JP3317473B2 - 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, which has excellent solder heat resistance and good storage characteristics at room temperature.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are sealed with a thermosetting resin composition. Particularly, in an integrated circuit, an O-cresol novolac epoxy having excellent heat resistance and moisture resistance is used. An epoxy resin composition obtained by curing a resin with a novolak type phenol resin is used. However, in recent years, the chip has been gradually increased in size with the increase in the degree of integration of integrated circuits, and conventional DIP
Small, thin flat package, SOP, TSOP, SOJ, QFP, TQFP, surface mounted from type
And so on. That is, a large chip is sealed in a small and thin package, and cracks are generated due to stress, and problems such as a decrease in moisture resistance due to the cracks have been greatly highlighted. In particular, there has been a problem in that abrupt exposure to a high temperature of 200 ° C. or more in a soldering process causes a crack in a package and a peeling of a resin and a chip to deteriorate moisture resistance. Development of a highly reliable sealing resin composition suitable for sealing these large chips has been desired.

[0003] In order to solve these problems, as a result of various studies, a large amount of an inorganic filler such as fused silica is blended, and a low-viscosity resin is used as a resin system.
The heat stress resistance during soldering, that is, the solder heat resistance, has been considerably improved. As an inorganic filler, by adjusting the particle size distribution and shape of the fused silica, without decreasing the fluidity, it is possible to blend a large amount of fused silica,
Low water absorption, low thermal expansion, and high strength of the resin composition are achieved. In addition, by using a relatively low-molecular epoxy resin such as a biphenyl type or a naphthalene type as a resin system, high adhesion, toughness, low water absorption can be achieved, and low viscosity, so that fused silica is used. Large amounts can be blended. But,
The method of blending a large amount of fused silica and using a low-viscosity resin has the following problems. This is because the resin has a low viscosity and has a low molecular weight, so that the molecules are easy to move, and the reaction easily proceeds even at room temperature, so that the room temperature storage characteristics are deteriorated. That is, when the resin composition is stored at room temperature, the fluidity is reduced, so at the time of molding, gold wire deformation,
Problems such as island shift and poor filling occur.
Therefore, it has good room temperature storage characteristics and excellent solder heat resistance.
Development of a sealing resin composition has been desired.

[0004]

SUMMARY OF THE INVENTION The present invention solves such a problem by using an epoxy resin of the formula (1) to provide a semiconductor encapsulation having excellent solder heat resistance and good room temperature storage characteristics. The present invention provides an epoxy resin composition for use.

[0005]

The present invention relates to (A) an epoxy resin containing an epoxy resin represented by the following formula (1) in an amount of 30 to 100% by weight based on the total epoxy resin amount, and (B) a phenol resin curing agent. , (C) a curing accelerator, and (D) a fused silica as an essential component, and 75 to 93% by weight of the fused silica in the entire composition. is there.

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The epoxy resin represented by the formula (1) has particularly good room-temperature storage characteristics as compared with the epoxy resins represented by the formulas (2) and (3). In addition, it has excellent properties such as low water absorption, adhesion, hot strength and solder heat resistance. Equation (1)
By adjusting the amount of the epoxy resin used in the formula (1), the room temperature storage characteristics and the solder heat resistance can be maximized. In order to achieve the effect, it is desirable to use the epoxy resin represented by the formula (1) in an amount of 30% by weight or more, preferably 50% by weight or more of the total epoxy resin amount. If it is less than 30% by weight, the room temperature storage characteristics or the solder heat resistance is reduced.

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Embedded image When an epoxy resin other than the epoxy resin of the formula (1) is used in combination, the epoxy resin to be used is generally a polymer having an epoxy group, for example, a bisphenol epoxy resin, a cresol novolak epoxy resin, a biphenyl epoxy resin, There are a trifunctional epoxy resin such as a phenol novolak type epoxy resin, a triphenolmethane type epoxy resin, an alkyl-modified triphenolmethane type epoxy resin, and a triazine nucleus containing epoxy resin, and these may be used alone or in combination.

The phenolic resin curing agent used in the present invention comprises:
All polymers having a phenolic hydroxyl group include, for example, phenol novolak resins, cresol novolak resins, phenol aralkyl resins, dicyclopentadiene-modified phenol resins, terpene-modified phenol resins, and the like. These resins may be used alone or as a mixture.

The curing accelerator used in the present invention may be any one which promotes the reaction between an epoxy group and a phenolic hydroxyl group, and those generally used for a sealing material can be widely used. , 1,8-diazabicycloundecene, triphenylphosphine, benzyldimethylamine, 2-methylimidazole, and the like, and these may be used alone or as a mixture.

The fused silica used in the present invention includes crushed fused silica, spherical fused silica, and the like, and the compounding amount is 75 to 93% by weight based on the total composition. If it is less than 75% by weight, water absorption and thermal expansion increase, and solder heat resistance is insufficient.
If it exceeds 93% by weight, the fluidity is reduced and the moldability is deteriorated.

The epoxy resin composition for encapsulation of the present invention comprises an epoxy resin, a phenol resin curing agent, a curing accelerator, and fused silica as essential components. In addition to this, a silane coupling agent, a bromo coupling agent, Flame retardants such as fluorinated epoxy resin, antimony trioxide, hexabromobenzene, coloring agents such as carbon black and red iron oxide, release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber. There is no problem if additives are appropriately compounded. In addition, in order to manufacture the sealing epoxy resin composition of the present invention as a molding material, epoxy resin, phenol resin curing agent, curing accelerator, fused silica, and other additives were sufficiently uniformly mixed by a mixer or the like. Thereafter, the mixture is further melt-kneaded with a hot roll or a kneader, cooled, and pulverized to obtain a molding material. These molding materials can be applied to sealing of electronic parts or electric parts, coating insulation, and the like.

