JPH06220167A - Epoxy resin composition and encapsulated semiconductor device - Google Patents

Abstract

PURPOSE:To provide the subject composition composed of a specific resin and an inorganic filler at a specific ratio, excellent in moisture resistance, soldering heat resistance, corrosion resistance and mechanical properties such as crack resistance and useful for producing an encapsulated semiconductor device in an integrated circuit, etc. CONSTITUTION:The objective composition contains (A) a an epoxy resin such as an aromatic epoxy resin and an aliphatic epoxy resin having a cyclohexane derivative, (B) a novolak phenolic resin having a structure obtained by the condensation of o-phenylphenol or p-phenylphenol and (C) an inorganic filler such as silica particle having an average particle diameter of <=30mum, etc., at a ratio of 25-90wt.% based on the total resin composition (component A+B+ C=l00wt.%). As for the compounding ratio of component A and B in the objective composition, the molar ratio (epoxy group of component A/phenolic hydroxy group of component B) is 0.1-10. In the objective encapsulated semiconductor device semiconductor chips are preferably encapsulated by the hardened resin of the objective composition.

Description

Detailed Description of the Invention

[0001]

The present invention relates to moisture resistance, solder heat resistance,
The present invention relates to an epoxy resin composition having excellent moldability and a semiconductor sealing 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. 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 after solder bath immersion, solder heat resistance and moldability, and a sealing resin and a semiconductor chip. Alternatively, the epoxy resin composition and the semiconductor encapsulation device can ensure long-term reliability without peeling of the encapsulation resin from the lead frame or generation of internal resin cracks, disconnection due to electrode corrosion, or leakage current due to moisture. Is to provide.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving the above object, the present inventors have found that by using an epoxy resin or a specific phenol resin, moisture resistance, solder heat resistance, and moldability are improved. It was found that an excellent resin composition can be obtained, and the present invention has been completed.

That is, the present invention relates to (A) epoxy resin,
(B) A novolac-type phenol resin having a skeleton condensed with o-phenylphenol or p-phenylphenol and (C) an inorganic filler are essential components, and the inorganic filler of (C) above is added to the resin composition. The epoxy resin composition is characterized by being contained in a proportion of from 90 to 90% by weight. Further, by the cured product of this epoxy resin composition,
A semiconductor encapsulation device characterized in that a semiconductor chip is encapsulated.

The present invention will be described in detail below.

As the epoxy resin (A) used in the present invention, as long as it is a compound having at least two epoxy groups in its molecule, the molecular structure, molecular weight and the like are not particularly limited, and generally used as a sealing material. It is possible to broadly include what has been done. Examples thereof include bisphenol-type aromatic resins, aliphatic resins such as cyclohexane derivatives, and epoxy novolac resins represented by the following general formula.

[0009]

[Chemical 1] (In the formula, R ¹ represents a hydrogen atom, a halogen atom or an alkyl group, R ² represents a hydrogen atom or an alkyl group, and n represents an integer of 1 or more.) These epoxy resins may be used alone or in combination of two or more. Can be used.

Examples of the (B) novolac type phenolic resin (hereinafter referred to as novolac type phenylphenolic resin) having a skeleton condensed with o-phenylphenol or p-phenylphenol used in the present invention include:
Those having a skeletal structure represented by the formula can be used.

[0011]

[Chemical 2] (However, in the formula, n represents 0 or an integer of 1 or more)

[0012]

[Chemical 3] (In the formula, n represents 0 or an integer of 1 or more.) These can be used alone or in combination of two or more.

In addition to the phenol resin, 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 compounding ratio of the novolac type phenylphenol resin is such that the epoxy group (a
) To the phenolic hydroxyl group (b) of the novolac type phenylphenol resin of (B) [(a) / (b
)] Is preferably within the range of 0.1 to 10. When the molar ratio is less than 0.1 or more than 10, the heat resistance, moisture resistance, molding workability and electrical properties of the cured product deteriorate, which is not preferable.

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 moldability are poor, which is not preferable. The blending ratio of the inorganic filler is 25 to 90 with respect to the entire resin composition.
It is desirable to formulate so as to contain the composition in a weight percentage. When the proportion is less than 25% by weight, the hygroscopicity of the resin composition is high and the moisture resistance after solder immersion is poor, and when it exceeds 90% by weight, the fluidity is extremely deteriorated and the moldability is poor, which is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned epoxy resin, a specific phenol resin and an inorganic filler as essential components. However, as long as it does not deviate from the object of the present invention, and if necessary, it may be, for example, natural. Waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, release agents such as paraffin, flame retardants such as antimony trioxide, colorants such as carbon black, silane coupling agents, various curing Accelerators, rubber-based and silicone-based low stress imparting agents and the like can be added and blended appropriately.

A general method for preparing the epoxy resin composition of the present invention as a molding material is to mix the above-mentioned epoxy resin, a specific phenol resin, an inorganic filler and other components, and homogenize them sufficiently with a mixer or the like. After the mixing, the mixture can be melt-mixed with a hot roll or mixed with a kneader, and then cooled and solidified to be pulverized to an appropriate size to obtain a molding material. If the molding material thus obtained is applied to sealing, coating, insulation, etc. of electronic components such as semiconductor chips or electrical components, 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]

In the epoxy resin composition and the semiconductor encapsulation device of the present invention, the glass transition temperature of the resin composition is increased by using the epoxy resin and the specific phenol resin.
Thermo-mechanical properties and low stress properties are improved, resin cracks are not generated after solder immersion and solder reflow, and moisture resistance deterioration is reduced.

[0020]

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% o-cresol novolac epoxy resin, 9% o-phenylphenol resin shown in Chemical formula 4,

[0022]

[Chemical 4] (However, in the formula, n represents 0 or an integer of 1 or more.) Silica powder 74%, curing accelerator 0.4%, ester waxes 0.3%
Further, 0.3% of a 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 (A).

Example 2 16% o-cresol novolac epoxy resin, 9% p-phenylphenol resin shown in Chemical formula 5,

[0024]

[Chemical 5] (However, in the formula, n represents 0 or an integer of 1 or more.) Silica powder 74%, curing accelerator 0.4%, ester waxes 0.3%
And 0.3% 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 phenolic resin 8%, silica powder 74%, curing accelerator
0.4%, ester waxes 0.3% and silane coupling agent 0.3% 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 Epibis type epoxy resin (epoxy equivalent 450) 20%, novolac type phenol resin 5%, silica powder 74%, curing accelerator 0.4%, ester waxes 0.3% and silane coupling agent 0.3% at room temperature. And mix at 90-95 ℃
After kneading and cooling with, the mixture was pulverized to produce a molding material (D).

Molding materials (A) to (D) thus produced
Transfer injection was carried out into a mold heated to 170 ° C. by using, 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.

[0028]

[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 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 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: 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. Then, the package surface was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0029]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulating device of the present invention are excellent in moisture resistance, solder heat resistance and moldability, are less affected by moisture absorption, It is possible to remarkably reduce the disconnection due to corrosion and the generation of leak current due to moisture, and it is possible to guarantee the reliability for a long period of time.

Claims (2)

[Claims] 1. A resin composition comprising (A) an epoxy resin, (B) a novolac-type phenol resin having a skeleton condensed with o-phenylphenol or p-phenylphenol, and (C) an inorganic filler as essential components. An epoxy resin composition comprising the inorganic filler (C) in an amount of 25 to 90% by weight. 2. A resin composition comprising (A) an epoxy resin, (B) a novolak type phenol resin having a skeleton condensed with o-phenylphenol or p-phenylphenol, and (C) an inorganic filler as essential components. A semiconductor encapsulation device in which a semiconductor chip is encapsulated with a cured product of an epoxy resin composition containing the inorganic filler (C) in a proportion of 25 to 90% by weight.