JP2665484B2 - Epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention is excellent in moldability (mold stain, resin burr, molded void, release property), stamping property, moisture resistance, thermal shock resistance, and solder heat resistance. The present invention relates to an epoxy resin composition for semiconductor encapsulation.

(Prior art) In recent years, epoxy resin compositions have been used in large quantities and most commonly used for resin encapsulation of semiconductor elements such as ICs, LSIs, transistors, diodes, and the like, and for resin encapsulation of electronic circuits and the like, from the viewpoint of characteristics and cost. .

However, the demand for encapsulating resin has become stricter with the trend toward mass production of electronic components, lighter and thinner, more integrated, etc., and improvement in moldability, stamping, moisture resistance, thermal shock resistance, and solder heat resistance. In particular, there is a strong demand for an epoxy resin composition having a good balance between improved moldability and stamping properties, moisture resistance, thermal shock resistance, and solder heat resistance.

However, it does not contain additives for improving moisture resistance and thermal shock resistance. Even in ordinary epoxy resin compositions, mold stains, resin burrs, voids, and poor printability are caused by additives such as release agents. Although it tends to occur, additives such as silicone compounds such as silicone oil and silicone rubber, synthetic rubber, and thermoplastic resin must be used to improve moisture resistance and thermal shock resistance. With the use of the agent, mold stain, generation of resin burrs, occurrence of molding voids, and poor printability tend to be further deteriorated.

Mold stains and poor printability are due to the fact that these additive components emerge on the surface of the molded product during molding, and resin burrs and molding voids increase because these components are not compatible with epoxy resins. This is because of poor solubility.

Conventionally, various additives have been studied to improve such problems, and as a resin having an effect on molding processability, stamping property, etc., simply adding silicone and polyalkylene oxide to epoxy resin and general curing agent system. It has already been proposed to add a silicone oil consisting of a copolymer of the above (JP-A-60-13841, JP-B-62-61215). Although the effect was recognized, there was no effect on the thermal shock resistance and the soldering heat resistance, and on the contrary, the moisture resistance was slightly reduced.

Also, an addition polymer of an epoxy resin containing an alkenyl group and the like and an organopolysiloxane was added to the epoxy resin system to improve heat resistance (high Tg), thermal shock resistance and solder heat resistance (crack resistance). Compositions have been proposed (JP-A-62-84147, JP-A-62-212417, etc.), all of which have heat resistance (high Tg), thermal shock resistance and solder heat resistance (crack resistance). The main object of the present invention is to improve the processability and the imprintability of the polymer, which contains a large amount of unreacted and incompatible organopolysiloxane contained in these addition polymers. It was only.

(Object of the Invention) The object of the present invention is to provide moldability (mold stain,
It is an object of the present invention to provide an epoxy resin composition for semiconductor encapsulation, which is excellent in all of resin burrs, molding void release properties), printing properties, moisture resistance, thermal shock resistance, and soldering heat resistance.

(Constitution of the Invention) The present inventors have conducted intensive studies to obtain a well-balanced and excellent epoxy resin composition for semiconductor encapsulation that could not be overcome by the prior art, and as a result, reacted organopolysiloxane and epoxy resin. Both the random copolymerized silicone-modified epoxy resin and the phenolic resin as a curing agent are compatible with each other, and the moldability and processability can be improved by combining a silicone-based copolymer having a specific solubility parameter (hereinafter referred to as SP value). The sealability is further improved as compared with the conventional one. In addition, by improving the adhesion between the lead frame or the IC chip and the sealing resin, a product having excellent solder heat resistance can be obtained.

Further, by combining silicone rubber having good compatibility with the silicone copolymer, liquid synthetic rubber or a mixture of silicone rubber and liquid synthetic rubber, the moldability, stamping property, solder heat resistance and impact resistance are remarkably improved, The inventors have found that a very balanced composition can be obtained, and have completed the present invention.

The organopolysiloxane used as a raw material of the random copolymerized silicone-modified epoxy resin obtained by reacting the organopolysiloxane as the component (A) and the epoxy resin used in the present invention has a functional group capable of reacting with the epoxy resin. These functional groups include, for example, an alkoxy group, a hydroxyl group, an amino group, and a hydrosilyl group. The molecular structure of the organopolysiloxane may be linear or branched.

The epoxy resin to be reacted with these organopolysiloxanes is not particularly limited as long as it has two or more epoxy groups in one molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin Resins, cresol novolak-type epoxy resins, alicyclic epoxy resins, and modified resins thereof, and the like, and these epoxy resins can be used alone or in combination of two or more.

Among these epoxy resins, the epoxy equivalent is 150 to 2
50, those having a softening point of 60 to 130 ° C. and containing as little ionic impurities as possible such as Na ⁺ and Cl ⁻ are preferable.

