JPH11158351A - Epoxy resin composition and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having excellent storage property at a high temperature and excellent resistance to cracking induced by soldering and useful for sealing a semiconductor by using a crystalline epoxy resin, a specific phenolic resin hardener and a zeolite having a specific structure. SOLUTION: This epoxy resin composition comprises (A) a crystalline epoxy resin having 50-150 deg.C melting point, (B) a phenolic resin hardener containing >=50 wt.% of a phenolic resin (e.g. biphenyl type) selected from formulae I and II R1 is formula III or IV; R2 is formula III, (m) is 1-10}, (C) a hardening accelerator (e.g. triphenylphosphine, (D) an inorganic filler (preferably a spherical silica powder having extremely true sphere shape and a broad granular size distribution) in an amount of 75-92 wt.% based on the weight of the whole composition and (E) a compound of the formula: XM2/n O.Al2 O3 .YSiO2 .ZH2 O X=0.1-2; Y=1-200; Z=0-100; M is an alkaline (earth) metal; (n) is atomic valence} as essential components. Preferably, a maximum granular diameter of the component E is 150 μm and an average granular diameter of the same is 5-30 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for semiconductor encapsulation having excellent high-temperature storage characteristics and good solder crack resistance, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Epoxy resin compositions have been developed and manufactured to protect semiconductors from mechanical and chemical actions. Items required for the resin composition vary depending on the structure of the semiconductor device to be sealed. As a property required for a sealing material with the surface mounting of a semiconductor package, there is solder crack resistance. In order to improve the solder crack resistance, for example, a method of using a crystalline biphenyl type epoxy resin and highly filling silica as an inorganic filler is used. Further, due to the heat generation of the semiconductor element due to the increase in the speed and the use in a severe environment such as a vehicle-mounted component, it is required to improve the high-temperature storage characteristics as well as the solder crack resistance.

[0003] However, the epoxy resin composition is also required to be flame-retardant, and usually a bromine compound and antimony oxide are blended for imparting flame retardancy. However,
It is known that thermally decomposed bromine compounds are liberated from these flame-retardant components, thereby impairing the reliability of the junctions of semiconductor elements. The term “reliability” as used herein refers to a junction (bonding pad portion) of a semiconductor element obtained by leaving a semiconductor device obtained by sealing a semiconductor element using the epoxy resin composition at a high temperature (for example, 185 ° C.). (Hereinafter referred to as high-temperature storage characteristics). As a method for improving the high-temperature storage characteristics, a method of blending diantimony pentoxide (JP-A-61-53321) or a method of combining antimony oxide with an organic phosphine (JP-A-61-53).
321) has been proposed, but at present it has not yet reached the required level of reliability of semiconductor devices.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a crystalline epoxy resin, one or more phenols selected from the group of formulas (1) and (2). An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation having excellent high-temperature storage characteristics and good solder crack resistance by using a resin and a compound of the formula (3), and a semiconductor device using the same.

[0005]

According to the present invention, (A) a melting point of 5
A crystalline epoxy resin at 0 to 150 ° C., (B) a resin curing agent containing 50% by weight or more of one or more phenolic resins selected from the group of formulas (1) and (2) in the total phenolic resin curing agent, C) a curing accelerator, (D) 75 in the total resin composition
An epoxy resin composition for semiconductor encapsulation comprising, as essential components, an inorganic filler containing up to 92% by weight and (E) a compound of the formula (3).

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[0006]

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XM _{2 / n} O.Al ₂ O ₃ .YSiO ₂ .ZH ₂ O (3) (where X = 0.1 to 2.0, Y = 1.0 to 200,
Z = 0 to 100, M is an alkali metal or an alkaline earth metal, and n is its valence. )

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The epoxy resin used in the present invention is a crystalline epoxy resin having a melting point of 50 to 150 ° C.
Crystalline epoxy resin has a low molecular weight and planar structure skeleton in molecular structure.It is a solid that crystallizes at room temperature, but it rapidly melts in the temperature range above its melting point when the temperature rises. And low viscosity (about 0.1-10 poise / 150-175
(° C). The melting point of the crystalline epoxy resin referred to in the present invention is defined by a differential scanning calorimeter at a heating rate
It is a melting peak measured at ° C./min. Melting point is 50
If it is lower than 50 ° C., it melts at room temperature, and there is a possibility that workability may be deteriorated and the room temperature storage property of the epoxy resin composition may be lowered. If the temperature exceeds 150 ° C., it does not melt sufficiently during kneading and cannot be uniformly dispersed, so that the curability is reduced and the moldability is reduced. Further, a nonuniform molded product is obtained. I do.

