JPH08134182A - Epoxy resin composition and semiconductor sealing device - Google Patents

Abstract

PURPOSE: To obtain the subject composition excellent in moisture resistance, soldering heat resistance, etc., useful for sealing semiconductor chips, etc., essentially comprising a specific epoxy resin, specific phenolic resin, inorganic filler and curing promoter. CONSTITUTION: This composition essentially comprises (A) an epoxy resin of formula I (R<1> is a Cm H2m+1 group; R<2> is a Cn H2n+1 group; (m) and (n) are each integer, 0 or >=1) (e.g. a compound of formula III), (B) a dicyclopentadiene- modified phenolic resin of formula II (R<3> is a Cj H2j+1 group; (j) and (n) are each integer, 0 or >=1) (e.g. a compound of formula IV), (C) 25-93wt.% of an inorganic filler (pref. silica powder <=30μm in average particle diameter with low impurity content), and (D) pref. 0.01-5wt.% of a curing promoter (e.g. phosporus-, imidazole-, DBU-based one).

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 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 technology development for high integration and high reliability, automation of the mounting process of semiconductor devices is being promoted. For example, when mounting a flat package type semiconductor device on a circuit board, conventionally, soldering is performed for each lead pin, but recently, a solder dipping method or a solder reflow method has been adopted.

[0003]

Conventionally, a semiconductor device sealed with a resin composition consisting of an epoxy resin such as a novolac type epoxy resin, a novolac type phenolic resin and silica powder has a moisture resistance when the whole device is immersed in a solder bath. There was a drawback that the property deteriorated. Especially when a semiconductor device that has absorbed moisture is immersed, peeling between the encapsulation resin and the semiconductor chip, or the encapsulation resin and the lead frame, and internal resin cracks cause significant deterioration in moisture resistance, which may be caused by wire breakage or moisture due to electrode corrosion. Leakage current, resulting in
The semiconductor device has a drawback in that it cannot guarantee long-term reliability.

The present invention has been made in order to solve the above-mentioned drawbacks, has little influence of moisture absorption, and is particularly excellent in moisture resistance and solder heat resistance after being immersed in a solder bath. Epoxy resin composition and semiconductor encapsulation device capable of ensuring long-term reliability without peeling of resin and lead frame or generation of internal resin cracks, disconnection due to electrode corrosion or leakage current due to moisture It is what

[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 by using a specific epoxy resin and a specific phenol resin, moisture resistance, solder heat resistance, etc. can be improved. 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 (However, in the formula, R ¹ is a C _m H _{2m + 1} group and R ² is a C _n H group.
_{2n + 1} group respectively, m and n in each group are 0 or 1
Representing the above integers) (B) Dicyclopentadiene-modified phenol resin represented by the following general formula

[0008]

[Chemical 6] (However, in the formula, R ³ is a C _j H _{2j + 1} group, and j and n are 0 or
Each represents an integer of 1 or more.) (C) Inorganic filler (D) Curing accelerator is an essential component, and the above (C) is used for the entire resin composition.
An epoxy resin composition containing the inorganic filler of 25 to 93% by weight. 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 one represented by the above general formula 5 is used, and the epoxy resin can be used without any particular limitation on its molecular weight and the like. As a specific compound, for example,

[0011]

[Chemical 7]

[0012]

Embedded image

[0013]

[Chemical 9] And the like. These can be used alone or in combination of two or more. In addition, a novolac type epoxy resin, a biphenyl type epoxy resin, and other generally known epoxy resins can be used in combination with this epoxy resin.

As the (B) dicyclopentadiene-modified phenol resin used in the present invention, the one represented by the above general formula 6 is used, and it can be used without being particularly limited in its molecular weight and the like. Specific compounds include, for example,

[0015]

[Chemical 10]

[0016]

[Chemical 11] And these can be used alone or in combination. In addition to the dicyclopentadiene-modified phenolic resin, a novolac type phenolic resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde and these modified resins can be used in combination.

As the inorganic filler (C) used in the present invention, those generally used 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 the moldability are deteriorated, which is not preferable. The blending ratio of the inorganic filler is 25 to 93 with respect to the entire resin composition.
It is preferable to mix them so as to contain them by weight. If the proportion is less than 25% by weight, the resin composition has high hygroscopicity and is inferior in moisture resistance after solder dipping, and if it exceeds 93% by weight, fluidity is extremely deteriorated and moldability is inferior, which is not preferable.

