JPH093167A - Resin composition and resin-sealed semiconductor device made by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition having low viscosity and low moisture absorption and excellent in adherence to a lead frame, heat resistance, etc., by blending an epoxy resin with a curing agent comprising a specified phenol resin and a curing catalyst. SOLUTION: This resin composition is obtained by mixing an epoxy resin (e.g. an o-cresol novolak resin), a curing agent comprising a phenol resin of formula I (wherein (n) is 0 to 10; and R is H, methyl, ethyl, isopropyl, phenyl, chloro or bromo) [e.g. of formula II (wherein (n) is 1 to 10)] and a curing catalyst (e.g. 2-ethylimidazole). A maleimide resin [e.g. poly(phenylene methylene) polymaleimide] can be blended with this composition to improve the high- temperature physical properties. The use of the composition for sealing a semiconductor device can produce a highly reliable resin-sealed semiconductor device having good appearance and excellent in resin crank resistance during high- temperature mounting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition and a resin-encapsulated semiconductor device using the resin composition, and in particular, it has excellent adhesiveness to a lead frame and a package. An object of the present invention is to provide a resin-encapsulated semiconductor device which has a low moisture absorption amount, does not cause resin cracks in a package which is a problem during mounting, and has good reliability over a long period.

[0002]

2. Description of the Related Art Currently, most resin-sealed semiconductor devices are sealed by transfer molding. This method heats and melts an uncured resin tablet containing epoxy resin, a phenol novolac resin as a curing agent, and a filler as a main component, injects it into a mold using a transfer molding machine, and then heats it at a high temperature and high pressure. In this method, the semiconductor chip mounted on the lead frame is sealed by molding and hardening.

The resin-encapsulated semiconductor device manufactured by this method is excellent in reliability because the semiconductor chip is completely covered with the epoxy resin. Further, since it is densely molded using a mold, the package The appearance is also good. for that reason,
At present, most resin-sealed semiconductor devices are manufactured by this method. Further, a resin sealing method such as an injection molding method using a thermoplastic resin or a potting method using a liquid resin has been put into practical use.

On the other hand, in recent years, as semiconductor chips have become larger in size due to higher integration of semiconductor devices, the package of resin-encapsulated semiconductor devices has become larger, and along with the miniaturization of the mounting space, there has been a trend toward thinning. This trend is strengthening, and this trend is expected to become stronger in the future. Furthermore, ASIC
When mounting a gate array called (Application Specific IC) or a surface mount package represented by a standard cell type LSI, processes such as infrared reflow, vapor phase reflow, and solder dipping are adopted.

In these steps, the package is exposed to a high temperature (about 215 ° C. to 260 ° C.). At this time, in the resin-sealed semiconductor device sealed with the resin composition, the resin penetrates to the inside. A small amount of water that has entered may be rapidly vaporized, and the sealing resin may be cracked. When the crack reaches the outside, the reliability of the resin-encapsulated semiconductor device is significantly reduced, which is a serious problem. In addition, there occurs a phenomenon that the sealing resin expands and the package cannot be mounted. Furthermore, in the above process, inside the resin-sealed semiconductor, PSG (phosphosilicate glass) or SiN (silicon nitride) used for the passivation film of the wiring layer of aluminum or the like is cracked, or the Au bonding wire is used. There is also a frequent problem of disconnection. As measures against these, the following requirements are required as a sealing resin used in a large package.

(1) The stress applied to the internal enclosure by the sealing resin is reduced, and the PSG and Si on the sealing resin and the element are reduced.
To improve the adhesion to N, the polyimide film and the lead frame.

(2) To impart high-temperature strength and moisture-absorption high-temperature strength corresponding to the surface mounting temperature to the sealing resin and reduce the amount of moisture absorption.

From the above viewpoints, as the resin main component of the encapsulating resin composition, for example, maleimide resin and P
Practical use of PS (polyphenylene sulfide) resin, PPO (polyphenylene oxide) resin, liquid crystal polymer, and the like is being studied. Furthermore, recently, a maleimide resin, a resin in which a maleimide resin and an epoxy resin are combined, a resin in which a maleimide resin and a phenol resin are combined, or an aminobismaleimide resin prepolymerized by combining a bismaleimide and an amine compound is used as a sealing resin. Proposed.

Further, in the epoxy resin system, the biphenyl epoxy resin system, the naphthol type epoxy resin system, and the like are utilized to reduce the thermal expansion and the moisture absorption due to the high filling of the filler by utilizing the hydrophobic structure of the resin itself and the low viscosity. Resin improvements are being made.

However, there is no encapsulating resin that can sufficiently meet the above-mentioned technical problems, and there is no encapsulating resin that can meet the above-described technical problems as the chip size in the semiconductor package is larger.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has excellent adhesiveness to a lead frame and moisture absorption in response to the increase in size of chips accompanying the high integration of semiconductor elements. An object is to provide a resin composition having a low amount.

Another object of the present invention is to provide a resin composition having a low moisture absorption amount, excellent moldability and high temperature strength.

Still another object of the present invention is that the adhesiveness to the lead frame is excellent, the moisture absorption amount of the package is low, and there is no occurrence of resin cracks in the package, which is a problem during actual layer formation.
It is an object of the present invention to provide a resin-encapsulated semiconductor device having good reliability over a long period of time.

[0014]

The resin composition according to the first aspect of the present invention (claim 1) is (a) an epoxy resin,
It is characterized by containing (b) a phenol resin represented by the following general formula (I), and (c) a curing catalyst as essential components.

