JP2002164389A - Film-like adhesive for connecting circuit, connecting structure of circuit terminal, and method for connecting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film-like adhesive for connecting a circuit, capable of connecting in a short time and having superior adhesive properties, connecting reliability and storage stability, and connecting structure of a circuit terminal, and to provide a method for connecting the circuit terminal. SOLUTION: The film-like adhesive for connecting the circuit is interposed between opposed circuit electrodes to electrically connect between the electrodes in pressurizing direction, by heating and pressurizing the opposed electrodes. The adhesive comprises (1) an acrylate compound, having two or more radical polymerizable functions, (2) a thermoplastic resin having a melt viscosity at a glass transition temperature of 50 to 150 deg.C of 10,000 Pa.s or less, (3) an organic peroxide, and (4) a silane coupling agent, having a radical polymerizable functional group as indispensable components so that a heating start temperature is 100 to 150 deg.C. The method for connecting the circuit terminal comprises the steps of disposing a first circuit material having a first connection terminal, and a second circuit material having a second connection terminal so that the first terminal is made oppose the second terminal; making the film-like adhesive for connecting the circuit to be interposed between the first terminal and second terminal disposed opposite; and electrically connecting the first terminal disposed opposite to second terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film-like adhesive for circuit connection, which is interposed between opposing circuit electrodes, presses the opposing circuit electrodes, and electrically connects the electrodes in the pressing direction. The present invention relates to a terminal connection structure and a circuit terminal connection method.

[0002]

2. Description of the Related Art Epoxy resin adhesives have high adhesive strength and are excellent in water resistance and heat resistance.
It is widely used for various purposes such as electronics, architecture, automobiles, aircraft, etc. Among them, one-pack type epoxy resin-based adhesives are used in the form of a film, paste, or powder because they do not require mixing of a main agent and a curing agent and are easy to use. In this case, it is general to obtain a specific performance by various combinations of an epoxy resin, a curing agent and a modifying agent (for example, JP-A-62-141083).
However, although an epoxy resin film adhesive as disclosed in JP-A-62-141083 is excellent in workability, it has a connection time of about 20 to 140 to 140 to 1 in connection time.
Heating at about 80 ° C. and heating at about 180 to 210 ° C. for 10 seconds were required. The reason for this is that, in order to obtain a balance between short-time curability (rapid curability) and storage stability (preservability), a sufficient reaction cannot be obtained at the time of curing using a catalytic curing agent that is inactive at room temperature.

In recent years, in the field of precision electronic equipment, the density of circuits has been increased, the electrode width and the electrode interval have become extremely narrow, and the expansion of the circuit board due to heat during circuit connection has caused the displacement of the connection terminals. May be affected. In particular, in the connection between LCD (liquid crystal display) and TCP (tape carrier package) in the field of liquid crystal panels, and the connection between TCP and PWB (printed circuit board), conventional wiring is required for finer wiring and larger panels. Under the connection condition of the film-like adhesive for circuit connection using an epoxy resin system, there was a problem that the wiring was dropped, peeled off or displaced due to elongation of TCP due to heat at the time of connection. For this reason, radically polymerizable adhesives have been developed as low-temperature and fast-curing connection materials instead of epoxy resin-based adhesives (for example, Japanese Patent Application Laid-Open No. H11-28402).
No. 5, JP-A-2000-44905). JP-A-11-284025 and JP-A-2000-449
No. 05, a radical polymerizable adhesive is prepared by mixing a monomer such as an acrylate compound, a methacrylate compound or a maleimide compound with a radical generating material such as a peroxide as a radical polymerizable material, The monomer is radically polymerized and cured by radicals generated from the product. It is characterized in that curing at a low temperature is possible by selecting a substance having a low radical generation temperature of the radical generating substance.
Connection is possible with a heating temperature of about 10 ° C. and a heating time of 10 seconds to 15 seconds. However, in general, a heat-radical polymerizable resin such as an acrylate compound has a weaker adhesive strength than an epoxy resin-based adhesive. For this reason, as disclosed in JP-A-11-284025, a method of improving the adhesive force by a phosphate ester compound,
As disclosed in Japanese Patent Application Publication No. 000-44905, means for improving the adhesive force by mixing a phosphate ester compound and an epoxysilane coupling agent has been proposed.

