JPH07228671A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain a resin composition consisting essentially of an epoxy resin, a phenolic novolak resin, an alkylidenetriphenylphosphorane and an inorganic filler, excellent in packing property of a thin type semiconductor package and free from non-packing, void and die pat shift. CONSTITUTION:This resin composition consists essentially of an epoxy resin (e.g. cresol novolak type epoxy), a phenolic novolak resin, preferably 0.01-1.50wt.% of an alkylidenetriphenylphosphorane of the formula [X and Y are each H, an alkyl, a cyclic alkyl, an aryl, CH=CHR (R is a 1-5C alkyl), CidenticalN, OR, etc.] and an inorganic filler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly reliable resin composition for encapsulating a semiconductor, which has excellent reactivity during molding.

[0002]

2. Description of the Related Art Transfer molding of epoxy resin is adopted as a method for sealing semiconductor elements such as transistors, ICs, LSIs, etc. as a method suitable for low-cost mass production, and is sufficiently used by improving epoxy resin in terms of reliability. Is a level that can withstand. On the other hand, as semiconductor packages have become thinner and more highly integrated, how to reduce the package thickness has become important.As a resin for semiconductor encapsulation, the thin-walled part has excellent filling properties, and moisture and impurities from the outside It is required that the thin resin layer prevent the penetration of
Conventionally, a method of reducing the particle size of the filler or lowering the resin viscosity has been used for sealing a thin package.
There is a limit when the internal chip size is large and there is no filling,
Internal voids were generated, leading to a decrease in reliability. In addition, there is a method of applying a sufficient injection pressure by decreasing the amount of the curing accelerator and slowing the curing speed for the purpose of improving the filling property, but this causes a problem in that the molding cycle becomes long.

[0003]

The present invention provides a resin composition for semiconductor encapsulation for improving the filling property and molding cycle during molding of such a semiconductor product.

[0004]

The present invention relates to a resin composition for semiconductor encapsulation which contains an epoxy resin, a phenol novolac resin, an alkylidenetriphenylphosphorane represented by the following formula (1) and an inorganic filler as essential components. is there.

[0005]

[Chemical 2]

The epoxy resin used in the present invention may be any one used in ordinary resin compositions for semiconductor encapsulation, for example, cresol novolac type epoxy, trifunctional epoxy, biphenyl type epoxy, bisphenol type epoxy, brominated epoxy. However, it is not particularly limited. These epoxy resins can be used alone or
May be used together. The phenol novolac resin as the curing agent may be one used in a usual semiconductor encapsulating resin composition, and examples thereof include phenol novolac type, cresol novolac type, xylene type, dicyclopentadiene type and modified resins thereof. It is not particularly limited. These may be used alone or in combination. The amount of these curing agents to be added is preferably such that the number of epoxy groups in the epoxy resin matches the number of hydroxyl groups in the curing agent. As the inorganic filler, silica, alumina, and silicon nitride may be used alone or in combination. A combination of spherical silica and crushed silica is preferably selected from the viewpoints of fluidity and prevention of burr.

The alkylidene triphenylphosphorane, which is the curing accelerator used in the present invention, is derived from triphenylphosphine. The strong basicity and nucleophilicity of the alkylidene group and the affinity for the epoxy group of the phosphorus atom exert an effective catalytic action, and a resin composition having low viscosity, excellent filling property, and fast curability can be obtained. By selecting a sterically bulky phenyl group or the like for the alkylidene group, the strength of activity can be adjusted, and the viscosity, fluidity and curing speed can be optimized.
The alkylidene group is = CXY, and X and Y are hydrogen, an alkyl group, a cyclic alkyl group, an aryl group, and -CH = CH.
R, -COR, -C≡N, -COOR, -OR, and R is an alkyl group having 1 to 5 carbon atoms. Of these, X is preferably hydrogen, and Y is preferably -C≡N or -COOC ₂ H ₅ . The amount of addition is preferably 0.01 to 1.5% by weight in the total resin composition. X and Y may be the same or different, but may be one kind or a combination of two or more kinds of alkylidenetriphenylphosphoranes having different substituents depending on the use. In addition, imidazole, tertiary amine,
It may be combined with a curing accelerator such as 1,8, -diazabicycloundecene or triphenylphosphine. If the addition amount is less than 0.01% by weight, the curability is poor, and if it exceeds 1.5% by weight, no further effect can be expected. The resin composition using the alkylidenetriphenylphosphorane of the present invention exhibits unique reactivity and high reactivity at the time of molding, and on the other hand, has excellent storage stability at room temperature, and thus can be economically used.

Production Example of Curing Accelerator Formula (2) is hereinafter referred to as Ph ₃ P.

[0009]

[Chemical 3]

Production Example 1 Ph ₃ P = CHCN Ph ₃ PBr ₂ and CH ₃ CN in benzene were reacted at 80 ° C. for 24 hours in the presence of a tertiary amine to obtain Ph ₃ P═CHCN, and impurities were removed by recrystallization. It was Melting point 190 [deg.] C. Production Example 2 Ph ₃ P = CHCO ₂ C ₂ H ₅ Ph ₃ P in benzene and BrCH ₂ CO ₂ C ₂ H ₅ were reacted for 24 hours at 40 ° C. and recrystallized to form a phosphonium salt (Ph
₃ PCH ₂ CO ₂ C ₂ H ₅ ) ⁺ Br ⁻ was obtained. Next (Ph ₃ PC
H ₂ CO ₂ C ₂ H ₅ ) ⁺ Br ⁻ was refluxed in ethanol in the presence of triethylamine at 80 ° C., Ph ₃ P═CHCO ₂ C ₂
H ₅ was obtained. Melting point 117 [deg.] C.

In the present invention, an epoxy resin, a phenol novolac resin, an alkylidene triphenylphosphorane, and an inorganic filler are essential components. In addition to these, a silane coupling agent, a brominated epoxy resin, antimony trioxide, hexa Flame retardants such as brombenzene, colorants such as carbon black and red iron oxide, mold release agents such as natural wax and synthetic wax, and various additives such as low-stress additives such as silicone oil and rubber may be appropriately blended. Absent. Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, the epoxy resin, the phenol novolac resin, the alkylidene triphenylphosphorane, the inorganic filler, and the other additives are sufficiently homogenized by a mixer or the like. After mixing, the mixture can be further melt-kneaded with a hot roll or a kneader, cooled and pulverized to obtain a sealing material.

[0012]

EXAMPLES The present invention will be described below with reference to examples. The blending ratio is shown in parts by weight. Example 1 Biphenyl type epoxy resin (Oilized shell YX4000H, epoxy equivalent 190, melting point 170 ° C.) 90 parts by weight Brominated epoxy resin (Nippon Kayaku BREN epoxy equivalent 270, softening point 70 ° C.) 10 parts by weight Phenol novolac resin ( Sumitomo Durez Hydroxyl equivalent 104, softening point 80 ° C) 47 parts by weight Spherical silica (maximum particle size 74 microns, average particle size 25 microns) 500 parts by weight Fused silica (crushing type maximum particle size 30 microns, average particle size 5 microns) 100 Parts by weight Ph ₃ P = CHCN (melting point 190 ° C.) 4 parts by weight γ-glycidoxypropyltrimethoxysilane (Nippon Unicar) 5 parts by weight antimony trioxide 8 parts by weight carnauba wax 3 parts by weight carbon black 2 parts by weight at room temperature Mix well, then use a biaxial hot roll at 80-100 ° C To obtain a resin composition for semiconductor encapsulation was pulverized kneaded and cooled. Examples 2 to 4 A resin composition for semiconductor encapsulation was obtained in the same manner as in Example 1 with the formulations shown in Table 1. Comparative Examples 1 to 4 Using the formulations shown in Table 1, a resin composition for semiconductor encapsulation was obtained in the same manner as in Example 1. The resin compositions for semiconductor encapsulation of Examples and Comparative Examples were heated at a temperature of 175 ° C. using a transfer molding machine.
Molding was performed at an injection pressure of 120 kg / cm ² to obtain a test piece for evaluation.

Evaluation Method Fillability: Fillability into a thin QFP having a package size of 28 × 28 × 1.4 mm and a chip size of 14 × 14 × 0.3 mm was judged by the degree of occurrence of voids and die pad shift. Curability: Based on gel time (175 ° C. heating plate) and high-flow type flow viscosity (175 ° C.) as base data, the shortest possible molding time was evaluated at 175 ° C. by a multi-transfer molding machine with 1 pot and 4 cavities. Moisture resistance reliability: 300 mil SOP using simulated element,
After moisture absorption treatment at 85 ° C, 85% RH for 72 hours, soldering treatment at 260 ° C for 10 seconds, and then P at 100% RH at 125 ° C.
It was judged by the number of defects after 500 hours of CT treatment. Storability: Material powder is stored at 25 ° C, and EMMI-I
The spiral flow was measured at 175 ° C. with a mold according to −66, and the spiral flow residual rate was evaluated after 4 days at 25 ° C. Table 1 shows the above evaluation results.

[0014]

[Table 1]

[0015]

According to the method of the present invention, it is possible to obtain an epoxy resin composition for semiconductor encapsulation, which is excellent in the filling property of a thin semiconductor package, and which has been difficult to mold conventionally by 1.5 mm.
It is possible to solve the problems such as unfilling of a semiconductor package having a thickness of not more than, voids, and die pad shift, and to obtain a highly reliable semiconductor package.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 23/31

Claims (3)

[Claims] 1. A resin composition for semiconductor encapsulation, which comprises an epoxy resin, a phenol novolac resin, an alkylidenetriphenylphosphorane represented by the following formula (1), and an inorganic filler as essential components. [Chemical 1] 2. An alkylidenetriphenylphosphorane represented by the formula (1), wherein X is hydrogen, Y is —C≡N, or —CO.
The resin composition for semiconductor encapsulation according to claim 1, which is OC ₂ H ₅ . 3. The alkylidene triphenylphosphorane represented by the formula (1) is added to the entire resin composition in an amount of 0.01 to 1.50.
The resin composition for semiconductor encapsulation according to claim 1 or 2, which contains the resin in a weight percentage.