Formula (I)

[Chemical 7]

(Wherein n is an integer of 0 to 10 and R is 1 selected from the group consisting of hydrogen atom, methyl group, ethyl group, isopropyl group, phenyl group, chlorine atom and bromine atom.
And Rs may be the same or different. ) It is preferable that the resin composition according to the first aspect of the present invention further contains a maleimide resin. Further, it is preferable to use an organic phosphine compound as the curing catalyst.

The present invention (Claim 5) also provides a resin-encapsulated semiconductor device in which a semiconductor element is encapsulated with the resin composition according to the first aspect.

The resin composition according to the second aspect of the present invention (claim 5) is (a) epoxy resin, (b) phenol resin, (c) polymaleimide having two or more maleimide groups in the molecule. A compound, (d) a curing accelerator, and (e) an azo compound are contained as essential components.

In the resin composition according to the second aspect of the present invention, the azo compound has a decomposition temperature of 1
It is preferable to use one having a temperature of 00 ° C. or higher.

The present invention (claim 7) also provides a resin-encapsulated semiconductor device in which a semiconductor element is encapsulated with the resin composition according to the second aspect.

The resin compositions according to the first and second aspects of the present invention will be described in more detail below.

Specific examples of the epoxy resin used in the resin composition according to the first aspect of the present invention include biphenyl type epoxy resin represented by the following general formula (II), orthocresol novolac resin, tris ( Hydroxyphenyl) methane-based epoxy resins are preferred. These epoxy resins have the function of not only improving the adhesiveness of the cured resin composition, but also improving the moisture resistance reliability and thermal shock resistance, and are preferably used.

General formula (II)

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(Wherein each R, R ² , R ³ , R ⁵ , R ⁶ ,
R ^{2 ′} , R ^{3 ′} , R ^{5 ′} and R ^{6 ′} represent an organic group. ) A specific example of the epoxy resin represented by the general formula (II) is 4,4′-bis (2,3-epoxypropoxy).
Biphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3'-5,5'-tetramethylbiphenyl, 4,4'-bis (2,3-epoxypropoxy)-
3,3'-5,5'-Tetramethyl-2-chlorobiphenyl, 4,4'-bis (2,3-epoxypropoxy)
-3,3'-5,5'-tetramethyl-2-bromobiphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3'-5,5'-tetramethylbiphenyl,
4,4'-bis (2,3-epoxypropoxy) -3,
3'-5,5'-tetrabutylbiphenyl, 4,4'-
Bis (2,3-epoxypropoxy) -3,3'-5,
5'-tetraphenyl biphenyl etc. can be mentioned.

Further, in order to improve the crack resistance,
It is preferable to use a trifunctional epoxy resin represented by the following general formula (III).

General formula (III)

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(In the formula, R ₁ and R ₂ represent an organic group.) Specific examples of the epoxy resin represented by the general formula (III) include EPPN-502 (trade name, manufactured by Nippon Kayaku Co., Ltd., softening point 7).
0 ° C, epoxy equivalent 170), TL-932H (trade name manufactured by Yuka Shell, softening point 63 ° C, epoxy equivalent 171),
ESI-221 (Sumitomo Chemical's trade name, softening point 85 ° C., epoxy equivalent 210) and the like can be mentioned.

As an epoxy resin having high adhesiveness,
A bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a naphthalene type epoxy resin represented by the following general formula, a dicyclopentadiene type epoxy resin, and a phenol aralkyl epoxy resin are also preferable for the purpose of lowering moisture absorption.

[0029]

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[0030]

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[0031]

[Chemical 12]

Further, as the epoxy resin, at least a part thereof is an aromatic condensed ring compound (including monocyclic compounds).
Alternatively, when an epoxy resin in which three or more groups represented by the following general formula are bonded to the same fused ring system of the aromatic fused ring compound derivative is used, the strength at high temperature becomes particularly large.

[0033]

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Aromatic fused ring compounds (including monocyclic compounds)
As, benzene, naphthalene, anthracene, pyrene, pyridine, indene, biphenylene, phenalene,
Phenanthrene, acenaphthylene, fluorene, triphenylene, naphthacene, tetraphenylene, quinoline,
Anthraquinone etc. are mentioned.

As the aromatic condensed ring compound derivative, one or more of a methyl group, an ethyl group, a phenyl group, a cyclohexyl group, a halogen element and the like are bonded to the above aromatic condensed ring compound as a substituent. There are things.

Aromatic fused ring compounds (including monocyclic compounds)
Alternatively, examples of the epoxy resin in which three or more groups represented by the above general formula are bonded to the same fused ring system of the aromatic fused ring compound derivative include the compounds shown below.

[0037]

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Further, as the epoxy resin, when at least a part of the epoxy resin represented by the following general formula and solid at room temperature is used, the epoxy resin exhibits particularly low hygroscopicity, and the lead frame material and the sealing resin are shown. The adhesiveness with is good.

[0039]

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(In the formula, n represents an integer of 0 to 5, R and R'represent one selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group, and R and R'may be the same. They may be different, provided that at least one of R'is a group other than a hydrogen atom.) Furthermore, at least a part of the epoxy resin is
Similarly, when an epoxy resin represented by the following general formula is used, the epoxy resin exhibits particularly low hygroscopicity, and the adhesiveness between the lead frame material and the sealing resin becomes good.

[0041]

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(In the formula, n is an integer of 0 to 5, R and R'represent one selected from the group consisting of a hydrogen atom, an alkyl group and an aryl group, and R and R'are all the same. They may be different, provided that at least one of R'is a group other than a hydrogen atom.) Next, the curing agent used in the resin composition according to the first aspect of the present invention is It is a phenolic resin represented by (I). In the general formula (I), n is 0 to 10, but 0 to 5 is preferable. When n exceeds 10, the viscosity becomes too high and molding becomes difficult. R is at least one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a chlorine atom, and a bromine atom, but in view of ease of synthesis and reliability, a hydrogen atom or a methyl group It is preferably a group.

