JP3264183B2 - Method for producing epoxy group-containing organopolysiloxane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an epoxy group-containing organopolysiloxane.

[0002]

2. Description of the Related Art Epoxy resins are excellent in heat resistance, moisture resistance, electrical properties, adhesiveness, etc., and various properties can be imparted by formulating them. Therefore, they are used as epoxy resin compositions as paints, adhesives, structural materials, and electrical insulating materials. Widely used for industrial materials such as. For example, an epoxy resin composition is generally used as a sealing material for electronic circuit components such as semiconductor devices.

In recent years, it has become very important to mount a semiconductor device on a wiring board at high density in order to reduce the size of electronic equipment. Therefore, instead of the conventional "insertion mounting method" in which the lead pins of the semiconductor device are inserted into the holes of the substrate and soldered from the back side of the substrate, the semiconductor device is temporarily fixed to the surface of the substrate and then the whole is heated and soldered. `` Surface mount method ''
Has become commonplace. In the conventional insertion mounting method, only the lead pins are heated. However, in this surface mounting method, the entire semiconductor device is heated (200 to
260 ° C.), for example, in the case of an IC package, the moisture absorbed by the encapsulant explosively evaporates and expands during storage, causing peeling between the silicon chip, the lead frame, the die pad and the encapsulant. In addition, there has been a problem that cracks are generated in the sealing material and the moisture resistance reliability is reduced.

To solve this problem, an epoxy resin having excellent adhesiveness, an epoxy resin composition containing a curing agent (Japanese Patent Application Laid-Open No. 4-173828), a semiconductor sealant having a high filler content and low water absorption. Resin composition for stopping
Many proposals have been made to improve the adhesiveness of a sealing material to a silicon chip or a lead frame or to reduce the water absorption of the sealing material to solve the above problem. However, in these methods, the releasability from the mold at the time of encapsulation molding is significantly reduced due to the high adhesiveness and the small curing shrinkage.
There is a problem that the essential properties of the molding material are impaired, such as damage to the package.

[0005]

The present inventors have conducted intensive studies to solve these problems, and as a result, have found a method for producing an epoxy group-containing organopolysiloxane suitable for blending an epoxy resin composition. When the epoxy group-containing organopolysiloxane obtained by this method is used for encapsulating a semiconductor with an epoxy resin composition, the releasability from the mold is greatly improved without impairing the adhesion to the silicon chip or lead frame. Thus, the present invention has been completed.

[0006]

That is, the present invention is a method for producing an epoxy group-containing organopolysiloxane, which comprises reacting a carboxyl group-containing organopolysiloxane and a higher fatty acid with an epoxy compound.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, a method for producing an epoxy group-containing organopolysiloxane obtained by reacting a carboxyl group-containing organopolysiloxane and a higher fatty acid with an epoxy compound will be described.

[0008] The carboxyl group-containing organopolysiloxane in the present invention is an organopolysiloxane having a carboxyl group.

Embedded image (However, R is selected from a methyl group and a phenyl group, not necessarily the same, and X _{1 to} X ₃ are at least one of
One represents an organic group having one carboxyl group, and the rest represents either a methyl group or a phenyl group. Also, m, n
Represents an integer of 0 or more. ) Means a carboxyl-modified silicone oil represented by Preferred specific examples include side-chain type carboxyl-modified polydimethylsiloxane having a carboxyl equivalent of 300 to 5,000, one-terminal carboxyl-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane at both ends, and more preferably both having a carboxyl equivalent of 500 to 3000. Terminal carboxyl-modified polydimethylsiloxane;
More than one species may be used in combination.

The higher fatty acid in the present invention is one per molecule.
It means a hydrocarbon compound having at least one carboxyl group and having an aliphatic chain having 10 or more carbon atoms. Preferred specific examples are capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachiic acid, behenic acid,
Saturated fatty acids such as cerotic acid and melicic acid, unsaturated fatty acids such as palmitoleic acid, oleic acid, elaidic acid, erucic acid, linoleic acid, linoleic acid, eleostearic acid, and succinic acid; fatty acid derivatives such as hydroxystearic acid; Natural waxes such as lanolin wax and montan wax having a valency of 20 or more, and synthetic waxes may be mentioned, and two or more kinds may be used at the same time.

The mixing ratio of the carboxyl group-containing organopolysiloxane and the higher fatty acid is not particularly limited as long as both components are compounded. (Weight of carboxyl group-containing organopolysiloxane) :( weight of higher fatty acid) The range of (weight) = 90: 10 to 50:50 is preferably used from the viewpoint of improving the releasability when used in the epoxy resin composition.

On the other hand, the epoxy compound to be reacted with the carboxyl group-containing organopolysiloxane and the higher fatty acid may be any one having at least one epoxy group in one molecule, and particularly has two epoxy groups in one molecule. Are preferably used. Preferred specific examples thereof include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin,
4'-bis (2,3-epoxypropoxy) biphenyl, 4,4'-bis (2,3-epoxypropoxy)-
3,3 ′, 5,5′-tetramethylbiphenyl, 1,5
Di (2,3-epoxypropoxy) naphthalene, 1,
6-di (2,3-epoxypropoxy) naphthalene,
Examples thereof include 2,7-di (2,3-epoxypropoxy) naphthalene and 9,9′-bis (2,3-epoxypropoxyphenyl) fluorene, and two or more kinds may be used at the same time.

The mixing ratio of the carboxyl component of the carboxyl group-containing organopolysiloxane and the higher fatty acid to the epoxy compound is such that the total amount of the epoxy groups exceeds the total amount of the carboxyl groups so that the epoxy groups remain after the reaction. Although it is good, the compounding ratio in which the epoxy equivalent of the reaction product becomes 400 to 3000 is preferable.
When the mixing ratio of the epoxy compound increases and the epoxy equivalent of the reaction product is smaller than the above range, sufficient releasability cannot be obtained when used in an epoxy resin composition, and the mixing ratio of the epoxy compound decreases to reduce the reaction. When the epoxy equivalent of the product is larger than the above range, when used in an epoxy resin composition for semiconductor encapsulation, the adhesiveness to a silicon chip or a lead frame tends to decrease.

The reaction of a carboxyl group-containing organopolysiloxane and a higher fatty acid with an epoxy compound is 10%.
It can be achieved by reacting at a temperature of 0 to 200 ° C. for 3 to 60 minutes. In the above reaction, not only the components are simultaneously mixed and reacted, but also the carboxyl components may be sequentially reacted with the epoxy component, or the epoxy components may be sequentially reacted with the mixture of the carboxyl components. Tertiary amines and organic phosphine compounds are preferably used as the reaction catalyst, and the amount of the reaction catalyst to be added is preferably 0.1 to 1.0% by weight based on the total amount of the mixture.

The carboxyl group-containing organopolysiloxane of the present invention and the epoxy group-containing organopolysiloxane obtained by reacting a higher fatty acid with an epoxy compound are mixed with various resin compositions to release the resin composition from a mold. It is suitable as a resin additive for improving the properties, molding fluidity, flexibility, and low stress.

In particular, the epoxy group-containing organopolysiloxane obtained by the method of the present invention can be used in an epoxy resin composition containing the epoxy resin (A), the curing agent (B) and the filler (C) as essential components. The mold releasability, molding fluidity, flexibility, and low stress property can be improved.

Next, the epoxy resin composition will be described.

The epoxy resin (A) is not particularly limited as long as it has two or more epoxy groups in one molecule.
For semiconductor encapsulation, cresol novolak epoxy resin, phenol novolak epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, 4,4′-bis (2,3-epoxypropoxy) Biphenyl, 4,4
'-Bis (2,3-epoxypropoxy) -3,3',
5,5'-tetramethylbiphenyl, 1,5-di (2,
3-epoxypropoxy) naphthalene, 1,6-di (2,3-epoxypropoxy) naphthalene, 2,7-
Di (2,3-epoxypropoxy) naphthalene, 9,9
'-Bis (2,3-epoxypropoxyphenyl) fluorene is preferably used, and two or more of them may be used in combination. Among them, 4,4'-bis (2,3
-Epoxypropoxy) biphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'
-Tetramethylbiphenyl, 1,5-di (2,3-epoxypropoxy) naphthalene, 1,6-di (2,3-epoxypropoxy) naphthalene, 2,7-di (2,3-
It is particularly preferable for surface mounting applications to use 70% by weight or more of the total amount of the epoxy resin (A) such as epoxypropoxy) naphthalene and 9,9'-bis (2,3-epoxypropoxyphenyl) fluorene.

In the present invention, the amount of the epoxy resin (A) is usually 2 to 20% by weight, preferably 3 to 20% by weight of the whole composition.
10% by weight. If the amount of the epoxy resin (A) is less than 2% by weight, the moldability tends to be insufficient.

The curing agent (B) in the present invention is not particularly limited as long as it is a substance which is cured by reacting with the epoxy resin (A), but a phenolic compound is preferably used for semiconductor encapsulation. Is phenol novolak resin, cresol novolak resin, formula (II)

Embedded image (However, Ar is selected from phenol, cresol, and naphthol, not necessarily the same, and the hydroxyl group of naphthol may be at any substitution position, and n represents an integer of 0 or more.) Hydroxyaryl aralkyl resins, bisphenol A, bisphenol F, bisphenol AP, bisphenol C, bisphenol E, bisphenol Z, dihydroxybiphenyls, dihydroxynaphthalenes, trishydroxyphenylmethanes, trishydroxyphenylethanes, and trishydroxyphenylpropanes And two or more of them may be used in combination. Among them, the above formula (II)
It is particularly preferable to use 50% by weight or more of the hydroxyarylaralkyl resins represented by in the total amount of the curing agent (B) for surface mounting applications.

In the present invention, the compounding amount of the curing agent (B) is usually 2 to 15% by weight of the whole composition, preferably the composition including the phenolic hydroxyl group of the curing agent (B) and the epoxy resin (A). The ratio of the total number of epoxy groups contained in each component is (phenolic hydroxyl group) / (epoxy group)
= 0.5-2.0, 0.7-1.
An amount in the range of 5 is optimal. Outside the above range, heat resistance, curability and mechanical properties tend to be impaired.

In the present invention, the epoxy resin (A)
A curing catalyst may be used for accelerating the curing reaction between the curing agent and the curing agent (B). The curing catalyst is not particularly limited as long as it promotes the curing reaction. For example, imidazoles, tertiary amines, organic phosphine compounds and the like are used. Among them, 1,8-diazabicyclo (5,4,0) undecene-
7,6-Dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7 and their respective two phenol novolak salts, triphenylphosphine, tetraphenylphosphonium tetraphenylborate salts and the like are preferably used. .

As the filler (C) in the present invention, amorphous silica, crystalline silica, calcium carbonate, magnesium carbonate, alumina, magnesia, clay, talc, calcium silicate, titanium oxide, antimony oxide, asbestos, glass For example, amorphous silica, crystalline silica, and alumina are preferably used for the purpose of lowering the coefficient of linear expansion and increasing the thermal conductivity for semiconductor encapsulation. These can be used together.

The proportion of the filler (C) is not particularly limited, but is 7% of the total composition for semiconductor encapsulation from the viewpoint of linear expansion coefficient.
The content is preferably 0% by weight or more, and more preferably 80% by weight or more from the viewpoint of water absorption in surface mounting applications.

The surface treatment of the filler (C) with a coupling agent in advance is preferable in terms of reliability for semiconductor encapsulation. The type thereof is not particularly limited, and for example, a silane coupling agent, a titanate coupling agent, and an aluminum-based coupling agent can be used. If necessary, two or more types can be used in combination. Especially epoxy group in the molecule,
Silane coupling agents having a primary to tertiary amino group, a mercapto group, and a ureido group are preferably used, and specific examples thereof include γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ- (2
-Aminoethyl) aminopropyltrimethoxysilane,
γ-ureidopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropyldimethoxymethylsilane, γ-mercaptopropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. No.

The epoxy group-containing organopolysiloxane (D) produced in the present invention has a function of greatly improving the releasability from the mold without impairing the adhesiveness of the epoxy resin composition to the substrate. Further, it is also very excellent in terms of burr characteristics and fluidity during molding as a molding material.

When the epoxy group-containing organopolysiloxane (D) produced in the present invention is incorporated into an epoxy resin composition, the reason why such excellent properties are exhibited is not clear, but the releasing effect of the carboxyl-modified silicone oil is not clear. , A lubricant effect of higher fatty acids, an effect of improving compatibility with an epoxy resin composition by reacting them with an epoxy resin,
In particular, by reacting both a carboxyl-modified silicone oil and a higher fatty acid with an epoxy resin, there are a large number of molecules having all of these skeletons in one molecule in the reaction product. We believe that the improvement in uniformity is the reason why remarkable effects are observed on mold release properties, molding burr characteristics, and fluidity. In addition, by appropriately leaving epoxy groups in the epoxy group-containing organopolysiloxane (D), when used as a semiconductor encapsulating material, for example, a reaction product during the post-curing after molding may react with a silicon chip or a lead frame. It is considered that they are taken into the epoxy resin matrix from the interface by reaction and do not impair the adhesiveness.

The compounding amount of the epoxy group-containing organopolysiloxane (D) obtained by the production method of the present invention is preferably 0.1 to 2.0% by weight of the whole epoxy resin composition. If the content is less than 0.1% by weight, the effect is small, and if it is more than 2.0% by weight, the adhesion to the substrate and the burr characteristics tend to decrease.

The epoxy resin composition is prepared by mixing the above components with a blender or a mixer.
It is manufactured by heating and melting and kneading using a known kneading method such as a single screw or twin screw extruder and a co-kneader.

[0029]

The present invention will be described below in detail with reference to examples. Parts and% in Examples are parts by weight and% by weight unless otherwise specified.

Examples 1 to 5 and Comparative Examples 1 and 2 (Production and Analysis of Epoxy Group-Containing Organopolysiloxane) The raw materials shown in Table 1 are shown in Table 2 in a 1-liter three-necked flask equipped with a stirrer and a thermometer. After heating to 140 ° C., 1 part of triphenylphosphine was added while stirring the mixture and reacted for 1 hour to obtain an epoxy group-containing organopolysiloxane. Table 2 also shows the measurement results of the epoxy equivalent and the melt viscosity at 100 ° C. (measured with a B-type viscometer) of the obtained epoxy group-containing organopolysiloxane. From the analysis of the FT-IR spectrum, it was found that any of the epoxy group-containing organopolysiloxanes contained 1%.
710~1720cm absorption of the carboxyl group in the vicinity of ^-1 disappeared 1730～1740Cm ^-1 to the absorption of ester groups appears near, it was confirmed that with the absorption of epoxy group in the vicinity of 910～920Cm ^-1. FIG. 1 shows an FT-IR chart of the epoxy group-containing organopolysiloxane produced in Example 1 as a typical example.

[0031]

[Table 1]

[0032]

[Table 2]

Examples 6 to 12 and Comparative Examples 3 to 9 (Production and Evaluation of Epoxy Resin Composition) The blends shown in Table 3 were mixed with the blend compositions shown in Table 4 using a mixer. This was melt-kneaded using a twin-screw extruder having a barrel setting temperature of 90 ° C., and then cooled and pulverized to produce an epoxy resin composition for semiconductor encapsulation.

Using this composition, molding was performed at 175 ° C. × 2 minutes using a low-pressure transfer molding machine.
It was cured for 5 hours. Then, the physical properties of each composition were measured by the following methods.

Releasability: After sufficiently cleaning the mold, the diameter is 1 mm.
The molding of a cylinder having a length of 2 cm and a length of 2 cm was repeated 10 times, and the force required to protrude from the mold immediately after each molding was measured using a push-pull gauge. The average of the measured values is 20
Those with kg or more were represented by x (poor), those with 10 kg or more but less than 20 kg were represented by Δ (poor), those with 5 kg or more but less than 10 kg were represented by （(good), and those with less than 5 kg were represented by 、 ５ (excellent).

Adhesiveness: Eight pieces each of 160-pin QFP devices (package size: 27 × 27 × 3.3 mm, chip size: 9 × 9 × 0.5 mm) are molded, cured, and then heated at 85 ° C./85% RH. For 72 hours, and heat-treated in an IR reflow furnace at a maximum temperature of 245 ° C. The inside of the package after the processing was observed using an ultrasonic flaw detector, and the number of defects was determined as those having peeling on each of the chip surface and the die pad (42 alloy) surface.

Burr characteristics: Molding was performed using a mold for measuring burrs, and the length of the transparent burrs protruding into the gap between the dies was measured.
Those of 5 mm or more were represented by x (poor), those of 2 mm or more and less than 5 mm were represented by Δ (poor), and those of less than 2 mm were represented by ○ (good).

The results of these evaluations are also shown in Table 4.

[0039]

[Table 3]

[0040]

[Table 4]

From Table 4, it can be seen that the epoxy resin compositions (Examples 6 to 12) containing the epoxy group-containing organopolysiloxane obtained by the production method of the present invention as a resin additive have excellent mold release properties. Good adhesion to silicon chips and die pads. Also, the burr characteristics are good.

On the other hand, the compound containing a montanic acid ester wax, which is often used as a mold release agent (Comparative Example 3), and the compound containing a reaction product of a montanic acid wax and an epoxy resin (Comparative Example 5) are used. The moldability is very poor, and the adhesion to silicon chips and die pads is not sufficient. In addition, a compound containing epoxy-modified polydimethylsiloxane (Comparative Example 4) or a compound containing a reaction product of carboxyl-modified polydimethylsiloxane and an epoxy resin (Comparative Example 6) have insufficient release properties, and Adhesion to chips and die pads is also poor. Further, even when a reaction product of a montanic acid wax and an epoxy resin and a reaction product of a carboxyl-modified polydimethylsiloxane and an epoxy resin are used in combination, no remarkable improvement effect is observed.

[0043]

The epoxy group-containing organopolysiloxane obtained by the method of the present invention imparts excellent mold releasability to the molding material and does not reduce the adhesiveness to the base material. It is suitable as an additive for the composition. Further, the epoxy resin composition for semiconductor encapsulation containing the epoxy group-containing organopolysiloxane is suitable as a semiconductor encapsulant for surface mounting applications.

[Brief description of the drawings]

FIG. 1 is an FT-IR chart of the epoxy group-containing organopolysiloxane obtained in Example 1.

Claims (1)

(57) [Claims] 1. A method for producing an epoxy group-containing organopolysiloxane, comprising reacting a carboxyl group-containing organopolysiloxane and a higher fatty acid with an epoxy compound.