JPH06184272A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To provide a resin composition containing a specified epoxy resin, a specific phenol resin curing agent, a specified inorganic filler and a specific curing promoter as the essential components, excellent in solder stress resistance, solder cracking resistance, heat resistance and moisture resistance and suitable for semiconductor sealing, etc. CONSTITUTION:This resin composition consists of (A) an epoxy resin containing an epoxy compound of the formula (R1 to R4 are each H, a halogen or an alkyl) in an amount of 10 to 100wt.% based on the total amount of the epoxy resin, (B) a phenol resin curing agent such as a phenolic novolak resin, (C) preferably 70 to 90wt.% inorganic filler such as fused silica powder and (D) a curing promoter such as diazabicycloundecene as the essential components.

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 is excellent in resistance to solder stress in surface mounting semiconductor devices.

[0002]

2. Description of the Related Art Conventionally, electronic parts such as diodes, transistors and integrated circuits have been sealed with a thermosetting resin. Especially in integrated circuits, orthocresol novolac epoxy resin, which has excellent heat resistance and moisture resistance, is used as phenol novolac. An epoxy resin composition cured with a resin is used. However, in recent years, as the integration of integrated circuits has increased, the size of the chips has gradually increased, and the package is a small and thin QFP, SOP, SO that is surface-mounted from the conventional DIP type.
It has changed to J, TSOP, TQFP, PLCC. That is, a large chip is enclosed in a small and thin package, cracks are generated by thermal stress, and problems such as deterioration of moisture resistance due to these cracks are greatly highlighted. In particular, when exposed to a high temperature of 200 ° C. or more in the soldering process, moisture resistance is deteriorated due to cracking of the package and peeling of the resin and the chip. Therefore, development of a highly reliable resin composition for semiconductor encapsulation suitable for encapsulating these large chips is desired.

In order to solve these problems, the use of an epoxy compound represented by the following formula (2) as an epoxy resin (Japanese Patent Laid-Open No. 64-65116) has been proposed.

[0004]

[Chemical 2] (In the formula, R _{1 to} R ₈ are the same or different atoms or groups selected from hydrogen, halogen and alkyl groups)

It has been studied. By using the epoxy compound represented by the formula (2), the viscosity of the resin system is reduced,
Therefore, by adding a larger amount of an inorganic filler such as fused silica, low thermal expansion and low water absorption can be achieved after the composition is molded, and solder stress resistance can be improved. However, even if this epoxy compound is used, there is a limit to blending a large amount of inorganic filler, and it is necessary to use a resin system capable of blending a large amount of inorganic filler in order to improve solder stress resistance. There is.

[0006]

SUMMARY OF THE INVENTION The present invention addresses these problems by using an epoxy compound represented by the formula (1) as an epoxy resin to achieve a low viscosity of a resin system and to obtain a lead. The adhesiveness is improved by increasing the wettability with the frame and the semiconductor chip, and by adding more inorganic fillers, it is possible to achieve low thermal expansion and low water absorption of the cured product. It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation in which the solder stress resistance of the semiconductor package is remarkably improved.

[0007]

The epoxy resin composition of the present invention has the following formula (1) as a compound having an epoxy group.
Hydroquinone diglycidyl ether of the molecular structure shown by

[0008]

[Chemical 3] (Wherein R _{1 to} R ₄ are the same or different atoms or groups selected from hydrogen, halogen and alkyl groups)

It is characterized by using an epoxy resin in an amount of 10 to 100% by weight with respect to the total epoxy resin, and has excellent fluidity and solder crack resistance as compared with past epoxy resin compositions.

The hydroquinone diglycidyl ether represented by the molecular structure of the formula (1) is a bifunctional monomer having two epoxy groups in one molecule obtained by glycidyl etherification of hydroquinones, and is a conventional polyfunctional monomer. It has a lower melt viscosity than functional epoxy resin and has excellent fluidity during transfer molding. Therefore, a large amount of the inorganic filler in the composition can be blended, low thermal expansion and low water absorption can be achieved, and an epoxy resin composition excellent in solder crack resistance can be obtained. By adjusting the amount of the hydroquinone diglycidyl ether used, solder crack resistance can be maximized. In order to bring out the effect of solder crack resistance, it is desirable to use the hydroquinone diglycidyl ether represented by the formula (1) in an amount of 10% by weight or more, preferably 30% by weight or more based on the total amount of epoxy resin compounds. If it is less than 10% by weight, fluidity, adhesion to lead frames and semiconductor chips, low thermal expansion,
Low water absorption cannot be obtained and solder crack resistance is insufficient.
Further, R _{1 to} R ₄ in the formula are preferably hydrogen atoms.

When another epoxy compound is used in combination with the hydroquinone diglycidyl ether represented by the formula (1), the epoxy resin to be used includes all monomers, oligomers and polymers having an epoxy group. For example, a biphenyl type epoxy compound, a bisphenol type epoxy compound, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, a triphenol methane type epoxy compound, an alkyl modified triphenol methane type epoxy compound, a triazine nucleus-containing epoxy resin, etc. .

