JPH04198211A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition for semiconductor sealing excellent in heat shock resistance, soldering-heat resistance, low viscosity and moldability by mixing a diepoxy compound with a diphenol compound, a polyepoxy compound, a cure accelerator, and an inorganic filler. CONSTITUTION:A resin composition essentially consisting of a diepoxy compound (A) having two epoxy groups in the molecule, a diphenol compound (B) having two phenolic hydroxyl groups in the molecule, a polyepoxy compound (C) having at least three epoxy groups in the molecule, a cure accelerator (D) and an inorganic filler (E). The mixing ratio between component A and component C is such that C/(A+C)=25-75wt.%. As component D, any cure accelerator that can accelerate a reaction between epoxy and phenolic hydroxyl can be used, and one generally used in a sealing material can be extensively used. As component E, crystalline silica or fused silica is particularly desirable.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an epoxy resin composition with excellent thermal shock resistance, soldering heat resistance, and low viscosity, which is suitable for a resin composition for sealing high-density ICs. .

[Conventional technology]

Traditionally, electronic components such as diodes, transnostars, and integrated circuits have been sealed with thermosetting resins, or, especially for integrated circuits, 0-cresol novolac-epochene resin, which has excellent heat resistance and moisture resistance, has been cured with novolac-type phenolic resin. Evokin resin is used.

However, in recent years, as integrated circuits have become more highly integrated, chips have become larger and larger, and packages have changed from the conventional DIP type to surface-mounted smaller, thinner flat packages.
5OPSSOJ is changing to PLCC.

That is, when a large chip is enclosed in a small and thin package, problems such as the occurrence of cracks due to stress and a decrease in moisture resistance due to these cracks are attracting attention.

In particular, there is a need for a sealing resin that meets two requirements: thermal shock resistance and soldering heat resistance.

In order to improve thermal shock resistance, silicone compounds such as silicone oil and silicone rubber, and synthetic rubbers have been added. However, since these additions cause inconvenient phenomena such as mold staining during molding and generation of resin flakes, silicone-modified resins have been developed in which silicone is reacted with epoxy resins or curing agents. (For example, JP-A-58-
21417). Current sealing resins have considerably improved thermal shock resistance through the use of this technology. However, these methods either introduce a low elastic modulus domain into the matrix resin to lower the overall elastic modulus, or there is a problem with the adhesion between the domain and the matrix, resulting in a decrease in elastic modulus and strength. It is still insufficient, and the soldering heat resistance tends to decrease, which is a problem. Therefore,
It becomes necessary to improve the thermal shock resistance of the matrix resin itself without adding the above-mentioned low stress imparting agent.

To improve soldering heat resistance, we investigated polyimide resins and fillers, and utilized trifunctional resins (e.g.,
16862Cj Publication) is considered promising, but both have poor thermal shock resistance and are prone to defects such as die pad shift due to increased resin composition viscosity. Composition systems are difficult to obtain.

Therefore, it is thought that an effective method is to freely change the compositional structure such as the distance between crosslinking points and the main chain structure of the resin to balance various physical properties while improving the soldering heat resistance.

[Invention or problem to be solved]

The object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that has excellent thermal shock resistance, soldering heat resistance, low viscosity, and moldability.

[Means to solve the problem]

The present inventors conducted extensive research to solve these problems and discovered a resin composition having the following composition.

(A) Bifunctional phenolic compound containing two epoxy groups in the molecule (B) Bifunctional phenol compound containing two phenolic hydroxyl groups in the molecule (C) Containing three or more epoxy groups in the molecule A polyfunctional Evoquin compound containing (D) a curing accelerator and (E) an inorganic filler as essential components, and a blending ratio of (B) and (C) or (C)/
By using a composition in which (B) + (C) = 25 to 75% by weight, thermal shock resistance, soldering heat resistance, low viscosity,
Furthermore, the present invention was completed by discovering that a resin composition for semiconductor encapsulation having excellent moldability can be obtained.

[For production]

The bifunctional poxy compounds containing two epoxy groups in the molecule used in the present invention include bifunctional phenolic compounds such as 4,4'-dihydroquine diphenylmethane, 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylpropane, and
4'-dibiphenol, 3.3', 5.5'-tetramethyl-4,4'-dibiphenol, 1,6-cyhydroquinaphthalene, cyclohexylidenehisphenol A,
3.3'-diallyl-4,4'-nohytroquinemethane,
In addition to diglyndyl ethers of catechol, resolnones, hydroquinone, etc., brominated hisphenol A type epochine resins and alicyclic epochino compounds may be mentioned.

These materials may be used alone or in combination of two or more.

Bifunctional phenolic compounds containing two phenolic hydroxyl groups in the molecule include, in addition to the above-mentioned phenolic compounds, monomers or oligomers containing one phenolic hydroxyl group and aldehydes such as formaldehyde or salicylaldehyde, or Examples include cocondensates prepared by adding compounds having various aromatic rings or alicyclic rings as necessary and adjusting the charging ratio and reaction conditions so that only two phenolic hydroxyl groups are contained in the molecule. These materials may be used alone or in combination of two or more.

These difunctional epoxy compounds and difunctional phenol compounds often exhibit a low viscosity of several centimeters at the molding temperature (165 to 185°C), and are capable of significantly lowering the viscosity of the resin composition. It provides high fluidity during molding, and also provides high wettability and high adhesion at the interface between the lead frame, chip, and island in IC panocheno, improving solder crack resistance. In addition, since it is possible to significantly increase the content of inorganic fillers, the heat strength and
Thermal shock resistance and solder crack resistance are further improved.

