JPH0931161A - Liquid epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compsn. low in viscosity, excellent in workability and adhesion, high in glass transition temp., and capable of forming a cure product having good stress properties by using a specific epoxy resin, a curing agent, a curing accelerator, and a specific copolymer. SOLUTION: (A) an epoxy resin of formula I is blended with (B) dicyandiamide in an amt. of 2 to 20 pts.wt. per 100 pts.wt. components (A)+(D), (C) a curing accelerator in an amt. of 0.01 to 10 pts.wt. per 100 pts.wt. components (A)+(B), and (D) a copolymer obtd. by an addn. reaction of alkenyl groups of an alkenyl group-contg. epoxy resin or an alkenyl group-contg. phenolic resin with SiH groups of an organohydrogenpolysiloxane of formula II (R<1> is a monovalent hydrocarbon; 0.002<=a<=0.1; 1.8<=b<=2.2; and 1.8<a+b<=2.3) having 20 to 400 silicon atoms and 1 to 5 SiH groups per molecule in an amt. of 0.5 to 20 pts.wt. as the organopolysiloxane in the copolymer per 100 pts.wt. components (A)+(B)+(C)+(D) to obtain a liq. epoxy resin compsn.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid epoxy resin composition which is preferably used as an adhesive for semiconductor elements, a sealing material for semiconductor elements, and the like. More specifically, it has low viscosity and excellent workability, and The present invention relates to a liquid epoxy resin composition having excellent adhesiveness, a high glass transition temperature, and a cured product having good stress characteristics.

[0002]

2. Description of the Related Art Conventionally, as a method of bonding a semiconductor element to a lead frame in manufacturing a semiconductor device, silver powder is dispersed in an organic material such as epoxy resin or polyimide resin. The silver paste thus prepared is used as an adhesive. In addition, recently, there is an increasing tendency to use a copper-based lead frame for the purpose of increasing the size of a semiconductor device and improving the heat dissipation of the device.

In this case, when the paste is hardened and cooled at a high temperature of 150 to 250 ° C., the warp of the semiconductor element increases due to thermal stress, and the thermal history during wire bonding causes cracks not only in the semiconductor element but also in the die bond material. It is likely to occur, and has a great influence particularly in a semiconductor device that requires high precision and reliability.

Therefore, in order to improve the above-mentioned problems, studies have been made to prevent warpage by adding phenoxy resin or epoxidized liquid polybutadiene to the paste to reduce the elasticity. Since the liquid rubber of (1) becomes hard at low temperature and loses elasticity, it has not been able to exhibit a sufficient effect in the low temperature region.

On the other hand, the present inventors have made various proposals to give an epoxy resin composition having excellent stress characteristics by adding a silicone-modified phenol resin or epoxy resin to the epoxy resin composition ( Japanese Patent Examination 3-645
No. 32, Japanese Examined Patent Publication No. 63-6084, No. 63-60070
No. 63-60069).

Further, a liquid epoxy resin composition containing a bisphenol A type epoxy resin which is liquid at room temperature using this type of silicone-modified resin has also been proposed (Japanese Patent Publication No. 5-73123). 6-602
No. 32).

However, although the above-mentioned proposal has made it possible to improve the stress characteristics of the liquid epoxy resin composition, when the inorganic filler (filler) is highly filled to further improve the stress characteristics, the viscosity of the resulting composition is increased. Is too high,
It has been found that the workability is deteriorated and the wettability with the base material is deteriorated, which may cause deterioration in adhesiveness and reliability. In this case, it is possible to easily reduce the viscosity by adding a reactive diluent or solvent to the liquid epoxy resin composition, but this method reduces the glass transition temperature and shrinks with evaporation of the solvent or diluent. This sometimes caused cracks and increased stress.

Further, the above liquid epoxy resin composition usually uses an acid anhydride as a curing agent, and this oxidizing agent is easily hydrolyzed by water to generate an acid.
There was a problem in moisture resistance.

