JPH1060091A - Epoxy resin composition for sealing semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of providing a cured material excellent in heat resistance, low hydroscopic properties and low stress and manifesting solder crack resistance by formulating an epoxy resin containing a spirochroman skeleton with a specific resin curing agent, etc. SOLUTION: This composition is obtained by formulating an epoxy resin of the formula (R1 to R4 are each H or a 1-6C hydrocarbon; R5 to R10 are each R1 or a halogen; (n) is 0-5), (B) a curing agent for a (modified) phenolic epoxy resin such as a phenol novolak resin, (C) a curing promoter and (D) an inorganic filler as essential components. Preferably, the amount of the component B is an amount to give 0.5-2mol of the epoxy reactive group in the component B based on 1mol epoxy in the component A and that of the component C is 0.1-5 pts.wt. based on 100 pts.wt. of the component A. A ground type or spherical fused silica is formulating as the component D and its amount is 60-95wt.% based on the whole amount of the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an epoxy resin composition for encapsulating a semiconductor. Specifically, the present invention relates to a cured product obtained by blending a spirochroman skeleton-containing epoxy resin with a specific epoxy resin curing agent, a curing accelerator and an inorganic filler, having high heat resistance, and excellent in low moisture absorption and low stress. And a novel epoxy resin composition for encapsulating a semiconductor.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices have become more highly integrated,
Various characteristics required for a sealing material for a semiconductor element have become severe, and crack resistance during immersion in a solder bath has become an important issue. However, epoxy resin compositions generally used at present have not been able to sufficiently satisfy required characteristics. In other words, the integration of the semiconductor device has been advanced, and the size of the semiconductor element has been significantly increased, and the package itself has been reduced in size and thickness. In addition, the mounting of semiconductor devices has also shifted to surface mounting. In surface mounting, a semiconductor device is directly immersed in a solder bath and is exposed to a high temperature, so that a high glass transition temperature is required. If the internal stress is high, a shift in aluminum wiring and a crack in passivation are caused. Also, when exposed to the high temperature, due to the expansion of the absorbed moisture, a large stress is applied to the entire package,
Cracks are formed in the sealing material. Therefore, a sealing material with good solder crack resistance is required to have high heat resistance, excellent low moisture absorption, and excellent low stress, and the cresol novolac type epoxy resin which is mainly used at present is used. Epoxy resin encapsulants comprising a phenol novolak resin curing agent have become insufficient in heat resistance, low hygroscopicity and low stress.

For this reason, for example, Japanese Patent Application Laid-Open No. 61-4772
JP-A-5-14141 proposes a tetramethylbiphenol-type epoxy resin having low stress, low moisture absorption, and excellent solder cracking resistance.
No. 9 proposes an epoxy resin having a high glass transition temperature and derived from a condensate of a phenol and a hydroxybenzaldehyde.

[0004]

However, the former cannot be said to have a sufficient glass transition temperature, and the latter has a high glass transition temperature, but has a large stress and a low hygroscopic property. Is not improved. An object of the present invention is to provide an epoxy resin composition for semiconductor encapsulation that has high heat resistance, and is capable of giving a cured product excellent in low hygroscopicity and low stress, and has excellent solder crack resistance. It is in.

[0005]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have found that an epoxy resin having a spirochroman skeleton is mixed with a specific epoxy resin curing agent or the like. The resin composition has heat resistance,
It has been found that the composition provides excellent curability with low moisture absorption and low stress, and the present invention has been completed.