The phenol resin represented by the above general formula (I) can be synthesized, for example, by heating a phenol monomer and a dimethoxystilbiphenyl compound in the presence of a Friedel-Crafts catalyst and reacting them. is there. The phenol resin preferably has a softening temperature of 150.
C. or less, more preferably 120.degree. C. or less. If the softening temperature is too high, it will be difficult to make the obtained phenol resin highly purified, and the melt-kneading property with the epoxy resin will be deteriorated.

The amount of free phenol as an impurity contained in the phenol resin is preferably 1% or less,
It is more preferably 0.5% or less. When the amount of free phenol is too large, the moisture resistance reliability and the moldability are deteriorated.

Specific examples of the phenol resin include those represented by the following general formula.

[0046]

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In the resin composition according to the first aspect of the present invention, the compounding ratio of the epoxy resin and the phenol resin constituting the resin matrix is such that the number of phenolic hydroxyl groups of the phenol resin as the curing agent and the number of epoxy groups of the epoxy resin are Ratio (number of phenolic hydroxyl groups / number of epoxy groups) is 0.5-
It is desirable to mix them so as to be in the range of 1.5. If this value is less than 0.5, the curing reaction becomes difficult to occur sufficiently, while if it exceeds 1.5, the properties of the cured resin, especially the moisture resistance, are likely to deteriorate. The most preferable compounding ratio is 1
It is.

Further, as the curing catalyst (curing accelerator) used in the resin composition according to the first aspect of the present invention, as long as it can accelerate the curing reaction of the organic resin component for sealing. Although it can be used without particular limitation, organic phosphinic acid is preferable for improving reliability.

Examples of usable curing catalysts include various amines, imidazoles, diazabicycloalkenes, organic phosphines, and metal chelates. Specifically, as the amines, N, N-dimethylcyclohexylamine, N-methyldicyclohexylamine, triethylenediamine, diaminodiphenylsulfone, dimethylaminomethylphenol, benzyldimethylamine, trisdimethylaminomethylphenol and the like are used as imidazoles. , 2-methylimidazole, 2-phenylimidazole, heptadecylimidazole, 2-heptadecylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole and the like,
As diazabicycloalkenes, 1,8-diazabicyclo (5,4,0) undecene-7 (DBU), DBU
Phenol salt (for example, U-CAT SA No.
1) and the like are specific examples of the organic phosphine, trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, methyldiphenylphosphine, dibutylphenylphosphine. , Tricyclohexylphosphine, 1,2
Examples thereof include bis (diphenylphosphine) ethane and bis (diphenylphosphine) methane. These are 1
It can be used in one kind or two or more kinds.

The metal chelates include Al chelates and Zr chelates.

Among these curing catalysts, triphenylphosphine (TPP) and heptadecyl imidazole, which show excellent electrical characteristics in the resin-sealed semiconductor device, are particularly preferable.

In the resin composition according to the first aspect of the present invention, the amount of the curing catalyst added is based on the entire resin composition.
It is preferably 0.5 to 5% by weight.

The resin composition according to the first aspect of the present invention may contain a maleimide resin in order to improve high temperature physical properties. The maleimide resin is not particularly limited, but for example, N represented by the following general formula (IV),
An N′-substituted bismaleimide compound or a poly (phenylene methylene) polymaleimide represented by the following general formula (V) can be used.

General formula (IV)

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(In the formula, X is a divalent hydrocarbon group such as an alkylene group, a cycloalkylene group, a monocyclic or polycyclic arylene group, or --CH _2- , --CO--, --SO ₂
-Or a divalent hydrocarbon group bonded by a divalent atomic group such as -CONH-) General formula (V)

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(In the formula, m represents an integer of 1 to 5) Specific examples of the maleimide resin include N, N'-phenylene bismaleimide, N, N'-hexamethylene bismaleimide and N, N'-. Diphenylmethane bismaleimide, N, N'-oxy-di-p-phenylene bismaleimide, N, N'-4,4'-benzophenone bismaleimide, N, N'-p-diphenylsulfone bismaleimide, N, N'- (3,3'-Dimethyl) methylene-di-
p-phenylene bismaleimide, poly (phenylmethylene) polymaleimide, 2,2-bis (4-phenoxyphenyl) propane-N, N'-bismaleimide, bis (4-phenoxyphenyl) sulfone-N, N'-bis Maleimide, 1,4-bis (4-phenoxy) benzene-N, N'-bismaleimide, 1,3-bis (4-phenoxy) benzene-N, N'-bismaleimide, 1,3
-Bis (3-phenoxy) benzene-N, N'-bismaleimide and the like. These may be used alone or in combination of two or more.

The maleimide resin may contain a small amount of organic acid. This organic acid remains in the resin when the maleimide resin is insufficiently purified, and specific examples thereof include acetic acid, maleic acid, fumaric acid, and fatty acids. Such an organic acid can be extracted from the resin by subjecting the maleimide resin to hot water treatment at 95 ° C. for 20 hours or longer, and can be analyzed by ion chromatography, liquid chromatography or the like.

In the resin composition of the present invention, the content of the organic acid in the maleimide resin greatly affects the physical properties of the cured resin finally formed. That is, when the maleimide resin is not sufficiently purified and a large amount of organic acid remains, it causes a decrease in the moisture resistance of the cured resin to be formed, and when a semiconductor element is encapsulated with a resin composition containing this, a semiconductor chip is formed. Corrosion of the Al wiring layer proceeds. Therefore, the content of the organic acid in the maleimide resin is 0.2% by weight or less, more preferably 0.1% by weight as measured by the extraction and analysis method described above.
It is desirable that the content be not more than weight%.

