JPS60229945A - Epoxy resin sealing material - Google Patents

Abstract

PURPOSE:To obtain the titled material having improved adhesivity between the filler and the resin, high moisture resistance, and remarkably improved corrosion resistance, and suitable for the sealing of a semiconductor device such as IC, by compounding an epoxy resin with an organic filler coated with an organopolysilsesquioxane. CONSTITUTION:An inorganic filler (e.g. crystalline silica powder, quartz glass powder, etc.) is immersed and mixed in a silicon resin solution having a concentration of 1-50wt% and composed of an organopolysilsesquioxane of formula (R1 and R2 are methyl, phenyl, etc.) and an organic solvent (e.g. benzene, toluene, etc.), and the mixture is filtered and dried. The product is compounded in an epoxy resin at a ratio of 60-70wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the construction of an epoxy encapsulant material with improved moisture resistance.

Since electronic components are significantly affected by humidity, various moisture-proof exteriors are applied to them depending on their guaranteed reliability.

Therefore, for parts that require high reliability, hermetically sealed exteriors that use a metal case and glass terminals, or hermetically sealed exteriors that seal a porcelain case with a eutectic solder, have been used.

On the other hand, resin molded exteriors also exist, but due to their poor moisture resistance, their use has been limited to radio and television parts, and has not been used for parts that require high reliability.

However, the element itself enclosed in the case must be made immobile (
As a result of progress in moisture-proofing treatments such as puffing and other improvements in sealing resins, the reliability of resin molds has improved, and resin mold exteriors have come to be used in a wide range of fields.

Particularly in semiconductor devices where mass production is progressing and cost reduction is required, there is a need to develop resin encapsulating materials with improved moisture resistance.

(, b) Conventional technology When packaging electronic components, particularly semiconductor elements such as ICs and LSIs, with resin, the following requirements are: 1. The shrinkage rate during molding must be small and the adhesiveness with the lead frame must be good.

2. Contains few impurities that conduct ions.

3. Good fluidity during molding, without deforming or damaging the bonding wire.

4. Good thermal conductivity.

5. Short molding time and good mold releasability.

etc. can be mentioned.

It is necessary for the sealing resin to satisfy these conditions in a well-balanced manner, if not completely.

Examples of resins with such characteristics include silicone resins and epoxy resins.

Silicone resin is suitable as a sealing material for high-frequency devices and power devices because it has excellent heat resistance and electrical properties at high temperatures, but it has poor sealing properties for lead frames and insufficient moisture resistance. Furthermore, the field of application is limited because it is more expensive than epoxy resins.

On the other hand, upoxy resin has excellent sealing properties for lead frames, good electrical properties, and is inexpensive, so it is widely used as a sealing material for semiconductor devices.

Transfer molding using epoxy resin is commonly used as a sealing method for semiconductor devices such as ICs and LSIs, but its moisture resistance is inferior to conventional hermetically sealed products.

In other words, when moisture enters a molded body made of epoxy resin from the outside, the insulation properties of the resin decrease, causing an increase in leakage current, and the functionality of the semiconductor device decreases. Therefore, it is difficult to completely remove chlorine ions, and alkaline ions such as sodium ions are also contained in resins and fillers, and resins absorb moisture and are exposed to high temperatures and electric fields for long periods of time. Over time, these ions become liberated and corrode the wiring made of aluminum, resulting in a decrease in reliability.

As a solution to this problem, methods have been taken such as selecting materials with low impurity content, using organic phosphoric acid compounds or organic boric acid compounds as curing accelerators, and making the surface of the aluminum conductor Bakoon a passivation material. has not been sufficiently effective.

(C) Problems to be Solved by the Invention The purpose of the present invention is to provide a composition of an epoxy resin sealing material that has improved moisture resistance compared to the conventional one. The purpose of the present invention is to improve moisture resistance by improving the adhesion of the mixed filler to the resin, to prevent the penetration of moisture, and thereby to prevent the release of corrosive ions. This can be achieved by coating the inorganic filler mixed with the epoxy resin with a thin film of organopolysilsesquioxane beforehand.

<e> Effect The present invention improves the adhesion between the inorganic filler and the epoxy resin by applying a silicone resin liquid consisting of an organopolysilsesquioxane represented by the following structural formula and an organic solvent to the surface of the inorganic filler. It is something.

Examples of the organopolysiloxane include methylpolysilsesquioxane, phenylpolysilsesquioxane, and methylphenylpolysilsesquioxane.

The organic solvent may be any solvent or dispersion medium that dissolves the silicone compound, but preferable examples include benzene, toluene, methyl isobutyl ketone, and butyl cellosolve acetate.

1 Here, R1 and R2 represent an organic group such as methyl or phenyl.

The concentration of the silicone resin liquid of the present invention is limited to a range of 1 to 50% by weight, and if it is less than 1% by weight, sufficient effects will not be exhibited, while if it is more than 50% by weight, the thickness of the silicone film formed will be reduced. It became too large and cracks occurred in the film.

The method for applying the silicone resin liquid according to the present invention is to completely immerse the inorganic filler in the silicone resin liquid and mix it thoroughly, then filter it, dry it at 250 to 350°C, and fill the epoxy resin molding material. shall be.

Next, the epoxy resin used in the present invention may be, for example, bisphenol A epoxy, novolac epoxy, heterocyclic epoxy, etc., and an appropriate curing agent, curing accelerator, and mold release agent.

Use with addition of coloring agents, etc.

Examples of the inorganic filler used in the present invention include crystalline silica powder, quartz glass powder, calcium silicate, and glass fiber.

(f) Example 1 Quartz glass with a particle size of several 10 μm was immersed in a toluene solution of methylpolysilsesquioxane (concentration 30%), thoroughly mixed, filtered, and heated at a temperature of 250 to 350°C for 1 hour. Dry.

To 350 g of this filler, 100 g of Talezol noholanc type epoxy resin, 15 g of brominated epoxy resin, 15 g of antimony trioxide, 50 g of phenol novolac resin,
2-methylisidazole 2g, carphone black 2g,
2 g of Karnahawasox was mixed in a kneader and kneaded well to prepare an epoxy resin molding material.

Next, using this material, a semiconductor integrated circuit was sealed at 170° C. for 3 minutes.

121 for the 40 test samples obtained in this way.
A pressure puller bias test was carried out under the conditions of 'C, 2 atmospheres, humidity 95%, and DC 15V applied to examine the moisture resistance and corrosion resistance.

In this evaluation method, an aluminum test piece with a width of 10 μm and a thickness of 1 μm is judged to be defective if it corrodes and breaks.
The number of defects that occurred over time was investigated.

As a result, the defect rate was 0 after 50 hours.

1 item after 100 hours and 1 item after 150 hours.

After 200 hours, there were 3 pieces.

On the other hand, when untreated quartz glass was used as a filler and the same number of pieces were subjected to a pressure puller bias test using the same method, the failure rate after 50 hours was 15.
After 100 hours, the number was 38, showing a remarkable difference.

(g) As described in the detailed description of the invention, by coating an inorganic filler with organopolysilsesquioxane and sealing with a resin using such a filler, the corrosion resistance of electronic components, especially semiconductor components, is improved compared to conventional methods. can be significantly improved.

Claims (1)

[Claims] An inorganic filler mixed into an epoxy resin for encapsulating electronic components is used by coating the filler with a thin film of organopolysilsesquioxane and mixing. Exhaust epoxy resin sealing material.