JPH06220168A - Resin-sealed semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the subject semiconductor device, excellent in heat cycle and moisture resistance, etc., and useful as an integrated circuit, etc., by sealing a semiconductor device with a resin composition comprising an epoxy resin, a specific curing agent and silicon nitride. CONSTITUTION:The objective semiconductor device is sealed with a resin composition comprising (A) an epoxy resin having 170-300 epoxy equiv. such as a novolak type, (B) a curing agent having plural phenolic hydroxyl groups in the molecule such as novolak type phenolic resin and (C) fiber or whisker of silicon nitride. The resin composition of the objective semiconductor device comprises the components (A) and (B) at a blending ratio of 0.5-1.5 expressed in terms of equiv. ratio of the phenolic hydroxyl groups in the component (B) to the epoxy groups in the component (A) and the component (C) is blended in an amount of 0.1-1000 pts.wt. based on 100 pts.wt. total amount of the components (A) and (B). Furthermore, fused silica or crystalline silica or both are preferably contained in this resin composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device using an epoxy resin composition for encapsulation.

[0002]

2. Description of the Related Art Epoxy resin compositions are used in integrated circuits (I
C), large-scale integrated circuits (LSI), semiconductor devices such as transistors, or other electronic parts are used as encapsulating materials.

In recent years, in particular, semiconductor devices are required to have high reliability, so that the epoxy resin composition used for encapsulating such semiconductor devices also has high reliability. Sex is required.

Such an epoxy resin composition for sealing is
First, changes in the ambient temperature must not damage the internally sealed components. Such temperature characteristics can be evaluated as, for example, heat resistance cycle characteristics. That is, in this evaluation test, a semiconductor device encapsulated with an epoxy resin composition is sequentially exposed to high temperature and low temperature to form one cycle, and the characteristics of the semiconductor device are measured for each cycle, and the characteristic cycle is evaluated. It is to evaluate whether or not the decrease in

By the way, in the conventional semiconductor device encapsulated with the epoxy resin composition for encapsulation, when the component is mechanically stressed by the encapsulating resin body during the heat resistance cycle characteristic test, However, there is an inconvenience in that the bonding wire cannot withstand this stress, and the bonding wire causes cutting or poor contact.

Further, in the conventional resin-encapsulated semiconductor device, in a high temperature and high humidity environment, moisture penetrates the encapsulating resin body to reach the internal device, and as a result, for example, aluminum wiring corrodes. There are problems such as easy to do.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly reliable resin-encapsulated semiconductor device encapsulated with an epoxy resin composition, which solves the conventional problems.

[0008]

Means for Solving the Problems The present inventor has achieved the above object.
The components of epoxy resin composition for encapsulation to be achieved
As a result of repeated studies, as one of the components, as will be described later
Silicon nitride (Si₃ N _FourThe above disadvantages
Has been improved and a highly reliable resin-sealed semiconductor device has been obtained.
I found that

That is, the sealed semiconductor device of the present invention is
A resin composition containing (a) an epoxy resin, (b) a curing agent composed of a compound having two or more phenolic hydroxyl groups in one molecule, and (c) a silicon nitride fiber or a whisker. It is characterized by

In the encapsulating epoxy resin composition used in the present invention, the epoxy resin which is the first essential component may be any one known in the art and is not particularly limited. Specific examples include glycidyl ether type epoxy resins such as bisphenol A type epoxy resin and phenol novolac type epoxy resin; glycidyl ester type epoxy resin; glycidyl amine type epoxy resin; linear aliphatic epoxy resin; alicyclic epoxy resin; complex. Cyclic epoxy resins; epoxy resins having two or more epoxy groups in one molecule such as halogenated epoxy resins. These epoxy resins may be used alone or in a mixture of two or more kinds.

Of these, a preferred epoxy resin is a novolac type epoxy resin having an epoxy equivalent of 170 to 300, and examples thereof include a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a halogenated phenol novolac type epoxy resin.

Further, it is desirable that these epoxy resins have a chlorine ion content of 10 ppm or less and a hydrolyzable chlorine content of 0.1% by weight or less. The reason for this is 10
This is because if chlorine ions in excess of ppm or hydrolyzable chlorine in excess of 0.1% by weight is contained, the sealed semiconductor device, such as the Al electrode, is easily corroded.

Next, the second essential component, the curing agent, is
There is no particular limitation as long as it is a compound having two or more phenolic hydroxyl groups in one molecule, and a phenol resin, a phenol aralkyl resin, polyoxystyrene, a polyhydric phenol compound or the like can be used.

Specifically, for example, novolac type phenolic resins such as phenol novolac resin, cresol novolac resin, tert-butylphenol novolac resin and nonylphenol novolac resin; resole type phenolic resin; polyoxystyrene such as polyparaoxystyrene; bisphenol A And halides of these compounds. Of these, novolac type phenol resin, phenol aralkyl resin and polyoxystyrene are particularly preferable. Further, these curing agents may be used alone or in a mixture of two or more kinds.

The blending ratio of the epoxy resin and the curing agent is not particularly limited, but in consideration of two points of promotion of the reaction and characteristics of the cured product obtained, the number of phenolic hydroxyl groups of the curing agent and the epoxy group. The ratio of the number of epoxy groups in the resin (number of phenolic hydroxyl groups / number of epoxy groups) is 0.5 to
It is preferable to mix them in a range of 1.5.

Further, the resin composition used in the present invention contains silicon nitride (Si ₃ N ₄ ) fibers or whiskers as a third essential component. S as fibrous Si ₃ N ₄
i ₃ N ₄ long fibers cut into pieces with a diameter of 1
It is possible to cut long fibers of about 20 μm to a length of 1 mm or less before use. As the whiskers, those having a diameter of 0.1 to 1 μm and a length of 50 to 300 μm can be used. The silicon nitride fiber and the whiskers can be used together.

The amount of Si ₃ N ₄ blended is not particularly limited, but is preferably in the range of 0.1 to 1000 parts by weight with respect to 100 parts by weight of the total of the epoxy resin and the curing agent. . If the blending amount is less than 0.1 parts by weight, the effect of the addition is not recognized, and if it exceeds 1000 parts by weight, the fluidity of the entire resin composition deteriorates. Further, it is preferable that this Si ₃ N ₄ is used after being treated with a surface treatment agent such as a silane coupling agent in order to further improve the characteristics of the resin-sealed semiconductor device.

Since Si ₃ N ₄ is excellent in heat resistance, chemical stability and electric insulation, the characteristics of the resin-encapsulated semiconductor device can be improved by blending it.

Since Si ₃ N ₄ has a high thermal conductivity, the heat dissipation characteristics of the resin-sealed semiconductor device are also improved. Comparing this with other thermally conductive fillers, such as magnesia, alumina, and silicon carbide-containing encapsulation semiconductor devices, the encapsulation-type semiconductor device of the present invention is superior in moisture resistance or electrical characteristics to those described above. Excellent insulation.

Further, Si ₃ N ₄ has a small coefficient of thermal expansion (about 1/2 that of silicon carbide, about 1/3 that of alumina and magnesia).
~ 1/4), greatly contributes to the reduction of the thermal expansion coefficient of the resin composition.

In the resin composition used in the resin-encapsulated semiconductor device of the present invention, it is preferable to add, for example, a known inorganic filler or curing accelerator in addition to the above-mentioned essential components.

Examples of the inorganic filler include fused silica, crystalline silica, glass fiber, talc, alumina, calcium silicate, calcium carbonate, barium sulfate, magnesia, and the like. Among them, fused silica, crystalline Silica is preferred because it has high purity and low thermal expansion property.

In particular, the amount of the silica compounded is 0.1 with respect to 100 parts by weight of the resin component (epoxy resin and curing agent).
When the amount is in the range of up to 1000 parts by weight, the advantages of Si ₃ N ₄ and silica are effectively combined, and a sealed semiconductor device having excellent characteristics can be obtained.

On the other hand, the curing accelerator is a component that contributes to shortening the curing time of the resin and improving the properties of the cured product. In the present invention, it is particularly desirable to use an organic phosphine compound.

Specific examples of such organic phosphine compounds include phenylphosphine, octylphosphine, diphenylphosphine, butylphenylphosphine, methyldiphenylphosphine, tricyclohexylphosphine, tributylphosphine, triphenylphosphine,
Triphenylphosphine oxide, and further 1,2-
Examples thereof include bis (diphenylphosphino) ethane and bis (diphenylphosphino) methane. These compounds may be oxidized after sealing and contained in the form of oxide.

Of these, arylphosphine compounds such as triphenylphosphine, 1,2-bis (diphenylphosphino) ethane, bis (diphenylphosphino) methane and the like are particularly preferable. These organic phosphine compounds may be used alone or in a mixture of two or more.

The composition ratio of this organic phosphine compound is 0.01 to 20 of the resin components (epoxy resin and curing agent).
Although it may be wt%, it is particularly preferably in the range of 0.01 to 5 wt%.

The encapsulating epoxy resin composition of the present invention includes
Further, if necessary, other additives such as natural waxes, synthetic waxes, metal salts of linear fatty acids, release agents such as acid amides, esters or paraffins, chlorinated paraffin, bromotoluene, hexa and the like. Flame retardants such as brombenzene and antimony trioxide, colorants such as carbon black, silane coupling agents and the like may be appropriately added and blended.

Any method may be used for preparing the above-mentioned encapsulating epoxy resin composition as a molding material, and the raw material components selected in the above predetermined composition ratio are thoroughly mixed by, for example, a mixer. After that, a method of applying a melt mixing treatment with a hot roll, a mixing treatment with a kneader, or the like can be applied.

On the other hand, the resin-sealed semiconductor device of the present invention is
It can be easily manufactured by encapsulating a semiconductor device using the encapsulating epoxy resin composition. The most common sealing method is a low-pressure transfer molding method, but sealing by injection molding, compression molding, casting or the like is also possible. The epoxy resin composition is heated and cured during encapsulation, and finally a resin-encapsulated semiconductor device encapsulated with the cured product of this composition can be obtained. Heating at 150 ° C. or higher is particularly desirable for curing.

