JP2001261936A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition that generates no coagulation of fine silica particles even when a silane coupling agent of high reactivity is used. SOLUTION: The objective epoxy resin composition for sealing semiconductors characteristically comprises, as essential components, (A) an epoxy resin, (B) a hardening accelerator, (D) an inorganic filler, (E) a surface- treated silica in which 100 pts.wt. of silica is surface-treated with 1-5 pts.wt. of silane coupling agent, at least one or more selected from the group consisting of γ-aminopropyltriethoxylsilane, γ-aminopropyltrimethoxysilane, γ- glycidylpropyltriethoxysilane and γ-glycidylpropyltrimethoxysilane wherein the total of (D)+(E) is 60-90 wt.% based on the whole epoxy resin composition and the weight ratio of (D)/(E) is 60/40-90/10.

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 without aggregation of fine silica particles and a semiconductor device.

[0002]

2. Description of the Related Art As a semiconductor encapsulating material, an epoxy resin composition has been mainly used from the viewpoint of characteristics, productivity, price, etc., and silica as a main component thereof is uniformly mixed with a silane coupling agent. What has been processed has been used a lot. Surface treatment of silica improves adhesion at the interface between silica and the resin component, improves adhesion between the resin component and the semiconductor element or lead frame, further improves the dispersibility of silica in the resin component, and is favorable. To obtain high fluidity. In the conventional method for producing an epoxy resin composition, the entire amount of silica used in terms of uniform treatment has been treated with a silane coupling agent. However, various semiconductor devices have been developed in response to recent mounting forms of various semiconductor devices,
In epoxy resin compositions applied to these advanced semiconductor devices, silicas having various particle size distributions have been used in response to demands for better moldability and reliability. In order to obtain excellent moldability and reliability, it is necessary to further fill the silica more than the conventional amount of silica, so that a large amount of fine silica is added, which causes a problem that silica is easily aggregated. are doing.
In particular, when a surface treatment is performed with a silane coupling agent having excellent reactivity with silica, this aggregation is accelerated, and the inherent characteristics of the fine silica may not be exhibited due to the aggregation, which is a problem.

[0003]

The present invention solves such a problem by increasing the amount of a silane coupling agent to be treated with respect to silica more than usual and blending a small amount of surface-treated silica. It is intended to provide an epoxy resin composition free from aggregation of fine silica due to use of a silane coupling agent and a semiconductor device using the same.

[0004]

The present invention provides (A) an epoxy resin, (B) a phenolic resin, (C) a curing accelerator,
100 parts by weight of (D) an inorganic filler and (E) silica is γ
-Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidylpropyltriethoxysilane, at least one or more silane coupling agents selected from the group of γ-glycidylpropyltrimethoxysilane in an amount of 1 to 5 parts by weight. An epoxy resin composition containing silica that has been surface-treated using as an essential component,
The total amount of (D) + (E) is 6 in the total epoxy resin composition.
0 to 90% by weight, and the weight ratio of (D) / (E) is 60/4
An epoxy resin composition for encapsulating a semiconductor, which is 0 to 90/10, and a semiconductor device obtained by encapsulating a semiconductor element using the epoxy resin composition.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is:
Monomers, oligomers and polymers generally having two or more epoxy groups in one molecule, such as biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, phenol novolak type epoxy Resin, cresol novolak type epoxy resin, naphthalene type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin and triazine nucleus containing epoxy resin, and these may be used alone or in combination. Absent. Particularly, a cresol novolak type epoxy resin is preferable from the viewpoint of moldability and reliability.

The phenolic resin used in the present invention includes:
For example, phenol novolak resin, cresol novolak resin, dicyclopentadiene-modified phenol resin,
Examples thereof include phenol aralkyl resins, terpene-modified phenol resins, and triphenol methane resins, which may be used alone or as a mixture. Particularly, a phenol novolak resin is preferable from the viewpoint of moldability. Further, by setting the ratio (a) / (b) of the number of epoxy groups (a) of the epoxy resin to the number of phenolic hydroxyl groups (b) of the phenol resin to be 0.8 to 1.2, the resulting resin composition can be cured. The glass transition temperature of the product becomes 100 to 200 ° C., and a desired glass transition temperature is obtained.