That is, the present invention provides: (A) a spirochroman skeleton-containing epoxy resin represented by the following general formula (I), (b) a phenolic and / or modified phenolic epoxy resin curing agent, (c) a curing accelerator, and (d) an inorganic filler. Epoxy resin composition for semiconductor encapsulation formulated as an essential component,

[0007]

Embedded image

(Where R₁, R_Two, R_ThreeAnd R_FourIs the water
Represents an atomic atom or a hydrocarbon group having 1 to 6 carbon atoms,
They may be the same or different. R_Five, R₆, R₇, R
₈, R ₉And R_TenIs a hydrogen atom, a halogen atom or carbon
Represents a hydrocarbon group of the formulas 1 to 6, each being the same or different
It may be. N is an average number from 0 to 5
1. (A) Spirochrome represented by the general formula (I)
The epoxy resin containing a man skeleton is represented by the following general formula (II)
Is a spirochroman skeleton-containing epoxy resin
The epoxy resin composition described,

[0009]

Embedded image

Wherein R ′ ₁ , R ′ ₂ , R ′ ₃ and R ′
₄ represents a methyl group. _{R '5, R' 6,} R '7,
R _'8, R' ₉ and R _'10 represents a hydrogen atom or a methyl group, may each be the same or different. Also,
n 'is a number from 0 to 5 on average) Component (a) is composed of a spirochroman skeleton-containing epoxy resin represented by the general formula (I): 50 to 100% by weight, and an epoxy resin having another structure: 0 to 50% by weight.
Or the epoxy resin composition according to item 2, The epoxy according to any one of claims 1 to 3, wherein at least one selected from the group consisting of a phenol novolak resin, a phenol aralkyl resin, a dicyclopentadiene phenol resin and a terpene phenol resin is blended as an essential component as the component (b). 4. a resin composition; Item 1 to Item 4 wherein the component (b) is used so that the amount of the group that reacts with the epoxy group in the component (b) is 0.5 to 2.0 mol per 1 mol of the epoxy group in the component (a). 5. The epoxy resin composition according to any of the above, The component (c) is added in an amount of 0.1 to 100 parts by weight of the component (a).
6. The epoxy resin composition according to any one of Items 1 to 5, which is blended in an amount of 1 to 5.0 parts by weight. (D) As a component, 60 to 95% by weight of the total amount of the composition
7. The epoxy resin composition according to any one of claims 1 to 6, wherein a crushed and / or spherical, fused and / or crystalline silica powder filler is used. Hereinafter, the present invention will be described in detail.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The spirochroman skeleton-containing epoxy resin represented by the general formula (I), preferably (II), used in the present invention is a phenol represented by the following general formula (III), preferably (IV) It is produced by subjecting a compound and epihalohydrin to a condensation reaction in the presence of an alkali.

[0012]

Embedded image

(Wherein R₁₁, R₁₂, R₁₃And R₁₄Is the water
Represents an atomic atom or a hydrocarbon group having 1 to 6 carbon atoms,
They may be the same or different. R_Fifteen, R₁₆, R₁₇, R
₁₈, R ₁₉And R₂₀Is a hydrogen atom, a halogen atom or carbon
Represents a hydrocarbon group of the formulas 1 to 6, each being the same or different
May be

[0014]

Embedded image

(Wherein R ′ ₁₁ , R ′ ₁₂ , R ′ ₁₃ and R ′
₁₄ represents a methyl group. _{R '15, R' 16,} R '17,
R _'18, R' ₁₉ and R _'20 represents a hydrogen atom or a methyl group, may each be the same or different. This reaction can be carried out in the same manner as a usual epoxidation reaction. A typical production example of the reaction is described in detail below.
First, a phenol compound represented by the above general formula (III), preferably (IV), is dissolved in an amount of epihalohydrin corresponding to 2 to 20 mol per mol of the phenolic hydroxyl group to form a uniform solution. Then, while stirring the solution, 1-2 moles of an alkali metal hydroxide per 1 mole of a phenolic hydroxyl group is added as a solid or an aqueous solution and reacted. This reaction can be carried out under normal pressure or reduced pressure, and the reaction temperature is usually about 3 when the reaction is carried out under normal pressure.
0 to 105 ° C. and about 30 to 8 in the case of a reaction under reduced pressure.
0 ° C. During the reaction, the reaction solution is azeotroped while maintaining a predetermined temperature as needed, and the condensate obtained by cooling the volatilizing vapor is separated into oil / water, and the oil component from which water has been removed is fed to the reaction system. It is dehydrated from the reaction system by the returning method. The addition of the alkali metal hydroxide suppresses the rapid reaction,
Add in small portions intermittently or continuously over 0.5-8 hours. The total reaction time is usually about 1 to 10 hours. After completion of the reaction, insoluble by-product salts are removed by filtration or removed by washing with water, and unreacted epihalohydrin is removed by distillation under reduced pressure to obtain the desired epoxy resin. In this reaction, epichlorohydrin or epibromohydrin is usually used as epihalohydrin, and caustic soda or potassium hydroxide is usually used as alkali metal hydroxide.