On the other hand, in the field of liquid crystal panels, a COG (Chip on Glass) connection method in which a driver IC is directly connected to an LCD is used for 10 seconds or less and 5 seconds or less for the purpose of improving production efficiency.
There is a demand for a connection in a short time of less than a second. In the COG connection method, the thermal expansion coefficient of the glass that is the liquid crystal panel and the driver
Since the thermal expansion coefficient of a silicon chip as an IC is close and the problem of displacement caused by heating is small, it is possible to cope with a demand for shortening the connection time by increasing the connection temperature. However, an epoxy resin adhesive as disclosed in JP-A-62-141083 has a temperature of 230 ° C.
Even at the above heating temperature, the curing reaction does not proceed sufficiently for 5 seconds or less, so that the adhesive strength is low and the connection reliability is reduced. On the other hand, with regard to radically polymerizable adhesives as disclosed in JP-A-11-284025 and JP-A-2000-44905, although the curing speed is higher than that of epoxy resin-based adhesives, phosphate ester or phosphate ester is used. Even when the adhesive force is increased with the epoxysilane coupling agent, the adhesive force is insufficient. This is probably because the stress generated when the chip and the LCD are bonded is larger than when the TAB and the LCD are bonded. Furthermore, in order to react in a short time, it is necessary to use a highly reactive monomer, but in general, when a highly reactive monomer is used, the reaction proceeds even in a storage environment such as room temperature. In addition, a sufficient connection reliability cannot be obtained due to a decrease in the fluidity and adhesiveness of the resin. Therefore, there is a demand for a film-like adhesive for circuit connection that can be connected in a shorter time and has good storage stability.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a short-time connection is possible in electrical connection between fine circuits of precision electronic equipment, particularly in COG connection between an LCD panel and a driver IC.
It is another object of the present invention to provide a film-like adhesive for circuit connection which is excellent in adhesiveness, connection reliability and storage stability, a connection structure of circuit terminals, and a method of connecting circuit terminals.

[0006]

The film-like adhesive for circuit connection of the present invention is interposed between opposing circuit electrodes, and heats and presses the opposing circuit electrodes to electrically connect the electrodes in the pressing direction. A film-like adhesive for connecting a circuit,
(1) a radically polymerizable bifunctional or higher acrylate or methacrylate compound; (2) a glass transition temperature of 50 ° C. or higher and a melt viscosity at 150 ° C. of 10,000 Pa
-S or less thermoplastic resin, (3) organic peroxide, (4)
A silane coupling agent having a radical polymerizable functional group is an essential component, and an exothermic onset temperature of 100 ° C. or more, 150
It is a film-like adhesive for circuit connection having a temperature of not more than ° C. Preferably, (1) a radical polymerizable bifunctional or more functional acrylate compound or methacrylate compound is added to 25
100 parts by weight, (2) 100 parts by weight of a thermoplastic resin having a glass transition temperature of 50 ° C. or more and a melt viscosity at 150 ° C. of 10,000 Pa · s or less, and (3) an organic peroxide having two or more radical polymerizable properties. 1 to 20 parts by weight based on 100 parts by weight of the acrylate compound or methacrylate compound,
(4) 5 parts by weight of a silane coupling agent having a radical polymerizable functional group per 100 parts by weight of the total weight of (1) to (3).
It is a film-like adhesive for circuit connection blended in an amount of up to 15 parts by weight. The organic peroxide is preferably a powder (solid) at room temperature (25 ° C.), and has a half-life decomposition temperature of 180 minutes per minute.
° C or lower and a 100-hour half-life decomposition temperature of 4
Those having a temperature of 0 ° C. or higher are preferred. The film adhesive for circuit connection can contain conductive particles.

[0007] In the connection structure for circuit terminals of the present invention, the first circuit member having the first connection terminal and the second circuit member having the second connection terminal are connected to the first connection terminal and the second connection member. The connection terminals are arranged to face each other, and the film-like adhesive for circuit connection is interposed between the first connection terminal and the second connection terminal arranged opposite to each other. One connection terminal and a second connection terminal are electrically connected. The method for connecting circuit terminals of the present invention includes a first circuit member having a first connection terminal, a second circuit member having a second connection terminal, a first connection terminal and a second connection terminal. Are disposed in opposition to each other, and the above-described film connection adhesive for circuit connection is interposed between the first connection terminal and the second connection terminal disposed opposite to each other, and the first connection is disposed by heating and pressing. The terminal is electrically connected to the second connection terminal. At least one surface of the connection terminal is gold, silver,
It can be composed of a metal selected from tin and platinum group.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The film-like adhesive for circuit connection of the present invention is one which flows by heating and pressurizing, and which reacts and cures with an acrylate compound or a methacrylate compound by heating. An adhesive that develops an adhesive force by the coupling effect of the coupling agent and has a heat generation start temperature of 100 ° C. or higher,
It is characterized by being at most 50 ° C. Also,
It is characterized by using a powder (solid) organic peroxide at room temperature (25 ° C.). Exotherm start temperature 100
When the temperature is set to not lower than 150 ° C. and higher, the storage stability is high, and bonding can be performed in a short time by heating at 180 to 210 ° C. When the exothermic onset temperature is lower than 100 ° C., the reactivity increases, but the storage stability decreases, which is not preferable. On the other hand, if the heat generation start temperature is higher than 150 ° C., the curing does not proceed sufficiently when connecting in a short time, and the connection reliability is reduced. The exothermic onset temperature was measured using a differential scanning calorimeter (DSC) at a heating rate of 10 ° C./min.

The organic peroxide used in the present invention is a curing agent that generates radicals by heating, and is used at room temperature (25%).
° C) and a powder (solid) organic peroxide having a half-life decomposition temperature of 180 ° C or less for one minute and a half-life decomposition temperature of 100 hours or more of 40 ° C or more at room temperature. It is possible to obtain a film-like adhesive for circuit connection having high storage stability without decomposition of organic peroxide. Furthermore, in order to compound powder (solid), the acrylate compound, methacrylate compound and silane coupling agent, which are liquid components in the film, are thickened at room temperature. Of the liquid acrylate component and the methacrylate component during storage can be prevented, and the handleability of the film can be further improved. In the case of a liquid organic peroxide, the viscosity of the liquid component in the film may be reduced as compared with the case of a powder, or may be volatilized at the time of forming or storing the film, and the reactivity may be reduced.

