JP3339772B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation having excellent flame retardancy.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits have been sealed with an epoxy resin composition. In this composition, a halogen-based flame retardant alone or a combination of a halogen-based flame retardant and antimony trioxide is used as a flame retardant, and an inorganic filler such as fused silica or crystalline silica is blended as a filler. However, from the viewpoint of environmental hygiene, a flame-retardant epoxy resin composition that does not use a halogen-based flame retardant or antimony trioxide is required. In response to this requirement, metal hydroxides such as aluminum hydroxide and magnesium hydroxide have been studied, but they have not been put to practical use because their effects cannot be exhibited unless they are added in large amounts and in large amounts.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a flame-retardant epoxy resin composition for semiconductor encapsulation containing no antimony and halogen by using zinc borate. There.

[0004]

SUMMARY OF THE INVENTION The present invention provides a semiconductor encapsulation comprising (A) an epoxy resin, (B) a phenolic resin curing agent, (C) a curing accelerator, (D) zinc borate, and (E) an inorganic filler. Epoxy resin composition for use.

[0005] Zinc borate used in the present invention is 4ZnO.B ₂ O ₃ .H ₂ O or 2Zn because of its balance between flame retardancy and moisture resistance.
_{O · 3B 2 O 3 · 3.5H} 2 O is _{preferred, 4ZnO · B 2 O 3 ·} H 2 O from consideration of the formability is more preferable.
This zinc borate is readily available from the market. Although it depends on the content of the inorganic filler, zinc borate is preferably contained in the entire composition at 1 to 20% by weight. 1
When the amount is less than 20% by weight, the flame retardancy is insufficient, and when the amount is more than 20% by weight, the moisture resistance and the moldability deteriorate.

[0006] The epoxy resin used in the present invention is a monomer or oligomer having two or more epoxy groups in one molecule,
It refers to polymers in general, and its molecular weight and molecular structure are not particularly limited. For example, biphenyl type epoxy compounds, bisphenol type epoxy compounds, phenol novolak type epoxy resins, cresol novolak type epoxy resins, triphenol methane type epoxy compounds, alkyl compounds Examples include a modified triphenolmethane-type epoxy compound and a triazine nucleus-containing epoxy resin, which may be used alone or in combination.

The phenolic resin curing agent used in the present invention comprises:
Although its molecular weight and molecular structure are not particularly limited,
For example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin, paraxylylene-modified phenol resin, terpene-modified phenol resin, triphenolmethane compound, and the like,
In particular, a phenol novolak resin, a dicyclopentadiene-modified phenol resin, a paraxylylene-modified phenol resin, a terpene-modified phenol resin and the like are preferable, and they may be used alone or in combination. Further, as a blending amount of these curing agents, the ratio of the number of epoxy groups of the epoxy compound to the number of hydroxyl groups of the phenol resin curing agent is preferably 0.8 to 1.2.

The curing accelerator used in the present invention may be any one which promotes a curing reaction between an epoxy group and a hydroxyl group.
What is generally used for a sealing material can be widely used. For example, 1,8-diazabicycloundecene, triphenylphosphine, benzyldimethylamine, 2-methylimidazole and the like can be mentioned, and they can be used alone or in combination. Examples of the inorganic filler include a fused silica powder, a crystalline silica powder, alumina, silicon nitride and the like, and a fused silica powder and a crystalline silica powder are preferable in view of a difference in a thermal expansion coefficient from a lead frame or the like and an impurity amount. The amount of the inorganic filler is preferably 50 to 95% by weight in the whole composition in view of the balance between moldability and reliability. Further, from the viewpoint of fluidity and filling properties, the inorganic filler has an average particle size of 10 to 20 μm, a particle size of 10 μm or less including 20 to 45% by weight, and a particle size of 70 μm or more having a particle size of 10% by weight or less. Those having a distribution are preferred. In particular, in a composition having a large amount of filler, spherical fused silica is generally used.

The epoxy resin composition of the present invention comprises an epoxy resin, a phenolic resin curing agent, a curing accelerator, zinc borate and an inorganic filler as essential components. In addition to this, a silane coupling agent, carbon black And various additives such as a releasing agent such as natural wax and synthetic wax, and a low stress additive such as silicone oil and rubber. Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, each of the essential components and other additives are mixed with a mixer.
After sufficiently mixing the mixture, the mixture is melted and kneaded with a hot roll or a kneader, cooled, and pulverized to obtain a sealing material. These molding materials can be applied to coating, insulation, sealing, and the like of transistors and integrated circuits, which are electric or electronic components.

