JP2002008442A - Thermo setting low resistant conductive paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems of usual conductive paste materials related to conductivity of paste to become fairly low after coating in comparison with original conductivity of metal, which is origin of the metal powder, caused by a contact state among metal powder as conductive material being kept in solid contact or ohmic contact and related to heat resistance of solder after coating caused by usage of resin as base material of paste material. SOLUTION: The base material is made by kneading Ga liquid metal of liquid state at room temperature and blending materials such as synthetic resin e.g. phenol, epoxy or acrylic resin and non-metal. A material made of the base material and filler powder treated with coating for prevention of diffusion on its surface is kneaded, and the kneaded material is cured by heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting low-resistance conductive paste used for joining components such as a base material.

[0002]

2. Description of the Related Art Conventionally, a material used as a conductive paste is a mixture of a metal powder as a conductive material, a resin for fixing on a material to be coated, and a resin solvent.

[0003]

In such a conductive paste material, the contact state between the metal powders as the conductive material is a solid contact, that is, an ohmic contact. There is a problem that the conductivity is several steps lower than the original conductivity of the powder metal.

[0004] For this reason, the conventional conductive paste material has a problem in that the amount of application must be increased in order to obtain a predetermined conductivity because the conductivity is low as described above.
Further, since a resin is used as a base material of the paste material, there is a problem in solder heat resistance after application.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an aggregate powder comprising a metal powder having a diffusion-preventing coating on its surface or a metal powder having a non-metallic core alone or as a mixed powder. In order to prevent the diffusion reaction due to direct contact between the body and the Ga-based liquid metal that is in a liquid state at normal temperature, and to prolong the clogging use time, a paste-like synthetic resin such as a phenol-based, epoxy-based, or acrylic-based resin is used. Metal as admixture,
This admixture and a Ga-based liquid metal are kneaded and used as a base material, and a resin having thermoplasticity such as rosin resin, acrylic resin, vinyl chloride resin or waxes represented by paraffin, lauric acid, stearic acid A powder having a coating made of a heat-fusible organic compound such as a higher fatty acid is used as an aggregate powder, and the aggregate powder and the above-described base material are mixed and kneaded.

The admixture is basically glue-like,
It may be replaced with solid synthetic resin powder or nonmetal powder. Further, Ga-based liquid metal in a liquid state at normal temperature is In-Ga,
It has a composition such as Sn-Ga, Ag-Ga, In-Sn-Ga, etc., and has an affinity for most solid substances except for a fluorine resin, a silicon resin and the like.

The core portion of the metal powder having a non-metallic core is made of a material having at least one of a metal oxide such as alumina and magnesia, carbon or a carbon compound, glass, ceramics and synthetic resin. The outer periphery of the metal occupying the outer periphery of the core has a coating for preventing a diffusion reaction like the metal powder. The present invention provides a metal powder having a paste-like phenol-based, epoxy-based, acrylic-based synthetic resin admixture for preventing a diffusion reaction and a coating for preventing a diffusion reaction, or a coating for preventing a diffusion reaction. A paste material comprising at least one kind of metal powder having a non-metal core having a non-metal core and a Ga liquid metal in a liquid state at room temperature. The coating of the metal powder thus broken or melted and comes into direct contact with the Ga liquid metal, whereby a diffusion reaction occurs and the solidification and fusion occur.

The conductivity according to the present invention is obtained by a diffusion reaction between the powder metal and the Ga liquid metal. The conductivity is several steps higher than the conventional conductivity by ohmic contact between metal powders. Shows sex. Further, the present invention can set the heating temperature with good workability by selecting the metal powder composition and the composition of the Ga liquid metal, and by selecting the mixing ratio of the metal powder having a non-metal core. It becomes a paste material that can design free conductivity and compatibility with the substrate.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment 10 g of a pasty phenol resin and a composition of 63% Ga-12% S
30 g of a liquid alloy (melting point 15 ° C.) of n-25% In is mechanically kneaded, and further, 95% Ag-5% having an average particle size of 2 μm.
50 g of Cu powder and 20 g of Ag-coated glass beads having a maximum particle size of 40 μm or less, using a 5% concentration of stearic acid, mechanically mix and knead the powder coated with stearic acid to form a paste and did.

