JPH0439810A - Conductive paste - Google Patents

Abstract

PURPOSE:To improve adhesiveness and bleeding resistance by using a denatured resin consisting of a polypallahydroxy stylene resin and an epoxy resin. CONSTITUTION:Conductive paste essentially includes a denatured resin A consisting of a polypallahydroxy stylene resin and an epoxy resin, conductive powder and fine silica powder B and an acetate solvent C. As the denatured resin A, the polypallahydroxy stylene resin and the epoxy resin may be only dissolved into mixture, or partially connected to each other by a heating reaction. As the conductive powder and fine silica powder B, conductive powder and fine silica powder are used together. The acetate solvent C is used as one component of a solvent of the conductive paste. Therefore, it is possible to improve adhesiveness, bleeding resistance and migration resistance.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention provides a method for producing a material having excellent adhesiveness and bleeding resistance.
Used in conductive paste used for assembling electronic parts, etc.

(Prior Art) In general, conductive paste is mainly composed of a binder such as an epoxy resin and conductive powder, and is used for adhering and coating various electronic parts by containing a small amount of solvent.
A wide variety of curing agents for the epoxy resin binder are used, including polyamide resins, amines, melamines, acid anhydrides, boron trifluoride, and amine complexes.

(Problems to be Solved by the Invention) 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. especially,
When the fine conductive powder in the conductive paste oozes out during this bleeding, migration is likely to occur, causing a problem of extremely lowering the reliability of electronic components.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and is a novel product that has excellent adhesive properties, improves bleeding resistance, and prevents oozing of fine conductive powder. The purpose of this invention is to provide a conductive paste.

[Structure of the Invention j (Means for Solving the Problem) The present inventors have attempted to achieve the above object 1e! As a result of repeated research, it was found that a conductive paste with excellent adhesiveness and bleeding resistance could be obtained by using the composition described below, and the present invention was completed.

That is, the present invention provides a conductive material comprising (A) a modified resin comprising a polyparahydroxystyrene resin and an epoxy resin, (B) a conductive powder and a fine silica-based powder, and (C) an acetate-based solvent as an essential component. It is a sex paste.

The present invention will be explained in detail below.

The modified resin (A) consisting of a polyparahydroxystyrene resin and an epoxy resin used in the present invention may be obtained by simply dissolving and mixing the polyparahydroxystyrene resin and the epoxy resin, or by partially bonding them together by a heating reaction. A curing catalyst may also be used if necessary for the reaction. Furthermore, the working viscosity can be improved by dissolving these component resins in a common solvent.

The polyparahydroxystyrene resin used here is a resin represented by the following formula.

(However, in the formula, n represents an integer of 25 to 90.) Examples of such resins include Maruka Linker M (manufactured by Marukubi Petrochemical Co., Ltd., trade name), which has a molecular weight of 3000 to 800.
0 and the number of hydroxyl groups is approximately 120. Furthermore, as epoxy resins used in the modified resin, there are the following dieboxides of bisphenols, which are industrially produced and can be effectively used in the present invention. Epicor) -827, 828, 834, 1001, 1002
゜1007.1009 (manufactured by Shell Chemical Co., Ltd., trade name),
DER330, 331, 332, 3, 34, 335°3
36 337.660 (product name manufactured by Dow Chemical Company), Araldai 1-GY250.260, 280°6071
, 6084, 6 (197, 6099 (manufactured by Ciba Geigy, product name), EP I-REZ51 (1510
1 (manufactured by JONE DABNEY Co., Ltd., trade name), Epicron 810, 1000.1010°3010 (manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name), and EP series (manufactured by Asahi Denka Co., Ltd., trade name).

Furthermore, by using a novolac epoxy resin having an average number of epoxy groups of 3 or more, for example, the adhesive strength at high temperature (350° C.) can be further improved. As these novolac epoxy resins, those having a molecular weight of 500 or more are suitable. Examples of such novolac epoxy resins that are industrially produced include the following. Araldite EPN1138, 1139, E
CN1273.1280.1299 (manufactured by Ciba Power Iggy Co., Ltd., trade name), DEN431,438 (manufactured by Daughemical Co., Ltd., trade name), Epicote 152,154 (manufactured by Shell Chemical Co., Ltd., trade name), ERR-0100゜ERRB-04
47, ERLB-0488 (manufactured by Ni-Nion Carbide Co., Ltd.,
Product name), EOCN series (manufactured by Nippon Kayaku Co., Ltd., product name)
These epoxy resins can be used alone or in a mixture of two or more.

It is desirable that the modified resin consisting of polyparahydroxystyrene resin and epoxy resin be dissolved and mixed in the following solvent. Solvents that can be used here include dioxane, hexane, benzene, toluene, solvent naphtha, industrial gasoline, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carpitol acetate, diethylene glycol diethyl ether, dimethyl formamide, dimethyl acetamide, Examples include N-methylpyrrolidone, which may be used alone or in combination of two or more.

