JPH0952939A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition containing respective specific epoxy resin and dicyclopentadiene-modified dihydroxybenzene resin curing agent as essential components and capable of remarkably improving soldering stress resistance in the mounting of a semiconductor package. SOLUTION: This composition contains (A) an epoxy resin containing 30-100wt.% (based on the total epoxy resin) of an epoxy resin of formula I ((n) is 0-20; R is H, an alkyl or a halogen), (B) a curing agent containing 30-100wt.% (based on the total curing agent) of a dicyclopentadiene-modified dihydroxybenzene resin curing agent of formula II ((n) is 0-20), (C) an inorganic filler (preferably spherical silica powder, etc.) and (D) a cure accelerator (e.g. triphenylphosphine) as essential components. The epoxy resin of formula I is preferably produced by the glycidyl etherification of a biphenyl-type bifunctional phenol compound with epichlorohydrin. The curing agent of formula II is preferably produced by polymerizing a dihydroxybenzene with dicyclopentadiene by Diels-Alder reaction.

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 solder stress resistance in surface mounting of semiconductor devices.

[0002]

2. Description of the Related Art Conventionally, electronic components such as diodes, transistors, and integrated circuits are sealed with a thermosetting resin.
Particularly in integrated circuits, an epoxy resin composition in which an ortho-cresol novolac type epoxy resin having excellent heat resistance and humidity resistance is cured with a phenol novolac resin and an inorganic filler such as fused silica or crystalline silica is used as a filler is used. ing. However, in recent years, as the integration of integrated circuits has increased, the size of the chip has gradually increased, and the package is a small and thin QF that is surface-mounted from the conventional DIP type.
It has been changed to P, SOP, SOJ, TSOP, TQFP, PLCC. That is, since a large chip is enclosed in a small and thin package, thermal stress causes cracks, and problems such as deterioration of moisture resistance due to these cracks are greatly highlighted. In particular, in the soldering process, when exposed to a high temperature of 200 ° C. or more, the moisture resistance is deteriorated due to cracking of the package or 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.

[0003]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention uses an epoxy resin represented by the formula (1) as an epoxy resin and a dicyclopentadiene represented by the formula (2) as a curing agent. The use of the modified dihydroxybenzene resin curing agent is thought to improve the orientation when forming a crosslinked structure. Therefore, the epoxy resin composition for semiconductor encapsulation has significantly improved the solder stress resistance of the semiconductor package during mounting. Is in the place of providing.

[0004]

The epoxy resin composition of the present invention comprises (A) an epoxy resin containing the epoxy resin represented by the following formula (1) in an amount of 30 to 100% by weight based on the total amount of the epoxy resin:

[0005]

Embedded image (N = 0 to 20) (R in the formula is the same or different atom or group selected from hydrogen, alkyl group and halogens)

(B) A curing agent containing a dicyclopentadiene-modified dihydroxybenzene resin curing agent represented by the following formula (2) in an amount of 30 to 100% by weight based on the total amount of the curing agent,

[0007]

Embedded image (N = 0 to 20)

An epoxy resin composition for semiconductor encapsulation, which comprises (C) an inorganic filler and (D) a curing accelerator as essential components.
It has excellent solder stress resistance. Equation (1)
The epoxy resin represented by the molecular structure of is obtained by glycidyl etherification of a biphenyl type bifunctional phenol compound with epichlorohydrin. Compared with the conventional cresol novolac epoxy resin, it has a low viscosity at the time of melting and is suitable for high filling of the inorganic filler in the composition. Therefore, the value of n in the formula is preferably as close as possible to the value of 0, that is, the more compounds of n = 0 are desirable,
Particularly, it is preferable that the ratio of n = 0 is 80% or more in order to increase the filling of the inorganic filler. By adjusting the amount of the epoxy resin used, solder stress resistance can be maximized. In order to bring out the effect of resistance to soldering stress, 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, based on the total amount of epoxy resin. If it is less than 30% by weight, the intended solder stress resistance is insufficient. When another epoxy resin is used in combination with the epoxy resin represented by the formula (1), a compound having two or more epoxy groups or a polymer in general may be used. For example,
Examples include phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenol methane type epoxy resin, and alkyl modified triphenol methane type epoxy resin.

The dicyclopentadiene-modified dihydroxybenzene resin curing agent represented by the molecular structure of the formula (2) is obtained by polymerizing dihydroxybenzene and dicyclopentadiene by the Diels-Alder reaction. Compared with the conventional phenol novolac resin, it has low hygroscopicity and is excellent in adhesion to metals such as lead frame (42 alloy, copper alloy) and silicon chips. Further, due to the influence of dihydroxybenzene, the strength of the rubber region when heated is improved. By adjusting the amount of the dicyclopentadiene-modified dihydroxybenzene resin curing agent used, solder stress resistance can be maximized. In order to bring out the effect of resistance to solder stress, it is desirable to use the resin curing agent of the formula (2) in an amount of 30% by weight or more, preferably 50% by weight or more, based on the total amount of the resin curing agent. If it is less than 30% by weight, the intended solder stress resistance is insufficient. When another resin curing agent is used in combination with the resin curing agent of the formula (2), all polymers having a hydroxyl group may be used. For example, phenol novolac resin, cresol novolac resin, dicyclopentadiene modified phenol resin, para-xylylene modified phenol resin, terpene modified phenol resin, triphenol methane compound and the like, particularly phenol novolac resin, dicyclopentadiene modified phenol resin, para-xylene Modified phenolic resins, terpene modified phenolic resins and mixtures thereof are preferred. The amount of these curing agents to be added is preferably such that the number of epoxy groups in the epoxy compound matches the number of hydroxyl groups in the curing agent.

