JP2551828B2 - Epoxy resin composition for semiconductor encapsulation - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an epoxy resin composition for use in semiconductor encapsulation, which retains a glass transition temperature, has a low elasticity and is significantly improved in heat shock resistance.

[Conventional Technology and Problems Thereof] Conventionally, a method of sealing electronic parts such as a diode, a transistor, an IC and an SLI with an epoxy resin has been used. This resin encapsulation is economically advantageous as compared with the hermetic sealing method using glass, metal, and ceramic, and is widely put into practical use. However, since this resin encapsulation directly seals the element by transfer molding, the element may be distorted or damaged due to the difference in the coefficient of linear expansion between the element and the resin, or thermal stress may occur, or the bonding wire may be cut. Therefore, it is desired to reduce the stress on the device. Particularly in recent years, the demand has become stronger and stronger with the increase in size and integration of semiconductor elements.
In order to reduce the stress, the material is devised so as to lower the elastic modulus and linear expansion coefficient of the cured product.

That is, a method of blending a flexibility-imparting agent is known as one method of reducing stress. However, when a flexibility-imparting agent such as conventionally known polypropylene glycol diglycidyl ether or bisphenol A type epoxy resin having a long side chain is compounded, the effect of lowering the elastic modulus is recognized, but the glass transition point is There is a problem that (Tg) drops sharply and the electrical characteristics at high temperature deteriorate.
Further, when the cresol novolac type epoxy resin is modified with a rubber having an unsaturated double bond, the elastic modulus is lowered, but the glass transition point is also considerably lowered (Japanese Patent Laid-Open No. 58-174416).
No. 60-8315).

In recent years, an epoxy resin composition containing silicone oil has been reported as a stress-reducing material having improved heat resistance and moisture resistance. However, bleeding of silicone oil onto the molded product, contamination of the mold, LSI and VLSI
The fine dispersion of silicone oil or rubber particles required in JP-A-54-54168 has not been achieved (JP-A-54-54168).
No.), a resin composition sufficiently using silicone has not been reported.

The object of the present invention is to provide a specific organopolysiloxane,
By reacting both end carboxyl group-containing butadiene-acrylonitrile copolymer and dispersing it in the epoxy resin, the elastic modulus is greatly reduced without lowering the glass transition temperature, and the heat shock resistance is remarkably improved. Another object is to provide an epoxy resin composition.

[Means for Solving the Problem] As a result of intensive studies to achieve the above object, (1) a) epoxy resin b) phenolic resin curing agent c) organopolysiloxane having two or more epoxy groups in the molecule intramolecular An organopolysiloxane having two or more epoxy groups and a polyoxyalkylene group, a butadiene-acrylonitrile copolymer having carboxyl groups at both ends, and an intramolecular epoxy equivalent (a) and a carboxyl group equivalent (b). Epoxy resin composition for semiconductor encapsulation comprising a butadiene-acrylonitrile copolymer-modified organopolysiloxane obtained by reacting in a ratio (b / a) of 0.05 to 0.5, (2) above, c), Organopolysiloxane,
The epoxy resin composition for semiconductor encapsulation according to the above item (1), which comprises a butadiene-acrylonitrile copolymer-modified organopolysiloxane obtained by reacting a butadiene-acrylonitrile copolymer in the above-mentioned b) phenolic resin curing agent. The object of the present invention has been achieved by

The a) epoxy resin used in the present invention is not particularly limited, and generally known polyfunctional epoxy compounds,
For example, novolac type epoxy resin, bisphenol A
Examples thereof include type epoxy resin, alicyclic epoxy resin, glycidyl ester epoxy resin, and linear aliphatic epoxy resin. The epoxy resin may be used alone,
Also, two or more kinds of mixed systems may be used. Among the above epoxy resins, a novolac type epoxy resin is preferable from the viewpoint of electrical characteristics and heat resistance. Examples of novolac type epoxy resins include cresol novolac type epoxy resins and phenol novolac type epoxy resins.

