JPH02274719A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain a semiconductor sealing resin composition excellent in soldering-heat resistance and thermal shock resistance by mixing a specified epoxy resin with a curing agent containing a dicyclopentadiene-modified curing agent, an inorganic filler and a cure accelerator. CONSTITUTION:A resin composition comprising an epoxy resin (A) containing 50 to 100wt.%, based on the total epoxy resin, randomly copolymerized silicone- modified polyepoxy resin obtained by reacting a polyepoxy resin of a structure of formula I (wherein (n) is 0 to 10; X is a mixture of random copolymers in which 0 to 1 group of formula II is present per 2 groups of formula II) with an organopolysiloxane, a curing agent (B) containing 50 to 100wt.% dicyclopentadiene-modified curing agent of formula IV (wherein R is H, an alkyl or a halogen atom), an inorganic filler (C), and a cure accelerator (D).

Description

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

(Prior Art) Semiconductor-related technology has progressed in the direction of improving packaging density due to the recent trend toward lighter, thinner, and smaller devices.

For this reason, the degree of integration of memory is increasing, and the mounting method is shifting from through-hole mounting to surface mounting.

Therefore, the package has changed from the conventional DIP type to a small, thin, surface-mounted flat package, such as SO
P, 50J

In particular, when soldering leads in the surface mounting process, the package is subjected to rapid temperature changes, and the problem of cracks occurring in the package due to this has been attracting attention.

In order to solve these problems, thermoplastic oligomers are added to alleviate the thermal shock during soldering (Japanese Patent Laid-Open No. 62-119).
115849) and the addition of various silicone compounds (
JP-A-62-11585, JP-A-62-1166
54, JP 62-128162), and silicone modification (JP 62-136860)
In all of these methods, cracks occurred in the package during soldering, and it was not possible to obtain an epoxy resin composition for semiconductor encapsulation with excellent reliability.

On the other hand, in order to obtain a heat-resistant epoxy resin composition with excellent soldering heat resistance, a polyfunctional epoxy resin is used as the resin system (
JP-A No. 61-168620) etc. have been studied, but the use of polyfunctional epoxy resins increases crosslinking density and improves heat resistance, especially when exposed to high temperatures such as 200 to 300°C. However, the soldering heat resistance is insufficient, and the thermal shock resistance is extremely unsatisfactory as it becomes hard and brittle.

Therefore, in order to solve these problems, the present inventors
We have already proposed an epoxy resin composition containing a silicone-modified polyfunctional epoxy resin, and have found that these can significantly improve soldering heat resistance and thermal shock resistance.

However, as packages are becoming thinner and chips are becoming larger, the required characteristics for epoxy resin compositions for semiconductor encapsulation are becoming increasingly strict.
Furthermore, there is a demand for resin compositions that have excellent soldering heat resistance and thermal shock resistance.

(Problems to be Solved by the Invention) The present invention has been made to address these problems, and its purpose is to provide an epoxy resin for semiconductor encapsulation that has good soldering heat resistance and thermal shock resistance. An object of the present invention is to provide a composition.

(Means for Solving the Problems) The inventors of the present invention have carried out extensive studies in an effort to obtain an excellent epoxy resin composition for semiconductor encapsulation that has a level of resistance that could not be overcome with conventional techniques. A random copolymerized silicone obtained by reacting a polyfunctional epoxy resin having a structure represented by the following formula (I), which has a good effect of improving soldering heat resistance, and an organopolysiloxane, which has an effect of imparting toughness and low elasticity. A modified polyfunctional epoxy resin is blended in an amount of 50 to 100% by weight based on the total epoxy resin, and in addition, a resin represented by the following formula (n), which has good flexibility and has the effect of improving solder stress resistance and thermal shock resistance, is added. By blending a curing agent containing 50 to 100% by weight of a cyclopentadiene-modified curing agent, an inorganic filler, and a curing accelerator as essential components, soldering heat resistance and thermal shock resistance are improved. It was discovered that the % deviation was significantly improved, and the present invention was completed.

(Function) The random copolymerized silicone-modified polyfunctional epoxy resin used in the present invention is an extremely important component that has the effect of improving both soldering heat resistance and thermal shock resistance.