As the curing accelerator used in the present invention, any one can be used as long as it accelerates the curing reaction between the epoxy group and the phenolic hydroxyl group, and those generally used for a sealing material can be used. For example, 1,8-diazabicyclo (5,4,0) undecene-7, tertiary amines,
Examples thereof include phosphonium salts such as triphenylphosphine and tetraphenylphosphonium / tetraphenylborate, benzyldimethylamine, 2-methylimidazole and the like, and these may be used alone or in combination.

As the inorganic filler used in the present invention, for example, fused silica, fused spherical silica, crystalline silica, alumina, aluminum nitride, silicon nitride and the like can be mentioned, but from the viewpoint of fluidity, reliability and cost. Pulverized silica and spherical fused silica are preferred. Maximum particle size of inorganic filler is 200μ
m or less, more preferably 150 μm or less, and the average particle size is preferably 8 to 30 μm. Examples of the silica that has been surface-treated with a silane coupling agent in advance include fused silica, fused spherical silica, synthetic spherical silica, and crystalline silica. These may be used alone or as a mixture. The maximum particle size of these silicas is 20
It is preferably at most 0 μm, more preferably at most 150 μm. The average particle size may be from 8 to 30 μm, and if it is less than 8 μm, there is a problem of aggregation, and if it exceeds 30 μm, there is a problem of thin burrs, which is not preferable. Examples of the silane coupling agent used for the surface treatment include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-glycidylpropyltriethoxysilane, and γ-glycidylpropyl, which have excellent reactivity with silica at room temperature. Trimethoxysilane is preferred, and these may be used alone or as a mixture. The ratio of silica previously treated with a silane coupling agent and the silane coupling agent is preferably 1 to 5 parts by weight as the silane coupling agent with respect to 100 parts by weight of silica. 1 silane coupling agent
If the amount is out of the range of 5 to 5 parts by weight, it is not preferable from the viewpoints of a decrease in adhesion between the inorganic filler and the resin component, a decrease in fluidity and the generation of silica aggregates.

As a method of treating the surface of silica with a silane coupling agent, silica is charged into a super mixer, a ball mill, a vibratory mixer or the like, and after the silane coupling agent is added, the silica is uniformly mixed. During or after mixing, heat treatment may be performed at 100 to 130 ° C. for 2 to 12 hours as needed. After taking out the treated silica from the mixing vessel,
If necessary, by passing through a 100-300 μm sieve,
Silica previously treated with a silane coupling agent can be obtained. The silica (E) treated with the inorganic filler (D) and the silane coupling agent has a total amount of (D) + (E) of 60 to 90% by weight in the total epoxy resin composition, and 60% by weight. If it is less than 10%, the resin component increases, so that the water absorption rate increases and the moisture resistance deteriorates. On the other hand, if the content is more than 90% by weight, the fluidity is remarkably inferior. The weight ratio of (D) / (E) is from 60/40 to 90/10. If the weight ratio of (D) is less than 60, the amount of silica previously treated with a silane coupling agent increases, which may undesirably cause a problem of aggregation. If it exceeds 90, on the contrary, the amount of silica previously treated with the coupling agent decreases, and its effect decreases, which is not preferable. If the weight ratio of (E) is less than 10, the adhesiveness to the resin will decrease, and if it exceeds 40, the fluidity of the epoxy resin composition will decrease, which is not preferable.