The organic peroxide used in the present invention includes:
Diacyl peroxide, peroxydicarbonate,
It can be selected from peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide, silyl peroxide and the like. In addition, in order to suppress corrosion of the connection terminal of the circuit member, the content of chlorine ions and organic acids in the curing agent is preferably 5000 ppm or less, and more preferably, the amount of organic acids generated after thermal decomposition is small. . Specifically, peroxyester,
It is selected from peroxyketals, dialkyl peroxides, hydroperoxides, and silyl peroxides, and more preferably selected from peroxyesters and dialkyl peroxides. The above-mentioned organic oxides can be appropriately mixed and used.

As the peroxyester, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxynodecanoate , T-hexyl peroxy neodecanoate, t-butyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanate,
2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanate, t
-Hexylperoxy-2-ethylhexanonate, t
-Butylperoxy-2-ethylhexanonate, t-
Butyl peroxyisobutyrate, t-butyl peroxymaleic acid, 1,1-bis (t-butyl peroxy)
Cyclohexane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy-3,5,5
-Trimethylhexanonate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di (m-toluoylperoxy) hexane, 2,5-dimethyl-2,5
-Bis (benzoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t
-Hexylperoxybenzoate, t-butylperoxyacetate, bis (t-butylperoxy) isophthalate and the like.

[0012] As a dialkyl peroxide,
Bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,
5-di (t-butylperoxy) hexane, t-butylcumyl peroxide and the like.

As the hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide and the like can be mentioned.

As the diacyl peroxide, isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide , Benzoyl peroxytoluene,
Benzoyl peroxide and the like.

As peroxydicarbonate, di-
n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di (2-ethylhexylperoxy) dicarbonate , Dimethoxybutyl peroxydicarbonate, di (3-methyl-3-
(Methoxybutylperoxy) dicarbonate.

The peroxyketal includes 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.

As silyl peroxide, t-butyltrimethylsilyl peroxide, bis (t-butyl)
Dimethylsilyl peroxide, t-butyltrivinylsilyl peroxide, bis (t-butyl) divinylsilyl peroxide, tris (t-butyl) vinylsilyl peroxide, t-butyltriallylsilyl peroxide, bis (t-butyl) ) Diallylsilyl peroxide, tris (t-butyl) allylsilyl peroxide and the like. These organically modified oxides that generate free radicals can be used alone or as a mixture, and may be used in combination with a decomposition accelerator, an inhibitor and the like. The organic peroxide which is preferably used at room temperature at room temperature as a powder (solid) has a half-life decomposition temperature of 180 ° C. or less for 1 minute in view of high reactivity and pot life, and 100
Organic peroxides having a half-life decomposition temperature of 40 ° C. or higher are preferred. If the decomposition temperature for a half-life of 1 minute is higher than 180 ° C., the amount of radicals generated by heating at the time of connection decreases, and the adhesive strength required for adhesion cannot be obtained, which is not preferable. On the other hand, if the decomposition temperature at the half-life of 100 hours is less than 40 ° C., radicals are generated by the cleavage of the organic peroxide during storage, and the acrylate compound and the methacrylate compound react to lower the fluidity at the time of connection.
Specific examples of such an organic peroxide include t-butylperoxymaleic acid, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, and bis (t-butylperoxy) isophthalate. Can be These organic peroxides can be used alone or in combination,
A decomposition accelerator, an inhibitor and the like may be mixed and used. The compounding amount of the organic peroxide is preferably 1 to 20 parts by weight, more preferably 5 to 10 parts by weight, per 100 parts by weight of the radically polymerizable bifunctional or higher acrylate compound or methacrylate compound. When the amount is less than this range, curing does not proceed sufficiently, and the cohesive strength of the adhesive is reduced and the adhesiveness is poor, and when it is large, the curing is sufficient but the adhesion at the interface of the film adhesive is poor. become.

