JPH10204256A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition for sealing semiconductors excellent in adhesion to various members such as a lead frame, solder crack and temperature cycling resistances. SOLUTION: This epoxy resin composition is obtained by adding 1-50 pts.wt. reactional product prepared by thermally reacting 100 pts.wt. epoxy resin with 5-100 pts.wt. maleic anhydride-modified polyolefin oligomer in the presence of a catalyst to 50 pts.wt. phenol resin curing agent in the epoxy resin composition comprising an epoxy resin, the phenol resin curing agent, an inorganic filter, a curing accelerator and the reactional product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low stress epoxy resin composition for semiconductor encapsulation having excellent adhesion to a lead frame.

[0002]

2. Description of the Related Art In recent years, plastic-sealed semiconductor devices such as ICs and LSIs have become the mainstream of surface-mount type devices such as QFP and SOJ. In addition, the size of the package, the size of the chip, and the fine pitch have been advanced, and requirements for solder crack resistance have also become strict. Conventional solder crack resistant epoxy resin composition (hereinafter, referred to as
Resin composition) has improved the solder crack resistance by increasing the strength of the inorganic filler by high filling and lowering the water absorption. However, in large packages, peeling under the pad is likely to occur, and the temperature cycle resistance There is also a decline. As described above, it is difficult for the conventional resin composition to achieve both solder crack resistance and temperature cycle resistance, especially for a large package.

[0003] In order to improve the solder crack resistance, in addition to the above-described techniques for increasing the strength and reducing the water absorption, each member,
In particular, it is important to improve the adhesion to the lead frame.
In order to improve the adhesion to the lead frame, a method of dimpling or slitting the lead frame has been proposed and implemented. Further, by using a silane coupling agent or adjusting a wax as a release agent, the adhesion can be improved to some extent. However, since the solder crack resistance has come to be determined by peeling, stricter requirements have been placed on the adhesiveness, and the current method alone has become insufficient. To improve the temperature cycle resistance, conventionally, silicone oil or the like has been added, or a reaction product of a silicone oil and an epoxy resin or a phenol resin has been added to reduce the elastic modulus. When the resin is used, there arises a problem that the resin strength is reduced and the adhesion to each member is also reduced. On the other hand, when the low stress agent is not used, there is a problem that the temperature cycle resistance is reduced.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been studied in various ways, and by using a reaction product of an epoxy resin and a maleic anhydride-modified polyolefin oligomer, a lead frame or the like has been developed. An object of the present invention is to provide a resin composition having excellent adhesion to various members, solder crack resistance, and temperature cycle resistance.

[0005]

That is, the present invention provides (A)
An epoxy resin, (B) a phenolic resin curing agent, (C) an inorganic filler, (D) a curing accelerator, and (E) 100 parts by weight of an epoxy resin and 5 to 100 parts by weight of a maleic anhydride-modified polyolefin oligomer as a catalyst In an epoxy resin composition comprising a reaction product obtained by heating and reacting in the presence, with respect to 50 parts by weight of a phenol resin curing agent (B),
An epoxy resin composition comprising 1 to 50 parts by weight of the reaction product (E).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in the molecule. For example, ortho-cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol type epoxy compound, naphthalene type epoxy compound, triphenolmethane type epoxy resin,
Examples include triazine nucleus-containing epoxy resins, biphenyl-type and stilbene-type epoxy compounds, and modified resins thereof. In order to improve the moisture resistance of the resin composition, it is desirable that impurity ions such as chlorine ions and sodium ions be as small as possible. Also, for the curability of the resin composition,
The epoxy equivalent is preferably about 150 to 300 g / eq.

The phenolic resin curing agent used in the present invention is not particularly limited as long as it has a phenolic hydroxyl group in the molecule. For example, phenol novolak resin, dicyclopentadiene-modified phenol resin,
Examples include xylylene-modified phenolic resins, triphenolmethane resins, and modified resins thereof. For the curability of the resin composition, the hydroxyl equivalent is 80 to 250 g /
eq is preferable.

As the inorganic filler used in the present invention, for example, fused silica powder, spherical silica powder, crystalline silica powder, alumina and the like can be used, and a mixture of fused silica powder and spherical silica powder is particularly desirable. . These inorganic fillers are appropriately selected and adjusted according to required characteristics.

As the curing accelerator used in the present invention, those generally used in a sealing resin composition can be widely used. Representative examples include 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, benzyldimethylamine, 2-methylimidazole and the like. These may be used alone or as a mixture. Good.

