JPH09143251A - Epoxy resin molding material for sealing electronic parts and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin molding material for sealing electronic parts, containing, as essential components, an epoxy resin, a phenolic hydroxyl group-bearing compounds and a specific copolymer as a mold releasing agent, excellent in adhesion to IC chips and lead frames and in mold-releasing properties. SOLUTION: This resin molding material contains, as essential components, (A) an epoxy resin bearing 2 or more epoxy groups, (B) a compound bearing 2 or more phenolic hydroxyl groups, (C) a copolymer of (i) a polyolefin bearing functional groups reactive with phenolic hydroxyl groups (preferably a hydrogenated 1,2-polybutadiene bearing epoxy groups on both chain terminals) with (ii) a polymer containing a hydroxyphenylene group as its structural unit such as a phenol novolak resin. The component A preferably contains >=60wt.% of an alkyl-substituted or unsubstituted biphenyl skeleton such as 4,4'-bis(2,3- epoxypropoxy)biphenyl. The component B is, for example, a poly-p-vinylphenol resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin molding material for encapsulating electronic parts, which has good adhesiveness to insert parts and excellent releasability. The present invention relates to an epoxy resin molding material for encapsulating electronic components such as.

[0002]

2. Description of the Related Art Conventionally, epoxy resin molding materials have been widely used as encapsulating materials in the field of encapsulating electronic parts such as coils, capacitors, transistors and ICs. The reason for this is that the epoxy resin is well balanced in various characteristics such as electrical characteristics, heat resistance, mechanical strength, and adhesiveness with insert parts. Further, a releasing agent is added to these epoxy resin molding materials for encapsulating electronic parts in order to obtain good mold releasability from the mold during molding. Higher fatty acids, higher fatty acid esters, polyolefins, and the like are used as the release agents that have been conventionally used. As the former, natural waxes such as carnauba wax, higher fatty acids such as stearic acid and montanic acid, and esterified products thereof are used. As the latter, low molecular weight substances such as polyethylene and polypropylene and partial oxides thereof are used.

[0003]

In recent years, surface mount type ICs have become the mainstream of IC packages, and TSOP (ThinS
The number of small and thin packages represented by the mall OUTLET PACKAGE) is increasing. These packages have a small sealing resin thickness on the IC chip, and in order to ensure reliability, the epoxy resin molding material for sealing the electronic parts is required to have high adhesiveness. However, if the adhesiveness is increased, naturally the mold release during molding tends to deteriorate. This tendency is remarkable in the new base resin material for improving the adhesiveness. That is, there are many problems relating to mold releasability in materials such as biphenyl-based and dicyclopentadiene-based materials, which are becoming mainstream in recent years, as compared with the conventional base resin-based orthocresol novolac-type epoxy resin-based materials. In order to solve these problems, the present invention provides an epoxy resin molding material for electronic component encapsulation, which has good adhesiveness to an IC chip and a lead frame and excellent mold releasability.

[0004]

The epoxy resin molding material for encapsulating electronic parts of the present invention is (A) an epoxy resin having two or more epoxy groups in one molecule, and (B) 2 in one molecule.
A compound having one or more phenolic hydroxyl groups and (C)
It is characterized in that a copolymer of a polyolefin (C-1) having a functional group capable of reacting with a phenolic hydroxyl group and a polymer (C-2) having a hydroxyphenylene group as a structural unit is an essential component. .

[0005]