The reaction method of the random copolymerized silicone-modified epoxy resin using these raw materials is not particularly limited. For example, an organopolysiloxane having two or more amino groups is reacted with a part of epoxy groups of the epoxy resin. To form a random copolymer by 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 epoxy resin of the present invention is obtained by randomly copolymerizing an organopolysiloxane, and since the silicone domains are more uniformly dispersed than those obtained by simply block copolymerizing, the molding processability, stamping property, and moisture resistance are improved. Excellent in heat resistance and thermal shock resistance.

In the present invention, the random copolymerized silicone-modified epoxy resin may be used alone or as a mixture with a conventional epoxy resin. In these mixed systems, the proportion of the random copolymerized silicone-modified epoxy resin is 50% or more. It is necessary.

The phenol resin as the component (B) used in the present invention functions as a curing agent. Examples of these phenolic resins include phenol novolak, cresol novolak, and modified resins thereof, and these can be used alone or in combination of two or more.

The phenolic resin used has a hydroxyl equivalent of 80 to 150,
Those having a softening point of 60 to 120 ° C. and containing as little ionic impurities as possible such as Na ⁺ and Cl ⁻ are preferable.

The SP value as the component (C) used in the present invention is 7 to 9
Is effective in improving the compatibility between epoxy resin and random copolymerized silicone-modified phenolic resin.
It also has the effect of improving solder heat resistance by improving the adhesion between the chip and the sealing resin.

If the SP value of the silicone-based copolymer is less than 7, it becomes too hydrophobic, and the compatibility with the random copolymerized silicone-modified epoxy resin and phenol resin is reduced. If it is more than 9, it becomes too hydrophilic, and the epoxy resin becomes too hydrophilic. The SP value of the silicone-based copolymer is 7 because the compatibility with the silicone-modified phenolic resin is reduced but the compatibility with the random copolymerized silicone-modified phenolic resin is reduced.
Must be within the range of ９9.

The structure of the silicone copolymer is not particularly limited as long as the SP value is within the range of 7 to 9. B; CH _{2 r} OC ₂ H ₄ O _i C ₃ H ₆ O _j CH ₃ However, R _{1 to} R ₆ may be the same group or different groups.

A copolymer of an organopolysiloxane having the structure and an alkylene oxide, or However, R _{1 to} R ₄ may be the same group or different groups.

And a copolymer of an organopolysiloxane having the following structure and styrene.

These silicone copolymers are used within a range of 0.1 to 15% by weight based on the resin component (A + B).

If the amount is less than 0.1% by weight, the effect of improving the solder heat resistance becomes insufficient, and if the amount exceeds 15% by weight, the formability decreases.

Further, the SP value used as the component (D) of the present invention is 7 to
The silicone rubber, the liquid synthetic rubber or the mixture of the silicone rubber and the liquid synthetic rubber in the range of No. 9 is a low-stress agent having good compatibility with the silicone copolymer used as the component (C). When used in combination with the random copolymer silicone-modified epoxy resin and the silicone copolymer of the component (C), all of the moldability, stamping property, solder heat resistance and thermal shock resistance are remarkably improved.

The reason for this is that the compatibility between the random copolymerized silicone-modified epoxy resin (A) improved by the silicone-based copolymer (C) and the other sealing resin components is a silicone rubber, a liquid synthetic rubber, or a liquid synthetic resin. This is because the further improvement is achieved by combining the mixture (D) with the rubber, so that the moldability, stamping property and solder heat resistance are remarkably improved.

Further, the combination of a random copolymerized silicone modified epoxy resin (A) having a low stress effect and silicone rubber, liquid synthetic rubber or a mixture of silicone rubber and liquid synthetic rubber (D) significantly improves thermal shock resistance. Conceivable.

Among those used as the component (D) of the present invention, the silicone rubber is a so-called cured one which is three-dimensionally cross-linked, and is not particularly limited as long as its SP value is in the range of 7 to 9. Silicone rubber has an average particle size of 30μm
In the following, those having a spherical shape (the aspect ratio is 1.5 or less) are desirable, and silicone rubber having reactivity or affinity with epoxy resin or random copolymerized silicone-modified phenolic resin or both of these resins is desirable,
Further, spherical particles having an average particle diameter of 15 μm or less are preferred. Examples of these silicone rubbers include spherical silicone rubbers obtained by interfacially polymerizing an organopolysiloxane having a vinyl group and an organopolysiloxane having a hydrogen group.

These silicone rubbers are used in a range of 1 to 25% by weight based on the resin component (A + B).

If the amount is less than 1% by weight, the effects of improving moldability, stamping properties, thermal shock resistance, and soldering heat resistance will be insufficient. The strength of the material is reduced.

The liquid synthetic rubber is preferably a diene-based rubbery polymer having at least one epoxy group capable of reacting with a curing agent in the molecule, such as epoxidized polybutadiene rubber.