The radically polymerizable bifunctional or more acrylate compound or methacrylate compound used in the present invention is a substance having a functional group capable of polymerizing by radicals, and these can be used in any state of a monomer or an oligomer. Yes, it is also possible to use monomers and oligomers in combination. Specific examples of the acrylate compound or methacrylate compound include ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, and trimethylolpropane triacrylate. Methylolpropane trimethacrylate, trimethylolpropane triglycidyl ether triacrylate, trimethylolpropane triglycidyl ether trimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, polyethylene Glycol diacrylate, polyethylene glycol dimethacrylate, hexamethylene glycol diacrylate, hexamethylene glycol dimethacrylate,
Polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, butylene glycol dimethacrylate, butylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate,
1,4-butanediol dimethacrylate, 1,5-pentanediol diacrylate, 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, pentaerythritol diacrylate, Pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, ethylene oxide-modified trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane trimethacrylate, tetramethylolmethanetetraacrylate, tetramethylolmethanetetramethacrylate, tetramethylolpropanetetraacrylate, Tetramethylolpropane tetramethacrylate, pentaerythri Litol tetraacrylate, pentaerythritol tetramethacrylate, 2-hydroxy-1,3-diacryloxypropane, 2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis [4- (acryloxymethoxy) phenyl] propane,
2,2-bis [4- (methacryloxymethoxy) phenyl] propane, 2,2-bis (4-acryloxyethoxyphenyl) propane, 2,2-bis (4-methacryloxyethoxyphenyl) propane, 2, 2-bis (4
-Acryloxydiethoxyphenyl) propane, 2,2
-Bis (4-methacryloxydiethoxyphenyl) propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane, Bisphenol A diacrylate, bisphenol A dimethacrylate, bisphenol A diglycidyl ether diacrylate, bisphenol A diglycidyl ether dimethacrylate, tris (acryloyloxyethyl) isocyanurate, tris (methacryloyloxyethyl) isocyanurate urethane diacrylate compound ,
Urethane dimethacrylate compounds and the like can be mentioned. These can be used alone or in combination. If necessary, a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be appropriately used. In addition, it is preferable to have a dicyclopentenyl group and / or a tricyclodecanyl group and / or a triazine ring, since heat resistance is improved.

Examples of the thermoplastic resin having a glass transition temperature of 50 ° C. or higher and a melt viscosity at 150 ° C. of 10,000 Pa · s or lower include polyvinyl butyral resin, polyvinyl formal resin, polyamide resin, polyester resin, phenol resin, and the like. Polymers such as epoxy resins, phenoxy resins, and polyhydroxy polyether resins are used. Among them, fluidity when used for adhesives,
A polyhydroxy polyether resin having a glass transition temperature of 50 ° C. or more is preferably used from the viewpoint of curing shrinkage suppression effect and connection reliability. When the glass transition temperature is lower than 50 ° C., the film formability is reduced, and the tack is increased, so that the handleability is deteriorated and the storage stability is deteriorated, which is not preferable. In addition, the melt viscosity at 150 ° C is 10,000P
If the value is larger than a · s, the fluidity at the time of connection decreases, and the resin between the opposing terminals of the circuit board is insufficiently removed. further,
A polyhydroxy polyether resin having a fluorene skeleton in the molecule is more preferably used. The polyhydroxy polyether resin having a fluorene skeleton in the molecule can be used alone or in a mixture with the above resin. These thermoplastic resins may be modified with a carboxyl group-containing elastomer, an epoxy group-containing elastomer, or a radical polymerizable functional group. In particular, it is preferable to use a mixture with a high-molecular-weight epoxy resin modified with a carboxyl group-containing elastomer since stress is relaxed.

As the silane coupling agent having a radical polymerizable functional group used in the present invention, a silane coupling agent having an acryl group or a methacryl group as a radical polymerizable functional group is used. A silane coupling agent having no radically polymerizable functional group does not form a bond with an adhesive resin, and thus cannot exhibit adhesive strength. Specific examples of the silane coupling agent include (3-acryloxypropyl) methyldimethoxysilane, (3-acryloxypropyl) trimethoxysilane, and (methacryloxymethyl)
Trimethoxysilane, (methacryloxymethyl) triethoxysilane, (3-methacryloxypropyl) methyldimethoxysilane, (3-methacryloxypropyl) trimethoxysilane, (3-methacryloxypropyl) methyldiethoxysilane, (3- (Methacryloxypropyl) triethoxysilane, (3-methacryloxypropyl) tris (methoxyethoxy) silane, and the like. These may be used alone or in combination of two or more. The amount of the silane coupling agent is preferably 5 to 15 parts by weight based on the total weight of the adhesive. If the amount is less than this range, the cohesive strength of the adhesive is reduced and the adhesive strength is inferior.

Further, the film-like adhesive for circuit connection of the present invention is a copolymer acrylic containing one or more of acrylic acid, acrylic acid ester, methacrylic acid ester, acrylonitrile, glycidyl acrylate and glycidyl methacrylate as monomer components. An elastomer such as rubber or polyurethane can be contained. When an elastomer is contained, a stress relaxation effect can be obtained, which is preferable.

Further, it may contain a filler, a softening agent, an accelerator, an antioxidant, a coloring agent, a flame retardant, a thixotropic agent, a phenol resin, a melamine resin, isocyanates and the like. It is preferable to include a filler, because an improvement in connection reliability and the like can be obtained.

The film-like adhesive for circuit connection of the present invention can be connected by direct contact of opposing circuit electrodes at the time of connection even without conductive particles, but more stable when the conductive particles are contained. Connection is obtained. Examples of the conductive particles include metal particles such as Au, Ag, Ni, Cu, and solder, and carbon. In order to obtain a sufficient pot life,
The surface layer is made of Au, A instead of transition metals such as Ni and Cu.
g, platinum group noble metals are preferred, and Au is more preferred.
Further, the surface of a transition metal such as Ni may be coated with a noble metal such as Au. Further, a non-conductive glass, ceramic, plastic, or the like may be formed by coating the above metal with a coating or the like, and the outermost layer may be coated with a noble metal.
When plastic is used as the core or when hot-melted metal particles are used as the core, it has deformability due to heating and pressing, so the contact area with the electrode increases during connection, and variations in electrode height are absorbed, improving reliability. Is preferred. The thickness of the noble metals coating layer is preferably 100 Å or more in order to obtain good resistance. However, in the case where a layer of a noble metal is provided on a transition metal such as Ni, when the transition metal is exposed to the surface due to a defect of the noble metal layer or a defect of the noble metal layer generated at the time of mixing and dispersing the conductive particles, the oxidation-reduction effect is obtained. Free radicals are generated in the solution, causing a decrease in storage stability.
Angstrom or more is preferred. The conductive particles are properly used in a range of 0.1 to 30 parts by volume based on 100 parts by volume of the adhesive resin component. In order to prevent a short circuit in an adjacent circuit due to excessive conductive particles, the content is preferably 0.1 to 10 parts by volume.

