JPH0241353A - Resin composition for sealing semiconductor - Google Patents

Abstract

PURPOSE:To obtain the subject resin composition with low stress excellent in thermal shock and solder heat resistance by blending a modified epoxy resin with a bismaleimide compound, phenol-aralkyl resin and/or resol-aralkyl resin and inorganic filler. CONSTITUTION:(A) A modified epoxy resin containing uniformly dispersed silicone polymer with <=1mum particle size prepared by additional reaction of an addition reaction type silicon polymer in the presence of a graft polymer between an epoxy resin and a vinyl polymer or by polymerization of a vinyl- modified silicone with another arbitrary monomer, (B) a bismaleimide of the formula (R is >=2C divalent organic group), (C) a phenol-aralkyl resin and/or resol-aralkyl resin and (D) an inorganic filler are blended as the main components in such a ratio that (B) is 30-80wt.% of the total composition, (C) 10-500 pts.wt. based on 100 pts.wt. (B), (A) 0.1-10 equivalent ratio based on (C) and (D) 100-600 pts.wt. based on 100 pts.wt. composition, thus obtaining the subject resin composition for sealing semiconductors.

Description

[Detailed description of the invention] [Industrial application field] The present invention requires low stress, low coefficient of thermal expansion, and high reliability with excellent thermal shock resistance and soldering heat resistance without impairing heat resistance. The present invention relates to a semiconductor encapsulating resin composition suitable for encapsulating electronic components such as semiconductors.

[Conventional technology]

In recent years, so-called plastic encapsulation using thermosetting resins such as epoxy resins has been widely put into practical use as a method for encapsulating semiconductors, taking advantage of its economic advantages such as low raw material requirements and suitability for mass production. In particular, resin compositions containing polyfunctional epoxy resins, novolac type phenolic resins, and inorganic fillers as main components have become mainstream as sealing resins because they have excellent heat resistance, moldability, and electrical properties.

[Problem to be solved by the invention]

On the other hand, as semiconductor chips have become more highly integrated, their chip sizes have become larger. In addition, the shape of packages has become smaller and smaller, as seen in flat packages, as opposed to larger chips due to higher density mounting on substrates and surface mounting.
There is a trend toward thinner products, and this has led to defects that were not seen with conventional sealing resins. In other words, stress in the resin due to the difference in thermal expansion coefficient between the sealing resin and the chip increases the size of the chip and thins the resin layer, resulting in thermal shock that can cause cracks in the puffy basin film, aluminum wiring slides, or cracks in the sealing resin. Also, as the package itself is exposed to the solder bath temperature due to surface mounting, the moisture inside the package expands rapidly, causing damage such as cracks in the package, reducing the moisture resistance of the semiconductor, and ultimately reducing reliability. It causes a decline in sexual performance. Therefore, it is desired to develop a sealing resin that has less stress and excellent solder heat resistance.

One possible way to reduce stress is to reduce the coefficient of thermal expansion of the resin to reduce the difference between it and that of the chip, but the difference between the coefficient of thermal expansion of the resin and that of the chip is large, so in order to reduce this requires the use of a large amount of inorganic filler with a low coefficient of thermal expansion in the resin, but currently a considerable amount of inorganic filler is already being used, and further increasing this amount may cause deterioration of moldability. Become. On the other hand, attempts have been made to add plasticizers or to use flexible epoxy resins or phenolic resins in order to lower the elastic modulus of the resin and reduce stress, but these methods have not produced results. The cured product had a problem in heat resistance.

In addition, as exemplified by JP-A-58-108220, a method of dispersing rubber particles in a sealing resin to provide crack resistance while maintaining heat resistance has also been invented, but methods such as solder bath etc. There were several problems such as poor impact resistance at high temperatures exceeding the glass transition temperature of the sealing resin.

The present invention is designed for semiconductor encapsulation that has low stress, thermal shock resistance, and excellent solder heat resistance, which is required for semiconductor encapsulation resins that require high reliability such as highly integrated circuits. The purpose is to provide a resin composition.

