KR100474961B1 - Epoxy resin composition for encapsulating semiconductor device - Google Patents

Abstract

The present invention relates to an epoxy resin composition for sealing semiconductor elements, more specifically

(1) having two or more epoxy groups and having an epoxy equivalent of 100 to 220

   Epoxy resin 3.5-10.0% by weight,

(2) having two or more hydroxyl groups and having a hydroxyl equivalent weight of 100 to 200;

   Hardener 2.0-10.0 wt%,

(3) 0.1 to 0.5% by weight curing accelerator,

(4) 80.0-91.0 weight% of inorganic fillers, and

(5) Other additives 3.365-10.0 wt%

In the epoxy resin composition for semiconductor element sealing comprising a 0.035 to 3.0% by weight of the adhesion strength enhancer of the formula (1) relates to an epoxy resin composition for semiconductor element sealing, the epoxy resin composition of the present invention is a lead Since the adhesive strength with the frame is improved and the moisture resistance is excellent, sealing of the semiconductor element with the composition of the present invention can suppress crack generation.

[Formula 1]

(Wherein R is an ethyl group or a methyl group and n is 0 to 3)

Description

Epoxy resin composition for encapsulating semiconductor device

The present invention relates to an epoxy resin composition for sealing semiconductor elements, and more particularly, to an epoxy resin having two or more epoxy groups and having an epoxy equivalent of 100 to 220, a curing agent having two or more hydroxyl groups and having a hydroxyl equivalent of 100 to 200, and curing The present invention relates to an epoxy resin composition for sealing a semiconductor device, including an accelerator, an inorganic filler, and an adhesion enhancing agent of the following Chemical Formula 1, and having excellent adhesion strength and moisture resistance to a semiconductor device lead frame.

(Wherein R is an ethyl group or a methyl group and n is 0 to 3)

In recent years, the degree of integration of semiconductor devices has been improved day by day, and thus the size of wirings, the size of devices and the size of multilayer wirings are rapidly progressing. On the other hand, in the case of the package which protects a semiconductor element from an external environment, compactness and thinning are accelerating from the viewpoint of high-density mounting to a printed board, ie, surface mounting.

As described above, in the resin encapsulated semiconductor device in which a large semiconductor device is sealed in a small and thin package, the frequency of failure due to package cracks is very high due to thermal stress caused by temperature and humidity changes in the external environment. Therefore, in order to solve such a problem, there is a strong need to develop a method for improving the reliability of the epoxy resin molding material for sealing semiconductor devices, and as a specific method, a method of lowering elastic modulus for reducing stress and thermal expansion A method of lowering the coefficient, improving adhesion and preventing moisture penetration through the interface between the lead frame and the epoxy resin composition and interfacial peeling due to heat cycle, and a method of reducing the moisture absorption by high filling of the inorganic filler have been proposed. come.

Among the above-mentioned methods, a method of lowering the modulus of elasticity is a method of modifying an epoxy resin composition by blending a butadiene-containing rubber modifier or a silicone polymer having excellent thermal stability (see Japanese Patent Application Laid-Open Nos. 63-1894 and 5-291436). There is). Since the silicone polymer is incompatible with the epoxy resin and the curing agent, which are the base resins of the molding material, the silicone polymer can be dispersed in the form of fine particles in the base resin to lower the elastic modulus while maintaining the heat resistance.

As a method of lowering the coefficient of thermal expansion, there is a method of increasing the filling amount of the inorganic filler having a low coefficient of thermal expansion. In this case, as the filling amount of the inorganic filler is increased, the fluidity of the epoxy molding material is lowered and the elasticity is increased. Japanese Patent Laid-Open No. 64-11355 discloses a technique for using a spherical filler but blending a large amount of filler by controlling its particle size distribution and particle size. In this case, as the content of the inorganic filler increases, the effect of lowering the moisture absorption rate can be obtained.

Finally, as a method of strengthening the adhesive strength between the epoxy resin sealant and the lead frame, there are not many proposals so far, but a method of applying a high adhesive epoxy resin or a curing agent is most widely used. However, the epoxy resin and the curing agent alone has a limit in improving the adhesive strength, so the development of more effective adhesion enhancer is required.

An object of the present invention is to solve the problems of the prior art as described above, by adding a compound of the formula (1) as an adhesion enhancer between the epoxy resin composition and the lead frame epoxy resin composition for semiconductor device sealing improved adhesion strength and moisture resistance reliability To provide.

That is, the present invention

(1) having two or more epoxy groups and having an epoxy equivalent of 100 to 220

   Epoxy resin 3.5-10.0% by weight,

(2) having two or more hydroxyl groups and having a hydroxyl equivalent weight of 100 to 200;

   Hardener 2.0-10.0 wt%,

(3) 0.1 to 0.5% by weight curing accelerator,

(4) 80.0-91.0 weight% of inorganic fillers, and (5) 3.365-10.0 weight% of other additives.

