JPH06220166A - Epoxy resin composition and encapsulated semiconductor device - Google Patents

Abstract

PURPOSE:To provide the subject composition containing of a specific novolak epoxy resin, phenolic resin and inorganic filler as essential components at specific ratios, excellent in moisture resistance and soldering heat resistance and useful for encapsulating electric parts, etc. CONSTITUTION:The objective composition contains, as essential components, (A) an epoxy resin of formula I (R<1> is CjH2j+1; R<2> is CkH2k+1; R<3> is C1H21+1; R<4> is CmH2m+1; j, k, l, m and n are 0 and >=1), (B) a phenolic resin of formula II (R<5> is CjH2j+1; R<6> is CkH2k+1; j, k and n are 0 and >=1) and (C) an inorganic filler (preferably silica powder having an average particle diameter of <=30mum) at a ratio of 25-90wt.% based on the total 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]

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 encapsulation resin and the semiconductor device, or between the encapsulation resin and the lead frame, and internal resin cracks cause significant deterioration in moisture resistance, causing disconnection and moisture due to electrode corrosion. Leakage current due to
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 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]

[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.}
Group, 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 in each group and n in the formula are an integer of 0 or 1 or more. (B) a phenolic 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.}
And each group represents j and k, and n in the formula represents 0 or an integer of 1 or more.) (C) The inorganic filler is an essential component, and the inorganic filler of (C) is added to the resin composition. It is an epoxy resin composition characterized by containing 25 to 90% by weight. A semiconductor encapsulation device is obtained by encapsulating a semiconductor device 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 is used, and the epoxy resin can be used without being limited by its molecular weight and the like. As a specific compound, for example,

[0011]

[Chemical 7] (However, in the formula, n represents 0 or an integer of 1 or more),

[0012]

[Chemical 8] (Wherein 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,

[0014]

[Chemical 9] (However, in the formula, n represents 0 or an integer of 1 or more.) Further, this phenol resin is a novolac type phenol resin obtained by reacting phenols such as phenol and alkylphenols with formaldehyde or paraformaldehyde, and modified products thereof. A resin can be used together.

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 phenolic resin and inorganic filler as essential components, but within a 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, 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 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 crushed 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 the semiconductor device using the above-mentioned molding material. Examples of the semiconductor device for sealing 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.

[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 specific epoxy resin and the specific phenol resin, and the thermomechanical characteristics and the low stress property are obtained. Is improved, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and moisture resistance deterioration 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 Epoxy resin 10% shown in the following Chemical formula 10,

[0022]

[Chemical 10] (However, in the formula, n represents 0 or an integer of 1 or more.)
Phenolic resin 8% shown in 1,

[0023]

[Chemical 11] (However, in the formula, n represents 0 or an integer of 1 or more.) Silica powder 81%, curing accelerator 0.3%, ester waxes 0.3%
And 0.4% of the 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 (A).

Example 2 11% epoxy resin of Chemical formula 10 and phenolic resin of Chemical formula 11
3.5%, novolac type phenolic resin 3.5%, silica powder 81%, hardening 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 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 Epibis type epoxy resin (epoxy equivalent 450) 20%, novolac type phenol resin 5%, silica powder 74%, curing accelerator 0.3%, ester waxes 0.3% and silane coupling agent 0.4% were used 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
A semiconductor encapsulation device was manufactured by injecting transfer into a mold heated to 170 ° C., encapsulating the semiconductor device and curing it. 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
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, a silicon chip with two or more aluminum wires is bonded to a normal 42 alloy frame and transfer molded 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.

[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.}
Group, 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 in each group and n in the formula are an integer of 0 or 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.}
And each group represents j and k, and n in the formula represents 0 or an integer of 1 or more.) (C) The inorganic filler is an essential component, and the inorganic filler of (C) is added to the resin composition. An epoxy resin composition characterized by containing 25 to 90% by weight. 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.}
Group, 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 in each group and n in the formula are an integer of 0 or 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.}
And each group represents j and k, and n in the formula represents 0 or an integer of 1 or more.) (C) The inorganic filler is an essential component, and the inorganic filler of (C) is added to the resin composition. A semiconductor encapsulation device, which is obtained by encapsulating a semiconductor device with a cured product of an epoxy resin composition containing 25 to 90% by weight of.