[Means to solve problems]

As a result of various studies, the present inventor has developed a modified epoxy resin in which silicone polymer fine particles are dispersed in a graft polymer of an epoxy resin and a vinyl polymer, a maleimide resin, and two or more active OH groups that react with the same. As a result of our efforts to provide a resin that undergoes a curing reaction with an aralkyl resin that contains phenyl groups as repeating units, it reduces stress, is effective in thermal shock resistance, and has excellent soldering heat resistance. , arrived at the present invention.

That is, the present invention provides (a) a modified epoxy resin in which a silicone polymer is uniformly dispersed in a graft polymer of an epoxy resin and a vinyl polymer with a particle size of 1.0 μ or less, (b) a bismaleimide compound, (c) This is a resin composition for semiconductor encapsulation characterized by containing as a main component a phenol aralkyl resin and/or a resorcin aralkyl resin, (d>inorganic filler).

As the epoxy resin used in (a) of the present invention, commonly used epoxy resins can be used as long as they are polyhydric epoxy resins, and glycidylated products such as phenol novolak and cresol novolak can be used in view of their heat resistance and electrical properties. Novolak epoxy resin is preferred, but other compounds having two or more active hydrogens in one molecule, such as polyhydric phenols such as bisphenol A, bishydroxydiphenylmethane, resorcinol, bishydroxydiphenyl ether, and tetrabromobisphenol A, Ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, pentaerythritol, diethylene glycol, polypropylene glycol, bisphenol A-ethylene oxide adduct, polyhydric alcohols such as trishydroxyethyl isocyanurate, ethylenediamine, polyamino compounds such as aniline, adipic acid ,
Glycidyl-type epoxy resins obtained by reacting polycarboxylic compounds such as phthalic acid and isophthalic acid with epichlorohydrin or 2-methylepichlorohydrin, aliphatic (alicyclic) resins such as dicyclopentadiene diepoxide, butadiene dimer diepoxide, It is possible to use one or more epoxy resins selected from epoxy resins such as (including).

The graft polymer of an epoxy resin and a vinyl polymer in (a) of the present invention is typically produced by polymerizing a vinyl monomer in the presence of an epoxy resin. The term graft polymer as used herein includes what is commonly referred to as a block polymer, where the vinyl monomers used to make the vinyl polymer include alkenyl aromatics such as styrene, vinyltoluene, etc., methyl methacrylate, dodecyl methacrylate, butoxyethyl methacrylate,
glycidyl methacrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
Acrylic esters such as hydroxyethyl acrylate, trimethylolpropane triacrylate, etc., acrylic compounds without ester groups such as acrylonitrile, acrylic acid, butoxymethylacrylamide, methacrylamide, etc., vinyl acetate, vinyl-7'7
Typical examples include non-conjugated vinyl compounds such as ester, vinyl persatate, vinyl chloride, vinylidene chloride, ethylene, and allyl acetate, and conjugated diene compounds such as butadiene, isoprene, and chloroprene.Other examples include vinyl silicone, dibutyl fumarate, and monomethyl. Polymerizable vinyl compounds such as fluorine compounds of methacrylic acid and acrylic acid such as malate, diethyl itaconate, trifluoroethyl methacrylate, and tetrafluoropropyl methacrylate can also be used. In order to polymerize the above-mentioned t-nyl monomers to form t-nyl polymers, a radical initiator such as lauroyl peroxide, benzoyl peroxide, tert-butyl perbenzoate, dimethyl dibenzoyl peroxyhexane, tert-butyl perpivalate, di-tert-yl peroxide, etc. is usually used. Medium lipyl peroxide, 1.1-bistert-butyl peroxide 3゜3.5-trimethylcyclohexane, dimethyl di-tert-butyl peroxyhexane, tert-butyl cumyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydroper oxide, tert-butyl peroxyallyl carbonate, dioctyl peroxydicarbonate,
Using peroxides such as tert-butyl peroxymaleic acid, succinic peroxide, tert-butyl peroxyisopropyl carbonate, hydrogen peroxide, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile, radical Polymerization is typical.

