JPS61221220A - Epoxy resin sealing composition and semiconductor device sealed therewith - Google Patents

Abstract

PURPOSE:To obtain a resin composition which can give a high-reliability resin- sealed semiconductor device, by mixing an epoxy resin with a specified curing agent and silicon nitride. CONSTITUTION:An epoxy resin composition comprising an epoxy resin (a), a curing agent (b) comprising a compound having at least two phenolic hydroxyl group in the molecule and silicon nitride (c). Preferable examples of the epoxy resins (a) are novolak epoxy resins of an epoxy equivalent of 170-300, such as phenol novolak epoxy resins and cresol novolak epoxy resins. As curing agents (b), novolak phenolic resins, phenol aralkyl resins, etc., are particularly preferable. Silicon nitride (c) is preferred to be in a form of, for example, powder, fiber or whisker.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an epoxy resin composition for sealing and a resin-encapsulated semiconductor device using the same.

[Technical background of the invention and its problems]

Epoxy resin compositions are frequently used as encapsulating materials for integrated circuits (ICs), large-scale integrated circuits (LSIs), semiconductor devices such as transistors, and other electronic components.

In recent years, there has been a growing demand for high reliability, especially for semiconductor devices, and accordingly, high reliability is also required for the epoxy resin compositions used for encapsulating such semiconductor devices. It is being

As described above, the epoxy resin composition for sealing must not damage the internally sealed parts due to changes in ambient temperature. Such temperature characteristics are, for example,
It can be evaluated as heat cycle resistance. That is, in this evaluation test, a semiconductor device sealed with an epoxy resin composition is sequentially exposed to high and low temperatures, which is defined as one cycle, and the characteristics of the semiconductor device are measured for each cycle. This is to evaluate whether a decrease in characteristics was observed.

By the way, in the case of semiconductor devices encapsulated with conventional epoxy resin compositions for encapsulation, the components are subjected to mechanical stress from the encapsulation resin body during the above-mentioned heat cycle characteristic test, and in severe cases cannot withstand this stress, resulting in problems such as breakage of the bonding wire or poor contact.

Furthermore, in conventional resin-sealed semiconductor devices, under high-temperature, high-humidity environments, moisture penetrates the sealing resin body and reaches the internal devices, resulting in corrosion of aluminum wiring, for example. There is a problem.

[Purpose of the invention]

The present invention solves the conventional problems and provides an epoxy resin composition for sealing that can provide a semiconductor device with highly reliable resin sealing, and a resin-sealed semiconductor device sealed with such an epoxy resin composition. With the goal.

[Summary of the invention]

In order to achieve the above object, the inventors of the present invention have conducted various studies on the components of the epoxy resin composition for sealing, and as a result of the results, the present inventors have discovered that silicon nitride (c'mN+) can be added as one of the components to create a sealing epoxy resin composition. It has been found that the above drawbacks can be improved and a highly reliable encapsulating resin composition and a resin-encapsulated semiconductor device using the same can be obtained.

That is, the epoxy resin composition for sealing of the present invention contains (-) an epoxy resin (b) a curing agent consisting of a compound having two or more phenolic hydroxyl groups in one molecule, and (C) silicon nitride. Further, the semiconductor device of the present invention is characterized in that it is sealed with such an epoxy resin.

In the epoxy resin composition for sealing of the present invention, the epoxy resin that is the first essential component may be any commonly known epoxy resin and is not particularly limited. Specific examples include glycidyl ether type epoxy resins such as bisphenol A type epoxy resins and phenol novolac type epoxy resins; glycidyl ester type epoxy resins; glycidylamine type epoxy resins; linear aliphatic epoxy resins; alicyclic epoxy resins; Cyclic epoxy resins include epoxy resins having two or more epoxy groups in one molecule, such as cyclic epoxy resins.