As the curing accelerator (D) used in the present invention, a phosphorus curing accelerator, an imidazole curing accelerator, D
BU-based curing accelerators and other curing accelerators are widely used. These may 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, the moldability will be poor, and the electrical characteristics will be poor and the moisture resistance will be poor. It is inferior in sex and 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 linear fatty acids, acid amides, esters, release agents such as paraffin,
A flame retardant such as antimony trioxide, a coloring agent 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. And the like, followed by melt-mixing treatment with a hot roll or mixing treatment with a kneader, and then cooling and solidifying to pulverize 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 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 method of sealing 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. For curing by heating, it is desirable to heat and cure at 150 ° C or higher.

[0022]

The epoxy resin composition and the semiconductor encapsulation device of the present invention reduce the water absorption of the resin composition by using a specific epoxy resin and a specific phenol resin, and have excellent thermomechanical properties and low stress. It is improved, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and the deterioration of moisture resistance is reduced.

[0023]

EXAMPLES 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 6.8% of the above-mentioned epoxy resin of Chemical formula 8, 6.2% of the above-mentioned chemical formula 11 of dicyclopentadiene-modified phenol resin, 86% of silica powder, 0.3% of curing accelerator, ester waxes
0.3% and a silane coupling agent 0.4% were mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (A).

Example 2 3.5% of the epoxy resin of Chemical formula 8 used in Example 1, 3.5% of the biphenyl type epoxy resin, 6.0% of the dicyclopentadiene-modified phenol resin of Chemical formula 11 used in Example 1, 86% of silica powder, 0.3% of hardening accelerator, ester waxes 0.3
% And silane coupling agent 0.4% at room temperature,
After further kneading and cooling at 90 to 95 ° C., the mixture was pulverized to produce a molding material (B).

Comparative Example 1 o-Cresol Novolak type epoxy resin 11.2%, novolac type phenol resin 5.8%, silica powder 82%, curing accelerator 0.3%, ester waxes 0.3% and silane coupling agent 0.4% are mixed at room temperature. After further kneading and cooling at 90 to 95 ° C., the mixture was pulverized to produce a molding material (C).

Comparative Example 2 11.3% of biphenyl type epoxy resin, 5.7% of novolac type phenol resin, 82% of silica powder, 0.3% of curing accelerator,
0.3% of ester waxes and silane coupling agent
0.4% was mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (D).

Molding materials (A) to (D) thus produced
Was used to transfer transfer 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 encapsulation devices, and the results are shown in Table 1. The epoxy resin composition and the semiconductor encapsulation device of the present invention are excellent in moisture resistance and solder heat resistance. The remarkable effect of the invention could be confirmed.

[0029]

[Table 1] * 1: Diameter 50 mm, thickness 3 mm by transfer molding
The molded product of No. 1 was prepared, and it was left in 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 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: Using a molding material, attach a silicon chip with two or more aluminum wirings 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 product thus obtained is subjected to moisture absorption treatment at 40 ° C., 90% RH for 100 hours in advance, and then
It was immersed in a solder bath at 250 ° C for 10 seconds. After that, 127 ℃,
PCT was performed in saturated steam of 2.5 atm and 50% disconnection due to corrosion of aluminum was evaluated as defective. * 5: A dummy chip of 8 x 8 mm is used for QFP (14 x 14 x 1.0 m
m) It was placed in a package, transfer molding was performed for 2 minutes at 175 ° C using the molding material, and then post-curing was performed at 175 ° C for 8 hours. The semiconductor encapsulation device obtained in this way is 85 ℃, 85%,
After absorbing moisture for 96 hours, it was immersed in a solder bath at 240 ° C for 1 minute. After that, observe the package surface with a stereomicroscope,
The occurrence of external resin cracks was evaluated.

[0030]

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.

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Claims (2)

[Claims] 1. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ is a C _m H _{2m + 1} group and R ² is a C _n H group.
_{2n + 1} group respectively, m and n in each group are 0 or 1
(B) represents a dicyclopentadiene-modified phenol resin represented by the following general formula: (However, in the formula, R ³ is a C _j H _{2j + 1} group, and j and n are 0 or
Each represents an integer of 1 or more.) (C) Inorganic filler (D) Curing accelerator is an essential component, and the inorganic filler of (C) is contained in a proportion of 25 to 93% by weight based on the entire resin composition. An epoxy resin composition comprising: 2. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ represents an _m H _{2m + 1} group, R ² represents a C _n H _{2n + 1} group, and m and n in each group represent 0 or an integer of 1 or more.) (B) Next A dicyclopentadiene-modified phenolic resin represented by the general formula: (However, in the formula, R ³ is a C _j H _{2j + 1} group, and j and n are 0 or 1
Each of the above integers is represented.) (C) Inorganic filler (D) Curing accelerator is an essential component, and the inorganic filler of (C) is contained in a proportion of 25 to 93% by weight with respect to the entire resin composition. By the cured product of the epoxy resin composition, which is characterized by
A semiconductor encapsulation device characterized by encapsulating a semiconductor chip.