JP3512460B2 - Epoxy resin composition and semiconductor encapsulation device - Google Patents

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 fluidity and solder heat resistance, and a semiconductor encapsulation device in which a semiconductor chip is encapsulated 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 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 comprising an epoxy resin containing 2% or more of a monomer such as a novolac type epoxy resin, a novolac type phenol resin and silica powder has excellent fluidity. However, there is a drawback that the heat resistance is remarkably lowered, and the moisture resistance is lowered when the whole device is immersed in a solder bath. In particular, when a semiconductor device that has absorbed moisture is immersed, peeling between the encapsulating resin and the semiconductor chip, or the encapsulating resin and the lead frame, and internal resin cracks cause significant deterioration in moisture resistance, causing wire breakage and moisture due to electrode corrosion. As a result, there is a drawback that a semiconductor device 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, fluidity and solder heat resistance after immersion in a solder bath, and has a sealing resin and a semiconductor chip. Alternatively, an epoxy resin composition and a semiconductor encapsulation that can ensure long-term reliability without peeling between the encapsulation resin and the lead frame, internal resin cracks, wire breakage due to electrode corrosion, and leakage current due to moisture are not generated. It is intended to provide a stop device.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a resin composition excellent in moisture resistance, solder heat resistance and the like can be obtained by using a specific epoxy resin. The present invention has been completed 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] (In the formula, R ¹ represents a t-butyl group, R ² represents a methyl group, R ³ represents a C ₁ H _{2l + 1} group, and R ⁴ represents a C _m H _{2m + 1} group. l, m and n represent 0 or an integer of 1 or more.) (B) Phenol resin represented by the following general formula

[Chemical 6] (C) Inorganic filler (D) A curing accelerator as an essential component, and the above (C) with respect to the entire resin composition.
The epoxy resin composition is characterized by containing 25 to 95% by weight of the inorganic filler. Also,
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 3 is used. Further, this epoxy resin can be used without being limited by its molecular weight or the like. As a specific compound, for example,

[0010]

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

[0011]

[Chemical 8] (However, in the formula, n represents 0 or an integer of 1 or more) and the like. These can be used alone or in combination.
Further, as the epoxy resin, a novolac-based epoxy resin, a biphenyl-based epoxy resin, and other known epoxy resins can be used in combination.

Examples of the (B) phenol resin used in the present invention include those having a skeleton structure represented by the following formula.

[0013]

[Chemical 9] (However, in the formula, n represents 0 or an integer of 1 or more)

[0014]

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. . Average particle size 30 μm
When it exceeds, the moldability is deteriorated, which is not preferable. The blending ratio of the inorganic filler is preferably 25 to 90% by weight based on the total resin composition. 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 becomes extremely poor and the moldability is poor, which is not preferable.

As the curing accelerator (D) used in the present invention, a phosphorus curing accelerator, an imidazole curing accelerator, D
A wide range of BU-based curing accelerators and other curing accelerators can be used. These may be used alone or in combination of two or more. The mixing ratio of the curing accelerator is preferably 0.01 to 5% by weight based on the total resin composition. If the proportion is less than 0.01% by weight, the gel time of the resin composition is long and the curing properties are poor, and if it exceeds 5% by weight, the fluidity is extremely poor and the moldability is poor, and the electrical properties are also poor. It is inferior in moisture resistance and is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, phenol resin, inorganic filler and curing accelerator as essential components. For example, natural waxes, synthetic waxes, metal salts of straight chain fatty acids, acid amides, esters, release agents such as paraffins, flame retardants such as antimony trioxide, colorants such as carbon black,
A silane coupling agent, 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, phenol resin, inorganic filler, curing accelerator and other components, and mix with a mixer or the like. After sufficiently homogeneously mixing, a melt mixing process using a hot roll or a kneading process is further performed, followed by cooling and solidifying and pulverizing 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-mentioned 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 the curing by heating, it is desirable to heat and cure at 150 ° C. or higher.

[0020]

The epoxy resin composition and the semiconductor encapsulation device of the present invention, even if the epoxy resin contains 2 to 5% of a monomer by using a specific epoxy resin or phenol resin, The glass transition temperature of the resin composition is increased, the mechanical properties and low stress properties are improved, the occurrence of resin cracks after solder immersion and solder reflow is eliminated, and deterioration of moisture resistance is reduced.

[0021]

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 10% of an epoxy resin (weight average n = 1.5) having the structure of the above Chemical Formula 7 and containing 5% of the monomer, and the phenolic resin of the above Chemical Formula 9 (BRG manufactured by Showa High Polymer Co., Ltd.) −
556) 5%, fused silica powder 84%, hardening accelerator (triphenylphosphine) 0.3%, ester wax (carnauba wax) 0.3% and silane coupling agent (Nippon Unicar A-187). 4% was mixed at room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (A).

[0023] 5% with having the same structure of Formula 7 as used in Comparative Example 1 Example 1
Epoxy resin containing monomers (weight average n = 1.
5) 10.2%, the following general formula

[Chemical 10] In phenol resin represented (Meiwa Kasei MEH-75
0) 4.8%, o-cresol novolac type epoxy resin (ESCN-195XL manufactured by Sumitomo Chemical Co., Ltd.) 8%, fused silica powder 76%, curing accelerator (triphenylphosphine)
0.3%, ester wax (carnauba wax) 0.
3% and 0.4% of a silane coupling agent (A-187 manufactured by Nippon Unicar Co., Ltd.) were mixed at room temperature, and 90 to 9 was further added.
After kneading and cooling at 5 ° C., it was pulverized to produce a molding material (B).

