JPS6121172A - Heat-resistant and electroconductive adhesive - Google Patents

Abstract

PURPOSE:The title adhesive that contains, as major components, a specific polyparabanic acid resin, an electroconductive powder, and a solvent, thus being suitable for adhesion of IC chips, because of its high heat resistance, adhesion and electroconductivity. CONSTITUTION:The objective adhesive is obtained by using (A) a polyparabanic acid resin of the formula (X is CH2, O, SO2; n is positive integer), (B) an electroconductive dust such as of copper, silver or zinc and (C) a solvent such as dimethylformamide or dimethylacetamide. The amount of component B used is 100pts.wt., component A is 15-50pts.wt. and C is 0.1-50pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a heat-resistant and conductive adhesive that has excellent heat resistance, adhesion and conductivity, and is particularly suitable for bonding IC chips.

[Technical bronze of the invention and its problems] Conductive adhesives are widely used to connect and cover chips of RC, LSI, etc. with electrodes of insulating substrates, lead frames, etc.

However, conventional conductive adhesives cannot be heated during baking.
Otherwise, it may change in quality due to heating during bonding with gold wires, or even conductive adhesives made of epoxy resin can cause various troubles and become major problems in the case of semiconductor devices that are sealed at extremely high temperatures, such as glass. It has become. Therefore R31
i, a heat-resistant conductive adhesive containing polyimide resin as the main component, has been developed.However, polyimide resin, which undergoes a dehydration and cyclization reaction during curing, generates voids due to dehydration and has problems with the adhered object. The adhesion 1'l between objects may become poor or undesirable. Other combinations of various inorganic or organic adhesives and conductive powders have been tested, but none have been obtained so far, and there is a demand for the development of a heat-resistant and conductive adhesive. ing.

[Object 1 of the Invention] The present invention has been made in view of the above two problems, and is a heat-resistant and conductive film with excellent heat resistance, adhesiveness, and conductivity. [Intended to provide adhesives.]

[Summary of the Invention] As a result of intensive research to achieve the above object, the present invention has been made based on a polyparabanic acid resin that already has an integrated cyclized structure and has excellent solubility in solvents.
It has been found that the objects of the invention are achieved.

That is, the present invention (A>General formula (However, in the formula, X is -CI-12-, -〇-.

-5O2- and n is a positive integer), a heat-resistant and conductive adhesive characterized by containing as main components a polyparabanic acid resin, (B) a conductive powder, and (C) a solvent. It is.

Unlike conventional polyimide resins, the polyparabanic acid resin (A) used in the present invention has a five-membered Peter ring structure, although it is soluble in a solvent.
Conventional polyimide resins do not dissolve in solvents once an imide structure is formed, so they are dissolved in a solvent in the form of polyamic acid resin, which is a precursor polymer, and then dehydrated and cyclized by heat curing at 250°C or higher. A method of forming an imide is used. Since polyparabanic acid does not require dehydration and cyclization, no voids are created between the adhesive and the adhered material due to dehydration, so it can exhibit good adhesion, and it can also be heat-treated at temperatures below 200°C. Often extremely efficient.

The conductive powder (I3) used in the present invention includes copper, silver,
Examples include tin, lead, nickel, etc., and these may be used alone or as a mixture of two or more.

Considering the conductivity of the conductive powder, it is suitable to use silver, but in consideration of long-term conductivity deterioration, cost, etc., powders other than silver are appropriately mixed and used.

The shape of the powder is not particularly limited, and flake or spherical shapes are effectively used. Also, synthetic resins and other powders having these metal layers on their surfaces can also be used.

Examples of the solvent (C) used in the present invention include dimethylacetamide, dimethylformamide, N-methyl-2-
Examples include pyrrolidone and cresol, which may be used alone or as a mixture of two or more.

Next, the blending ratio of the present invention will be explained.

