JP2003317545A - Surface coated conductive particle, connecting member for circuit using the same, connecting method, and connecting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide surface coated conductive particles, by which an electrical insulating property in the electrode interval direction does not deteriorate, the connection resistance in the connection direction of the electrodes is made lower, and a superior connection reliability is obtained, while the number of required conductive particles is secured even if an interval between electrodes and the electrode width become very small, and to provide a connecting member for circuit using the same, a connecting method, and a connecting structure. <P>SOLUTION: In the surface coated conductive particle, the surface of the conductive particle is coated with a composition including polyphthalide expressed by formula (I). The connecting member for circuit comprises an insulating adhesive having fluidity by heating and a coated particle where the surface of the conductive particle is coated with an insulating material, and the coated particle is the surface coated conductive particle. In formula (I), R is a bivalent aromatic hydrocarbon group or a bivalent heterocyclic ring aromatic group; R<SB>1</SB>, which may be plural (2-4), is hydrogen, an alkyl group, a fluorinated alkyl group, an alkoxy group or halogen; X represents O or N-R<SB>3</SB>(R<SB>3</SB>represents the following group); Y represents SO<SB>2</SB>or CO; n represents the number of repeating unit of a polymer. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surface-coated conductive particles whose surfaces are coated with a composition containing a pressure-sensitive conductive polymer (polyphthalide), and a circuit connecting member and a circuit connecting method using the same. The present invention relates to a circuit connection structure.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display and a TCP or F
An anisotropic conductive adhesive in which conductive particles are dispersed in an adhesive is used for the connection between the PC and the TCP and the connection between the FPC and the printed wiring board. In recent years, even when a semiconductor silicon chip is mounted on a substrate, so-called flip chip mounting, in which the semiconductor silicon chip is directly mounted on the substrate face down instead of conventional wire bonding, has been performed. Application of a water-soluble adhesive has been started (JP-A-59-120436 and JP-A-60-120436).
191228, JP-A-1-251787, JP-A-7
-90237).

[0003]

In recent years, as electronic devices have become smaller and thinner, the density of circuits has been increasing, and the distance between electrodes and the width of electrodes have become extremely narrow. Further, regarding the connection of the semiconductor chips, the bumps used for the connection are becoming smaller and the gap between the bumps is becoming very narrow. Generally, when connecting opposing circuits using an adhesive containing conductive particles, in order to reduce the connection resistance, there are three or more, preferably five or more, conductive particles on the circuit or bump. It is necessary. However, when the width between the circuits and the interval between the bumps are reduced, it is necessary to increase the number of the conductive particles contained in the adhesive in order to arrange the required number of the conductive particles on the circuit. However, since the number of conductive particles existing between the circuits also increases, there is a problem that the insulating property is reduced. In order to solve such a problem, a technique has been devised so that the conductive particles are covered with an insulating resin so that the insulating property is maintained even when the particles come into contact with each other between circuits (Japanese Patent Application Laid-Open No. No. 62-40183). However, it is difficult to completely cover these conductive particles with an insulating resin, and it is difficult to secure insulation when the space between circuit spaces becomes narrow because the conductive portions are exposed. ing. To overcome this, if the thickness of the insulating resin layer to be coated is increased, insulation between circuit spaces is ensured, but there is a problem that connection resistance increases. The present invention secures the necessary number of conductive particles even if the electrode spacing and electrode width become extremely narrow due to the high density of the circuit accompanying the miniaturization and thinning of electronic devices, and the insulating property in the electrode spacing direction. Without a drop in
An object of the present invention is to provide a surface-coated conductive particle having a low connection resistance in a connection direction of an electrode and having excellent connection reliability, a circuit connection member using the same, a connection method, and a connection structure.

[0004]

Means for Solving the Problems The inventors of the present invention have studied a method for efficiently coating the periphery of conductive particles in the above situation, and as a result, have found that a composition containing a polyphthalide represented by the formula (1) is obtained. It has been found that, by performing the treatment described above, the connection resistance of the connection portion and the insulation between the circuit spaces can be compatible, and the present invention has been achieved. The present invention is a surface-coated conductive particle in which the surface of a conductive particle is coated with a composition containing [1] a pressure-sensitive conductive polymer. Further, the present invention is the surface-coated conductive particles according to claim 1, wherein the pressure-sensitive conductive polymer [2] is a polyphthalide represented by the formula (1).

[0005]

Embedded image (In the formula (1), R represents a divalent aromatic hydrocarbon group or
A divalent heterocyclic-containing aromatic group;₁Is hydrogen, alk
Group, fluorinated alkyl group, alkoxy group or halogen
This may be a plurality (2-4), and X
Is O or NR ₃(However, R₃Indicates the next group
You. ) And Y is SO₂Or CO and n is
Indicates the number of repeating units in Lima. )

Embedded image The present invention also provides [3] a circuit connecting member comprising an insulating adhesive having fluidity upon heating and a coated particle in which the surface of a conductive particle is covered with an insulating substance. ] Or a circuit-connecting member which is the surface-coated conductive particles according to [2]. Also, the present invention
[4] A connection method in which a circuit connecting member is interposed between substrates having opposing circuit electrodes, and the substrate having opposing circuit electrodes is pressed to electrically connect the electrodes in the pressing direction. A circuit connection method in which the circuit connection member is the circuit connection member according to the above [3]. In addition, the present invention provides [5] a circuit connecting member interposed between substrates having opposing circuit electrodes, and pressurizing the substrate having opposing circuit electrodes to electrically connect the electrodes in the pressing direction. In this connection structure, the circuit connection member is the circuit connection member according to the above [3].

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The pressure-sensitive conductive polymer used in the present invention is specifically preferably a polyphthalide of the formula (I),
This will be described. The polyphthalide represented by the formula (I) (hereinafter collectively referred to as polyphthalide) has a thickness of 10 nm.
When a pressure is applied in the thickness direction when the thickness is about 50,000 nm, a characteristic (pressure-sensitive conductivity) in which the electrical resistance in the thickness direction changes greatly to exhibit conductivity has recently been found. Since the pressure at this time is affected by the shape of the electrodes and the like, it cannot be said unconditionally. However, the pressure is relatively low at 4.9 KPa (0.05 kg / cm ² ) or more, and the pressure is relatively low before and after the pressure. Is more than 6 orders of magnitude (usually shows insulation at atmospheric pressure,
Shows conductivity when pressurized. ) Can be expressed. Here, the change of the electric resistance by 6 digits or more means that the change of the electric resistance (or current) before and after the pressurization becomes 6 digits or more when measured under a predetermined voltage application condition. More specifically, it means that the current value at a predetermined voltage changes from an order of 10 ^-12 A (insulator) to a conductive material of the order of 10 ^-6 A or more.

[0007] Examples of R (a divalent aromatic hydrocarbon group or a divalent heterocyclic-containing aromatic group) in the formula (I) include the following groups.

Embedded image

Here, R ₂ is the same as R ₁ described above, _and hydrogen,
An alkyl group, a fluorinated alkyl group, an alkoxy group, or a halogen (such as fluorine or chlorine);
Number). Ar ₁ is the following groups.

Embedded image

Ar ₂ includes the following groups.

Embedded image

The polyphthalide, even if it is a homopolymer,
It may be a copolymer or a blend thereof. In order to improve various properties such as sensitivity and adhesiveness, a phenol resin having a phthalide ring or an epoxy resin having a phthalide ring can be added.
The phenolic resin having a phthalide ring is a resin obtained by reacting phenolphthalein, phenol red, o-cresolphthalein, thymolphthalein, cresol red, and the like with formaldehyde.
In the reaction, a phenol or cresol may be added to form a co-oligomer (product).

As the epoxy resin having a phthalide ring, a resin obtained by reacting a phenol compound having a phthalide ring (or a sulfophthalide ring) represented by the formula (I) with epichlorohydrin can be used.

The phenolic resin having a phthalide ring and the epoxy resin having a phthalide ring can be blended within a range not exceeding 50% by weight. If it is used in excess of 50% by weight, the film after molding tends to become brittle. Here, the weight% is a percentage when the amount of the non-volatile component excluding the solvent is 100. Thermoplastic resins such as styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers; and heat resins such as epoxy resins, (meth) acrylic resins, maleimide resins, citraconic imide resins, nadiimide resins, and phenol resins. A curable resin or the like can be used as long as the properties are not deteriorated. Further, additives such as an accelerator, an antioxidant, a coloring agent, a flame retardant, and a coupling agent may be added.

The conductive particles used in the present invention are not particularly limited as long as they have a conductive property capable of obtaining an electrical connection. However, metal particles such as gold, silver, nickel, copper, cobalt, and solder can be used. A material coated with a conductive material such as carbon, carbon, ceramics, or plastic can also be used. Further, particles obtained by coating the particles coated with the conductive substance with gold or silver can also be used. At this time, the thickness of the metal layer to be coated should be 100 ° to obtain sufficient conductivity.
The above is preferable. The method for coating the surface of the conductive particles used in the present invention with polyphthalide is not particularly limited as long as the surface can be coated in a substantially uniform state, but usually the conductive particles are dissolved in a solution in which polyphthalide is dissolved. Is preferred, after immersion and stirring, the conductive particles are separated by a method such as filtration.

The solvent is not particularly limited as long as the polyphthalide of the formula (I) can be dissolved, and examples thereof include cyclohexanone, nitrobenzene, benzonitrile,
Organic solvents such as -hydroxybenzotrifluoride, tetrachloroethane, cresol, chloroform, dimethylformamide, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, sulfolane, sym-tetrachloroethane, and methylene chloride can be used.
The concentration of the polyphthalide contained in the treatment solution is 0.1.
It is preferably from 05% to 20% by weight. If the content is 0.05% by weight or less, the surface treatment is not effectively performed. If the content is 20% by weight or more, the amount of polyphthalide coated on the surface of the conductive particles increases, and the connection resistance increases. The temperature time for the treatment is not particularly limited, but is generally in the range of 20 to 100 ° C. for a treatment time of 10 seconds to 1 hour. The treated conductive particles are dried after filtration. Drying conditions are appropriately selected depending on the organic solvent used, but the drying is performed at room temperature to 250 ° C. When using a conductive material coated with a plastic or the like as the conductive particles,
Considering the heat resistance of plastic, drying temperature is 200 ℃
It is preferable to perform the following.

The thickness of the film to be coated is 10 nm to 50,0.
00 nm (that is, 0.01 μm to 50 μm) is preferred. This is because, when pressing in the thickness direction, this thickness is preferable in order to change the electrical resistance in the thickness direction by six digits or more before and after pressing. In other words, if the coating thickness is 10
If the thickness is less than nm, the insulation before pressurization (normal pressure) is not sufficient, and if it exceeds 50,000 nm, the electrical resistance does not change significantly even when the pressure is increased. Further, in addition to the conductive particles whose surface is coated with the polyphthalide, uncoated conductive particles can be mixed and used. Uncoated conductive particles include gold, silver, nickel, copper,
Metal particles such as cobalt and solder, carbon, or
It is obtained by coating ceramics, plastics and the like with the above-mentioned conductive material.

As the insulating adhesive having fluidity by heating used in the present invention, a thermosetting adhesive, a radical curing adhesive, a photocuring adhesive, a thermoplastic adhesive (hot melt) may be used. Can be. Having fluidity by heating means exhibiting fluidity by heating. The thermosetting adhesive contains an epoxy resin and a latent curing agent, and when it is used as a film adhesive, it preferably contains a film forming material. Epoxy resins include epichlorohydrin and bisphenol A, bisphenol F, bisphenol A
D, bisphenol-type epoxy resin derived from bisphenol S, etc., epoxy novolak resin derived from epichlorohydrin and phenol novolak or cresol novolak, naphthalene-based epoxy resin having a skeleton containing a naphthalene ring, glycidylamine, glycidyl ether, biphenyl, Various epoxy compounds having two or more glycidyl groups in one molecule, such as alicyclic compounds, can be used alone or in combination of two or more. These epoxy resins have impurity ions (Na ⁺ ,
It is preferable to use a high-purity product in which the content of Cl ⁻ or the like is reduced to 300 ppm or less to prevent electron migration.

The latent curing agents include imidazole, hydrazide, amine imide and dicyandiamide. These may be used alone or as a mixture, and may be used as a mixture with a decomposition accelerator, an inhibitor and the like. A microcapsule obtained by coating these curing agents with a polyurethane-based or polyester-based polymer substance or the like is preferable because the pot life is extended. In order to obtain a sufficient reaction rate, the compounding amount of the latent curing agent is 0.1 to 100 parts by weight of the total of the film forming material and the epoxy resin.
The amount is preferably from 60 to 60 parts by weight, more preferably from 1 to 20 parts by weight. If the amount of the latent curing agent is less than 0.1 part by weight, a sufficient reaction rate cannot be obtained, and good adhesive strength and small connection resistance tend to be hardly obtained. If the amount of the latent curing agent exceeds 60 parts by weight, the fluidity of the adhesive tends to decrease, the connection resistance increases, and the pot life of the adhesive tends to decrease.

When the liquid material is solidified and the constituent composition is formed into a film, the film-forming material is easy to handle and has mechanical properties that do not easily tear, break, or stick. It is a material that can be handled as a film in a normal state.
The film-forming material can be blended in order to impart adhesiveness and stress relaxation during curing in addition to film-forming properties. Examples of the film forming material include a phenoxy resin, a polyvinyl formal resin, a polystyrene resin, a polyvinyl butyral resin, a polyester resin, a polyamide resin, a xylene resin, and a polyurethane resin. Phenoxy resins are preferred among the film-forming materials because of their excellent adhesiveness, compatibility, heat resistance, and mechanical strength. The phenoxy resin is a resin obtained by reacting a bifunctional phenol and epihalohydrin to a high molecular weight or by polyaddition of a bifunctional epoxy resin and a bifunctional phenol. Specifically, it is obtained by reacting 1 mol of bifunctional phenols with epihalohydrin 0.985 to 1.015 in a non-reactive solvent at a temperature of 40 to 120 ° C. in the presence of an alkali metal hydroxide. Can be. In addition, from the viewpoint of the mechanical and thermal properties of the resin, particularly, the blending equivalent ratio of the bifunctional epoxy resin and the bifunctional phenol is set so that epoxy group / phenol hydroxyl group = 1 / 0.9 to 1 / 1.1. In the presence of a catalyst such as an alkali metal compound, an organic phosphorus compound, a cyclic amine compound or the like, the reaction solid content in an organic solvent such as an amide, ether, ketone, lactone, or alcohol solvent having a boiling point of 120 ° C. or higher is used. Is less than 50 parts by weight
Those obtained by heating to ~ 200 ° C and performing a polyaddition reaction are preferred. Bifunctional epoxy resins include bisphenol A
Epoxy resin, bisphenol F epoxy resin, bisphenol AD epoxy resin, bisphenol S epoxy resin, and the like. Bifunctional phenols have two phenolic hydroxyl groups and include, for example, hydroquinones, bisphenol A, bisphenol F,
And bisphenols such as bisphenol AD and bisphenol S. The phenoxy resin may be modified with a radical polymerizable functional group, an epoxy group, a carboxyl group, or the like, and in this case, heat resistance is improved. The phenoxy resin may have a molecular structure derived from a polycyclic aromatic compound in the molecule. For example, dihydroxy compounds such as naphthalene, biphenyl, acenaphthene, fluorene, dibenzofuran, anthracene, and phenanthrene are preferable, and 9,9′-bis (4-hydroxyphenyl) fluorene is particularly preferable. The compounding amount of the film forming material is 2 to 80% by weight,
% By weight, particularly preferably 10 to 60% by weight.
If it is less than 2% by weight, stress relaxation and adhesive strength are not sufficient, and
If it exceeds 0% by weight, the fluidity decreases. The film-forming material is necessary when the adhesive is formed into a film, but may not be used in the form of varnish or paste.

The radical-curable adhesive contains a radically polymerizable compound and a polymerization initiator, and preferably forms a film when forming a film. The radical polymerizable compound is a compound having a functional group polymerizable by a radical, and includes (meth) acrylate resin, maleimide resin, citraconic imide resin, nadimide resin, and the like, and two or more kinds may be used as a mixture. The radically polymerizable compound can be used in any state of a monomer and an oligomer, and a mixture of the monomer and the oligomer may be used. The (meth) acrylate resin is obtained by radical polymerization of (meth) acrylate, and the (meth) acrylate is methyl (meth) acrylate.
Acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, ethylene glycol di (meth) acrylate,
Diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-
Bis [4- (acryloxymethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) phenyl] propane, dicyclopentenyl (meth) acrylate, tricyclodecanyl (meth) acrylate, tris (acrylic) Roxyethyl) isocyanurate, urethane (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, and the like.
More than one kind may be mixed and used. If necessary, a radical polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used within a range where the curability is not impaired.

Further, when a phosphate compound is used as the radical polymerizable compound, the adhesive strength to inorganic substances such as metals can be improved. The amount of the phosphate compound used is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. The phosphate compound is obtained as a reaction product of phosphoric anhydride and 2-hydroxyethyl (meth) acrylate. Specifically, there are mono (2-methacryloyloxyethyl) acid phosphate, di (2-methacryloyloxyethyl) acid phosphate and the like, and these may be used alone or in combination.