These liquid synthetic rubbers have a resin content (A + B) of 0.1%.
It is used in the range of 5 to 20% by weight.

If the amount of these additives is less than 0.5% by weight, moldability,
The effects of improving the printability, thermal shock resistance, and solder heat resistance become insufficient, and if it exceeds 20% by weight, the hardness at the time of molding and the strength of the molded product decrease.

Further, as the mixture of the silicone rubber and the liquid synthetic rubber, a mixture in which the liquid synthetic rubber component is mixed in the range of 20 to 100 parts with respect to 100 parts of the silicone rubber component is desirable.

The mixture of the silicone rubber and the liquid synthetic rubber is used within a range of 0.5 to 15% by weight based on the resin component (A + B).

If the amount of these additives is less than 0.5% by weight, moldability,
The effects of improving the printability, thermal shock resistance, and solder heat resistance become insufficient, and if the content exceeds 15% by weight, the hardness at the time of molding and the strength of the molded product decrease.

Examples of the inorganic filler as the component (E) 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. You.

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

In the present invention, in addition to the random copolymerized silicone-modified epoxy resin (A), phenolic resin (B), silicone-based copolymer (C), silicone rubber and / or synthetic rubber (D), and inorganic filler (E) BDMA as needed
Curing accelerators such as tertiary amines such as tertiary amines, imidazoles, 1.8-diazabicyclo [5,4,0] undecene-7, and triphenylphosphine; release of natural waxes and synthetic waxes Agents, flame retardants such as hexabromobenzene, decabromobiphenyl ether, antimony trioxide, and coloring agents such as carbon black and red iron,
A silane coupling agent and other thermoplastic resins can be appropriately added and blended.

As a general method for producing the epoxy resin composition for semiconductor encapsulation of the present invention, after sufficiently mixing raw materials of a predetermined composition ratio by a mixer or the like, further melt-mixing treatment by a roll or a kneader or the like. Then, it can be easily performed by cooling, solidifying and pulverizing to an appropriate size.

(Example) Example 1 Random copolymerized silicone modified epoxy resin (A) * ¹
90 parts by weight Brominated phenol novolak epoxy resin (epoxy equivalent 270, softening point 71 ° C, bromine content 30 wt%) 10 〃 Phenol novolak resin (OH equivalent 105, softening point 95 ° C) 4
0 〃 organopolysiloxane and copolymers of alkylene oxide * ³ 5 〃 silicone rubber 6 〃 fused silica 500 〃 trioxide antimony 20 〃 silane coupling agent 2 〃 triphenylphosphine 3 〃 carnauba wax 3 〃 Carbon black 3 〃 The mixture was sufficiently mixed at room temperature, further kneaded at 95 to 100 ° C., cooled, pulverized and tabletted to obtain an epoxy resin composition for semiconductor encapsulation of the present invention.

The stain resistance and resin burr of this material were determined using a transfer molding machine (molding conditions: mold temperature: 175 ° C., curing time: 2 minutes), and the obtained molded product was post-cured at 175 ° C. for 8 hours. The void inside the package, the sealability, the thermal shock resistance, the moisture resistance, and the solder heat resistance were evaluated.

 The results are shown in Table 2.

Example 2 In Example 1, the random copolymerized silicone-modified epoxy resin (a) was replaced with the random copolymerized silicone-modified epoxy resin (b) * ² , and the copolymer of organopolysiloxane and alkylene oxide was replaced with styrene and organopolypropylene. An epoxy resin composition for encapsulating a semiconductor was obtained in the same manner as in Example 1, except that the copolymer was changed to a copolymer with siloxane and the silicone rubber was changed to a liquid synthetic rubber.

The stain resistance and resin burr of this material were determined using a transfer molding machine (molding conditions: mold temperature: 175 ° C., curing time: 2 minutes), and the obtained molded product was post-cured at 175 ° C. for 8 hours. The void inside the package, the sealability, the thermal shock resistance, the moisture resistance, and the solder heat resistance were evaluated.

 The results are shown in Table 2.

Examples 3 to 6 Similarly, epoxy resin compositions for encapsulating semiconductors having the compositions shown in Table 1 were obtained.

Table 2 shows the evaluation results of the epoxy resin composition for semiconductor encapsulation.

Comparative Examples 1 to 8 In the same manner, epoxy resin compositions for semiconductor encapsulation having the compositions shown in Table 1 were obtained.

Table 2 shows the evaluation results of the epoxy resin composition for semiconductor encapsulation.