The organopolysiloxane used as a raw material for these random copolymerized silicone-modified polyfunctional epoxy resins has a functional group that can react with the polyfunctional epoxy resin, and these functional groups include, for example, alkoxy groups, hydroxyl groups, and amino groups. , a hydrosilyl group, and the molecular structure of the organopolysiloxane may be either linear or branched.

Formula (I) reacted with these organopolysiloxanes
The epoxy resin having the structure shown has three or more epoxy groups in one molecule, and has the function of improving soldering heat resistance.

Further, X in the formula is a random copolymer in which (B) is present in a ratio of 0 to 1 to 2 of (A).

If the ratio of (A) to (B) in X is greater than 1, the water absorption will increase, the thermal shock during solder immersion will be large, and the soldering heat resistance will tend to deteriorate.

Furthermore, if the epoxy resin has less than two functional groups, the crosslinking density will not increase, the heat resistance will be poor, and the effect of solder stress resistance will not be obtained.

Further, the value of n needs to be 0 to IO; if it is larger than IO, fluidity tends to decrease and moldability tends to deteriorate.

Although the reaction method of the random copolymerized silicone-modified polyfunctional epoxy resin obtained using these raw materials is not particularly limited, for example, the solder heat resistance of two or more components is significantly improved.

A silicone-modified polyfunctional epoxy resin may be mixed with a conventional epoxy, but in these mixed systems, the silicone-modified polyfunctional epoxy resin should be blended in an amount of 50% by weight or more based on the total amount of epoxy resin. There is a need.

If the blending amount is less than 50% by weight, the solder heat resistance and thermal shock resistance of the resin will decrease, making it insufficient.

The conventional epoxy resin referred to here may be any resin as long as it has two or more epoxy groups in one molecule, such as bisphenol A epoxy resin, bisphenol A epoxy resin, and phenol novolak. Examples include a type epoxy resin, a cresol novolac type epoxy resin, an alicyclic epoxy resin, a triazine nucleus-containing epoxy resin, and modified resins thereof, and these epoxy resins may be used alone or in combination of two or more.

Among these epoxy resins, the epoxy equivalent is 150~
250, the softening point is 60-130°C, and Na
Ionic impurities such as C1- may be produced. An organopolysiloxane having an amino group may be reacted with some epoxy groups of an epoxy resin to form a random copolymer, or an alkenyl group-containing epoxy resin and two or more hydrosilyl groups. There is a method in which a random copolymer is obtained by reacting with an organopolysiloxane having the following.

The random copolymerized silicone-modified multifunctional epoxy resin of the present invention is a product in which an organopolysiloxane and a multifunctional epoxy resin are randomly copolymerized, and the silicone domains are more uniformly dispersed than those obtained by simple block copolymerization. It has excellent moldability, imprintability, moisture resistance, and thermal shock resistance, and since the silicone domain part is composed of a copolymer of silicone and a multifunctional epoxy resin with good heat resistance, it is suitable for multifunctional epoxy resins. When blending a silicone-modified epoxy resin in which the silicone domain is composed of a copolymer of ordinary epoxy resin and silicone, and a silicone-modified phenol resin in which the silicone domain is composed of a copolymer of 7-enol resin and silicone, In comparison, it is preferable to use less.

The dicyclopentadiene-modified curing agent represented by formula (I[) is a polyfunctional polymer having a flexible dicyclopentadiene structure in the molecule, and by using this, it has high flexibility and resistance. An epoxy resin composition with good solder stress resistance can be obtained.

By adjusting the amount of dicyclopentadiene-modified curing agent used, soldering heat resistance can be maximized.

In order to obtain the effect of soldering heat resistance, the amount of dicyclopentadiene must account for 50% by weight or more of the total amount of the curing agent, and more preferably 70% by weight or more.

If it is less than 50% by weight, flexibility will not be improved and soldering heat resistance will be insufficient.

The curing agent other than the dicyclopentadiene-modified curing agent refers to any polymer that undergoes a curing reaction with an epoxy resin, and includes, for example, phenol novolac, talesol novolac resin, and acid anhydride.

