JP2000192000A - Electrically conductive adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electroconductive adhesive that has a sufficient adhesion strength and an electroconductivity with reduced fluctuation in its environmental properties by using a copper-including metal filler, an epoxy compound, a novolak type phenol resin, a low-molecular-weight phenol and a curing agent. SOLUTION: The objective electroconductive adhesive is prepared by mixing 10-80 wt.% of an epoxy compound, for example, a bisphenol-A type epoxy resin, 2-40 wt.% of a novolak type phenol resin, 5-50 wt.% of a low-molecular- weight polyphenol, for example, hydroquinone, in addition, a curing agent, for example, a microcapsule type epoxy curing agent to prepare an organic binder, then admixing a metal filler containing 50-100% of copper to the resultant organic binder in an amount of 40-95 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive adhesive used for assembling ICs, LSIs, other semiconductor elements, and various electric and electronic parts, or for bonding to a substrate.

[0002]

2. Description of the Related Art Conventionally, Sn-Pb eutectic solder (hereinafter referred to as "solder") has been used for assembling ICs, LSIs, other semiconductor devices, and various electric and electronic parts, or bonding them to a substrate because of their excellent conductivity and high reliability. Has been widely used. On the other hand, semiconductor elements and electric and electronic parts have been miniaturized and improved in function with recent miniaturization, and a large number of fine-pitch connection terminals in which the width and interval of the connection terminals are narrowed have been required. However, the solder has a risk of causing a bridging phenomenon at the time of soldering when the fine pitch of the connection terminal advances, and there is a limit in responding to the fine pitch. In addition, since the solder has a high reflow temperature, there are restrictions on members that can be joined, and the fact that solder contains lead has been a problem from the viewpoint of environmental protection.

[0003] In recent years, conductive adhesives have attracted attention as an adhesive material replacing solder. At present, it is required that the conductive adhesive has sufficient shear strength and conductivity, and that these characteristics have little fluctuation in an environmental test. Specifically, although it differs depending on the member to which the conductive adhesive is applied, a 2 mm square tip has a shear strength of 5 kgf or more, a connection resistance of 100 mΩ or less, and a variation rate of about 30% or less in a heat cycle test. is necessary. As the conductive adhesive, one obtained by mixing a thermosetting resin such as an epoxy resin with a silver filler is usually used. However, conductive adhesives using silver are expensive,
There is a limitation on the use because migration is likely to occur, and there is a demand for a less expensive and stable conductive adhesive using a copper-based powder that does not cause migration.

[0004] However, the copper-based conductive adhesive has a problem that the copper powder is oxidized during storage or at the time of curing, so that sufficient conductivity cannot be maintained. Although various measures have been taken to prevent oxidation, such as the addition of various additives or the use of a resole resin as a binder, the problem of weak strength or poor stability has not been solved. In an example using a resole resin, Japanese Patent Publication No. 7-1099
No. 30 is disclosed, but can be used only for paint applications because of its low strength. Also, JP-A-8-3023
No. 12 discloses an adhesive using a resole resin, but also in this case, sufficient strength has not been obtained. That is, at present, a copper-based conductive adhesive having sufficient strength and conductivity and excellent in long-term stability and thermal stability has not been developed.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copper-based conductive adhesive having sufficient strength and conductivity, and having a small variation in characteristics due to the surrounding environment.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a metal filler containing copper as an electrically conductive adhesive, an epoxy compound, and a novolak-type phenol resin. It has sufficient strength and electrical conductivity by using the essential components of a polyresin, a low molecular polyphenol compound, and a curing agent, and has small fluctuations in characteristics due to environmental tests and high reliability. This has led to the present invention.

That is, the present invention provides: A conductive material comprising a metal filler containing at least 50% by weight or more and 100% by weight or less of copper, an epoxy compound, a novolak type phenol resin, a low molecular weight polyvalent phenol, and a curing agent. Adhesive. 2. 2. The conductive adhesive according to 1, wherein the low-molecular polyvalent phenol is hydroquinone.

