JPH09188747A - Epoxy resin composition and sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition, excellent in moisture and solder heat resistances, hardly being influenced by moisture absorption and useful for a sealed semiconductor device by using a specific epoxy resin and a specified phenol resin. SOLUTION: This epoxy resin composition consists essentially of (A) an epoxy resin having a diphenylmethane skeleton of formula I, (B) a cyclopentadiene-phenol polymer of formula II [R is a group of the formula Cm H2m+1 ; (m) and (n) are each 0 or an integer of >=1], (C) an inorganic filler (preferably a silica powder having <=30μm average grain diameter) and (D) a curing accelerator, with the proviso that the component (C) is contained in an amount of 25-93wt.% based on the whole resin composition. Moreover, the sealed semiconductor device comprises a semiconductor chip sealed with a cured product of the epoxy resin composition.

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 sealing device in which a semiconductor chip is sealed with the composition.

[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 attached to a circuit board, conventionally, each lead pin has been soldered, but recently, a solder dipping 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 has a drawback that the moisture resistance is lowered when the entire device is immersed in a solder bath. was there. In particular, when a semiconductor device that has absorbed moisture is immersed, peeling between the sealing resin and the semiconductor chip, or between the sealing resin and the lead frame, and internal resin cracks occur, causing significant moisture resistance deterioration. Leakage current occurs, and as a result, the semiconductor device has a disadvantage that long-term reliability cannot be guaranteed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks and has little influence of moisture absorption, and particularly excellent moisture resistance and solder heat resistance after immersion in a solder bath, and a sealing resin. Epoxy resin composition and semiconductor capable of ensuring long-term reliability without peeling between the semiconductor chip or the encapsulating resin and the lead frame and the occurrence of internal resin cracks, and without the occurrence of wire breakage due to electrode corrosion or leak current due to moisture. It is intended to provide a 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 obtained excellent moisture resistance and solder heat resistance by using a specific epoxy resin and a specific phenol resin. It was found that a resin composition having the above properties can be obtained, and the present invention has been completed.

That is, the present invention provides (A) an epoxy resin having a diphenylmethane skeleton represented by the following general formula,

[0007]

Embedded image (B) a cyclopentadiene / phenol polymer represented by the following general formula,

[0008]

[Chemical 6] (However, in the formula, R represents a C _m H _{2m + 1} group, and m and n represent 0 or an integer of 1 or more.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the entire resin is used. An epoxy resin composition comprising the inorganic filler (C) in a proportion of 25 to 93% by weight with respect to the composition. Further, there is provided a semiconductor encapsulation device wherein a semiconductor chip is encapsulated 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 above general formula 5 are used. In addition, a novolac-based epoxy resin, an epibis-based epoxy resin, and other generally known epoxy resins can be used in combination with this epoxy resin.

As the cyclopentadiene / 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. In addition to the cyclopentadiene / phenol polymer, 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.

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 size of 30 μm or less is preferably used. You can 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 preferably 25 to 93% by weight based on the total resin composition.
If the proportion is less than 25% by weight, the resin composition has a large hygroscopicity and is inferior in moisture resistance after immersion in solder, and if it exceeds 93% by weight, the fluidity becomes 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
BU-based curing accelerators and other curing accelerators are widely used. These can be used alone or in combination of two or more. The compounding ratio of the curing accelerator is 0.01% with respect to the resin composition.
It is desirable to mix them so as to contain up to 5% by weight. 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, and the electrical characteristics will also 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 is necessary within the range not deviating from the object of the present invention. Depending on, for example, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, release agents such as paraffins, flame retardants such as antimony trioxide, carbon black,
A coloring agent such as redwood, a silane coupling agent, a rubber-based or silicone-based low-stress imparting agent, and the like can be appropriately added and blended.

As a general method for preparing the epoxy resin composition of the present invention as a molding material, the above-mentioned specific epoxy resin, specific phenol resin, inorganic filler and curing accelerator and other components are prescribed. After mixing the raw material components selected in the composition ratio and mixing them sufficiently uniformly with a mixer or 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 crushing to an appropriate size. It can be 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 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. The molding material is heated and cured at the time of sealing, and finally a semiconductor sealing device sealed with this cured product is obtained. 150 ° C for curing by heating
It is desirable to heat and cure the above.

The epoxy resin composition and the semiconductor encapsulation device of the present invention reduce the water absorption of the resin composition by using the above-mentioned specific epoxy resin and specific phenol resin, and have low thermomechanical properties and low mechanical properties. Improves stress resistance, eliminating resin cracks after solder immersion and solder reflow,
The moisture resistance is less deteriorated.

[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 6.3% of the above-mentioned epoxy resin of the chemical formula 5, 4.7% of the above-mentioned chemical formula 7 of the phenolic resin, 88% of silica powder, 0.3% of the curing accelerator.
%, Ester wax 0.3% and silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and pulverized to produce a molding material (A).

Example 2 6.5% of the epoxy resin of the chemical formula 5 used in Example 1, 6.5%
3.2% of the phenol resin of Chemical formula 7, 1.3% of phenol novolac resin, 88% of silica powder, 0.3% of curing accelerator
%, Ester wax 0.3%, and silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to prepare 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 wax 0.3% and silane coupling agent 0.4% were mixed, further kneaded at 90 to 95 ° C., and cooled and pulverized to produce a molding material (C).

Comparative Example 2 20% of epibis type epoxy resin, 5% of novolac type phenol resin, 74% of silica powder, 0.3% of curing accelerator, 0.3% of ester wax and 0.4% of silane coupling agent were mixed, and further 90-95. The mixture was kneaded at 0 ° C. and cooled and ground to obtain a molding material (D).

The molding materials (A) to (D) thus produced
Was used to transfer and inject into a mold heated to 170 ° C. and cured to seal the semiconductor chip, thereby producing 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 have excellent 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 rate and
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, a silicon chip with two aluminum wirings is bonded to a normal 42 alloy frame and transfer molded at 175 ° C for 2 minutes.
Post-cure was performed at 8 ° C. for 8 hours. The molded article thus obtained was previously subjected to a moisture absorption treatment at 40 ° C., 90% RH and 100 hours,
C. for 10 seconds. After that, a humidity resistance test was conducted in saturated steam at 127 ° C and 2.5 atm to evaluate the time for 50% disconnection (defect occurrence) due to aluminum corrosion. * 5: QFP (14 x 14 x 1.4 m) with 8 x 8 mm dummy chip
m) Package and use molding compound for 2 at 175 ° C
After transfer molding for 1 minute, post-curing was performed at 175 ° C. for 8 hours. The semiconductor encapsulation device manufactured in this way is
After absorbing moisture for 85% for 24 hours, put it in a solder bath at 240 ℃ 1
Soak for minutes. 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 less susceptible to electrode corrosion. It is possible to remarkably reduce the occurrence of leakage current due to disconnection and moisture, and it is possible to guarantee the reliability for a long time.

Claims (2)

[Claims] 1. (A) An epoxy resin having a diphenylmethane skeleton represented by the following general formula: (B) Cyclopentadiene / phenolic polymer represented by the following general formula: (However, in the formula, R represents a C _m H _{2m + 1} group, and m and n represent 0 or an integer of 1 or more.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the entire resin is used. An epoxy resin composition comprising the inorganic filler (C) in a proportion of 25 to 93% by weight based on the composition. 2. (A) An epoxy resin having a diphenylmethane skeleton represented by the following general formula: (B) a cyclopentadiene / phenol polymer represented by the following general formula: (However, in the formula, R represents a C _m H _{2m + 1} group, and m and n represent 0 or an integer of 1 or more.) (C) An inorganic filler and (D) a curing accelerator are essential components, and the entire resin is used. 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 93% by weight with respect to the composition. .