The maleimide resin has at least one maleimide group in the molecule. Examples thereof include phenylmaleimide, 1-methyl-2,4-bismaleimidebenzene, and N, N'-m-phenylenebis. Maleimide, N,
N'-p-phenylene bismaleimide, N, N'-4,4-biphenylene bismaleimide, N, N'-4,4- (3,3-
Dimethylbiphenylene) bismaleimide, N, N'-4,4
-(3,3-dimethyldiphenylmethane) bismaleimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bismaleimide, N, N'-4,4-diphenylmethanebismaleimide, N, N'- 4,4-diphenylpropanebismaleimide, N, N'-4,4-diphenyletherbismaleimide, N, N'-4,4-diphenylsulfonebismaleimide, 2,2-bis (4- (4-maleimidophenoxy) Phenyl) propane, 2,2-bis (3-s-butyl-3,4- (4-maleimidophenoxy) phenyl) propane, 1,1-bis (4- (4-maleimidophenoxy) phenyl) decane, 4'-cyclohexylidene-bis (1- (4-maleimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-maleimidopheno) Xy) phenyl) hexafluoropropane, etc., and may be used alone or as a mixture of two or more.

The citraconic imide resin is obtained by polymerizing a citraconic imide compound having at least one citraconic imide group in a molecule. Examples of the citraconic imide compound include phenylcitraconic imide and 1-methyl-2. , 4-biscitraconimidobenzene, N, N'-m-phenylenebiscitraconimide, N, N '
-P-phenylenebiscitraconimide, N, N'-4,4
-Biphenylenebiscitraconimide, N, N'-4,4-
(3,3-dimethylbiphenylene) biscitraconimide, N, N'-4,4- (3,3-dimethyldiphenylmethane) biscitraconimide, N, N'-4,4- (3,3-
Diethyldiphenylmethane) biscitraconimide, N,
N'-4,4-diphenylmethanebiscitraconimide,
N, N'-4,4-diphenylpropanebiscitraconimide, N, N'-4,4-diphenyletherbiscitraconimide, N, N'-4,4-diphenylsulfonebiscitraconimide, 2,2-bis ( 4- (4-citraconimidophenoxy) phenyl) propane, 2,2-bis (3
-S-butyl-3,4- (4-citraconimidophenoxy) phenyl) propane, 1,1-bis (4- (4-
Citraconic imidophenoxy) phenyl) decane, 4,
4′-cyclohexylidene-bis (1- (4-citraconimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-citraconimidophenoxy) phenyl) hexafluoropropane, and the like, They may be used alone or in combination of two or more.

The nadimide resin is obtained by polymerizing a nadimide compound having at least one nadimide group in a molecule. Examples of the nadimide compound include:
Phenylnadiimide, 1-methyl-2,4-bisnadiimidebenzene, N, N'-m-phenylenebisnadiimide,
N, N'-p-phenylenebisnadimide, N, N'-4,4-
Biphenylene bisnadiimide, N, N'-4,4- (3,3
-Dimethylbiphenylene) bisnadiimide, N, N'-4,
4- (3,3-dimethyldiphenylmethane) bisnadiimide, N, N'-4,4- (3,3-diethyldiphenylmethane) bisnadiimide, N, N'-4,4-diphenylmethanebisnadiimide, N, N'-4 , 4-Diphenylpropanebisnadimide, N, N'-4,4-diphenyletherbisnadimide, N, N'-4,4-diphenylsulfonebisnadimide, 2,2-bis (4- (4-nadiimidophenoxy) Phenyl) propane, 2,2-bis (3-s-
Butyl-3,4- (4-nadiimidophenoxy) phenyl) propane, 1,1-bis (4- (4-nadiimidophenoxy) phenyl) decane, 4,4′-cyclohexylidene-bis (1- ( There are 4-nadiimidophenoxy) phenoxy) -2-cyclohexylbenzene, 2,2-bis (4- (4-nadiimidophenoxy) phenyl) hexafluoropropane and the like. Is also good.

When the radical polymerizable compound is used, a polymerization initiator is used. The polymerization initiator is not particularly limited as long as it is a compound that generates a radical by light or heating, and includes a peroxide, an azo compound, and the like, and appropriately takes into consideration the intended connection temperature, connection time, storage stability, and the like. From the viewpoints of high reactivity and storage stability, an organic peroxide having a half-life of 10 hours at a temperature of 40 ° C. or more and a half-life of 1 minute of 180 ° C. or less is preferable.
An organic peroxide having a temperature of 0 hours of 50 ° C. or more and a half-life of 1 minute of 170 ° C. or less is particularly preferred. When the connection time is 10 seconds, the amount of the polymerization initiator to obtain a sufficient reaction rate is preferably 1 to 20% by weight, and 2 to 15% by weight.
% By weight is particularly preferred. Specific compounds of the organic peroxide used can be selected from diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide, etc. Oxyesters, dialkyl peroxides,
Hydroperoxides and silyl peroxides are particularly preferable because the amount of chlorine ions and organic acids in the initiator is 5,000 ppm or less, the amount of organic acids generated after decomposition is small, and the corrosion of the electrode can be suppressed.

Examples of the diacyl peroxides include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, and succinic. Peroxide, benzoylperoxytoluene, benzoyl peroxide and the like.

The peroxydicarbonates include di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-carbonate.
Ethoxymethoxyperoxydicarbonate, di (2-
Ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-
3-methoxybutylperoxy) dicarbonate.

Examples of peroxy esters include cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxynodecanoate. , T-hexylperoxy neodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, 2,
5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanonate, t-hexylperoxy-2-ethylhexano Tert-butylperoxy-2-ethylhexanonate, t-butylperoxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxyisobutyrate Butylperoxy-3,5,5-trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-
Di (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-
Hexyl peroxy benzoate, t-butyl peroxy acetate and the like can be mentioned.