As a method for producing the maleimide resin, for example, a bismaleimide resin, after synthesis of bismaleamic acid in a reaction solvent, the bismaleamic acid is dehydrated and ring-closed with acetic anhydride to obtain a bismaleimide resin. , And a method for purifying this. Further, a method of purifying this by directly dehydrating and ring-closing a bismaleamic acid with heat in an reaction solvent without using acetic anhydride to obtain a bismaleimide resin can also be mentioned. The method for producing the maleimide resin is not limited to these, but as described above, the latter method is desirable in order to reduce the residual organic acid amount as much as possible.

The compounding amount of the maleimide resin described above is
It is preferably from 5 to 60% by weight based on the entire resin composition.

When the resin composition according to the first aspect of the present invention contains a maleimide resin, it is possible to add a peroxide for the purpose of improving the curability. The following may be mentioned as specific examples of the peroxide.

For example, di-t-butyl peroxide,
Dicumyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, t-butylperoxyacetate, t-butylperoxyphthalate , T-butyl peroxybenzoate, 2,5-
Dimethyl-2,5-dibenzoylperoxyhexane,
Peroxyesters such as t-butylperoxy-2-ethylhexanoate, acetyl peroxide, isobutyryl peroxide, decanoyl peroxide,
Diacyl peroxides such as lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, di-2-ethylhexyl peroxydicarbonate, t-butyl hydroperoxide, cumene hydroperoxide, parameteran Hydroperoxides such as hydroperoxide, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide,
1,1-bis (t-butylperoxy) cyclohexane, 1,1, -bis (t-butylperoxy) -3,
Peroxyketals such as 3,5-trimethylcyclohexane may be used alone or in combination of two or more.

The amount of the peroxide added is preferably 0.1 to 5% by weight based on the total resin composition.

The resin composition according to the first aspect of the present invention is
It may contain an inorganic filler. As the inorganic filler that can be used, quartz glass, fused silica,
Crystalline silica, glass, talc, alumina, calcium silicate, calcium carbonate, barium sulfate, magnesia, silicon nitride, boron nitride, aluminum nitride, aluminum oxide, magnesium oxide, beryllium oxide, mica, etc. can be used. Fused silica, crystalline silica and the like are particularly preferable.

Examples of the shape of the inorganic filler include those processed into fibrous, crushed, pen-like, spherical and sub-spherical shapes, and in consideration of damage to the semiconductor element, particularly spherical and sub-spherical shapes. Those processed are preferable, and those having an average particle size of 30 μm or less are more preferable.

The filling amount of the inorganic filler is preferably in the range of 50 to 95% by weight based on the total amount of the resin composition. If it is less than 50% by weight, the thermal expansion coefficient of the cured product becomes large and the thermal shock resistance becomes insufficient. If it exceeds 95% by weight, the fluidity of the resin composition becomes insufficient, which causes wire flow, bed movement, unfilling, and the like.

Furthermore, for the purpose of lowering the elastic modulus of the present composition, silicone rubber and thermoplastic resins such as various plastic powders, various engineering plastic powders, ABS powders and MBS powders may be added to impart low stress. It is possible. The maximum particle size of the component imparting low stress is 100 μm or less, preferably 50 μm
It is the following.

When the particle size of the inorganic filler and the sealing material of the rubber component is large, the semiconductor element and the bonding wire are damaged during resin encapsulation and the reliability is remarkably lowered.

Next, the resin composition according to the second aspect of the present invention will be described.

The epoxy resin used in the resin composition according to the second aspect of the present invention may be any one as long as it has two or more epoxy groups in one molecule, and its specific example is bisphenol A. Type epoxy resin, novolac type epoxy resin, alicyclic epoxy resin, epoxy compound derived from tri- or tetra (hydroxyphenyl) alkane, bishydroxybiphenyl epoxy resin and the like. These may be used alone or in combination of two or more.

The curing agent used in the resin composition according to the second aspect of the present invention is a phenol resin, and may be any one generally used as a curing agent for epoxy resins. A phenol that can be used as a curing agent
As the resin, for example, phenol novolac resin,
Cresol novolac resin, nonylphenol novolac resin, bisphenol F type novolac resin, bisphenol A type novolac resin, naphthol novolac resin, novolac type phenol resin such as biphenyl structure-containing novolac resin, polyparaoxystyrene, 2, 2 ′
Examples thereof include phenol aralkyl resins such as a condensation polymerization compound of dimethoxy-p-xylene and a phenol monomer, and dicyclopentadiene / phenol polymers. One or more of these phenolic resins are used.

Specific examples of the maleimide resin blended in the resin composition according to the second aspect of the present invention include 2,2'-
Bis (4-phenoxyphenyl) -N, N'-bismaleimide, N, N'-phenylene bismaleimide, N,
N'-hexamethylene bismaleimide, N, N'-diphenylmethane bismaleimide, N.V. N'-oxy-di-
p-phenylene bismaleimide, N, N'-4,4'-
Benzophenone bismaleimide, N, N'-p-diphenylsulfone maleimide, N, N '-(3,3'-dimethyl) methylene-di-p-ferralene bismaleimide,
Bis (4-phenoxyphenyl) sulfone-N, N'-
Bismaleimide, 1,4-bis (4-phenoxy) benzene-N, N'-bismaleimide, 1,3-bis (4-
Phenoxy) benzene-N, N'-bismaleimide,
1,3-bis (3-phenoxy) benzene-N, N'-
Examples thereof include bismaleimide and poly (phenylmethylene) polymaleimide. These may be used alone or in combination of two or more.

