JPH11166074A - Epoxy resin composition for sealing semiconductor and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition capable of exhibiting excellent moisture resistance by making the composition include an epoxy resin, a phenol resin-curing agent, a curing accelerator, an inorganic filler, an ion-capturing agent and surface-treated aluminum nitride. SOLUTION: This composition comprises (A) an epoxy resin, (B) a phenolic resin-curing agent, (C) a curing accelerator, (D) an inorganic filler, (E) an ion- capturing agent, and (F) aluminum nitride whose surface is oxidized, wherein the component F is contained in an amount of 5-25 wt.% in the total resin composition. The component (F) is easily obtained by oxidizing silicon nitride particles in air at about 1,200 deg.C. The component F preferably has an average particle diameter of 0.1-50 μm, the maximum particle diameter of <=150 μm and further a powdery shape. The composition is obtained by mixing the components (A) to (F), further melt-kneading the mixture with a roll or the like, cooling the product, and subsequently crushing the solidified product into proper sizes. A highly reliable semiconductor can thereby be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable epoxy resin composition for semiconductor encapsulation having excellent moisture resistance, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Semiconductor elements such as transistors, ICs, and LSIs have been adopted because a method of sealing with an epoxy resin composition (hereinafter referred to as a resin composition) is suitable for low cost and mass production. In terms of reliability, it is at a level that can withstand use by improving the progress of epoxy resin. However, in recent years, with the increase in the degree of integration of semiconductors, the corrosion of aluminum wiring has started to occur early due to the reduction in the width of aluminum wiring on IC chips. This corrosion is promoted by the presence of moisture absorbed by the cured product of the resin composition, and it has been required to further improve the anticorrosion effect and moisture resistance of the cured product of the resin composition. Regarding the mechanism of corrosion of aluminum wiring, Kaino (Applied Physics, 49, (198)
According to the review of 0)), it is known that the presence of ionic impurities such as Cl and Na promotes the progress of corrosion. In the resin composition for semiconductor encapsulation, trace amounts of ionic impurities due to raw materials are present, and corrosion of aluminum wiring is promoted. Therefore, these resin compositions usually trap ionic impurities. An ion scavenger is included. Although the moisture resistance has been considerably improved by using a resin composition containing an ion scavenger, some of them have not been able to cope with recent diversifying use conditions of semiconductor devices.

[0003]

SUMMARY OF THE INVENTION The present invention provides an epoxy resin composition for encapsulating a semiconductor having excellent moisture resistance and a semiconductor device using the same.

[0004]

That is, the present invention provides (A)
In a resin composition comprising an epoxy resin, (B) a phenolic resin curing agent, (C) a curing accelerator, (D) an inorganic filler, (E) an ion scavenger, and (F) silicon nitride whose surface is oxidized. And an epoxy resin composition for semiconductor encapsulation, wherein the total resin composition contains 5 to 25% by weight of silicon nitride whose surface is oxidized.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention includes, for example, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin,
Cresol novolak epoxy resin, phenol novolak epoxy resin, brominated epoxy resin, triphenolmethane epoxy resin, alkyl-modified triphenolmethane epoxy resin, triazine nucleus-containing epoxy resin, dicyclopentadiene-modified phenol epoxy resin, etc. However, the present invention is not limited to these. These epoxy resins may be used alone or in combination.

The phenolic resin curing agent used in the present invention includes, for example, phenol novolak resin, cresol novolak resin, xylylene-modified phenol resin,
Examples include, but are not limited to, dicyclopentadiene-modified phenolic resins and terpene-modified phenolic resins. These phenol resins may be used alone or as a mixture.

The curing accelerator used in the present invention includes:
Any substance that promotes the reaction between the epoxy group and the phenolic hydroxyl group may be used, and those generally used in resin compositions can be widely used. For example, tertiary amines such as benzyldimethylamine, Imidazoles such as -methylimidazole, 1,8-diazabicyclo (5,
Organic phosphorus compounds such as (4,0) undecene-7 and triphenylphosphine are exemplified, but not limited thereto. These curing accelerators may be used alone or in combination. As the inorganic filler other than silicon nitride used in the present invention, for example, crystalline silica, fused silica,
Secondary agglomerated silica, alumina and the like can be mentioned, and these may be used alone or in combination. Examples of the ion scavenger used in the present invention include bismuth compounds and hydrotalcite compounds which can be used in this field, and these may be used alone or as a mixture.

The inventor of the present invention believes that, in addition to the ionic impurities in the resin composition, phenolic hydroxyl groups, which are considered to be present as unreacted components in the cured product, promote corrosion and the like and adversely affect moisture resistance. As a result of presumption and various studies, it has been found that by incorporating silicon nitride whose surface is oxidized into the resin composition, the semiconductor device sealed with the resin composition has improved moisture resistance. That is, by using a resin composition containing silicon nitride whose surface is oxidized, when the semiconductor device absorbs moisture, that is, when the cured product of the resin composition absorbs moisture, the system of the cured product shifts to the acidic side. It is believed that the silicon nitride prevents too much. This is because silicon nitride whose surface has been oxidized reacts with moisture to generate alkaline ammonia, reacts with phenolic hydroxyl groups, which are presumed to be a factor in corrosion, and prevents the adverse effects of phenolic hydroxyl groups in the cured product. It is thought to be.

In a resin composition containing silicon nitride whose surface has not been oxidized, the silicon nitride easily reacts with moisture in the air during storage, significantly lowering the storage stability and deteriorating the curability. There were drawbacks. The silicon nitride of the present invention whose surface has been oxidized can be easily obtained by oxidizing fine powder silicon nitride in air at about 1200 ° C. Since the surface is silicon oxide, it does not react with moisture, so that the resin composition It does not lower the storage stability and curability of the product. As the silicon nitride of the present invention whose surface has been oxidized, those having an average particle size of 0.1 to 50 μm and a maximum particle size of 150 μm or less are preferable for improving the fluidity of the resin composition.
Although the shape is not particularly limited, for example, a powder is preferable. The content is 5 to 25% by weight in the total resin composition.
Is preferred. If the amount is less than 5% by weight, the system of the cured product is on the acidic side, and if it exceeds 25% by weight, the system of the cured product is on the alkaline side, and the moisture resistance is undesirably reduced.

[0010] The resin composition of the present invention may further comprise, if necessary, a natural wax, a synthetic wax,
Release agents such as higher fatty acids and their metal salts, paraffin,
Brominated epoxy resin, hexabromobenzene, decabromobiphenyl ether, antimony trioxide, flame retardant such as phosphorus compound, carbon black, coloring agent such as red iron,
A silane coupling agent, an antioxidant, a low-stress component such as silicone oil or silicone rubber, a thermoplastic resin, or the like can be appropriately added and blended. The resin composition of the present invention is prepared by sufficiently mixing the components (A) to (F) and other additives with a mixer or the like, and then melt-kneading with a roll or a kneader and solidifying by cooling. It can be crushed to a suitable size. In order to manufacture a semiconductor device by encapsulating an electronic component such as a semiconductor using the resin composition of the present invention, it is only necessary to cure and mold by a conventional molding method such as transfer molding, compression molding and injection molding.

[0011]

The present invention will be specifically described below with reference to examples.
However, the present invention is not limited to these examples. The mixing unit is parts by weight. Example 1 Cresol novolak type epoxy resin (epoxy equivalent 200, softening point 70 ° C) 90 parts by weight Phenol novolak resin (hydroxyl equivalent 104, softening point 110 ° C) 50 parts by weight 1,8-diazabicyclo (5,4,0) undecene -7 parts (hereinafter referred to as DBU) 2 parts by weight Fused silica (RD-8, manufactured by Tatsumori Co., Ltd.) 460 parts by weight Ion scavenger (Bi ₆ O ₆ (OH) _4.2 (NO ₃ ) _1.8 , true specific gravity 7 .06) 1 part by weight Silicon nitride whose surface is oxidized (average particle diameter 12 μm, specific surface area 1 m 2 / g) 40 parts by weight Carnauba wax 3 parts by weight Brominated epoxy resin (epoxy equivalent 270, softening point 70 ° C.) 10 parts by weight Parts Antimony trioxide 9 parts by weight Carbon black 2 parts by weight γ-ureidopropyltriethoxysilane 2 parts by weight γ-mercaptopropyltrimethoate 1 part by weight of xysilane is sufficiently mixed at room temperature, then kneaded at 80 to 100 ° C. using a biaxial hot roll, cooled, pulverized to form a tablet,
A resin composition was obtained. This resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Storage stability: Using a mold for spiral flow measurement according to EMMI-I-66, mold temperature 175 ° C., injection pressure 70
The spiral flow retention was determined by measuring at kg / cm ² and curing time of 2 minutes. The spiral flow retention is a value obtained by storing the resin composition at room temperature for 48 hours as a percentage (unit:%) with respect to the initial spiral flow value. Judged. Moisture resistance: Using a transfer molding machine, mold temperature 17
16pDIP for testing (chip size 3mm × 3.5m) at 5 ° C, injection pressure 70kg / cm ² , curing time 120 seconds
m), followed by post-curing for 4 hours at 175 ° C., and then using a pressure cooker at 125 ° C.
The device was placed under 2.3 atm and the current value between the leads was measured over time, and the time until the leakage current became 10 nA or more was measured. The unit is time.

Examples 2 and 3 Compounded according to the formulation shown in Table 1, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. Comparative Examples 1-3 Compounded according to the formulation shown in Table 1, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. The silicon nitride whose surface was not oxidized used in Comparative Example 4 had an average particle size of 25 μm and a specific surface area of 0.8 m ² / g.

[Table 1]

[0014]

The epoxy resin composition for encapsulating a semiconductor of the present invention has excellent moisture resistance and can provide a highly reliable semiconductor device.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/31

Claims (2)

[Claims] 1. An epoxy resin, (B) a phenol resin curing agent, (C) a curing accelerator, (D) an inorganic filler,
(E) In a resin composition comprising an ion scavenger and (F) a silicon nitride having a surface oxidized, the total resin composition contains 5 to 25% by weight of silicon nitride having a surface oxidized. An epoxy resin composition for semiconductor encapsulation characterized by the following. 2. A semiconductor device which is encapsulated with the epoxy resin composition for semiconductor encapsulation according to claim 1.