* ¹ A random copolymerized epoxy resin of an epoxy resin represented by the formula [I] and orthoallylphenol and an organopolysiloxane represented by the formula [II]: 100/20 (weight ratio) ) Random copolymerized silicone modified epoxy resin (epoxy equivalent 250, softening point 75 ℃) However, m / n + m = 0.08 * ² A random copolymerized epoxy resin comprising a copolymerized epoxy resin of bisphenol A and an epoxy resin of formula [III] and an organopolysiloxane of formula [IV]
Random copolymerized silicone-modified epoxy resin obtained by reacting organopolysiloxane at 100/20 (weight ratio) (epoxy equivalent: 265, softening point: 77 ° C) However, m / n + m = 0.06 * ³ Copolymer represented by formula [V] Y; CH _{2 3} OC ₂ H ₄ O ₃₀ C ₃ H ₆ O ₃₀ CH ₃ * ⁴ Copolymer represented by the formula [VI] * ⁵ Spherical solid silicone rubber (average particle size of 15) obtained by three-dimensionally cross-linking by interfacial polymerization of ^5- vinyl group-containing organopolysiloxane and hydrogen-containing organopolysiloxane.
μ, spherical, SP value 7.5) * ⁶ Oxidizes some of the unsaturated double bonds of butadiene rubber,
Epoxidized liquid epoxidized polybutadiene rubber (oxygen content 7%, viscosity 5500 poise, SP value 8.4) * Judgment by the number of molding shots until type ⁷ fogging occurs.

* ⁸ The length of the resin burr at the vent of the obtained molded product was measured.

* ⁹ Using the molded product of the 10th shot, when the cellophane tape is peeled off after marking, the judgment is based on the number of stamps. In the table, the number of peeled seals out of 50 molded products is shown.

* ¹⁰ Twenty molded products (post-curing 175 ° C, 8Hrs) are subjected to a temperature cycle test (150 ° C to -65 ° C) and tested for 500 cycles. Judgment is based on the number of cracks. Molded products in the table
Shows the number of cracks out of 20.

* ¹¹ 100 molded products (post-curing 175 ° C, 8Hrs) were subjected to a 1000-hour moisture resistance test in high-pressure steam at 120 ° C, and judged based on the number of defective products. The table shows the number of defective products out of 100 molded products.

* ^Twelve 16 molded products (post-cured 175 ° C, 8Hrs) were treated in 85 ° C, 85% water vapor for 72 hours, then immersed in a 260 ° C solder bath for 10 seconds, and judged by the number of generated syrac. The table shows the number of cracks in 16 molded products.

(Effects of the Invention) By combining a silicone-based copolymer having a solubility parameter (SP value) compatible with both a random copolymerized silicone-modified epoxy resin and a random copolymerized silicone-modified phenolic resin, moldability and printability are improved. Improved solder heat resistance due to improved adhesiveness, and further molding by combining silicone rubber, liquid synthetic rubber, or a mixture of silicone rubber and liquid synthetic rubber with good compatibility with the silicone copolymer. An epoxy resin composition for semiconductor encapsulation with improved processability, stamping properties, and solder heat resistance, and with significantly improved impact resistance is obtained.

This epoxy resin composition for semiconductor encapsulation is excellent in impact resistance, so it can seal large chips, and it has very good heat resistance in soldering, so it is highly reliable even when used for thin packages. It is.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Reference number in the agency FI Technical display location // (C08L 63/00 83:04)

Claims (3)

(57) [Claims] 1. A random copolymerized silicone-modified epoxy resin obtained by reacting an organopolysiloxane with an epoxy resin. 2. A phenolic resin curing agent. 3. A silicone copolymer having an SP value in the range of 7 to 9. Incorporation (D) Silicone rubber having an SP value in the range of 7 to 9 (E) Inorganic filler as an essential component, 0.1 to 15% by weight of silicone copolymer (C) based on resin component (A + B), An epoxy resin composition containing 1 to 25% by weight of a silicone rubber (D). 2. A random copolymerized silicone-modified epoxy resin obtained by reacting an organopolysiloxane with an epoxy resin. 2. A phenolic resin curing agent. 2. A silicone copolymer having an SP value in the range of 7 to 9. (D) Liquid synthetic rubber having an SP value in the range of 7 to 9 (E) Inorganic filler is an essential component, and the silicone copolymer (C) is 0.1 to 15% by weight based on the resin component (A + B). An epoxy resin composition comprising 0.5 to 20% by weight of a liquid synthetic rubber (D). 3. A random copolymerized silicone modified epoxy resin obtained by reacting an organopolysiloxane with an epoxy resin. 2. A phenolic resin curing agent. 3. A silicone copolymer having an SP value in the range of 7 to 9. Combination (D) Mixture of silicone rubber and liquid synthetic rubber having an SP value in the range of 7 to 9 (E) Inorganic filler is an essential component, and silicone copolymer (C) is added to resin component (A + B). An epoxy resin composition comprising 0.1 to 15% by weight, and 0.5 to 20% by weight of a mixture (D) of a silicone rubber and a liquid synthetic rubber.