DETAILED DESCRIPTION OF THE INVENTION (A) used in the present invention
The epoxy resin having two or more epoxy groups in one molecule of the component is not particularly limited as long as it is generally used in epoxy resin molding materials for electronic component encapsulation, phenol novolac type epoxy resin, orthocresol. Epoxidized novolac resin of phenols and aldehydes including novolac type epoxy resin,
Bisphenol A, bisphenol F, bisphenol S, diglycidyl ether such as alkyl-substituted or unsubstituted biphenol, diaminodiphenylmethane, glycidylamine-type epoxy resin obtained by reaction of polyamines such as isocyanuric acid with epichlorohydrin, olefinic bond such as peracetic acid There are linear aliphatic epoxy resins obtained by oxidation with peracid, epoxy resins having a saturated aliphatic ring (alicyclic epoxy resins), and the like. Further, halogenated epoxy resins obtained by halogenating these epoxy resins such as brominated epoxy resins, for example, diglycidyl ether of brominated bisphenol A, brominated phenol novolac type epoxy resins, etc. are also used for improving flame retardancy. . Specifically, a brominated bisphenol A type epoxy resin is preferably used, and the blending amount thereof is preferably 5 to 40% by weight, more preferably 10 to 30% by weight based on the whole epoxy resin.

Among the epoxy resins as the component (A), which have particularly excellent adhesiveness, there are alkyl-substituted or unsubstituted biphenyl skeleton type epoxy resins, which impart particularly excellent adhesiveness to the epoxy resin molding material of the present invention. In order to achieve this, it is desirable to use 20% by weight or more, preferably 60% by weight or more, based on the total amount of the epoxy resin used. The alkyl-substituted biphenyl skeleton type epoxy resin is one in which the biphenyl ring is substituted with an alkyl group, and the alkyl group is preferably one having 1 to 4 carbon atoms such as a methyl group.
Specific examples of such an epoxy resin include, for example,
Epoxidation of alkyl-substituted or unsubstituted 4,4'-dihydroxybiphenyl such as 4,4'-bishydroxybiphenyl and 4,4'-dihydroxy-3,3 ', 5,5'-tetraalkylbiphenyl using epichlorohydrin That is, an alkyl-substituted or unsubstituted 4,
4'-bis (2,3-epoxypropoxy) biphenyl and the like can be mentioned.

The epoxy resin as the component (A) can be used in combination with any number of kinds as appropriate, but the purity, especially the amount of hydrolyzable chlorine, is preferably small because it is related to the corrosion of aluminum wiring on the element such as IC, and the moisture resistance is high. In order to obtain an excellent epoxy resin molding material for electronic component encapsulation, it is preferably 500 ppm or less. Here, the amount of hydrolyzable chlorine means that 1 g of epoxy resin as a sample is dissolved in 30 ml of dioxane to prepare 1N-K
The value obtained by potentiometric titration after adding 5 ml of OH-methanol solution and refluxing for 30 minutes is used as a scale.

[0008] One of the components (B) used in the present invention
Examples of compounds having two or more phenolic hydroxyl groups in the molecule include phenols such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A and bisphenol F, or naphthols such as α-naphthol, β-naphthol and dihydroxynaphthalene. Resin obtained by condensation or co-condensation of aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde, etc. under acidic catalyst, polyparavinylphenol resin, xylylene group synthesized from phenols and dimethoxyparaxylene There are phenol / aralkyl resins having the above, compounds having a saturated aliphatic ring in the molecule, and the like, and these may be used alone or in combination of two or more kinds. Further, halogenated phenols such as brominated bisphenol A may be used in combination for the purpose of imparting flame retardancy, and the blending amount thereof in the total amount of the component (B) is
5-40% by weight, preferably 10-30% by weight is suitable.

Among the epoxy resin of the component (A) and the compound having a phenolic hydroxyl group of the component (B) in the present invention, those having excellent adhesiveness have a specific saturated aliphatic ring in the structure of the resin or the compound. There are things. Examples of this include a resin in which phenols are added to a terpene compound such as dicyclopentadiene or limonene using an acid catalyst or the like, or a resin obtained by epoxidizing this. As the addition amount of these resins or compounds, the weight of the saturated aliphatic ring is preferably 20% to 40% with respect to the total weight of the component (A) + the component (B).
If it is less than 20% by weight, the effect of high adhesiveness may be insufficient as compared with the conventional orthocresol novolac type epoxy resin / phenol novolac resin type epoxy resin molding material. Further, the epoxy resin having these structures or the compound having a phenolic hydroxyl group can exhibit more excellent adhesiveness when used in combination with the above-mentioned biphenyl skeleton type epoxy resin.