In the resin composition according to the second aspect of the present invention, the compounding amounts of the epoxy resin, the phenol resin and the maleimide resin described above can be set as follows. First, the compounding ratio of the epoxy resin and the phenol resin is such that the ratio of the number of phenolic hydroxyl groups of the phenol resin as the curing agent and the number of epoxy groups of the epoxy resin (number of phenolic hydroxyl groups / number of epoxy groups) is in the range of 0.5 to 1.5. It is desirable to blend so that If this value is less than 0.5, the curing reaction becomes difficult to occur sufficiently, while if it exceeds 1.5, the properties of the cured resin, especially the moisture resistance, are likely to deteriorate.

Next, the amount of the maleimide resin compounded is preferably 20 to 80% by weight based on the total amount of the resin matrix composed of the epoxy resin and the phenol resin.
If it is less than 20% by weight, the heat resistance of the cured product will be lowered and the effect of the imide matrix will not appear, and if it exceeds 80% by weight, the moldability of the resin composition will be lowered.

It is more preferable that these three resin components are melt-mixed in advance before the other components described below are added. By performing this treatment, the dispersibility of each resin is improved, and the moldability can be further improved.

The curing catalyst used in the resin composition according to the second aspect of the present invention is not particularly limited as long as it is applicable to the thermosetting resin. For example, an organic phosphine compound, an imidazole compound or a compound thereof. Examples thereof include derivatives, diazabicycloalkenes and basic catalysts. These may be used alone or in admixture of two or more if necessary.

Specific examples of the organic phosphine as the curing catalyst include trimethylphosphine, triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine,
Examples thereof include methyldiphenylphosphine, dibutylphenylphosphine, tricyclohexylphosphine, 1,2-bis (diphenylphosphine) ethane and bis (diphenylphosphine) methane.

Specific examples of the imidazole compound as the curing catalyst include 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecyl imidazole etc. are mentioned.

The compounding amount of the curing catalyst is preferably 0.1 to 10% by weight, and preferably 1.0 to 10% by weight based on the total amount of the resin matrix composed of the epoxy resin and the phenol resin.
It is more preferably 5.0% by weight. 0.1% by weight
If it is less than the above range, the epoxy-phenol curing rate cannot be sufficiently accelerated, resulting in deterioration of moldability. If it exceeds 10% by weight, the heat resistance, moisture resistance, and electrical properties of the cured resin are remarkably deteriorated, and the maleimide curing system is adversely affected, and the moldability is also deteriorated.

The azo compound used in the resin composition according to the second aspect of the present invention is used to accelerate the homopolymerization of the maleimide resin.

Dicumylperoxide (DC, which has been used as a radical polymerization catalyst for maleimide resins in the past)
In the radical generator consisting of an organic peroxide such as P),
When a phenolic hydroxyl group is present in the reaction system, the generated radicals are trapped by these hydroxyl groups, so that the activity is considerably lost, and it cannot be said that the polymerization is sufficiently promoted.

On the other hand, by using a radical generator composed of an azo compound, such a problem was solved and the moldability of the cured resin was improved.

The azo compound has a decomposition temperature of 10 in particular.
It is preferably 0 ° C or higher (measured by DSC), and more preferably 120 ° C or higher. If the decomposition temperature is less than 100 ° C., the curing speed of the resin is too fast, which becomes a factor that hinders the curing of the epoxy resin-phenolic resin, so that the moldability may decrease.

The following can be mentioned as specific examples of the azo compound usable in the present invention.

Azobisisobutyronitrile (AIB
N), decomposition temperature: 100 to 103 ° C. Azobiscyanovaleric acid (ACVA), decomposition temperature: 110
~ 120 ° C 2,2'-azobis- (2-amidinopropane) -dihydroxy chloride (ABAH), decomposition temperature: 163 ~
170 ° C. 1,1′-azobis-1-cyclohexanenitrile (A
CHN), decomposition temperature: 138-143 ° C. 2,2′-azobis-2-methylbutyronitrile (AM
BN), decomposition temperature: 105 to 107 ° C. 2,2′-azobis-2,4-dimethylvaleronitrile (ADVN), decomposition temperature: 97 to 99 ° C. dimethyl-2,2′-azobisisobutyrate ( MAI
B), decomposition temperature: 117 to 121 ° C. The compounding amount of the azo compound is 0.
It is preferably 1 to 5% by weight, and 0.3 to 1% by weight
Is more preferable. If it is less than 0.1% by weight, the curing rate of the maleimide resin cannot be sufficiently accelerated, resulting in deterioration of moldability. If it exceeds 5% by weight, the heat resistance, moisture resistance and electrical properties of the cured product will be significantly reduced.

The resin composition according to the second aspect of the present invention is
It may contain an inorganic filler. Specific examples of the inorganic filler used include fused silica powder, crystalline silica powder, glass fiber, talc, alumina powder, silicon nitride powder, aluminum nitride powder, calcium silicate powder, calcium carbonate powder, barium sulfate powder, magnesia. Powder etc. are mentioned. Of these, fused silica powder and crystalline silica powder are most preferable. As the silica powder, it is preferable to use crushed particles, spherical particles, and fine particles in an appropriate combination.

The amount of the inorganic filler compounded is preferably 50 to 93% by weight, more preferably 82 to 93% by weight of the total resin composition.
It is 91% by weight. If it is less than 50% by weight, sufficient thermal shock resistance cannot be obtained, and if it exceeds 93% by weight, the melt viscosity is too high and the moldability is poor. Further, when the compounding amount is 82% by weight or more, the strength at high temperature remarkably increases.

Although the resin compositions according to the first and second aspects of the present invention have been described above, both of the resin compositions are used as a mold release agent in order to improve the mold releasability from the mold. Hydrocarbon wax, fatty acid wax, fatty acid amide wax, ester wax and the like can be added. Alternatively, it is also effective to apply these release agents to the contact surface with the mold without adding them to the resin composition.

As specific examples of the release agent, ester waxes such as carnauba wax and montan wax are preferable from the viewpoint of moisture resistance, and in addition, long-chain carvone such as stearic acid, palmitic acid, zinc stearate and calcium stearate. Acids and metal salts thereof, low molecular weight polyethylene waxes and the like can be mentioned. These release agents may be used alone or in combination.

In addition, a halogenated epoxy resin, a flame retardant such as antimony trioxide, a coloring agent such as carbon powder, a coupling agent and the like may be added, if necessary.

In the resin composition of the present invention, all solid raw material systems are finely pulverized, pulverized and mixed with a Henschel mixer or the like, and then melt-kneaded with a heating roll, melt-kneaded with a kneader, and melt-kneaded with an extruder. , A special mixer, and an appropriate combination of each of these methods.

A resin-encapsulated semiconductor device obtained by encapsulating a semiconductor element with the resin composition of the present invention is prepared by a conventional method using the above-mentioned resin composition of the present invention (including an inorganic filler). It can be easily manufactured. A general method of resin sealing is low-pressure transfer molding, but injection molding, compression molding, casting or the like is also possible.
Further, a molding method or the like in which an uncured resin sheet relating to the resin composition of the present invention is cut into a predetermined size and pressure-bonded and sealed from the top and bottom of a semiconductor element is also applicable. In this case, after molding,
After-curing at 175 ° C. or higher is desirable.

As described above, the resin composition of the present invention is used not only for resin encapsulation of semiconductor elements, but also for mounting agents, heat-resistant laminated plates, casting materials, and heat-resistant adhesives containing a diluting solvent. It can also be used as a heat resistant paint.

The resin composition according to the first aspect of the present invention is
By using a specific phenolic resin as a curing agent, the viscosity is low compared to conventional resin compositions, as a result,
The filling material can be highly filled, and the amount of moisture absorption under high temperature and high humidity conditions can be suppressed low. In addition, when a semiconductor element is resin-sealed using this resin composition, the lead frame has excellent adhesiveness, and further, the molding time in moldability is shortened, the mold stain is reduced, and It is possible to obtain a resin-encapsulated semiconductor package having excellent releasability and having a good appearance. Furthermore, the formed cured resin has heat resistance, moisture resistance reliability, and suitable as a semiconductor sealing resin.
It has performance such as electrical characteristics.

Therefore, when a large-sized semiconductor element is resin-sealed with the resin composition according to the first aspect of the present invention, resin flacks are not generated during high-temperature mounting, and a resin having good reliability for a long period of time is obtained. It is possible to obtain a sealed semiconductor device.

The resin composition according to the second aspect of the present invention is
The azo compound is used for the epoxy-phenol-maleimide resin system in order to accelerate the homopolymerization of the maleimide resin. Therefore, even if a phenolic hydroxyl group is present in the reaction system, the moldability is not impaired. As a result, the moldability is extremely good, and the strength is high even at high temperatures. A resin composition suitable for sealing is obtained.

[0097]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing Examples and Comparative Examples of the present invention. In addition, the compounding ratio of each composition of the following Examples and Comparative Examples is all% by weight.

(Examples 1 to 8) and (Comparative Examples 1 to 3) A filler component and a resin component were prepared according to the compositions shown in Table 1 below, and the filler component was first charged in a Henschel mixer. The coupling treatment of the filler was performed while mixing at a rotation speed of 4000 rpm. Next, after adding the resin component, further mixing was performed to obtain a powder of a uniform resin composition.

The resin composition powder thus obtained was kneaded using a two-roll mill at a kneading temperature of 90 ° C to 100 ° C. After crushing the kneaded resin powder, a resin tablet was manufactured as a trial using a mold of a predetermined size. Using this tablet, a transfer molding machine equipped with a QFP184pin mold was used to test elements (18 mm □
The chip) was resin-sealed. Resin sealing is performed at a mold temperature of 180
The molding was carried out under the molding conditions of 60 ° C. and a cure time of 60 seconds. Also,
Using a mold capable of molding various test pieces, a molded body was prepared under the same molding conditions.

After the resin-encapsulated semiconductor device obtained was after-cured at 175 ° C. for 8 hours, the lead frame was cut and infrared reflow treatment was performed at 240 ° C.
A moisture resistance reliability test was carried out with a pressure cooker at 2.5 ° C and 2.5 atm. Moreover, after performing the same reflow process, the cooling-heat cycle test of -65-150 degreeC was implemented, and the following characteristics were measured and evaluated.

Molding time: Measured with reference to the presence or absence of blistering of culls and the ease of removing the molded body from the mold. Hardness after molding: Measured with a Barcol hardness meter (# 93
5) Mold release load: A mold release load mold is used to measure the mold release load from the mold body using a push-pull cage.

Mold stain: Molding of the same product in the same mold for 50 shots, and then observing the mold surface for judgment. Appearance of molded product: The presence or absence of sink marks and external cavities was observed by observing the package surface with a microscope.

Further, the following general characteristics were measured for the epoxy resin molding and the uncured epoxy resin powder.

Gel time (180 ° C.) Glass transition temperature coefficient of thermal expansion Bending strength Water absorption rate (85 ° C. 85% 168 hours) Adhesive strength with lead frame: 4 mm ² molded body was formed on the surface of the base material and 175 ° C. for 8 hours After after-curing
Measure the adhesive strength.

The measurement results of the above characteristics are shown in Table 2 below.