Hereinafter, the present invention will be described in detail. In the present invention, the organic binder means a component obtained by removing a metal filler from a conductive adhesive. The metal filler used in the present invention has a copper content of 50% by weight or more and 100% by weight or less. If the copper content is less than 50% by weight, migration due to metals other than copper is likely to occur. In addition, the conductivity is significantly impaired depending on the type of metal used other than copper. On the other hand, the content of copper is 50% by weight.
If it is above, it may be 100% by weight. This is because oxidation of copper is suppressed by the organic binder. Regarding the shape of the metal filler, spherical, flake-like, dendritic, and scale-like fillers can be used alone or in a mixture of two or more. Flake-like and dendritic shapes are more preferable for increasing the adhesive strength. The metal filler can be used by mixing a coarse powder and a fine powder. A commercially available metal filler having a copper content of 100% by weight can be used as it is, for example, FCC-SP manufactured by Fukuda Metal Foil Industry Co., Ltd.
-99.

As a method of synthesizing the metal filler of the present invention, a known method can be used. For example, there are a gas atomization method, a water atomization method, a centrifugal atomization method, a roll atomization method, a ball mill method, a jet method, a cold stream method, a reduction method, an electrolytic method, a carbonyl method, a vacuum evaporation method, a gas evaporation method, and the like. It is also possible to form a multilayer structure by a method using various coats and plating.
Among them, nitrogen, argon, hydrogen, synthesis by an inert gas atomization method using an inert gas such as helium, a gradient alloy structure based on the melting point difference of the metal can be formed at the time of cooling, there is no metal peeling compared with the plating powder, and This is a synthesis method with excellent migration resistance and oxidation resistance. JP-A-4-268
No. 381 discloses a method for producing a metal filler using silver and copper by an inert gas atomization method using an argon gas.

The mixing ratio of the metal filler to the organic binder can be selected in an appropriate range according to the use of the conductive adhesive. The compounding ratio is preferably from 40% by weight to 95% by weight. If it is less than 40% by weight, it is difficult to obtain sufficient conductivity. If it exceeds 95% by weight, the viscosity increases and the workability deteriorates. More preferably 50% by weight to 9%
5% by weight.

The epoxy compound in the present invention is a general term for compounds having an oxirane ring, and usually an epoxy resin and a low-molecular epoxy compound are used alone or as a mixture. Examples of such epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, (cresol) novolak type epoxy resin, halogenated bisphenol type epoxy resin, Resorcinol type epoxy resin, tetrahydroxyphenylethane type epoxy resin, polyalcohol polyglycol type epoxy resin, glycerin triether type epoxy resin, polyolefin type epoxy resin, epoxidized soybean oil, cyclopentadiene dioxide, vinylcyclohexene dioxide, etc. Is mentioned. A known rubber-modified epoxy resin can also be used. These may be used alone or as a mixture of two or more. Bisphenol A is required to provide sufficient adhesive strength.
Epoxy resins and naphthalene epoxy resins are preferred. In particular, bisphenol A type epoxy resin is preferred.

The low molecular weight epoxy compound is a compound which is usually used as a diluent for an epoxy resin, such as phenoxyalkyl monoglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Hexanediol-diglycidyl ether, neopentyl glycol-diglycidyl ether, glycerin diglycidyl ether, N, N-diglycidylaniline, N, N-diglycidyl toluidine, trimethylolpropane triglycidyl ether ,
Examples include glycerin triglycidyl ether and various liquid polysiloxane diglycidyl ethers. These may be used alone or as a mixture of two or more. By using such a low-molecular-weight epoxy compound instead of a low-boiling organic solvent as a diluent, it is possible to obtain a stable cured product without generation of voids during curing. There is also an advantage that the curing time can be reduced.

The low molecular weight epoxy compound 2 of the present invention
The viscosity at 5 ° C. is preferably from 1 cP to 200 cP, more preferably from 1 cP to 100 cP. A liquid epoxy compound having a viscosity at 25 ° C. of 200 cP or less is preferable because a conductive adhesive having an appropriate viscosity can be obtained by adding a small amount. Preferred examples of such compounds include neopentyl glycol diglycidyl ether and trimethylolpropane triglycidyl ether. Organic binder in the present invention
The weight ratio of the epoxy compound in the composition is 10% to 80% by weight.
Is preferred. If it is less than 10% by weight, the viscosity becomes high, the workability is deteriorated, and it is difficult to obtain a sufficient strength. If it exceeds 80% by weight, sufficient conductivity is not exhibited.
More preferably, the content is 20% by weight to 70% by weight. When the epoxy resin is used alone, 30% by weight to 70% by weight is used.
% By weight is preferred.