The compounding ratio of the epoxy resin as the component (A) in the epoxy resin molding material is usually 5 to 30% by weight, preferably 7 to 20% by weight, and the compounding ratio of the compound having a phenolic hydroxyl group as the component (B). Is usually 3 to 30% by weight, preferably 5 to 15% by weight.

Further, the epoxy group in the epoxy resin of the component (A), the phenolic hydroxyl group in the compound having the phenolic hydroxyl group of the component (B) and the phenolic hydroxyl group present in the copolymer of the component (C). The equivalent ratio (the number of phenolic hydroxyl groups in the components (B) and (C) / the number of epoxy groups in the component (A)) is not particularly limited, but it is 0.7 to 1. It is preferable to set it in the range of 3.

The epoxy resin molding material for encapsulating electronic parts of the present invention may contain a curing accelerator which accelerates the curing reaction between the epoxy resin and the compound having a phenolic hydroxyl group. Examples of the curing accelerator include triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol, 1,6-diazabicyclo (4,3,0) undecene-5,1, Tertiary amines such as 8-diazabicyclo (5,4,0) undecene-7,
2-methylimidazole, 2-phenylimidazole,
Imidazoles such as 2-phenyl-4-methylimidazole and 2-heptadecylimidazole, organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine, tetraphenylphosphonium tetraphenylborate, triphenyl There are tetraphenylboron salts such as phosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate, and these may be used alone or in combination of two or more. A preferable mixing ratio of the total amount of the curing accelerator is 0.3 to 20 parts by weight, and more preferably 0.6 to 10 parts by weight with respect to 100 parts by weight of the epoxy resin as the component (A).

The component (C) of the present invention, that is, a polyolefin having a functional group that reacts with a phenolic hydroxyl group (C
The copolymer of -1) and the polymer (C-2) having a hydroxyphenylene group as a structural unit has an excellent release property without impairing the adhesiveness of the epoxy resin molding material for electronic component encapsulation of the present invention. It is a component for expressing type. Conventional higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, paraffin wax, polyolefin waxes and the like can improve the releasability by increasing the addition amount, but the adhesiveness may also decrease, and both are compatible. Have difficulty. Therefore, the present inventors synthesized various conventional release agent component-base resin copolymers, and as a result of diligent studies on the relationship between adhesiveness and releasability, the above-mentioned copolymers should be used. It was found that it is possible to achieve both releasability and adhesiveness. Examples of the polyolefin part of the polyolefin (C-1) having a functional group that reacts with a phenolic hydroxyl group include polyethylene, polypropylene, 1,2.
-Polybutadiene, 1,4-polybutadiene, and even those obtained by hydrogenating unsaturated double bonds of these polybutadienes may be mentioned. As the polyolefin having a functional group that reacts with a phenolic hydroxyl group, one having a functional group such as an epoxy group or a carboxyl group at the terminal or in the molecule of the polyolefin main chain is used.

Polyolefin having the above functional group (C-
Preferred examples of 1) include hydrogenated 1,2-polybutadiene having epoxy groups at both ends, hydrogenated 1,2-polybutadiene having carboxyl groups at both ends, and polyethylene having epoxy groups at both ends. it can.
By having a functional group, these polyolefins can easily form a copolymer such as a block copolymer or a graft copolymer with the polymer (C-2) having a hydroxyphenylene group such as a phenol resin. That is, when it has an epoxy group, the copolymer of the component (C) can be obtained by carrying out an addition reaction in the presence of a curing accelerator that promotes the reaction between the epoxy group and the phenolic hydroxyl group.
Further, when it has a carboxyl group, a copolymer of the component (C) can be obtained by a condensation reaction by using an acid catalyst. In any case, when a phenol resin is used as the polymer (C-2), in order to avoid gelation, the phenolic hydroxyl group of the phenol resin is 3 to 20 per equivalent of the functional group of the polyolefin (C-1). It is desirable to carry out the reaction at a ratio of double equivalent, preferably 5 to 10 equivalent.