The 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, 2,2
-Bis (t-butylperoxy) decane and the like.

In the dialkyl peroxides, α,
α'-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-
Examples thereof include 2,5-di (t-butylperoxy) hexane and t-butylcumyl peroxide.

Examples of the hydroperoxides include diisopropylbenzene hydroperoxide, cumene hydroperoxide and the like.

Examples of the silyl peroxides include t-butyltrimethylsilyl peroxide, bis (t-butyl) dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, and tris ( (t-butyl) vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) diallylsilyl peroxide, tris (t-butyl) allylsilyl peroxide and the like.

Further, in order to suppress corrosion of the electrode, the content of chlorine ions and organic acids contained in the curing agent is preferably 5,000 ppm or less, and more preferably, the amount of organic acids generated after thermal decomposition is small. Further, since the stability of the produced adhesive is improved, it is preferable that the adhesive has a weight retention of 20% by weight or more after being left open at room temperature (25 ° C.) and normal pressure for 24 hours. These can be used by appropriately mixing. These free radical generators can be used alone or as a mixture, and a decomposition accelerator, an inhibitor and the like may be used as a mixture. Further, those in which these free radical generators are coated with a polyurethane-based or polyester-based polymer substance and microencapsulated are preferable because the pot life is extended.

The film forming material is the same as described above. In addition to the radical polymerizable compound, the above-mentioned epoxy resin can be blended as a thermosetting resin. These epoxy resins may be used in combination of two or more. Examples of the curing agent for this epoxy resin include those used as ordinary curing agents for epoxy resins, such as amines, phenols, acid anhydrides, imidazoles, and dicyandiamide. Further, tertiary amines and organic phosphorus compounds generally used as a curing accelerator may be appropriately used. As a method of reacting an epoxy resin, cationic polymerization may be performed using a sulfonium salt, an iodonium salt, or the like, instead of using the above-mentioned curing agent.

The photocurable adhesive preferably contains a photocationically polymerizable compound, mainly a polymerization initiator that generates a cationic species by light irradiation or heating containing a wavelength component of 180 to 750 nm. The photocationically polymerizable compound is selected from one or more of an epoxy compound, a vinyl ether compound, an oxetane compound, and a cyclic ether compound. Mainly 1
At least one selected from aromatic sulfonium salts, iodonium salts, iron-arene complexes, aromatic sulfonium salts, aliphatic sulfonium salts, and the like, as a polymerization initiator that generates a cationic species by light irradiation or heating containing a wavelength component of 80 to 750 nm. It is a kind. Mainly 180-750nm
The polymerization initiator that generates a cationic species by light irradiation containing a wavelength component of is mainly a polymerization initiator that generates a cationic species by light irradiation containing a wavelength component of 180 to 750 nm, and refers to the cationic species generated by light irradiation. However, it may include cation species generated by heating, meaning that there are many cation species generated by light irradiation. Also,
The polymerization initiator that mainly generates a cationic species by heating is a polymerization initiator that mainly generates a cationic species by heating, and refers to a cationic species generated by heating, but may include a cationic species generated by light irradiation, This means that there are many cation species generated by heating. The photocationically polymerizable compound is a compound having a functional group that is polymerized mainly by light irradiation containing a wavelength component of 180 to 750 nm or a cation species generated mainly by heating, such as an epoxy compound, a vinyl ether compound, an oxetane compound and And cyclic ether compounds.

The epoxy compound is not particularly limited as long as it has two or more epoxy groups in one molecule.
Known ones can be used. For example, bisphenol type epoxy resin derived from epichlorohydrin and bisphenol A or bisphenol F, polyglycidyl ether, polyglycidyl ester, aromatic epoxy compound, alicyclic epoxy compound, cresol novolak type epoxy resin, phenol novolak type epoxy resin Novolak type epoxy compounds, glycidylamine epoxy compounds, glycidyl ester epoxy compounds, biphenyl diglycidyl ether, triglycidyl isocyanurate, polyglycidyl methacrylate, copolymerization of glycidyl methacrylate with a copolymerizable vinyl monomer Coalescence and the like. These are used alone or in combination of two or more.

Examples of the vinyl ether compound include an alkyl vinyl ether compound, an alkenyl vinyl ether compound, an alkynyl vinyl ether compound, an aryl vinyl ether compound and the like.

The oxetane compound includes oxetane alcohol, aliphatic oxetane compound, aromatic oxetane compound and the like. As the cyclic ether compound,
Examples thereof include a tetrahydrofuran compound and a tetrahydropyran compound. Among them, epoxy compounds are preferred because grades having different molecular weights are widely available as compared with other compounds, and adhesiveness, reactivity, curing characteristics and the like can be arbitrarily set.

The content of the cationic photopolymerizable compound is preferably 10 to 90% by weight, more preferably 25 to 75% by weight, based on the whole adhesive. When the content is less than 10% by weight, only an adhesive having poor physical properties of the cured product can be obtained, and when the content exceeds 90% by weight, for example, when a cationic photopolymerizable compound having a large curing shrinkage is used. However, it becomes difficult to use a method of alleviating this with other components.

The epoxy equivalent of the epoxy compound is 43 to
1000 is preferable, 50 to 800 are more preferable, and 7
3-600 is especially preferable. If the epoxy equivalent is less than 43 or more than 1000, the adhesive strength tends to decrease when connecting the electrodes. These epoxy compounds can remove impurity ions (Na ⁺ , Cl ^−, etc.) and hydrolyzable chlorine
It is preferable to use a high-purity product reduced to 0 ppm or less in order to prevent electron migration.