Epoxy resins satisfying these conditions include, for example, biphenyl type, hydroquinone type, stilbene type, bisphenol F type, and naphthalene type, and these may be used alone or as a mixture. In order to improve the moisture resistance reliability, it is desirable that chlorine ions, sodium ions and other free ions contained in these epoxy resins are as small as possible. The epoxy equivalent is 10
0 to 350 is preferred. If it is less than 100, the number of reaction points increases, so that the water absorption of the cured product of the resin composition increases, and the solder crack resistance decreases. When it exceeds 350,
Reactivity decreases and moldability deteriorates. Specific examples of the structure of the crystalline epoxy resin include, but are not limited to, the following.

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[0010]

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[0011]

Embedded image In addition, other epoxy resins, such as an ortho-cresol novolak-type epoxy resin, a dicyclopentadiene-modified epoxy resin, a heterocyclic epoxy resin, etc., within a range that does not impair the high filling of the inorganic filler which is a characteristic of the crystalline epoxy resin. You may use together.

Formulas (1) and (2) used in the present invention
Of phenolic resin in all phenolic resin curing agents
What is necessary is just to contain by weight% or more. Equation (1) and Equation (2)
The phenol resin significantly reduces the water absorption of the cured product of the resin composition as compared with the conventional phenol novolak resin, and thus improves the solder crack resistance of the cured product. 50
When the amount is less than the weight percentage, the water absorption of the cured product of the resin composition increases, and the solder crack resistance of the cured product is undesirably reduced. The value of m is preferably 1 to 10. If m exceeds 10, the viscosity increases and the fluidity of the resin composition decreases, which is not preferable. Further, in order to improve the moisture resistance reliability, it is desirable that chlorine ions, sodium ions, and other free ions contained as impurities be as small as possible. Furthermore, examples of other phenol resins that can be used in combination with the phenol resins of the formulas (1) and (2) include polyphenol compounds such as a phenol novolak resin, a cresol novolak resin, a dicyclopentadiene-modified phenol resin, and a polyvinyl phenol resin. However, the present invention is not limited to these.

The curing accelerator used in the present invention is not particularly limited as long as it promotes a chemical reaction between an epoxy group and a phenolic hydroxyl group. Generally, triphenylphosphine, 1,8-
Diazabicyclo (5,4,0) undecene-7, tetraphenylphosphonium tetraborate salt, 2-methylimidazole and the like. In order to improve the moisture resistance of the resin composition, it is desirable that ionic impurities be as low as possible.
Further, a curing accelerator having a latent catalytic action is more preferable.

The inorganic filler used in the present invention includes:
Fused silica powder, spherical silica powder, crystalline silica powder, 2
Sub-agglomerated silica powder, alumina and the like are mentioned, and spherical silica powder is particularly desirable from the viewpoint of improving the fluidity of the epoxy resin composition. As the shape of the spherical silica powder, it is desirable that the shape of the particles themselves is infinitely spherical and the particle size distribution is broad in order to improve fluidity. Further, in order to improve moisture resistance, it is desired that ionic impurities such as alkali metals, alkaline earth metals, and halogens are contained as little as possible. The blending amount of the inorganic filler is preferably from 75 to 92% by weight based on the entire epoxy resin composition. If it is less than 75% by weight, the water absorption of the cured product of the resin composition will increase, and the solder crack resistance will decrease. If the content exceeds 92% by weight, the melt viscosity of the resin composition becomes too high even when spherical silica is used, and molding cannot be performed. The inorganic filler is an unsaturated double bond-containing silane coupling agent and other silane-based, titanium-based,
There is no problem even if the surface is previously treated with another surface treating agent.

The compound of the formula (3) used in the present invention is
Generally called zeolite, has a crystal structure,
There are countless vacancies having a diameter of 3 to 20 angstroms in the crystal grains, which have a function of adsorbing and holding substances such as water, ammonia, and carbon dioxide. The inventor has proposed a crystalline epoxy resin,
As a result of earnestly studying a resin composition containing the phenolic resin of the formula (1) and the formula (2) and the compound of the formula (3),
It has been found that a semiconductor device sealed with this resin composition has excellent high-temperature storage characteristics and solder crack resistance. The maximum particle size of the compound of the formula (3) is 200 μm
Hereinafter, it is more preferably 150 μm. If it exceeds 200 μm, it is not preferable because it causes unfilling during molding. The average particle size is not particularly limited.
The range of m is preferred. The compounding amount in the whole resin composition is 0.1 to 10% by weight, more preferably 0.1 to 5% by weight. If it is less than 0.1% by weight, the adsorption performance is low and sufficient high-temperature storage characteristics cannot be obtained. If it exceeds 10% by weight, the water absorption of the cured product of the resin composition increases, and the solder crack resistance decreases. The shape of the particles may be crushed or spherical, but is not particularly limited.