The film adhesive for circuit connection is divided into two or more layers, and a layer containing an organic peroxide generating free radicals and a radically polymerizable bifunctional or more functional acrylate compound or methacrylate compound are contained. When separated into layers, or when separated into a layer containing an organic peroxide that generates free radicals and a layer containing conductive particles, the pot life can be improved.

The film-like adhesive for circuit connection of the present invention comprises:
During the operation of the semiconductor chip, to prevent malfunction due to light from the external light source, black, brown, by adding carbon black, pigment, dye in the film adhesive
It may be a light-shielding film of blue or the like.

The film-like adhesive for circuit connection of the present invention comprises:
The present invention can be used for electrical and mechanical connection between an IC chip and a circuit board and electrical and mechanical connection between electric circuits. The film-like adhesive for circuit connection of the present invention is, for example, a semiconductor chip and a circuit board are adhered and fixed by a face-down method with the film-like adhesive for circuit connection of the present invention interposed therebetween, and both electrodes are electrically connected. Can be used when That is, a first circuit member having a first connection terminal, and a second circuit member having a second connection terminal, the first connection terminal and the second connection terminal are arranged facing each other, The film-like adhesive for circuit connection of the present invention is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and the first connection terminal and the second connection terminal arranged opposite to each other by heating and pressing. Can be electrically connected. Such circuit members include semiconductor chips, resistor chips,
Chip components such as capacitor chips, circuit boards such as printed boards and flexible printed boards, image display boards such as LCD panels, PDP panels and EL panels, tape carrier packages, and circuit parts such as COFs are used. These circuit members are usually provided with a large number of connection terminals (in some cases, a single connection terminal may be provided), and at least one set of the circuit members has at least a part of the connection terminals provided on the circuit members opposed to each other. Then, the film-like adhesive for circuit connection of the present invention is interposed between the opposed connection terminals, and heated and pressed to electrically connect the opposed connection terminals to form a circuit board. By heating and pressing at least one set of the circuit members, the connection terminals arranged opposite to each other can be electrically connected by direct contact or via conductive particles of an anisotropic conductive adhesive.

According to the method of connecting circuit terminals of the present invention, a film-like adhesive for circuit connection having curability by radical polymerization is applied to one electrode circuit using a metal whose surface is selected from the group consisting of gold, silver, tin and platinum. After forming a conductor or coating the surface with plating etc., align with the other circuit electrode and heat,
It can be connected under pressure.

In the method for connecting circuit terminals of the present invention, the surface of the circuit board having the circuit electrodes is cleaned to remove contaminants and oxide films on the surface, whereby the film-like adhesive for circuit connection of the present invention is removed. The connection reliability can be improved by increasing the adhesive strength to the circuit board. The method of cleaning the surface of the circuit board is not particularly limited as long as the influence of damage to circuit electrodes and wiring is small. Examples of cleaning include cleaning with pure water,
Washing or wiping with a solvent, plasma treatment, and the like can be given.

In the present invention, connection can be made in a shorter time than conventional radical-curable acrylate resin-based adhesives, and excellent adhesive strength can be exhibited even after a moisture resistance test, and storage stability, film formability, and handling can be improved. It is possible to provide a film-like adhesive for electric / electronic circuit connection with improved performance.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modified polyhydroxypolyether resin containing a fluorene skeleton and butadiene elastomer containing a carboxyl group used as a thermoplastic resin having a glass transition temperature of 50 ° C. or more and a melt viscosity at 150 ° C. of 10,000 Pa · s or less used in the present invention. A method for synthesizing a high molecular weight phenoxy resin is shown below.

<Synthesis of Polyhydroxy Polyether Resin> 4,4- (9-Fluorenylidene) -diphenol 45
g, 3,3 ′, 5,5′-tetramethylbiphenol diglycidyl ether 50 g, N-methylpyrrolidion 1000 m
, and 21 g of potassium carbonate was added thereto.
Stirred at C for 3 hours. After stirring, the mixture was dropped into a large amount of methanol, and the resulting precipitate was collected by filtration to obtain 75 g of a polyhydroxypolyether resin (b) having a fluorene skeleton in the molecule, which is the target substance. The result of measuring the molecular weight (GPC8020 manufactured by Tosoh Corporation, column: TPC manufactured by Tosoh Corporation)
SKgelG3000H _XL and TSKgelG4000H
_XL , flow rate 1.0 ml / min), M in terms of polystyrene
n = 12,500, Mw = 30,300, Mw / Mn =
2.42. The resin (b) was dissolved in THF (tetrahydrofuran), applied to a petri dish, and the solvent was diffused to prepare a cast film. The cast film was measured using a dynamic viscoelasticity measuring device (RSA-II manufactured by Rheometric Scientific) (heating rate 5 ° C./min, 1 Hz), and as a result of measuring the glass transition temperature by the peak of tan δ, The glass transition temperature was 95 ° C. The cast film was measured using a shear viscoelasticity measuring device (ARES manufactured by Rheometric Scientific) (heating rate 5 ° C./min, 1 Hz), and the viscosity at 150 ° C. was determined. As a result, 4800 Pa · s (48 , 000 poise).