The maleic anhydride-modified polyolefin oligomer used in the reaction product (E) of the present invention is preferably a maleic anhydride-modified polyethylene oligomer or a maleic anhydride-modified polypropylene oligomer. If it is other than these, the adhesion becomes insufficient, and a defect such as peeling tends to occur in a soldering resistance test. An epoxy resin and a maleic anhydride-modified polyolefin oligomer are heated and reacted in advance in the presence of a catalyst to obtain a reaction product (E). By using this reaction product as one component of the resin composition, a lead frame is obtained. It is possible to improve the adhesion to various members such as, and to reduce the elastic modulus. The mixing ratio of the maleic anhydride-modified polyolefin oligomer and the epoxy resin is such that the maleic anhydride-modified polyolefin oligomer is 5 to 10 parts by weight per 100 parts by weight of the epoxy resin.
0 parts by weight is preferred. If the amount of the maleic anhydride-modified polyolefin oligomer is less than 5 parts by weight, the effect of improving the adhesiveness is small, and if it exceeds 100 parts by weight, the melt viscosity of the reaction product is undesirably high. The same epoxy resin as described above may be used for the reaction. The reaction conditions for obtaining the reaction product (E) of the maleic anhydride-modified polyolefin oligomer and the epoxy resin are preferably a temperature of 80 to 180 ° C. and a reaction time of about 30 minutes to 8 hours. When the temperature is lower than 80 ° C., the melt viscosity of the epoxy resin used for the reaction is high, and the epoxy resin is not sufficiently uniformly mixed with the maleic anhydride-modified polyolefin oligomer.
If the temperature exceeds ℃, the reaction proceeds excessively, and the melt viscosity of the reaction product increases, which is not preferable. As a catalyst for accelerating these reactions, for example, 1,8-diazabicyclo (5,
(4,0) undecene-7, triphenylphosphine, benzyldimethylamine, 2-methylimidazole, and the like, but are not limited thereto.

The amount of the reaction product is preferably 1 to 50 parts by weight based on 50 parts by weight of the phenol resin curing agent. If the amount is less than 1 part by weight, the effect of improving the adhesion is small, which is not preferable. If the amount is more than 50 parts by weight, the melt viscosity of the resin composition at the time of molding becomes high, and molding defects such as wire sweep and pad shift occur, which is not preferable.

In addition to the components (A) to (E), the resin composition of the present invention may further comprise, if necessary, a coupling agent such as a silane coupling agent, a flame retardant such as antimony oxide or a brominated epoxy resin; Coloring agents such as black, natural wax,
Various additives such as a release agent such as a synthetic wax may be appropriately compounded. The resin composition of the present invention comprises (A)
(E) The component and other additives are sufficiently and uniformly mixed at room temperature using a mixer or the like, and further melt-kneaded with a hot roll or a kneader, cooled, and pulverized.

Production Example 1 of Reaction Product Epoxy resin (softening point 65 ° C., epoxy equivalent 195) 1
00 parts by weight was heated to 120 ° C. and melted, and 20 parts by weight of a maleic anhydride-modified polyethylene oligomer (manufactured by Sanyo Chemical Industries, Ltd., Umex 2000) was added and mixed and dissolved. 1 part by weight of triphenylphosphine was added to this mixture, and the mixture was heated at 120 ° C. for 2 hours.
After cooling and pulverizing, a reaction product was obtained. This is called reaction product 1
And Production example 2 of reaction product Epoxy resin (softening point 65 ° C., epoxy equivalent 195) 1
00 parts by weight were heated and melted at 120 ° C., and 3 parts by weight of maleic anhydride-modified polyethylene oligomer (manufactured by Sanyo Chemical Industries, Ltd., Umex 2000) was added and mixed and dissolved. 1 part by weight of triphenylphosphine was added to this mixture, and the mixture was heated at 120 ° C. for 2 hours.
After cooling and pulverizing, a reaction product was obtained. This is called reaction product 2
And Production example 3 of reaction product Epoxy resin (softening point 65 ° C., hydroxyl equivalent 195) 10
0 parts by weight were heated to 120 ° C. and melted, and the resulting mixture was mixed with maleic anhydride-modified polyethylene oligomer (Sanyo Chemical Industries, Ltd.)
・ Manufactured by Umex 2000) 120 parts by weight
Mix and dissolve. To this mixture was added 1 part by weight of triphenylphosphine, heated at 160 ° C. for 2 hours, and then cooled.
Pulverization gave a reaction product. This is designated as reaction product 3.