The present invention has been made in view of the above circumstances, and provides a cured product having a low viscosity, excellent workability, excellent adhesion, a high glass transition temperature, few cracks, and good stress characteristics. It is an object to provide a liquid epoxy resin composition to be given.

[0010]

Means for Solving the Problems and Modes for Carrying Out the Invention The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, as a result of the epoxy resin, a specific epoxy resin represented by the following formula (1) with use, the epoxy resin composition using dicyandiamide as a curing agent, further alkenyl groups and the following average compositional formula alkenyl group-containing epoxy resin or alkenyl group-containing phenol resin ^{_{(2) H a R 1 b}} SiO {4- _{(a + b)} / 2} (2) (In the formula, R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0.002 ≦ a ≦ 0.1 and 1.8. ≤b≤
It is a number that satisfies 2.2, 1.8 <a + b ≦ 2.3. ), The number of silicon atoms in one molecule is 20 to 40
0, the liquid epoxy resin composition obtained by blending the copolymer by addition reaction with the SiH group of the organohydrogenpolysiloxane in which the number of SiH groups is 1 to 5 has a low viscosity, It has been found that it has excellent properties, a high glass transition temperature, and excellent stress properties.

[0011]

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That is, by blending the above-mentioned copolymer with the above-mentioned specific epoxy resin and curing agent, this copolymer effectively acts as a low stress agent, and a large amount of inorganic filler is added. Also does not cause an increase in viscosity and is excellent in workability. In addition, by using dicyandiamide as a curing agent, deterioration of moisture resistance can be suppressed, and the obtained liquid epoxy resin composition has low stress. While maintaining good properties, it provides a cured product with excellent moisture resistance, high glass transition temperature, few cracks, and excellent adhesiveness. Therefore, an adhesive for semiconductor devices and a semiconductor device The present invention has been completed by finding that a highly reliable semiconductor device, which is suitable as an encapsulating material for automobiles, can be obtained.

Therefore, the present invention provides (A) an epoxy resin represented by the above structural formula (1), (B) dicyandiamide, (C) a curing accelerator, (D) an alkenyl group-containing epoxy resin or an alkenyl group-containing phenol resin. Of the organohydrogenpolysiloxane having 20 to 400 silicon atoms and 1 to 5 SiH groups in one molecule represented by the above alkenyl group and the average composition formula (2).
A liquid epoxy resin composition comprising a copolymer obtained by an addition reaction with a group.

Hereinafter, the present invention will be described in more detail.
The component (A) of the liquid epoxy resin composition of the present invention is an epoxy resin represented by the following formula (1).

[0015]

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In this case, it is preferable that the epoxy resin has a monomer component of 90% or more, particularly 95% or more, but the epoxy resin may partially contain an oligomer in which monomers react with each other. If the amount of the monomer component is less than 90%, the resin viscosity will be high, and the viscosity of the composition will be high, resulting in poor workability. The viscosity of the epoxy resin of the present invention at room temperature (25 ° C) is 500 to 900c.
It is preferably p, particularly 550 to 750 cp. If the viscosity at room temperature is higher than 900 cp, it may be difficult to highly fill the composition with various inorganic fillers to be blended in order to reduce the expansion coefficient of the cured product and improve the thermal conductivity. is there. The epoxy equivalent is 92 to 1.
It is preferably 10, especially 95 to 105. When the epoxy equivalent is more than 110, the epoxy resin has a high molecular weight (that is, a high viscosity), and the same disadvantages as described above may occur. Further, the total chlorine content of the epoxy resin is 1500 ppm or less, particularly 100 to 1000 pp.
m, further, the extracted water chlorine in 20 hours at 120% at 50% epoxy resin concentration is 5 ppm or less, especially 1 to 3
It is preferably ppm. Total chlorine content is 1500
If it is less than ppm and the amount of extracted water chlorine is more than 5 ppm, the moisture resistance reliability of the semiconductor may decrease.

As the epoxy resin used in the present invention, in addition to the above epoxy resin, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin,
Phenol novolac type epoxy resin, cresol novolac type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, cyclopentadiene type epoxy resin and the like are exemplified, and among these, an epoxy resin which is liquid at room temperature is preferable, and one or more of them is preferable. You may use it in mixture of 2 or more types.