Examples of the polymerization initiator that mainly generates a cationic species by irradiation with light containing a wavelength component of 180 to 750 nm, and the polymerization initiator that mainly generates a cationic species by heating include aromatic diazonium salts, aromatic sulfonium salts, and the like. Use of onium salts such as aliphatic sulfonium salts, aromatic iodonium salts, phosphonium salts, pyridinium salts, selenonium salts, complex compounds such as metal arene complexes, silanol / aluminum complexes, benzoin tosylate, o-nitrobenzyl tosylate, etc. Can be. Further, as a counter anion when forming a salt, hexafluoroantimonate, hexafluorophosphate, tetrafluoroborate, tetrakis (pentafluorophenyl) borate and the like are preferably used in terms of reactivity. As the polymerization initiator mainly generating a cationic species by heating, a compound having a low thermocatalytic activity at a temperature of 100 ° C. or lower is preferable in terms of enhancing the storage stability of the adhesive. In addition, mainly 180-750
A polymerization initiator that generates a cationic species by light irradiation containing a wavelength component of nm has the same thermal activity as a polymerization initiator that generates a cationic species mainly by heating, or conversely, mainly by heating When the polymerization initiator that generates a cationic species is a compound having the same photoactivity as the polymerization initiator that generates a cationic species by light irradiation mainly containing a wavelength component of 180 to 750 nm, It is preferable in that the reactivity is improved.

As the polymerization initiator for generating a cationic species by irradiation mainly with light having a wavelength component of 180 to 750 nm, a compound containing one or more aromatic rings in the molecule is preferable, and bis [4- (diphenylsulfo) Nio) -phenyl] sulfide-bis-hexafluorophosphate,
Bis [4-di (4- (2-hydroxyethyl) phenyl) sulfonio-phenyl] sulfide bis-hexafluorophosphate, bis [4-di (4- (2-hydroxyethyl) phenyl) sulfonio-phenyl] sulfidebis- Aromatic sulfonium salts such as hexafluoroantimonate and η-5,2,4- (cyclopentadienyl) [(1,2,3,4,5,6-η)-(methylethyl) -benzene]- Iron (II) hexafluorophosphate, (tolylcumyl) iodonium tetrakis (pentafluorophenyl) borate, diallyliodonium hexafluoroantimonate and mixtures thereof can be used, and ADEKA OPTOMER SP-150;
Adeka Optomer SP-170 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), Cyracure UVI-6990 (trade name, manufactured by Union Carbide Co., Ltd.), Sun Aid SI-60L, Sun Aid SI-80L, Sun Aid SI-100L (Sanshin Chemical Co. Company name), Irgacure 261 (Ciba Specialty Chemicals)
micals), RHODORSIL PHOTOINITIATOR20
These compounds and their solutions can be used as commercial products such as 74 (trade name, manufactured by Rhodia Japan).

Compounds such as aromatic sulfonium salts, aliphatic sulfonium salts and dialkylphenacyl sulfonium salts are preferably used as polymerization initiators which mainly generate cationic species by heating, and include San Aid SI-60L and San Aid SI- 80L, San-Aid SI-100L (trade name, manufactured by Sanshin Chemical Industry Co., Ltd.), Adeka Opton CP-6
6. These compounds and their solutions can be used as commercial products such as Adeka Opton CP-77 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) and CI-2624 (trade name, manufactured by Nippon Soda Co., Ltd.).

A polymerization initiator which generates a cationic species by irradiation with light containing a wavelength component of mainly 180 to 750 nm;
When a polymerization initiator that mainly generates a cationic species by heating is used, the amount of each is preferably 0.05 to 30% by weight based on 100% by weight of the photocationically polymerizable compound. 0.1 to 15% by weight, particularly preferably 0.5 to 10% by weight. If the amount is less than 0.05% by weight, the effect of promoting the curing tends to be insufficient, and if it exceeds 30% by weight, the compatibility tends to decrease.

The weight ratio of the content of the polymerization initiator that generates a cationic species by light irradiation mainly containing a wavelength component of 180 to 750 nm and the content of the polymerization initiator that mainly generates a cationic species by heating is as follows: It is preferably 1/50 to 50/1. When the ratio is out of this range, the content of the other polymerization initiator becomes extremely small, so that a sufficiently cured product may not be obtained.

A polymerization initiator that generates a cationic species by irradiation with light containing a wavelength component of mainly 180 to 750 nm;
When a polymerization initiator that generates a cationic species mainly by heating is used, each of them can be used alone or in combination. Further, in order to promote cationic polymerization and enhance the curability of the adhesive, a photosensitizer may be appropriately used in combination. The photosensitizer is not particularly limited as long as it is for effectively utilizing the absorption wavelength of the excitation light to be used, and known compounds can be used. Specifically, anthracene, phenothiazine And compounds such as perylene, carbazole, benzophenone, thioxanthone, fluorenone, anthraquinone, and derivatives thereof.

A film forming material may be further added to the adhesive. The amount used is preferably 20 to 320 parts by weight based on 100 parts by weight of the cationic photopolymerizable compound. If this amount is less than 20 parts by weight or 32
If it exceeds 0 parts by weight, the film-forming properties tend to decrease.

The thermoplastic adhesive (hot melt) is basically composed of a polymer which gives an ordinary cohesive force showing an insulating property,
Other tackifiers used as needed, tackifiers,
It is preferable to include a crosslinking agent, an antioxidant, a dispersant, and the like. These polymer species include ethylene-vinyl acetate copolymer, modified ethylene-vinyl acetate copolymer, polyethylene, ethylene-propylene copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene -Acrylate copolymer, acrylate rubber, polyisobutylene, atactic polypropylene,
Polyvinyl butyral, acrylonitrile-butadiene copolymer, styrene-butadiene block copolymer, styrene-isoprene block copolymer, polybutadiene, ethylene cellulose, polyester, polyamide,
Polyurethane, natural rubber, silicone rubber, synthetic rubbers such as polychloroprene, polyvinyl ether, and the like are applicable, and may be used alone or in combination of two or more.