In this reaction, quaternary ammonium salts such as tetramethylammonium chloride and tetraethylammonium bromide; tertiary amines such as benzyldimethylamine and 2,4,6- (trisdimethylaminomethyl) phenol; Catalysts such as imidazoles such as 2-ethyl-4-methylimidazole and 2-phenylimidazole; phosphonium salts such as ethyltriphenylphosphonium iodide; and phosphines such as triphenylphosphine may be used.

Further, in this reaction, ethanol,
Alcohols such as isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and ethylene glycol dimethyl ether; and inert organic solvents such as aprotic polar solvents such as dimethyl sulfoxide and dimethylformamide may be used. Further, when the amount of the saponified halogen in the epoxy resin obtained as described above is too large, the epoxy resin can be re-processed to obtain a purified epoxy resin in which the amount of the saponified halogen is sufficiently reduced. That is, the epoxy resin composition is redissolved in an inert organic solvent such as isopropanol, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, dioxane, propylene glycol monomethyl ether, dimethyl sulfoxide, and the alkali metal hydroxide is solid or aqueous solution. At a temperature of about 30 to 120 ° C,
After performing the ring closure reaction for 8 hours, excess alkali metal hydroxide and by-product salts are removed by a method such as water washing, and the organic solvent is removed by distillation under reduced pressure to obtain a purified epoxy resin. .

The epoxy resin composition for semiconductor encapsulation of the present invention is a composition comprising the epoxy resin represented by the general formula (I), preferably (II), as an epoxy resin. Another epoxy resin can be used in combination with the epoxy resin. Other epoxy resins that can be used in combination include, for example, bisphenol A, bisphenol F, bisphenol AD, hydroquinone, methylhydroquinone, dimethylhydroquinone, dibutylhydroquinone, resorcinol, methylresorcinol, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxy Diphenyl ether, phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, phenol aralkyl resin, dicyclopentadiene phenol resin,
Various phenols such as terpene phenol resins and naphthol novolak resins, and various phenols such as polyhydric phenol resins obtained by a condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde and glyoxal. Epoxy resins produced from a series compound and epihalohydrin, epoxy resins produced from various amine compounds such as diaminodiphenylmethane, aminophenol, xylenediamine and epihalohydrin, and the like.

In order to make the cured product flame-retardant, a part of the epoxy resin used can be a brominated epoxy resin. As the brominated epoxy resin, for example, an epoxy resin produced from a brominated bisphenol A or a brominated phenol novolak resin and epihalohydrin, an epoxy resin produced by reacting a low molecular epoxy resin with a brominated bisphenol A, and the like Is mentioned.

In the epoxy resin composition of the present invention, the proportion of the epoxy resin represented by the above general formula (I), preferably (II), in all epoxy resins is preferably at least 50% by weight. If the amount of the epoxy resin of the present invention is too small,
The effect of the present invention of forming a cured product for sealing a semiconductor having high heat resistance and excellent in low moisture absorption and low stress cannot be sufficiently exhibited.

The epoxy resin curing agent (b) used in the epoxy resin composition for semiconductor encapsulation of the present invention is a phenolic and / or modified phenolic epoxy resin curing agent. As 1
A compound having an average of two or more phenolic hydroxyl groups in the molecule, for example, bisphenol A, bisphenol F, bisphenol AD, hydroquinone, resorcin, methylresorcin, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenylether, phenol novolak resin , Cresol novolak resin, bisphenol A novolak resin, phenol aralkyl resin, dicyclopentadiene phenol resin, terpene phenol resin, naphthol novolak resin, brominated bisphenol A, various polyhydric phenols such as brominated phenol novolak resin,
Examples include various phenol resins such as polyhydric phenol resins obtained by a condensation reaction of various phenols with various aldehydes such as benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, and glyoxal.