The epoxy resin represented by the above formula (1) is preferably contained in an amount of 20% by weight or more, particularly 40 to 100% by weight, based on the whole epoxy resin, and if less than 20% by weight, the object of the present invention is not achieved. There are cases.

The component (B) is dicyandiamide, which acts as a curing agent for the component (A). This dicyandiamide is H ₂ NC (= NH) -NHC
A cyanoguanidine represented by N, and a conventionally known one can be used. In this case, since the melting point of dicyandiamide is as high as 209 ° C., it is preferable to pulverize it with a pulverizer to 200 mesh or less, particularly 150 mesh or less before use. If it is larger than 200 mesh, it may not be able to melt sufficiently, so it is preferable to knead the dicyandiamide finely pulverized with the epoxy resin or the silicone modified resin in advance with a three-roll roll or the like before use.

The component (C) is a curing reaction accelerator, and specifically, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-phenyl-4,5-. Preference is given to using imidazole derivatives such as dihydroxymethylimidazole.

Further, the component (D) used in the liquid epoxy resin composition of the present invention is the alkenyl group of the alkenyl group-containing epoxy resin or the alkenyl group-containing phenol resin and one molecule represented by the following average composition formula (2). A copolymer (silicone-modified resin) obtained by an addition reaction with an SiH group of an organohydrogenpolysiloxane having 20 to 400 silicon atoms and 1 to 5 SiH groups.
It is. H _a R ¹ _b SiO _{{4- (a + b)} / 2} (2) (wherein R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0.002 ≦ a ≦ 0.1, 1.8 ≦ b ≦
It is a number that satisfies 2.2, 1.8 <a + b ≦ 2.3. )

The component (D) is added for the purpose of improving the stress characteristics of the composition. In this case, a method for producing a silicone-modified resin having these structures is already known (Japanese Patent Publication Nos. 63-60069 and 63-60070), and the structure of the epoxy resin part and the structure of the silicone part are appropriately matched to each other. By recombining with each other, it is possible to obtain a composition having good stress characteristics and an optimum structure.

As the alkenyl group-containing phenol resin or alkenyl group-containing epoxy resin, those represented by the following formulas are particularly preferable.

[0024]

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[0025]

Embedded image (P and q are usually 1 ≦ p ≦ 20, preferably 1 ≦ p ≦ 1
0, 1 ≦ q ≦ 5, preferably 1 ≦ q ≦ 3. )

On the other hand, in the organohydrogenpolysiloxane of the above formula (2), R ¹ usually has 1 carbon atom.
To 12, particularly 1 to 10, preferably a substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated bond, for example, a methyl group, an ethyl group, a propyl group, a butyl group, 2
-Alkyl groups such as ethylbutyl group and octyl group, alkenyl groups such as vinyl group, allyl group and hexenyl group, cycloalkyl groups such as cyclohexyl group and cyclopentyl group, aryl groups such as phenyl group and tolyl group, benzyl group, phenylethyl Aralkyl groups such as groups, some or all of the hydrogen atoms bonded to the carbon atoms of these groups are substituted with halogen atoms or cyano groups, for example, chloromethyl group, bromoethyl group, trifluoropropyl group, cyanoethyl group, etc. Is mentioned. Further, a and b are 0.002 ≦ a ≦ 0.1, 1.8 ≦ b ≦ 2.2, and 1.
8 <a + b ≦ 2.3, preferably 0.01 ≦ a ≦ 0.0
5, 1.8 ≦ b ≦ 2.0, 1.81 ≦ a + b ≦ 2.1.

