JPH09249795A - Epoxy resin composition and semiconductor sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly reliable epoxy resin composition excellent in humidity resistance, soldering-heat resistance, moldability, nonabrasiveness to molds, etc., by using a specified epoxy resin, a specified phenol polymer, a methyl methacrylate/butadiene/styrene copolymer resin and a spherical alumina powder. SOLUTION: This composition essentially consists of an epoxy resin (A) represented by formula I, a dicyclopentadiene/phenol polymer (B) represented by formula II (wherein R<1> is Cm H2m+1 ; and (m) and (n) are each 0 or an integer of 1 or greater), a methyl methacrylate/butadiene/styrene copolymer resin (C) and a spherical alumina powder (D) having a maximum particle diameter of 100μm and used in an amount of 25-90wt.% based on the entire composition. A semiconductor chip is sealed with a cured product of the composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to moisture resistance, moldability,
The present invention relates to an epoxy resin composition and a semiconductor encapsulation device that have excellent solder heat resistance and a good balance of properties.

[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 resin sealing is economically advantageous as compared with the hermetic sealing method using glass, metal, and ceramic, and is therefore widely used. As the sealing resin, an epoxy resin is generally used among the thermosetting resins 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 use other hardeners. It is widely used as a resin for semiconductor encapsulation because it is superior in moldability and reliability, has no toxicity, and is inexpensive as compared with the resin. 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 surface mounting of semiconductor components and further increase in power consumption, there has been a demand for development of a semiconductor encapsulating resin having good heat dissipation, solder heat resistance, and low stress.

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, good moisture resistance, and a bonding wire open by a hot and cold cycle test. Although it has a feature that it is excellent in resin cracks, pellet cracks, etc., it has a drawback that its function cannot be fulfilled in a power semiconductor with large heat consumption 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 compounding 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 to the high heat conductivity of the sealing resin composition using the crystalline silica powder.

[0004]

The present invention has been made to solve the above-mentioned drawbacks, and is excellent in moisture resistance, solder heat resistance, moldability, especially filling property of thin portion, and die abrasion resistance. , Small thermal expansion coefficient, good thermal conductivity and heat dissipation,
It is an object of the present invention to provide a highly reliable epoxy resin and a semiconductor encapsulation device having a good balance of these characteristics.

[0005]

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

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

[0007]

Embedded image (B) Dicyclopentadiene / phenolic polymer represented by the following general formula

[0008]

[Chemical 6] (However, in the formula, R ² represents C _m H _{2m + 1} , and m and n each represent 0 or an integer of 1 or more.) (C) Methyl methacrylate / butadiene / styrene copolymer resin and (D) maximum particle size An epoxy resin composition comprising a spherical alumina powder of 5 to 100 μm as an essential component, and the silicon nitride powder of (D) described above in a proportion of 25 to 90% by weight with respect to the resin composition. is there. A semiconductor sealing device is characterized in that a semiconductor chip is sealed with a cured product of the epoxy resin composition.

Hereinafter, the present invention will be described in detail.

As the epoxy resin (A) used in the present invention, the one represented by the above chemical formula 5 is used.

The (B) dicyclopentadiene / phenol polymer used in the present invention has a skeleton structure represented by the above general formula 6 and is widely included without being particularly limited in molecular structure, molecular weight and the like. It As a specific polymer, for example,

[0012]

Embedded image

[0013]

Embedded image And the like, and these can be used alone or as a mixture.

Further, a novolac type phenol resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof can be used in combination.

The (C) methylmethacrylate / butadiene / styrene copolymer resin used in the present invention is a copolymer of methylmethacrylate, butadiene and styrene, and is not limited to the composition ratio of each monomer. The mixing ratio of this methyl methacrylate / butadiene / styrene copolymer resin is 0.
It is preferable to mix them so as to contain 1 to 10% by weight.
More preferably, it is in the range of 1.0 to 5.0% by weight. If the proportion is less than 0.1% by weight, there is no effect on the elastic modulus, and if it exceeds 10% by weight, the moldability is poor and it is not suitable for practical use.

The spherical alumina powder (D) used in the present invention has a low impurity concentration and a maximum particle size of 5 to 100 μm, and particularly an average particle size of 5 to 30 μm. If the average particle size exceeds 30 μm, the moisture resistance and the moldability are poor, which is not preferable. The mixing ratio of the spherical alumina powder is 25 to 90% by weight based on the total 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. Further, 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, as essential components, a specific epoxy resin, a specific phenol resin, a methylmethacrylate / butadiene / styrene copolymer resin and a specific spherical alumina powder, which is contrary to the object of the present invention. Release agent such as natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, paraffins, chlorinated paraffins, bromotoluene, hexabromo benzene,
A flame retardant such as antimony trioxide, a coloring agent such as carbon black and red iron oxide, various curing agents and the like can be appropriately added and blended.

The general method for preparing the epoxy resin composition of the present invention as a molding material is as follows: specific epoxy resin, specific phenolic resin, methyl methacrylate / butadiene / styrene copolymer resin, specific spherical alumina. Powder and other raw materials selected to have a predetermined composition ratio are sufficiently mixed with a mixer or the like, and then melt-mixed with a heat roll, and then cooled and solidified and ground into a suitable size to obtain a molding material. be able to. If 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 above-mentioned molding material. 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 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 at the time of encapsulation, and finally a semiconductor encapsulating device encapsulated by the cured product of the composition is obtained. The curing by heating is desirably performed by heating to 150 ° C. or more.

