JP2000273156A - Semiconductor sealing epoxy resin molding material and semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a semiconductor sealing epoxy resin molding material excellent in curability and shelf stability and to provide a high moisture resistance semiconductor device using the same. SOLUTION: A semiconductor sealing epoxy resin molding material comprises, as the essential components, (A) a compound having two or more epoxy groups in the molecule, (B) a compound having two or more phenolic hydroxyl groups in the molecule, (C) a compound to be obtained by reacting (X) a compound containing at least one epoxy group in the molecule, (Y) an organic phosphine represented by the formula (wherein at least one of R1, R2 and R3 is selected from an alkyl group and an alkoxy group and the other groups are hydrogens and may be the same or different), and (Z) a compound (a proton donator compound) having a functional group capable of donating two or more protons in the molecule, and (D) an inorganic filler.

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 semiconductor encapsulation having excellent curability and preservability, and a semiconductor device using the same.

[0002]

2. Description of the Related Art Epoxy resin molding materials for semiconductor encapsulation are:
In order to accelerate the curing, a curing accelerator is blended and used. For example, in the case of an epoxy resin, amines, imidazole compounds, diazabicycloundecene (hereinafter, DB)
U), quaternary ammonium salts, organic phosphine compounds, phosphonium salts, and the like are often used as curing accelerators. Organic phosphines, especially triphenylphosphine (hereinafter, referred to as triphenylphosphine) , T
PP) is particularly commonly used.

However, when phosphines such as TPP are used, there have been problems in that the curing accelerator tends to be oxidized and deteriorated, and the storage stability of the epoxy resin molding material for semiconductor encapsulation at room temperature is low. As a method for solving these problems, Japanese Patent Application Laid-Open No. 7-252348 proposes the use of a heated mixture of a monoepoxy compound, a monovalent phenol compound, and an organic phosphine. Its presence has the disadvantage that it reduces the crosslink density of the molding material and reduces its curability.

On the other hand, JP-A-10-120765 discloses a tris-substituted organophosphine, an epoxy compound,
By preliminarily reacting a compound which is a proton donor forming an ion pair with a proton acceptor to form a quaternary phosphonium compound, the storage stability at room temperature is improved. However, there is no mention of the substituents of the tris-substituted organophosphine, and when the tris-substituted organophosphine is TPP, these quaternary compounds will react with triphenylphosphine oxide (hereinafter referred to as Tphenyl
PPO), and the curability may decrease.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in order to overcome the above-mentioned problems of the curing accelerator, and has been made as a result of various studies. It is an object of the present invention to provide a resin molding material and a highly moisture-resistant semiconductor device using the same.

[0006]

That is, the present invention provides a compound (A) having two or more epoxy groups in one molecule, a compound (B) having two or more phenolic hydroxyl groups in one molecule,
Compound (X) containing at least one epoxy group in one molecule, organic phosphine (Y) represented by the general formula (1), and a functional group capable of donating two or more protons in one molecule A compound (C) obtained by reacting a compound (proton donating compound, Z), and
An epoxy resin molding material for semiconductor encapsulation, comprising an inorganic filler (D) as an essential component, and a semiconductor device encapsulated with a cured product of the resin composition.

[0007]

Embedded image In the formula, at least one of R ¹ , R ² , and R ³ is a group selected from an alkyl group and an alkoxy group, and the other groups are hydrogen. Is also good.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Compound (A) used in the present invention
The resin is not particularly limited as long as it has two or more epoxy groups in one molecule, and a material generally used in an epoxy resin molding material for semiconductor encapsulation can be used. Specifically, phenolized novolak resins of phenols and aldehydes are epoxidized (eg, phenol novolak type epoxy resin, orthocresol novolak type epoxy resin), bisphenol A, bisphenol F, bisphenol S, bisphenol AD, alkyl-substituted biphenol And a glycidyl ether type epoxy resin formed by the reaction with epichlorohydrin.

Above all, a crystalline epoxy resin which has a rigid structure such as a biphenyl skeleton, a bisphenol skeleton, or a stilbene skeleton in its main chain and exhibits crystallinity due to its relatively low molecular weight is a solid crystallized at room temperature. However, in the temperature range above the melting point, it rapidly melts and changes into a low-viscosity liquid and has good fluidity, so that it is particularly useful for epoxy resin molding materials for semiconductor encapsulation. The melting point was measured using a differential scanning calorimeter at a temperature rising rate of 5 ° C. from room temperature.
It is determined as the temperature at the top of the endothermic peak of crystal melting when the temperature is raised at / min.