This paste was applied to a glass epoxy substrate in a predetermined size, heated at 90 ° C. and cured, and the resistance was measured. Second Embodiment Example A coated with lauric acid and having an average particle size of 2 μm
g powder, weight ratio of 1, paste-like phenolic resin 0.2 by weight ratio, maximum particle size 4 coated with lauric acid
Ag-coated glass beads of 0 μm or less are 0.4 by weight ratio,
A liquid alloy having a composition of 63% Ga-12% Sn-25% In was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

This paste was applied to a glass epoxy substrate in a predetermined size, heated at 120 ° C. and cured, and the resistance was measured. Third Embodiment 7 coated with rosin resin and having an average particle size of 2 μm
2% Ag-28% Cu powder is 1 in a weight ratio, paste-like epoxy resin is 0.2 in a weight ratio, and rosin resin-coated Ag-coated carbon powder having a maximum particle size of 40 μm or less is 0.4 in a weight ratio. A liquid alloy having a composition of 75% Ga-25% In was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

This paste was applied to a glass epoxy substrate in a predetermined size, heated at 180 ° C. and cured, and the resistance was measured. Fourth Embodiment A 50% Ag-50% Cu powder having an average particle size of 2 μm coated with a benzotriazole resin and having a weight ratio of 1
A having a maximum particle size of 40 μm or less coated with a glue-like epoxy resin 0.2 by weight and a benzotriazole resin
g coated carbon powder in a weight ratio of 0.4, composition 75% Ga-25
% In liquid alloy was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

This paste was applied to a glass epoxy substrate with a predetermined size, heated at 160 ° C. and cured, and the resistance was measured. Fifth Embodiment Example 9 coated with caproic acid and having an average particle size of 2 μm
8% Ag-2% Sn powder is 1 in weight ratio, paste-like epoxy resin is 0.2 in weight ratio, Ag-coated alumina powder coated with caproic acid and having a maximum particle size of 40 μm or less is 0.4 in weight ratio, A liquid alloy having a composition of 86% Ga-14% Sn was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

The paste was applied to a glass epoxy substrate with a predetermined size, heated at 95 ° C., cured, and the resistance was measured. Sixth Embodiment 9 having an average particle size of 2 μm coated with caprylic acid
8% Ag-2% Zn powder is 1 in weight ratio, glue-like acrylic resin is 0.2 in weight ratio, Ag-coated alumina powder coated with caprylic acid and having a maximum particle size of 40 μm or less is 0.4 in weight ratio, A liquid alloy having a composition of 86% Ga-14% Sn was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

This paste was applied to a glass epoxy substrate in a predetermined size, heated at 110 ° C. and cured, and the resistance was measured. Seventh Embodiment Paraffin-coated 9 having an average particle size of 2 μm
5% Ag-3% Cu-2% Sn powder is 1 in weight ratio, paste-like acrylic resin is 0.2 in weight ratio, and paraffin-coated Ag-coated alumina powder having a maximum particle size of 40 μm or less is 0 in weight ratio. And a liquid alloy having a composition of 96% Ga-4% Ag was mechanically mixed and kneaded at a weight ratio of 0.6 to obtain a paste.

This paste was applied to a glass epoxy substrate at a predetermined size, heated at 150 ° C. and cured, and the resistance was measured. Eighth Embodiment 10 g of a pasty phenol resin and a composition of 63% Ga-12% S
20 g of a liquid alloy (melting point 15 ° C.) of n-25% In is mechanically kneaded, and further, 95% Ag-5% with an average particle size of 2 μm
A paste obtained by mechanically mixing and kneading 50 g of a Cu powder with a powder surface coated with stearic acid using a 5% concentration of stearic acid was used.

After this paste was applied to a glass epoxy substrate in a predetermined size, the paste was heated to 90 ° C. to be cured, and the resistance was measured. Ninth Embodiment A rosin resin-coated 7 having an average particle size of 2 μm
2% Ag-28% Cu powder is 1 in weight ratio, paste-like epoxy resin is 0.2 in weight ratio, composition is 75% Ga-25% In.
Was mechanically mixed and kneaded at a ratio of 0.4 by weight to obtain a paste.

After this paste was applied to a glass epoxy substrate in a predetermined size, the paste was heated to 180 ° C. to be cured, and the resistance was measured. Tenth Embodiment Example 9 coated with caproic acid and having an average particle size of 2 μm
8% Ag-2% Sn powder is mechanically at a weight ratio of 1, paste-like acrylic resin is 0.2 at a weight ratio, and 86% Ga-14% Sn liquid alloy is 0.4 at a weight ratio of mechanically mechanical. And kneaded into a paste.

After this paste was applied to a glass epoxy substrate in a predetermined size, the paste was heated to 95 ° C. and cured, and the resistance was measured. Eleventh embodiment 10 g of a pasty phenol resin and a composition of 63% Ga-12% S
20 g of an n-25% In liquid alloy (melting point 15 ° C.) is mechanically kneaded, and 50 g of Ag-coated glass beads having a maximum particle size of 40 μm or less are stearic acid having a concentration of 5%.
The powder surface coated with lauric acid was mechanically mixed and kneaded to obtain a paste.