<Synthesis of Carboxyl Group-Containing Butadiene Elastomer-Modified High Molecular Weight Phenoxy Resin> Tetrabromobisphenol A (FG-2000) was placed in a 2-liter four-necked flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube, and a mechanical stirrer. 333.83 g, trade name, manufactured by Teijin Chemicals Limited, bisphenol A type epoxy resin (YD-8125, molecular distilled product, epoxy equivalent 17)
2g / equivalent, trade name of Toto Kasei Co., Ltd.) 205.56
g and N, N-dimethylacetamide (1257 g) were added, and the mixture was stirred and mixed under a nitrogen atmosphere until the mixture became uniform. Next, 0.94 g of lithium hydroxide was added and reacted at 120 ° C. for 9 hours while gradually increasing the temperature. For tracking the reaction, the viscosity of the reaction solution was measured at regular intervals, and the reaction was continued until the viscosity did not increase. After completion of the reaction, the reaction solution was allowed to cool, and activated alumina (200 mesh) of about 4
20 g was added and left overnight. The activated alumina was filtered to obtain a solution of the phenoxy resin in N, N-dimethylacetamide. Next, 807.62 g of an N, N-dimethylacetamide solution of the obtained phenoxy resin, butadiene-acrylonitrile containing a terminal carboxyl group were placed in a 1-liter four-necked flask equipped with a nitrogen inlet tube, a thermometer, a cooling tube, and a mechanical stirrer. Copolymer (Hycar
CTBNX1009-SP, trade name, manufactured by Ube Industries, Ltd.) 50.88
g, and the mixture was sufficiently purged with nitrogen while stirring and mixing. Next, the mixture was stirred and mixed under a nitrogen atmosphere, and heated for 8.5 hours in a state where the solvent was refluxed while gradually raising the temperature, to obtain an N, N-dimethylacetamide solution of the target elastomer-modified high molecular weight phenoxy resin. . The resulting solution was a brown-brown transparent one and was measured using a cone-plate viscometer (EMD
The viscosity measured with a mold (manufactured by Tokimec Co., Ltd.) is about 0.3
Pa · s (300 cP). A part of the reaction solution was poured into a large amount of methanol to precipitate a solid, washed with methanol, and dried under reduced pressure to obtain an elastomer-modified high molecular weight phenoxy resin. The molecular weight of the obtained elastomer-modified high-molecular-weight phenoxy resin was determined using GPC802 manufactured by Tosoh Corporation.
0, column is TSKgelG3000 manufactured by Tosoh Corporation
H _XL and TSKgelG4000H _XL , flow rate 1.0 ml /
As a result, Mn = 1 in terms of polystyrene.
8,200, Mw = 38,400, Mw / Mn = 2.1
It was one. This resin (c) was dissolved in N, N-dimethylacetamide, applied to a petri dish, and the solvent was diffused to prepare a cast film. The cast film was measured using a dynamic viscoelasticity measuring device (RSA-II manufactured by Rheometric Scientific) (heating rate 5 ° C./min, 1 Hz), and as a result of measuring the glass transition temperature by the peak of tan δ, Glass transition temperature was 90 ° C. The cast film was measured using a shear viscoelasticity measuring device (ARES manufactured by Rheometric Scientific) (heating rate 5 ° C./min, 1 Hz), and the viscosity at 150 ° C. was determined. , 700 poise). Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. Table 1 shows materials used in Examples and Comparative Examples.

Example 1 As a thermoplastic resin having a glass transition temperature of 50 ° C. or more and a melt viscosity at 150 ° C. of 10,000 Pa · s or less, the fluorene skeleton-containing polyhydroxy polyether resin (B) synthesized above was toluene:
5 dissolved in a mixed solution of ethyl acetate = 1: 1 (weight ratio)
80% by weight of a 0% by weight solution and a 50% by weight solution of a carboxyl group-containing butadiene elastomer-modified high molecular weight phenoxy resin (C) synthesized above in a mixed solution of toluene: ethyl acetate = 1: 1 (weight ratio). 40 parts by weight, dimethylol tricyclodecane diacrylate (A) 40 parts by weight as a radically polymerizable bifunctional or higher acrylate compound, and room temperature (25 ° C.) as an organic peroxide
1,1-bis (t-hexylperoxy) which is liquid in
-3,3,5-trimethylcyclohexane (half-life decomposition temperature of 1 minute 147 ° C., half-life decomposition temperature of 100 hours 6
(9 ° C.) (D) 5 parts by weight, (3-methacryloxypropyl) trimethoxysilane (G) as a silane coupling agent having a radical polymerizable functional group was added to 2-butanone and dispersed by ultrasonic waves. A 50% by weight solution was stirred at 20 parts by weight to obtain a varnish solution for film coating. This solution was applied to a separator (silicone-treated polyethylene terephthalate film, thickness 80 μm) with a roll coater, and dried at 70 ° C. for 10 minutes to prepare a 20 μm thick film-like adhesive for circuit connection.