Further, if necessary, a reducing agent may be used in combination to carry out so-called redox polymerization, and a polymerization inhibitor such as hydroquinone or a chain transfer agent such as dodecyl mercaptan may be used.

In addition, to promote grafting, it is effective to introduce polymerizable double bonds or graftable chemical bonds into the epoxy resin.For example, acrylic acid, acrylamide, etc. , methylol acrylamide,
Butoxymethylacrylamide, hydroxyethyl methacrylate, glycidyl methacrylate, maleic anhydride, monoethyl itaconate, motuptyl fumarate, chloromethylstyrene, phosphoxyethyl methacrylate, chlorohydroxypropyl methacrylate, rose hydroxystyrene, dimethylaminoethyl A typical method is to react a compound having a functional group and a polymerizable double bond, such as methacrylate, with an epoxy resin in advance.

In the present invention, the epoxy resin or the vinyl polymer may remain free in the graft polymer without being grafted.

The modified epoxy resin (a) can be obtained by addition-reacting an addition-reactive silicone polymer in the presence of the above-mentioned graft polymer of an epoxy resin and a vinyl polymer, or by adding a silicone polymer to form a soft vinyl polymer. In other words, addition-reactive silicone rubber is obtained by polymerizing a vinyl-modified silicone polymer with a vinyl group in its molecule and a hydrogen-modified silicone polymer with an active hydrogen in its molecule through a silylation reaction. Rubber produced by reaction,
The particle size is 1.0μ or less, preferably 0.5μ or less,
More preferably, it is 0.01 tt or more and 0.2 μ or less. If the particle size of the silicone rubber exceeds 1.0 μm, the object of the present invention, which is to reduce stress, cannot be achieved and thermal shock resistance cannot be improved.

A vinyl-modified silicone polymer is a polysiloxane having at least one 5t-CH-CRz bond at the end or inside the molecule, and a hydrogen-modified silicone polymer is a polysiloxane having at least one 5t-CH-CRz bond at the end or inside the molecule.
Polysiloxanes having at least two H bonds are usually commercially available in combination; examples of these include 5E-1 from Toray Silicone Co., Ltd.
821, KE of Shin-Etsu Chemical Co., Ltd., and 1204.

The particle size of silicone rubber obtained by addition reaction can also be controlled by the amount of double bonds introduced into the epoxy resin.

Further, the soft vinyl polymer can be obtained by polymerizing monomers that form a soft vinyl polymer by a conventional method.

The soft vinyl polymer used in the present invention must be a polymer mainly composed of vinyl-modified silicone.The polymer mainly composed of vinyl-modified silicone is a homopolymer or copolymer of vinyl-modified silicone. Examples of the vinyl-modified silicone, which refers to a copolymer of a vinyl-modified silicone and another vinyl monomer, include methacryloxypropylsiloxane, methacryloxypropylalkoxysilane, and vinylalkoxysilane. Furthermore, as other vinyl monomers, all the monomers used in preparing the graft polymers mentioned above can be used. The proportion of other monomers to be used is such that the resulting copolymer is soft, ie liquid or rubbery, and has a particle size of 1.0μ or less, and usually accounts for the proportion of all monomers, although it depends on the type of monomer. It is less than 1% in 8 cases.

In order to achieve the object of the present invention of reducing stress and improving impact resistance, the particle size of the soft vinyl polymer should be 1.0μ or less, preferably 0.5a or less, and more preferably 0.01μ.
It is 0.2u or less. If the particle size of the soft vinyl polymer exceeds 1.0μ, stress reduction cannot be achieved and thermal shock resistance cannot be improved.The particle size of the soft vinyl polymer cannot be controlled by using the vinyl polymer that forms a graft polymer with the epoxy resin. This can be controlled by selecting the type, amount, and composition of the monomers forming the soft vinyl polymer, but it can also be controlled by the amount of double bonds introduced into the epoxy resin.