The novolak phenol resin of the present invention is synthesized from phenol and formalin. Since the resole type phenol resin generates a volatile component at the time of curing, voids are generated in the adhesive and the reliability is adversely affected, which is not preferable. The weight ratio of the novolak phenol resin in the organic binder is preferably 2% by weight to 40% by weight. If it is less than 2% by weight, sufficient conductivity will not be exhibited. 40
If the content is more than 10% by weight, the viscosity increases, the workability deteriorates, and it becomes difficult to obtain sufficient strength. More preferably, the content is 5% by weight to 30% by weight.

The low molecular weight polyvalent phenol compound of the present invention includes hydroquinone, catechol, resorcin, methylhydroquinone, vinylhydroquinone, tert-butylhydroquinone, chlorohydroquinone, phenylhydroquinone, 1,2,4-benzene Triol, Pyrogallo
And phloroglysin are used alone or in combination of two or more. Hydroquinone is particularly preferred for obtaining a composition having high strength and high conductivity. The weight ratio of the low molecular weight phenol in the organic binder is 5% by weight to 50% by weight.
Is preferred. If it is less than 5% by weight, sufficient conductivity will not be exhibited. If it exceeds 50% by weight, the adhesiveness and the electrical conductivity are lowered, and the water absorbency of the paste is increased. More preferably, the content is 10% by weight to 40% by weight.

The conductive adhesive of the present invention requires a curing agent to cure at a practical temperature and time. Examples of the curing agent include aliphatic polyamines such as triethylenetetramine, and examples of the aromatic amines include m-xylenediamine, m-phenylenediamine and diaminodiphenylsulfone, and examples of the tertiary amines include benzyldimethylamine. , Dimethylaminomethylpheno-
Examples of acid anhydrides include phthalic anhydride and hexahydrophthalic anhydride, and examples of boron trifluoride amine complex include boron trifluoride-piperidine complex. Alternatively, a bisphenol compound such as bisphenol A may be used. Also, dicyandiamide, 2-ethyl-4-methylimidazole, tris (methylamino) silane and the like can be mentioned. These may be used alone or in combination of two or more. The addition amount of the curing agent differs depending on the type of the curing agent. For example, when reacting with a glycidyl group like an acid anhydride, the optimum addition amount is determined from the epoxy equivalent. Moreover, when reacting catalytically, it is generally 1% by weight to 30% by weight. When these curing agents have high reactivity at room temperature, a liquid containing the curing agent can be mixed with the conductive adhesive immediately before use, or the microcapsules in which the curing agent is encapsulated in a capsule such as gelatin can be used. .

The conductive adhesive used in the present invention includes known curing accelerators, flame retardants, leveling agents, thixotropic agents, anti-settling agents, silane coupling agents, titanium coupling agents, aluminum coupling agents, and pigments. Various physical properties such as an antifoaming agent and a tackifier can be added to improve various physical properties. The conductive adhesive of the present invention can be obtained by kneading the above-mentioned various components by using a kneader such as a ball mill, a roll mill, a planetary mixer or the like by a conventional method, for example, for 10 to 60 minutes.

When the solid novolak type phenol resin is mixed with the liquid epoxy compound, it is also effective to previously heat and mix at an appropriate temperature. An optimal method for bonding and bonding an electronic component using the conductive adhesive can be selected according to conditions such as the shape of the substrate and the electronic component. For example, when a surface mounting component is fixedly joined, a paste of a conductive adhesive is applied in advance to a component connection portion (hereinafter referred to as a pad) of the wiring board by a screen printing method, a dispenser method, or the like. The mounting electrode can be obtained by pressing the bonding electrode portion of the electronic component onto the pad by pressing it from above the applied paste, drying it if necessary, and then heating and curing. The drying temperature is generally in the range of 40 ° C to 90 ° C. The curing temperature can be set to the optimum condition of the thermosetting resin to be used.
30 ° C to 220 ° C is common. The drying time varies depending on the drying temperature, but is generally within 2 hours.

Further, a conductive adhesive paste is applied to the bonding electrode portion of the electronic component in advance by printing or dipping, and dried if necessary. The conductive adhesive paste is applied to the wiring pad portion in the same procedure as described above. The adhesive paste may be adhered to the adhesive paste to be fixedly connected, and the adhesive strength is more favorable and preferable. In this case, since the electrodes are formed on the component terminal portions by using a conductive adhesive, it is possible to omit a conventional process such as plating for forming terminal electrodes. Drying is preferably performed under mild conditions because the generation of voids can be suppressed.
Further, after preliminary curing after drying, a check of continuity and the like is performed, and if a defect is found, the component can be peeled off and re-adhered. Further, even if a connection failure is found after curing, it is possible to peel and connect again.

The conductor of the wiring board may be a wiring circuit formed by patterning copper foil, or a wiring circuit formed by silver powder, copper powder and the conductive adhesive of the present invention. Copper, tinned copper, aluminum,
Silver, palladium, silver-palladium, gold, platinum, nickel, fluorine-doped tin oxide, solder, solder-plated copper,
ITO glass, IO glass and the like can be used without limitation.
To obtain a highly reliable conductor, silver-palladium,
Parts made of gold and nickel electrodes are preferred.

The conductive adhesive of the present invention forms vias as conductive pastes, fills in through-holes, resistive terminal electrodes,
It can also be used for capacitors and electrodes. Use as a conductive paint is also possible.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described with reference to the following Examples and Comparative Examples. The evaluation was performed by the following method.・ Shear strength is determined by applying a conductive adhesive on a copper plate to a thickness of 70 to 10
Keep it at 0 micron, apply 2 mm wide and 2 mm long, apply 5 copper chips (2 mm x 2 mm x 1 mm) and cure at a predetermined temperature. Push the tip of the push-pull gage into the created cured product and remove the chip. Was measured by reading the intensity of the sample. The connection resistance was measured by a four-pole terminal method by attaching a measuring terminal to the copper chip and the copper plate of the above sample.・ Heat cycle test (−5)
5 ° C to 125 ° C, 30 minutes each)
Evaluation was made based on the fluctuation rate after 00 cycles.

[0023]

Example 1 (1) Preparation of copper-containing metal filler A copper-containing metal filler was obtained by the following method. Copper powder (purity 9
(9.9%) 720 g, silver powder (purity 99.9%) 180 g
, Mixed in a graphite crucible (with a boron nitride nozzle), and melted by high-frequency induction heating under an argon atmosphere,
Heated to 1600 ° C. This melt was ejected from the nozzle under argon atmospheric pressure for 30 seconds. At the same time, argon gas in cylinder (cylinder pressure 150 atm) 4.2 NTPm
³ was ejected from the surrounding nozzle toward the melt ejected. Observation of the obtained powder with a scanning electron microscope (S-900, manufactured by Hitachi, Ltd.) revealed that the powder was spherical (average particle size: 19.6 microns). The silver concentration on the powder surface was analyzed using XPS (XSAM800 manufactured by KRATOS). As a result, the atomic ratio of Ag / (Ag + Cu) was 0.50.
Met. The silver concentration on the surface of the copper-containing metal filler was 3.5 times the average silver concentration. Of the obtained copper-containing metal filler, powder having a diameter of 20 μm or less was classified and extracted, and used for preparing paste.

(2) Preparation and evaluation of conductive adhesive 6.1 parts by weight of bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular epoxy compound (100MF manufactured by Kyoeisha Chemical Co., Ltd.) ) 1.
9 parts by weight, novolak-type phenol resin (Showa Kobunshi
9.5 parts by weight of a solution obtained by mixing 1.5 parts by weight of BRG555 (manufactured by K.K.) at 50 ° C., 3.2 parts by weight of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.), and stearic acid (Wako Pure Chemicals, Inc.) A paste obtained by kneading 0.3 part by weight of the copper-containing metal filler obtained in the above (1) and 85.9 parts by weight of the copper-containing metal filler obtained in the above (1) with three rolls is mixed with a microcapsule type epoxy curing agent. One part by weight of NOVACURE HX3741 (manufactured by Asahi Kasei Corporation) was added and kneaded with a metal spatula for 5 minutes. After joining the parts as described above using this conductive adhesive,
After preheating for 0 minutes, cure at 180 ° C for 30 minutes,
Evaluation was performed by the above method. Shear strength is 8kgf, resistance is 10
mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%. Strength and conductivity,
It is a conductive adhesive with stability.

[0025]

Example 2 6.1 parts by weight of a bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular epoxy compound (15 manufactured by Kyoeisha Chemical Co., Ltd.)
NP) (1.9 parts by weight) and 1.5 parts by weight of a novolak type phenol resin (BRG555, manufactured by Showa Polymer Co., Ltd.)
9.5 parts by weight of the solution obtained by mixing at 0 ° C., 3.2 parts by weight of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.) A paste obtained by kneading 85.9 parts by weight of the copper-containing metal filler obtained in Example 1 with three rolls was added to Novacure HX3741 (a product of Asahi Kasei Kogyo Co., Ltd.) which is a microcapsule type epoxy curing agent.
Was added and kneaded with a metal spatula for 5 minutes. After joining the parts as described above using this conductive adhesive, 8
After preheating at 0 ° C. for 10 minutes, it was cured at 180 ° C. for 30 minutes and evaluated by the above method. The shear strength was 7 kgf and the resistance was 8 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%. It is a conductive adhesive that has both strength, conductivity, and stability.

[0026]

Example 3 6.1 parts by weight of a naphthalene type epoxy resin (HP4032D manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular weight epoxy compound (100MF manufactured by Kyoeisha Chemical Co., Ltd.)
1.9 parts by weight of 9.5 parts by weight of a solution obtained by mixing 1.5 parts by weight of a novolak type phenol resin (BRG555 manufactured by Showa Polymer Co., Ltd.) at 50 ° C. and hydroquinone (Wako Pure Chemical Industries, Ltd.) 3.2 parts by weight), 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 85.9 parts by weight of the copper-containing metal filler obtained in Example 1 above are kneaded with three rolls. 1 part by weight of Novacure HX3741 (manufactured by Asahi Kasei Kogyo Co., Ltd.), which is a microcapsule type epoxy curing agent, was added to the paste thus obtained, and the mixture was kneaded with a metal spatula for 5 minutes. The parts were joined as described above using this conductive adhesive, preheated at 80 ° C. for 10 minutes, cured at 180 ° C. for 30 minutes, and evaluated by the above method. The shear strength was 7 kgf and the resistance was 10 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%. It is a conductive adhesive that has both strength, conductivity, and stability.

[0027]

Example 4 6.1 parts by weight of a bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular weight epoxy compound (10 manufactured by Kyoeisha Chemical Co., Ltd.)
0MF), 1.9 parts by weight, and 1.5 parts by weight of novolak phenol resin (BRG555, manufactured by Showa Polymer Co., Ltd.)
9.5 parts by weight of the solution obtained by mixing at 0 ° C., 3.2 parts by weight of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.), 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.), metal filler Copper powder (FCC-SP-99 manufactured by Fukuda Metal Foil Industry Co., Ltd.) 7
To a paste obtained by kneading 6.0 parts by weight with three rolls,
Novacure H, a microcapsule type epoxy curing agent
X3741 (manufactured by Asahi Chemical Industry Co., Ltd.) was added by 1 part by weight, and kneaded with a metal spatula for 5 minutes. The parts were joined as described above using this conductive adhesive, preheated at 80 ° C. for 10 minutes, cured at 180 ° C. for 30 minutes, and evaluated by the above method. The shear strength was 10 kgf and the resistance was 10 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%. It is a conductive adhesive that has both strength, conductivity, and stability.

[0028]

Example 5 Low molecular epoxy compound (Kyoeisha Chemical Co., Ltd.)
6.9 parts by weight, novolak type phenol
2.4 parts by weight of resin (BRG555 manufactured by Showa Polymer Co., Ltd.) and 0.0 parts of phenoxy resin (PKHC manufactured by PAPHEN).
9.6 parts by weight of a solution obtained by mixing 3 parts by weight at 50 ° C., 2.2 parts by weight of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.) Parts, 86.4 parts by weight of the copper-containing metal filler obtained in Example 1 above
To the paste obtained by kneading the mixture, 1.5 parts by weight of NOVACURE HX3741 (manufactured by Asahi Kasei Kogyo Co., Ltd.), which is a microcapsule type epoxy curing agent, was added and kneaded with a metal spatula for 5 minutes. After joining the parts as described above using this conductive adhesive, preheating at 80 ° C. for 10 minutes and then 180 ° C.
And cured for 30 minutes, and evaluated by the above method. The shear strength was 7 kgf and the resistance was 5 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%. It is a conductive adhesive that has both strength, conductivity, and stability.