In the epoxy resin composition for sealing a semiconductor device comprising a, to provide an epoxy resin composition for sealing semiconductor device comprising 0.035 to 3.0% by weight of the adhesion strength enhancer of the formula (1).

[Formula 1]

(Wherein R is an ethyl group or a methyl group and n is 0 to 3)

The epoxy resin composition for sealing a semiconductor device of the present invention includes an epoxy resin, a curing agent, a curing accelerator, an inorganic filler, and an adhesion enhancing agent, which will be described in detail below.

The epoxy resin (hereinafter referred to as component (1)) used in the present invention is a high purity epoxy resin having two or more epoxy groups and having an epoxy equivalent of 100 to 220 and an impurity content of 10 ppm or less, and a conventional ortho cresol novolac resin, Biphenyl epoxy resins, bisphenol A resins, or mixtures thereof. In the case where two or more kinds of the epoxy resins are mixed and used, it is preferable to use a biphenyl epoxy resin having an epoxy equivalent of 190 to 200 with respect to the whole epoxy resin mixture in an amount of 40% by weight or more in terms of adhesion and moisture resistance.

The content of component (1) is preferably 3.5 to 10.0% by weight based on the total composition. If the content is less than 3.5% by weight can not be obtained because the physical properties of the degree required by the present invention is not good, if it exceeds 10.0% by weight is not economical because it is not good.

The curing agent used in the present invention (hereinafter referred to as component (2)) is a conventional phenol novolak resin, xylok resin, dicyclopentadiene resin having two or more hydroxyl groups and having a hydroxyl equivalent of 100 to 200 or their Mixture. When two or more kinds of the curing agents are mixed and used, it is preferable to use 40% by weight or more of the xylok resin with respect to the entire curing agent mixture in terms of adhesion and moisture resistance.

The content of the component (2) is determined so that the composition ratio of the epoxy equivalent of the component (1) to the hydroxyl equivalent of the component (2) falls within the range of 0.8 to 1.3. At this time, the content of the component (2) is equivalent to 2.0 to 10.0% by weight based on the total composition, if out of the above range, a large amount of unreacted epoxy groups and phenol groups are generated, which results in poor reliability.

The curing accelerator used in the present invention (hereinafter referred to as component (3)) is a component necessary for promoting the curing reaction of the component (1) and the component (2), for example benzyldimethylamine, triethanolamine, triethylene Tertiary amines such as diamine, dimethylaminoethanol and tri (dimethylaminomethyl) phenol; Imidazoles such as 2-methylimidazole and 2-phenylimidazole; Organic phosphines such as triphenylphosphine, diphenylphosphine and phenylphosphine; And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate, and one or two or more thereof may be mixed and used.

The content of the component (3) is preferably 0.1 to 0.5% by weight based on the total composition. When the content is less than 0.1% by weight, the curing rate is slow and the productivity is not good, and when the content is more than 0.5% by weight, the desired curing properties are not obtained and storage stability is not good.

As the inorganic filler (hereinafter referred to as component (4)) used in the present invention, it is preferable to use fused or synthetic silica having an average particle size of 0.1 to 35.0 µm. The type of the silica is preferably a mixed type in which the composition ratio between the crushed type and the spherical type is 7/3 to 0/10.

The content of the component (4) is preferably 80.0 ~ 91.0% by weight based on the total composition. If the content is less than 80.0% by weight, sufficient strength and numerical stability against high temperature may not be obtained, and the penetration of moisture may be facilitated, so that popcorn cracks are generated in the high temperature solder process. On the other hand, if the content is more than 91.0% by weight is not good because there is a fear that the flow properties of the composition is deteriorated to deteriorate formability.

In the present invention, the compound of formula 1 is used as an adhesion enhancer between the semiconductor element sealing material and the lead frame, and the adhesion enhancer is applied by direct injection or spraying during preparation of the epoxy resin composition.

[Formula 1]

(Wherein R is an ethyl group or a methyl group and n is 0 to 3)

The content of the adhesion enhancer is determined to be 1 to 30 parts by weight based on 100 parts by weight of the epoxy resin of component (1), wherein the content of the adhesion enhancer corresponds to 0.035 to 3.0% by weight based on the total composition. When the content is less than 1 part by weight based on 100 parts by weight of epoxy resin, sufficient high adhesion strength and moisture resistance may not be expressed. When the content is more than 30 parts by weight, stability at room temperature may be reduced, mold contamination and fluidity due to bleed. It is not good because it can cause degradation.

In addition, the epoxy resin composition of the present invention includes a flame retardant such as brominated epoxy; Flame retardant aids such as antimony trioxide, alumina hydroxide and antimony pentoxide; Mold release agents such as higher fatty acids, higher fatty acid metal salts, and ester waxes; Coloring agents such as carbon black, organic and inorganic dyes; Coupling agents, such as an epoxy silane, an amino silane, and an alkyl silane, etc. can be added in 3.365 to 10.0 weight% of the whole composition as needed.