These epoxy resins can be used alone or
A mixed system of the above may be used. Among these, preferred epoxy resins are novolac type epoxy resins having an epoxy equivalent of 170 to 3000, such as phenol novolac type epoxy resins, cresol novolac type epoxy resins, and halogenated phenol novolac type epoxy resins. Furthermore, these epoxy resins desirably 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 that if more than 10 ppm of chlorine ions or more than 0.1% by weight of hydrolyzable chlorine is contained, for example, the At electrode of the sealed life-and-death conductor device is likely to be corroded.

Next, the curing agent, which is the second essential component, contains 2 in 1 molecule.
The compound is not particularly limited as long as it has at least 2 phenolic hydroxyl groups, and phenol resins, phenol aralkyl resins, polyoxystyrene, polyhydric phenol compounds, and the like can be used. Specifically, for example, novolac phenolic resins such as phenol novolac resin, cresol novolac resin, tort-butylpheno-w novolac resin, and nonylphenol novolac resin; resol type phenolic resin; polyoxystyrene such as polyparaoxystyrene, bisphenol. A; and halides of these compounds. Among these, novolak type phenol resins, phenol aralkyl resins and polyoxystyrenes are particularly preferred. Further, these curing agents may be used alone or in a mixed system of two or more.

The compounding ratio of the epoxy resin and the curing agent is not particularly limited, but considering two points: promotion of reaction progress and properties of the obtained cured product, the number of phenolic hydroxyl groups in the curing agent and the epoxy resin It is preferable to blend so that the ratio of the number of groups (number of phenolic hydroxyl groups/number of epoxy groups) is in the range of 0.5 to 1.5.Furthermore, the epoxy resin composition of the present invention contains nitrided as the third essential component. Contains silicon (ci, N,).

Such s + and N4 may be blended in any form, and are preferably in the form of powder, fibers, whiskers, etc., for example. It is preferable to use powdered Si and N having an average particle size of 0.1 to 100 μm in order to improve the fluidity of the entire epoxy resin composition.

On the other hand, fibrous Si and N4 are obtained by cutting long fibers of St and N, for example, with a diameter of 1 to 20 μm.
A material with a length of 50 to 400 cm is cut to a length of 1 cm or less. Furthermore, as a whisker, the diameter is 0.1%1
/JFFm and a length of 50 to 300 μm may be used.

The blending amounts of Si and N are not particularly limited, but are preferably in the range of 0.1 to 1000 parts by weight based on 100 parts by weight of the epoxy resin and curing agent. If the amount is less than 0.1 parts by weight, no effect will be observed, and if it exceeds 1000 parts by weight, the fluidity of the entire resin composition will be reduced. Also,
It is preferable to use this Si and N4 after being treated with a surface treatment agent such as a silane coupling agent in order to further improve the properties of the epoxy resin composition.

Since 5lsN is excellent in heat resistance, chemical stability, and electrical insulation, the properties of the entire epoxy resin composition can be improved by blending it. Furthermore, since Si3N4 has high thermal conductivity, the thermal conductivity of the composition is also improved. Comparing this to epoxy resin compositions containing other thermally conductive fillers, such as magnesia, alumina, and silicon carbide, the epoxy resin compositions of the present invention have superior moisture resistance or electrical insulation properties compared to those mentioned above. is significantly better. Furthermore, Si and N4 have small coefficients of thermal expansion (approximately 1 for silicon carbide and approximately b-''/4 for alumina and magnesia), and greatly contribute to lowering the coefficient of thermal expansion of the resin composition.

In the epoxy resin composition for sealing of the present invention, in addition to the above-mentioned essential components, it is preferable to add and blend, for example, a known inorganic filler and a curing accelerator.

Examples of inorganic fillers include fused silica, crystalline silica, glass fiber, talc, alumina, calcium silicate, calcium carbonate, barium sulfate, magnesia, etc. Among them, fused silica and crystalline silica have high It is preferred because of its purity and low thermal expansion. In particular, the blending amount of these silicas is 0.1 to 1000 parts by weight per 100 parts by weight of the resin component (epoxy resin and curing agent).
When the amount is within the range of parts by weight, the advantages of St, N4, and silica are effectively combined, and an epoxy resin composition for sealing with excellent properties 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, and 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, 1-methyldiphenylphosphine, tricyclohexylphosphine, tributylphosphine, triphenylphosphine, and 1,
Examples include 2-bis(diphenylphosphino)ethane and bis(diphenylphosphino)methane. These compounds also contain arylphosphine compounds, such as tri-722.
Particularly preferred are phosphine, 1,2-bis(diphenylphosphino)ethane, bis(diphenylphosphino)methane, and the like. These organic phosphine compounds may be used alone or in a mixture of two or more. The composition ratio of this organic phosphine compound may be 0.01 to 20 to 11 parts by weight of the resin component (epoxy resin and curing agent), but <IC.

It is preferably in the range of 0.01 to 5% by weight.

The epoxy resin composition for sealing of the present invention may further contain other additives, such as natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, or paraffins, as necessary. W release agent, chlorinated paraffin,
Flame retardants such as bromotoluene, hexabromobenzene and antimony trioxide, colorants such as carbon black, silane coupling agents, etc. may be appropriately added and blended.

Any method may be used to prepare the above-mentioned epoxy resin composition for sealing as a molding material, and after thoroughly mixing the raw ingredients selected in the above-mentioned predetermined composition ratio, for example, with a mixer, Methods such as melting and mixing using hot rolls or mixing using a kneader or the like can be applied.

On the other hand, the resin-sealed semiconductor device of the present invention can be easily manufactured by encapsulating the semiconductor device using the epoxy resin composition for sealing.

The most common method for sealing is low-pressure transfer molding, but sealing by injection molding, compression molding, casting, etc. is also possible. The epoxy resin composition is cured by heating during sealing, and a resin-sealed semiconductor device can finally be obtained by encapsulating the cured product of this composition. It is particularly desirable to heat to 150° C. or higher during curing.

Note that the semiconductor device in the present invention includes an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc., but is not limited to the above.

[Embodiments of the invention]

Example 1.2 and Comparative Examples 1 to 4 (1) Cresol novolac type epoxy resin (epoxy resin A) with an epoxy quotient of 220, (2) Brominated epoxy novolac resin (epoxy resin B) with a z-phoxy equivalent weight of 290, (3) ) 7 enol novolak resin curing agent with a molecular weight of 700, (4) silicon nitride powder with an average particle size of 10 μm,
(5) silicon nitride whiskers with an average diameter of 0.5 μm and an average length of 100 μm, (6) magnesia powder, (7) alumina powder, (8) silicon carbide powder, (9) crystalline silica powder, (10) triphenyl Phosphine curing accelerator, (n) antimony trioxide, (12) carnauba wax, (13) carbon black, (14) silane coupling agent (r-glycidoxypropylene)
K"rutrimethoxysilane) was selected with the composition (parts by weight) shown in Table 1. However, the components (
Regarding the blending amounts of (4) to (9), (4) to (9) in each example
9) The sum of the volumes of the components is approximately 5% of the total composition.
Mutual comparisons were made so that the ratio was 2%.

These compositions were mixed using a mixer and mixed using a heating roll to prepare six transformer 7'' molding materials including a comparative example.

Table 1 Using the molding material thus obtained, transfer molding is performed to create MOS! The integrated circuit was sealed with resin. Sealing was carried out by molding the molding material heated to 90° C. with a preheater at 170° C. for 2 minutes, followed by aftakiering at 180° C. for 4 hours.

Fifty of each of the above resin-sealed semiconductor devices were heated at 120°C.
Humidity test (bias PC
T) was conducted and the results are shown in Table 2. However, Comparative Example 4 was excluded from the test because the insulation of the sealing resin was poor and the integrated circuit was short-circuited, making it difficult to obtain a good product.

Examples 3 to 6 and Comparative Examples 5 to 8 Each component used in Example 1.2 and (15) glass fiber (average diameter 9 μm 1 average length 500 filn) (
16) Compositions having the compositions (parts by weight) shown in Table 3 were prepared using fused silica powder. Eight types of transfer molding materials, including comparative examples, were prepared by mixing each composition with a mixer and mixing with a heated roll! It was made by llI.

Using the molding material thus obtained, the molding material was transfer-molded and the MOa type integrated circuit was sealed with resin. Sealing was performed by heating the molding material to 90°C with a preheater, molding it at 170°C for 2 minutes, and then heating it at 180°C for 4 hours.

Table 3 Next, the obtained resin-sealed semiconductor device was removed.

A thermal cycle test described below was conducted for each piece to evaluate its characteristics.

Prepare two thermostats at +200°C and -65°C, and place the resin-sealed semiconductor device in the thermostat at +200°C for 30 minutes.
Leave it for a minute. Thereafter, it was taken out and left at room temperature for 5 minutes, and then placed in a constant temperature bath at -65°C for 30 minutes. Thereafter, it was taken out and left again at room temperature for 5 minutes. Perform the above operations 1
A thermal cycle test was conducted continuously. As the thermal cycle test progresses, the cycle is interrupted at any time, and the characteristics of the resin-sealed semiconductor device are measured using a tester.
We investigated the occurrence of defects. The results are shown in Table 4.

Table 4 [Effects of the Invention] As is clear from the above explanation, the epoxy resin composition for sealing of the present invention has high reliability. The resin-sealed semiconductor device of the present invention is highly reliable with excellent heat cycle resistance and moisture resistance, and therefore has great industrial value.

Claims (1)

[Claims] 1. Contains (a) an epoxy resin, (b) a curing agent made of a compound having two or more phenolic hydroxyl groups in one molecule, and (c) silicon nitride as essential components. An epoxy resin composition for sealing characterized by: 2. The composition according to claim 1, wherein the epoxy resin is a novolac type epoxy resin having an epoxy equivalent of 170 to 300. 3. The composition according to claim 1, wherein the curing agent is a novolac type phenolic resin. 4. The compounding ratio of the epoxy resin and the curing agent is in the range of 0.5 to 1.5 as an equivalent ratio of the phenolic hydroxyl group of the curing agent to the epoxy group of the epoxy resin. Composition. 5. The composition according to claim 1, wherein the silicon nitride is a powder with an average particle size of 0.1 to 100 μm. 6. The composition according to claim 1, wherein the silicon nitride is silicon nitride fiber. 7. The composition according to claim 1, wherein the silicon nitride is a silicon nitride whisker. 8. The composition according to claim 1, wherein the amount of silicon nitride is in the range of 0.1 to 1000 parts by weight based on 100 parts by weight of the epoxy resin and curing agent. 9. The composition according to claim 1, wherein the epoxy resin composition further contains fused silica and/or crystalline silica. 10. The composition according to claim 1, wherein the epoxy resin composition further contains an organic phosphine compound. 11. Sealed with an epoxy resin composition containing (a) an epoxy resin, (b) a curing agent made of a compound having two or more phenolic hydroxyl groups in one molecule, and (c) silicon nitride. A resin-sealed semiconductor device characterized by: 12. The epoxy resin has an epoxy equivalent of 170 to 300
Claim 1, which is a novolac type epoxy resin of
The device according to item 1. 13. The device according to claim 11, wherein the curing agent is a novolac type phenolic resin. 14. Claim 11, wherein the blending ratio of the epoxy resin and the curing agent is in the range of 0.5 to 1.5 as an equivalent ratio of the phenolic hydroxyl group of the curing agent to the epoxy group of the epoxy resin.
Apparatus described in section. 15. The device according to claim 11, wherein the silicon nitride is a powder with an average particle size of 0.1 to 100 μm. 16. The device according to claim 11, wherein the silicon nitride is silicon nitride fiber. 17. The device of claim 11, wherein the silicon nitride is a silicon nitride whisker. 18. The device according to claim 11, wherein the amount of silicon nitride is in the range of 0.1 to 1000 parts by weight based on 100 parts by weight of the epoxy resin and curing agent. 19. The apparatus according to claim 11, wherein the epoxy resin composition further contains fused silica and/or crystalline silica. 20. The device according to claim 11, wherein the epoxy resin composition further contains an organic phosphine compound.