JP3219852B2 - Conductive paste - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive paste having excellent adhesiveness, bleeding resistance and migration resistance, which is used for assembling semiconductor devices and bonding various components.

[0002]

2. Description of the Related Art In general, a conductive paste is composed of a thermosetting binder such as an epoxy resin and a conductive powder and the like.
It is applied to circuit formation by printing. The thermosetting resin of the binder is thermally cured by the curing agent, becomes insoluble in the organic solvent, and is given heat resistance, moisture resistance, weather resistance, and the like.
As the curing agent for the binder epoxy resin, a wide variety of polyamide resins, amines, melamines, acid anhydrides, boron trifluoride, amine complexes and the like are used.

[0003]

It is known that when these conductive pastes are bonded or dipped, the solvent in the conductive paste causes bleeding at the interface with the adherend. During this bleeding, especially when fine conductive powder in the conductive paste oozes out, migration is extremely likely to occur when a voltage is applied under high temperature and high humidity conditions, which significantly reduces the reliability of electronic components. There was a problem of lowering.

The present invention has been made in view of the above circumstances, and has a novel property which is excellent in adhesiveness, improves bleeding resistance, prevents bleeding of fine conductive powder, and can prevent migration. It is intended to provide a conductive paste.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the above object can be achieved by using a paste having a composition described later. It is completed. That is, the present invention relates to (A) (a) a bisphenol A novolak resin, (b) an epoxy resin, and (c) a fluorine-containing compound represented by the general formula (2).

[0006]

Embedded image

[0007] A conductive paste comprising, as essential components, a mixed resin comprising: (B) a composite powder comprising a conductive powder and a fine silica powder; and (C) a porous filler.

Hereinafter, the present invention will be described in detail.

The mixed resin (A) used in the present invention comprises (a)
Bisphenol A novolak resin, (b) epoxy resin
And (c) fluorine-containing compound shown by the general formalized 2 Tona
Things .

The bisphenol A novolak resin (a) used in the present invention is a resin represented by the following general formula 3.

[0011]

Embedded image (Wherein, m and n represent 0 or a positive integer) Examples of the specific resin include Plyofen VH-4170
(Trade name, manufactured by Dainippon Ink and Chemicals, Inc.), and the softening point of Plyofen VH-4170 is 103 to 108 ° C.,
The hydroxyl equivalent is about 118. The resin having such a structure improves the heat resistance, room-temperature adhesive strength, hot adhesive strength, and adhesiveness of the cured paste or the coating film in the composition of the present invention.

(B) As the epoxy resin, for example, Epicoat 827, 828, 834, 1001, 1002,
1007, 1009 (manufactured by Shell Chemical Company, trade name), DE
R330,331,332,334,335,336,
337, 383, 660 (manufactured by Dow Chemical Company, trade name), Araldite GY250, 260, 280, 60
71, 6084, 6097, 6099 (trade name, manufactured by Ciba Geigy), EPI-REZ510, 5101 (JO
NE DABNEY, trade name), Epicron 81
0, 1000, 1010, 3010 (manufactured by Dainippon Ink and Chemicals, Inc., trade name), EP series manufactured by Asahi Denka Co., Ltd. and the like. Furthermore, by using an average number of epoxy groups of 3 or more, for example, a novolak epoxy resin, heat (350 ° C.)
Can be further improved. As these novolak epoxy resins, those having a molecular weight of 500 or more are suitable. Examples of industrially produced novolak epoxy resins include the following. Araldite EPN1138, 1139, EC
N1273, 1280, 1299 (manufactured by Ciba Geigy,
(Trade names), DEN431, 438 (trade name, manufactured by Dow Chemical Company), Epicoat 152, 154 (trade name, manufactured by Shell Chemical Company), ERR-0100, ERRB-044
7, ERLB-0488 (manufactured by Union Carbide, trade name), EOCN series (manufactured by Nippon Kayaku Co., Ltd.), etc., and these epoxy resins can be used alone or in combination of two or more. .

As the fluorine-containing compound (c), those represented by the following general formula 4 are used.

[0014]

Embedded image

This fluorinated compound is characterized by having a perfluoromethyl group, and is reacted with an epoxy resin or a bisphenol A novolak resin by a functional group X or Y to be incorporated into a cured product to form a conductive paste. Provides bleeding resistance and migration resistance. The mixing ratio of this fluorine-containing compound is
It is desirable that the amount be 5 to 20 parts by weight based on 00 parts by weight.
If the amount is less than 5 parts by weight, there is no effect on bleeding resistance and migration resistance, and if it exceeds 20 parts by weight, the cured film becomes brittle, cannot relax stress, and lacks reliability as an adhesive. .