The amount of the modified epoxy resin used is in the range of 0.1 to 10, preferably 0.1 to 10, in terms of equivalent ratio to (c) the phenol alkyl resin and/or the resorcin alkyl resin described below.
It is in the range of 5 to 2.0.

The composition of the present invention may contain an unmodified epoxy resin if desired. As the unmodified epoxy resin, all the epoxy resins used in (a) of the present invention can be used, and even if both are the same, Well, they can be different.

In addition, the amount of silicone polymer (the amount of silicone rubber and/or soft vinyl polymer obtained by addition reaction) must be 5% by weight or more based on the total of the modified epoxy resin (a) and the epoxy resin used if desired. ,
In particular, 10 to 50% by weight is preferable. If it is less than 5% by weight, low stress cannot be achieved. To adjust the amount of silicone polymer to a desired amount, the vinyl monomer used when producing the modified epoxy resin (a) Although the amount of the unmodified epoxy resin may be adjusted, it is easier to do so by changing the amount of the unmodified epoxy resin, and from this point of view as well, it is preferable to use the unmodified epoxy resin in combination.

The bismaleimide compound (b) used in the present invention is represented by general formula (1).

(R represents a divalent organic group having at least 2 carbon atoms) Such bismaleimide compounds include, for example, N
, N'-ethylene bismaleimide, N, N'-hexamethylene bismaleimide, N, N'-m-phenylene bismaleimide, N, N'-p-phenylene bismaleimide, N, N'-4,4'- diphenylmethane bismaleimide, N,N'-4,4'-diphenyl ether bismaleimide, N,N'-methylenebis(3-chloro-p-
phenylene) bismaleimide, N, N'-4,4'-
Diphenylsulfone bismaleimide, N, N'-4,
4°-Dicyclohexylmethane bismaleimide, N, N
Examples include "-α,α'-4,4"-dimethylenecyclohexane bismaleimide, N+N'm-methaxylene bismaleimide, N,N'-4,4°-diphenylcyclohexane bismaleimide, and the like.

In the present invention, one or more of the above bismaleimide compounds can be used. Moreover, maleimide compounds other than those mentioned above can be used in combination as necessary.

The amount of the bismaleimide compound used in the composition of the present invention is usually 30 to 80% by weight.

The aralkyl resin used in the present invention has two or more active OH groups and has R3R in its molecular structure.

has as a repeating unit. Phenol aralkyl resin is a resin obtained by reacting an aralkyl ether with phenol, and a specific example thereof is Zylock>[L-225 (Mitsui Toatsu Kagaku ■, softening point: 85°C to 105°C). Moreover, the resorcin aralkyl resin used in the present invention is a resin made by reacting an aralkyl ether with resorcin, and specifically, resorcin Zyloc (Mitsui Toatsu Chemical ■, softening point 85°C ~
105°C).

The amount of these aralkyl resins used is usually in the range of 10 to 500 parts by weight per 1 part of bismaleimide compound 100fE.

Furthermore, it is also possible to use phenols other than those mentioned above in combination, if necessary.

Examples of the inorganic filler (d) used in the present invention include powders such as crystalline silica, fused silica, alumina, talc, calcium silicate, calcium carbonate, mica, clay, and titanium white, or glass fibers and carbon fibers. From the viewpoint of thermal expansion coefficient, thermal conductivity, etc., crystalline, meltable, etc. silica powder is usually used, and the blending amount is 100 parts by weight per 100 parts by weight of the resin composition @ff. -600 parts by weight is preferable, and if it is less than 100 parts by weight, the coefficient of thermal expansion is large (and good impact resistance cannot be obtained).

Moreover, if it exceeds 600 parts by weight, the fluidity of the resin decreases and moldability deteriorates, making it difficult to put it into practical use.

