (circuit electrode) and the second connection portion (circuit electrode) of the connection structure. was applied between The potential difference between the connecting portions when the current was applied was measured using a digital multimeter (R-6557 manufactured by Advantest Co., Ltd.). The average value of the potential difference was converted into a connection resistance value, and the initial connection resistance value, the connection resistance value after the high temperature and high humidity test, and the connection resistance value after the cycle test were measured. The high-temperature and high-humidity test was performed by storing the connected structure for 500 hours in a constant temperature and humidity chamber at a temperature of 85° C. and a humidity of 85% RH. In the cycle test, the connection structure was placed in a cycle tester, and 100 cycles, 250 cycles, and 500 cycles were performed with the following (1) to (4) as one cycle. The rate of temperature rise and temperature drop during each cycle was about 15°C/min.
(1) -40°C/30 minutes → (2) 25°C/5 minutes → (3) 100°C/30 minutes → (4) 25°C 5 minutes The measured connection resistance value is evaluated based on the criteria shown below. did. The results are shown in Tables 4-5.
A: 0.25Ω or less B: More than 0.25Ω and less than 0.3Ω C: 0.3Ω or more

DESCRIPTION OF SYMBOLS 1... First electronic member, 2... Second electronic member, 3A, 3B... Connection member, 5... Adhesive composition, 8... Laminate, 11... First substrate, 12... First connection part, 21... Second substrate, 22... Second connection part, P... Conductive particles, 10A, 10B... Connection structure.

Claims

An adhesive composition containing a polymerizable compound, a polymerization initiator, and a dicarboxylic acid diester compound.
The adhesive composition according to claim 1, wherein the polymerization initiator is a thermal polymerization initiator.
The dicarboxylic acid diester compound contains at least one compound selected from the group consisting of succinic acid diester, glutaric acid diester, adipic acid diester, pimelic acid diester, suberic acid diester, malic acid diester and phthalic acid diester. Item 3. The adhesive composition according to Item 1 or 2.
The adhesive composition according to any one of claims 1 to 3, wherein the content of the dicarboxylic acid diester compound is 0.01 to 40 parts by mass with respect to 100 parts by mass of the polymerizable compound.
The adhesive composition according to any one of claims 1 to 4, further comprising conductive particles.
The adhesive composition according to any one of claims 1 to 5, which is for circuit connection.
The adhesive composition according to any one of claims 1 to 6 is interposed between a first electronic member having a first connection portion and a second electronic member having a second connection portion. and thermocompression bonding the first electronic member and the second electronic member to electrically connect the first connecting portion and the second connecting portion to each other. Method.