Example 2 10 parts by weight of Ni / Au plated polystyrene particles (average particle diameter 5 μm) (I) were mixed with the varnish solution for film coating of Example 1 to obtain a varnish solution for film coating. 20 μm in thickness in the same manner as in Example 1.
Was prepared.

Example 3 The fluorene skeleton-containing polyhydroxypolyether resin (B) was changed from 80 parts by weight to 120 parts by weight as the thermoplastic resin of Example 2, and the carboxyl group-containing butadiene elastomer-modified high molecular weight phenoxy resin (C) was used. ) Was prepared in the same manner as in Example 2 except that) was not added.

Example 4 In Example 2, the organic peroxide was replaced with 1,1-bis (t-t) which was liquid at room temperature (25 ° C.).
Hexylperoxy) -3,3,5-trimethylcyclohexane (D) 5 parts by weight at room temperature (25 ° C.) 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane (1 1 minute half-life decomposition temperature 158 ° C, 1
A half-life decomposition temperature of 00 hours (83 ° C.) (E) A 20 μm-thick film-like adhesive for circuit connection was produced in the same manner as in Example 2 except that the weight was changed to 5 parts by weight.

Example 5 The organic peroxide in Example 3 was replaced with 1,1-bis (t-t) which was liquid at room temperature (25 ° C.).
Hexylperoxy) -3,3,5-trimethylcyclohexane (D) from 5 parts by weight at room temperature (25 ° C.) 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane (E) A) A film-like adhesive for circuit connection having a thickness of 20 μm was prepared in the same manner as in Example 3 except that the amount was changed to 5 parts by weight.

Comparative Example 1 The procedure of Example 4 was repeated except that the silane coupling agent (G) was not used.
A film-like adhesive for circuit connection having a thickness of 20 μm was prepared in the same manner as in the above.

Comparative Example 2 The procedure of Example 4 was repeated except that the silane coupling agent (F) was changed to a silane coupling agent (H) having no radically polymerizable functional group. Thus, a film-like adhesive for circuit connection having a thickness of 20 μm was prepared.

(Comparative Example 3) In Example 4, the organic peroxide (E) was converted to 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3 (half-life decomposition for 1 minute). Temperature 194 ° C, 100 hour half-life decomposition temperature 109 ° C)
(F) except that the thickness was 2
A film-shaped adhesive for circuit connection of 0 μm was produced.

(Comparative Example 4) In Example 4, a radically polymerizable bifunctional or higher acrylate compound was replaced with a monofunctional acrylate compound, imide acrylate (A ').
Except that the thickness was changed to 20 μm in the same manner as in Example 4.
Was prepared.

The materials used in Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 1, and the composition is shown in Table 2.

[0043]

[Table 1]

[0044]

[Table 2]

The circuit connection and measurement method used in the present invention are described below. <Circuit connection> Gold plated bumps (50 μm × 50 μm,
IC chip (1.5mm × 17mm × 0.55mm) with bump height 15μm, space 50μm) and 0.7m
A substrate having electrodes formed of ITO on a glass having a thickness of m is interposed with the above-mentioned film-forming adhesive for circuit connection,
C., 100 MPa (in terms of bump area), heating and pressurizing for 3 seconds for connection, thereby producing a connection reliability measurement sample. At this time, after a film-like adhesive for circuit connection is pasted on the glass substrate in advance, a temporary connection is performed by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then a PE as a separator is formed.
The T film was peeled off and connected to an IC chip under the above conditions to prepare a connection reliability measurement sample.

<Connection Reliability Measurement Method> The connection resistance of the connection reliability measurement sample immediately after connection and the humidity resistance test (85 ° C.,
(85% RH) after 500 hours, and the connection resistance was measured by a four-terminal method. Those whose connection resistance could not be measured were regarded as OPEN failures. <Appearance inspection after moisture resistance> The connection surface after the moisture resistance test of the sample for connection reliability measurement described above was observed with a metal microscope. The sample without peeling was rated as “○”, and the sample with peeling was rated as “x”. <Adhesive strength measurement method> Gold plated bump (50 μm × 50
μm, bump height 15μm, space 10μm)
A C chip (1.0 mm × 10 mm × 0.55 mm) and a glass substrate having a thickness of 0.7 mm are interposed with the above-mentioned adhesive film for circuit connection at 200 ° C. and 100 MPa (in terms of bump area) for 3 seconds. After connecting, bond tester (D
The shearing adhesive strength was measured immediately after bonding and after 168 hours of a moisture resistance test (85 ° C., 85% RH). <Measurement of exothermic onset temperature> Differential scanning calorimeter (DSC, TA Instruments Japan
(2000 thermal analysis system), the exothermic onset temperature of the film-like adhesive for circuit connection was measured at a rate of temperature increase of 10 ° C./min.