The present invention provides an epoxy resin composition,
By using a specific epoxy resin, a specific phenolic resin, a methylmethacrylate / butadiene / styrene copolymer resin and a specific spherical alumina powder, excellent moisture resistance, solder heat resistance, moldability, and die abrasion resistance, It is possible to obtain a highly reliable resin composition having a small coefficient of thermal expansion, good thermal conductivity, and good heat dissipation, and a well-balanced characteristic thereof. By using this resin composition, a highly reliable semiconductor device can be obtained. Can be manufactured.

[0021]

Next, the present invention will 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 Epoxy resin 13% shown in Chemical formula 5 above, Phenolic resin 11% shown in Chemical formula 7 above, Spherical alumina powder (average particle size 20 μm, maximum particle size 100 μm or less) 71%, 2% of methyl methacrylate / butadiene / styrene copolymer resin and 3% of a release agent were mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material.

Example 2 Instead of 71% of the spherical alumina powder powder used in Example 1, 31% of the spherical alumina powder and crystalline silica powder (average particle size)
A molding material was manufactured in the same manner as in Example 1 except that a mixed powder of 38 μm) and 40% was used.

Comparative Example 1 Cresol novolac epoxy resin (epoxy equivalent 215
) 18%, novolac type phenolic resin (phenol equivalent 107) 8%, spherical alumina powder (average particle size 20 μm, maximum particle size 100 μm or less) 71% and release agent 3% were mixed at room temperature, and Example 1 was mixed. A molding material was produced in the same manner as in.

Comparative Example 2 Instead of the spherical alumina powder in Comparative Example 1, spherical alumina powder (average particle size of 50 μm, maximum particle size exceeding 100 μm) was used.
A molding material was manufactured in the same manner as in Comparative Example 1 except that (150 μm or less) was used.

Semiconductor chips were encapsulated using the molding materials produced in Examples 1-2 and Comparative Examples 1-2, and cured by heating at 170 ° C. to produce semiconductor encapsulation devices. Various tests were performed 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, moisture resistance, and solder heat resistance. It was excellent in moldability and moldability, and the remarkable effect of the present invention could be confirmed.

[0027]

[Table 1] * 1: 50mm in diameter and 3mm in thickness by transfer molding
The molded article was left in a saturated steam at 127 ° C. and 2.5 atm for 24 hours, and measured by the increased weight. * 2: Make a molded product similar to that of the case of water absorption, 175 ℃, 8
After post-curing for a certain time, a test piece of an appropriate size was prepared and measured using a thermomechanical analyzer. * 3: Tested according to JIS-K-6911. * 4: The semiconductor sealing device was measured at room temperature using a rapid thermal conductivity meter (Showa Denko KK, trade name QTM-MD). * 5: Using a 120-cavity 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 * 6: Using a molding material, attach a silicon chip with two or more aluminum wires to a normal 42 alloy frame and transfer mold at 175 ° C for 2 minutes.
Post-curing was performed at 175 ° C for 8 hours. The molded article thus obtained was previously subjected to a moisture absorption treatment at 40 ° C. and 95% RH for 100 hours.
It was immersed in a 250 ° C. solder bath for 10 seconds. After that, 127 ℃
PCT was performed in 2.5 atm of saturated steam, and 50% disconnection due to aluminum corrosion was evaluated as defective. * 7: 8 × 8mm dummy chip with Q-FP (14 × 14 × 1.4
mm) package, transfer molding was performed using the molding material at 175 ° C for 2 minutes, and then post-curing was performed at 175 ° C for 8 hours. The semiconductor encapsulation device obtained in this way is 85 ℃, 85%,
After the moisture absorption treatment for 24 hours, it was immersed in a 240 ° C. solder bath for 1 minute. After that, observe the package surface with a stereo microscope,
The occurrence of external resin cracks was evaluated. * 8: 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.

[0028]

As is apparent from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulating device of the present invention have the moisture resistance, the solder heat resistance, the moldability of the resin composition, especially the filling property of the thin portion. It has excellent mold wear resistance, small coefficient of thermal expansion, good thermal conductivity, and good heat dissipation, and has well-balanced characteristics of these, making it possible to manufacture highly reliable semiconductor encapsulation equipment. is there.

Claims (2)

[Claims] (A) an epoxy resin represented by the following general formula: (B) Dicyclopentadiene / phenolic polymer represented by the following general formula: (However, in the formula, R ¹ represents C _m H _{2m + 1} , and m and n each represent 0 or an integer of 1 or more.) (C) Methyl methacrylate / butadiene / styrene copolymer resin and (D) maximum particle size An epoxy resin composition characterized by containing spherical alumina powder of 5 to 100 μm as an essential component and containing the spherical alumina powder of (D) in a proportion of 25 to 90% by weight with respect to the entire resin composition. Stuff. 2. An epoxy resin represented by the following general formula (A): embedded image (B) Dicyclopentadiene / phenolic polymer represented by the following general formula: (However, in the formula, R ¹ represents C _m H _{2m + 1} , and m and n each represent 0 or an integer of 1 or more.) (C) Methyl methacrylate / butadiene / styrene copolymer resin and (D) maximum particle size A semiconductor chip is obtained by using a cured product of an epoxy resin composition containing spherical alumina powder of 5 to 100 μm as an essential component and containing the spherical alumina powder of (D) in a proportion of 25 to 90% by weight based on the entire resin composition. A semiconductor encapsulation device, comprising: