JPH0439809A - 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, and using an epoxy resin incorporating a thermal resistant benzophenone imide group as a part of the epoxy resin. CONSTITUTION:Conductive paste essentially includes a denatured resin A consisting of a polypallahydroxy stylene resin and an epoxy resin, an epoxy resin B having a benzophenone imide group, conductive powder and fine silica powder C and an acetate solvent D. 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 epoxy resin B, an epoxy resin incorporating an epoxy group and a benzophenone imide group in a compound is used. As the conductive powder and fine silica powder C, conductive powder and fine silica powder are used together. Therefore, it is possible to improve adhesiveness, bleeding resistance and migration resistance.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention provides a conductive paste that has excellent adhesiveness and bleeding resistance and is used for the assembly of electronic parts, etc. Regarding.

(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.

(Problem 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 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. This is an attempt to develop a conductive base.

[Structure J of the Invention (Means for Solving the Problems) As a result of intensive research aimed at achieving the above object, the present inventors have found that adhesive properties and bleeding resistance have been improved by using the composition described below. It was discovered that a conductive paste with excellent properties could be obtained, and the present invention was completed.

That is, the present invention comprises (A) a modified resin consisting of a polyparahydroxystyrene resin and an epoxy resin, (B) an epoxy resin having a benzophenone imide group, (C) a conductive powder and a fine silica powder, and (D) This conductive base is characterized by containing an acetate-based solvent as an essential component.

The present invention will be explained in detail below.

The modified resin used in the present invention (A> consisting of a polyparahydroxystyrene resin and an epoxy resin) 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. Additionally, a curing catalyst can 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 Marukalinyoku-M (manufactured by Marukubi Petrochemical Co., Ltd., trade name), which has a molecular weight of 3000 to 800.
0 and the hydroxyl equivalent is about 120. In addition, as epoxy resins used for modified resins, the following bisphenol dieboxides are industrially produced and can be effectively used in the present invention.6 Epicote 827, 828, 834, 1001, 1002゜1007.1009 <Manufactured by Shell Chemical Co., Ltd., trade name), D
ER330, 331, 332, 334, 335°336
．． 337.660 (product name manufactured by Dow Chemical Company), Araldite GY250, 260, 280°6071.60
84,6097.6099 (manufactured by Ciba Geigy, product name), EPI-REZ510°5101 (JONE
DABNEYl [, trade name), Ebikuron 810,10
00,1010°3010<manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name), and BP 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 temperatures (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 EPNI 138.11
39, ECN12731280.1299 <manufactured by Ciba Geigy, trade name), DEN431,438 (manufactured by Dow Chemical Company, trade name), Epicote 152,154 (manufactured by Shell Chemical Company, trade name), ERR-0100, ERRB
0447, ERLB-0488 (manufactured by Union Carbide Co., Ltd., trade name), EOCN series (manufactured by Nippon Kayaku Co., Ltd., trade name), etc. These epoxy resins can be used alone or in a mixture of two or more. .

It is desirable to dissolve and mix the modified resin consisting of polyparahydroxystyrene resin and epoxy resin in the following solvents. Solvents that can be used here include dioxane, hexane, benzene, toluene, solvent naphtha, industrial kanrin, and cellosolve acetate. , ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carpitol acetate, diethylene glycol diethyl ether, dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, etc., and these may be used alone or in combination of two or more.

The epoxy resin (B) having a benzophenone imide group used in the present invention may be one having both an epoxy group and a benzophenone imide group in the compound, and examples thereof include those having the following structure.

The blending ratio of the epoxy resin having benzophenone imide groups is 11 [(A) + (B)] in total of the resin components.
It is desirable that the content be 5 to 80% by weight.

If the blending amount is 5% by weight, it is not effective in improving adhesive strength, and if it exceeds 80% by weight, the reactivity tends to be poor, which is not preferable.

As the conductive powder and fine silica-based powder (C) 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 fine silica-based powders include Aeroseal (trade name, manufactured by Nippon Aeroseal Co., Ltd.), and those having a particle size of 1 μm or less are preferable.

The <D) acetate ester solvent used in the present invention is not particularly limited by the content of the ester component.
These are used as a component of the solvent of conductive paste, such as methyl acetate, ethyl acetate, butyl acetate, isopropyl acetate, amyl acetate, etc. These can be used alone or in a mixture of two or more. .