This paste was applied to a glass epoxy substrate at a predetermined size, heated at 90 ° C. and cured, and the resistance was measured. Twelfth Embodiment A weight ratio of Ag-coated carbon powder having a maximum particle size of 40 μm or less coated with a benzotriazole resin to a weight ratio of 1, a paste epoxy resin of 0.2 by weight, and a composition of 75% Ga-25
% In liquid alloy was mechanically mixed and kneaded at a weight ratio of 0.4 to obtain a paste.

The paste was applied to a glass epoxy substrate with a predetermined size, heated at 160 ° C. and cured, and the resistance was measured. Thirteenth Embodiment The weight ratio of Ag-coated alumina powder having a maximum particle size of 40 μm or less coated with caprylic acid is 1, the paste-like acrylic resin is 0.2 in weight ratio, and the composition is 86% Ga-14% Sn.
Was mechanically mixed and kneaded at a ratio of 0.4 by weight to obtain a paste.

After this paste was applied to a glass epoxy substrate with a predetermined size, the paste was heated to 110 ° C. and cured, and the resistance was measured. As a conventional example to be compared with each of the above embodiments, a metal powder made of Ag having an average particle diameter of 2 μm is a weight ratio of 1, an epoxy resin is a weight ratio of 0.2, and a curing agent is a weight ratio of 0.1. After mixing and applying with the same dimensions as in each of the above embodiments, the resistance value was measured after a heat treatment at 150 ° C.

Regarding each of the above embodiments and the conventional example,
After measuring the electrical resistance, the results are shown in Table 1 by comparing the solder heat resistance and the pot life.

[0024]

[Table 1]

[0025]

According to the present invention described in detail above, the paste material of the present invention has a long pot life and does not contain a resin solvent as in the prior art. There is no foaming caused by the above, and there is an effect that the workability is excellent. In addition, it becomes an excellent paste material exhibiting extremely stable and low-resistance conductivity.

As a result of these effects, it is possible to flexibly design various kinds of substrate materials, heat treatment conditions and the like, and to provide low-resistance conductivity.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 61/04 C08L 61/04 63/00 63/00 C H01B 1/00 H01B 1/00 M 1/16 1/16 Z (72) Inventor Michihiko Nishijima 2-9-1-12 Kaji-cho, Chiyoda-ku, Tokyo Inside the Tokuriki Head Office (72) Inventor Koichi Sayama 2-9-12 Kaji-cho, Chiyoda-ku, Tokyo Stock Association Inside the Shatoku Riki Chemical Laboratory (72) Inventor Junki Miyauchi 2-9-12 Kaji-cho, Chiyoda-ku, Tokyo F-term (reference) 4K002 BG021 CC021 CC121 CD001 DA017 DA067 DA068 DA077 DA116 DB017 DC007 DE077 DE147 DL007 DM007 FB077 FB087 FB267 GQ02 HA08 5G301 DA02 DA03 DA06 DA13 DA29 DA42 DA55 DA57 DD01 DE01

Claims (8)

[Claims] 1. A kneaded mixture of a Ga-based liquid metal in a liquid state at room temperature, a phenol-based, epoxy-based, acrylic-based synthetic resin or a non-metallic admixture, and using this as a base material, Mix with aggregate powder whose surface has a coating to prevent diffusion.
A thermosetting low-resistance conductive paste, which is kneaded and cured by heating the mixed kneaded material. 2. The Ga-based liquid metal according to claim 1, wherein 1 to 25% of In, 1 to 15% of remaining Ga, Sn, 1 to 6% of remaining Ga, 1 to 6% of remaining Ga, and 1 to 45% of remaining Ga.
%, Sn 13.6 to 30%, and the balance of Ga in any one of the composition ranges. 3. The thermosetting low-resistance conductive paste according to claim 1, wherein the aggregate powder is metal powder. 4. The thermosetting low-resistance conductive paste according to claim 1, wherein the aggregate powder is a non-metal core composite powder having a metal layer formed on the outer periphery. 5. The non-metal core composite powder according to claim 4, wherein the core material is at least one of metal oxides such as alumina and magnesia, carbon or carbon compound, glass, ceramics and synthetic resin. Thermosetting low resistance conductive paste. 6. The method according to claim 1, wherein the aggregate powder is a mixed powder of a metal powder and a non-metal core composite powder having a metal layer formed on the outer periphery, and the proportion is 5 to 60% by weight of the metal powder. A thermosetting low-resistance conductive paste comprising 40 to 95% of a non-metal core composite powder. 7. The thermosetting low-resistance conductive paste according to claim 3, wherein the metal powder is at least one of Ag and Ag alloy. 8. The method according to claim 1, wherein the coating for preventing diffusion formed on the surface of the aggregate powder is represented by a natural or synthetic resin having thermoplasticity such as rosin resin, acrylic resin, vinyl chloride resin or paraffin. A thermosetting low-resistance conductive paste comprising an organic compound of a higher fatty acid such as wax, lauric acid and stearic acid.