JPH03128920A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To prepare a semiconductor-sealing epoxy resin compsn. excellent in the resistance to soldering stress by compounding a specific epoxy resin with a specific curing agent. CONSTITUTION:An epoxy resin compsn. is prepd. by compounding the following as the essential components: an epoxy resin contg. 50-100wt.% (based on the total epoxy resin) trifunctional epoxy resin of formula I (wherein R1 to R11 are each H, halogen, or alkyl) (e.g. an epoxy resin of formula II); a curing agent contg. 40-100wt.% (based on the total curing agent) dicyclopentadiene- modified phenol resin of formula III (wherein R1 and R2 are each H, halogen, or alkyl) [e.g. a resin of formula IV (wherein (n) is 1 or 2; and the phenol resin comprises a mixture of 20% resin with n=1 and 80% resin with n=2)]; an inorg; filler; and a curing accelerator. The compsn. is excellent in the resistance to soldering stress and suitably used for semiconductor sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an epoxy resin composite for semiconductor encapsulation that has excellent solder stress resistance.

(Prior art) Conventionally, electronic components such as diodes, transistors, and integrated circuits have been encapsulated with thermosetting resins. Especially for integrated circuits, 0-cresol novolac epoxy resin, which has excellent heat resistance and moisture resistance, has been encapsulated with novolac resin. Epoxy resin cured with phenolic resin is used.

However, in recent years, as integrated circuits have become more highly integrated, chips have become larger and larger, and packages have changed from the conventional DIP type to surface-mounted small, thin flat packages.
For example, it is changing to SOP, SOJ, and PLCC.

That is, a large chip is enclosed in a small and thin package, and problems such as the occurrence of cracks due to stress and a decrease in moisture resistance due to these cracks have been brought into focus.

Particularly in the soldering process, rapid exposure to high temperatures of 200° C. or higher has caused problems such as cracking of the package and deterioration of moisture resistance due to peeling of the resin and chip.

It has been desired to develop a highly reliable sealing resin composition suitable for sealing these large chips.

In order to solve these problems, thermoplastic oligomers were added (Japanese Patent Laid-Open No. 62-2010) to alleviate the thermal shock during soldering.
-115849) and addition of various silicone compounds (JP-A-62-115850, 62-1166).
54 Publication No. 62-128162) and silicone modification (Japanese Unexamined Patent Publication No. 62-128160), but in both cases cracks occur in the package during soldering, making it difficult to package semiconductors with excellent reliability. However, it has not been possible to obtain an epoxy resin composition for stopping use.

On the other hand, in order to obtain a heat-resistant epoxy resin composition with excellent solder stress resistance, the use of a polyfunctional epoxy resin as the resin system (Japanese Unexamined Patent Publication No. 168620/1983) has been considered; The use of epoxy resin increases the crosslinking density and improves heat resistance, especially from 200°C to 300'
When exposed to high temperatures such as O, the solder stress resistance was insufficient.

(Problems to be Solved by the Invention) The present invention solves these problems by using a trifunctional epoxy resin as the epoxy resin and a dicyclopentadiene-modified phenol resin as the curing agent, thereby improving solder stress resistance. It is an object of the present invention to provide an extremely excellent epoxy resin composition for semiconductor encapsulation.

(Means for Solving the Problems) The epoxy resin composition of the present invention includes, as an epoxy resin,
A trifunctional epoxy resin having a structure represented by the following formula (I) (in the formula, R1 to R11 are atoms or groups selected from hydrogen, halogen, and alkyl groups) is added in an amount of 50 to 100% by weight based on the total amount of epoxy resin. % of an epoxy resin, and a dicyclopentadiene-modified phenol having a structure represented by the following formula (II) as a curing agent (wherein R,, R2 are atoms or groups selected from hydrogen, halogen, and alkyl groups) It is characterized by using a curing agent containing 40 to 100% by weight based on the total amount of curing agent, and has extremely excellent solder stress resistance compared to conventional epoxy resin compositions.

By adjusting the amount of the trifunctional epoxy resin having the structure represented by formula (I), the solder stress resistance can be maximized.

In order to obtain the effect of solder stress resistance, it is desirable to use the trifunctional epoxy resin represented by formula (I) in an amount of 50% by weight or more, preferably 70% by weight or more of the total amount of epoxy resin.

If it is less than 50% by weight, the crosslinking density will not increase and the solder stress resistance will be insufficient.

Furthermore, R1, R2, R4-R7, R+ o, R in the formula
+ is preferably a hydrogen atom, and R3, R,, R, is preferably a methyl group.

In addition, if the epoxy resin is difunctional or less, the crosslinking density will not increase, the heat resistance will be poor, and the effect of solder stress resistance will not be obtained.

The epoxy resin used in combination with the trifunctional epoxy resin represented by formula (1) refers to any resin having an epoxy group. For example, it refers to bisphenol type Evoquin resin, novolac type epoxy resin, triazine nucleus-containing epoxy resin, etc.

The 7-enol resin curing agent having the structure represented by formula (11) has dicyclopentadiene in its main skeleton, and is a dicyclopentadiene-modified phenol resin curing agent having flexibility and water repellency.

By adjusting the amount of the phenol resin used, the solder stress resistance can be maximized.

In order to obtain the effect of solder stress resistance, it is desirable to use the dicyclopentadiene-modified phenolic resin curing agent represented by formula (U) in an amount of 40% by weight or more, preferably 70% by weight or more of the total amount of the curing agent.

If it is less than 40% by weight, impact resistance and low water absorption will not improve.
Solder stress resistance is insufficient. Furthermore, R,,R in the formula
2 is preferably a hydrogen atom or a methyl group. If the number of carbon atoms in the alkyl group exceeds 2, the reactivity with the epoxy resin tends to decrease and the curability tends to deteriorate.

