JP2641277B2 - 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.

In addition, as an additive, a block polymer comprising an aromatic polymer and an organopolysiloxane has been proposed (Japanese Patent Application Laid-Open No. 58-21417). Although the improvement is seen, the concentration of the silicone part is uneven due to the block copolymer,
The compatibility with other components was poor and unsatisfactory, and almost no effect was observed on the solder heat resistance.

Further, a composition has been proposed in which at least one of a phenol resin modified with an organopolysiloxane is an essential component in the same manner as the phenol novolak type epoxy resin modified with an organopolysiloxane, and a phenol novolak type epoxy resin and a phenol resin are optional components. (Japanese Unexamined Patent Publication No. Sho 62-136860) also aims to improve the moisture resistance after solder immersion, and to make the whole resin composition hydrophobic. It is sacrificed and lacks the balance that is the object of the present invention.

(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. Combining a silicone copolymer having a specific solubility parameter (hereinafter referred to as SP value) that is compatible with both the random copolymerized silicone modified epoxy resin and the random copolymerized silicone modified phenol novolak resin as a curing agent Molding processability and stamping properties are further improved compared to conventional products, and in addition to this, products with excellent solder heat resistance are obtained by improving the adhesion between the lead frame or IC chip and the sealing resin. Can be

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 random copolymerized silicone-modified phenol novolak resin as the component (B) used in the present invention functions as a curing agent.

The organopolysiloxane used as a raw material of these random copolymerized silicone-modified phenol novolak resins has a functional group capable of reacting with the phenol novolak resin, and examples of these functional groups include an epoxy group, an alkoxy group, and a hydrosilyl group. And
The molecular structure of the organopolysiloxane may be linear or branched.

Examples of the phenol novolak resin to be reacted with these organopolysiloxanes include phenol novolak, cresol novolak, and modified resins thereof, and these can be used alone or in combination of two or more.

The phenol novolak resin used has a hydroxyl equivalent
It is preferable that the resin has a softening point of 60 to 120 ° C. and a minimum of ionic impurities such as Na ⁺ and Cl ⁻ .

The random copolymerized silicone-modified phenol novolak resin of the present invention is obtained by reacting an organopolysiloxane having a reactive functional group with a phenol novolak resin in the presence of a catalyst such as a tertiary amine or an organic phosphine compound.

The random copolymerized silicone-modified phenol novolak resin of the present invention is obtained by randomly copolymerizing an organopolysiloxane, and since silicone domains are more uniformly dispersed than those obtained by simply block copolymerization, moldability, stamping properties, Excellent in moisture resistance and thermal shock resistance.

In the present invention, the random copolymerized silicone-modified phenolic resin curing agent may be used alone or as a mixture with another phenol novolak-based curing agent, but in these mixed systems, the random copolymerized silicone-modified phenolic resin is used. It is desirable to use 50% by weight or more of the curing agent system.

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, the resin becomes too hydrophobic, and the compatibility with the epoxy resin and the random copolymerized silicone-modified phenol resin is reduced. If the SP value is more than 9, the resin becomes too hydrophilic, and the epoxy resin becomes too hydrophilic. Is improved, but the compatibility with the random copolymerized silicone-modified phenolic resin is reduced, so that the SP value of the silicone-based copolymer is 7 to
9 is required.

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 in the range of 0.1 to 12% by weight based on the resin component (A + B).

If the addition amount is less than 0.1% by weight, the effect of improving the solder heat resistance becomes insufficient, and if it exceeds 12% by weight, the moldability 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). Molding processability, stamping properties, solder heat resistance, thermal shock resistance when used in combination with a random copolymerized silicone modified epoxy resin and a random copolymerized silicone modified phenolic resin of component (B) and a silicone copolymer of component (C). Both properties are significantly improved.

The reason is that the compatibility between the random copolymerized silicone-modified epoxy resin (A) improved by the silicone-based copolymer (C) and the random copolymerized silicone-modified phenolic resin of the component (B) is silicone rubber or liquid synthetic rubber. Or a mixture of silicone rubber and liquid synthetic rubber (D)
Is further improved by combining them, so that the moldability, stamping property and solder heat resistance are remarkably improved.

Also, a random copolymerized silicone-modified epoxy resin (A) and a random copolymerized silicone-modified phenolic resin (B) having a low stress effect are combined with silicone rubber, liquid synthetic rubber or a mixture of silicone rubber and liquid synthetic rubber (D). It is considered that the thermal shock resistance is significantly improved by this.

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 a silicone rubber having reactivity or affinity with both or one of the random copolymerized silicone modified epoxy resin and the random copolymerized silicone modified phenolic resin is preferable. Desirably, those having a spherical shape with an average particle diameter of 15 μm or less are preferable. 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 the range of 1 to 20% 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 15% 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 the content exceeds 15% 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 in the range of 0.5 to 13% 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 13% by weight, the hardness at the time of molding and the strength of the molded product are reduced.