Examples of the polyfunctional epoxy compound containing three or more epoxy groups in the molecule used in the present invention include polyfunctional phenolic compounds such as phenol novolac, orthocresol novolac, and tris(vitroquine alkylphenyl)methane. Monomers or oligomers having a phenolic hydroxyl group, cocondensates made by reacting the bifunctional phenol compound described above with aldehydes such as formaldehyde or salicylaldehyde, or, if necessary, with compounds having various aromatic rings or alialicyclic rings. and polyfunctional alicyclic epoxy compounds.

These compounds may be used alone or in combination of two or more.

This polyfunctional epoxy compound is a difunctional poquin compound, 2
It brings about three-dimensional crosslinking with a functional phenolic compound.

With bifunctional epoxy compounds/phenol compounds, only linear polymers are produced in normal reactions, or by adding polyfunctional epoxy compounds, crosslinking points are generated three-dimensionally to form thermosetting polymers. generate. Furthermore, by adjusting the blending amount of this polyfunctional phenolic compound, it is possible to freely adjust the curing characteristics, crosslinking density, and distance between crosslinking points, and it is possible to freely adjust the curing characteristics, crosslinking density, and distance between crosslinking points. Cured product properties can be adjusted as desired.

The blending ratio of these polyfunctional epoxy compounds is (polyfunctional epoxy compound)/(bifunctional polyfunctional epoxy compound ÷ polyfunctional epoxy compound), which is 25 to 75% by weight, which is appropriate.If it is less than 25% by weight, the curability will be significantly inferior. Also, various physical properties when heated are greatly reduced. If it exceeds 75% by weight, the effect of extending the distance between crosslinking points will decrease, and the effect of lowering elasticity and increasing toughness will not be obtained, which is not preferable.

The mixing ratio of the epoxy compound and the phenol compound is preferably in the range of 0.7 to 1.3 in terms of equivalent ratio.

Inorganic fillers used in the present invention include crystalline silica,
Examples include fused silica, alumina, calcium carbonate, talc, mica, glass fiber, etc., and these may be used alone or in combination of two or more. Among these, crystalline silica or fused silica is particularly preferably used.

Further, the curing accelerator used in the present invention only needs to be one that promotes the reaction between the Epoquine group and the phenolic hydroxyl group.
A wide range of materials commonly used for sealing can be used, such as tertiary amines such as BDM 8, imidazoles, 1,8-diazabicyclo[5,4,0]undecene-7, Organic phosphorus compounds such as phenylphosphine can be used alone or in combination of two or more.

If necessary, mold release agents such as waxes, hexabromo pentene, decabromo biphenyl ether, antimony trioxide, etc. #Fuel agent, coloring agent such as carbon black, red iron oxide, silane coupling agent, geothermal plastic resin, etc. may be added and blended as appropriate.

The general method for producing the epoxy resin composition for semiconductor encapsulation of the present invention is to thoroughly mix raw materials in a predetermined blending ratio using a mixer, etc., and then further mix them using a roll or kneader.
It can be easily produced by carrying out a melt mixing treatment using a method such as the above, followed by cooling and solidifying the powder and pulverizing it to an appropriate size.

〔Example〕

The present invention will be illustrated below with examples.

Examples 1-6. Comparative Example 1.2 The compositions having the respective compounding ratios shown in Table 1 were thoroughly mixed at room temperature, further kneaded at 95 to 100°C with a twin-screw roll, cooled and crushed to obtain a molding material. was tableted to obtain an epoxy resin composition for semiconductor encapsulation.

This material was molded using a transfer molding machine (molding conditions: 2 mold temperatures: 175° C., 1 curing time: 2 minutes), and the resulting molded products were post-cured at 175° C. for 8 hours and evaluated. The results are shown in Table 1.

Evaluation method *1. Length of a molded product when 20 g of sample was molded using a spiral flow measurement mold according to Spiral Flow FMM4-1-66 at a molding temperature of 175°C, a molding pressure cuff of 0 MPa, and a molding time of 2 minutes.

*2. Koka type flow viscosity Koka type flow viscosity at 175℃ (voids) *3. Thermal shock resistance test molded product (chip size 36InIn2, package thickness 2
．． A temperature cycle test (+150°C to -196°C) was performed on 20 pieces of 05 mm 1 post-cured 175°Cl8Hrs), and the number of cracks generated after 500 cycles was shown.

*4. Solder heat resistance test molded product (chip size 36tun2, package thickness 2.
After treating 20 molded products under steam at 85°C and 85% RH for 72 hours, they were immersed in a solder bath at 240°C for 10 seconds, and the number of molded products with cracks is shown.

*5. hardness Molded at 175°C and measured 10 seconds after release from the mold.

〔Effect of the invention〕

The semiconductor encapsulating resin composition of the present invention, which contains a bifunctional poxy compound, a bifunctional phenolic compound, a polyfunctional evoquin compound, an inorganic filler, and a curing accelerator as essential components, has extremely excellent thermal shock resistance and soldering heat resistance. , has low viscosity, has excellent gold wire deformability and filling properties, and is also excellent in molding processability (resin processing), and is an extremely well-balanced resin composition, making it an excellent resin for high-integration IC encapsulation. The composition is extremely reliable.

Claims (1)

[Claims] (1) (A) Bifunctional epoxy compound containing two epoxy groups in the molecule (B) Bifunctional phenolic compound containing two phenolic hydroxyl groups in the molecule (C) Three epoxy groups in the molecule The polyfunctional epoxy compound containing the above (D) curing accelerator and (E) inorganic filler are essential components, and the blending ratio of (A) and (C) is (C)/
An epoxy resin composition for semiconductor encapsulation, characterized in that (A)+(C)=25 to 75% by weight.