[0029]

Example 6 6.1 parts by weight of a bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular weight epoxy compound (10 manufactured by Kyoeisha Chemical Co., Ltd.)
0MF), 1.9 parts by weight, and 1.5 parts by weight of novolak phenol resin (BRG555, manufactured by Showa Polymer Co., Ltd.)
9.5 parts by weight of the solution obtained by mixing at 0 ° C., 3.2 parts by weight of methylhydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.), 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.), A paste obtained by kneading 85.9 parts by weight of the copper-containing metal filler obtained in Example 1 with three rolls was mixed with Novacure HX3741 as a microcapsule type epoxy curing agent (Asahi Chemical Industry Co., Ltd.).
1 part by weight) and kneaded with a metal spatula for 5 minutes. The parts were joined as described above using this conductive adhesive, preheated at 80 ° C. for 10 minutes, cured at 180 ° C. for 30 minutes, and evaluated by the above method. Shear strength is 7kg
f, the resistance was 10 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test was within 20%.
It is a conductive adhesive that has both strength, conductivity, and stability.

[0030]

Comparative Example 1 6.1 parts by weight of a bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and an epoxy compound (1500N manufactured by Kyoeisha Chemical Co., Ltd.)
P) 9.5 parts by weight of a solution obtained by mixing 1.9 parts by weight, 1.5 parts by weight of a resole type phenol resin at 50 ° C., and 3.2 of hydroquinone (manufactured by Wako Pure Chemical Industries, Ltd.) 3.2 Parts by weight, 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 85.9 parts by weight of the copper-containing metal filler obtained in Example 1 were kneaded with three rolls. To the strike, 1 part by weight of Novacure HX3741 (manufactured by Asahi Kasei Kogyo Co., Ltd.), which is a microcapsule-type epoxy curing agent, was added and kneaded with a metal spatula for 5 minutes. The parts were joined as described above using this conductive adhesive, preheated at 80 ° C. for 10 minutes, cured at 180 ° C. for 30 minutes, and evaluated by the above method. The shear strength was 3 kgf, and the fluctuation in strength after the heat cycle test was 1
It is a conductive adhesive with a low strength of 00% and poor strength stability.

[0031]

Comparative Example 2 6.1 parts by weight of a bisphenol A type epoxy resin (EXA850CRP manufactured by Dainippon Ink and Chemicals, Inc.) and a low molecular weight epoxy compound (10 manufactured by Kyoeisha Chemical Co., Ltd.)
0MF), 1.9 parts by weight, and 1.5 parts by weight of novolak phenol resin (BRG555, manufactured by Showa Polymer Co., Ltd.)
9.5 parts by weight of the solution obtained by mixing at 0 ° C., 0.3 parts by weight of stearic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and 85.9 parts by weight of the copper-containing metal filler obtained in Example 1 were mixed with 3 parts by weight. The paste obtained by kneading with this roll was mixed with a microcapsule type epoxy curing agent Novacure HX3741 (Asahi Kasei Kogyo Co., Ltd.)
1 part by weight) and kneaded with a metal spatula for 5 minutes. The parts were joined as described above using this conductive adhesive, preheated at 80 ° C. for 10 minutes, cured at 180 ° C. for 30 minutes, and evaluated by the above method. Shear strength is 4kg
f, the resistance was 300 mΩ. Furthermore, the rate of change in resistance and strength after the heat cycle test is as low as 100%,
It is a conductive adhesive with high resistance and poor stability.

[0032]

The conductive adhesive of the present invention has sufficient adhesive strength and conductivity to withstand practical use, and has little variation in these characteristics due to environmental tests, so that it is very useful in industry.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J040 EB052 EC031 EC061 EC071 EC081 EC121 EC151 EC211 EC241 EC251 EC281 HA066 HB36 HB37 HB38 HB44 HB47 HC02 HC08 HC16 HC24 HD36 HD43 JA05 KA05 KA16 KA32 LA06 LA09 MA02 NA19 NA20

Claims (2)

[Claims] 1. A metal filler containing at least 50% by weight to 100% by weight of copper, an epoxy compound,
A conductive adhesive comprising a novolak type phenol resin, a low molecular weight polyvalent phenol and a curing agent. 2. The conductive adhesive according to claim 1, wherein the low molecular polyvalent phenol is hydroquinone.