The above-mentioned bisphenol A novolac resins, epoxy resins, that the fluorine-containing compound dissolved mixture of <br/> a solvent. Et al is, it is possible to improve the working viscosity by dissolving in a common solvent for these resin components. As the solvent used here, dioxane, hexane, toluene, ethyl cellosolve, cyclohexanone, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, diethylene glycol diethyl ether, dimethylformamide, N-methylpyrrolidone, diacetone alcohol, dimethylacetamide, γ-butyrolactone, Examples thereof include 1,3-dimethyl-2-imidazolidinone, and these can be used alone or in combination of two or more.

The (B) composite powder used in the present invention includes:
The conductive powder and the fine silica powder are used in combination. Examples of the conductive powder include silver powder, powder having a silver layer on the surface, copper powder, nickel powder, and carbon. These can be used alone or in combination of two or more. Examples of the fine silica powder include, for example, Aergil (trade name, manufactured by Nippon Aergil Co., Ltd.) having an average particle size of 1 μm or less.

As the porous filler (C) used in the present invention, any porous filler can be used without particular limitation. Specific examples include, for example, Talsite (trade name, manufactured by Kyowa Gas Chemical Co., Ltd.), Ketjen Black (Ketje Black)
n company carbon black (trade name), Celite (Johns
Diatomaceous earth manufactured by Manville, Inc.)
These can be used alone or in combination of two or more.

The conductive paste of the present invention contains the above-mentioned mixed resin, composite powder and porous filler as essential components, but as long as the object of the present invention is not adversely affected, and if necessary, an antifoaming agent , A coupling agent, and other additives. After thoroughly mixing the above-mentioned components according to a conventional method,
Further, the conductive paste can be produced by kneading with a three-roll mill and then defoaming under reduced pressure. The conductive paste thus produced can be used for bonding, coating, and forming electrodes by printing, forming circuits, and the like of various electronic components.

The conductive paste of the present invention comprises a bisphenol A novolak resin, an epoxy resin, a mixed resin comprising a fluorine-containing compound having a perfluoromethyl group represented by the above general formula, a conductive powder and a fine silica powder. The object has been achieved by using a composite powder and a porous filler. In particular, by incorporating the compound of the above general formula into the mixed resin and introducing a perfluoromethyl group, the excellent heat resistance, chemical resistance and water repellency possessed by fluorine are imparted, and the surface tension is lowered. The wettability to an adhesive or an object to be coated can be improved, and as a result, the adhesiveness and adhesion of the conductive paste can be improved. Further, the compound can be reacted with a bisphenol A novolak resin or an epoxy resin to impart bleeding resistance or migration resistance.

[0021]

Next, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 Epicoat 828 of epoxy resin (trade name, manufactured by Yuka Shell Epoxy Co., Ltd.) 100 parts, Plyofen VH-4170 of bisphenol A novolak resin (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) 63 parts and General formula

[0023]

Embedded image 15 parts of the compound BIS-AF-G (trade name, manufactured by Central Glass Co., Ltd.) was dissolved in 386 parts of butyl cellosolve acetate by heating at 100 ° C. for 1 hour to obtain a viscous resin.
To 26.8 parts of this resin, 1.2 parts of an amine complex of boron trifluoride as a catalyst, 0.05 parts of an additive, 69.4 parts of silver powder, 2.4 parts of AERYL # 200 (trade name, manufactured by Nippon AERYL Co., Ltd.) as fine silica powder, and Talcite (Kyowa) A conductive paste was manufactured by mixing 0.1 part of a gas (trade name, manufactured by Gas Co., Ltd.).

Example 2 100 parts of an epoxy resin epicoat 1001 (trade name, manufactured by Yuka Shell Epoxy Co.), 24 parts of bisphenol A novolak resin Plyofen VH-4170 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) General formula

[0025]

Embedded image Compound BIS-A-AF (trade name, manufactured by Central Glass Co., Ltd.) (10 parts) was dissolved in 290 parts of diethylene glycol diethyl ether by heating at 100 ° C. for 1 hour to obtain a viscous resin. As a catalyst, 26.8 parts of the resin, 1.2 parts of an amine complex of boron trifluoride, 0.12 parts of an additive, and 69.4 parts of silver powder
And 2.4 parts of AEROSIL # 200 (trade name, manufactured by Nippon AERYL Co., Ltd.) as fine silica powder, and 0.1 parts of Ketjen Black (trade name, manufactured by Ketjen) were mixed to prepare a conductive paste.