The epoxy resin composition of the present invention is uniformly mixed using the above-mentioned components using a Henssel mixer or Loedige mixer, and then melt kneaded with a roll mill or kneader, cooled and It is prepared as a final powder product after grinding.

As a method of sealing a semiconductor device using the epoxy resin composition prepared as described above, a low pressure transfer molding method is most commonly used, but molding may also be performed by injection or casting.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example  1 ~ 2

After weighing each component as shown in Table 1 below, the mixture was uniformly mixed with a Henschel mixer to prepare a powdery primary composition, melt-kneading at 100 ° C. for 7 minutes using a mixing 2-roll mill, and then cooled and Through the grinding process to prepare a final epoxy resin composition. The physical properties of each of the epoxy resin compositions thus obtained were evaluated, and the evaluation results are shown in Table 1 below.

Comparative example  1 ~ 2

After weighing each component as shown in Table 1 below, an epoxy resin composition was prepared in the same manner as in Example. The physical properties of each of the epoxy resin compositions thus obtained were evaluated, and the evaluation results are shown in Table 1 below.

                                                      (Unit: parts by weight) Composition Example 1 Example 2 Comparative Example 1 Comparative Example 2 Biphenyl epoxy resin 50 85 50 85 o-cresol novolac epoxy resin 35 - 35 - Brominated epoxy 15 15 15 15 Phenolic Novolak Resin 30 - 30 - Xylox Resin 20 50 20 50 Triphenylphosphine 2 4 2 4 Silica 1000 1000 1000 1000 Adhesion Enhancer of Formula (1) 10 25 - - γ-glycithoxypropyltrimethoxysilane 4 4 4 4 Epoxy Modified Silicone Oil 3 3 3 3 Carbon black 3 3 3 3 Carnauba Wax 4 4 4 4 Antimony trioxide 20 20 20 20 Adhesive strength (kg / ㎡) Alloy 42 1.28 1.55 1.10 1.19 Copper 1.10 1.38 0.74 0.94 Hygroscopicity (wt%) 168 hours 0.32 0.27 0.36 0.35 Crack incidence Alloy 42 0/10 0/10 3/10 1/10 Copper 1/10 0/10 6/10 3/10

[Property evaluation method]

* Adhesive strength

: After the specimen was prepared and post-cured at 175 ° C. for 6 hours, the tensile force (UTM) between the alloy 42 and the copper lead frame and the epoxy encapsulant was evaluated.

* Moisture absorption and crack incidence

: 48 QFP was molded using alloy 42 and copper leadframe, post-cured at 175 ° C. for 6 hours, and then absorbed in boiling water for 168 hours and evaluated for moisture absorption. The absorbed 48 QFP was absorbed at 245 ° C. for 10 seconds. Package cracks were observed after three passes of IR reflow.

As can be seen from Table 1, the epoxy resin composition for sealing a semiconductor device of the present invention has a high adhesive strength with a lead frame, in particular, alloy 42, a low moisture absorption rate, and as a result, the crack generation rate is lowered.

As described in detail above, since the epoxy resin composition of the present invention has improved adhesion strength with a lead frame and excellent moisture resistance, sealing of a semiconductor device with the composition of the present invention can suppress crack generation.

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Claims (5)

(1) having two or more epoxy groups and having an epoxy equivalent of 100 to 220    Epoxy resin 3.5-10.0% by weight, (2) having two or more hydroxyl groups and having a hydroxyl equivalent weight of 100 to 200;    Hardener 2.0-10.0 wt%, (3) 0.1 to 0.5% by weight curing accelerator, (4) 80.0-91.0 weight% of inorganic fillers, and (5) Other additives 3.365-10.0 wt% In the epoxy resin composition for semiconductor element sealing comprising a, an epoxy resin composition for semiconductor element sealing comprising 0.035 to 3.0% by weight of the adhesion enhancer of the formula (1). [Formula 1] (Wherein R is an ethyl group or a methyl group and n is 0 to 3) The method of claim 1, The epoxy resin is an ortho cresol novolak resin, a biphenyl epoxy resin, a bisphenol A epoxy resin or a mixture thereof; The curing agent is a phenol novolak resin, xylok resin, dicyclopentadiene resin or mixtures thereof, and the content of xylox resin in the curing agent mixture is at least 40% by weight; The curing accelerator is a tertiary amine compound, imidazole compound, organic phosphine compound, tetraphenyl boron salt, or a mixture thereof. The method of claim 2, The epoxy resin mixture is epoxy resin composition for semiconductor element sealing, characterized in that the epoxy equivalent contains a biphenyl epoxy resin of 190 ~ 200 40% by weight or more. The method of claim 1, The inorganic filler is an epoxy resin composition for sealing a semiconductor device, characterized in that the average particle size is 0.1 ~ 35.0㎛, fused or synthetic silica having a composition ratio of the crushed and spherical is 7/3 ~ 0/10. The method of claim 1, The other additive is a flame retardant, flame retardant aid, release agent, colorant or coupling agent, characterized in that the epoxy resin composition for sealing semiconductor elements.