The crystalline epoxy resin satisfying these conditions is selected from the group consisting of a biphenyl type epoxy resin represented by the general formula (2) and a bisphenol type epoxy resin represented by the general formula (3). Preferred is a mixture of one or more of these, or a mixture of a stilbene-type epoxy resin represented by the general formula (4) and a stilbene-type epoxy resin represented by the general formula (5).

[0011]

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[0012]

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In the formula, R ⁴ and R ⁵ are groups or atoms selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen, and are the same as each other; May also be different, for example, a methyl group,
Ethyl group, propyl group, butyl group, cyclohexyl group,
Examples include a phenyl group, a chlorine atom and a bromine atom, and a methyl group is particularly preferable.

[0014]

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[0015]

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In the formula, R ^{6 to} R ¹⁷ are a hydrogen atom, a carbon atom of 1
~ 6 chain or cyclic alkyl groups, or groups or atoms selected from halogen, which may be the same or different, such as a hydrogen atom, a methyl group, an ethyl group, a propyl group, Butyl group, amyl group, hexyl group (including each isomer), cyclohexyl group, chlorine atom, bromine atom and the like. In particular, methyl group, ethyl group, propyl group, Or a butyl group is preferable.

The stilbene type epoxy resin of the general formula (4) and the stilbene type epoxy resin of the general formula (5) each have various structures depending on the kind of the substituent and the like.
A mixture of stilbene type epoxy resins of the general formula (4) and stilbene type epoxy resins of the general formula (5) may be used, although a mixture of two or more types may be used.

The mixing of the two resins is only required to lower the melting point by mixing both compounds, and the mixing method is not particularly limited. For example, stilbene-type phenols, which are the raw materials of the stilbene-type epoxy resin, are mixed before glycidyl etherification, or a method of melting and mixing both stilbene-type epoxy resins.In any case, Adjust so that the melting point is 50 to 150 ° C.

As the stilbene type epoxy resin represented by the general formula (4), from the viewpoint of availability, performance, and raw material price, 5
-Tert-butyl-4,4'-dihydroxy-2,3 ',
5'-trimethylstilbene, 3-tert-butyl-
Glycidyl etherified products of 4,4'-dihydroxy-3 ', 5,5'-trimethylstilbene are particularly preferred.

As the stilbene type epoxy resin represented by the general formula (5), 4,4′-dihydroxy-3,3 ′, 5,5′-tetramethylstilbene, 4,4 Glycidyl etherified products of '-dihydroxy-3,3'-ditert-butyl-6,6'-dimethylstilbene, 4,4'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethylstilbene are particularly preferred. preferable.

The compound (B) used in the present invention may be a compound in which two or more hydroxyl groups are bonded to an aromatic ring in one molecule, and may be a phenol novolak resin, a cresol novolak resin, a phenol aralkyl resin, Examples include terpene-modified phenolic resins, dicyclopentadiene-modified phenolic resins, and the like.However, since the number of hydroxyl groups in the molecule is small, the water absorption of the molded product is small, and the reactivity in the curing reaction is low because the molecule has an appropriate flexibility. Phenol aralkyl resins are particularly preferred because they are good and can be reduced in viscosity.

The compound (C) used in the present invention
Is a compound which acts as a latent curing accelerator, and as a compound (X) containing at least one epoxy group in one molecule for synthesizing the compound (C),
In addition to the compound (A) having two or more epoxy groups in the molecule, a monofunctional epoxy compound can also be used. Although it does not specifically limit as a monofunctional epoxy compound, For example, phenyl glycidyl ether, tertiary butyl glycidyl ether, allyl glycidyl ether etc. are mentioned.

The organic phosphine (Y) represented by the general formula (1) for synthesizing the compound (C) has a substituent R ¹
At least one of R ³ is an alkyl group or an alkoxy group, but the other groups are hydrogen atoms,
They may be the same or different. Specifically, tris (4-methylphenyl) phosphine, tris (2,4,
6-trimethylphenyl) phosphine, tris (2,6
-Dimethoxyphenyl) phosphine, tris (2,4,6)
-Trimethoxyphenyl) phosphine and the like. The generated phosphonium salt is stabilized by these electron donating groups, and the oxidation and decomposition reactions during the curing reaction are suppressed. In the case of TPP in which all of the substituents R ^{1 to} R ³ are hydrogen atoms, the stability of the phosphonium salt itself is relatively low, and phosphine oxide is easily formed at high temperatures, so that the curability tends to decrease.

The proton donating compound (Z) used for the synthesis of the compound (C) has a functional group capable of donating one proton.
It is important to have two or more in the molecule. For example, when a monovalent phenol compound having one proton donating group is used, since the monofunctional phenol compound is used, in the reaction at the time of curing the phenol compound and the epoxy group, the curability is lowered by reducing the crosslink density. descend. Therefore, the compound must have two or more proton donating groups in one molecule. Specifically, catechol, resorcin, dihydroxybenzenes such as hydroquinone, dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene,
Bisphenols such as bisphenol A and bisphenol F, biphenols such as 2,2'-biphenol, 3,3 ', 5,5'-tetramethyl-4,4'-biphenol, and phenol resins such as phenol novolak and cresol novolak Phenolic hydroxyl group-containing compounds such as phenol aralkyl resins, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, compounds having a carboxyl group such as polyacrylic acid, salicylic acid, compounds having a phenolic hydroxyl group and a carboxyl group such as hydroxynaphthoic acid, Polyhydric alcohols such as 1,5-pentanediol are exemplified. In the present invention, the organic phosphine nucleophilically attacks and opens the epoxy group, and the generated alcoholate anion is a strong base.Even when an alcohol that is a weak proton donor is used, a curing accelerator for a thermosetting resin is used. Compound (C) is obtained.

The compound (C) in the present invention can be prepared as follows. First, an aprotic polar solvent, for example, acetone, tetrahydrofuran (hereinafter, referred to as
The compound (X) and the organic phosphine (Y) are dissolved in, for example, THF, and the mixture is heated and stirred. Next, the proton donating compound (Z) is dissolved in the above-mentioned solvent and added dropwise to this solution. After the completion of the dropwise addition, the reaction was continued for a while.
(Thin layer chromatography) to confirm that the raw material compounds have been completely consumed. Thereafter, the pressure inside the reaction vessel is reduced to remove the solvent to the outside of the reaction vessel to obtain the desired compound (C).

The type of the inorganic filler (D) used in the present invention is not particularly limited, and those generally used for epoxy resin molding materials can be used.
For example, fused crushed silica powder, fused spherical silica powder, crystalline silica powder, secondary agglomerated silica powder, alumina, titanium white, aluminum hydroxide, talc, clay, glass fiber, etc., are preferred, and fused spherical silica powder is particularly preferred. The shape is preferably infinitely spherical, and
By mixing particles having different particle sizes, the filling amount can be increased.

The compounding amount of the inorganic filler is a total amount of the compound (A) having two or more epoxy groups in one molecule and the compound (B) having two or more phenolic hydroxyl groups in one molecule. 200 to 2400 per part by weight
Parts by weight are preferred. If it is less than 200 parts by weight, the reinforcing effect of the inorganic filler may not be sufficiently exhibited, and if it is more than 2400 parts by weight, the fluidity of the resin composition may be reduced and poor filling may occur during molding. Is not preferred. In particular, the compounding amount of the inorganic filler is 2 per 100 parts by weight of the total amount of the compound (A) and the compound (B).
When the amount is 50 to 1400 parts by weight, the moisture absorption of the cured product of the resin composition becomes low, and the occurrence of solder cracks can be prevented. Further, the viscosity of the resin composition at the time of melting becomes low. This is more preferable since there is no possibility of causing gold wire deformation. It is preferable that the inorganic filler is sufficiently mixed in advance.

The epoxy resin molding material for encapsulating a semiconductor of the present invention comprises, in addition to the components (A) to (D), if necessary, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, carbon black and the like. Colorants, flame retardants such as brominated epoxy resins, antimony oxide, and phosphorus compounds; low-stress components such as silicone oil and silicone rubber; release agents such as natural waxes, synthetic waxes, higher fatty acids and their metal salts, and paraffin. And various additives such as antioxidants, and triphenylphosphine, 1,8-, as long as the properties of the latent catalyst of the present invention are not impaired.
There is no problem when used in combination with other known catalysts such as diazabicyclo (5,4,0) undecene-7 and 2-methylimidazole.