[0010]

The present invention will be specifically described below with reference to examples. << Examples 1 to 5, Comparative Examples 1 to 5 >> The compositions shown in Tables 1 and 2 were mixed at room temperature with a mixer, and mixed at 70 to 100 ° C.
The mixture was kneaded by a shaft roll, cooled and pulverized to obtain a molding material. Further, the obtained molding material was tableted, and was subjected to low pressure transfer molding at 175 ° C., 70 kg / cm ² , 120 kg.
Under the condition of seconds, a test piece for a flame resistance test was molded, and a chip of 3 mm × 3.5 mm was sealed in 16 pDIP for a moisture resistance test. The following moisture resistance test was performed on the sealed test element. The test results are shown in Tables 1 and 2.

The raw materials used are as follows. Orthocresol novolak epoxy resin: softening point 65 ° C, epoxy equivalent 200 g / eq Biphenyl epoxy resin: melting point 110 ° C, epoxy equivalent 195 g / eq Brominated epoxy resin: softening point 60 ° C, epoxy equivalent 360 g Phenol novolak resin curing agent: softening point 80 ° C, hydroxyl equivalent 104 g / eq fused silica powder: average particle size 15 μm, specific surface area 2.2 m
² / g, particle size 10 μm or less 35% by weight, particle size 70 μm or more 8% by weight Spherical silica: average particle size 17 μm, specific surface area 5.0 m ² / g
35% by weight with particle size of 10 μm or less, particle size of 70 μm or more with 6
Wt% triphenylphosphine Ka - carbon black, carnauba wax, zinc borate _{(4ZnO · B 2 O 3 ·} H 2 O) · zinc borate _{(2ZnO · 3B 2 O 3 ·} 3.5H 2 O) · antimony trioxide

The evaluation method is as follows. << Spiral flow >> Mold temperature 175 ℃, pressure 70kg /
It was measured in cm ² . << flammability test >> UL-94 vertical test (sample thickness 1.0m
m), represented by flame retardancy. << Moisture Resistance Test >> The sealed test element was subjected to a pressure cooker test (125 ° C., 100% RH), and the open defect of the circuit was measured and expressed as a failure occurrence time. << Moldability >> Using a low-pressure transfer molding machine, the curing time (second) at which 16 pDIP can be molded under the conditions of a mold temperature of 175 ° C. and a pressure of 70 kg / cm ² was defined as moldability.

Table 1 Example 1 2 3 4 5 blend (parts by weight) Orthocreso-Lenopenac type epoxy resin 18.3 18.3 18.3 8.6 Biphenyl type epoxy resin 4.4 Phenol novolak resin 9.5 9.5 9.5 4.5 2.3 Fused silica powder 61.0 51.0 51.0 Spherical silica 84.5 91.0 Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 Carbon black 0.5 0.5 0.5 0.5 0.5 Carnauba wax 0.5 0.5 0.5 0.5 0.5 4ZnO ・ B ₂ O ₃・ H ₂ O 10.0 20.0 3.0 1.1 2ZnO ・ 3B ₂ O ₃・ 3.5H ₂ O 20.0 Physical properties Spiral flow ( cm) 100 100 100 60 70 Flame retardancy V-0 V-0 V-0 V-0 V-0 Moisture resistance (Hr) 400 350 350 400 400 Moldability (curing time: seconds) 90 120 200 90 90

Table 2 Comparative Example 1 2 3 4 5 Blended (parts by weight) Orthocreso-Lenopenac type epoxy resin 18.3 16.6 7.8 Biphenyl type epoxy resin 4.4 4.3 Brominated epoxy resin 2.0 1.0 0.5 Phenol novolak resin 9.5 2.3 9.2 4.3 2.5 Fused silica powder 41.0 69.0 Spherical silica 91.3 84.7 91.0 Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 Carbon black 0.5 0.5 0.5 0.5 0.5 Carnauba wax 0.5 0.5 0.5 0.5 0.5 4 ZnO ・ B ₂ O ₃・ H ₂ O 30.0 0.8 Antimony trioxide 2.0 1.0 0.5 Physical properties Spiral flow (cm ) 130 70 100 60 70 Flame retardant V-0 V-1 V-0 V-0 V-0 Moisture resistance (Hr) 100 400 300 400 400 Moldability (curing time: seconds) 300 90 90 90 90

[0015]

As described above, by encapsulating a semiconductor element with the composition of the present invention, a semiconductor device containing no halogen-based flame retardant and antimony trioxide and having excellent moisture resistance and flame retardancy can be obtained.

Claims (2)

(57) [Claims] 1. An epoxy resin composition comprising (A) an epoxy resin, (B) a phenolic resin curing agent, (C) a curing accelerator, (D) zinc borate, and (E) an inorganic filler .
When the content of the zinc borate in the composition is 1 to 20% by weight.
And the content of the inorganic filler is 50 to 95% by weight.
An epoxy resin composition for semiconductor encapsulation , wherein the composition does not contain antimony and halogen . 2. The structure of zinc borate is 4ZnO.B ₂ O ₃
· H ₂ O in a claim 1 semiconductor encapsulating epoxy resin composition.