JPH10273626A - Circuit connecting material and production of circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject material excellent in low-temperature curing property, having a pot life, inserted between mutually opposed circuit electrodes, pressurizing mutually opposed circuit electrodes to electrically connect between electrodes in pressurizing direction by including a curing agent, a radically polymerizable substance and electroconductive particles as essential components. SOLUTION: This circuit connecting material consists essentially of (A) a curing agent generating a free radical by heating, (B) a radical polymerizable substance and (C) electroconductive particles whose surface layer is composed of at least one kind of metal selected from gold, silver and a metal of platinum group. Furthermore, a temperature in 10 hr half life of the component A is >=40 deg.C and a temperature in 1 min half life of the component A is <=180 deg.C, and benzoyl peroxide, etc., is used as the component A and methyl acrylate, etc., is used as the component B and thickness of metal of surface layer is preferably 300Å.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a circuit connecting material and a circuit board using an adhesive composition and conductive particles.

[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 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, a specific performance is generally obtained by various combinations of the epoxy resin and the curing agent and the modifying agent. (For example, JP-A-62-141083).

[0003]

However, although the film adhesive disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Sho 62-141083 is excellent in workability, it can be heated at about 140 to 180 ° C. with a connection time of about 20 seconds. 180-2 for 10 seconds
Heating of about 10 ° C. was required. The reason for this is that a catalyst-type curing agent that is inactive at room temperature is used for the purpose of obtaining good stability by achieving both short-time curing (rapid curing) and storage stability (preservability). This is because a sufficient reaction cannot be obtained during curing. In recent years, in the field of precision electronic equipment, the density of circuits has been increasing, and the electrode width and electrode interval have become extremely narrow. For this reason, under the conventional connection condition of the circuit connection material using the epoxy resin system, there has been a problem that the wiring is dropped, peeled off or displaced. In addition, it is required to shorten the connection time to 10 seconds or less in order to improve production efficiency, and low-temperature rapid curing is indispensable. An object of the present invention is to provide an electric / electrical device that has excellent low-temperature and quick-curing properties and has a long working life than conventional epoxy resin systems.
An object of the present invention is to provide an electronic circuit connection material.

[0004]

The circuit connecting material of the present invention is a connecting material which is interposed between opposing circuit electrodes and presses the opposing circuit electrodes to electrically connect the electrodes in the pressing direction. In addition, the following components (1) to (3) are essential. (1) Curing agent that generates free radicals upon heating (2) Radical polymerizable substance (3) Conductive particles whose surface layer is composed of at least one selected from gold, silver and platinum group metals Heating free radicals Half-life of curing agent that generates
The temperature of the time is 40 ° C or more and the temperature of the half-life of 1 minute is 18
A curing agent having a temperature of 0 ° C. or lower is preferable, and a metal having a thickness of 300 Å or more in the conductive particle surface layer is preferable. The method for manufacturing a circuit board according to the present invention includes a first circuit member having a first connection terminal, a second circuit member having a second connection terminal, and a first connection terminal and a second connection terminal. Are disposed facing each other, the circuit connection material of the present invention is interposed between the first connection terminal and the second connection terminal disposed opposite to each other, and the first connection terminal and the second connection terminal disposed opposite each other by heating and pressing. The two connection terminals are electrically connected.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The curing agent used in the present invention, which generates free radicals by heating, is one which decomposes upon heating a peroxide compound, an azo compound or the like to generate free radicals. The temperature is appropriately selected depending on the temperature, the connection time, the storage stability and the like. However, from the viewpoint of high reactivity and storage stability, the temperature at a half-life of 10 hours is 40 ° C. or more and the half-life is 1
An organic peroxide having a temperature of 180 ° C. or less for a minute is preferable, and an organic peroxide having a temperature of 60 ° C. or more for a half-life of 10 hours and a temperature of 170 ° C. or less for a half-life of 1 minute is more preferable. In this case, the compounding amount is about 0.05 to 10% by weight and 0.1
-5% by weight is more preferred. Specifically, it can be selected from diacyl peroxide, peroxydicarbonate, peroxyester, peroxyketal, dialkyl peroxide, hydroperoxide and the like.

The diacyl peroxides include 2,2
4-dichlorobenzoyl peroxide, 3,5,5
-Trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide,
Benzoyl peroxytoluene, benzoyl peroxide and the like.

The peroxydicarbonates include di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, bis (4-tert-butylcyclohexyl) peroxydicarbonate, and di-2-ethoxymethoxyperoxydicarbonate. Carbonate, di (2-ethylhexylperoxy) dicarbonate, dimethoxybutylperoxydicarbonate, di (3-methyl-3
-Methoxybutylperoxy) dicarbonate.

[0008] As peroxyesters, 1,1,
3,3, -tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxynodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxypivalate, 1, 1,
3,3, -tetramethylbutylperoxy 2-ethylhexanonate, 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy 2- Ethyl hexanonate, t-hexyl peroxy 2-ethyl hexanonate, t-butyl peroxy 2-ethyl hexanonate, t-butyl peroxyisobutyrate, 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-toluene oil) Peroxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butyl Peroxy 2-ethylhexyl monocarbonate, t chromatography hexyl peroxybenzoate,
t-butyl peroxyacetate and the like.

The peroxyketals include 1,1, -bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, and 1,1-bis (t -Butylperoxy) -3,3,5-trimethylcyclohexane,
1,1,1- (t-butylperoxy) cyclododecane,
2,2-bis (t-butylperoxy) decane and the like.

[0010] Among the dialkyl peroxides, α,
α'bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5, di (t-butylperoxy) hexane, t-butylcumyl peroxide and the like.

Hydroperoxides include diisopropylbenzene hydroperoxide, cumene hydroperoxide and the like. 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. 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.

The radically polymerizable substance used in the present invention is a substance having a functional group capable of being polymerized by a radical, such as acrylate and methacrylate. The radical polymerizable substance can be used in any state of a monomer and an oligomer, and the monomer and the oligomer can be used in combination. Specific examples of acrylate (methacrylate) include methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, and 2-hydroxy 1.3. Diacryloxypropane, 2,2-bis [4- (acryloxymethoxy)
Phenyl] propane, 2,2-bis [4- (acryloxypolyethoxy) phenyl] propane, dicyclopentenyl acrylate, tricyclodecanyl acrylate,
Tris (acryloyloxyethyl) isocyanurate and the like. These can be used alone or in combination. If necessary, a polymerization inhibitor such as hydroquinone or methyl ether hydroquinone may be used as appropriate. 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.

The above radical polymerizable substances include polystyrene, polyethylene, polyvinyl butyral, polyvinyl formal, polyimide, polyamide, polyester, polyvinyl chloride, polyphenylene oxide, urea resin, melamine resin, phenol resin, xylene resin,
Polymers such as epoxy resins, polyisocyanate resins, and phenoxy resins are preferred because they have good handleability and are excellent in stress relaxation during curing, and those having a functional group such as a hydroxyl group are more preferred because they improve adhesion. It is more preferable that each polymer is modified with a radical polymerizable functional group. The molecular weight of these polymers is preferably 10,000 or more, but when the molecular weight is more than 1,000,000, the mixing property deteriorates.

Further, it may contain a filler, a softening agent, an accelerator, an antioxidant, a coloring agent, a flame retardant, a thixotropic agent, a coupling agent, a phenol resin, a melamine resin, and an isocyanate. It is preferable to include a filler, because an improvement in connection reliability and the like can be obtained. Can be used if the maximum diameter of the filler is less than the particle diameter of the conductive particles,
A range of 5 to 60% by volume is preferred. At 60% by volume or more, the effect of improving reliability is saturated. As the coupling agent, a vinyl group, an acryl group, an amino group, an epoxy group, and an isocyanate group-containing material are preferable from the viewpoint of improving the adhesiveness.

The conductive particles used in the present invention include:
There are metal particles such as Au, Ag, Ni, Cu, and solder, carbon, and the like.
Instead of transition metals such as i and Cu, Au, Ag, and platinum group noble metals are preferable, and Au is more preferable. Also, Ni
The surface of a transition metal such as may be coated with a noble metal such as Au. In addition, non-conductive glass, ceramic,
The conductive layer formed of a plastic or the like by coating or the like and the outermost layer made of a noble metal is preferable because it has a deformability due to heating and pressurizing, so that a contact area with an electrode increases at the time of connection and reliability is improved. 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, free radicals are generated due to oxidation-reduction action caused by a defect of the noble metal layer or a defect of the noble metal layer generated when mixing and dispersing the conductive particles. In order to cause deterioration in the properties, the thickness is preferably 300 Å or more. The conductive particles are properly used in a range of 0.1 to 30 parts (volume) with respect to 100 parts (volume) of the adhesive resin component depending on the use. In order to prevent a short circuit or the like in an adjacent circuit due to excessive conductive particles, the content is more preferably 0.1 to 10 parts (volume).

Further, when the circuit connecting material of the present configuration is divided into two or more layers and separated into a layer containing a hardener generating free radicals and a layer containing conductive particles, the conventional effect of achieving higher definition can be obtained. In addition, storage stability can be improved.

The circuit connecting material of the present invention is also useful as a film adhesive for bonding an IC chip to a substrate and for bonding electric circuits to each other. The connection of the electrodes using the circuit connection material obtained in the present invention will be described. In this method, a circuit connecting material is formed between opposing electrodes on a substrate, and the electrodes are connected by heating and pressing to obtain contact between the electrodes and adhesion between the substrates. As a substrate on which electrodes are formed, inorganic materials such as semiconductors, glass, and ceramics, organic materials such as polyimide and polycarbonate, and combinations of these composite materials such as glass / epoxy can be used.

The circuit connecting material of the present invention can also be used, for example, when a semiconductor chip is adhered and fixed to a substrate with an adhesive film by a face-down method and both electrodes are electrically connected. 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 connection material (film adhesive) of the present invention is interposed between the first connection terminal and the second connection terminal that are arranged to face each other, and heated and pressurized, and the first connection terminal and the second connection that are arranged to face each other. The circuit board can be manufactured by electrically connecting the terminals.

Such circuit members include chip parts such as a semiconductor chip, a resistor chip, and a capacitor chip.
A board such as a printed board is 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 is arranged so that at least a part of the connection terminals provided on the circuit members are opposed to each other. Then, an adhesive 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 pressurizing at least one set of circuit members, the connection terminals arranged to face each other can be electrically connected by direct contact or via conductive particles of an anisotropic conductive adhesive.

[0020]

According to the present invention, it is possible to provide an electric / electronic circuit connecting material which has excellent low-temperature and quick-curing properties and has a usable life as compared with the conventional epoxy resin system.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. In addition, each compounding ratio is put together in the table of FIG. Example 1 50 g of a phenoxy resin (manufactured by Union Carbide Co., Ltd., trade name: PKHC, average molecular weight: 45,000) was mixed in a weight ratio of toluene (boiling point: 110.6 ° C, SP value: 8.90) /
Ethyl acetate (boiling point 77.1 ° C., SP value 9.10) = 50
/ 50 to obtain a solution having a solid content of 40%. As a radical polymerizable substance, trihydroxyethyl glycol dimethacrylate (trade name: 80MFA, manufactured by Kyoeisha Yushi Co., Ltd.) was used. Benzoyl peroxide was used as a free radical generator. A nickel layer having a thickness of 0.2 μm was provided on the surface of the particles having polystyrene as a core, and a gold layer having a thickness of 0.04 μm was provided outside the nickel layer to produce conductive particles having an average particle diameter of 10 μm. A phenoxy resin 50 g, trihydroxyethyl glycol dimethacrylate resin 50 g, and benzoyl peroxide 5 g were blended in a solid weight ratio, and 3 vol% of conductive particles were further blended and dispersed therein, and a coating apparatus was applied to a fluororesin film having a thickness of 80 μm. And a hot-air drying at 70 ° C. for 10 minutes to obtain a circuit connection material having an adhesive layer thickness of 35 μm. The obtained film adhesive showed sufficient flexibility at room temperature, and showed almost no change in the properties of the film even after being left at 40 ° C. for 10 hours, showing good storage stability.