The compounding ratio of the epoxy resin and the curing agent is such that the equivalent ratio of the epoxy groups of the epoxy resin to the hydroxyl groups of the curing agent is within the range of 0.5 to 1.5. If the equivalent ratio is less than 0.5 or more than 1.5, the moisture resistance, molding workability, and electrical properties of the cured product will deteriorate, which is not preferred.

Examples of inorganic fillers used in the present invention include crystalline silica, fused silica, alumina, calcium carbonate, talc, mica, and glass fiber.

These may be used alone or in combination of two or more.

Among these, crystalline silica or fused silica is particularly preferably used.

Further, the curing accelerator used in the present invention may be one that promotes the reaction between the epoxy group and the 7-enolic hydroxyl group,
A wide range of materials commonly used for sealing can be used, such as tertiary amines such as BDMA, imidazoles, 1,8-diazabicyclo[5,4,0]
undecene-7 (DBU), triphenylphosphine (
Organic phosphorus compounds such as TPP) can be used alone or in combination of two or more.

The epoxy resin composition for sealing of the present invention is an epoxy resin (a
) 90 parts by weight Brominated bisphenol A epoxy resin (epoxy equivalent: 370, softening point 65°C, bromine content 37%) 10 parts by weight dicyclopentadiene-modified curing agent (e) 60 parts by weight fused silica 490 parts by weight trioxide Antimony 25 parts by weight Silane coupling agent 2 parts by weight Triphenylphosphine
2Mkm carbon black
3 parts by weight of Lunaba Wanx 3 parts by weight were thoroughly mixed at room temperature, then 95-100'c! So 2
The mixture was kneaded with an axial roll, cooled, and then crushed into tablets to obtain the epoxy resin composition for semiconductor encapsulation of the present invention.

This resin was molded using a transfer molding machine (molding pressure conditions: mold temperature 175°C, curing time 2 minutes), and the resulting molded product was cured at 175°C for 13 hours to improve thermal shock resistance and solder heat resistance. The gender was evaluated. The essential components are a greasing agent, a curing agent, an inorganic filler, and a curing accelerator, but in addition to these, flame retardants such as a silane coupling agent, brominated epoxy resin, antimony trioxide, hexabromobenzene, etc. , coloring agents such as carbon black and red iron, mold release agents such as natural wax and synthetic wax, and silicone oil,
Various additives such as low stress additives such as rubber may be appropriately blended.

In addition, in order to manufacture the epoxy resin composition for sealing of the present invention as a molding material, the epoxy resin, curing agent, inorganic filler, curing accelerator, and other additives are thoroughly and uniformly mixed using a mixer or the like. , and further melt-kneaded with a heated roll or kneader, cooled, and then pulverized. These molding materials can be used for sealing, covering, insulating, etc. electronic or electrical components.

(Examples) Example 1 The following random copolymerized silicone-modified polyfunctional epoxy tree composition is shown in Table 1.

Example 2 A semiconductor was produced in the same manner as in Example 1, except that 90 parts by weight of the random copolymerized silicone-modified polyfunctional epoxy resin (a) in Example 1 was changed to 60 parts by weight, and 30 parts by weight of Talesol novolak epoxy resin was further blended. An epoxy resin composition for sealing was obtained.

This material was molded using a transfer molding machine (molding pressure conditions: mold temperature 175°C, curing time 2 minutes), and the resulting molded product was cured at 175°C for 8 hours to achieve thermal shock resistance and soldering heat resistance. was evaluated. The results are shown in Table 1.

Example 3.4 Epoxy resin compositions for semiconductor encapsulation having the compositions shown in Table 1 were obtained in the same manner as in Example 1.

The evaluation results of this epoxy resin composition for semiconductor encapsulation are also shown in Table 1.

Comparative Examples 1 to 3 Epoxy resin compositions for semiconductor encapsulation were obtained in the same manner as in Example 1 by blending according to Table 1.

Table 1 also shows the evaluation results of this epoxy resin composition for semiconductors.