[0011]

The present invention will be specifically described below with reference to examples. Example 1-Epoxy resin represented by the following formula (1): 8.80 parts by weight-Phenol novolak resin curing agent: 6.15 parts by weight (softening point 85 ° C, hydroxyl equivalent 105)-1,8-diazabicyclo (5 (4,0) undecene-7 (DBU): 0.25 parts by weight Spherical fused silica (average particle size 15 μm): 84.00 parts by weight Carnauba wax: 0.50 parts by weight Carbon black: 0.30 parts by weight The parts were mixed at room temperature with a mixer, kneaded at 80 to 100 ° C. with a biaxial roll, cooled and pulverized to obtain a molding material. The obtained molding material was subjected to a spiral flow, a normal temperature storage property, a solder cracking property and a solder moisture resistance test. Table 1 shows the evaluation results.

<< Evaluation Method >> Spiral flow: A mold for measuring spiral flow according to EMMI-I-66 was used.
The measurement was performed at an injection pressure of 70 kg / cm ² and a curing time of 2 minutes. -Room temperature storage: After storing the resin composition at 25 ° C for one week, the spiral flow was measured. The percentage when the initial spiral flow length is taken as 100% is shown in%. -Solder cracking property: 52pQ with a chip size of 6 x 6mm
FP was heated at a mold temperature of 175 ° C, an injection pressure of 70 kg / cm ² ,
The molded product was molded at a curing time of 2 minutes,
Post cured in time. This molded product was treated in an environment of 85 ° C. and 85% RH for 48 hours, 72 hours, and 120 hours, then immersed in a solder bath at 260 ° C. for 10 seconds, and then subjected to a total number of 1 under a microscope.
Six external cracks were observed and represented by the number of cracks out of 16. -Solder moisture resistance: 52pQFP with a chip size of 6 x 6mm
Was molded at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² and a curing time of 2 minutes, and the obtained molded article was post-cured at 175 ° C. for 8 hours. This molded product was treated in an environment of 85 ° C. and 85% RH for 72 hours, then immersed in a solder bath at 260 ° C. for 10 seconds, and then subjected to a pressure cooker test (125 ° C., 100% RH).
% RH), and the open failure of the circuit was measured.

<< Examples 2 to 5, Comparative Examples 1 to 6 >> According to the compositions shown in Tables 1 and 2, a molding material was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2. The epoxy resins used in the examples and comparative examples show the structural formulas of the formulas (1), (2) and (3), and the ortho-cresol novolac type epoxy resin has a softening point of 65 ° C. An epoxy equivalent of 200 was used.

Table 1 Example 1 2 3 4 5 Blended (parts by weight) Epoxy resin of formula (1) 8.80 5.41 3.66 5.19 5.50 Epoxy resin of formula (2) 3.61 5.48 Epoxy resin of formula (3) 3.46 orthocreso-rnophorac-type epoxy resin 3.67 pheno -Renophorac resin curing agent 6.15 5.93 5.81 6.30 5.78 DBU 0.25 0.25 0.25 0.25 0.25 Spherical fused silica 84.00 84.00 84.00 84.00 84.00 Carnauba wax 0.50 0.50 0.50 0.50 0.50 Carbon black 0.30 0.30 0.30 0.30 0.30 Spiral flow (cm) 96 98 93 84 85 Room temperature Storage property (%) 92 89 86 85 93 Solder cracking property Moisture absorption 48 hours 0000 (cracks / 16) Moisture absorption 72 hours 0 0 0 0 0 Moisture absorption 120 hours 0 0 0 0 4 Average life of solder moisture resistance ( Time)>500>500>500>500> 500

Table 2 Comparative Example 1 2 3 4 5 6 Formulation (parts by weight) Epoxy resin of formula (1) 1.85 14.68 2.91 Epoxy resin of formula (2) 9.38 7.41 Epoxy resin of formula (3) 8.44 Orthocreso-Lenophorac-type epoxy resin 9.80 Pheno- Renophorac resin curing agent 5.57 6.51 5.15 5.69 10.27 2.04 DBU 0.25 0.25 0.25 0.25 0.25 0.25 Spherical fused silica 84.0 84.0 84.0 84.0 74.0 94.0 Carnauba wax 0.50 0.50 0.50 0.50 0.50 0.50 Carbon black 0.30 0.30 0.30 0.30 0.30 0.30 Spiral flow (cm) 94 72 69 97 143 28 Room temperature storability (%) 77 69 94 78 92 89 Solder crackability Moisture absorption 48 hours 0 0 0 0 1 0 (number of cracks / 16) Moisture absorption 72 hours 0 0 7 0 5 0 Moisture absorption 120 hours 0 0 16 0 160 Solder moisture resistance average life (hours)>500> 500 250> 500 350> 500

[0017]

According to the present invention, a resin composition having excellent solder heat resistance can be obtained, and the conventional drawback of good storage properties at room temperature is very useful as a resin composition for sealing semiconductors for surface mounting. And the industrial value is enormous.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 23/31 (58) Investigated field (Int.Cl. ⁷ , DB name) C08G 59/26 C08G 59/62 C08K 3/36 C08L 63 / 02 H01L 23/29

Claims (1)

(57) [Claims] 1. An epoxy resin containing (A) an epoxy resin represented by the following formula (1) in an amount of 30 to 100% by weight based on the total amount of epoxy resin, (B) a phenol resin curing agent, and (C)
An epoxy resin composition for semiconductor encapsulation, comprising a curing accelerator and (D) fused silica as essential components, and comprising 75 to 93% by weight of the fused silica in the entire composition. Embedded image