The conductive paste used in the present invention contains as essential components a modified resin consisting of a polyparahydroxystyrene resin and an epoxy resin, an epoxy resin containing a benzophenone imide group, a conductive powder, a WIIt41I silica powder, and an acetate bath agent. However, within the scope of the purpose of the present invention and as necessary, antifoaming agents and other additives may be added and blended.9 After thoroughly mixing these components in accordance with a conventional method, further e.g. It can be produced by kneading with three rolls, followed by defoaming under reduced pressure and diluting with an acetate solvent.

(Function) The conductive paste of the present invention is produced by using a modified resin consisting of a polyparahydroxystyrene resin and an epoxy resin, and by using an epoxy resin having a heat-resistant benzophenone imide group as a part of the epoxy resin. , adhesion and bleeding resistance can be improved.

(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, [Part J means "parts by weight" unless otherwise specified.

Example 1 Epoxy resin Epicoat 1001 (manufactured by Shell Chemical Co., Ltd.)
(Product name) 33.7 parts and Marukaline power of polyparahydroxystyrene resin-M (manufactured by Marukubi Petrochemical Co., Ltd., trade name) 1
0 part and 3.75 parts of an epoxy group having a benzophenone imide group were dissolved and reacted in 103 parts of diethylene glycol diethyl ether at 100° C. for 1 hour to obtain a viscous tM fat. 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, and 2.0 parts of Aeroseal #200 (trade name, manufactured by Nippon Aeroseal Co., Ltd.) , and 50 parts of butyl acetate to prepare a conductive paste.

Example 2 14.3 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 part and 1.58 parts of an epoxy resin having a benzophenone imide group were dissolved and reacted in 56 parts of butyl cellosolve acetate at 100°C for 1 hour to obtain a viscous resin. To 22 parts of this resin, boron trifluoride amine fl#1 was added as a catalyst. A conductive paste was prepared by mixing O parts, 57 parts of silver powder, 2.5 parts of Aeroseal #200 (described above), and 5 o parts of butyl acetate.

Example 3 60 parts of epoxy resin EOCN103S (manufactured by Nippon Kayaku Co., Ltd., trade name), 34 parts of polyparahydroxystyrene resin Marcarin Power-M (described above), and 6.6 parts of an epoxy resin having a benzophenone imide group. were dissolved and reacted in 117 parts of butylcarpitol acetate at 100°C for 1 hour to obtain a viscous resin. To 22 parts of this resin,
As a catalyst, 1.0 part of an amine complex of boron trifluoride, 57 parts of silver powder, 2.0 parts of Aerosil #200 (mentioned above),
and 50 parts of butyl acetate to prepare a conductive paste.

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

Adhesion, bleed tests, and accelerated migration tests were conducted on the conductive pastes obtained in Examples 1 to 3 and Comparative Examples. The results are shown in Table 1, and the present invention was superior in all cases, and the effects of the present invention were recognized.

In addition, the adhesive strength test was performed by adhering a 2.0 x 2.0 nn silicon chip to a silver-plated lead frame and measuring it at a temperature of 25° C. using a tension gauge. In the bleed test, the conductive paste was screen printed on a slide glass plate, and a 2 atm pressure test (PCT) was performed for 24 hours, and then the state of bleed at the glass interface was evaluated. In the accelerated migration test, as shown in Fig. 1, conductive paste 2 was placed on a slide glass plate with a width of 51 m and a thickness of 2.
Screen print to create a discontinuous part 3 of 421n in the middle with 0 μl, drop distilled water 4 on the discontinuous part 3 of @2111, apply a DC voltage of 8 V, and measure the time until the current leaks. did.

Table 1 (unit) FIG. 2 is a plan view of a test piece with electrodes for clarification.

■...Slide glass plate, 2...Conductive paste, 3...Fi! Pillow part, 4... Distilled water.

Patent Applicant: Toshiba Chemical Corporation [Effects of the Invention J As is clear from the above explanation and the results in Table 1, the conductive paste of the present invention has excellent adhesion and bleeding resistance, and has excellent adhesion and bleeding resistance. Good migration resistance with no leakage. Therefore, by using this conductive paste, highly reliable electronic components can be manufactured.

[Brief explanation of drawings]

Claims (1)

[Scope of Claims] 1 (A) a modified resin consisting of a polyparahydroxystyrene resin and an epoxy resin, (B) an epoxy resin having a benzophenone imide group, (C) a conductive powder and a fine silica powder, and (D ) A conductive paste characterized by containing an acetate ester solvent as an essential component.