The semiconductor device in the present invention is an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode, etc., and is not particularly limited.

[0032]

EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be described in detail below with reference to Examples and Comparative Examples.

Examples 1 and 2 and Comparative Examples 1 to 4 [I] Preparation of transfer molding material (1) Epoxy equivalent of 220 cresol novolac type epoxy resin (epoxy resin A), (2) Epoxy equivalent 2
90 brominated epoxy novolac resin (epoxy resin B), (3) curing agent of 700 molecular weight phenol novolac resin, (4) silicon nitride fiber having an average diameter of 8 μm, average length of 100 μm, (5) average diameter of 0.5 μm , Silicon nitride whiskers having an average length of 100 μm, (6) magnesia powder, (7) alumina powder, (8) silicon carbide powder, (9) crystalline silica powder, (10) triphenylphosphine curing accelerator, (11) ) Antimony trioxide, (1
2) carnauba wax, (13) carbon black,
(14) Composition of silane coupling agent (γ-glycidoxypropyltrimethoxysilane) shown in Table 1 (parts by weight)
Chose to. However, regarding the blending amounts of the components (4) to (9), the sum of the volume% of the components (4) to (9) in each example is about 52% of the total composition, and the mutual amounts are adjusted. Were compared. Five kinds of transfer molding materials including comparative examples were prepared by mixing these compositions with a mixer and kneading with a heating roll. [II] Sealing of semiconductor device with resin Transfer molding was performed using the molding material thus obtained, and the MOS type integrated circuit was resin-sealed. The sealing was performed by molding a molding material heated to 90 ° C. by a preheater at 170 ° C. for 2 minutes and further after curing at 180 ° C. for 4 hours. [III] Humidity resistance test (bias PCT) Each of the above 50 resin-sealed semiconductor devices is
A moisture resistance test was conducted by applying 10 V in water vapor of 2 atm to check for disconnection defects due to corrosion of aluminum wiring. The results are shown in Table 2. However, in Comparative Example 4, since semiconductive silicon carbide was used, the insulating property of the sealing resin was poor, short circuit failure occurred in the integrated circuit, and a non-defective product could not be obtained, so it was removed from the test.

[0034]

[Table 1]

[0035]

[Table 2]

Examples 3 to 6 and Comparative Examples 5 to 8 [I] Preparation of Transfer Material Each component used in Examples 1 and 2, and (15) glass fiber (average diameter 9 μm, average length 500 μm) (16) ) A composition having the composition (parts by weight) shown in Table 3 was prepared using fused silica powder. By mixing each composition with a mixer and kneading with a heating roll, including a comparative example, 8
A seed transfer molding material was prepared. [II] Sealing of semiconductor device with resin Transfer molding was performed using the molding material thus obtained, and the MOS type integrated circuit was resin-sealed. The sealing was performed by molding a molding material heated to 90 ° C. by a preheater at 170 ° C. for 2 minutes and further after curing at 180 ° C. for 4 hours. [III] Thermal Cycle Test Next, the thermal cycle test described below was carried out for 100 each of the obtained resin-encapsulated semiconductor devices to evaluate the characteristics. Prepare two constant temperature baths of + 200 ℃ and -65 ℃,
The resin-sealed semiconductor device was placed in a constant temperature bath at + 200 ° C. and left for 30 minutes. Then, it was taken out and allowed to stand at room temperature for 5 minutes, and then left at -65 ° C in a constant temperature bath for 30 minutes. Then, it was taken out and left again for 5 minutes at room temperature. The above operation was set as one cycle, and the heat cycle test was continuously performed. The cycle was interrupted as needed in accordance with the progress of the thermal cycle test, the characteristics of the resin-sealed semiconductor device were measured using a tester, and the occurrence of defects was investigated. The results are shown in Table 4.

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

As is clear from the above description, the resin-encapsulated semiconductor device of the present invention encapsulated with the encapsulating epoxy resin composition is excellent in heat cycle characteristics and moisture resistance and highly reliable. Since it is a thing, its industrial value is great.

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Claims (6)

[Claims] 1. A resin composition comprising (a) an epoxy resin, (b) a curing agent composed of a compound having two or more phenolic hydroxyl groups in one molecule, and (c) a silicon nitride fiber or whiskers. A resin-encapsulated semiconductor device, which is encapsulated. 2. The epoxy resin has an epoxy equivalent of 170.
The device of claim 1 which is a novolac type epoxy resin of 300 to 300. 3. The apparatus according to claim 1, wherein the curing agent is a novolac type phenol resin. 4. The compounding ratio of the epoxy resin and the curing agent is
The apparatus according to claim 1, wherein the equivalent ratio of the phenolic hydroxyl group of the curing agent and the epoxy group of the epoxy resin is in the range of 0.5 to 1.5. 5. The amount of the silicon nitride compounded is 0.1 to 100 relative to 100 parts by weight of the total of the epoxy resin and the curing agent.
A device according to claim 1 in the range of 0 parts by weight. 6. The device according to claim 1, wherein the epoxy resin composition further contains fused silica and / or crystalline silica.