[0024] Comparative Example 2 Example 1 has the same structure of Formula 7 and using an epoxy resin with a reduced monomer content to 1% (weight average n = 1.
5) 10%, novolac type phenol resin (BRG-556 manufactured by Showa Highpolymer Co., Ltd.) 5%, fused silica powder 84%, curing accelerator (triphenylphosphine) 0.3%, ester wax (carnauba wax) 0.3 % And a silane coupling agent (A-187 manufactured by Nippon Unicar Co., Ltd.) 0.4
% At room temperature, further kneaded and cooled at 90 to 95 ° C., and then pulverized to produce a molding material (C).

[0025] Comparative Example 3 Example 1 has the same structure of Formula 7 and using an epoxy resin with a reduced monomer content to 1% (weight average n = 1.
5) 10.2%, 4.8% of the phenol resin of Chemical formula 10 used in Comparative Example 1 (MEH-750 manufactured by Meiwa Kasei Co., Ltd.), 84% of fused silica powder, 0.3% of curing accelerator (triphenylphosphine). , Ester wax (Carnauba wax)
0.3% and a silane coupling agent (A-187 manufactured by Nippon Unicar Co., Ltd.) 0.4% are mixed at room temperature, and then 90-
After kneading and cooling at 95 ° C., it was pulverized to produce a molding material (D).

Molding materials (A) to (D) thus produced
Was used for transfer injection into a mold heated to 170 ° C., 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 have the same moisture resistance and solder as those of the epoxy resin containing less monomer. Since it has heat resistance and shows better fluidity than the epoxy resin containing less monomer, the remarkable effect of the present invention can be confirmed.

[0027]

[Table 1] * 1: A molded product having a diameter of 50 mm and a thickness of 3 mm was prepared by transfer molding, and the molded product was allowed to stand in saturated steam at 127 ° C. and 2.5 atmospheric pressure for 24 hours and measured by the increased weight. * 2: Make a molded product similar to the case of water absorption, 175 ℃,
After post-curing for 8 hours, a test piece having 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 wirings is bonded to a normal 42 alloy frame, transfer molded at 175 ° C for 2 minutes, and then post-cured at 175 ° C for 8 hours. went. The molded product thus obtained was previously subjected to moisture absorption treatment at 40 ° C., 90% RH for 100 hours, and then immersed in a solder bath at 250 ° C. for 10 seconds. Then, PCT was carried out in saturated steam at 127 ° C. and 2.5 atm, and 50% disconnection due to corrosion of aluminum was evaluated as defective. * 5: The 8x8mm dummy chip is replaced by a QFP (14x14x
1.4mm) 17)
After transfer molding at 5 ° C for 2 minutes, 175 ° C at 8
Post-curing was performed for a period of time. The semiconductor encapsulation device thus obtained was subjected to moisture absorption treatment at 85 ° C., 85% for 24 hours, and then at 240 ° C.
It was immersed in the solder bath for 1 minute. Then, the package surface was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0028]

As is clear from the above description and Table 1, the epoxy resin composition and the semiconductor encapsulation device of the present invention use an epoxy resin containing 2 to 5% of a monomer, Excellent in fluidity, moisture resistance and solder heat resistance,
The influence of moisture absorption is small, disconnection due to corrosion of electrodes and generation of leak current due to moisture can be significantly reduced, and reliability can be guaranteed for a long period of time.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08G 59/00-59/72 H01L 23/29 H01L 23/31

Claims (2)

(57) [Claims] 1. An epoxy resin represented by the following general formula (A) in which the content of a monomer in which n is 0 is 2 to 5% : (However, in the formula, R ¹ is a t-butyl group, R ² is a methyl group, R ³ is a C ₁ H _{2l + 1} group, and R ⁴ is a C _m H _{2m + 1.}
Represents a group, and l, m and n in each group are 0
Alternatively, it represents an integer of 1 or more. ) (B) Phenolic resin represented by the following general formula : (C) Inorganic filler (D) A curing accelerator as an essential component, and the above (C) with respect to the entire resin composition.
An epoxy resin composition comprising the inorganic filler of 25 to 90% by weight. 2. (A) An epoxy resin represented by the following general formula, in which the content of a monomer in which n is 0 is 2 to 5% : (However, in the formula, R ¹ is a t-butyl group, R ² is a methyl group, R ³ is a C ₁ H _{2l + 1} group, and R ⁴ is a C _m H _{2m + 1.}
Represents a group, and l, m and n in each group are 0
Alternatively, it represents an integer of 1 or more. ) (B) Phenolic resin represented by the following general formula : (C) Inorganic filler (D) A curing accelerator as an essential component, and the above (C) with respect to the entire resin composition.
A semiconductor encapsulation device, which is obtained by encapsulating a semiconductor chip with a cured product of an epoxy resin composition containing the inorganic filler in a proportion of 25 to 90% by weight.