Example 3 Epoxy resin EOCN103S (trade name, manufactured by Nippon Kayaku Co., Ltd.) 100 parts, bisphenol A novolak resin Plyofen VH-4170 (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) 26 parts and a general formula

[0027]

Embedded image 15 parts of the compound BIS-AF (trade name, manufactured by Central Glass Co., Ltd.)
The mixture was heated and dissolved in 151 parts at 100 ° C for 1 hour to obtain a viscous resin. An imidazole compound 2 was used as a catalyst in 30 parts of this resin.
pH-CN (trade name, manufactured by Shikoku Chemical Industry Co., Ltd.) 0.1 part, additive: 0.1 part, silver powder 65 parts, Aesil® # 200 as fine silica powder (trade name, manufactured by Nippon Aesil Co., Ltd.) 0.8
And 0.1 part of Talcite (trade name, manufactured by Kyowa Gas Co., Ltd.) and 4 parts of butyl cellosolve acetate were mixed to produce a conductive paste.

Comparative Example A commercially available epoxy resin-based conductive paste for a solvent-type semiconductor was obtained.

The conductive pastes obtained in Examples 1 to 3 and Comparative Example were evaluated for adhesive strength, accelerated migration test, migration resistance, and bleeding property. The results are shown in Table 1. As shown in Table 1, the present invention was excellent, and the remarkable effects of the present invention were recognized.

[0030]

[Table 1] * 1: 2.0x on silver-plated lead frame (copper)
A 2.0 mm silicon device was adhered and measured at 25 ° C. using a tension gauge. * 2: 2.0x on a silver-plated lead frame (copper)
A 2.0 mm silicon element is adhered, 121 ° C x 100% R. H
After the treatment at × 2 atm × 24 hours, the measurement was carried out at 25 ° C. using a tension gauge. * 3: Conductive paste is screen-printed on a slide glass, the surface resistance is measured after curing, and converted to volume resistivity. * 4: As shown in FIG. 1, a conductive paste 2 is screen-printed on a slide glass 1 so as to provide a discontinuous part 3 having a width of 5 mm, a thickness of 20 μm and a width of 2 mm in the middle, and the width of 2 m.
Distilled water 4 was dropped into the discontinuous portion 3 of m, a DC voltage of 5 V was applied, and the time until the current leaked was measured. * 5: The test piece of * 4 was tested at a temperature of 60 ° C, a humidity of 95%, and an applied voltage D.
Observation was performed at predetermined time intervals under the condition of C30V, and the time when migration occurred for the first time was measured. * 6: The test piece of * 2 was observed 24 hours after PCT and before the measurement of the adhesive strength. ○: no bleed, △: slight bleed, ×:
There is remarkable bleed.

[0031]

As is clear from the above description and Table 1, the conductive paste of the present invention has excellent adhesiveness, migration resistance and bleeding resistance even under high temperature and high humidity conditions, and exudes conductive powder. No good. By using this conductive paste, a highly reliable electronic component can be manufactured.

[Brief description of the drawings]

FIG. 1 is a plan view of a test piece used for an accelerated migration test and a migration resistance test.

[Explanation of symbols]

 1 slide glass 2 conductive paste 3 discontinuous part 4 distilled water

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01B 1/20 H01B 1/20 A H05K 1/09 H05K 1/09 D // H05K 3/32 3/32 B (56) Reference Document JP-A-56-79150 (JP, A) JP-A-62-296449 (JP, A) JP-A-63-129114 (JP, A) JP-A-64-16867 (JP, A) 188426 (JP, A) JP-A-4-51406 (JP, A) JP-A-4-65012 (JP, A) JP-A-4-31311 (JP, A) JP-A-4-39807 (JP, A) JP-A-4-39809 (JP, A) JP-A-4-39810 (JP, A) JP-A-4-209687 (JP, A) JP-A-4-339853 (JP, A) JP-A-5-93041 (JP, A) JP-A-5-120914 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 63/00-63/10 C08K 5/03 C 08K 3/36 C08K 3/02 C08G 59/62 H01B 1/20-1/24 H05K 1/09 H05K 3/32

Claims (1)

(57) [Claims] (A) (a) a bisphenol A novolak resin, (b) an epoxy resin, and (c) a fluorine-containing compound represented by the general formula (1). A mixed resin, (B) a conductive powder and a composite powder consisting of fine silica powder, (C) a porous filler a conductive paste characterized by comprising as essential components.