JPS61113642A - Epoxy resin composition for semiconductor sealing use - Google Patents

Abstract

PURPOSE:To obtain the titled composition with high moisture resistance and high crack resistance when subjected to heat shock, by incorporating an epoxy resin with as filler, specific spherical silica treated for providing the surface with hydrophobicity. CONSTITUTION:The objective composition can be obtained by incorporating (A) an epoxy resin with (B) spherical or crushed-type silica as filler with a weight-average size <=15mu and maximum size <=100mu, treated with alkoxysilane or titanate for providing its surface with hydrophobicity. The amount of the above treating agent to be used should be 0.2-5pts.wt. per 100pts.wt. of the silica.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an epoxy resin composition for semiconductor encapsulation that has excellent crack resistance and moisture resistance when subjected to thermal shock. Its feature is that silica with a hydrophobic surface is used as a filler.

[Prior art]

Conventionally, a coupling agent is used in an epoxy resin composition for semiconductor encapsulation to bond a filler and a resin. The purpose of this is to connect the filler/resin interface and increase the strength of the composition. Silane-based clogging agents (epoxysilane, aminosilane, vinylsilane, etc.)
is mainly used. As the filler, silica having an average particle diameter of 2.degree. microns and a maximum particle diameter of 150 microns is used.

However, recently there has been a strong demand for lower stress in these applications. This is to internationalize the final product, allowing it to be used at any time and place. That is, because they are used in many different ways and by many people, they are required to be strong against rough handling and storage. Furthermore, there has been a need to reduce the particle size of silica. The particle size of silica is 100
If it is more than a micron, it will be too large, that is, it will be microscopically non-uniform, and the connection between the semiconductor element and the lead will be deformed (wire deformation).
This is because it has been found that this causes resin cracks to occur. In particular, the sealing resin thickness is 300~
This is becoming a big problem with 500 micron flat packages.

Current compositions cannot meet these demands. In current compositions, the silica/resin is tightly bound to the lintel, making the final product hard and brittle. Also, silica is too coarse.

[Purpose of the invention]

The present invention is the result of research aimed at fundamentally improving epoxy resin compositions for semiconductor encapsulation, which conventionally had problems with crack resistance and moisture resistance, and developing practical products for application at an industrial/industrial level. It has been discovered that an epoxy resin composition for semiconductor encapsulation having excellent crack resistance and moisture resistance can be obtained by hydrophobicizing the surface of silica with alkoxysilanes or titanates.

[Structure of the invention]

The present invention is characterized in that crushed or spherical silica having an average particle size of 15 microns or less and a maximum particle size of 100 microns or less, the surface of which has been previously hydrophobized with alkoxysilanes or titanates, is used as a filler. This is an epoxy resin composition for semiconductor encapsulation. Silica here refers to crushed or spherical silica with an average particle size of 15 microns or less and no particles larger than 100 microns, and for semiconductor encapsulation applications, it is preferable that the electrolyte contains few impurities or foreign substances. .

Alkoxysilanes and titanates have functional groups (silanol groups, methoxy groups, etc.) to react with silica, and are commercially available as alkoxysilanes.
-3037, 5R-2402, 5H-6200 ()-Le Silicone Co., Ltd.), KR-213, version-216, l0
Examples include 3M-13 (Shin-Etsu Chemical Co., Ltd.) MTS, PTS series (Otona Chemical Industry Co., Ltd.), and the like.

Preferably, it is oligomerized. Oligomerization increases the effect of stress relief. In addition, as titanates, KEN-REACT series (Ke
nrich Petrochemical Inc.)
etc. can be mentioned. One or more types of alkoxysilanes and titanates may be used. Here, it is essential to mix silica with alkoxysilanes or titanates in advance to form a coating with a treatment agent on the silica surface. This provides the low stress and high moisture resistance properties that are the object of the present invention.

Generally, epoxy resin compositions for semiconductor encapsulation are made of resin, silica, and are often mixed with a curing agent, a curing accelerator, a mold release agent, a flame retardant, a pot treatment agent, a pigment, and the like. In particular, currently common materials include cresol novolak type epoxy resin, phenol novolac (curing agent), tertiary amine (curing accelerator), silica (filler), silica/coupling agent (,
It is composed of a processing agent), antimony trioxide (a flame retardant), etc., and the amount of silica is usually 50 to 90% by weight.

Now, as a result of analyzing semiconductor products that were reliable but failed, we found that the defective phenomenon was caused by a defective model diagram (for example) of a 16-bit memo IJ-IC enclosed product with an At circuit (1) and a protective film (2). As shown in Figures 1 to 3), due to the influence of the large filler (3), ■Water intrusion due to the occurrence of microcracks (4) at the resin bulk/resin interface;■Cracks in the circuit protection film (passivation film) ( Most of the causes were due to water intrusion due to damage caused by 5), and circuit abnormalities caused by (6) distortion of the aluminum circuit. As a result of further detailed investigation, it was found that these causes were silica and the coupling agent. It was found that large silica was always present in the areas where defects occurred, and there was little silica in the surrounding area (the filler was unevenly distributed). That is, it was found that the current silica particle size has a large variation and the stress is locally non-uniform. Furthermore, microcracks and peeling phenomena were observed in the coupling agent layer at the filler/resin interface by observation using an electron microscope or the like. In other words, it has been found that the current coupling agents have insufficient stress relieving effects.

Therefore, if crushed or spherical silica with an average particle diameter of 15 microns or less and a maximum particle diameter of 100 microns or less, whose surface has been hydrophobized with alkoxysilanes or titanates to form a buffer layer, is used as a filler, as described above. It was found that the number of defects was drastically reduced.

Also, the amount of processing agent added is 0.2/100 of silica.
5/100 is desirable. If the amount is too low, the effects of low stress and moisture resistance may not be obtained, and if the amount is too high, the formability (paris,
This is because curability) may become a problem.

〔Effect of the invention〕

As described above, according to the method of the present invention, an epoxy resin composition for semiconductor encapsulation having excellent crack resistance and moisture resistance can be obtained. Particularly in semiconductor encapsulation applications, it is expected that plastic packaging will be used more and more in the future, and as a result, low stress and high moisture resistance of plastics are required, and the present invention plays an extremely important role in industry.

〔Example〕

Hereinafter, an explanation will be given using a study example of an epoxy resin composition for semiconductor enclosure. All parts used in the examples are parts by weight. The examples according to the present invention are superior to the comparative examples according to the conventional technology in terms of moldability, moisture resistance, and crack resistance, and have high added value that can be used industrially.

Examples 1 to 5 Crushed silica with an average particle size of 10 microns or less and a maximum particle size of 100 microns or less (Denki Kagaku Kogyo 2FS-30)
Or spherical silica (Denki Kagaku Kogyo: FB-30) 70
Part and surface treatment agent B()-Le Silico-7:5R-240
2, If7s7 f: KR-TrS, Shinetsu: Phantom M
-13) Heat 1 part or 6 parts using a Neegoo,
After mixing at 20°C for 30 minutes, ortho-cresol novolac type epoxy resin (Japanese rate: EOCN-1020)
20 parts phenol novolac (Sumitomo Bakelite) 1
0 parts・Curing accelerator (KAI Kasei PP-360/Shikoku Kasei Kaga=9/1) 0.2 parts・Surface treatment agent A (Chisso: G
PS-M) 0.3 parts, pigment (Mitsubishi Kasei) 0.5 parts, mold release agent (Hoechst Japan Hoechst OP/Hoechst S = 1
/1) 0.4 parts were mixed and kneaded for 3 minutes with a hot roll at 80°C to obtain 5 types of molding materials.

The moldability, crack resistance, and moisture resistance of these molding materials were measured, and as shown in the table, they were superior to the comparative examples: 162, 8.9. 4
Comparative Examples 1 to 3 70 parts of crushed silica (Kikagaku Kogyo: FS-90) or spherical silica (Denki Kagaku Kogyo: FB-90) with an average particle diameter of 20 microns and a maximum particle diameter of 150 microns and a surface treatment agent After mixing 1 part of B at 120°C for 30 minutes using a heating kneader, 20 parts of epoxy resin, 10 parts of phenol novolac, 0.2 parts of curing accelerator, 3 parts of surface treatment agent A, and 0.5 part of pigment were added. - 0.4 part of mold release agent (all the same raw materials as in the example) was made into a material in the same manner as in the example. The moldability, moisture resistance, and crack resistance results of this material are shown in the attached table, and it is significantly inferior to the examples in terms of crack resistance and moisture resistance.

Comparative Example 4 70 parts of crushed silica, 20 parts of epoxy resin, 10 parts of phenol novolak, 0.2 part of curing accelerator, surface treatment agent A
0.3 part of pigment, 0.5 part of pigment, and 0.4 part of mold release agent (all the same raw materials as in the example) were made into materials in the same manner as in the example. The moldability, moisture resistance, and crack resistance results of this material are shown in the attached table, and it is significantly inferior to the examples in terms of moisture resistance and crack resistance.

Comparative Example 5.6 70 parts of crushed silica, 20 parts of epoxy resin, 10 parts of phenol novolac, 0.2 parts of Φ hardening accelerator, surface treatment agent A
13 parts O, 1 part surface treatment agent B, 0.5 parts pigment, 0 mold release agent
．． 4 parts (all the same raw materials as in the example) were mixed and kneaded for 3 minutes with a hot roll at 80°C to obtain two types of molding materials. The moldability, moisture resistance, and crack resistance results of this material are shown in the attached table, and it is significantly inferior to the examples in terms of moisture resistance and crack resistance.

* Judgment on the degree of paris on the lead bin when molding L 16 pin DIP When the distance to a part of the tie bar is less than h A, When L is less than B1 When Q~% is more than C1 (
D
, a thermal shock of 2150℃ (30 minutes) at room temperature (5 minutes)
Judging by the number of cracks generated/total number given by 0 cycles
200 cycles of thermal shock at 50°C (2 minutes) and judgment based on the number of cracks generated/total number *4 Moisture resistance, 16 pin sealed with aluminum simulated element
DIF was stored for 1000 hours at 135℃ and 100% condition, and the defective rate due to aluminum corrosion was determined by the number /&:

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are cross-sectional views of defective semiconductor products due to the influence of large fillers. -'>RR- Figure 1 Figure 2 Figure 3 Mouth opening ・Y■X1

Claims (1)

[Claims] A semiconductor characterized by using as a filler crushed or spherical silica having a weight average particle size of 15 microns or less and a maximum particle size of 100 microns or less, the surface of which has been hydrophobized with alkoxysilanes or titanates. Epoxy resin composition for sealing.