JPH09275156A - Epoxy resin composition and semiconductor sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve humidity resistance after bath of molten solder and dipping, solder heat resistance, etc., prevent disconnection due to corrosion of electrodes and generation of leakage current due to water content, and ensure long term reliability, by using specified epoxy resin and specified phenol resin as resin composition. SOLUTION: Epoxy resin shown by formula 1 and dicyclopentadiene.phenol polymer shown by formula 2 where R shows Cm H2m+1 group and (m) and (n) are 0 or integer larger than or equal to 1 are used. Organic filler and hardner are used as inevitable components. Epoxy resin component contains 25-90wt.% of the inorganic filler to the whole resin component. A semiconductor sealing device seals a semiconductor chip by using the cured material of the epoxy resin composition. Thereby the epoxy resin composition and the semiconductor sealing device are excellent in humdity resistance, solder heat resistance, and little affected by moisture absorption, and disconnection of an electrode and generation of leakage current due to water content are reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an epoxy resin composition having excellent moisture resistance and solder heat resistance, and a semiconductor encapsulation device.

[0002]

2. Description of the Related Art In recent years, in the field of semiconductor integrated circuits,
At the same time as the development of high integration and high reliability technologies, automation of the mounting process of semiconductor devices has been promoted. For example, when a flat package type semiconductor device is mounted on a circuit board, soldering has conventionally been performed for each lead pin, but recently, a solder immersion method or a solder reflow method has been adopted.

A conventional semiconductor device sealed with a resin composition comprising an epoxy resin such as a novolac type epoxy resin, a novolac type phenol resin and silica powder is
When the entire device is immersed in the solder bath, there is a drawback that the moisture resistance is lowered. Especially when a semiconductor device that has absorbed moisture is immersed,
Peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and a significant moisture resistance deterioration caused by internal resin cracks, resulting in disconnection due to electrode corrosion and leakage current due to moisture, as a result, The semiconductor device has a drawback in that it cannot guarantee long-term reliability.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and is less affected by moisture absorption, and particularly excellent in moisture resistance after solder bath immersion, solder heat resistance, and sealing resin. Epoxy resin composition that can ensure long-term reliability without peeling between the semiconductor chip or the sealing resin and the lead frame, and without the occurrence of internal resin cracks, or the occurrence of wire breakage due to electrode corrosion or leak current due to moisture Another object of the present invention is to provide a semiconductor sealing device.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above-mentioned object, the present inventor has found that moisture resistance, solder heat resistance, etc. can be improved by using a specific epoxy resin or a specific phenol resin. The inventors have found that an excellent resin composition can be obtained, 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) a dicyclopentadiene / phenol polymer represented by the following general formula,

[0008]

[Chemical 6] (In the formula, R represents a C _m H _{2m + 1} group, and m, n are 0 or 1
Each of the above integers is represented.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the inorganic filler of (C) is contained in a proportion of 25 to 95% by weight with respect to the entire resin composition. It is an epoxy resin composition characterized by containing. 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, those represented by the aforementioned general formula (5) are used. In addition, a novolak epoxy resin, an epibis epoxy resin, and other known epoxy resins can be used in combination with the epoxy resin.

As the dicyclopentadiene / phenol polymer (B) used in the present invention, those represented by the above general formula 6 are used. As a specific compound, for example,

[0012]

Embedded image

[0013]

Embedded image And the like, and these can be used alone or as a mixture. Further, the dicyclopentadiene / phenol polymer may be used in combination with a novolac type phenol resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde and modified resins thereof.

As the inorganic filler (C) used in the present invention, generally used ones are widely used. Among them, silica powder having a low impurity concentration and an average particle diameter of 30 μm or less is preferably used. . If the average particle size exceeds 30 μm, the moisture resistance and moldability are poor, which is not preferable. The blending ratio of the inorganic filler is 25 to 95 with respect to the entire resin composition.
It is preferable to mix it so that it may be contained by weight%. If the proportion is less than 25% by weight, the resin composition has a high hygroscopicity and is inferior in moisture resistance after immersion in solder, and if it exceeds 95% by weight, the fluidity is extremely poor and the moldability is inferior.

As the curing accelerator (D) used in the present invention, a phosphorus curing accelerator, an imidazole curing accelerator, D
A wide range of BU-based curing accelerators and other curing accelerators can be used. These can be used alone or in combination of two or more. It is desirable that the curing accelerator is blended in an amount of 0.01 to 5% by weight based on the total resin composition. If the proportion is less than 0.01% by weight, the gel time of the resin composition will be long and the curing characteristics will be poor, and if it exceeds 5% by weight, the fluidity will be extremely poor and the moldability will be poor.
Furthermore, the electrical characteristics are poor and the moisture resistance is poor, which is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, specific phenolic resin, inorganic filler and curing accelerator as essential components, but it is also necessary as long as the object of the present invention is not impaired. Depending on, for example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, release agents such as paraffins, flame retardants such as antimony trioxide, colorants such as carbon black, A silane coupling agent, a rubber-based or silicone-based low stress imparting agent, and the like can be appropriately added and blended.