Examples of the tackifier include dicyclopentadiene resin, rosin, modified rosin, terpene resin, xylene resin, terpene-phenol resin, alkylphenol resin, cumarone-indene resin and the like. These may be used alone or as needed. Used in combination of two or more. Representative examples of the tackifier include various plasticizers such as dioctyl phthalate. The crosslinking agent is used when it is necessary to increase the cohesive strength of the polymer, and is a polyfunctional substance that reacts with the functional group of the polymer, and examples thereof include polyisocyanate, melamine resin, urea resin, and phenol resin. Anti-aging agents are used when it is necessary to enhance the stability of the polymer binder against heat, oxygen, light, etc., and include, for example, stabilizers such as metal soaps, antioxidants such as alkylphenols, and benzophenone. And benzotriazole-based ultraviolet absorbers.
Used in combination of more than one species. The dispersant may be used to improve the dispersibility of the particles. Examples of the dispersant include a surfactant, and one or more of nonionic, cationic, anionic, and amphoteric are used in combination. be able to.

The adhesive may optionally contain a filler, a softener, an accelerator, an antioxidant, a coloring agent, a flame retardant, and a coupling agent.

The circuit connecting member used in the present invention may have a multilayer structure composed of two or more layers having a Tg (glass transition temperature) of 5 ° C. or more when cured to form a cured product. The substrate to be adhered using the circuit connecting member of the present invention is not particularly limited as long as electrodes requiring electrical connection are formed. There are a glass or plastic substrate on which electrodes are formed, a printed wiring board, a ceramic wiring board, a flexible wiring board, a semiconductor silicon chip, and the like, which are used in combination as necessary. The conditions for connection are not particularly limited, but the connection temperature is 90 to 250 ° C., the connection time is 1 second to 10 minutes, and is appropriately selected depending on the use application, the adhesive, and the substrate, and if necessary, post-curing. May be performed. The connection is performed by heating and pressurizing, but energy other than heat, such as light, ultrasonic waves, and electromagnetic waves, may be used as necessary.

[0051]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. (Preparation of Surface Treated Particle A) In the polyphthalide of the formula (1), R = biphenyl, R ₁ = H, X = O, Y = SO ₂
In a 1% by weight dimethylformamide solution of poly (4,4-diphenylene sulfophthalide), a nickel layer having a thickness of 0.2 μm is provided on the surface of particles having polystyrene nuclei. The conductive particles having an average particle size of 4 μm provided with a gold layer having a thickness of 0.04 μm were added, and the mixture was stirred at room temperature (25 ° C.) for 10 minutes. After filtering the conductive particles,
After drying at 120 ° C. for 15 minutes, surface-treated particles A (surface-coated conductive particles A) were obtained. (Preparation of Surface Treated Particles B) Nickel particles having an average particle size of 5 μm were added to a 3% by weight chloroform solution of the same polyphthalide as described above, and the surface of the particles having polystyrene nuclei was added.
Stirred at 25 ° C. for 30 minutes. After filtering the conductive particles, 80
After drying at 5 ° C. for 5 minutes, surface-treated particles B (surface-coated conductive particles B) were obtained. (Preparation of Surface Treated Particle C) A nickel layer having a thickness of 0.2 μm was provided on the surface of particles having polystyrene as a core in a 0.1% by weight cyclohexanone solution of polyphthalide as described above. Add conductive particles having an average particle size of 5 μm provided with a gold layer having a thickness of 0.04 μm,
For 30 minutes. After the conductive particles were separated by filtration, they were dried at 150 ° C. for 10 minutes to obtain surface-treated particles C (surface-coated conductive particles C).

(Preparation of surface-treated particles D) 5% by weight of γ-aminopropyltrimethoxysilane was added to a 1% by weight solution of polyphthalide in cyclohexanone similar to the above, and the surface of the particles having a polystyrene nucleus having a thickness of 0.1% was added. 2 μm
And a conductive layer having an average particle size of 4 μm provided with a gold layer having a thickness of 0.04 μm was added to the outside of the nickel layer and stirred at room temperature (25 ° C.) for 30 minutes. After the conductive particles were separated by filtration, they were dried at 150 ° C. for 5 minutes to obtain surface-treated particles D (surface-coated conductive particles D).

Using these surface-treated particles (surface-coated conductive particles) A, B, C, and D, a film was prepared with the following composition.

Example 1 Phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name PKHC, average molecular weight: 45,000) 50 g Microcapsule latent curing agent (HX3941HP, trade name, manufactured by Asahi Kasei Epoxy Co., Ltd., thermal activation temperature: 120 ° C.) , DSC peak temperature, microcapsule latent curing agent dispersed in liquid epoxy resin) 48 g γ-glycidoxypropyltrimethoxysilane 2 g mixed solvent of toluene and ethyl acetate (weight ratio 50/5)
0) was dissolved and blended as a solvent, and the surface-treated particles A were further blended and dispersed at 3% by volume. An 80 μm-thick polyethylene terephthalate film having one surface treated on one side is applied using a coating device, dried at 70 ° C. for 10 minutes, and then 30 μm in thickness.
m connection members for circuits were obtained.

(Example 2) Phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name: PKHC, average molecular weight: 45,000) 40 g acrylic rubber 10 g microcapsule-type latent curing agent (HX3941HP, trade name, manufactured by Asahi Kasei Epoxy Co., Ltd.) (Activity temperature: 120 ° C., DSC peak temperature, microcapsule latent curing agent dispersed in liquid epoxy resin) 48 g γ-glycidoxypropyltrimethoxysilane: 2 g mixed solvent of toluene and ethyl acetate (weight ratio: 50/5)
0) as a solvent was dissolved and compounded, and 3% by volume of surface-treated particles B were further mixed and dispersed. An 80 μm-thick polyethylene terephthalate film having one surface treated on one side is applied using a coating device, dried at 70 ° C. for 10 minutes, and then 30 μm in thickness.
m connection members for circuits were obtained.