Specific examples of the polymer (C-1) used for producing the copolymer of the component (C) include, for example,

[0016]

Embedded image Partial oxides of low molecular weight polyethylene and the like can be mentioned.

The molecular weight of the polyolefin (C-1) used for producing the above-mentioned copolymer (component (C)) is not particularly limited, but it is a weight average molecular weight of 500-500.
The range of 5000 is preferable, and more preferably 1000 to 3000.
Is preferable. The reason for this is that if the molecular weight is smaller than this range, there is no effect on releasability, and if it is large, the softening point of the copolymer of component (C) becomes high, and the dispersion in the molding material becomes poor, so that it becomes difficult to separate. This is because the effect on moldability may be reduced.

In the epoxy resin molding material for encapsulating electronic parts of the present invention, higher fatty acids, higher fatty acid metal salts, ester waxes, polyethylene waxes and the like which are generally used as a release agent other than the component (C). Any number of types can be used at the same time. The compounding ratio of the releasing agent other than the component (C) is usually the epoxy resin 100 of the component (A).
0.1-3 parts by weight, preferably 0.5-
1.5 parts by weight is suitable.

Further, the epoxy resin molding material for encapsulating electronic parts of the present invention contains, as an inorganic filler, fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, boron nitride, beryllia, zirconia. It is possible to blend one or more kinds of powders such as, or spherical particles of these, single crystal fibers such as potassium titanate, silicon carbide, silicon nitride and alumina, and glass fibers. The content of the inorganic filler is 50 to 95% by weight, preferably 70 to 95% by weight based on the whole epoxy resin molding material from the viewpoint of hygroscopicity, reduction of linear expansion coefficient and improvement of strength.
90% by weight is suitable. Among the above-mentioned inorganic fillers, fused silica is, from the viewpoint of reducing the linear expansion coefficient,
Alumina is preferable from the viewpoint of high thermal conductivity, and the shape of the filler is preferably spherical from the viewpoints of fluidity at the time of molding and mold abrasion.

The epoxy resin molding material for encapsulating electronic parts of the present invention includes carbon black, colorants such as organic dyes, epoxysilane, aminosilane, alkylsilane,
Coupling agents such as vinyl silanes, organic titanates, aluminum alcoholates and the like can be used. The mixing ratio of the coupling agent is preferably 1 to 15 parts by weight, more preferably 2 to 8 parts by weight, based on 100 parts by weight of the epoxy resin as the component (A).

Further, in the epoxy resin molding material for encapsulating electronic parts of the present invention, flame retardants such as antimony trioxide, antimony pentoxide and aluminum hydroxide can be used as flame retardants other than the above halides. it can. The preferred blending ratio of these flame retardants is 1 to 30 parts by weight, more preferably 2 to 15 parts by weight, relative to 100 parts by weight of the epoxy resin as the component (A).

As a general method for producing a molding material using the above raw materials, a predetermined amount of the raw material mixture is thoroughly mixed by a mixer or the like, and then a heat roll,
A molding material can be obtained by kneading with an extruder or the like, cooling and pulverizing.

As a method for sealing electronic parts by using the molding material obtained in the present invention, the low-pressure transfer molding method is the most general method, but injection molding, compression molding, casting or the like is also possible. is there.

[0024]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples of the present invention and Comparative Examples thereof, but the present invention is not limited to these Examples.

Examples 1 to 11 and Comparative Examples 1 to 13 In producing the molding materials of Examples and Comparative Examples shown in Tables 2 and 3, various epoxy resins and curing agents as the component (A) and the component (B) were used. The following was used as

[0026]

Embedded image * 1: o-cresol novolac type epoxy resin (epoxy equivalent = 200), Sumitomo Chemical Co., Ltd., ESCN
-195

[0027]

Embedded image * 2: Tetramethylbiphenyl type diepoxy resin (epoxy equivalent = 188), manufactured by Yuka Shell Epoxy Co., Ltd.
YX-4000H

[0028]

Embedded image

[0029]

Embedded image As the copolymer of the component (C), those shown in Table 1 were used.

[0030]

[Table 1] The above-mentioned epoxy resin, curing agent, copolymer shown in Table 1,
Epoxy equivalent 375, softening point 80 ° C, bromine content 48 weight% brominated bisphenol A type epoxy resin, 1,8-
Diazabicyclo (5,4,0) undecene-7, carnauba wax, non-oxidized polyethylene wax having a weight average molecular weight of 3000, antimony trioxide, carbon black,
Using γ-glycidoxypropyltrimethoxysilane as a coupling agent and quartz glass powder as raw materials, Table 2 and Table 3
Compounding was carried out in the weight ratio shown in Table 1, and roll kneading was carried out under the conditions of a kneading temperature of 80 to 90 ° C. and a kneading time of 10 minutes to prepare molding materials of Examples and Comparative Examples. In Tables 2 and 3, the amounts of the components are shown in parts by weight. Tables 4 and 5 show the characteristics of the molding materials of Examples and Comparative Examples, and Table 6 shows the details of the characteristic evaluation method.
As shown in Tables 4 and 5, Examples 1 to 11 have excellent performance in which the releasability and the marking property are compatible with each other as compared with the comparative example. Furthermore, since Examples 1 to 11 exhibit excellent releasability, and have a high ability to maintain the original adhesiveness of the base resin, they also have excellent reflow crack resistance, which is the most important characteristic of surface mount ICs. I know that

[0031]

[Table 2] * 7: 1,8-diazabicyclo (5,4,0) undecene-7 * 8: γ-glycidoxypropyltrimethoxysilane * 9: non-oxidizing polyethylene wax (molecular weight 300
0)

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

[0035]

[Table 6]

[0036]

The epoxy resin molding material obtained according to the present invention can be greatly improved in crack resistance as compared with the conventional one. In the field of electronic parts, especially in ICs such as FP (flat package) and SOP (small outline package), the package is thin and small, and in combination with the increase in size of the device, package crack resistance is strongly required. It can be widely applied to these products and has great industrial value.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a method of measuring releasability.

[Explanation of symbols]

 1 mold 2 molded product

Claims (8)

[Claims] 1. A reaction with (A) an epoxy resin having two or more epoxy groups in one molecule, (B) a compound having two or more phenolic hydroxyl groups in one molecule, and (C) a phenolic hydroxyl group. Polyolefin having functional group (C
An epoxy resin molding material for electronic component encapsulation, comprising a copolymer of -1) and a polymer (C-2) having a hydroxyphenylene group as a structural unit as an essential component. 2. The epoxy resin molding material for electronic component encapsulation according to claim 1, wherein the polyolefin used for producing the component (C) has a weight average molecular weight of 1,000 to 3,000. 3. A hydrogenated 1,2-polybutadiene having an epoxy group as the polyolefin (C-1) used for producing the component (C), a hydrogenated 1,2-polybutadiene having a carboxyl group, or a polyethylene having an epoxy group. The epoxy resin molding material for encapsulating an electronic component according to claim 1 or 2. 4. A polymer (C-) having a hydroxyphenylene group as a structural unit, which is used for producing the component (C).
2) is a phenol novolac resin, The epoxy resin molding material for electronic component sealing in any one of Claims 1-3. 5. The encapsulating electronic component according to claim 1, wherein the epoxy resin as the component (A) is alkyl-substituted or unsubstituted 4,4′-bis (2,3-epoxypropoxy) biphenyl. Epoxy resin molding material. 6. The electron according to claim 1, wherein the epoxy resin of component (A) or the compound having a phenolic hydroxyl group of component (B) is an epoxy resin or compound having a saturated aliphatic ring in the molecule. Epoxy resin molding material for component encapsulation. 7. The epoxy resin molding material for encapsulating electronic components according to claim 1, further comprising a brominated epoxy resin as the epoxy resin as the component (A). 8. A semiconductor element and a method of encapsulating the same.
7. A semiconductor device comprising an encapsulating resin of the epoxy resin molding material for encapsulating an electronic component according to any one of 7 to 7.