JP2002128866A - Conductive paste - Google Patents

Abstract

(57) [Problem] To provide a conductive paste which can contribute to improvement in reliability of a semiconductor device, has high adhesive strength, and has a small increase in viscosity due to a reaction at 25 ° C. or lower. SOLUTION: A reactive diluent such as (A) epoxy resin, (B) polypropylene glycol glycidyl ether,
(C) a liquid alkyl aromatic diamine of (1) or (2) represented by the following formula: (D) A conductive paste comprising imidazoles as a catalyst and (E) a conductive powder as essential components.

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 a small viscosity increase and a high adhesive strength, which is used for chip mounting and bonding of various electronic parts in assembling a semiconductor device.

[0002]

2. Description of the Related Art In the assembly of a semiconductor device, a process of mounting a semiconductor chip such as an IC or an LSI on a predetermined portion on a metal thin plate (lead frame) or a resin substrate includes the following steps.
This is one of the important steps affecting the long-term reliability of the device. Conventionally, as the mounting method, there are a method of brazing using an alloy (solder) having a low melting point, a method of using a resin paste mainly composed of an epoxy resin, and the like.

[0003]

However, although some of the methods using solder have been put to practical use, there is a possibility that solder or solder balls may scatter and adhere to electrodes and the like, which may cause corrosion and disconnection. It is pointed out.

Further, when a conventional liquid diamine is used as a curing agent in a method using a resin paste, the thickening rate due to the reaction of the resin composition is large even at room temperature of 25 ° C. or less, and therefore the pot life is long. Shorter and problematic.

An object of the present invention has been made in view of the above circumstances, and has a high adhesive strength and a small conductivity increase at a reaction temperature of 25 ° C. so as to contribute to the improvement of the reliability of a semiconductor device. It is intended to provide a paste.

[0006]

Means for Solving the Problems As a result of diligent research aimed at achieving the above object, the present inventor has found that by using a resin composition having the composition described below, it is particularly possible to obtain a predetermined compounding amount. It has been found that the above object can be preferably achieved, and the present invention has been completed.

That is, the present invention provides (A) an epoxy resin,
(B) a reactive diluent, (C) a liquid alkyl aromatic diamine of (1) or (2) shown in the following formula,

Embedded image (D) A conductive paste comprising an imidazole as a catalyst and (E) a conductive powder as essential components.

Hereinafter, the present invention will be described in detail.

The epoxy resin (A) used in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule. Specifically, for example, bisphenol A glycidyl ether type epoxy resin , Bisphenol F glycidyl ether type epoxy resin, phenol novolak type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin and the like.

As the reactive diluent (B) used in the present invention, n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butyl Phenyl glycidyl ether, glycidyl methacrylate, t-
Butylphenyl glycidyl ether, diglycidyl ether, (poly) ethylene glycol diglycidyl ether, (poly) propylene glycol diglycidyl ether, butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 1,6-hexanediol diglycidyl ether, etc. These can be used alone or in combination of two or more.

The mixing ratio A / B (weight ratio) of (A) the epoxy resin and (B) the reactive diluent is 90/10 to 50/5.
It is appropriate to set the range to 0.

The liquid alkyl aromatic diamine (C) used in the present invention is used as a curing agent, and is not particularly limited as long as it has a structure represented by any of the above formulas (2). Specifically, for example, Kayahard A-A
(Manufactured by Nippon Kayaku Co., Ltd., trade name) and the like.

The imidazole as the catalyst (D) used in the present invention is not particularly limited as long as it is an imidazole compound. Specifically, for example, 2MZ, 1B
2MZ, 2E4MZ, 2E4MZ-CN, 2MZ-AZ
INE, 2MZ-OK (Shikoku Chemical Industry Co., Ltd., trade name) and the like, and these can be used alone or in combination of two or more.

As the (E) conductive powder used in the present invention, for example, metal powders such as silver powder, copper powder and nickel powder, carbon and the like can be suitably used, and these can be used alone or as a mixture of two or more kinds. Can be used.
Further, as long as the powder has conductivity, the powder is not limited to the metal powder. For example, an insulating powder having a metal layer only on the surface may be used. The shape of the conductive powder is not particularly limited.
It is preferable that the thickness be not more than μm. Particle size of conductive powder is 5
If it exceeds 0 μm, conductivity becomes unstable. Here, the particle size is defined as the diameter of a sphere having the same volume.

When the total amount of the resin component (A) and the conductive powder (E) in the conductive paste is 100 parts by weight, the mixing ratio of the conductive powder is (A) / (E) = 40/60.
It is desirable to set the range to 5/95 (parts by weight).
When the proportion of the conductive powder of (E) is less than 60 parts by weight, it is difficult to obtain sufficient conductivity, and when it exceeds 95 parts by weight, the workability and the adhesion are reduced, so that it is preferable. Absent.