Example 3 Phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name: PKHC, average molecular weight: 45,000) 50 g Isocyanuric acid ethylene oxide-modified diacrylate 46 g Phosphate ester acrylate 4 g 2,5-dimethyl-2,5 3 g of -bis (2-ethylhexanoylperoxy) hexane was dissolved and mixed with methyl ethyl ketone as a solvent, and 3% by volume of surface-treated particles C were further mixed and dispersed. 80μm thick
Was coated on a polyethylene terephthalate film having one surface treated using a coating device, and dried at 70 ° C. for 10 minutes to obtain a 30 μm thick circuit connecting member.

Example 4 Phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name: PKHC, average molecular weight: 45,000) 25 g polyurethane resin 25 g dicyclohexyl methacrylate 48 g phosphate ester acrylate 2 g 2,5-dimethyl-2,5- 3 g of bis (2-ethylhexanoylperoxy) hexane was dissolved and mixed with methyl ethyl ketone as a solvent, and 3% by volume of surface-treated particles D were further mixed and dispersed. 80μm thick
Was coated on a polyethylene terephthalate film having one surface treated using a coating device, and dried at 70 ° C. for 10 minutes to obtain a 30 μm thick circuit connecting member.

(Comparative Examples 1 to 4) A circuit was prepared in the same manner as in Examples 1 to 4, except that untreated conductive particles before treatment were used instead of the surface-treated particles in the formulations of Examples 1 to 4. Connection members were obtained.

Comparative Example 5 Conductive particles having an average particle size of 4 μm in which a nickel layer having a thickness of 0.2 μm was provided on the surface of particles having polystyrene nuclei and a gold layer having a thickness of 0.04 μm was provided outside the nickel layer. An insulating surface layer made of a styrene-butadiene copolymer was formed with a thickness of about 1 μm on the outermost surface of. A circuit connecting member was obtained in the same manner as in Example 1 except that the above particles were used instead of the surface-treated particles A of Example 1.

(Preparation of Circuit Connection Structure) The circuit connection member was slit to a width of 1.5 mm, and ITO was used as an electrode.
80 ° C, 5 seconds, 1MPa
Temporarily connected under the following conditions. The surface-treated polyethylene terephthalate film was peeled off, and the bump area was 50 μm.
The electrodes of the semiconductor chip on which gold bumps of mx50 μm, pitch 100 μm, and height 20 μm were formed were aligned and placed.
Under the connection conditions of 5 seconds and 3 MPa, and in Examples 3 and 4 and Comparative Examples 3 and 4, the main connection was performed at 160 ° C. for 10 seconds and 3 MPa to obtain a circuit connection structure. 1 in each of Examples and Comparative Examples
0 samples were prepared.

(Characteristic evaluation method) Connection resistance: Using a multimeter TR6848 manufactured by Advantest Co., Ltd.
The connection resistance was measured by the terminal method. In addition, these samples were left in a constant temperature and humidity tester at 85 ° C. and 85% RH for 500 hours, and then the connection resistance was measured. The connection resistance value is
The average value of 10 samples was used. Insulation resistance: The insulation resistance between horizontal circuits was measured using the above circuit connection structure. The measurement was performed for 10 samples and calculated as a short-circuit occurrence rate. The results are summarized in Table 1.

[0062]

[Table 1]

In Examples 1 to 4 of the present invention, the surface-coated conductive particles in which the concentration of the material for coating the conductive particles is changed from 0.1% by weight to 1% by weight are used. Both have low connection resistance and are good, and the short-circuit occurrence rate is 0%.
Is good. On the other hand, in Comparative Examples 1 to 4 in which the surface-coated conductive particles were not used, the connection resistance was small and good, but a short circuit occurred and the insulating property could not be secured. In Comparative Example 5, the connection resistance was high because the surface layer was insulative.

[0064]

According to the present invention, it is possible to achieve a connection in which both the connection resistance and the insulating property are compatible.

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 4J037 AA02 AA04 AA29 CA02 CA03                       CC21 DD13 DD23 EE03 EE04                       FF11                 4J040 DA021 DA051 DA121 DD051                       DF041 DF051 DG001 EC001                       EE021 EH022 EH031 EJ002                       EL032 HA026 HA066 HA076                       JB01 JB02 JB08 JB09 KA03                       KA07 KA32 LA09 NA20 PA32                       PA33                 5G307 AA08

Claims (5)

[Claims] 1. Surface-coated conductive particles having conductive particles coated with a composition containing a pressure-sensitive conductive polymer. 2. The pressure-sensitive conductive polymer is represented by the formula (I):
The surface-coated conductive particles according to claim 1, which is a polyphthalide.
Child. Embedded image (In the formula (1), R represents a divalent aromatic hydrocarbon group or
A divalent heterocyclic-containing aromatic group;₁Is hydrogen, alk
Group, fluorinated alkyl group, alkoxy group or halogen
This may be a plurality (2-4), and X
Is O or NR ₃(However, R₃Indicates the next group
You. ) And Y is SO₂Or CO and n is
Indicates the number of repeating units in Lima. ) Embedded image 3. A circuit connecting member comprising an insulating adhesive having a fluidity upon heating and coated particles having conductive particles covered with an insulating substance, wherein the coated particles are formed of a material. A connection member for a circuit, which is the surface-coated conductive particle according to 1. 4. A connection method in which a circuit connecting member is interposed between substrates having opposing circuit electrodes, and the substrates having opposing circuit electrodes are pressed to electrically connect the electrodes in the pressing direction. A circuit connection method, wherein the circuit connection member is the circuit connection member according to claim 3. 5. A connection structure in which a circuit connecting member is interposed between substrates having opposing circuit electrodes, and the substrates having opposing circuit electrodes are pressed to electrically connect the electrodes in the pressing direction. A circuit connection structure, wherein the circuit connection member is the circuit connection member according to claim 3.