Examples of the modified phenolic epoxy resin curing agent include active ester compounds obtained by esterifying all or a part of the phenolic hydroxyl groups of phenolic resins, such as by benzoate or acetate. Among these epoxy resin curing agents, phenol novolak resin,
At least one epoxy resin curing agent selected from a phenol aralkyl resin, a dicyclopentadiene phenol resin, and a terpene phenol resin is preferable. The amount of the epoxy resin curing agent (b) used in the epoxy resin composition for semiconductor encapsulation of the present invention reacts with the epoxy groups of all epoxy resin curing agent components per 1 mol of epoxy groups in all epoxy resin components. The total of the groups is preferably 0.5 to 1.5 mol, more preferably 0.7 to 1.3 mol.

The curing accelerator (c) used in the epoxy resin composition of the present invention is a compound which promotes the reaction between the epoxy group in the epoxy resin and the active group in the curing agent. Examples of the curing accelerator include tributylphosphine, triphenylphosphine, tris (dimethoxyphenyl) phosphine, and tris (hydroxypropyl).
Phosphine compounds such as phosphine and tris (cyanoethyl) phosphine; phosphonium salts such as tetraphenylphosphonium tetraphenylborate, methyltributylphosphonium tetraphenylborate and methyltricyanoethylphosphonium tetraphenylborate; 2-methylimidazole, 2-phenylimidazole; Ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole,
2,4-dicyano-6- [2-methylimidazolyl-
(1)]-Ethyl-S-triazine, 2,4-dicyano-6- [2-undecylimidazolyl- (1)]-imidazoles such as ethyl-S-triazine, 1-cyanoethyl-2-undecylimidazo Lium trimellitate,
Imidazolium salts such as 2-methylimidazolium isocyanurate, 2-ethyl-4-methylimidazolium tetraphenylborate, 2-ethyl-1,4-dimethylimidazolium tetraphenylborate, 2,4,6
-Tris (dimethylaminomethyl) phenol, benzylmethylamine, tetramethylbutylguanidine, N-
Amines such as methylpiperazine and 2-dimethylamino-1-pyrroline, ammonium salts such as triethylammonium tetraphenylborate, 1,5-diazabicyclo (5.4.0) -7-undecene, 1,5-diazabicyclo (4 3.3.0) -5-Nonene, 1,4-diazabicyclo (2.2.2) -octane and other diazabicyclo compounds, tetraphenylborate, phenol salt, phenol novolak salt and 2-ethylhexanoate of these diazabicyclo compounds And the like.

Among the compounds that serve as curing accelerators, phosphine compounds, imidazole compounds, diazabicyclo compounds, and salts thereof are preferred. These curing accelerators are used alone or as a mixture of two or more,
The amount used is 0.1 to 0.1% based on all epoxy resin components.
7% by weight.

Next, the epoxy resin composition for semiconductor encapsulation of the present invention contains (d) an inorganic filler. Examples of the type of the inorganic filler include fused silica, crystalline silica, glass powder, alumina, and calcium carbonate. Its shape is crushed or spherical. Various inorganic fillers may be used alone or in combination of two or more. Among various inorganic fillers, crushed or spherical fused silica or crystalline silica is preferable, and the used amount is 60 to 95% by weight of the whole composition, and more preferably,
70 to 93% by weight, more preferably 80 to 92% by weight.
% By weight.

The epoxy resin composition for semiconductor encapsulation of the present invention may optionally contain a coupling agent, a plasticizer, a pigment, a solvent, a flame retardant, and the like, if necessary. Further, antimony trioxide, phosphoric acid and the like can be appropriately blended as a flame retardant auxiliary.

[0027]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to the Examples unless it exceeds the gist thereof.

Production Example 1 A 6-liter three-necked flask equipped with a thermometer, a stirrer, and a condenser was charged with 6,6'-dihydroxy-4,4,4 ',
100 g of 4 ', 7,7'-hexamethyl-bis-2,2'-spirochroman, 352 g of epichlorohydrin, and 137 g of isopropyl alcohol were charged, and the mixture was heated to 50 ° C and uniformly dissolved. After allowing this to cool to 35 ° C., 95 g of a 48.5% by weight aqueous sodium hydroxide solution was added dropwise over 1 hour. During this period, the temperature was gradually raised so that the temperature in the system reached 65 ° C. at the end of the dropping. Then 65
The reaction was carried out at a temperature of 30 ° C. for 30 minutes. After the completion of the reaction, the product was washed with water to remove by-product salts and excess sodium hydroxide. Next, excess epichlorohydrin and isopropyl alcohol were distilled off from the product under reduced pressure to obtain a composition epoxy resin. This epoxy resin composition was dissolved in 195 g of methyl isobutyl ketone, 2 g of a 48.5% by weight aqueous sodium hydroxide solution was added, and the mixture was reacted at a temperature of 65 ° C. for 1 hour. After the completion of the reaction, sodium phosphate monobasic was added to neutralize the excess sodium hydroxide, and washed with water to remove by-product salts. Next, methyl isobutyl ketone was completely removed under reduced pressure to obtain a light brown resin. The epoxy equivalent was 249 g / eq, the softening point was 75 ° C, and the melt viscosity at 150 ° C was 0.3P. When the resin in a molten state was allowed to cool while stirring, a yellow-white crystalline resin was obtained. Melting point was 148 ° C.

Production Example 2 6,6'-dihydroxy-4,4,4 used in Production Example 1
4 ', 4', 7,7'-Hexamethyl-bis-2,2 '
-Instead of 100 g of spirochroman, 6,6'-dihydroxy-4,4,4 ', 4', 5,5 ', 7,7'-
Octamethyl-bis-2,2'-spirochroman 108
g and reacted with epichlorohydrin in the same manner as in Production Example 1 and post-treated to give an epoxy equivalent of 265 g / eq.
An epoxy resin having a softening point of 68 ° C. and a melt viscosity of 0.4 P at 150 ° C. was obtained.

Example 1 Epoxy Resin Composition for Semiconductor Encapsulation
And Comparative Examples 1-2 As shown in Table 1, (a) the epoxy resin was derived from each of the epoxy resins obtained in Production Examples 1 and 2, an ortho-cresol novolak-type epoxy resin, or tetramethylbiphenol. Epoxy resin, and brominated bisphenol A type epoxy resin as a brominated epoxy resin,
(B) A phenol novolak resin and a phenol aralkyl resin as an epoxy resin curing agent, (c) crushed fused silica powder as an inorganic filler, (d) trisphenylphosphine as a curing accelerator, and trioxide as a flame retardant aid. Using antimony, epoxy silane as a filler surface treatment agent, and carnauba wax as a release agent,
Each epoxy resin composition was blended.

Next, each composition was melt-mixed at 70 to 130 ° C. for 5 minutes using a mixing roll. Each of the obtained molten mixtures was taken out in a sheet shape and pulverized to obtain each molding material. Using each of these molding materials, a low pressure transfer molding machine is used to mold at a temperature of 175 ° C. and a molding time of 160 to 3 hours.
Molding was performed in 00 seconds to obtain a TMA test piece, a moisture absorption measurement test piece, and a 44-pin FPP (flat plastic package) encapsulating the simulated element, and were post-cured at 180 ° C. for 8 hours.

(Evaluation) The results of testing the glass transition temperature, moisture absorption, and solder heat resistance after post-curing of each test piece are as shown in Table 1. The molding materials of Examples 1 to 3 are comparative examples. Glass transition temperature is higher than those of molding materials 1 and 2,
A cured product having low hygroscopicity and excellent solder heat resistance was obtained. It is considered that the excellent solder heat resistance is due to the low stress property, low moisture absorption property and high glass transition temperature of these molding materials, which were suitable for semiconductor encapsulation.