In order to produce the resin composition in the present invention, each component may be blended and kneaded by a conventional method, or it may be a librevolimer in which a maleimide compound is dissolved in a 7ralkyl resin in advance, especially when a prepolymer is used. It has excellent moldability and hardenability.

In the present invention, when curing the resin composition, it is preferable to use phosphines as a curing accelerator. Examples of the phosphines include triphenylphosphine, tri-4-methylphenylphosphine, tri-4-methoxyphenylphosphine, tributylphosphine, Examples include trioctylphosphine and tri-2-cyanoethylphosphine. The amount of phosphines used is the total amount of modified epoxy resin, maleimide resin, phenol aralkyl resin, and or resorcin aralkyl resin.
It is preferably 0.1 to 10 parts by weight per 00 parts by weight.

Further, an organic peroxide or an azo compound can be used in combination if necessary. Examples of organic peroxides include di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 1.3-bis-(L-butylperoxy-isopropyl)benzene, 1.1-di- Examples include dialkyl peroxides such as t-butylperoxy-3,3,5-)limethylcyclohexane and 1,1-di[-butylperoxycyclohexane, and alkyl peresters such as t-butylperbenzoate. Examples of the azo compound include azobisisobutyronitrile and azobisdimethylvaleronitrile.

The amount of the organic peroxide or azo compound added is preferably 0.1 to 5 parts by weight per 100 parts by weight of the bismaleimide compound.

Furthermore, imidazoles, tertiary amines,
class ammonium salt, organometallic compound, tris(3,6-
A curing accelerator such as tri(polyoxyalkyl)amines represented by cyoxyhebutyl)amine can also be used in combination. Particularly when using a prepolymer of a maleimide compound and phenol, tri(°polyoxyalkyl)amines are preferred.

In addition to the above-mentioned compositions, the composition of the present invention may contain amines, various reaction diluents, silicone oil, silane coupling agents, mold release agents, coloring agents, flame retardants, etc. as necessary, and is then mixed, kneaded, and molded. Use as a material.

〔Example〕

(Production of modified epoxy resin) Production Example 1 100 parts of orthocresol novolac epoxy resin (epoxy equivalent: 217), 10 parts of toluene, and 1 part of methacrylic acid were reacted at 120 to 125°C for 2 hours in the presence of a tertiary amine. After that, 5 parts of butyl acrylate, 10 parts of methacryloxypropyl silicone oligomer (manufactured by Shin-Etsu Chemical Co., Ltd.), 0.4 parts of azobisisovaleronitrile,
100 parts of ethyl acetate is reacted at 75°C for 4 hours. Furthermore, as addition reaction type silicone polymers, 10 parts of vinyl-modified polysiloxane and 10 parts of hydrodiene-modified polysiloxane (both KE-1204 manufactured by Shin-Etsu Chemical Co., Ltd.) were added.
) was added, stirred vigorously, and reacted for 2 hours. Then 1 more
The solvent was removed under reduced pressure at 30"C, and the particle size was 0.2-0.
Modified epoxy resin (a
-1) (epoxy equivalent: 295) was obtained.

Production Example 2 Same as Production Example 1 except that the amount of methacrylic acid used in Production Example 1 was 1.2 parts, and the amounts of vinyl-modified polysiloxane and hydrogen-modified polysiloxane were each 30 parts. The particle size is 0.2 to 0.
Modified epoxy resin (a
-2) (Epoxy equivalent: 320) was obtained.

Production Example 3 Orthocresol novolac epoxy resin (epoxy weight! 21?) 100 parts, toluene 10 parts, methacrylic M
After reacting 1 part in the presence of a tertiary amine at 120-125°C for 2 hours, 3.6 parts of butyl acrylate, 0.1 part of glycidyl methacrylate, 2 parts of t-butylperoxy
- 0.05 part of ethylhexanoate is reacted at 100°C for 1 hour. Furthermore, 30 parts of methacryloxypropyl siloxane, 0.0 parts of neopentyl glycol diacrylate.
6 parts, 1,1-bis(t-butylperoxy)3,3.
5-) After reacting for 4 hours while continuously adding 0.15 parts of cyclohexane dropwise, and then reacting for another 4 hours, the solvent was removed under reduced pressure, and a soft vinyl polymer with a particle size of 0.2 to 0.5μ was dispersed. A modified epoxy resin (a-3) (epoxy equivalent: 295) was obtained.