(Left below) *l) Tris(hydroxyalkylphenyl)methane triglycidyl ether represented by formula (III) (n=2
When m = 1 compound is mixed at a ratio of 6, when n = 5, m = 2 compound is mixed at a ratio of 4) and orthoallylphenol, a random copolymerized polyfunctional epoxy resin and a compound of formula (IV) A random copolymerized silicone-modified polyfunctional epoxy resin (epoxy equivalent: 260, softening point: 75 C) *2) Random copolymerized polyfunctional epoxy resin of tris(hydroxyalkylphenyl)methane triglycidyl ether represented by formula (I) and bisphenol A and formula (V
) is reacted with random copolymerized polyfunctional epoxy resin/organopolysiloxane in a 100/20 (weight ratio) random copolymerized silicone-modified polyfunctional epoxy resin (epoxy equivalent: 258
, softening point 72°C) *3) Tris(hydroxyalkylphenyl)methane triglycidyl ether represented by formula (Vl) (n=1.
2.3, and the mixing ratio is 8 for n=1 and L for n=2.
Random copolymerization of polyfunctional Evoquine resin with orthoallylphenol and organopolysiloxane represented by the formula (rV), and random copolymerization of polyfunctional epoxy resin/organopolysiloxane represented by formula (rV). Random copolymerized silicone-modified polyfunctional epoxy resin reacted with polysiloxane in a 100/20 (weight ratio) (epoxy equivalent: 264, softening point: 80°C) *4) Tris(hydroxyalkylphenyl) represented by formula (Vl) ) Random copolymerized polyfunctional epoxy resin of methane triglycidyl ether and bisphenol A and the formula (
A random copolymerized silicone-modified polyfunctional epoxy resin (epoxy equivalent: 26
2. Softening point 79°C) *5) Determined by tris(hydroxyalkylphenyl)methane triglycidyl ether represented by formula (Vl).

The number of molded products with cracks is shown in the table.

*10) 20 molded products (chip size 36mm2, package thickness 1.5mm) were treated under steam at 85°C, 185% RH for 72 hours, and then immersed in a solder bath at 260°C for 10 seconds to determine which molded products had cracks. Determined by the number of pieces.

The number of molded products with cracks is shown in the table.

(Effects of the Invention) According to the present invention, it is possible to obtain an epoxy resin composition that has a high degree of heat resistance and flexibility that could not be obtained using conventional techniques, so that thermal stress caused by sudden temperature changes during soldering can be avoided. Because of its excellent soldering heat resistance and 11i+l silent impact resistance when exposed to heat, it is particularly suitable for use in sealing, covering, and insulating electronic and electrical components. It is suitable for applications where high reliability is required, such as integrated large chip ICs.

*6) Cyclopentadiene-modified curing agent (n-1 to 3) represented by formula (■) *7) Molded product (chip size 35 mm2, package thickness 2
mm) 20 pieces were subjected to temperature cycle test (15000~-1
96°C) and tested for 500 cycles, and the number of molded products that developed cranks was determined.

The number of molded products with cracks is shown in the table.

*8) Temperature cycle test (150°C) of 20 molded products (chip size 36mm2, package thickness 1.5mm)
~-196°C) and 500 cycles of testing, and judgment was made based on the number of molded products with cracks.

The number of molded products with cracks is shown in the table.

*9) After treating 20 molded products (chip size 36 mm2, package thickness 2 mm) under steam at 85°C and 285% RH for 72 hours, immerse them in a solder bath at 260°C for 10 seconds to remove cracked molded products. Number of pieces 20-

Claims (1)

[Claims] (1) (A) A random copolymerized silicone-modified polyfunctional epoxy resin obtained by reacting a polyfunctional epoxy resin having a structure represented by the following formula (I) with an organopolysiloxane in an amount of 50 to 100% based on the total amount of epoxy resin. Epoxy resin containing % by weight▲There are mathematical formulas, chemical formulas, tables, etc.▼……(I) (n is an integer from 0 to 10, and X is the ratio of (A) to 2 and (B) from 0 to 1) A mixture of random copolymers existing in ) (B) A curing agent containing 50 to 100% by weight of a synchropentadiene-modified curing agent with a structure represented by the following formula (II)▲There are mathematical formulas, chemical formulas, tables, etc.▼……( II) (R in the formula represents a hydrogen atom, an alkyl group, and a halogen atom) (C) A resin composition for semiconductor encapsulation, which contains an inorganic filler (D) a curing accelerator as an essential component.