[0106]

[Table 1]

[0107]

[Table 2]

As is clear from Tables 1 and 2 above, the resin compositions (Examples 1 to 8) containing all the essential components of the present invention are excellent in all properties,
The resin compositions (Comparative Examples 1 to 3) using phenolic resins outside the scope of the present invention have weak adhesion to the lead frame, low water absorption, and poor reliability test results. You can see that

(Examples 9 to 16 and Comparative Examples 4 and 5) Resin compositions having the compounding compositions shown in Table 3 below were prepared in the following manner (the compounding amounts in the table represent% by weight). That is,
First the filler is treated with a silane coupling agent in a Henschel mixer and then the other ingredients are blended to obtain 60-13
The resin composition for sealing was obtained by kneading with a heating roll at 0 ° C., cooling and then pulverizing.

The following components were used as raw materials.

Epoxy resin A: Orthocresol novolac type epoxy resin (ESCN-195XL, Sumitomo Chemical Co., Ltd., equivalent 197) B: Bisphenol A type brominated epoxy resin (AER-745T, Asahi Kasei Co., Ltd., equivalent) 400) C: Biphenyl type epoxy resin (YX-4000H, manufactured by Yuka Shell Epoxy Co., Ltd., equivalent 192) Curing agent A: Phenol novolac resin (BRG-556, Showa Polymer Co., Ltd., equivalent 104) B : Phenol novolac resin (MEH-7850, manufactured by Meiwa Kasei Co., Ltd., equivalent weight 198) Maleimide resin: DAM type maleimide resin (MB-3000M, manufactured by Mitsubishi Petrochemical Co., Ltd., molecular weight 358) Curing accelerator A: triphenylphosphine (PP-360, manufactured by KI Kasei Co., Ltd.) B: 2-heptadecyl imidazole (C ₁₇ Z, manufactured by Shikoku Kasei Co., Ltd.) C: dicumyl peroxide (DCP, manufactured by NOF CORPORATION) D: 2,2′-azobis-2,4-dimethylvaleronitrile (ADVN, Otsuka Chemical Industry Co., Ltd.) Co., Ltd., decomposition point 97 ° C.) D: Azobisisobutyronitrile (AIBN, Otsuka Chemical Co., Ltd., decomposition point 103 ° C.) E: 1,1′-azobis-1-cyclohexanenitrile (ACHN, Otsuka Chemical Co., Ltd., decomposition point 140 ° C) Release agent: Ester wax Pigment: Carbon black Flame retardant aid: Antimony trioxide Filler: Fused silica powder (average particle size 20 μm) About these resin compositions The following evaluation tests were conducted respectively.

That is, each resin composition was used at 180 ° C. for 2
Create a test piece by transfer molding under the condition of minutes,
After curing at 180 ° C. for 4 hours. For these test pieces, the coefficient of thermal expansion, the glass transition temperature, the bending strength at high temperature, and the water absorption rate were measured.

In order to evaluate the moldability of the resin composition, a lead frame having a dummy chip mounted thereon
Continuous 100 shot molding was performed under conditions of 90 ° C. and 90 ° C. Then, the number of shots at which the breakage of the runner first occurred was observed.

Further, the following test was conducted to examine the reflow crack resistance. That is, after sealing a test device with each resin composition, after-curing was performed at 180 ° C. for 4 hours. Next, this package was left in an atmosphere of 85 ° C. and a relative humidity of 85% for 72 hours for moisture absorption treatment, and then exposed to a fluorocarbon vapor atmosphere of 215 ° C. for 1 minute. At this time, the crack occurrence rate of the package was examined.

The above measurement results are summarized in Table 4 below.

[0116]

[Table 3]

[0117]

[Table 4]

As shown in Tables 3 and 4 above, resin compositions containing all the essential components of the present invention (Examples 9 to 9)
16) is excellent in all properties, but the resin compositions containing no azo compound (Comparative Examples 4 and 5) are inferior in high-temperature bending strength and moldability and have a high crack occurrence rate. .

(Examples 17 to 18 and Comparative Example 6) In the same manner as in Examples 1 to 8, powders of a uniform resin composition having the compositions shown in Table 5 below were obtained. A prototype was produced, and a test molding element (18 mm □ chip) was resin-sealed by using a transfer molding machine equipped with a QFP184 pin mold using this tablet. Resin sealing is
The molding was performed under the molding conditions of a mold temperature of 180 ° C. and a cure time of 60 seconds. Also, using a mold that can mold various test pieces,
A molded body was prepared under the same molding conditions.

After the resin-encapsulated semiconductor device thus obtained was after-cured at 175 ° C. for 8 hours, the lead frame was cut and infrared reflow treatment was performed at 240 ° C.
A moisture resistance reliability test was carried out with a pressure cooker at 2.5 ° C and 2.5 atm. Moreover, after performing the same reflow process, the cooling-heat cycle test of -65 to 150 degreeC was implemented, and the characteristic was measured and evaluated like Example 1-8.

The measurement results of the above characteristics are shown in Table 6 below.

The epoxy resins used are represented by the following formulas, and these are "Synthesis 1
993,487 ”.

[0123]

Embedded image

[0124]

[Table 5]

[0125]

[Table 6]

As is clear from Table 5 and Table 6 above, the resin compositions (Examples 17 and 18) containing all the essential components of the present invention are excellent in all properties, but The resin composition using the phenol resin out of the range (Comparative Example 6) has a weak adhesive force with the lead frame,
It can be seen that the water absorption rate is low and the reliability test results are inferior.