The epoxy resin composition of the present invention comprises (A)
In addition to the component (E), if necessary, a flame retardant such as a brominated epoxy resin, antimony oxide, or a phosphorus compound, a coloring agent such as carbon black, a low-stress component such as silicone oil, silicone rubber, or synthetic rubber. wax,
Various additives such as release agents such as higher fatty acids and metal salts thereof or paraffin, and antioxidants can be blended. Further, a coupling agent other than the silane coupling agent used in the present invention may be blended as required. The epoxy resin composition of the present invention is obtained by mixing the components (A) to (E) and other additives at room temperature using a mixer, kneading them with a kneading machine such as a roll or an extruder, cooling, and pulverizing. can get. In order to mold a desired semiconductor using the epoxy resin composition of the present invention, it is sufficient to cure and mold by a molding method such as transfer molding and injection molding. The molding conditions of the transfer mold include a mold temperature of 160
At 190 ° C., particularly preferably at 175 ° C., at an injection pressure of 70
１４０140 kg / cm ² , an injection time of 5 to 30 seconds, and a curing time of 30 to 150 seconds. The molding conditions of the injection mold are a mold temperature of 160 to 190 ° C., particularly preferably 175 ° C., and a screw temperature of 80 to 120.
C., an injection time of 10 to 30 seconds, and a curing time of 30 to 120 seconds are desirable. After the molding, post-curing may be performed if necessary.

Hereinafter, the present invention will be described specifically with reference to examples. The mixing ratio is by weight. The treated silica used in Examples and Comparative Examples is shown below. Production of Treated Silica Treated Silica 1 Spherical fused silica (average particle size 25 μm, maximum particle size 90 μm) 100 parts by weight γ-aminopropyltriethoxysilane 3 parts by weight are sufficiently mixed by a super mixer, and then dried by a drier.
After heating at 60 ° C. for 6 hours and then passing through a 200 μm sieve to remove aggregates, treated silica 1 was obtained. Treated silica 2 Fused crushed silica (average particle diameter 13 μm, maximum particle diameter 150 μm) 100 parts by weight γ-glycidyltrimethoxysilane 2 parts by weight was sufficiently mixed in a ball mill, and then treated silica 2 was obtained through a 200 μm sieve. Treated silica 3 100 parts by weight of crystalline silica (average particle diameter 25 μm, maximum particle diameter 200 μm) 4 parts by weight of γ-aminopropyltrimethoxysilane were mixed with a supermixer, and the mixture was passed through a 200 μm sieve to obtain treated silica 3. Treated silica 4 Spherical fused silica (average particle size 25 μm, maximum particle size 90 μm) 100 parts by weight γ-aminopropyltrimethoxysilane 0.2 part by weight was sufficiently mixed with a super mixer, and then passed through a 200 μm sieve to remove aggregates. After that, treated silica 4 was obtained. Treated silica 5 Spherical fused silica (average particle diameter 25 μm, maximum particle diameter 90 μm) 100 parts by weight γ-aminopropyltrimethoxysilane 8 parts by weight was sufficiently mixed with a super mixer, and then agglomerates were removed through a 200 μm sieve. Thus, treated silica 5 was obtained.

Example 1 100 parts by weight of fused spherical silica (average particle size: 22 μm, maximum particle size: 75 μm) Treated silica 1 30 parts by weight Methyltrimethoxysilane 0.3 part by weight Orthocresol novolac epoxy resin (softening point: 60 ° C., Epoxy equivalent 198) 17.5 parts by weight Phenol novolak resin (softening point 70 ° C., hydroxyl equivalent 105) 8.1 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0 0.3 parts by weight Brominated epoxy resin (epoxy equivalent 270) 2.1 parts by weight Antimony trioxide 2.1 parts by weight Carbon black 0.5 parts by weight Carnauba wax 0.6 parts by weight The mixture was kneaded 30 times using two rolls at 90 ° C. and 30 ° C., and the obtained kneaded material sheet was cooled and pulverized to obtain a resin composition. It was. The obtained resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Spiral flow: Spy according to EMMI-1-66
Using a mold for Ralflow measurement, mold temperature 175 ° C,
Injection pressure 70kg / cm^TwoThe curing time was measured at 2 minutes.
The unit is cm. With a spiral flow value of 40 cm or less
Was regarded as defective. Coefficient of thermal expansion [α1 (10^-Five/ ° C)] and glass transition temperature
[Tg (° C.)]: tablet the resin composition,
Using a transfer molding machine, mold temperature 175 ° C, injection
Pressure 70kg / cm^TwoThe test piece (15m
m × 4mm × 3mm), and polish at 175 ° C for 8 hours.
I was stoked. Using a thermomechanical analyzer, set the test piece to 0
From 260 ° C to 260 ° C at a heating rate of 5 ° C / min.
Measure the dimensional change due to the rise, linear expansion from the tangent at 25 ° C
The coefficient α1 was determined. Also at the intersection of the tangents at 25 ° C and 240 ° C
Glass transition temperature. Unfilled occurrence rate: gate size is 0.2 × 0.3 mm
80 pin QF with outer dimensions of 14 × 20 × 2.0 mm
P is molded into 50 pieces, and aggregates in the resin composition are clogged in the gate.
The number of unfilled parts generated due to rolling was examined. The molding conditions are
Using a multi-layer molding machine, mold temperature 180 ° C, injection pressure 80k
g / cm ^TwoAnd a curing time of 70 seconds. Adhesive strength: mold temperature 175 ° C, injection pressure 70kg / cm^Two,
 10 mm in molding conditions with a curing time of 2 minutes^TwoCylinder of area
After molding the shaped article on the copper lead frame,
The shear fracture strength was measured with Tensilon.

Examples 2 to 4 and Comparative Examples 1 to 5 The average particle diameter of the fused silica used in Examples 1 to 5 was 1
5 μm, the maximum particle size is 150 μm, the average particle size of the crystalline silica is 25 μm, and the maximum particle size is 150 μm. The melting point of the biphenyl type epoxy resin is 105 ° C. and the epoxy equivalent is 19
In 5, the phenol aralkyl resin has a softening point of 74 ° C. and a hydroxyl equivalent of 175. According to the formulation in Table 1, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results.

[Table 1]

[0015]

According to the present invention, the treatment amount of the silane coupling agent with respect to silica is made larger than usual, and a small amount of the surface-treated silica is blended. An epoxy resin composition free of silica aggregation can be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09K 3/10 C09K 3/10 L Q Z H01L 23/29 H01L 23/30 R 23/31 F term (reference) ) 4H017 AA04 AA22 AA27 AA29 AA39 AB08 AB17 AD06 AE05 4J002 CC042 CC052 CC072 CD041 CD051 CD061 CD071 CD131 DE146 DF016 DJ006 DJ016 DJ017 FB137 FB147 FD016 FD070 FD090 FD130 FD142 FD160 DC05 AD05 DC06 AC05 AF08 DC08 AF05 DC07 FA03 FA04 FA05 FB07 GA04 GA06 JA07 4M109 AA01 BA01 CA21 EB06 EB13 EC20

Claims (2)

[Claims] 1. An epoxy resin, (B) a phenolic resin, (C) a curing accelerator, (D) an inorganic filler, and (E) 100 parts by weight of silica, γ-aminopropyltriethoxysilane, γ- Aminopropyltrimethoxysilane, γ-glycidylpropyltriethoxysilane, γ-
An epoxy resin composition comprising, as an essential component, silica surface-treated using 1 to 5 parts by weight of at least one or more silane coupling agents selected from the group of glycidylpropyltrimethoxysilane, wherein (D) + (E ) Is 60 to 90% by weight in the total epoxy resin composition, and (D) /
An epoxy resin composition for semiconductor encapsulation, wherein the weight ratio of (E) is from 60/40 to 90/10. 2. A semiconductor device comprising a semiconductor element encapsulated with the epoxy resin composition according to claim 1.