JPH083277A - Epoxy resin composition and sealed semiconductor device - Google Patents

Abstract

PURPOSE:To provide a sealed semiconductor device having high reliability in immersion in a solder by using a sealing material comprising a specific epoxy resin, a specific phenolic resin, an inorganic filler, and a curing accelerator as essential components. CONSTITUTION:A blend of an epoxy resin (A) represented by formula I and a phenolic resin (B) represented by formula II (wherein (n) is 0 or a larger number) is mixed with 25-95wt.% inorganic filler (C) and a curing accelerator (D) to produce a sealing resin. An example of the resin (B) is the one represented by formula III. The filler (C) is preferably a silica powder having an average particle diameter of 30mum or smaller. The sealed semiconductor device is obtained by applying the sealing resin to a semiconductor chip and thermally curing the resin. The cured resin does not develop cracks through immersion in a solder or solder reflowing and is reduced in deterioration caused by moisture.

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]

A semiconductor device sealed with a conventional resin composition comprising an epoxy resin such as a novolac type epoxy resin, a novolac type phenolic resin and silica powder has a moisture resistance when the entire device is immersed in a solder bath. There was a drawback that the property deteriorated. In particular, when a semiconductor device that has absorbed moisture is dipped, peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and internal resin cracking cause significant deterioration in moisture resistance, causing disconnection and moisture due to electrode corrosion. As a result, there is a drawback that a semiconductor device 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 between resin and lead frame, generation of internal resin cracks, disconnection due to electrode corrosion and leakage current due to moisture. It is the one we are trying to provide.

[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 phenol resin,
It was found that a resin composition excellent in moisture resistance, solder heat resistance, etc. can be obtained, and the present invention has been completed.

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

[0007]

Embedded image (B) a phenolic resin represented by the following general formula,

[0008]

[Chemical 6] (However, in the formula, n represents 0 or an integer of 1 or more) (C) The inorganic filler and (D) the curing accelerator are essential components, and the inorganic filler of the above (C) is added to the entire resin composition. Is contained in a proportion of 25 to 95% 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 epoxy resin represented by the above general formula 5 is used. Further, a novolac-based epoxy resin, an epibis-based epoxy resin, a biphenyl-based epoxy resin, and other known epoxy resins can be used in combination with this epoxy resin.

As the (B) 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 by its molecular weight and the like. As a specific compound, for example,

[0012]

[Chemical 7]

[0013]

Embedded image Etc., and these can be used alone or in combination. Further, a novolak 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 with this phenol resin.

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 95 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 a high hygroscopicity and is inferior in moisture resistance after solder immersion, and if it exceeds 95% by weight, the fluidity is extremely poor and the 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
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 kinds. 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.

The semiconductor encapsulation device of the present invention can be easily manufactured by encapsulating a semiconductor chip using the above 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.

[0019]

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]

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 8.9% of the above-mentioned epoxy resin of Chemical formula 5, 8.1% 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, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (A).

Example 2 The same epoxy resin of Chemical formula 5 used in Example 1 (4.7%), the phenol resin of Chemical formula 7 used in Example 1 (4.3%), silica powder 90%, curing accelerator 0.3%, ester waxes 0.3 %
And 0.4% of a silane coupling agent were mixed at room temperature, further 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, further 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).

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.

[0026]

[Table 1] * 1: Diameter 50 mm, thickness 3 mm by transfer molding
A molded article of the above was prepared, and the molded article was allowed to stand 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., 95% 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: QFP (14 × 14 × 1.4m) with 8 × 8mm dummy chip
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 24 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.

[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] 1. An epoxy resin represented by the following general formula (A): (B) A phenolic resin represented by the following general formula: (However, in the formula, n represents 0 or an integer of 1 or more) (C) The inorganic filler and (D) the curing accelerator are essential components, and the inorganic filler of the above (C) is added to the entire resin composition. 25 to 95% by weight of the epoxy resin composition. 2. An epoxy resin represented by the following general formula (A): (B) A phenolic resin represented by the following general formula: (However, in the formula, n represents 0 or an integer of 1 or more) (C) The inorganic filler and (D) the curing accelerator are essential components, and the inorganic filler of the above (C) is added to the entire resin composition. A semiconductor encapsulation device, wherein a semiconductor chip is encapsulated with a cured product of an epoxy resin composition containing 25 to 95% by weight of.