51 The heat-resistant and conductive adhesive of the present invention comprises polyparabanic acid resin,
The main components are conductive powder and a solvent, and the mixing ratio of these is in the range of 15 to 50 parts by weight of polyparabanic acid resin and 0.1 to 50 parts by weight of solvent per 100 parts by weight of conductive powder. It is preferable.

If the amount of the polyparabanic acid resin (1) is less than 15 parts by weight, it has no effect on heat resistance and adhesiveness, and if it exceeds 50 parts by weight, the conductivity deteriorates, which is not preferable. If the amount of the solvent is less than 0.1 parts by weight, it has no effect on adhesive properties, and if it exceeds 50 parts by weight, heat resistance deteriorates, which is not preferable. Therefore, it is better to limit it within the above range.

The heat-resistant and conductive adhesive of the present invention includes polyparabanic acid resin,
Although the main ingredients are conductive powder and a solvent, other ingredients such as colorants, curing agents,
Additives such as curing accelerators can be added. The adhesive of the present invention can be manufactured by adding the above-mentioned main components and each additional component and thoroughly mixing and kneading them using a triple roll or the like.

The heat-resistant and conductive adhesive of the present invention has excellent coating performance,
15Fl can be applied to insulators and lead frames by screen printing, dispenser application, etc. Although it is possible to fire with a variety of firing methods,
Preferably, the temperature is 180-200°C for 30-60 minutes. Since the heat resistance of the polyparabanic acid IH resin after firing is extremely excellent, the protective layer can sufficiently withstand heating at 350° C. for 10 minutes.

This shows that it can sufficiently withstand the effects of bonding gold wire to chips such as IC1L S I. This adhesive adheres well to ceramic, synthetic resin, glass, and other substrates, and also exhibits excellent adhesive strength to silver, palladium, platinum, gold, and copper electrodes.

[Examples of the Invention] Next, the present invention will be described with reference to Examples. The present invention is not limited to these examples.

Examples 1 to 3 The compositions shown in Table 1 were sufficiently pre-kneaded and then passed through three times using a ceramic triple roll to produce heat-resistant and conductive adhesives.

Comparative Examples 1-2 Conductive adhesives were manufactured by mixing and kneading the compositions shown in Table 1 in the same manner as in the examples.

The conductive adhesive produced in Examples 1 to 3 and Comparative Examples 1 to 2 was applied to a silver electrode provided on an insulating substrate using a dispenser method, and a 1 mm square IC chip was further layered on the side on this adhesive. , and baked at 200°C for 30 minutes. Thereafter, a characteristic test of the conductive adhesive was conducted, and the results are shown in Table 1. "Strength" in Table 1 is calculated after placing the IC chip on a conductive adhesive and baking it at 200°C for 30 minutes, or after baking it under the above conditions and then heating it at 350°C for 10 minutes.
The strength after heat treatment (same as the heat treatment conditions for bonding the gold wire to the C chip) is shown. Strength indicates the adhesion between the boundary layer of the IC chip and the conductive adhesive, and is expressed as the shear strength when the side surface of the IC chip is pressed horizontally with a push gauge.

As is clear from Table 1, the conductive adhesive of the present invention has 2
Excellent strength was exhibited even after firing at 00°C and after treatment at 350°C for 10 minutes, demonstrating the remarkable effects of the present invention.

[Effects of the Invention] The adhesive of the present invention has excellent heat resistance, adhesiveness, and conductivity, and is particularly suitable as a conductive adhesive for chips such as ICs. By using this adhesive, it is possible to obtain excellent electronic components or circuits without deterioration of the adhesive or voids.

Claims (1)

[Claims] 1 (A) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, X is -CH_2-, -O-, -SO_2-
, n is a positive integer, respectively); (B) conductive powder; and (C) solvent. 2 The blending amount of polyparabanic acid resin is 100% of the conductive powder.
15-50 parts by weight of the heat-resistant powder according to claim 1, wherein the amount of the solvent is 0.1-50 parts by weight based on 100 parts by weight of the conductive powder.・
conductive adhesive.