The preferred epoxy equivalent and softening point of the epoxy resin are appropriately selected according to the type of epoxy resin. For example, as the novolac type epoxy resin, one having an epoxy equivalent of 160 to 250 and a softening point of 50 to 130 ° C. is usually used. Furthermore, in the cresol novolac type epoxy resin, an epoxy equivalent of 150 to 210 and a softening point of 60 to 110 ° C. are preferable, and in the phenol novolac type epoxy resin,
An epoxy equivalent of 160 to 250 and a softening point of 60 to 110 ° C are preferable.

b) As a phenol resin curing agent, phenol, 0-
Cresol, m-cresol, p-cresol, ethylphenol, xylenols, p-tert-butylphenol,
Examples thereof include resins obtained by reacting at least one phenol compound selected from alkyl-substituted phenols such as octylphenol and nonylphenol with formaldehyde.

The organopolysiloxane of c) is one having two or more epoxy groups in the molecule and having a viscosity of 1 to 500,000 centistokes. For example, SF8411, SF8413, BY16-855 manufactured by Toray Silicone, KF100T manufactured by Shin-Etsu Chemical,
Examples include KF102 and TSF4730 manufactured by Toshiba Silicone.

The organopolysiloxane of c) has two or more epoxy groups in the molecule, and further contains 10 to 80% by weight of polyoxyethylene, polyoxypropylene, or a polyoxyalkylene group which is a copolymer thereof. It has a viscosity of 1 to 500,000 centistokes.
For example, SF8421, BX16-863, BX1 manufactured by Torre Silicone
6-864, BX16-866 and the like.

The mixing ratio of the organopolysiloxane of, is in the range of 0.1 to 10 by weight ratio (/).

butadiene having both terminal carboxyl groups of c)
The acrylonitrile copolymer has a molecular weight of 1,000 to 5,000 and contains 5 to 30% by weight of acrylonitrile. For example, Hiker CTBN1300 × 8 manufactured by Ube Industries,
1300 × 13 and so on.

Ratio of epoxy group equivalent (a) to carboxyl group equivalent (b) of organopolysiloxane (b / a)
Is in the range of 0.05 to 0.5, the production of butadiene-acrylonitrile copolymer modified organopolysiloxane,
It can be carried out with or without a solvent. When a solvent is used, it is preferable to use a solvent in which c), and can be dissolved well with each other, such as methyl ethyl ketone and melisobutyl ketone. In order to accelerate the reaction, it is preferable to use a catalyst such as triphenylphosphine, 2-ethyl-4-methylimidazole. The reaction is preferably carried out at 120 to 180 ° C. for 2 to 10 hours with vigorous stirring.

In addition, these reactions were carried out in phenol resin at 120 to 1
By carrying out at 80 ° C for 2 to 10 hours, the epoxy group of the organopolysiloxane reacts with the hydroxyl group of the phenol resin at the interface between the organopolysiloxane particles and the phenol resin, and the particle interface is stabilized and the dispersibility is improved. To do.

In the present invention, in addition to the above essential components, various compounding agents such as imidazoles, tertiary amines,
Curing accelerators such as organic phosphines and diazavin chloroalkenes, dissolved silica, crystalline silica, inorganic fillers such as calcium carbonate, coupling agents such as epoxysilane, aminosilane, alkyl titanate, natural wax, synthetic wax, etc. A release agent, a flame retardant such as antimony trioxide and antimony pentoxide, and a coloring agent such as carbon black may be added.

In the present invention, the production of the composition is not particularly limited, but, for example, components a) to c) and other components are blended, mixed with a Henschel mixer or the like, and then 70 to 110 ° C by a roll, a kneader or the like. By kneading with, it is possible to obtain the desired epoxy resin composition having excellent properties.

[Examples of the Invention] Table 1 shows materials used in Examples and Comparative Examples, and compounding amounts (parts by weight).

(1) Epoxy resin (I) Orthocresol novolac type epoxy resin (epoxy equivalent 197, softening point 73 ° C) (II) Brominated phenol novolac type epoxy resin (epoxy equivalent 275, softening point 84 ° C) (2) Phenolic resin softening Agent Phenol novolac resin (hydroxyl group equivalent 108, softening point 96
(3) Organopolysiloxane c) epoxy equivalent 3000, viscosity 8000 centistokes c) epoxy equivalent 7000, polyoxyalkylene group content 70% by weight, viscosity 3500 centistokes (4) c) both end carboxyl groups With butadiene-acrylonitrile copolymer having a carboxyl group equivalent of 1900 and acrylonitrile content of 17
%, Number average molecular weight 3900 (hereinafter abbreviated as CTBN) (5) Curing accelerator triphenylphosphine (6) Filler dissolved silica (7) Release agent carnauba wax (8) Coupling agent γ-glycidoxypropyl Trimethoxysilane (9) Flame retardant aid Antimony trioxide (10) Colorant Carbon black Examples 1 to 3 (modification of organopolysiloxane with CTBN), 80 and 20 parts by weight of organopolysiloxane, respectively, butadiene-acrylonitrile 10 parts by weight of the copolymer and 1 part by weight of triphenylphosphine as a catalyst were dissolved in 400 parts by weight of methyl isobutyl ketone and reacted in an autoclave at 150 ° C. for 3 hours with vigorous stirring. After the reaction, the solvent was removed by vacuum distillation,
A butadiene-acrylonitrile copolymer modified organopolysiloxane was prepared.

The modified organopolysiloxane obtained by the above operation is mixed with the materials shown in Table 1, such as epoxy resin and phenol resin curing agent, kneaded with a heating roll, cooled, and then pulverized to prepare an epoxy resin molding material. did. Test pieces were prepared from these molding materials under molding conditions of 175 ° C. × 3 minutes, post-cured at 175 ° C. × 6 hours, and various properties were evaluated. The results are shown in Table 2.

70 g of the organopolysiloxane of Example 4, 30
g, butadiene-acrylonitrile copolymer 20 g, and triphenylphosphine 1 g as a catalyst were added to phenol novolac resin 163 g heated and melted at 150 ° C., and the mixture was reacted for 3 hours with vigorous stirring to obtain a butadiene-acrylonitrile copolymer-modified organopolyene. A phenol resin in which siloxane was dispersed in the form of particles was produced.

The modified organopolysiloxane-containing phenol resin curing agent obtained by the above operation was mixed with the materials shown in Table 1, and the same operation as in Examples 1 to 3 was performed. The results of evaluation of various properties are shown in Table 2.

Comparative Examples 1-2 The materials shown in Table 1 were mixed and the same operation as in Examples 1-3 was performed. The results of evaluation of various properties are shown in Table 2.

[Effects of the Invention] The epoxy resin composition of the present invention has a glass transition temperature maintained, low elasticity, and significantly improved heat shock resistance. Further, the butadiene-acrylonitrile copolymer-modified organopolysiloxane is finely dispersed in the epoxy resin and is well compatible at the interface with the resin, so that the modified organopolysiloxane particles are stabilized, and the surface of the molded product during molding is also improved. Bleeding to the lead frame is significantly reduced, and the adhesion between the lead frame and the resin is improved.

[Brief description of drawings]

The figure shows a test piece used for measuring the physical properties of the present invention. First
The figure is a cross-sectional view of a test piece prepared for measurement of heat shock resistance. FIG. 2 is a test piece prepared for measuring the penetration of a fluorescent liquid, (a) is a plan view and (b) is a front view. 1 ... Epoxy resin composition, 2 ... Washer, 3 ... 42 Alloy frame.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location H01L 23/29 H01L 23/30 R 23/31 (56) References JP-A-63-199218 (JP , A) JP 63-295623 (JP, A) JP 61-111320 (JP, A) JP 60-206824 (JP, A)

Claims (2)

(57) [Claims] 1. a) Epoxy resin b) Phenol resin curing agent c) Organopolysiloxane having two or more epoxy groups in the molecule Organopolysiloxane having two or more epoxy groups and a polyoxyalkylene group in the molecule. A butadiene-acrylonitrile copolymer having carboxyl groups at both ends was obtained by reacting and with the ratio (b / a) of the intramolecular epoxy equivalent (a) to the carboxyl group equivalent (b) of 0.05 to 0.5. An epoxy resin composition for semiconductor encapsulation, which comprises a butadiene-acrylonitrile copolymer-modified organopolysiloxane. 2. A butadiene-acrylonitrile copolymer-modified organopolysiloxane obtained by reacting the organopolysiloxane of c), and the butadiene-acrylonitrile copolymer in the b) phenolic resin curing agent. The epoxy resin composition for semiconductor encapsulation according to claim 1, wherein: