JPH06220165A - Epoxy resin composition and encapsulated semiconductor device - Google Patents

Abstract

PURPOSE:To provide the subject composition containing a phenylphenolic novolak epoxy resin, a novolak epoxy resin and an inorganic filler as essential components at specific ratios and excellent in moisture resistance and soldering heat resistance. CONSTITUTION:The objective composition contains, as essential components, (A) a phenylphenolic novolak epoxy resin (e.g. o-phenylphenolic novolak epoxy resin), (B) a novolak phenolic resin obtained by reacting a phenol such as an alkylphenol with formaldehyde or paraformaldehyde [as for the compounding ratio, the molar ratio (epoxy group of component A/ phenolic hydroxy group of component B) is preferably 0.1-10] and (C) an inorganic filler (preferably silica particle having an average particle diameter of <=30mum) at a ratio of 25-90wt.% based on a resin composition. In the objective encapsulated semiconductor device semiconductor elements are encapsulated by the hardened resin of the 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 conventional semiconductor device sealed with a resin composition consisting of an epoxy resin such as a phenol novolac type epoxy resin and a cresol novolac type epoxy resin, a novolac type phenolic resin and silica powder is used for the entire device. The immersion in the solder bath has 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 element, or between the encapsulating resin and the lead frame, and internal resin cracks cause significant deterioration in moisture resistance, which may cause wire breakage or moisture due to electrode corrosion. A leak current is generated, and as a result, the semiconductor device has a drawback 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, is particularly excellent in moisture resistance and solder heat resistance after immersion in a solder bath, and has a sealing resin and a semiconductor element or sealing. 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 object, the present inventors have found that by using a specific epoxy resin together with a novolac type phenolic resin, moisture resistance and solder heat resistance can be improved. It was found that an excellent resin composition can be obtained, and the present invention has been completed.

That is, the present invention comprises (A) phenylphenol novolac type epoxy resin, (B) novolac type phenolic resin and (C) inorganic filler as essential components,
The inorganic filler (C) is added to the resin composition in an amount of 25 to 90.
The epoxy resin composition is characterized in that it is contained in a weight percentage. A semiconductor encapsulation device is obtained by encapsulating a semiconductor element with a cured product of this epoxy resin composition.

The present invention will be described in detail below.

The (A) phenylphenol novolak type epoxy resin used in the present invention may be any one in which the hydrogen atom of the phenolic hydroxyl group in phenylphenol novolac is replaced with a glycidyl group, and the molecular weight and the like are particularly limited. Can be used without.
For example, an o-phenylphenol novolac type epoxy resin represented by Chemical formula 1 and a p-phenylphenol novolac type epoxy resin represented by Chemical formula 2 can be mentioned.

[0009]

[Chemical 1]

[0010]

[Chemical 2] These epoxy resins can be used alone or in combination of two or more. In addition to these phenylphenol novolac type epoxy resins, phenol or cresol novolac type epoxy resins and epibis type epoxy resins can be used in combination.

The novolak type phenolic resin (B) used in the present invention is a novolak type phenolic resin obtained by reacting phenols such as phenol and alkylphenol with formaldehyde or paraformaldehyde, and modified resins thereof such as epoxidized or Butylated novolac type phenolic resin and the like can be mentioned, and these can be used alone or in combination of two or more kinds. The mixing ratio of the novolac type phenol resin is such that the epoxy group (a) of the epoxy resin of (A) and the phenolic hydroxyl group (b) of the novolac type phenol resin of (B) are
It is desirable that the molar ratio [(a) / (b)] with () is 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, 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 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 specific epoxy resin, novolac type phenolic resin and inorganic filler as essential components, but within the range not deviating from the object of the present invention, and if necessary, 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, etc. A curing accelerator, 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, novolac type phenol resin, inorganic filler and other components, and mix well with a mixer or the like. After uniformly mixing, a melt mixing process using a hot roll or a mixing process using a kneader or the like is further performed, and then the mixture is cooled and solidified and 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 elements 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 element using the above molding material. Examples of the semiconductor element to be sealed include integrated circuits, large-scale integrated circuits, transistors,
The thyristor and the diode are not particularly limited. 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.

[0016]

In the epoxy resin composition and semiconductor encapsulation device of the present invention, the glass transition temperature of the resin composition is increased by using a specific epoxy resin or novolac type phenol resin, and the thermomechanical properties and low stress And the occurrence of resin cracks after solder dipping and solder reflow,
The moisture resistance is less deteriorated.

[0017]

EXAMPLES The present invention will now be described in detail 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 18% o-phenylphenol novolac type epoxy resin represented by the following formula (epoxy equivalent 250),

[0019]

[Chemical 3] Novolak type phenolic resin 7%, silica powder 74%, curing accelerator 0.4%, ester waxes 0.3% and silane coupling agent 0.3% are mixed at room temperature and then 90-95%.
After kneading and cooling at 0 ° C., it was pulverized to produce a molding material (A).

Example 2 19% of p-phenylphenol novolac type epoxy resin (epoxy equivalent 330) represented by the following formula:

[0021]

[Chemical 4] Novolak type phenolic resin 6%, silica powder 74%, hardening accelerator 0.4%, ester waxes 0.3% and silane coupling agent 0.3% are mixed at room temperature and then 90-95%.
After kneading and cooling at 0 ° C., it was pulverized to produce a molding material (B).

Example 3 9% of o-phenylphenol novolac type epoxy resin (epoxy equivalent of 250) used in Example 1, 8% of o-cresol novolac type epoxy resin, 8% of novolac type phenol resin, 74% of silica powder, Curing accelerator 0.4%, ester waxes 0.3% and silane coupling agent 0.3%
Was mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (C).

Comparative Example 1 o-Cresol Novolac Novolac 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% at room temperature, and
After kneading and cooling at 90 to 95 ° C., it was pulverized to produce a molding material (D).

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% were used at room temperature. And mix at 90-95 ℃
After kneading and cooling with, the mixture was pulverized to produce a molding material (E).

Molding materials (A) to (E) thus produced
Was used for transfer injection into a mold heated to 170 ° C., and the semiconductor element 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
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.

[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. A resin composition comprising (A) phenylphenol novolac type epoxy resin, (B) novolac type phenolic resin and (C) inorganic filler as essential components, and 25% of the inorganic filler of (C) to the resin composition. An epoxy resin composition, characterized in that it is contained in a proportion of from 90 to 90% by weight. 2. A phenylphenol novolac type epoxy resin (A), a novolac type phenolic resin (B) and an inorganic filler (C) are essential components, and the inorganic filler of (C) is added to the resin composition in an amount of 25. A semiconductor encapsulation device, wherein a semiconductor element is encapsulated with a cured product of an epoxy resin composition contained in a proportion of ˜90 wt%.