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, a random copolymerized silicone-modified epoxy resin (A), a random copolymerized silicone-modified phenolic resin (B), a silicone-based copolymer (C), a silicone rubber and / or a synthetic rubber (D), and an inorganic filler ( In addition to E), if necessary, curing accelerators such as tertiary amines such as BDMA, imidazoles, and organic phosphorus compounds such as 1.8-diazabicyclo [5,4,0] undecene-7 and triphenylphosphine; Release agents such as waxes and synthetic waxes, flame retardants such as hexabromobenzene, decabromobiphenyl ether and antimony trioxide, coloring agents such as carbon black and red iron oxide, silane coupling agents and other thermoplastic resins are added as appropriate. Can be 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: 370, softening point: 65 ° C, bromine content: 37 wt%) 10 ラ ン ダ ム Randomly copolymerized silicone modified phenolic resin (c) *
³ 50 〃 organopolysiloxane a copolymer * ⁶ 6 〃 silicone rubber 7 〃 fused silica 470 〃 trioxide 25 〃 silane coupling agent 2 〃 1,8-diazabicyclo [5.4.0] undecene of an alkylene oxide -73カ ル Carnauba wax 3 〃carbon black 3 十分 was sufficiently mixed at room temperature, kneaded at 95 to 100 ° C., cooled, pulverized and tableted to obtain an epoxy resin composition for semiconductor encapsulation of the present invention. Mold stain of this material,
Transfer molding machine for resin burrs (molding conditions: mold temperature
(175 ° C, curing time: 2 minutes), and the resulting molded article is post-cured at 175 ° C for 4 hours to evaluate voids, marking properties, thermal shock resistance, moisture resistance and solder heat resistance inside the package. did.

 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 random copolymerized silicone-modified phenolic resin (c) was replaced with the random copolymerized silicone-modified phenolic resin. (d) * ^4, changing a copolymer of an organopolysiloxane with alkylene oxide to copolymer * ⁷ of styrene and organopolysiloxane, except that further changing the silicone rubber 7 parts by weight 20 parts by weight example In the same manner as in Example 1, an epoxy resin composition for semiconductor encapsulation was obtained. 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. Voids inside the package, marking, thermal shock resistance,
The moisture resistance and solder heat resistance were evaluated.

 The results are shown in Table 2.

Examples 3 to 9 Similarly, 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.

Comparative Examples 1 to 12 Epoxy resin compositions for semiconductor encapsulation having the compositions shown in Table 1 were obtained in the same manner.

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 78 ° C) However, m / n + m = 0.09 * 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 260, softening point 75 ° C) However, m / n + m = 0.05 * ³ A random copolymerized novolak of a phenol represented by the formula [V] and an orthoallylphenol and an organopolysiloxane represented by the formula [VI] in a random copolymerized novolak / organopolysiloxane ratio of 100/20 (weight ratio). Reacted random copolymerized silicone modified phenolic resin (OH equivalent 125, softening point 95 ° C) However, m / n + m = 0.08 * ⁴ phenol novolak resin (OH equivalent 110, softening point 95
C.) and an organopolysiloxane represented by the formula [VII] are reacted at a phenol novolak resin / organopolysiloxane ratio of 100/20 (weight ratio) (OH equivalent 127, softening point 97 ℃) * ⁵ phenol novolak resin (OH equivalent 106, softening point 100
° C) and a phenolic novolak resin / dimethylsiloxane represented by the formula [VIII] at a ratio of 100 / 33.3 (weight ratio) to a random copolymerized silicone-modified phenolic resin (OH equivalent: 157;
Softening point 96 ° C) * ⁶ Copolymer represented by formula [IX] Y; CH _{2 3} OC ₂ H ₄ O ₂₀ C ₃ H ₆ O ₂₀ CH ₃ * ⁷ Copolymer represented by the formula [X] * ⁸ Polydimethylsiloxane represented by formula [XI] * ^{9 A} spherical solid silicone rubber (average particle size of 15
μ, spherical, SP value 7.5) * ¹⁰ 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) * Determined by the number of molding shots until type ¹¹ fogging occurs.

* ¹² Measure the length of the resin burr at the vent of the obtained molded product.

* ¹³ Judged by the number of stamps when the cellophane tape was peeled off after stamping using the molded product of the 10th shot. In the table, the number of peeled seals out of 50 molded products is shown.

* ¹⁴ Twenty molded products (post-curing 175 ° C, 8Hrs) are subjected to a temperature cycle test (150 ° C to -65 ° C), and are 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.

* ¹⁵ 100 molded products (post-cured 175 ° C, 8Hrs) were subjected to a 1000-hour humidity 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.

* ^{16 16} molded products (post-curing 175 ° C, 8Hrs) were treated in 85%, 85% steam 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 (A) an organopolysiloxane with an epoxy resin. (B) A random copolymerized silicone modified phenolic resin curing agent obtained by reacting an organopolysiloxane with a phenol novolak resin. (C) a silicone copolymer having an SP value in the range of 7 to 9; (D) a silicone rubber having an SP value in the range of 7 to 9; (E) an inorganic filler as an essential component; and a resin component (A + B). An epoxy resin composition containing 0.1 to 12% by weight of a silicone copolymer (C) and 1 to 20% by weight of a silicone rubber (D). 2. A random copolymerized silicone modified epoxy resin obtained by reacting (A) an organopolysiloxane with an epoxy resin. (B) A random copolymerized silicone modified phenolic resin curing agent obtained by reacting an organopolysiloxane with a phenol novolak resin. (C) a silicone copolymer having an SP value in the range of 7 to 9 (D) a liquid synthetic rubber having an SP value in the range of 7 to 9 (E) an inorganic filler as an essential component, and a resin component (A + B) An epoxy resin composition comprising 0.1 to 12% by weight of a silicone-based copolymer (C) and 0.5 to 15% by weight of a liquid synthetic rubber (D), based on the weight of the epoxy resin composition. 3. A random copolymerized silicone-modified epoxy resin obtained by reacting an organopolysiloxane with an epoxy resin (B) A random copolymerized silicone-modified phenolic resin curing agent obtained by reacting an organopolysiloxane with a phenol novolak resin (C) a silicone copolymer having an SP value in the range of 7 to 9; (D) a mixture of a silicone rubber and a liquid synthetic rubber having an SP value in the range of 7 to 9; An epoxy resin composition comprising 0.1 to 12% by weight of a silicone copolymer (C) and 0.5 to 13% by weight of a liquid synthetic rubber (D) based on a resin component (A + B).