The number of silicon atoms in one molecule of the organohydrogenpolysiloxane is 20 to 400,
It is particularly preferably 40 to 200, and particularly preferably 80 to 150. If it is less than 20, this silicone-modified resin will dissolve in the epoxy resin, and it will not be possible to obtain a fine sea-island structure using the epoxy resin as a matrix, and as a result, sufficient impact resistance cannot be obtained and low stress will be lacking. If it exceeds 400, the silicone-modified resin is phase-separated from the epoxy resin, and the strength of the cured product is weakened, and the composition obtained is thixotropic, requiring fluidity. In some cases it can be a problem. The organohydrogenpolysiloxane is preferably basically linear, but may partially contain a branched structure.

Here, typical examples of the copolymer (silicone-modified resin) used in the present invention include those represented by the following structural formulas (3) to (7).

[0029]

[Chemical 6]

[0030]

[Chemical 7]

In the above formulas, n, m, r and s are each n = 1 to 10, preferably 2 to 5, m = 1 to 3, preferably 1, r = 20 to 200, preferably 30 to 10.
0, s = 0 to 50, preferably a number in the range of 1 to 20, and R is a hydrogen atom or a methyl group.

The epoxy resin composition of the present invention contains the above components (A) to (D). Here, the amount of the dicyandiamide used as the component (B) is the total amount of the epoxy resin containing the component (A). And the total amount of component (D) copolymer 100
It is 2 to 20 parts by weight, especially 4 to 15 parts by weight, relative to parts by weight. If the amount is less than 2 parts by weight, the curability is poor and a cured product having sufficient strength cannot be obtained. If the amount is more than 20 parts by weight,
Not only does the curing speed become too fast and the workability deteriorates,
Good gas cannot be obtained due to the gas generated during curing.

The amount of the curing accelerator as the component (C) is
The total amount of the epoxy resin including the component (A) and the total amount of the component (B) is 0.01 to 10 parts by weight, and particularly 0.5 to 5 parts by weight. If the amount is less than 0.01 parts by weight, the curability is lowered, and if the amount is more than 10 parts by weight, the curability is excellent but the storage stability tends to be lowered.

Further, the compounding amount of the component (D) is the total amount of the epoxy resin containing the component (A), the component (B) and the component (D).
When the total amount of the components is 100 parts by weight, the amount of the organopolysiloxane contained in the copolymer of the component (D) is 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, particularly 2 to 10 parts by weight. Parts by weight. If it is less than 0.5 parts by weight, the cured product will not have impact resistance, and if it is more than 20 parts by weight, the cured product will be inferior in strength.

An inorganic filler is preferably added to the composition of the present invention. The inorganic filler is appropriately selected depending on the application of the epoxy resin composition, and is, for example, crystalline silica, fused silica, ultrafine silica represented by Aerosil, alumina, silicon nitride, aluminum nitride, boron nitride. Typical examples are non-conductive powders such as magnesia and calcium silicate, and conductive powders such as gold powder, silver powder, aluminum powder, copper powder and nickel powder.

The shape of the powder of the above-mentioned inorganic filler is not particularly limited, but any of crushed angular particles, spherical particles, scaly particles and the like can be used depending on the application. Moreover, you may mix and use each. Regarding the particle size distribution of these inorganic fillers, the maximum particle size is 100 microns or less, particularly 50 microns or less, and the average particle size is 5 to 5.
It is preferably 30 microns, especially 5 to 20 microns. When the maximum particle size is larger than 100 microns, it is difficult to fill the minute voids, and when using a dispenser, there is a possibility that the tip of a fine needle may be blocked. If the average particle size is smaller than 5 microns, the particle size becomes too fine and the viscosity tends to increase. On the other hand, if it is larger than 30 microns, the amount of fine powder decreases and the viscosity increases. Therefore, powder having an average particle size of 5 to 30 μm is suitable as a powder having a wide particle size distribution and easy to be most closely packed.

These inorganic fillers are required to have a chlorine ion of 10 ppm or less and a sodium ion of 10 ppm or less as impurities to be extracted under the extraction conditions of 5 g sample / 50 g water at 120 ° C. and 2.1 atm. If the amount of chlorinated ions and sodium ions is more than 10 ppm, the moisture resistance of the semiconductor device encapsulated with the composition of the present invention containing them is deteriorated.

The amount of the inorganic filler compounded is 0 to 95% by weight, preferably 60 to 90% by weight, more preferably 70 to 90% by weight, based on the entire composition. In the present invention, the inorganic filler is used. Even if the agent is highly filled, the viscosity is low.

For the purpose of decreasing the viscosity, the composition of the present invention contains n-butyl glycidyl ether, phenyl glycidyl ether, styrene oxide, t-butyl phenyl glycidyl ether, dicyclopentadiene diepoxide, 1 Diluents such as 4,4-diglycidoxybutane and 1,6-diglycidoxyhexane can be added. Also, if necessary,
Various additives can be blended depending on the application. For example, a silane coupling agent, a titanium-based coupling agent, a coupling agent such as an aluminum-based coupling agent, a coloring agent such as carbon black, a nonionic surfactant, a fluorine-based surfactant, a wetting improver such as silicone oil, or the like. An antifoaming agent or the like can be added depending on the case. Further, in addition to the above-mentioned copolymer (silicone-modified resin), the epoxy resin composition of the present invention contains powders of conventionally known silicone rubbers and gels, thermoplastic resins of methyl methacrylate-butadiene-styrene, etc. You may add as a stress reducing agent.

The method for producing the epoxy resin composition of the present invention is not particularly limited, and known production methods can be adopted. For example, an epoxy resin, a silicone-modified resin and a curing agent are mixed simultaneously or separately. , Stirring, dissolving, mixing and dispersing while adding heat treatment if necessary. next,
The desired liquid epoxy resin composition can be obtained by adding an inorganic filler to this mixture, mixing, stirring, and dispersing. At this time, the mixing, stirring, dispersing, and other devices are not particularly limited, and a reiki machine equipped with a stirring and heating device, a three-roll mill, a ball mill, a planetary mixer, or the like can be used. May be used.

The viscosity of the liquid epoxy resin composition of the present invention is 10,000 poise or less at room temperature (25 ° C.), usually 50 to 5000 poise, preferably 100 to 1000 poise.
Poise is desirable, especially about 100-500 poise, and if the viscosity of the composition is too high, fluidity and workability may deteriorate, and molding defects may occur.

Since the liquid epoxy resin composition of the present invention gives a cured product having a low viscosity and excellent stress characteristics, IC, L
It can be effectively used for manufacturing semiconductor devices such as SI, transistors, thyristors, diodes, etc., and for manufacturing printed circuit boards. Specifically, flip chip sealing, tape automated bonding (TAB), chip on board It is particularly effective for semiconductor encapsulation such as (COB), hybrid IC spot encapsulation, exterior encapsulation, liquid crystal adhesives, ceramic package adhesives, and other exterior materials, adhesives, and seals in various industrial fields. It can also be suitably used as an agent.

When the semiconductor device is sealed,
It can be carried out by adopting conventionally used molding methods such as transfer molding, injection molding, and casting method. In this case, the molding temperature of the epoxy resin composition is preferably 150 to 180 ° C. for 1 to 5 hours.

[0044]

The liquid epoxy resin composition of the present invention is excellent in workability due to its low viscosity and excellent in adhesiveness, has a high glass transition temperature and is free from cracks while maintaining a good state of stress characteristics. Since it is rarely generated, it is suitable as an adhesive for semiconductor elements, a sealing material for semiconductor elements, and the like.

[0045]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Examples and Comparative Examples] Silicone-modified resins (1) to (4) comprising the components shown in Table 1 below are used in JP-B-63.
It was produced according to the production method described in JP-A-60069. The epoxy equivalent and the hydroxyl equivalent of the obtained silicone modified resin are also shown in Table 1.

[0047]

[Table 1]

The structural formulas of the epoxy resins A and B, the phenol resin A, and the organohydrogenpolysiloxanes A and B in Table 1 are as shown below.

[0049]

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Next, the epoxy resin and the above silicone-modified resin were blended in a planetary mixer in the blending ratio shown in Table 2, the silicone-modified resin was completely dissolved while heating, and the remaining components were charged. Stir at room temperature for 10 minutes. Then, the mixture was heated to 50 ° C. and mixed under reduced pressure for 10 minutes to obtain 8 kinds of liquid epoxy resin compositions.

The resulting epoxy resin composition was measured for viscosity, glass transition temperature / expansion coefficient, mechanical strength (flexural strength, flexural modulus), adhesive strength and crack resistance by the following methods. The results are also shown in Table 2. Viscosity A viscometer of a cone plate was used to measure the rotation speed at 25 ° C. Pour into a mold with a glass transition temperature and expansion coefficient of 4 × 4 × 15 mm, defoam and then heat cure at 120 ° C. for 1 hour and 175 ° C. for 2 hours. Minute 5
It was measured by raising the temperature at ° C. The expansion coefficient is a value below the glass transition temperature. Mechanical strength (flexural strength, flexural modulus) After pouring resin into a mold of size 10 × 100 × 4 mm and defoaming, 120 ° C. for 1 hour, then 175 ° C. for 2 hours.
JIS-K-
According to 6911, flexural strength and flexural modulus were measured. Adhesion 10 x 10 x 0.1 mm on an alumina substrate with a width of 10 mm
After screen printing each composition in the size of
Put another alumina substrate on top of it and add a weight of 10g.
It was cured at 20 ° C. for 1 hour and further at 175 ° C. for 2 hours. The shear adhesive strength was measured using this test piece. Crack resistance 15x15x0.1mm on 20mm wide alumina substrate
After screen printing each composition in the size of
A silicon chip cut into 15 × 15 × 0.1 mm was placed on top of it, and a weight of 20 g was applied to it at 120 ° C. for 1 hour.
A test piece for crack resistance measurement was prepared by curing for 2 hours at 175 ° C.

Using this test piece, a temperature cycle of -55 ° C. and 150 ° C. was performed, and the peeling of chips and alumina and the occurrence of cracks were measured every 50 cycles. In addition,
Five test pieces were prepared for each composition.

[0053]

[Table 2] * 2 Dicyandiamide: DYCY (manufactured by Nippon Carbide Industry Co., Ltd.) * 3 Bisphenol A type epoxy resin: RE310
(Nippon Kayaku Co., Ltd.) * 4 SE15: Fused silica having an average particle size of 15 μm (manufactured by Tokuyama Soda Co., Ltd.) * 5 Silver (spherical): Average particle size of 10 μm (Fukuda Metal Co., Ltd.) * 6 Spherical alumina: Average particle diameter 20 μm (manufactured by Showa Denko KK) * 7 KBM403: γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) * 8 2PHZ: 2-phenyl-4,5-dihydroxymethylimidazole ( Shikoku Kasei Co., Ltd.)

Front Page Continuation (72) Inventor Yukiko Wakao 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Gunma Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (3)

[Claims] 1. An epoxy resin represented by the following structural formula (1): (B) dicyandiamide, (C) a curing accelerator, (D) an alkenyl group-containing epoxy resin or alkenyl group alkenyl group containing phenolic resin and the following average compositional formula ^{_{(2) H a R 1 b}} SiO {4- (a + b _{)} / 2} (2) (wherein R ¹ represents a substituted or unsubstituted monovalent hydrocarbon group, and a and b are 0.002 ≦ a ≦ 0.1 and 1.8 ≦ b ≦
It is a number that satisfies 2.2, 1.8 <a + b ≦ 2.3. ), The number of silicon atoms in one molecule is 20 to 40
A liquid epoxy resin composition comprising a copolymer obtained by an addition reaction with 0 and an SiH group of an organohydrogenpolysiloxane having 1 to 5 SiH groups. 2. The content of the component (D) is the above (A),
The liquid epoxy resin composition according to claim 1, wherein the amount of the organopolysiloxane in the copolymer is 0.5 to 20 parts by weight based on 100 parts by weight of the total amount of the components (B), (C) and (D). Stuff. 3. The method according to claim 1, wherein an inorganic filler is blended.
The liquid epoxy resin composition described in 1.