[0014]

The present invention will be specifically described below with reference to examples. The raw materials used in Examples and Comparative Examples are as follows. The composition is shown in Table 1. The mixing ratio is by weight. Orthocresol novolak type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., ESCN-195L, epoxy equivalent: 1)
95) Phenol novolak resin (softening point: 95 ° C., hydroxyl equivalent: 105) Fused silica powder 2-methylimidazole Reaction product 1, 2, or 3 Maleic anhydride-modified polyethylene oligomer (manufactured by Sanyo Chemical Industries, Ltd., Umex 2000) Silicone oil (KE-1 manufactured by Shin-Etsu Chemical Co., Ltd.)
02) Silane coupling agent Antimony trioxide Brominated epoxy resin Carbon black Carnauba wax was mixed using a Henschel mixer according to the composition shown in Table 1, kneaded at 70-100 ° C using a biaxial roll, cooled, and ground to obtain a resin. The composition was used. After tableting the obtained resin composition, it was evaluated by the following method.

Evaluation method: Solder crack resistance: An 80-pin QFP was molded using a low-pressure transfer molding machine at 175 ° C., 70 kg / cm ² , for 120 seconds.
A treatment was performed at 75 ° C. for 8 hours to obtain a molded product. The molded article was subjected to a solder crack resistance test by IR reflow (220 ° C.) after absorbing moisture for 192 hours in an atmosphere of 30 ° C. and a relative humidity of 60%. Temperature cycle resistance: 80-pin QFP was molded using a low-pressure transfer molding machine at 175 ° C., 70 kg / cm ² , and 120 seconds, and was further used as a post-mold cure.
A treatment was performed at 75 ° C. for 8 hours to obtain a molded product. After the molded article was absorbed in an atmosphere of 30 ° C. and a relative humidity of 60% for 192 hours, a temperature cycle resistance test was performed at −65 ° C. to 150 ° C.
For 1,000 cycles. Adhesion with a lead frame: A resin composition was molded on a lead frame using a low-pressure transfer molding machine at 175 ° C., 70 kg / cm ² and 120 seconds, and further subjected to post-mold cure at 175 ° C. for 8 hours. The test was performed to obtain a test piece. The adhesion of the test piece to the lead frame was measured using a Tensilon universal testing machine at 240 ° C. and a shear rate of 2 mm / min, and the shear strength (unit: kgf /
mm ² ).

Evaluation Results Examples 1 and 2 By adding the reaction product 1, good results were obtained in both solder crack resistance and temperature cycle resistance.

COMPARATIVE EXAMPLE 1 When the reaction product 2 containing a small amount of the maleic anhydride-modified polyethylene oligomer was used, the solder crack resistance,
Both temperature cycle resistance was insufficient, and the effect of the addition could not be sufficiently exhibited. Comparative Example 2 When the reaction product 3 containing a large amount of the maleic anhydride-modified polyethylene oligomer was used, the viscosity was high, the moldability was poor, and no molded product was obtained. Comparative Example 3 When the addition amount of the reaction product 1 was small, the adhesion and the low elastic modulus were insufficient, and good results were not obtained in both the solder crack resistance and the temperature cycle resistance, which was not preferable. Comparative Example 4 When the amount of reaction product 1 was large, the melt viscosity of the resin composition was high, moldability was poor, and a molded product was not obtained. Comparative Example 5 When the maleic anhydride-modified polyethylene oligomer was added without previously reacting, voids were generated during molding, which was not preferable. Comparative Example 6 When silicone oil was added in place of the maleic anhydride-modified polyethylene oligomer, the adhesion was insufficient, and a failure occurred in a solder crack resistance test, which was not preferable. The above results are summarized in Table 1.

[0018]

[Table 1]

[0019]

According to the present invention, a surface mount type IC is provided.
An epoxy resin composition that achieves both the adhesion to the lead frame required for the package, the resistance to solder cracking, and the resistance to temperature cycling can be obtained, and can be widely applied to the high reliability requirements of ICs and LSIs.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23/26 C08L 23/26 61/06 61/06 H01L 23/29 H01L 23/30 R 23/31

Claims (1)

[Claims] 1. An epoxy resin, (B) a phenol resin curing agent, (C) an inorganic filler, (D) a curing accelerator, and (E) 100 parts by weight of an epoxy resin, and maleic anhydride-modified polyolefin oligomer 5 Phenol resin curing agent (B) in an epoxy resin composition consisting of a reaction product obtained by heat-reacting with 100 parts by weight in the presence of a catalyst.
An epoxy resin composition obtained by adding 1 to 50 parts by weight of the reaction product (E) to 50 parts by weight.