JPH0673154A - Epoxy resin composition and sealed semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the subject composition, comprising prescribed amounts of a specific epoxy resin, a specified phenolic resin and a specific inorganic filler, excellent in moisture and solder heat resistance without causing cracks and useful as sealed semiconductor devices, etc. CONSTITUTION:The objective composition comprises (A) an epoxy resin expressed by formula I [R<1> is CjH2j+1; R<2> is CkH2k+1; R<3> is ClH2l+1; R<4> is CmH2m+1; (j), (k), (l), (m) and (n) are 0 or 1], (B) a phenolic resin expressed by formula II (R<5> is CjH2j+1; R<6> is CkH2k+1; R<7> is ClH2l+1; (j), (k), (l) and (n) are 0 or 1) and (C) an inorganic filler such as silica powder as essential components. The component (C) is contained in an amount of 25-90wt.% based on the 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 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 a flat package type semiconductor device is attached to a circuit board, soldering is conventionally 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 device or between the encapsulation resin and the lead frame, or internal resin cracking causes 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, 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 to achieve the above-mentioned object, the present invention shows that moisture resistance and solder heat resistance can be improved by using a combination of a specific epoxy resin and a specific phenol resin. 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]

[Chemical 5] (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l and m and n in each group are
0 or an integer of 1 or more) (B) a phenol resin represented by the following general formula and

[0008]

[Chemical 6] (However, in the formula, R ⁵ is a C _j H _{2j + 1} group and R ⁶ is a C _k H _{2k + 1 group.}
Group, R ⁷ is a C _l H _{2l + 1} group a each represent, j in each group, k and l and n represents 0 or an integer of 1 or more) (C) an inorganic filler as essential components, the resin composition The epoxy resin composition is characterized by containing the inorganic filler (C) in a proportion of 25 to 90% by weight with respect to the product. 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 it can be used without being limited by its molecular weight and the like. As a specific compound, for example,

[0011]

[Chemical 7]

[0012]

[Chemical 8]

[0013]

[Chemical 9] (However, in the formulas of Chemical formulas 7 to 9, n represents 0 or an integer of 1 or more) and the like, and these can be used alone or in combination. 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 (B) phenol resin used in the present invention, the phenol resin represented by the above general formula 6 can be used. As a specific compound, for example,

[0015]

[Chemical 10]

[0016]

[Chemical 11] (However, in the formulas of Chemical formulas 10 and 11, n represents 0 or an integer of 1 or more) and the like, and these can be used alone or in combination. In addition to this 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.

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 preferable to mix them so as to contain them by weight. 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, specific phenol resin and inorganic filler as essential components, but to the extent that the purpose of the present invention is not impaired, and if necessary, For example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, paraffins and other release agents, antimony trioxide and other flame retardants, carbon black and other colorants, and silane coupling agents. Various curing accelerators, rubber-based or silicone-based low stress imparting agents, 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 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. 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. As a semiconductor device for sealing,
For example, an integrated circuit, a large-scale integrated circuit, a transistor, a thyristor, a diode, etc. are not particularly limited.
The most general 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 molding material, heat and cure,
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.

[0021]

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 the above-mentioned specific epoxy resin and specific phenol resin, and the thermomechanical properties and low The stress resistance is improved, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and the deterioration of moisture resistance is reduced.

[0022]

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 Epoxy resin 17% shown in Chemical formula 7, Phenolic resin 8% shown in Chemical formula 11, Silica powder 74%, Curing accelerator 0.3%, Ester waxes 0.3% 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 (A).

Example 2 18% of the epoxy resin shown in Chemical formula 7, 3.5% of the phenolic resin shown in Chemical formula 11, 3.5% of novolac type phenolic resin,
74% of silica powder, 0.3% of hardening accelerator, 0.3% of ester waxes and 0.4% of silane coupling agent were mixed at room temperature, further kneaded 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
0.3%, 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 18% of epoxy resin shown in Chemical formula 7, 7% of novolak type phenolic resin, 74% 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 and inject into a mold heated to 170 ° C., and cured to seal a semiconductor element to manufacture a semiconductor sealing device. Various tests were performed 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, It was possible to confirm the remarkable effect of the present invention.

[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 in advance at 40 ° C., 95% RH for 100 hours, 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 1.4 m
m) The product was placed in a package, transfer molded at 175 ° C for 2 minutes using the molding material, and then post-cured 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 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): (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l and m and n in each group are
0 or an integer of 1 or more) (B) A phenolic resin represented by the following general formula and (However, in the formula, R ⁵ is a C _j H _{2j + 1} group and R ⁶ is a C _k H _{2k + 1 group.}
Group, R ⁷ is a C _l H _{2l + 1} group a each represent, j in each group, k and l and n represents 0 or an integer of 1 or more) (C) an inorganic filler as essential components, the resin composition An epoxy resin composition comprising the inorganic filler of (C) in an amount of 25 to 90% by weight based on the amount of the epoxy resin composition. 2. An epoxy resin represented by the following general formula (A): (However, in the formula, R ¹ is a C _j H _{2j + 1} group, and R ² is C _k H _{2k + 1.}
R ³ represents a C ₁ H _{2l + 1} group, R ⁴ represents a C _m H _{2m + 1} group, and j, k, l and m and n in each group are
0 or an integer of 1 or more) (B) A phenol resin represented by the following general formula and (However, in the formula, R ⁵ is a C _j H _{2j + 1} group and R ⁶ is a C _k H _{2k + 1 group.}
Group, R ⁷ is a C _l H _{2l + 1} group a each represent, j in each group, k and l and n represents 0 or an integer of 1 or more) (C) an inorganic filler as essential components, the resin composition A semiconductor encapsulation device, wherein 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 with respect to the product.