JPH03718A - Resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin compsn. for sealing a semiconductor with good soldering heat resistance and heat shock resistance by compounding a polyfunctional epoxy resin modified with a randomly copolymerized silicon and a p-xylene-modified curing agent. CONSTITUTION:A resin compsn. comprising an epoxy resin (A) contg. 50-100wt.%, based on the total amt. of the epoxy resin, randomly copolymerized silicone-modified polyfunctional epoxy resin prepd. by reacting a polyfunctional epoxy resin having a structure of formula I with an organopolysiloxane, a curing agent (B) contg. 50-100wt.% p-xylene-modified curing agent having a structure of formula IV, an inorg. filler (C) and a curing accelerator (D). In the formulas, n is 0-10; X is a mixture of random copolymers wherein formulas II and III exist at a ratio of 2:0-1. When this compsn. is used for sealing, coating, insulation, etc., for electronic and electric parts, it is especially suitable for such uses where reliability is highly required as a highly-integrated large chip IC mounted on a package for surface packaging.

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.

First, the degree of integration of memory is increasing, and the mounting method is moving from through-hole mounting to surface mounting.

Therefore, the package has changed from the conventional DIP type to a small, thin surface-mounted 7-rat package, such as a 5O
With the shift to PSSOJ and PLCC, problems such as occurrence of cranks due to internal stress and a decrease in moisture resistance due to these cracks are becoming more prevalent.

In particular, the package is subject to rapid temperature changes during lead soldering in the surface mounting process, and the problem of cracks occurring in the package due to this is attracting attention.

In order to solve these problems, thermoplastic oligomers are added to alleviate the thermal shock during soldering (Japanese Unexamined Patent Application Publication 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)
Although these methods have been used to deal with the problem, cracks occur in the package during soldering, and it has not been possible to obtain a highly reliable epoxy resin composition for semiconductor encapsulation.
;.

On the other hand, in order to obtain a heat-resistant epoxy resin composition with excellent soldering heat resistance, the use of a polyfunctional epoxy resin as the resin system (Japanese Patent Application Laid-Open No. 168620/1983) has been considered; The use of resin increases crosslinking density and improves heat resistance, but especially when exposed to high temperatures such as 200 to 300°C, soldering heat resistance is insufficient, and it becomes hard and brittle, resulting in poor thermal shock resistance. were extremely unsatisfactory◎ Therefore, the present inventors, in order to solve these problems,
We have already proposed an epoxy resin composition containing a silicone-modified polyfunctional Evoquine 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 present inventors conducted extensive studies in an effort to obtain an excellent, well-balanced epoxy resin composition for semiconductor encapsulation that could not be overcome using conventional techniques. A random copolymerized silicone-modified multifunctional epoxy resin made by reacting with the following polysiloxane, which has the effect of improving soldering heat resistance, is blended in an amount of 50 to 100% by weight based on the total epoxy resin. A curing agent containing 50 to 100% by weight of a paraxylene-modified curing agent represented by the following formula (II) that has the effect of improving stress resistance and thermal shock resistance, an inorganic filler, and a curing accelerator are blended as essential components. It was discovered that both solder heat resistance and thermal shock resistance were significantly improved by this, and this led to the completion of the present invention.

(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 above has three or more epoxy groups in one molecule, and has the function of improving soldering heat resistance.

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

If the ratio of (A) to X (B) is greater than 1 to 2, 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 between θ and lO, and if it is larger than lO, fluidity tends to decrease and moldability tends to deteriorate.

The reaction method of the random copolymerized silicone-modified polyfunctional epoxy resin obtained using these raw materials is not particularly limited, but for example, an organopolysiloxane having two or more amino groups and a part of the epoxy resin There are methods such as reacting groups to obtain a random copolymer, or reacting an alkenyl group-containing epoxy resin with an organopolysiloxane having two or more hydrosilyl groups to obtain a random copolymer.

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 a normal epoxy resin and silicone, and a silicone-modified 7-ninol resin in which the silicone domain is composed of a copolymer of a phenol resin and silicone. Soldering heat resistance is significantly improved compared to .

A silicone-modified polyfunctional epoxy resin may be mixed with a conventional epoxy resin, but in these mixed systems, the silicone-modified polyfunctional epoxy resin is added at a ratio of 50% to the total amount of epoxy resin. It is necessary to blend i amount % or more.

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

The conventional epoxy resin mentioned 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 F epoxy resin, phenol novolac type. Examples include epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, triazine nucleus-containing epoxy resins, 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, a softening point of 60 to 130°C, and Na+
It is preferable that the amount of ionic impurities such as CF is as small as possible.

The paraxylene-modified curing agent represented by the formula (If) has a methylene group of -CH+C
It has a structure in which l-1= is substituted, and by using this, visibility, impact resistance, and low water absorption can be improved, so an epoxy resin composition with good soldering heat resistance can be obtained. .