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, and the like, particularly spherical silica powder and fused silica. A mixture of powder and spherical silica powder is preferred. Further, the amount of the inorganic filler compounded is preferably 80 to 90% by weight based on the total amount of the epoxy resin composition in terms of resistance to solder stress. When the amount of the inorganic filler is less than 80% by weight, low thermal expansion and low water absorption cannot be obtained, and the solder stress resistance is insufficient. Further, if the amount of the inorganic filler is 90% by weight or more, problems such as die pad in the semiconductor package and displacement of the gold wire will occur due to high viscosity. The curing accelerator used in the present invention may be any one as long as it accelerates the curing reaction between the epoxy group and the hydroxyl group, and those generally used for encapsulating materials can be widely used. Examples include diazabicycloundecene, triphenylphosphine, dimethylbenzylamine, 2-methylimidazole, and the like, which may be used alone or in combination.

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. In addition to these components, a silane coupling agent, a brominated epoxy resin, and an oxidation agent may be added as required. Combining various additives such as flame retardants such as antimony and hexabromobenzene, coloring agents 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. It doesn't matter. In order to produce the encapsulating epoxy resin composition of the present invention as a molding material, after the epoxy resin, a curing agent, an inorganic filler, a curing accelerator, and other additives are sufficiently uniformly mixed with a mixer or the like, Further, it can be melt-kneaded with a hot roll or a kneader, cooled and then 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 1 6.84 parts by weight of an epoxy resin represented by the formula (3) (melting point: 150 ° C., epoxy equivalent: 154 g / eq)

[0013]

Embedded image (It is a mixture in which the value of n is 0 to 2, and the weight ratio is 1 for n = 0 and 0.09 for n = 1 and 0.0 for n = 2.
2. )

Orthocresol novolac type epoxy resin (softening point 58 ° C., epoxy equivalent 200 g / eq) 1.17 parts by weight Dicyclopentadiene-modified catechol resin curing agent represented by the formula (4) (softening point 106 ° C., hydroxyl equivalent) 98 g / eq) 4.20 parts by weight

[0015]

[Chemical 6] (It is a mixture in which the value of n is 0 to 3, and the weight ratio thereof is 1 for n = 0 and 0.65 for n = 1 and 0.4 for n = 2.
1, and n = 3 is 0.28. )

Phenol novolac resin curing agent (softening point 65 ° C., hydroxyl group equivalent 105 g / eq) 1.05 parts by weight fused silica powder (average particle size 10 μm, specific surface area 2.0 m ² / g) 35 parts by weight spherical silica powder ( Average particle diameter 30 μm, specific surface area 2.5 m ² / g) 50 parts by weight 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) 0.2 parts by weight carbon black 0.5 parts by weight Carnauba wax 0 0.5 parts by weight are mixed with a mixer at room temperature, and the mixture is mixed at 70 to 100 ° C. for 2 hours.
The mixture was kneaded by a shaft roll, cooled and pulverized to obtain a molding material. The obtained molding material is made into tablets, which are then subjected to a low pressure transfer molding machine at 175 ° C., 70 kg / cm ² , 120
Under the condition of seconds, a 6 × 6 mm chip was sealed in 52pQFP for a solder stress test, and a 3 × 6mm chip was sealed in 16pSOP for a solder moisture resistance test.

The following solder stress test and solder moisture resistance test were conducted on the sealed test element. Solder stress test: Sealed test element at 85 ° C
Treated in an environment of 85% RH for 24 hours, 48 hours, 72 hours and 120 hours, and then immersed in a solder bath at 260 ° C for 10 seconds, and then observed external cracks with a microscope (number of cracks generated / total number). Expressed as Solder moisture resistance test: Sealed test element at 85 ° C, 8
After being treated for 72 hours in an environment of 5% RH and then immersed in a solder bath at 260 ° C. for 10 seconds, a pressure cooker test was performed to measure the open circuit failure. Bending strength test: 240 according to JIS K 6911
Measured in ° C. Table 1 shows the evaluation results.

Examples 2 to 6 Compounding was performed according to the formulation shown in Table 1, and a molding material was obtained in the same manner as in Example 1. A molded product sealed with these molding materials for the test was obtained, and a solder stress test and a solder moisture resistance test were conducted using this molded product in the same manner as in Example 1. Table 1 shows the evaluation results.
Shown in Comparative Examples 1 to 6 Compounding was carried out according to the prescription of Table 2, and a molding material was obtained in the same manner as in Example 1. Sealed molded products for testing were obtained from these molding materials, and solder stress tests and solder moisture resistance tests were conducted using the molded products in the same manner as in Example 1. Table 2 shows the evaluation results
Shown in The dicyclopentadiene-modified phenol resin curing agent of the formula (5) used in Comparative Examples 5 and 6 had a softening point of 1
06 ° C., hydroxyl equivalent 195 g / eq, n is a mixture showing a value of 0 to 3, and the weight ratio of n = 0 is 1, n = 1 is 0.75, n = 2 is 0.45, n = 3 is 0.2
0.

[0015]

[Chemical 7]

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

The semiconductor package sealed with the resin composition of the present invention remarkably improves the solder stress resistance during mounting.

Claims (1)

[Claims] 1. An epoxy resin represented by the following formula (1): (A) 30 to 100% by weight based on the total amount of epoxy resin.
Epoxy resin containing, (N = 0 to 20) (R in the formula is the same or different atom or group selected from hydrogen, alkyl group, and halogens) (B) Dicyclopentadiene modification represented by the following formula (2) A curing agent containing a dihydroxybenzene resin curing agent in an amount of 30 to 100% by weight based on the total amount of the curing agent, (N = 0 to 20) An epoxy resin composition for semiconductor encapsulation, which comprises (C) an inorganic filler and (D) a curing accelerator as essential components.