A general method for preparing the epoxy resin composition of the present invention as a molding material is to mix the above-mentioned specific epoxy resin, specific phenolic resin, inorganic filler, curing accelerator and other components with a mixer. After sufficiently uniform mixing by means such as the like, melt-mixing treatment with a hot roll or mixing treatment with a kneader etc. is further performed, followed by cooling and solidifying and pulverizing 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.

Further, the semiconductor sealing device of the present invention can be easily manufactured by sealing a semiconductor chip using the molding material 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 sealing method is a low pressure transfer molding method, but sealing by injection molding, compression molding, casting, or the like is also possible. After sealing with a molding material, it is heated and cured, and finally a semiconductor sealing device sealed with this cured product is obtained. The curing by heating is desirably performed by heating to 150 ° C. or more.

The epoxy resin composition and semiconductor encapsulation device of the present invention use a specific epoxy resin and a specific phenol resin to reduce the water absorption of the resin composition and improve the mechanical properties and low stress. However, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and the deterioration of moisture resistance is reduced.

[0020]

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 9.1% of the above-mentioned epoxy resin of Chemical formula 5, 7.9% of the above-mentioned phenolic resin of Chemical formula 7, 82% of silica powder, 0.3% of curing accelerator
%, Ester waxes 0.3% and silane coupling agent 0.4% were mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material (A).

Example 2 4.8% of the same epoxy resin of Chemical formula 5 used in Example 1, 4.2% of the phenolic resin of Chemical formula 7 used in Example 1, 90% of silica powder, 0.3% of curing accelerator, 0.3 of ester waxes %
And 0.4% of a silane coupling agent were mixed at room temperature, kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (B).

Comparative Example 1 o-Cresol novolac type epoxy resin 17%, novolac type phenol resin 8%, silica powder 74%, curing accelerator
0.3%, ester waxes 0.3% and silane coupling agent 0.4% were mixed at room temperature, kneaded and cooled at 90 to 95 ° C, and then pulverized to produce a molding material (C).

Comparative Example 2 20% epibis type epoxy resin, 5% novolak type phenol resin, 74% silica powder, 0.3% curing accelerator, 0.3% ester waxes and 0.4% silane coupling agent.
Was mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (D).

The molding materials (A) to (D) thus produced
Was transferred into a mold heated to 170 ° C., and the semiconductor chip was sealed and cured to manufacture a semiconductor sealing device. Various tests were conducted on these semiconductor sealing devices, and the results are shown in Table 1. The epoxy resin composition and the semiconductor sealing device of the present invention are excellent in moisture resistance and solder heat resistance. The remarkable effect of the invention could be confirmed.

[0026]

[Table 1] * 1: A molded product with a diameter of 50 mm and a thickness of 3 mm was made by transfer molding, left to stand in saturated steam at 127 ° C and 2.5 atm for 24 hours, and measured by the increased weight. * 2: A molded product similar to the case of water absorption was prepared, post-cured at 175 ° C for 8 hours, and a test piece of appropriate size was measured using a thermomechanical analyzer. * 3: Tested according to JIS-K-6911. * 4: Using a molding material, attach a silicon chip with two or more aluminum wires to a normal 42 alloy frame, transfer mold at 175 ° C for 2 minutes, and then at 175 ° C for 8 hours. Cured. The molded product thus obtained was previously subjected to moisture absorption treatment at 40 ° C., 95% RH for 100 hours, and then immersed in a solder bath at 250 ° C. for 10 seconds. After that, PCT was performed in saturated steam at 127 ° C. and 2.5 atm, and 50% disconnection due to corrosion of aluminum was evaluated as defective. * 5: An 8 x 8 mm dummy chip was placed in a QFP (14 x 14 x 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 thus obtained was subjected to moisture absorption treatment at 85 ° C, 85% for 24 hours, and then immersed in a solder bath at 240 ° C for 1 minute. After that, the surface of the package was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0027]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulation device of the present invention have excellent moisture resistance and solder heat resistance, are less affected by moisture absorption, and are not affected by electrode corrosion. It is possible to remarkably reduce the generation of leakage current due to disconnection and moisture, and it is possible to guarantee the reliability for a long period of time.

Claims (2)

[Claims] (A) an epoxy resin represented by the following general formula: (B) A dicyclopentadiene / phenolic polymer represented by the following general formula: (In the formula, R represents a C _m H _{2m + 1} group, and m, n are 0 or 1
Each of the above integers is represented.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the inorganic filler of (C) is contained in a proportion of 25 to 95% by weight with respect to the entire resin composition. An epoxy resin composition comprising: (A) an epoxy resin represented by the following general formula: (B) a dicyclopentadiene / phenolic polymer represented by the following general formula: (In the formula, R represents a C _m H _{2m + 1} group, and m, n are 0 or 1
Each of the above integers is represented.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the inorganic filler of (C) is contained in a proportion of 25 to 95% by weight with respect to the entire resin composition. A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with a cured product of the contained epoxy resin composition.