JPH05230181A - Epoxy resin composition and semiconductor-sealed device - Google Patents

Abstract

PURPOSE:To obtain the subject composition containing a specific epoxy resin and a specific copolymer resin, a specific novolak type phenol resin and a prescribed amount of specific silicon powder, excellent in moisture resistance, moldability, heat resistance, resistance to wear of mold, heat release property and thermal conductivity and useful for electronic parts, etc. CONSTITUTION:The objective composition contains (A) an epoxy resin of the formula ((m) is 0 or 1; (n) is >=1), (B) a novolak type phenol resin, (C) preferably 1.0-5.0wt.% methyl methacrylate.butadiene.styrene copolymer resin and (D) 25-90wt.% silicon nitride powder 0.5-15wt.% surface oxygen concentration by a SiO2 layer and 10-50mum average particle diameter. Furthermore, a semiconductor chip is sealed with a cured product of the composition to provide the objective semiconductor sealed device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition having excellent moisture resistance, moldability and thermal characteristics, and a good balance of characteristics, and a semiconductor encapsulating device.

[0002]

2. Description of the Related Art Conventionally, a method of sealing electronic parts such as diodes, transistors and integrated circuits with a thermosetting resin has been used. This sealing resin is economically advantageous as compared with the hermetic sealing method using glass, metal, and ceramic, and is therefore widely used. Among thermosetting resins, epoxy resins are most commonly used as the encapsulating resin in terms of reliability and price.
Hardeners such as acid anhydrides, aromatic amines, and novolac-type phenolic resins are used as epoxy resins. Among these, epoxy resins using novolac-type phenolic resins as hardeners are those that use other curing agents. Compared with, it is widely used as a resin for semiconductor encapsulation because it is excellent in moldability and moisture resistance, has no toxicity, and is inexpensive. As the filler, fused silica powder or crystalline silica powder is generally used together with the above-mentioned curing agent. In recent years, along with the further increase in power consumption of semiconductor components, there has been a demand for the development of a low-stress resin for semiconductor encapsulation that has good heat dissipation.

However, a resin composition comprising an epoxy resin having a novolac type phenolic resin as a curing agent and a fused silica powder has a small coefficient of thermal expansion and good moisture resistance, and has a bonding wire open-circuited by a hot and cold cycle test. Although it has a feature of being excellent in cracks, pellet cracks, etc., it has a drawback in that it cannot perform its function in a power semiconductor that consumes a large amount of power because of its poor heat dissipation due to its low thermal conductivity. On the other hand, in a resin composition comprising an epoxy resin using a novolac type phenol resin as a curing agent and crystalline silica powder, increasing the blending ratio of the crystalline silica powder increases the thermal conductivity and also improves heat dissipation. However, the coefficient of thermal expansion is large,
There is a drawback in that the reliability with respect to moisture resistance also deteriorates. Further, the sealed product obtained from this resin composition has the drawbacks that the mechanical properties are deteriorated and that the die is largely worn during molding. Therefore, there is a limit in achieving high thermal conductivity of the sealing resin composition using silica powder.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and is excellent in moisture resistance, moldability, especially filling property of thin portion, mold abrasion resistance, and coefficient of thermal expansion. It is intended to provide an epoxy resin composition and a semiconductor encapsulation device which are small in size, have good thermal conductivity and heat dissipation properties, and which are well balanced in their characteristics and have high reliability.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that by using a specific epoxy resin and a specific silicon nitride powder,
The inventors have completed the present invention by finding that the above objects can be achieved.

That is, the present invention provides (A) an epoxy resin represented by the following formula:

[0007]

[Chemical 3] (Wherein m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more) (B) novolac type phenol resin, (C) methyl methacrylate / butadiene / styrene copolymer resin and (D) SiO 2 Silicon nitride powder having a surface oxygen concentration of 0.5 to 15% by _two layers and an average particle size of 10 to 50 μm is an essential component, and the above (D) silicon nitride powder is contained in a ratio of 25 to 90% by weight with respect to the resin composition. It is an epoxy resin composition characterized by being formed. A semiconductor encapsulation device is obtained by encapsulating a semiconductor chip with a cured product of this epoxy resin composition.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, the epoxy resin represented by the following formula is used.

[0010]

[Chemical 4] (Wherein m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more) The novolac type phenol resin (B) used in the present invention includes phenols such as phenol and alkylphenol, and formaldehyde or para. Examples thereof include novolac-type phenol resins obtained by reacting formaldehyde and modified resins thereof, such as epoxidized or butylated novolac-type phenol resins, and these can be used alone or in combination of two or more. The compounding ratio of the novolac type phenol resin is such that the epoxy group (a) of the above (A) epoxy resin and the phenolic hydroxyl group (b) of the novolac type phenol resin of (B)
It is desirable that the molar ratio [(a) / (b)] with () is within the range of 0.1 to 10. If the molar ratio is less than 0.1 or exceeds 10, the moisture resistance, the molding workability and the electrical properties of the cured product deteriorate, which is not preferable in any case.

The (C) methyl methacrylate / butadiene / styrene copolymer resin used in the present invention is not limited to the composition ratio of each monomer as long as it is a copolymer of methyl methacrylate, butadiene and styrene. .. The mixing ratio of this methyl methacrylate / butadiene / styrene copolymer resin is 0.1 with respect to the resin composition.
It is preferably contained in a proportion of ˜10% by weight. More preferably, it is in the range of 1.0 to 5.0% by weight. The proportion is
If it is less than 0.1% by weight, the elastic modulus is not effective, and if it exceeds 10% by weight, the moldability is poor and it is not suitable for practical use.

The (D) silicon nitride powder used in the present invention is obtained by removing coarse particles on a 150 mesh screen and has an average particle diameter of 10 to 50 μm. Average particle size is 10μ
If it is less than m or more than 50 μm, fluidity and workability may be unfavorable. In particular, if the particle size is coarse on a 150-mesh screen, wire gate clogging, wire flow, die wear, etc. may occur during molding, which is not preferable.
On the other hand, if the diameter is too small, the specific surface area increases and the filling property deteriorates. The surface of the silicon nitride to form a Si O ₂ layer by hydrolysis, the oxygen concentration of the surface due to the Si O ₂ layer is desirably in the range from 0.5 to 15%.
If the oxygen concentration is less than 0.5%, the die wear resistance is not effective and the moisture resistance is poor. On the other hand, if it exceeds 15%, the thermal conductivity and the heat dissipation property are lowered, which is not preferable. As silicon nitride that is hydrolyzed, trigonal (α-Si ₃ N ₄ ) or hexagonal (β
—Si ₃ N ₄ ), etc., and these may be used alone or in combination of two or more. The compounding ratio of the silicon nitride powder is preferably 25 to 90% by weight based on the resin composition. If the proportion is less than 25% by weight, the coefficient of thermal expansion increases and the thermal conductivity decreases, which is not preferable. On the other hand, if it exceeds 90% by weight, the dryness becomes large and the moldability is poor and it is not suitable for practical use.

The epoxy resin composition of the present invention contains a specific epoxy resin, a novolac type phenol resin, a methylmethacrylate / butadiene / styrene copolymer resin and a specific silicon nitride powder as essential components, but does not meet the purpose of the present invention. In the limit not to do, and as necessary, for example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids,
Mold release agents such as acid amides, esters, paraffins, chlorinated paraffin, bromtoluene, hexabromobenzene, flame retardants such as antimony trioxide, carbon black,
Coloring agents such as red iron oxide and various curing agents can be appropriately added and blended.

As a general method for preparing the epoxy resin composition of the present invention as a molding material, a specific epoxy resin, a novolac type phenol resin, a methylmethacrylate / butadiene / styrene copolymer resin, a specific silicon nitride powder. , After the other raw material components selected to a predetermined composition ratio are sufficiently uniformly mixed by a mixer or the like, further subjected to a mixing treatment with a hot roll, and then cooled and solidified,
It can be crushed to an appropriate size to obtain a molding material.
When the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic parts or electric parts such as semiconductor devices, excellent properties and reliability can be imparted.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the epoxy resin composition described above. The semiconductor chip to be sealed is not particularly limited to, for example, an integrated circuit, a large scale integrated circuit, a transistor, a thyristor, a diode and the like. The most common method of sealing 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 at the time of encapsulation, and finally a semiconductor encapsulation device encapsulated by the cured product of the composition is obtained. For curing by heating, it is desirable to heat and cure at 150 ° C or higher.

[0016]

The present invention uses a specific epoxy resin, a novolac type phenol resin, a methylmethacrylate / butadiene / styrene copolymer resin and a specific silicon nitride powder in an epoxy resin composition containing a novolac type phenol resin as a curing agent. By this, moisture resistance, moldability,
Excellent mold wear resistance, small coefficient of thermal expansion, thermal conductivity,
It was possible to obtain a highly reliable resin composition having good heat dissipation and well-balanced properties thereof. By using this resin composition, a highly reliable semiconductor sealing device can be manufactured.

[0017]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, “%” means “% by weight”.

Example 1 16% of the epoxy resin of chemical formula 4 was added with 8% of novolac type phenolic resin (phenol equivalent 107) and hexagonal silicon nitride powder (average particle size of 17 μ after removing coarse particles on a 150 mesh sieve).
m, surface oxygen concentration 7%) 71%, methyl methacrylate
Butadiene / styrene copolymer resin 2% and mold release agent 3
% At room temperature, further kneaded at 90 to 95 ° C., cooled and ground to produce a molding material.

Example 2 In Example 1, instead of the hexagonal system silicon nitride powder, a trigonal system silicon nitride powder (average particle size 17 μm with coarse particles removed on a 150-mesh sieve, surface oxygen concentration 7%) was used. 31%
A molding material was manufactured in the same manner as in Example 1 except that a mixed powder of 40% of crystalline silica powder (average particle size: 38 μm) was used.

Comparative Example 1 Cresol novolac epoxy resin (epoxy equivalent 21
5) 16%, novolac type phenolic resin (phenol equivalent 107) 8%, methyl methacrylate butadiene
Styrene copolymer resin 2%, fused silica powder (average particle size 35
μm) 71% and a release agent (3%) were mixed at room temperature to produce a molding material in the same manner as in Example 1.

Comparative Example 2 A molding material was produced in the same manner as in Comparative Example 1 except that crystalline silica powder (average particle size 28 μm) was used in place of fused silica powder in Comparative Example 1.

Comparative Example 3 Cresol novolac epoxy resin (epoxy equivalent 21
5) 18%, novolac type phenolic resin (phenol equivalent 107) 9%, hexagonal silicon nitride powder (average particle size 17 μm after removing coarse particles on 150 mesh sieve) 71%, and mold release agent 3 % Were mixed at room temperature, and a molding material was manufactured in the same manner as in Comparative Example 1.

Comparative Example 4 All the same as Comparative Example 3 except that hexagonal silicon nitride powder (average particle diameter of 60 μm passing through 60 mesh) was used in place of the hexagonal silicon nitride powder in Comparative Example 3. To produce a molding material.

Semiconductor chips were sealed using the molding materials manufactured in Examples 1 and 2 and Comparative Examples 1 to 4 and heat-cured at 170 ° C. to manufacture semiconductor sealing devices. Various tests were conducted on the molding material and the semiconductor encapsulation device, and the results are shown in Table 1. The epoxy resin composition and the semiconductor encapsulation device of the present invention have good thermal characteristics, excellent moisture resistance and moldability, and the effects of the present invention could be confirmed.

[0025]

[Table 1] * 1: Measured according to JIS-K-6911. * 2: The semiconductor sealing device was measured at room temperature using a rapid thermal conductivity meter (Showa Denko KK, trade name QTM-MD). * 3: Using a 120-cavity taking 16-pin P mold, the molding material was transfer-molded at 170 ° C for 3 minutes, and the filling property was evaluated. ○ mark: good, × mark: bad * 4: Using a molding material, a semiconductor chip having two aluminum wirings was transfer-molded at 170 ° C for 3 minutes, and then aged for 8 hours. A humidity resistance test was conducted on 100 of these semiconductor encapsulation devices in high-pressure steam at 121 ° C, and the time at which 50% disconnection (defect occurrence) due to aluminum corrosion occurred was evaluated. * 5: The molding material is preheated, and transfer molding is performed at 175 ° C using a die with a 0.5 mm diameter hard chrome plating material flow hole. It was evaluated by the number of shots when the hole diameter was 5% worn.

[0026]

As is clear from the above description and Table 1, the epoxy resin composition of the present invention and the semiconductor encapsulation device are:
A resin composition having excellent moisture resistance, moldability, particularly filling property in a thin portion, excellent mold wear resistance, small coefficient of thermal expansion, good thermal conductivity and heat dissipation, and well-balanced properties thereof. Therefore, it is a highly reliable semiconductor encapsulation device.

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Claims (2)

[Claims] 1. An epoxy resin represented by the following formula (A): (Wherein m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more) (B) novolac type phenol resin, (C) methyl methacrylate / butadiene / styrene copolymer resin and (D) SiO 2 Silicon nitride powder having a surface oxygen concentration of 0.5 to 15% by _two layers and an average particle size of 10 to 50 μm is an essential component, and the above (D) silicon nitride powder is contained in a ratio of 25 to 90% by weight with respect to the resin composition. An epoxy resin composition comprising: 2. An epoxy resin represented by the following formula (A): (Wherein m represents 0 or an integer of 1 or more, and n represents an integer of 1 or more) (B) novolac type phenol resin, (C) methyl methacrylate / butadiene / styrene copolymer resin and (D) SiO 2 Silicon nitride powder having a surface oxygen concentration of 0.5 to 15% by _two layers and an average particle size of 10 to 50 μm is an essential component, and the above (D) silicon nitride powder is contained in a ratio of 25 to 90% by weight with respect to the resin composition. A cured product of the epoxy resin composition,
A semiconductor encapsulation device comprising a semiconductor chip encapsulated.