JP3226407B2 - Resin composition for semiconductor encapsulation - Google Patents

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 semiconductor encapsulation having excellent reactivity during molding.

[0002]

2. Description of the Related Art As a method for encapsulating semiconductor elements such as transistors, ICs and LSIs, a method by transfer molding of epoxy resin is adopted as a method suitable for low-cost mass production, and the reliability is sufficiently used by improving the epoxy resin. It is a level that can withstand. On the other hand, semiconductor packages are becoming thinner and more highly integrated, and it is becoming increasingly important to reduce the package thickness. It is required that a thin resin layer can prevent the infiltration of water.
Conventionally, for sealing thin packages, methods of reducing filler particle size and reducing resin viscosity have been used.
If the internal chip size is large, there is a limit and unfilled or
Internal voids were generated, leading to a decrease in reliability. In addition, there is a method of applying a sufficient injection pressure by reducing the amount of a curing accelerator and decreasing the curing speed for the purpose of improving the filling property, but there is a problem that the molding cycle becomes long.

[0003]

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

[0004]

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

[0005]

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[0006] The epoxy resin used in the present invention may be any resin used in a usual resin composition for encapsulating a semiconductor, such as cresol novolak epoxy, trifunctional epoxy, biphenyl epoxy, bisphenol epoxy, brominated epoxy. And the like, but are not particularly limited. These epoxy resins can be used alone or
May be used in combination. The phenol novolak resin of the curing agent may be any one used in a usual resin composition for semiconductor encapsulation, and examples thereof include phenol novolak type, cresol novolak type, xylene type, dicyclopentadiene type and modified resins thereof. However, there is no particular limitation. These may be used alone or in combination. The amount of the curing agent is preferably such that the number of epoxy groups in the epoxy resin is equal to the number of hydroxyl groups in the curing agent. As the inorganic filler, silica, alumina, or silicon nitride may be used alone or in combination. Preferably, a combination of spherical silica and crushed silica is selected from the viewpoint of fluidity and prevention of burrs.

[0007] Alkylidenetriphenylphosphorane, a 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 properties, and fast curability can be obtained. By choosing a sterically bulky phenyl group or the like for the alkylidene group, the strength of the activity can be adjusted, and the viscosity, fluidity, and curing speed can be optimized.
The alkylidene group is ＣCXY, X is hydrogen, and Y is-
C≡N or X is hydrogen, Y is -COOR, R is Ri alkyl der of 1 to 5 carbon atoms, the X among these hydrogen,
Y is preferably -COOC ₂ H _5. The amount added is preferably 0.01 to 1.5% by weight in the whole resin composition. X and Y may be the same or different, but one or a combination of two or more alkylidene triphenylphosphoranes having different substituents may be used depending on the application. Further, it may be combined with a curing accelerator such as imidazole, tertiary amine, 1,8, -diazabicycloundecene and triphenylphosphine. If the amount is less than 0.01% by weight, the curability is poor, and if it exceeds 1.5% by weight, further effects cannot be expected. The resin composition using the alkylidene triphenylphosphorane of the present invention has a unique reactivity and a high reactivity at the time of molding, and has excellent storage stability at room temperature, so that it can be used economically.

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

[0009]

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Production Example 1 Ph ₃ P = CHCN Ph ₃ PBr ₂ and CH ₃ CN in benzene are reacted for 24 hours at 80 ° C. in the presence of a tertiary amine to obtain Ph ₃ P = CHCN, and impurities are removed by recrystallization. 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 at 40 ° C. for 24 hours, and the phosphonium salt (Ph) was recrystallized.
₃ PCH ₂ CO ₂ C ₂ H ₅ ) ⁺ Br ⁻ was obtained. Then (Ph ₃ PC
H ₂ CO ₂ C ₂ H ₅ ) ⁺ Br ⁻ was refluxed in ethanol in the presence of triethylamine at 80 ° C. to obtain Ph ₃ P = CHCO ₂ C ₂
It was obtained H _5. 117 ° C.

The present invention comprises an epoxy resin, a phenol novolak resin, an alkylidene triphenylphosphorane and an inorganic filler as essential components. In addition to these, a silane coupling agent, a brominated epoxy resin, antimony trioxide, hexane Various additives such as a flame retardant such as bromobenzene, a coloring agent such as carbon black and red bean, a release agent such as natural wax and synthetic wax, and a low stress additive such as silicone oil and rubber may be appropriately compounded. Absent. Further, in order to produce the sealing epoxy resin composition of the present invention as a molding material, epoxy resin, phenol novolak resin, alkylidene triphenylphosphorane, inorganic filler, and other additives are sufficiently uniformly mixed by a mixer or the like. After mixing, the mixture is further melt-kneaded by a hot roll or a kneader, cooled, and pulverized to obtain a sealing material.

[0012]

The present invention will be described below by way of examples. The mixing ratio is shown in parts by weight. Example 1 90 parts by weight of a biphenyl-type epoxy resin (Yushi 4000 YH, 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 novolak resin Sumitomo Durez, hydroxyl equivalent 104, softening point 80 ° C) 47 parts by weight Spherical silica (maximum particle diameter 74 microns, average particle diameter 25 microns) 500 parts by weight Fused silica (crushed type maximum particle diameter 30 microns, average particle diameter 5 microns) 100 Parts by weight Ph ₃ P = CHCN (melting point 190 ° C.) 4 parts by weight γ-glycidoxypropyltrimethoxysilane (Nihon 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 twin-screw 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 encapsulating a semiconductor was obtained in the same manner as in Example 1 with the composition shown in Table 1. Comparative Examples 1 to 4 Resin compositions for semiconductor encapsulation were obtained in the same manner as in Example 1 with the formulations shown in Table 1. The temperature of the resin composition for semiconductor encapsulation of Examples and Comparative Examples was 175 ° C. using a transfer molding machine.
A test piece for evaluation was obtained by molding at an injection pressure of 120 kg / cm ² .

Evaluation Method Fillability: The fillability of a thin QFP having a package size of 28 × 28 × 1.4 mm and a chip size of 14 × 14 × 0.3 mm was determined based on the degree of void and die pad shift. Curability: The shortest moldable time was evaluated at 175 ° C. with a one-pot, four-cavity multi-transfer molding machine, using gel time (175 ° C. hot plate) and high-flow flow viscosity (175 ° C.) as base data. Moisture resistance reliability: 300 mil SOP using simulated element,
85 ° C., 85% RH, 72 hours moisture absorption, 260 ° C. soldering for 10 seconds, 125 ° C., 100% RH P
Judgment was made based on the number of defects after 500 hours of CT processing. Storage property: Store the material powder at 25 ° C and use EMMI-I
The spiral flow was measured at 175 ° C. with a mold according to −66, and the spiral flow residual rate after 4 days at 25 ° C. was evaluated. Table 1 shows the 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.
Problems such as unfilling, voids, and die pad shift of a semiconductor package having a thickness of less than the thickness can be solved, and a highly reliable semiconductor package can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI (C08K 13/02 C08K 5:50) 3:00 H01L 23/30 R 5:50) (58) Field surveyed (Int.Cl. . ^7, DB name) C08L 63/00 - 63/10 C08K 5/50 C08G 59/68 H01L 23/29

Claims (3)

(57) [Claims] 1. A resin composition for semiconductor encapsulation, comprising an epoxy resin, a phenol novolak resin, an alkylidene triphenylphosphorane represented by the following formula (1), and an inorganic filler as essential components. Embedded image 2. The resin composition for semiconductor encapsulation according to claim 1 , wherein X of the alkylidene triphenylphosphorane represented by the formula (1) is hydrogen and Y is —COOC ₂ H ₅ . 3. An 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 encapsulating a semiconductor according to claim 1, wherein the resin composition comprises 1% by weight.