Further, in the present invention, for example, a solvent for adjusting the viscosity of the conductive paste, an antifoaming agent, a coupling agent and other various additives can be blended as required.

Examples of the solvent include cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, diethylene glycol dimethyl ether, diacetone alcohol, N-
Examples thereof include methylpyrrolidone, dimethylformamide, γ-butyllactone, 1,3-dimethyl-2-imidazolididone, and the like, and these can be used alone or in combination of two or more.

Further, examples of the coupling agent include γ-glycidoxypropyltrimethoxysilane and γ
-Methacryloxypropyltrimethoxysilane and the like.

The conductive paste of the present invention can be easily prepared by sufficiently mixing the above essential components and optional components, further kneading with a disperse, kneader or a three-roll mill, and then defoaming under reduced pressure. You can get it. The conductive paste thus obtained can be suitably used for manufacturing semiconductor devices and bonding various electronic components. For example, when used in the manufacture of a semiconductor device, a conductive paste is filled into a syringe or the like, and then discharged onto a thin metal plate or a resin substrate using a dispenser. The paste is mounted on a substrate and cured by heating. In addition,
In curing the conductive paste of the present invention, it is usually carried out by heating at 100 ° C. to 150 ° C. for 1 hour to 3 hours.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 YL983 as a bisphenol F glycidyl ether
U (manufactured by Yuka Shell Epoxy, trade name) 80 parts, polypropylene glycol glycidyl ether 20 parts as a reactive diluent, Kayahard A-A (liquid trade name, trade name) 25 parts as a liquid alkyl aromatic diamine, 4 parts of 2MZ-OK (Shikoku Chemical Industry Co., Ltd., trade name) as imidazole, flaky silver powder (average particle size: 20 μm) 675
Parts, and 100 parts of butyl cellosolve acetate as a diluent, were sufficiently mixed, and then kneaded with three rolls to obtain a conductive paste.

Examples 2 to 4 Conductive pastes were obtained in the same manner as in Example 1 at the composition ratios shown in Table 1.

Comparative Example 1 YL983 as a bisphenol F glycidyl ether
U (manufactured by Yuka Shell Epoxy Co., Ltd., trade name) 80 parts, polypropylene glycol glycidyl ether 20 parts as a reactive diluent, liquid heterocyclic diamine 25 parts shown in the following formula 3 as a liquid diamine,

Embedded image 4 parts of 2MZ-OK (Shikoku Chemical Industry Co., Ltd., trade name) as imidazole, flaky silver powder (average particle size 20 μm)
675 parts, butyl cellosolve acetate 1 as a diluent
After thoroughly mixing 00 parts, the mixture was further kneaded with three rolls to obtain a conductive paste.

Comparative Examples 2 to 4 Conductive pastes were obtained in the same manner as in Comparative Example 1 at the composition ratios shown in Table 2.

The liquid diamine polyoxypropyleneamine used in Comparative Examples 2 and 4 has the structural formula shown in the following chemical formula 4.

[0026]

Embedded image The thickening rates were measured using the conductive pastes obtained in Examples 1 to 4 and Comparative Examples 1 to 4, and the results are shown in Tables 1 and 2.

The viscosity was measured using an EHD viscometer.
° 34 'cone, 0.5 prm, sample amount 2 g, temperature 25
This was carried out under the condition of ° C. Then, the rate of increase in the viscosity at 25 ° C. was determined by storing the sample whose initial viscosity was measured at 25 ° C. for 24 hours.
The viscosity after time was measured, and the percentage of viscosity / initial viscosity after 24 hours was determined. When the viscosity could not be measured after 24 hours, the time (minutes) at which the sample stored at 25 ° C. had a viscosity twice as high as the initial viscosity was determined, and this was defined as the viscosity doubling time at 25 ° C.

As shown in Tables 1 and 2, in Comparative Examples, the rate of thickening at 25 ° C. was large, and it was impossible to measure the rate of increase in viscosity at 25 ° C. From these results, a remarkable effect of the present invention was confirmed.

[0029]

[Table 1]

[Table 2]

[0030]

As is clear from the above description and Tables 1 and 2, according to the conductive paste of the present invention, compared with the conventional conductive paste using a liquid diamine as a curing agent, 25%.
It is possible to provide a conductive paste having a small increase in viscosity at a temperature of ° C. Furthermore, according to the conductive paste of the present invention,
Because of the above-described characteristics, for example, it is applicable to the manufacture of a semiconductor device, and a highly reliable semiconductor device can be manufactured.

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Claims (1)

[Claims] 1. An epoxy resin, (B) a reactive diluent, (C) a liquid alkyl aromatic diamine of (1) or (2) represented by the following formula: (D) A conductive paste comprising an imidazole as a catalyst and (E) a conductive powder as essential components.