KR0177305B1 - Epoxy resin composition for encapsulating semiconductor device - Google Patents

Abstract

The present invention relates to an epoxy resin composition for semiconductor sealing in which thermal shock resistance and crack resistance are improved in order to increase reliability of a semiconductor device, and includes an epoxy resin, a phenol resin, an imide-modified silicone compound, an inorganic filler, a curing accelerator, and a coupling agent. In the epoxy resin composition described above, the composition further comprises an adhesive force-providing agent comprising at least two kinds of mixtures selected from polyvinyl alcohol, polychloroprene, phenol and alkyl styrene resin.

Description

[Name of invention]

Epoxy Resin Compositions for Semiconductor Device Sealing

Detailed description of the invention

The present invention relates to an epoxy resin composition for sealing semiconductor elements, which has improved reliability by improving high temperature heat resistance and crack resistance.

Conventionally, ceramics, glass, or metals have been used to seal semiconductor devices such as transistors, integrated circuits (ICs), highly integrated circuits (LSI), and ultra-high integrated circuits (VLSI), but they are expensive and not suitable for mass production. It is used only in some limited areas such as uses, and in recent years, thermosetting resins such as epoxy, silicone, phenol, imide and phthalate are used instead of these materials. In particular, epoxy resins are widely used for sealing electrical and electronic components and semiconductor devices requiring high reliability because they have superior electrical insulation, mechanical properties, heat resistance, and moisture resistance than other resins.

Recently, as the degree of integration of semiconductor devices increases, the size of semiconductor chips is increasing, and the trend of multipinning is due to the transfer of a great deal of information. However, miniaturization and thinning are being performed along with the proliferation of surface mount packages. For example, in the case of a highly integrated memory device, a semiconductor chip has an area of 200 mm and a thickness of 1.0 mm or less, and an ASIC quad flat package (ASIC) has about 500 pins. When the semiconductor device is surface mounted, heat is applied at 215-260 ° C., so internal stress may occur. Also, the resin composition, leadframe, and die paddle may be caused by evaporation of moisture absorbed from the outside during package storage. Moisture resistance may be reduced due to peeling between the paddles, and in more severe cases, may cause package cracks. In order to prevent such defects, the semiconductor industry is dealing with strict humidity control such as moisture-proof bales, but the quality that does not generate package cracks is strongly required for the encapsulant itself.

The epoxy resin composition used for the sealing of a conventional semiconductor device has reduced the internal stress by using a silicone modified resin, but the moldability and poor moisture resistance due to the viscosity increase during sealing. In addition, due to the high filling of the fillers, the coefficient of linear expansion and the water absorption rate were reduced to suppress the occurrence of cracks during surface mounting of the semiconductor package. The filling problem occurs and the voids inside and outside the package are increased. On the other hand, attempts were made to improve the fluidity of the composition using low viscosity resins, but the crosslinking density of the resins was lowered, resulting in deterioration of basic properties such as heat resistance, moldability, and release property.

Accordingly, the present invention provides an epoxy resin composition for semiconductor encapsulation, which has significantly improved thermal shock resistance and crack resistance than conventional epoxy resin compositions, while satisfying moisture resistance, mechanical strength, moldability, and the like, which are generally required for semiconductor encapsulating resin. It aims to provide.

In order to achieve the above object, in the present invention, in an epoxy resin composition comprising an epoxy resin, a phenol resin, an imide-modified silicone compound, an inorganic filler, a curing accelerator, and a coupling agent, polyvinyl alcohol, polychloroprene, phenol, and alkyl styrene It provides the epoxy resin composition for semiconductor element sealing characterized by further including the adhesiveness imparting agent which consists of a mixture of at least 2 types of resin.

Hereinafter, the present invention will be described in detail.

The epoxy resin composition for semiconductor element sealing of the present invention is characterized by further including an adhesive agent other than the component usually used.

As an adhesive agent, at least two selected from polyvinyl alcohol, polychloroprene, phenol, and alkyl styrene resin may be mixed and used, and it is preferable to use 0.01-6 parts by weight based on the total composition, more preferably 0.1 -5 parts by weight. When 0.01 weight part or less is used, the crack resistance effect does not appear correctly, and when it exceeds 6 weight part, the characteristic of the resin composition main material falls. In addition, it is preferable that the polyvinyl alcohol and the polychloroprene have a molecular weight of 1000-100,000, and 10-70 parts by weight of polyvinyl alcohol, 5-85 parts by weight of polychloroprene, and 3-40 of phenol with respect to the total adhesion agent. It is preferable to use a weight part and alkyl styrene resin at 10-70 weight part.

