JPH01110582A - Heat-resistant adhesive - Google Patents

Abstract

PURPOSE:To obtain the above adhesive, consisting essentially of a polyimide based resin, flaky solder powder and organic solvent, useful for semiconductors, quartz oscillators, etc., and having excellent heat resistance without causing voids or cracks. CONSTITUTION:The aimed adhesive consisting essentially of (A) a polyimide based resin (e.g., polyimide resin which is a polycondensation or addition reaction type resin having imide bonds in the backbone chain of the polymer), (B) flaky solder powder (e.g., Sn-Pb based solder containing <=2% impurity) and (C) an organic solvent (e.g., DMF or N-methyl-2-pyrrolidone). Furthermore, the blending ratio based on 100pts.wt. component (B) is preferably 15-50pts.wt. component (A) and 50-200pts.wt. component (C).

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention has excellent heat resistance and is used for bonding semiconductors, crystal oscillators, etc. Concerning heat-resistant adhesives that do not cause voids or cracks.

(Prior Art) Generally, packaging methods such as resin sealing, glass sealing, and Ag brazing are used for semiconductors and crystal oscillators. The adhesion of the substrate of the element in paragauging is also selected according to this paragauge method, and for resin sealing with a relatively low sealing temperature, glyform, solder, organic adhesive,
Preforms have been commonly used for higher temperature glass sealing, and preforms for Ag brazing. Among these methods, methods using organic adhesives have good productivity and have been rapidly growing in recent years. On the other hand, when an organic adhesive is used for glass sealing, the sealing temperature is as high as 400 to 450°C, so it is known that ordinary resins will thermally decompose and lose their adhesive strength. For this reason, it is common practice to use polyimide resins with high heat resistance. Polyimide resin with silica powder, silver powder, etc. added as a filler is used. Adhesives mixed with silica powder have good heat resistance, but have the disadvantage that voids and cracks occur in the bonding material, making them impractical.

Furthermore, those containing silver powder significantly impaired the good heat resistance of the polyimide resin, and the decomposition temperature was 400° C. or lower, making it unusable. When aluminum powder or copper powder other than silver powder is used, there is a drawback that the pot life of the adhesive is significantly deteriorated.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances. The purpose of the present invention is to provide a heat-resistant adhesive that is free from voids and cracks and capable of sealing glass at a thermal decomposition temperature of 400° C. or higher.

[Structure of the Invention] (Means for Solving the Problems) As a result of intensive research to achieve the above object, the inventor of the present invention has achieved the following by using solder powder, especially in the form of flakes, as a filler. The present invention was completed based on the discovery that voids and cracks do not occur, the heat resistance of polyimide resin can be maintained, and high-temperature glass sealing is possible.

That is, the present invention is a heat-resistant adhesive containing a polyimide resin, flaky solder powder, and an organic solvent as essential components.

Polyimide resins used in the present invention include polyimide resins with imide bonds in the main chain of the polymer, polyimide resins with polycondensation molds, addition reaction type polyimide resins, and polyimide resins with amide bonds or ester bonds introduced into the main chain. Examples include polyamide-imide resins, polyesterimide resins, polyimide resins with triazine rings introduced, and modified resins thereof, and these may be used alone or in a mixture of 2'vA or more.

The flaky solder powder used in the present invention includes 5n-P
Impurities of 2% or less (sb, cu.

It may contain Bi, Zn, Fe, AI, As, etc.), and may be used in a wide range of ways without any particular limitations, other than being in the form of flakes.

Examples of the organic solvent used in the present invention include dimethylpolamide, dimethylacetamide, n-methyl-2-
Examples include pyrrolidone and dioxane, which may be used alone or as a mixture of two or more.

The heat-resistant adhesive of the present invention has each of the above-mentioned components as essential components, and the proportions of each component are as follows. It is desirable to mix 15 to 50 parts by weight of polyimide resin with 100 parts by weight of flaky solder powder. If the amount of polyimide resin blended is less than 15 parts by weight, it will become lumpy and will not form a paste, and if it exceeds 50 parts by weight, the viscosity will be low and the adhesive will have poor coating properties, making it impractical.
The blending ratio of the organic solvent is preferably 50 to 200 parts by weight per 100 parts by weight of flaky solder powder.

If the blending amount is less than 50 parts by weight or exceeds 200 parts by weight, a situation similar to that of polyimide resin will occur, which is not preferable.

The heat-resistant adhesive of the present invention includes a polyimide resin, flaky solder powder, and a solvent as essential components, but other components may be added as long as the object of the present invention is not impaired. By mixing and stirring the components selected in this manner, a heat-resistant adhesive can be easily produced.

This heat-resistant adhesive can be applied to various insulating substrates and electrodes by screen printing or brush painting, which has excellent application performance. Further, the heat-resistant adhesive can be fired under various self-forming conditions, but for example, firing at 300°C for about 60 minutes is sufficient. The heat resistance after firing is extremely excellent, and it can withstand heating at 450° C. for 30 minutes, indicating that it can withstand the paragassing process for glass sealing.

The heat-resistant adhesive of the present invention adheres well to any substrate commonly used as an adhesive substrate, and exhibits good adhesion to ceramics, synthetic resins, glass, etc. Adhesion strength to electrodes is also very large and excellent.

(Function) The heat-resistant adhesive of the present invention exhibits good adhesive strength even at temperatures above 400°C without decomposing the polyimide resin due to the use of flaky wood powder. Polyimide adhesives have a low decomposition temperature, and cracks occur with polyimide adhesives that use silica powder, while epoxy adhesives have a low thermal decomposition temperature.
While none of them could withstand the glass-sealed paragauge using a large pellet, the heat-resistant adhesive of the present invention clearly showed a significant difference.

(Example) Next, the present invention will be explained in detail. In the following examples and comparative examples, "parts" means "parts by weight."

Example 1 A heat-resistant adhesive was produced by thoroughly kneading 2 parts of an addition reaction type polyimide resin, 5 parts of flaky solder powder, and 8 parts of N-methyl-2-pyrrolidone.

Examples 2 to 3 Heat-resistant adhesives were produced in the same manner as in Example 1 using the compositions shown in Table 1.

Comparative Examples 1 to 3 Heat-resistant adhesives were produced in the same manner as in Example 1 using the compositions shown in Table 1.

The heat-resistant adhesive obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was applied to a silver-palladium electrode provided on an insulating substrate by a dispenser method, and an IC chip was further attached to the adhesive. Baking at 300°C for 60 minutes (comparative example 3 was fired at 200°C)
The results are shown in Table 1. The results are shown in Table 1.

*1: Place the IC chip of G + mouth 10 into L with adhesive 30
After firing at 0°C for 60 minutes, check for occurrence of voids and cracks.

×, Δ, and O indicate good results in that order.

*2: Place a 6n1 IC chip on the adhesive and
It represents the adhesion between the boundary layer between the IC chip and the adhesive after baking at ℃ for 60 minutes, and the breaking strength was measured by pressing a push-pull gauge against the side of the chip.

*3: The cured adhesive was measured at 10°C/+ using a thermogravimetric analyzer.
The decomposition start temperature was measured when the temperature was raised (in air) at a speed of 100 min.

[Effects of the Invention] As is clear from the above explanation and Table 1, the heat-resistant adhesive of the present invention has excellent heat resistance, does not generate voids or cracks, and has a thermal decomposition temperature of 450°C or higher. This makes it suitable for use in glass-sealed packages.

Claims (1)

[Claims] 1. A heat-resistant adhesive containing polyimide resin, flaky solder powder, and an organic solvent as essential components.