Production Example 4 The amount of methacrylic acid used in Production Example 3 was 1.2 parts, the amount of butyl acrylate was 5.0 parts, the amount of methacryloxypropylsiloxane was 55 parts, and the amount of neopentyl glycol diacrylate was 1.0 parts. A modified epoxy resin (a, -4) (epoxy equivalent: 315) in which a soft vinyl polymer having a particle size of 0.2 to 0.5 μm was dispersed was obtained in the same manner as in Production Example 3 except that

Comparative Production Example 1 100 parts of orthocresol novolak epoxy resin (epoxy equivalent: 21?), 100 parts of toluene, and 5 parts of a silane coupling agent (T-glycidoxypropyltrimethoxysilane, manufactured by Toshi Silicone Co., Ltd.) were kept at 75°C. , addition reaction silicone polymer (manufactured by Toshi Silicone Co., Ltd.) 30
The mixture was stirred vigorously and reacted for 2 hours. then 130
The solvent was removed under reduced pressure at <RTIgt;C,</RTI> to obtain a modified epoxy resin (a-5) (epoxy equivalent: 295) in which silicone rubber having a particle size of 1 to 5 microns was dispersed.

Examples 1 to 7 Modified epoxy resin, bismaleimide compound, phenol aralkyl resin, resorcin aralkyl resin, curing accelerator, organic peroxide, quaternary ammonium salt, silica powder, silane coupling agent with the formulations shown in Table 1. , wax, colorant, and flame retardant were blended and roll-kneaded to obtain a molding material.

Comparative Examples 1 to 5 Molding materials were obtained by blending and kneading modified epoxy resins, bismaleimide compounds, and phenol resins in combinations different from those in the examples in the formulations shown in Table 1 in the same manner as in the examples.

Comparative Example 6 A molding material was obtained by blending and kneading an epoxy resin and a novolak phenol resin in the same manner as in the examples, according to the formulation shown in Table 1.

Using each molding material, transfer molding (180"C,
30kg/cd for 3 minutes) to test a 100-pin flat package (20-ugly x 30ma x 2
゜5mm, 12m1wXI2*a+ test element base!
Test pieces for three-dimensional and physical property measurements were molded and post-cured at 180°C for 6 hours.

The test results are shown in Table-2.

〔Effect of the invention〕

As explained in the examples and comparative examples, according to the present invention,
It has a higher glass transition temperature and lower thermal expansion than the conventionally used sealing resins mainly composed of polyfunctional epoxy resins and novolak phenol resins. In addition, compared to sealing resins containing bismaleimide compounds and phenolic resins as main components other than the combination of the present invention, it has a lower water absorption rate, more flexibility, and lower stress. Only the examples of the present invention have excellent heat resistance.

When this resin composition is used for sealing a large-sized semiconductor device with a high degree of integration or a semiconductor device for surface mounting, excellent reliability can be obtained, and it can be said that this invention is industrially useful.

Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (2)

[Claims] (1) (a) Modified epoxy resin in which silicone polymer is uniformly dispersed in a graft polymer of epoxy resin and vinyl polymer with a particle size of 1.0 μ or less, (b) Bismaleimide compound (c) Phenol aralkyl resin and/or a resorcinol aralkyl resin; and (d) an inorganic filler. (2) The resin composition for semiconductor encapsulation according to claim 1, wherein the silicone polymer is a silicone rubber obtained by reacting an addition reaction type silicone polymer and/or a soft vinyl polymer mainly composed of a vinyl-modified silicone polymer.