As the epoxy resin in the composition of the present invention, a cresol novolac epoxy resin containing two or more epoxy groups in a molecule or at the terminal, a biphenyl epoxy resin, a high heat resistant resin into which a naphthalene group is introduced, and the like can be used. At this time, the epoxy resin is equivalent to 150-320, the impurity content is preferably 200ppm or less, it can be used in an amount of 5-20 parts by weight. If the concentration of hydrolyzable chlorine ions is 200 ppm or more as an impurity, corrosion of the aluminum wiring or the like in the sealed semiconductor element is promoted, which is not preferable. If the epoxy equivalent is 300 or more, the crosslinking density decreases, resulting in a decrease in heat resistance and mechanical strength. If the epoxy equivalent is 150 or less or a softening point of 54 ° C. or less, flashing is remarkable. Difficulties in sealing work.

In the composition of the present invention, the phenol resin serves as a curing agent, and a phenol resin, a phenol aralkyl resin, a phenol dicyclopentadiene resin, etc., having a softening point of 70-110 ° C. and containing two or more hydroxy groups in a molecule may be used. The phenol resin may be used in an amount of 3 to 15 parts by weight, and the ratio of the phenolic hydroxy group to the number of epoxy groups in the epoxy resin is preferably 0.5-1.5, more preferably 0.7-1.3. Outside the said range, reaction does not fully advance and the characteristic of hardened | cured material, such as heat resistance and moisture resistance, falls.

The imide-modified silicone compound used in the composition of the present invention serves as a plasticizer for lowering stress, and may be prepared, for example, by reacting an imide with a polysiloxane containing an amine group. The blending ratio of this component is preferably 0.2-6 parts by weight of the total composition. When it is less than 0.2 parts by weight, the effect of lowering stress does not appear properly. When it exceeds 6 parts by weight, the glass transition temperature of the resin composition is lowered to lower the heat resistance. May result.

Inorganic fillers that may be used in the compositions of the present invention include fused silica powder, crystalline silica powder, glass fiber, alumina powder, magnesia powder, silicon oxide, tar, asbestos, and the like. Most preferred in terms of high density and low coefficient of linear expansion. The blending amount of the filler depends on the type of the epoxy resin, the curing agent and the inorganic filler, but in order to apply to the transfer molding process, it is preferable to use 65-90 parts by weight of the total composition. When 65 parts by weight or less is used, thermal expansion is increased, and physical properties such as heat resistance, crack resistance, and moisture resistance are decreased. When 90 parts by weight or more is used, fluidity is decreased, and the warpage of the bond wire connecting the semiconductor element and the lead frame, Cutting occurs and, in more severe cases, sealing is impossible.

Examples of curing accelerators that can be used in the compositions of the present invention include organic phosphine-based compounds, and examples thereof include tertiary phosphines such as triphenyl phosphine, tributyl phosphine, tricyclohexyl phosphine, and methyldiphenyl phosphine. Secondary phosphine compounds such as compounds, butylphenyl phosphine and diphenyl phosphine, and primary phosphine compounds such as phenyl phosphine and octyl phosphine. Among them, triphenyl phosphine is most preferred in terms of reliability. It is preferable to use a hardening accelerator 0.1-1.0 weight part with respect to the whole composition.

Coupling agents used in the surface treatment of inorganic fillers in the composition of the present invention include silane-based compounds containing epoxy, mercapto, vinyl and amine functional groups, and the amount thereof is preferably 0.1-2 parts by weight.

In addition to the above-mentioned components, it is preferable to mix | blend suitably the usual additives, such as a flame retardant, a coloring agent, a mold release agent, with the composition of this invention.

As the organic flame retardant, a bromine-substituted cresol novolak-type epoxy resin or a bisphenyl-based epoxy resin can be used, and the amount thereof is preferably 0.8-5 parts by weight. Examples of the inorganic flame retardant include antimony trioxide, the amount of which is preferably blended within the range of 0.5-5 parts by weight depending on the amount of the organic flame retardant, and preferably having a particle size distribution within the range of 1-15 μm.

Carbon black is mentioned as a coloring agent, and it is preferable to use it at 0.1-1 weight part. If it is less than 0.1 part by weight, the desired chromaticity may not be obtained, and if it is 1.0 parts by weight or more, the electrical properties of the encapsulant may be reduced.

As the release agent, natural waxes, synthetic waxes, higher fatty acids and metal salts, acid amide esters, paraffins, and the like may be used alone or in combination, and preferably 0.1-2 parts by weight.

The epoxy resin composition for semiconductor encapsulation of the present invention can be uniformly mixed by using a mixing device such as a roll mill (kneader), etc. required components to be produced as a molding material, the mixing method is a special limitation However, since the mixing agent and the plasticizer imparting to the epoxy resin or the phenol resin at high temperature can be added to improve the dispersibility and improve the heat resistance and the thermal shock resistance, silica is preferably used in the high speed mixer. It is preferable to spray and surface-treat and then add.