The resin composition of the present invention comprises, in addition to the components (A) to (E), if necessary, a coloring agent such as carbon black, a release agent such as natural wax and synthetic wax, and a silicone oil, rubber and the like. Flame retardants such as low stress components, antimony oxide and bromine compounds can be added. The resin composition of the present invention is obtained by mixing the components (A) to (E) and other additives at room temperature with a mixer, kneading with a general kneading machine such as a roll or an extruder, cooling, and pulverizing. In order to manufacture a semiconductor device by encapsulating an electronic component such as a semiconductor using the resin composition of the present invention, it is only necessary to cure and mold by a conventional molding method such as transfer molding, compression molding and injection molding.

[0017]

The present invention will be specifically described below with reference to examples.
The mixing unit is parts by weight. Example 1 5.10 parts by weight of epoxy resin 1 (manufactured by Yuka Shell Epoxy Co., Ltd., YX4000, melting point 105 ° C., epoxy equivalent: 195) 5.10 parts by weight Phenol resin 1 (manufactured by Mitsui Chemicals, Inc., XL-225-LL, Softening point 100 ° C, hydroxyl equivalent 175) 5.10 parts by weight 1,8-diazabicyclo (5,4,0) undecene-7 (hereinafter referred to as DBU) 0.2 part by weight Spherical silica (average particle diameter 15 μm) 0 parts by weight Compound of formula (3) (average particle diameter 6 μm, maximum particle diameter 40 μm) 2.0 parts by weight Carbon black 0.3 parts by weight Carnauba wax 0.3 parts by weight Antimony trioxide 1.0 part by weight Brominated phenol 1.0 part by weight of novolak type epoxy resin was mixed at room temperature with a mixer, kneaded at 100 ° C. using a biaxial roll, cooled, and ground to obtain a resin composition. The obtained resin composition was evaluated by the following method. Table 1 shows the results.

Evaluation method Spiral flow: Spiral flow was measured using a mold for measuring spiral flow according to EMMI-I-66 at a mold temperature of 175 ° C., an injection pressure of 70 kg / cm ² , and a curing time of 2 minutes. The unit is cm. High-temperature storage characteristics: The resin composition was molded using a transfer molding machine at a molding temperature of 175 ° C., a pressure of 70 kg / cm ² ,
A 16 pDIP was molded with a curing time of 2 minutes and post-cured at 175 ° C. for 8 hours. 185 of these packages
Leave in an atmosphere of ℃, measure the circuit resistance of the simulated element,
The point at which the measured value increased by 20% or more from the initial value was determined to be defective, and was taken as the circuit resistance defective rate during high-temperature storage. The time when the number of defects reaches 50% of the total number of packages is defined as the defect time.
Those with a time of 00 hours or more were accepted. Solder crack resistance: The above resin composition was molded using a transfer molding machine at a molding temperature of 175 ° C. and a pressure of 70 kg / cm.
^2. Form 80pQFP (thickness 2mm, element size 9mm x 9mm) with curing time of 2 minutes, post cure 175
C. for 8 hours. After six packages were absorbed for 168 hours in an atmosphere of 85 ° C. and 85% relative humidity, IR reflow treatment (240 ° C., 10 seconds) was performed. After the treatment, external cracks were observed with a microscope. When the number of cracked packages was n, it was indicated as n / 6.

Examples 2 to 7 Compounded according to the formulation shown in Table 1, a resin composition was obtained in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. Comparative Examples 1 to 4 Resins were blended in accordance with the formulation shown in Table 1 to obtain a resin composition in the same manner as in Example 1, and evaluated in the same manner as in Example 1. Table 1 shows the results. The materials used in the examples and comparative examples are shown below. The epoxy resin 2 is composed of 60% by weight of a resin containing 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylstilbene as a main component and 4,4'-bis It is a mixture of (2,3-epoxypropoxy) -5-tert-butyl-2,3 ', 5'-trimethylstilbene and a resin having a main component of 40% by weight (melting point: 130 ° C., epoxy equivalent: 210). Phenol resin 2 (Formula (4), hydroxyl equivalent 105)

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Phenol resin 3 (formula (5), hydroxyl equivalent 210)

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[0021]

[Table 1]

[0022]

The semiconductor device sealed with the resin composition of the present invention is excellent in high-temperature storage characteristics and solder crack resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/31

Claims (2)

[Claims] 1. One or more phenolic resins selected from the group of formulas (1) and (2) are added to (A) a crystalline epoxy resin having a melting point of 50 to 150 ° C. and (B) a total phenolic resin curing agent. (C) a curing accelerator containing not less than 75% by weight, (D) an inorganic filler containing 75 to 92% by weight in the total resin composition, and (E) a compound of the formula (3) as essential components. An epoxy resin composition for semiconductor encapsulation characterized by the following. Embedded image Embedded image _{XM 2 / n O · Al 2} O 3 · YSiO 2 · ZH 2 O (3) ( where, X = 0.1~2.0, Y = 1.0~200 ,
Z = 0 to 100, M is an alkali metal or an alkaline earth metal, and n is its valence. ) 2. A semiconductor device sealed with the epoxy resin composition according to claim 1.