(Examples 19 to 20 and Comparative Example 7) Powders of a uniform resin composition having the compositions shown in Table 7 below were obtained in the same manner as in Examples 1 to 8 and were used to prepare resin tablets. A prototype was produced, and a test molding element (18 mm □ chip) was resin-sealed by using a transfer molding machine equipped with a QFP184 pin mold using this tablet. Resin sealing is
The molding was performed under the molding conditions of a mold temperature of 180 ° C. and a cure time of 60 seconds. Also, using a mold that can mold various test pieces,
A molded body was prepared under the same molding conditions.

After the resin-encapsulated semiconductor device obtained was after-cured at 175 ° C. for 8 hours, the lead frame was cut and infrared reflow treatment was performed at 240 ° C.
A moisture resistance reliability test was carried out with a pressure cooker at 2.5 ° C and 2.5 atm. Moreover, after performing the same reflow process, the cooling-heat cycle test of -65 to 150 degreeC was implemented, and the characteristic was measured and evaluated like Example 1-8.

The measurement results of the above characteristics are shown in Table 8 below.

[0130]

[Table 7]

[0131]

[Table 8]

As is clear from Table 7 and Table 8, the resin compositions (Examples 19 and 20) containing all the essential components of the present invention are excellent in all properties, The resin composition using the phenol resin out of the range (Comparative Example 7) has a weak adhesive force with the lead frame,
It can be seen that the water absorption rate is low and the reliability test results are inferior.

[0133]

As described above in detail, since the resin composition according to the first aspect of the present invention uses a specific phenol resin as a curing agent, the resin composition has a higher viscosity than conventional resin compositions. As a result, the filling material can be highly filled, and the amount of moisture absorption under high temperature and high humidity conditions can be suppressed low. Moreover, when a semiconductor element is resin-sealed using this resin composition, the lead frame has excellent adhesiveness, and further, the molding time in moldability is shortened, and the mold stain is reduced.
It is possible to obtain a resin-encapsulated semiconductor package which has an excellent releasability of the resin composition from the mold and has a good appearance.
Furthermore, the formed cured resin has properties such as heat resistance, moisture resistance reliability, and electrical characteristics suitable as a semiconductor sealing resin.

Further, since the resin composition according to the second aspect of the present invention uses an azo compound as a curing accelerator for the maleimide resin, it has an extremely high moldability as compared with the epoxy-phenol-maleimide resin system. A resin composition that is favorable and exhibits high strength even at high temperatures and is suitable for sealing a surface-mount type semiconductor device can be obtained.

As described above, the resin composition of the present invention can be widely applied to packages having larger semiconductor elements, thinner packages, multi-pin packages, etc., with a low water absorption rate. Since it has a high adhesive force to the inserted metal such as a lead frame, it is possible to realize a highly reliable resin-encapsulated semiconductor device having excellent resin crack resistance during high-temperature mounting.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08L 63/00 NKA C08L 63/00 NKA 65/00 LNY 65/00 LNY H01L 23/29 H01L 23 / 30 R 23/31 (72) Hiromichi Takami, 1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture, Toshiba Research & Development Center Co., Ltd. (72) Inventor Tetsuo Okuyama 1 Komukai-shiba, Kawasaki-shi, Kanagawa Address Incorporated company Toshiba Research and Development Center (72) Inventor Akira Zensaku 1 Komukai Toshiba Town, Kouki-ku, Kawasaki City, Kanagawa Prefecture Incorporated Toshiba Research and Development Center (72) Inventor Hideo Ota Ko, Kozaki, Kawasaki City, Kanagawa Prefecture Muko Toshiba Town No. 1 Inside Toshiba Research and Development Center, a stock company

Claims (12)

[Claims] 1. A resin composition comprising (a) an epoxy resin, (b) a phenol resin represented by the following general formula (I), and (c) a curing catalyst as essential components. General formula (I) (In the formula, n represents an integer of 0 to 10, R represents one or more selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a chlorine atom, and a bromine atom, and each R is the same. But it may be different.) 2. The resin composition according to claim 1, further comprising a maleimide resin. 3. The resin composition according to claim 1, wherein the curing catalyst is an organic phosphine compound. 4. A resin-encapsulated semiconductor device obtained by encapsulating a semiconductor element with the resin composition according to claim 1. 5. An (a) epoxy resin, (b) phenol resin, (c) a polymaleimide compound having two or more maleimide groups in the molecule, (d) a curing accelerator, and (e).
A resin composition comprising an azo compound as an essential component. 6. The resin composition according to claim 5, wherein the decomposition temperature of the azo compound is 100 ° C. or higher. 7. A resin-encapsulated semiconductor device obtained by encapsulating a semiconductor element with the resin composition according to claim 6. 8. At least a part of the epoxy resin comprises:
An epoxy resin in which three or more groups represented by the following general formula are bonded on the same condensed ring system of an aromatic condensed ring compound (including a monocyclic compound) or an aromatic condensed ring compound derivative. The resin composition according to claim 1. Embedded image (In the formula, R represents one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group.) 9. At least a part of the epoxy resin comprises:
The resin composition according to claim 1, which is an epoxy resin represented by the following general formula. Embedded image (In the formula, n is an integer of 3 to 6, R and R'represent one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and R and R'may be the same or different. Good too.) 10. The resin composition according to claim 1, wherein at least a part of the epoxy resin is an epoxy resin represented by the following general formula. Embedded image 11. The resin composition according to claim 1, wherein at least a part of the epoxy resin is an epoxy resin represented by the following general formula and solid at room temperature. Embedded image (In the formula, n is an integer of 0 to 5, R and R'represent one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and R and R'may be the same or different. However, at least one of R'is a group other than a hydrogen atom.) 12. The resin composition according to claim 1, wherein at least a part of the epoxy resin is an epoxy resin represented by the following general formula. [Chemical 6]