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following Examples.

[Examples and Comparative Examples]

Each component was blended with the components and composition ratios shown in Table 1 below, followed by heat melting and kneading with a roll mill, cooling, and then pulverizing them to a constant particle size to prepare a molding material.

1. Epoxy Resin

I: ortho-cresol novolac epoxy resin having an epoxy equivalent of 198 and a softening point of 66 ° C. (trade name: Japanese Chemical Company EOCN-65)

II: Biphenyl epoxy resin whose epoxy equivalent is 192 and softening point of 107 degreeC (brand name: Yucca shell company YX-4000H)

2. Coupling Agent

III: epoxy silane resin, glycidoxy propyl trimethylsilane

IV: amine silane resin, aminopropyltriethoxysilane

3. Phenolic Resin: Phenolic novolac resin having a hydroxy equivalent weight of 107 and a softening point of 85 ° C. (trade name: Meiwasa HF-1).

4. Imide modified silicone resin: diphenylmethane bismaleimide dimethylsilonic acid

5. Inorganic filler: A mixture of pulverized fused silica having a particle size of 5-15 μm and spherical silica having a particle size of 20-40 μm at 3: 7.

6. Curing accelerator: triphenyl phosphine

7. Organic flame retardant: BREN-S

8. Inorganic flame retardant: SbO

9. Colorant: Carbon Black

10. Release agent: Carnauba wax

11.Adhesive Agent

Polyvinyl alcohol: Polyvinyl alcohol with a molecular weight of 3,000

Polychloroprene: Dupont, neoprene latex 115

Phenol: a-ethylbenzyl alcohol

Alkyl styrene: a-methyl styrene (Hercures Krystalex)

The molding material obtained above was molded under the conditions of 170-180 ° C., 70 kg / cm 2, and 90-120 seconds using a transfer molding machine, and after curing for 4 hours at a temperature of 170 ° C. or higher, a test piece was prepared. The physical properties were measured under the conditions.

(1) flexural strength and flexural modulus

Specimens were prepared according to ASTM D790 and measured using UTM (Zwick Z010).

(2) glass transition temperature

The TMA (Seiko, SSC5200) measurement equipment was used to increase the temperature to 1-2 ° C. per minute.

(3) coefficient of linear expansion

Measurement was made using a TMA measuring instrument.

(4) moisture absorption rate

The prepared specimens were left for 168 hours in an atmosphere of 85 ° C./85% water vapor, and then the weight change was measured and expressed as a percentage of the initial weight.

(5) thermal shock test

The sample device was repeatedly immersed for 30 seconds in a liquid of -195 ° C and a liquid of 230 ° C for 30 seconds, and the cracks inside and outside the specimen were observed with an optical microscope and an ultrasonic tomography. Was measured.

The test results are shown in Table 2 below.

As shown in Table 2, it can be seen that the molded article prepared from the epoxy resin composition of the present invention has superior thermal shock resistance and crack resistance compared to the molded article prepared from the resin composition of Comparative Example. Therefore, the epoxy resin composition of the present invention is useful for high density surface mount package sealing.

Claims (5)

In an epoxy resin composition comprising an epoxy resin, a phenol resin, an imide-modified silicone compound, an inorganic filler, a curing accelerator, and a coupling agent, at least two kinds of mixtures selected from polyvinyl alcohol, polychloroprene, phenol, and alkyl styrene resins. An epoxy resin composition for sealing a semiconductor element, further comprising an adhesion imparting agent. The composition according to claim 1, wherein the adhesion agent is used in an amount of 0.01-6 parts by weight based on the total resin composition. The composition according to claim 1, wherein the molecular weight of the polyvinyl alcohol and the polychloroprene used as the adhesion imparting agent is 1000-10,000. The polyvinyl alcohol is used in an amount of 10 to 70 parts by weight, 5 to 85 parts by weight of polychloroprene, 3 to 40 parts by weight of phenol and 10 to 70 parts by weight of the alkylstyrene resin, based on the total amount of the adhesion agent. Characterized in that the composition. The bismaleimide group of the imide-modified silicone compound according to claim 2, wherein N, N'-1,3-diphenylether maleimide, N, N'-4,4'-diphenylsulfone bismaleimide, N, N'-4,4'-dicyclohexylmethane bismaleimide, N, N'-4,4'-dimethylcyclohexane bismaleimide, N, N'-4,4'-diphenylcyclohexane bismaleimide , N, N'-1,3'-xylide bismaleimide, 2,4-bismaleimide toluene or 2,6-bismaleimide toluene.