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

In order to achieve the effect of soldering heat resistance, the amount of the paraxylene-modified curing agent 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 paraxylene-modified curing agent refers to any polymer that undergoes a curing reaction with an epoxy resin, and includes, for example, phenol novolak, 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 preferable.

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 any one as long as it promotes the reaction between the epoxy group and the phenolic hydroxyl group.
A wide range of materials commonly used for sealing can be used, such as tertiary amines such as BDMA, imidazoles, l,8-diazabicyclo[5,4,Q]
Organic phosphorus compounds such as Townsen-7 (DBII) and triphenylphosphine (TPP) can 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 to these, silane coupling agents, brominated epoxy resins, antimony trioxide, flame retardants such as hexabromobenzene, coloring agents such as carbon black and red iron, natural waxes, synthetic waxes, and silicone oils may be added as necessary. , 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.

(Example) Example 1 Random copolymerized silicone-modified polyfunctional 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 paraxylene-modified curing agent (e) 60 parts by weight fused silica 490! Parts by weight Antimony trioxide 25 parts by weight Silane coupling agent 2 parts by weight DBU'
2 parts by weight carbon black
3 parts by weight carnauba wax 3
Parts by weight were thoroughly mixed at room temperature, and then heated to 95-100°C for 2 hours.
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 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 improve thermal shock resistance and soldering heat resistance. evaluated. The results are shown in Table 1.

Example 2 Same as Example 1 except that 9.0 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 novolac epoxy resin was further blended. An epoxy resin composition for semiconductor encapsulation 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 improve thermal shock resistance and soldering heat resistance. evaluated. The results are shown in Table 1.

Examples 3 and 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 I by blending according to Table 1.

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

(Left below) *l) Tris(hydroxyalkylphenyl)methane triglycidyl ether (n-2
A random copolymerized polyfunctional epoxy resin with orthoallylphenol and an organopolymer represented by the formula (IV). A random copolymerized silicone-modified polyfunctional epoxy resin made by reacting siloxane with a random copolymerized polyfunctional epoxy resin/organopolysiloxane at a ratio of 100/20 (weight ratio) (epoxy equivalent fk260, softening point 75°C) *2) A random copolymerization polyfunctional epoxy resin of tris(hydroxyalkylphenyl)methane triglycidyl ether and bisphenol A represented by the formula (I[[) and an organopolysiloxane represented by the formula (V)] Random copolymerized silicone-modified polyfunctional epoxy resin (epoxy equivalent: 258, softening point: 72°C) obtained by reacting epoxy resin/organopolysiloxane at a ratio of 100/20 (weight ratio) *3) Tris ( hydroxyalkylphenyl)methane triglycidyl ether (n=1.
2.3, and the mixing ratio is 8 for n=1, 1 for n-2,
A random copolymerized polyfunctional epoxy resin with orthoallylphenol and an organopolysiloxane represented by the formula (rV) are mixed into a random copolymerized polyfunctional epoxy resin/organopolysiloxane represented by the formula (rV). Random copolymerized silicone-modified polyfunctional epoxy resin reacted with polysiloxane at a ratio of 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 formula (
A random copolymerized silicone-modified polyfunctional epoxy resin (epoxy equivalent: 26
2. Softening point: 79°C) *5) Tris(hydroxyalkylphenyl)methane triglycidyl ether represented by formula (VI)) *6) Barraxylene-modified curing agent represented by formula (■) (n: 3-5. i per 0H 185. Softening point 80℃) *7
) Molded product (chip size 36mm, package thickness 2m)
m) Temperature cycle test (150°C to -19°C) of 20 pieces.
6°C) for 500 cycles, and the number of molded products with cracks was determined.

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

*8) Molded product (chip size 36m, package thickness 1)
．． 5rl! m) Temperature cycle test (150°) of 20 pieces
℃ to -196℃), and was subjected to 500 cycles of testing and determined by the number of molded products with cracks.

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

*9) 20 molded products (chip size 36 mm, 1 package thickness 2 mm) 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. Determined by the number of items.

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

*1O) 20 molded products (chip size 36mm", package thickness 1.5mm) were treated under steam at 85°C and 85% RH for 72 hours, and then immersed in a solder bath at 260°C for 10 seconds to prevent cracks from forming. Determined by the number of molded products.

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

(Advantageous Effects) 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. It has excellent soldering heat resistance and thermal shock resistance when subjected to stress, so it is used for sealing electronic and electrical components.
When used for coating, insulation, etc., it is particularly suitable for applications that require high reliability, such as highly integrated large chip ICs mounted on surface mount packages.

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) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼... (A) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (B) (n is an integer from 0 to 10, and X is a mixture of random copolymers in which (A) is present in a ratio of 2 to 0 to 1 (B)) A curing agent containing 50 to 100% by weight of a paraxylene-modified curing agent with a structure of Resin composition for semiconductor encapsulation.