As the curing agent used in the present invention, phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenol resin, paraxylene modified phenol resin, naphthol modified phenol resin, condensate of phenol with benzaldehyde or naphthyl aldehyde, Examples thereof include triphenol methane compounds, and phenol novolac resin, dicyclopentadiene modified phenol resin, paraxylene modified phenol resin and mixtures thereof are particularly preferable. Moreover, it is preferable to mix these curing agents so that the number of epoxy groups of the epoxy compound and the number of hydroxyl groups of the curing agent are matched.

Examples of the inorganic filler used in the present invention include fused silica powder, spherical silica powder, crystalline silica powder, secondary agglomerated silica powder, porous silica powder, alumina, etc., and particularly fused silica powder, spherical silica powder. , And a mixture of fused silica powder and spherical silica powder are preferred. Further, the blending amount of the inorganic filler is preferably 70 to 90% by weight based on the total amount of the epoxy resin composition in view of balance between solder crack resistance, moldability and fluidity.

The curing accelerator used in the present invention may be any one that accelerates the curing reaction between the epoxy group and the hydroxyl group.
What is generally used as a sealing material can be widely used. For example, diazabicycloundecene (DB
U), triphenylphosphine (TPP), dimethylbenzylamine (BDMA), 2-methylimidazole (2MZ) and the like can be mentioned, and these can be used alone or in admixture of two or more.

The epoxy resin composition of the present invention contains an epoxy resin, a curing agent, an inorganic filler and a curing accelerator as essential components, but in addition to this, a silane coupling agent, if necessary,
A variety of flame retardants such as brominated epoxy resin, antimony trioxide, hexabromobenzene, colorants such as carbon black and red iron oxide, mold release agents such as natural wax and synthetic wax, and low stress additives such as silicone oil and rubber. There is no problem even if the above-mentioned additive is properly mixed.

Further, in order to produce the encapsulating epoxy resin composition of the present invention as a molding material, the epoxy resin, the curing agent, the curing accelerator, the filler, and other additives are sufficiently uniformly mixed with a mixer or the like. After that, the mixture can be further melt-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, etc. of transistors, integrated circuits, etc., which are electric or electronic parts.

The present invention will be specifically described below with reference to examples.

【Example】

 Example 1 The following composition 9.0 parts by weight of an epoxy compound represented by the formula (3) (melting point: 110 ° C., epoxy equivalent: 130 g / eq)

[0018]

[Chemical 4]

3.0 parts by weight of the epoxy compound represented by the formula (4) (melting point 110 ° C., epoxy equivalent 190 g / eq)

[0020]

[Chemical 5]

Phenol novolac resin curing agent (softening point 90 ° C., hydroxyl group equivalent 105 g / eq) 8.8 parts by weight fused silica powder 78 parts by weight triphenylphosphine 0.2 parts by weight carbon black 0.5 parts by weight carnauba wax 0. 5 parts by weight were mixed with a mixer at room temperature, kneaded with a twin-screw roll at 70 to 100 ° C., cooled and pulverized to obtain a molding material. The molding material obtained by pulverizing was measured for spiral flow (according to EMMI-1-66) under the conditions of 175 ° C., 70 kg / cm ² , and 120 seconds using a test mold for spiral flow. Further, the obtained molding material is made into a tablet, which is then transferred to a low pressure transfer molding machine at 175 ° C. and 70 kg / cm.
² 6 × 6 for solder crack test under 120 seconds condition
mm chips were encapsulated in 52 pQFP, and 3 × 6 mm chips were encapsulated in 16 pSOP for solder moisture resistance testing. The following solder crack test and solder moisture resistance test were performed on the sealed test element.

Solder crack test: The sealed test element was treated in an environment of 85 ° C. and 85% RH for 48 hours and 72 hours, and then immersed in a solder bath at 260 ° C. for 10 seconds, and then external cracks were observed with a microscope. did. Solder moisture resistance test: sealed test element at 85 ° C, 85
% RH for 72 hours, then immersed in a solder bath at 260 ° C for 10 seconds, and then pressure cooker test (1
25 degreeC, 100% RH was performed, and the open defect of the circuit was measured. The test results are shown in Table 1.

Examples 2 to 6 Compounding was carried out according to the formulation shown in Table 1, and a molding material was obtained in the same manner as in Example 1. Using this molding material, a molded product sealed for testing was obtained, and a solder crack test and a solder moisture resistance test were carried out in the same manner as in Example 1 using this molded product. The test results are shown in Table 1.

Comparative Example 1 A molding material was obtained in the same manner as in Example 1 except that the ingredients were blended according to the formulation shown in Table 1. Using this molding material, a molded product sealed for testing was obtained, and a solder crack test and a solder moisture resistance test were carried out in the same manner as in Example 1 using this molded product. The test results are shown in Table 1.

[0025]

[Table 1]

[0026]

The epoxy resin composition of the present invention is extremely excellent in solder crack resistance and moisture resistance.

Claims (1)

[Claims] 1. An epoxy compound represented by the following formula (1): An epoxy resin containing 10 to 100% by weight (wherein R _{1 to} R ₄ in the formula are the same or different atoms or groups selected from hydrogen, halogen and alkyl groups) with respect to the total amount of the epoxy resin, (B). An epoxy resin composition for semiconductor encapsulation, which comprises a phenol resin curing agent, (C) an inorganic filler, and (D) a curing accelerator as essential components.