<Storage stability test> After leaving the film-like adhesive for circuit connection in a constant temperature bath at 40 ° C for 5 days, the adhesive strength and connection reliability were measured by the above-mentioned methods.

Table 2 shows the results of these measurements. Examples 1 and 2 differ in the presence or absence of the conductive particles, but there is no difference in the connection strength, the connection resistance, and the like in Table 2, but a stable connection can be obtained by blending the conductive particles. Comparative Example 1 is a case where the silane coupling agent having a radical polymerizable functional group of Example 4 is not blended,
As compared with Example 4, the adhesive strength was significantly reduced, and the connection resistance was increased. Also, in Comparative Example 2 in which a silane coupling agent having an epoxy group having no radically polymerizable functional group was added as the silane coupling agent, the adhesive strength was significantly reduced, and the connection resistance was increased. Comparative Example 3 is Example 4
In this case, the heat generation starting temperature was higher than 150 ° C. by changing the organic peroxide, and the adhesive strength was significantly reduced and the connection resistance was increased. Comparative Example 4 is a case where a monofunctional acrylate compound was used in place of the radical polymerizable bifunctional or higher acrylate compound of Example 4, but the adhesive strength was significantly reduced and the connection resistance was increased. did. On the other hand, in Examples 1 to 5 of the present invention, 200
The bonding strength, the connection resistance, and the appearance after moisture resistance were good by short-time connection at 3 ° C. for 3 seconds. In particular, (1) a radically polymerizable bifunctional or higher acrylate compound, (2) a glass transition temperature of 50 ° C. or higher and a melt viscosity at 150 ° C. of 10,000 P
a.s or less thermoplastic resin, (3) a powdery organic peroxide at room temperature (25 ° C.), (4) a silane coupling agent having a radical polymerizable functional group, and an exothermic initiation temperature of 100 ℃ or more, 150 ℃ or less, adhesive strength,
The connection resistance and the appearance after moisture resistance were improved.

[0049]

According to the present invention, connection can be made in a shorter time than conventional radical-cured acrylate resin-based adhesives, excellent adhesive strength can be obtained even after a moisture resistance test, storage stability and film formation can be achieved. Electricity with excellent performance and handling
It becomes possible to provide a film-like adhesive for electronic circuit connection.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4J004 AA01 AA10 AA12 AA13 AA15 AA16 BA02 FA05 4J040 DD051 DD052 EB021 EB022 EC001 EC002 EC311 EC312 ED001 ED002 EE061 EE062 EG001 EG001 EG002 FA141 FA142 FA161 FA162 FA171 FA 172 FA 321 FA 321 JA09 JB02 KA30 KA32 LA01 LA02 LA06 LA09 LA11 MA02 MA05 MB03 NA20 NA21 PA30 5F044 KK06 LL07 LL11 LL15

Claims (6)

[Claims] 1. A film-like adhesive for circuit connection which is interposed between opposed circuit electrodes and heats and presses the opposed circuit electrodes to electrically connect the electrodes in the pressure direction.
(1) a radically polymerizable bifunctional or higher acrylate or methacrylate compound; (2) a glass transition temperature of 50 ° C. or higher and a melt viscosity at 150 ° C. of 10,000 Pa
-S or less thermoplastic resin, (3) organic peroxide, (4)
A silane coupling agent having a radical polymerizable functional group is an essential component, and an exothermic onset temperature of 100 ° C. or more, 150
A film-like adhesive for circuit connection having a temperature of not more than ° C. 2. A method according to claim 1, wherein (1) a radically polymerizable bifunctional or more functional acrylate compound or methacrylate compound
100 parts by weight, (2) the glass transition temperature is 50 ° C. or more,
100 parts by weight of a thermoplastic resin having a melt viscosity at 150 ° C. of 10,000 Pa · s or less, (3) 1 to 20 parts by weight of an organic peroxide with respect to 100 parts by weight of a radically polymerizable bifunctional or more acrylate compound or methacrylate compound,
(4) 5 parts by weight of a silane coupling agent having a radical polymerizable functional group per 100 parts by weight of the total weight of (1) to (3).
The film-like adhesive for circuit connection according to claim 1, which is blended in an amount of 15 to 15 parts by weight. 3. The organic peroxide is a powder at room temperature (25 ° C.), has a one-minute half-life decomposition temperature of 180 ° C. or less, and has a 100-hour half-life decomposition temperature of 40 ° C. or more. The film-like adhesive for circuit connection according to claim 1 or 2, wherein 4. The film-like adhesive for circuit connection according to claim 1, further comprising conductive particles. 5. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged such that the first connection terminal and the second connection terminal face each other. The film-like adhesive for circuit connection according to any one of claims 1 to 4 is interposed between the first connection terminal and the second connection terminal arranged opposite to each other. A connection structure of circuit terminals in which the first connection terminal and the second connection terminal are electrically connected. 6. A first circuit member having a first connection terminal and a second circuit member having a second connection terminal are arranged with the first connection terminal and the second connection terminal facing each other. The film-like adhesive for circuit connection according to any one of claims 1 to 4 is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and heated and pressurized to form the opposed connection. A method of connecting circuit terminals for electrically connecting the first and second connection terminals arranged.