Examples 2 and 3 The solid weight ratio of phenoxy resin / trihydroxyethyl glycol dimethacrylate was changed to 50 g / 50 g.
A circuit connecting material was obtained in the same manner as in Example 1 except that the amount was 30 g / 70 g (Example 2) and 70 g / 30 g (Example 3).

Example 4 Example 4 was repeated except that a 40% by weight solution of benzoyl peroxytoluene in toluene (Niper BMT-T40, manufactured by NOF Corporation) was used instead of trihydroxyethyl glycol dimethacrylate as a curing agent. In the same manner as in Example 1, a circuit connecting material was obtained.

Example 5 Benzoyl peroxytoluene in a 40% by weight toluene solution (Nipper BMT-T4, manufactured by NOF Corporation)
A circuit connecting material was obtained in the same manner as in Example 1 except that the blending amount of 0) was 2 g.

Example 6 The procedure of Example 6 was repeated, except that a 40% by weight benzoyl peroxytoluene solution (trade name, Niiper BMT-T40, manufactured by NOF Corporation) was used instead of trihydroxyethyl glycol dimethacrylate as the curing agent. In the same manner as in Example 1, a circuit connecting material was obtained.

Example 7 A 50% by weight DOP solution of t-hexylperoxy 2-ethylhexanonate (trade name Percure HO, manufactured by NOF Corporation) was used in place of trihydroxyethyl glycol dimethacrylate as a curing agent. Otherwise, a circuit connecting material was obtained in the same manner as in Example 1.

Example 8 Phenoxy resin (PKHC) having an average molecular weight of 45,000
5 g of a monoisocyanate having an acrylic group at the terminal was reacted with 100 g by a general method to prepare a phenoxy resin modified with an acrylic group. A circuit connecting material was obtained in the same manner as in Example 1 except that this phenoxy resin was used.

Example 9 Ni particles having an average particle diameter of 2 μm coated with Au (0.08 μm coating thickness) were used as conductive particles.
A circuit connecting material was obtained in the same manner as in Example 1 except that the amount was 5 parts (volume).

Example 10 A circuit connecting material was obtained in the same manner as in Example 1, except that the particle size of the conductive particles was changed to 5 μm.

Example 11 Circuit connection was performed in the same manner as in Example 1 except that 30 g of trihydroxyethyl glycol dimethacrylate (trade name: 80MFA, manufactured by Kyoeisha Yushi Co., Ltd.) and 20 g of dicyclopentenyl acrylate were used as radical polymerizable substances. The material was obtained.

Example 12 A circuit was prepared in the same manner as in Example 1 except that 30 g of trihydroxyethyl glycol dimethacrylate (trade name: 80MFA, manufactured by Kyoeisha Yushi Co., Ltd.) and 20 g of tricyclodecanyl acrylate were used as radically polymerizable substances. The connection material was obtained.

Example 13 The procedure of Example 1 was repeated except that 40 g of trihydroxyethyl glycol dimethacrylate (trade name: 80MFA, manufactured by Kyoeisha Yushi Co., Ltd.) and 10 g of tris (acryloyloxyethyl) isocyanurate were used as radical polymerizable substances. Similarly, a circuit connecting material was obtained.

Example 14 Except that 2.2-bis {4- (acryloxydiethoxy) phenyl} propane (trade name: A-BPE-4, manufactured by Shin-Nakamura Chemical Co., Ltd.) was used as the radical polymerizable substance. A circuit connecting material was obtained in the same manner as in Example 1.

Example 15 Except that the phenoxy resin was polyvinyl butyral resin (trade name: PVB3000K, manufactured by Denki Kagaku Kogyo KK)
A circuit connecting material was obtained in the same manner as in Example 1.

Example 16 Ni particles having an average particle size of 2 μm coated with conductive particles and coated with Pd (coating thickness 0.04 μm) were used.
A circuit connecting material was obtained in the same manner as in Example 1 except that the content was 5% by volume.

Comparative Example 1 Except that di-t-butyl peroxide was used as a curing agent,
A circuit connecting material was obtained in the same manner as in Example 1.

Comparative Example 2 A circuit connecting material was obtained in the same manner as in Example 1, except that isobutyl peroxide was used as the curing agent.