The epoxy resin molding material for semiconductor encapsulation of the present invention comprises the components (A) to (D), and other additives.
It is obtained by mixing at room temperature using a mixer, kneading with a kneading machine such as a roll or an extruder, cooling and pulverizing.

The semiconductor device sealed with the cured product of the epoxy resin molding material of the present invention is included in the technical scope of the present invention and exhibits excellent moisture resistance.

[0031]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited thereto. Here, first, a compound (C) serving as a latent curing accelerator is synthesized, and then an epoxy resin composition (molding material) containing the obtained compound (C) is prepared, and its properties are evaluated. Therefore, the spiral flow, the curing torque, and the residual flow rate were measured, and the humidity resistance reliability test was performed. The measuring method and conditions of each characteristic were as follows.

1. Spiral flow For the resin composition immediately after preparation, EMMI-I-
Using a mold for spiral flow measurement according to No. 66, the mold temperature was 175 ° C., the injection pressure was 70 kg / cm ² , and the curing time was 2 minutes. Spiral flow (cm) is a parameter of fluidity, and the larger the numerical value, the better the fluidity.

2. Curing Torque Using the prepared resin composition, a curast meter (JSR Curast Meter PS manufactured by Orientec Co., Ltd.)
), And the torque after heating at 175 ° C. for 45 seconds was determined. Torque value in curast meter (kgf · c
m) is a curability parameter, and a larger value indicates higher curability.

3. After storing at 30 ° C. for 1 week, the spiral flow was measured, and the percentage of the spiral flow immediately after the preparation (%)
Ask for. The larger the value, the better the preservability.

4. Moisture resistance reliability Using the prepared resin composition, a mold temperature of 175 ° C., a pressure of 70 kg / cm ² , and a curing time of 2 minutes were used to obtain 16 pDI.
After molding P (monitor IC with simulated element),
Post-curing was performed at 175 ° C. for 8 hours to prepare a sample device. A voltage of 20 V was applied to this element in water vapor at 125 ° C. and a relative humidity of 100%, and the time until a disconnection failure occurred was examined. Until a failure occurred in eight or more of the 15 sample elements. Time was taken as bad time. Note that the measurement time was 500 hours at the maximum, and when the number of defective samples was less than 8 at that time, the defective time was 50 hours.
Displayed as 0 hours or more. The longer the failure time, the better the moisture resistance reliability.

(Synthesis Example 1) 1.51 parts of phenylglycidyl ether and 3.04 parts of tris (4-methylphenyl) phosphine were placed in a glass reaction vessel, and dissolved in 100 parts of acetone. In addition, bisphenol FD
A solution prepared by dissolving 1.00 part (produced by Honshu Chemical Industry Co., Ltd.) in 50 parts of acetone was heated at an oil bath temperature of 80 ° C.
While stirring and refluxing, the mixture was dropped and reacted over about 5 hours. Thereafter, the pressure inside the reaction vessel was reduced to 2 to 3 mmHg for 30 minutes, and the solvent was removed outside the reaction vessel to obtain the target compound. This is designated as Compound 1.

(Synthesis Examples 2 to 13) In the same manner as in Synthesis Example 1, Compounds 2 to 13 were synthesized. Details of the used starting compounds and the like are shown in Tables 1 and 2.

[0038]

[Table 1]

[0039]

[Table 2]

Example 1 According to the following formulation, each component was first mixed at room temperature, then kneaded at 95 ° C. for 8 minutes using a hot roll, cooled and pulverized to obtain an epoxy resin molding material. The obtained molding material was subjected to evaluation of each property, and the evaluation results were as shown in Table 3.