It is necessary to use a value of n in the range of 0 to 5.

When the value of n is greater than 5, fluidity decreases and moldability deteriorates.

Examples of the curing agent used in combination with the dicyclopentadiene-modified phenolic resin curing agent represented by formula (I[) include phenol novolak resin, cresol novolak resin,
Copolymers of dicyclopentadiene-modified phenol resin and phenol novolak and cresol novolak resins, varaxylene-modified phenol curing agents, acid anhydrides, amine-based curing agents, and the like can be used.

Inorganic fillers used in the present invention include dissolved silica powder,
Examples include spherical silica powder, crystalline silica powder, secondary agglomerated silica powder, porous silica powder, secondary agglomerated silica powder, silica powder obtained by pulverizing porous silica powder, alumina, etc. In the present invention, fused silica powder is particularly preferred. The curing accelerator to be used may be one that promotes the reaction between the epoxy group and the phenolic hydroxyl group, and a wide variety of those commonly used in sealing materials can be used, such as diazabicyclone. Desen (DBU)
, l-riphenylphosphine (TPP), dimethylbenzylamine (BDMA) and 2-methylimidazole (2
MZ) etc. may be used alone or in combination of two or more.

The epoxy resin composition for sealing of the present invention contains an epoxy resin, a curing agent, an inorganic filler, and a curing accelerator as essential components,
In addition, if necessary, silane coupling agents, brominated epoxy resins, flame retardants such as antimony trioxide and hexabromobenzene, coloring agents such as carbon black and red iron, mold release agents such as natural wax and synthetic leather wax, etc. There is no problem in appropriately blending various additives such as low stress additives such as silicone oil and rubber.

In addition, in order to manufacture the epoxy resin composition for sealing of the present invention as a molding material, after sufficiently and uniformly mixing the epoxy resin, curing agent, curing accelerator, filler, and other additives with a mixer etc. Furthermore, it can be melt-kneaded using a heated roll or kneader, cooled, and then crushed to obtain a molding material. These molding materials can be applied to sealing, covering, insulating, etc. electronic or electrical components.

(Example) Example 1 Composition below: 12 parts by weight of trifunctional engineered poquin resin represented by formula (III) 8 parts by weight of orthocresol novolac epoxy resin 6 parts by weight of dicyclopentadiene-modified phenol resin represented by formula (IV) (n-1,2, and the mixing ratio n=1 is 2゜n=2
are mixed at a ratio of 8 parts. ) Phenol novolak resin 5 parts by weight fused silica powder
68.8 parts by weight triphenylphosphine
0, 2 fIfk part carbon black
0.5 parts by weight carnauba wax 0.
5 parts of Ii were mixed at room temperature with a mixer, and the
The molding material was kneaded using a °C 2iM roll, cooled, and then ground.

The obtained molding material was made into a doublet and molded at 175°C% 70kg/cm2.12 using a low-pressure transfer molding machine.
A 6 x 6 Tnm chip was sealed in a 52p package for a solder crack test under 0 second conditions, and a 3 x 6 mm chip was sealed in a 15 ps OP package for a solder moisture resistance test.

Solder crack 1 below for the sealed test element. A test and a solder moisture resistance test were conducted.

Solder cracking test: sealed test element at 85℃,
After processing in an environment of 85% RH for 48 hrs and 72 br, and then immersing it in a solder bath at 250°C for 10 seconds, the occurrence of external cranks was observed under a microscope.

Solder moisture resistance test: sealed test element at 85'0.8
The circuit was processed for 48 hours and 72 hours in an environment of 5% RH, and then immersed in a solder bath at 250°C for 10 seconds, and then subjected to a pressure cooker test (125'0.100% RH) to measure oven failure of the circuit.

The test results are shown in Table 1.

Examples 2 to 5 Molding materials were obtained in the same manner as in Example 1 by blending according to the formulations in Table 1. A sealed molded product for testing was obtained using this molding material, and a solder crack test and a solder moisture resistance test were conducted in the same manner as in Example 1 using this molded product. The test results are shown in Table 1.

Comparative Examples 1 to 4 Molding materials were obtained in the same manner as in Example 1 by blending according to the prescriptions in Table 1. A sealed molded product for testing was obtained using this molding material, and a solder crack test and a solder moisture resistance test were conducted in the same manner as in Example 1 using this molded product. The results are shown in Table 1.

(Effects of the Invention) According to the present invention, it is possible to obtain an Evokin resin composition that has heat resistance, low water absorption, and impact resistance that could not be obtained using conventional techniques, so that rapid temperature changes due to the soldering process can be obtained. It has excellent solder crack resistance when subjected to heat stress caused by heat stress, and also has good moisture resistance, so it is especially suitable for surface mount packages when used for sealing, coating, insulation, etc. of electronic and electrical components. It is suitable for products that require high reliability in highly integrated large-chip ICs mounted on.

Claims (1)

[Claims] (1) (A) Trifunctional epoxy with the structure shown by the following formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼... (I) (In the formula, R_1 to R_1_1 are selected from hydrogen, halogen, and alkyl groups) Epoxy resin (B) containing 50 to 100% by weight of (selected atoms or groups) based on the total amount of epoxy resin ▲ Synchropentadiene-modified phenolic resin with the structure shown by the following formula (II) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼… ...(II) (In the formula, R_1 and R_2 are atoms or groups selected from hydrogen, halogen, and alkyl groups) A curing agent containing 40 to 100% by weight based on the total amount of curing agent (C) Inorganic filler ( D) An epoxy resin composition for semiconductor encapsulation containing a curing accelerator as an essential component.