Comparative Example 3 A circuit connecting material was obtained in the same manner as in Example 1, except that the conductive particles were Ni particles having an average particle size of 2 μm.

Comparative Example 4 A circuit connecting material was obtained in the same manner as in Example 10, except that the thickness of the gold plating layer of the conductive particles was 0.02 μm.

Circuit Connection Using the above-described circuit connection material, a flexible circuit board (FPC) having 500 copper circuits having a line width of 50 μm, a pitch of 100 μm, and a thickness of 18 μm is connected to each other at 160 ° C. and 3MP.
a and heated and pressed for 10 seconds to connect over a width of 2 mm.
At this time, after the adhesive surface of the circuit connecting material is pasted on one of the FPCs in advance, the connection is made temporarily by heating and pressing at 70 ° C. and 0.5 MPa for 5 seconds, and then the fluororesin film is peeled off and the other side is removed. FPC.

Measurement of connection resistance After connecting the circuits, the multimeter was used to hold the resistance between the adjacent circuits of the FPC including the above-mentioned connection parts in the initial stage and in a high-temperature and high-humidity bath at 85 ° C. and 85% RH for 500 hours. Was measured. The resistance value was represented by an average (x + 3σ) of 150 points of resistance between adjacent circuits. The circuit connection material obtained in Example 1 showed good connection reliability. In addition, the initial connection resistance was low, and the resistance after the high-temperature and high-humidity test rose slightly, indicating high durability. In addition, the circuit connection materials of Examples 2 to 16 also obtained good connection reliability, and in any case, had good storage stability for 10 days or more at room temperature. On the other hand, in Comparative Example 1, the reactivity of the curing agent used was low, and the storage stability was 1 at room temperature.
Although it was as long as 0 days or more, the adhesion was poor due to insufficient curing reaction, and the initial connection resistance was high. In Comparative Example 2, the reactivity of the curing agent used was very high, and a good connection was obtained in the initial stage, but the storage stability was as short as one day. Furthermore, in Comparative Example 3, since the Ni particles were a transition metal, a good connection was initially obtained due to the oxidation-reduction action, but the storage stability was as short as one day. Further, in Comparative Example 4, the storage stability was shortened similarly to Comparative Example 3 because the gold plating layer was thin.

Measurement of Adhesive Strength After connection of the circuit, 90 ° peeling, peeling speed 50 mm / min
Was used to measure the adhesive strength. In Comparative Examples 1 to 4, 200 gf /
cm, but in Examples 1 to 16, the adhesive strength is low.
Good adhesive strength of about 0 gf / cm was obtained.

[0043]

As described above in detail, according to the present invention, it is possible to provide a circuit connecting material for electric / electronic devices which is excellent in low-temperature and quick-curing properties and has a long working life as compared with the conventional epoxy resin system. .

[Brief description of the drawings]

FIG. 1 is a table showing the measurement results of the adhesive strength and the connection resistance of a connection portion in Examples and Comparative Examples.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 201/00 C09J 201/00 H01B 1/20 H01B 1/20 D H01L 21/60 311 H01L 21/60 311S H05K 3/38 H05K 3/38 E

Claims (4)

[Claims] 1. A connecting material interposed between opposed circuit electrodes and pressurizing the opposed circuit electrodes to electrically connect the electrodes in the pressing direction. Circuit connection material that requires components. (1) Curing agent that generates free radicals upon heating (2) Radical polymerizable substance (3) Conductive particles whose surface layer is composed of at least one selected from gold, silver and platinum group metals 2. The curing agent which generates free radicals by heating has a half-life of 10 hours at a temperature of 40 ° C. or more and a half-life of 1 hour.
The circuit connecting material according to claim 1, wherein the temperature of the minute is 180 ° C or less. 3. The circuit connecting material according to claim 1, wherein the thickness of the metal of the surface layer is 300 Å or more. 4. 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. Then, the circuit connection material according to any one of claims 1 to 3 is interposed between the first connection terminal and the second connection terminal arranged opposite to each other, and the first connection terminal arranged opposite to each other by heating and pressing. A method of manufacturing a circuit board for electrically connecting a second connection terminal.