As the conductive powder and fine silica-based powder (B) used in the present invention, a conductive powder and a fine silica-based powder are used in combination. As the conductive powder, silver powder, silver-plated copper powder, copper powder, nila gel powder, carbon powder, etc. are used. Examples of the FlIMA silica-based powder include Aeroseal (manufactured by Nippon Aeroseal Co., Ltd., trade name), and preferably has a particle size of 1 μm or less.

The (C)# acid ester solvent used in the present invention is used as a component of the paste solvent, and there are no particular restrictions on the type of ester component.

Examples of these solvents include methyl acetate, ethyl acetate,
Examples include butyl acetate, isopropyl acetate, amyl acetate, and the like, and these may be used alone or in a mixture of two or more.

The conductive paste used in the present invention contains a modified resin made of polyparahydroxystyrene resin and epoxy resin, a conductive powder, a fine silica powder, and an acetate-based melt as essential components, but this is contrary to the purpose of the present invention. Antifoaming agents and other additives may be added and blended as required. After thoroughly mixing these components according to a conventional method, the mixture is further kneaded using, for example, three rolls, and then defoamed under reduced pressure and diluted with an acetate ester-based diaphragm.

(Function) The conductive paste of the present invention can improve adhesiveness and bleeding resistance, especially by using a modified resin consisting of polyparahydroxystyrene resin and epoxy resin.

(Examples) Next, the present invention will be specifically explained by examples, but the present invention is not limited by these examples.
In the following Examples and Comparative Examples, "1 part" means "part by weight" unless otherwise specified.

Example 1 37.5 parts of epoxy resin Epicoat Toot (manufactured by Shell Chemical Co., Ltd., trade name) and 10 parts of polyparahydroxystyrene resin Marcarin Power-M (manufactured by Marukubi Petrochemical Co., Ltd., trade name) were mixed with diethylene glycol diethyl A dissolution reaction was carried out in 103 parts of ether at 100° C. for 1 hour to obtain a viscous resin. To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst, 0.03 parts of additives, 57 parts of silver powder, 20 parts of Aeroseal #200 (manufactured by Nippon Aeroseal Co., Ltd., trade name), and A conductive paste was prepared by mixing 50 parts of butyl acetate.

Example 2 15.8 parts of epoxy resin Epikote 828 (manufactured by Shell Chemical Co., Ltd., trade name) and 1 part of polyparahydroxystyrene resin Marcarin Power-M (manufactured by Marukubi Petrochemical Co., Ltd., trade name)
0 parts and 10 parts in 56 parts of butyl cellosolve acetate.
A dissolution reaction was carried out at 0° C. for 1 hour to obtain a viscous resin. To 22 parts of this resin, 1.0 part of boron trifluoride amine complex as a catalyst, 57 parts of silver powder, Aeroseal #200 (
A conductive paste was prepared by mixing 2.5 parts of the above) and 50 parts of butyl acetate.

Example 3 66 parts of epoxy resin EOCN103S (manufactured by Nippon Kayaku Co., Ltd., trade name) and 34 parts of polyparahydroxystyrene resin Marcarin Power-M (described above) were heated at 100°C in 117 parts of butyl carpitol acetate. After a time dissolution reaction, a viscous resin was obtained. To 22 parts of this resin, 1.0 part of an amine complex of boron trifluoride as a catalyst, and 57 parts of silver powder.
2.0 parts of Aerosil #200 (mentioned above), and 50 parts of butyl acetate were mixed to prepare a conductive paste.

Comparative Example A commercially available epoxy resin-based melt-cutting conductive paste for semiconductors was obtained.

The conductive pastes obtained in Examples 1 to 3 and Comparative Examples were subjected to adhesion, bleed tests, and accelerated microscopy tests. The results are shown in Table 1. In all cases, the present invention was superior, and the effects of the present invention were recognized.

In addition, the adhesive strength test was conducted on a lead frame made of pure silver plating. Ox2. Onn silicon chips were bonded and measured using a tension gauge at a temperature of 25°C.

In the bleed test, conductive paste was screen printed on a slide glass plate, and a 2atl pressure test (PC"rl) was performed for 24 hours, and then the state of bleed at the glass interface was evaluated. Accelerated migration test As shown in Fig. 1, S# conductive paste was screen printed on a slide glass plate with a width of 5n+n and a thickness of 20μm, with a discontinuous part 3 of @2II11 in the middle. Distilled water 4 was dropped onto the 2 mm discontinuous portion 3, a DC voltage of 8 V was applied, and the time difference until current leakage was measured.

Table 1 (Units) Excellent reading properties, no oozing of conductive powder, and good migration resistance. Therefore, by using this conductive paste, highly reliable electronic components can be manufactured.

[Brief explanation of the drawing]

Figure 1 is for explaining the accelerated migration test method! FIG. 3 is a plan view of a test piece with poles. DESCRIPTION OF SYMBOLS 1... Slide glass plate, 2... Conductive paste, 3... Discontinuous part, 4... Distilled water. *1: O mark - some bleed, × mark - a lot of bleed. [Effects of the invention J

Claims (1)

[Claims] 1. (A) A modified resin consisting of a polyparahydroxystyrene resin and an epoxy resin (B) A conductive powder and a fine silica powder (C) An acetate ester solvent is an essential component. conductive paste.