[0033]

[Table 1]

Notes on Table 1: * 1: Orthocresol novolak type epoxy resin (Yuka Kasper Epoxy Co., Ltd. Epicoat 180S65,
Epoxy equivalent: 213 g / eq) * 2: Epoxy resin derived from tetramethylbiphenol (trade name of Yuka Shell Epoxy Co., Epicoat YX)
4000H, epoxy equivalent: 193 g / eq) * 3: phenol novolak resin (manufactured by Gunei Chemical Co., hydroxyl equivalent: 103 g / eq, softening point: 85 ° C) * 4: phenol aralkyl resin (trade name of Mitsui Toatsusha)
Millex XL225LL, hydroxyl equivalent: 173 g / e
q, softening point: 78 ° C) * 5: Fragmented fused silica powder (trade name: Tatsumori RD-
8) * 6: Brominated bisphenol A-type epoxy resin (Eicoat 5050, trade name of Yuka Shell Epoxy, epoxy equivalent: 385 g / eq, bromine content: 49%) * 7: Epoxysilane (trade name of Shin-Etsu Chemical Co., Ltd. KBM)
-403) * 8: Calculated from the transition point of the thermal expansion curve using TMA. * 9: Moisture absorption after 168 hours at 85 ° C. and 85% RH * 10: 16 44-pin FPPs were absorbed at 85 hours at 85 ° C. and 85% RH for 16 seconds, then immersed in a 260 ° C. solder bath for 10 seconds, and the number of cracks generated I asked.

[0035]

The epoxy resin composition for encapsulating a semiconductor of the present invention has high heat resistance and can give a cured product having excellent low moisture absorption and low stress, which is advantageous in semiconductor encapsulation applications. Can be used for

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 23/31

Claims (7)

[Claims] (A) a solid represented by the following general formula (I):
Pyrochroman skeleton-containing epoxy resin, (b) phenolic and / or modified phenolic epoxy
A semiconductor comprising a resin curing agent, (c) a curing accelerator, and (d) an inorganic filler as essential components.
Epoxy resin composition for body sealing. Embedded image(Where R₁, R_Two, R_ThreeAnd R_FourIs a hydrogen atom or charcoal
Represents a hydrocarbon group with a prime number of 1 to 6,
It may be. R_Five, R₆, R₇, R₈, R ₉as well as
R_TenIs a hydrogen atom, a halogen atom or a carbon atom having 1 to 6 carbon atoms.
Represents a hydride group, which may be the same or different
No. N is an average value of 0 to 5) 2. The spirochroman skeleton-containing epoxy resin represented by the general formula (I) of the component (a) is represented by the following general formula (I)
The epoxy resin composition according to claim 1, which is a spirochroman skeleton-containing epoxy resin represented by I). Embedded image (Wherein R ′ ₁ , R ′ ₂ , R ′ ₃ and R ′ ₄ represent a methyl group. R ′ ₅ , R ′ ₆ , R ′ ₇ , R ′ ₈ , R ′ ₉
And R _'10 represents a hydrogen atom or a methyl group, may each be the same or different. N 'is an average of 0 to 5) 3. An epoxy resin having a spirochroman skeleton represented by the general formula (I):
3. The epoxy resin composition according to claim 1, wherein the epoxy resin composition comprises 0 to 50% by weight and an epoxy resin having another structure. 4. The method according to claim 1, wherein at least one selected from the group consisting of phenol novolak resin, phenol aralkyl resin, dicyclopentadiene phenol resin and terpene phenol resin is blended as an essential component as component (b). The epoxy resin composition according to claim 1. 5. A group which reacts with the epoxy group in the component (b) in an amount of from 0.5 to 1 mol of the epoxy group in the component (a).
(1) The component (b) is used in an amount of 2.0 mol.
5. The epoxy resin composition according to any one of items 4 to 4. 6. The epoxy resin composition according to claim 1, wherein component (c) is compounded in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of component (a). 7. As the component (d), 60 to 60% of the total amount of the composition
The epoxy resin composition according to any one of claims 1 to 6, wherein 95% by weight of a crushable and / or spherical, fused and / or crystalline silica powder filler is used.