51 parts by weight of a resin containing a biphenyl epoxy resin represented by the formula (6) as a main component (epoxy equivalent: 185, melting point: 105 ° C.) 51 parts by weight: a phenol aralkyl resin represented by the formula (7): (Point 73 ° C) 49 parts by weight Compound 1 1.7 parts by weight Fused spherical silica 500 parts by weight Carbon black 2 parts by weight Brominated bisphenol A type epoxy resin 2 parts by weight Carnauba wax 2 parts by weight

[0042]

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[0043]

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(Examples 2 to 14, and Comparative Examples 1 to 5)
Compound 1 in Example 1 was replaced with Compound 2 to Compound 13,
An epoxy resin molding material was prepared and evaluated in the same procedure as in Example 1 except for changing the above. Details of the used starting compounds and the evaluation results are summarized in Tables 3 and 4. The crystalline epoxy resin A used in Example 2 is a resin 60 containing 4,4′-bis (2,3-epoxypropoxy) -3,3 ′, 5,5′-tetramethylstilbene as a main component. Weight% and 4,4′-bis (2,
3-epoxypropoxy) -5-tert-butyl-
40% by weight of a resin containing 2,3 ′, 5′-trimethylstilbene as a main component (melting point: 120 ° C., epoxy equivalent: 209).

[0045]

[Table 3]

[0046]

[Table 4]

As can be seen from the evaluation results shown in Tables 3 and 4, in each of the examples, the curability, the preservability, and the moisture resistance reliability were all good, and in particular, the flow residual rates were all high. On the other hand, in the comparative example, curability and preservability were not compatible, and a satisfactory product was not obtained.

[0048]

According to the present invention, the compound (X) containing at least one epoxy group in one molecule, the organic phosphine (Y) represented by the general formula (1), and the proton donating compound (Z) are obtained by reaction. The epoxy resin molding compound for semiconductor encapsulation using the compound as a latent curing accelerator has excellent curability and storability, and the semiconductor device encapsulated using the cured product of this molding material has high moisture resistance. Excellent in reliability
The benefits to the electric and electronic industries are great and useful.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/31 (72) Inventor Akiko Okubo 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. (72) Inventor Hitto Akiyama 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. F-term (reference) 4J002 BG01Y CC04X CC04Y CC05X CC05Y CD05W CD06W CE00X CE00Y DE137 DE147 DJ017 DJ037 DJ047 DL007 EC046 EF116 EJ016 EJ026 EJ066 FA047 FA087 FD017 FD090 FD130 FD156 FD160 GQ05 4J036 AD07 AD08 AD10 AF06 AF07 AF08 DB05 DB06 DB12 DB22 DB25 DC41 DC46 DD07 FA03 FA05 FB07 FB08 4M109 AA01 BA01 CA21 EA03 EA06 EB03 EB03 EB03 EB03 EB03 EB03 EB04

Claims (6)

[Claims] 1. A compound having two or more epoxy groups in one molecule (A), a compound having two or more phenolic hydroxyl groups in one molecule (B), and containing at least one epoxy group in one molecule (X), an organic phosphine (Y) represented by the general formula (1), and a compound having a functional group capable of donating two or more protons in one molecule (proton donating compound, Z). An epoxy resin molding material for encapsulating a semiconductor, characterized by comprising, as essential components, a compound (C) obtained by the method described above and an inorganic filler (D). Embedded image In the formula, at least one of R ¹ , R ² , and R ³ is a group selected from an alkyl group and an alkoxy group, and the other groups are hydrogen. Is also good. 2. The compound (A) is one or more selected from the group consisting of a biphenyl type epoxy resin represented by the general formula (2) and a bisphenol type epoxy resin represented by the general formula (3). The epoxy resin molding material for semiconductor encapsulation according to claim 1, characterized in that it is a mixture of: Embedded image Embedded image In the formula, R ⁴ and R ⁵ are a group or an atom selected from hydrogen, a chain or cyclic alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen. You may. 3. The compound (A) is a mixture of a stilbene type epoxy resin represented by the general formula (4) and a stilbene type epoxy resin represented by the general formula (5). 2. The epoxy resin molding material for semiconductor encapsulation according to 1. Embedded image Embedded image In the formula, R ^{6 to} R ¹⁷ are a hydrogen atom, a chain or cyclic alkyl group having 1 to 6 carbon atoms, or a group or atom selected from halogen, and may be the same or different. Good. 4. The epoxy resin molding material for semiconductor encapsulation according to claim 1, wherein the compound (B) is a phenol aralkyl resin. 5. The proton-donating compound (Z) is a compound having two or more functional groups in one molecule selected from the group consisting of an alcoholic hydroxyl group, a phenolic hydroxyl group, and a carboxyl group. An epoxy resin molding material for semiconductor encapsulation according to claim 1. 6. A semiconductor device encapsulated with a cured product of the epoxy resin molding material for semiconductor encapsulation according to any one of claims 1 to 5.