JPH06145301A - Epoxy resin composition and semiconductor device sealed therewith - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in humidity and soldering-heat resistances and useful in the production of a sealed semiconductor device by mixing a specified epoxy resin with a naphthol curing agent and an inorganic filler in a specified ratio. CONSTITUTION:The composition consists essentially of an epoxy resin of formula I wherein R<1> is a CjH2j+1 group, and j, k, l, m and n are each 0 or an integer of 1, a naphthol curing agent [e.g. a compound of formula II wherein n is 0 or an integer of 1 or greater], and 25-90wt.%, based on the composition, inorganic filler. A sealed semiconductor device prepared by sealing a semiconductor chip with a cured product of this composition is excellent in humidity and soldering-heat resistances, is lowly affected by absorbed moisture, is markedly reduced in the occurrence of disconnection due to electrode corrosion and leakage current due to moisture, and can retain assured reliability for a long time.

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 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, 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. Especially 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 cracking cause significant moisture resistance deterioration, which may cause wire breakage or moisture due to corrosion of the electrodes. A leak current is generated, and as a result, the semiconductor device has a drawback that it cannot guarantee long-term reliability.

[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 object, the present inventors have found that moisture resistance and solder heat resistance can be improved by using a specific epoxy resin and a curing agent having a naphthol skeleton. It was found that a resin composition having excellent properties 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 3] (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, m and n in each group are 0.
Or (representing an integer of 1 or more) (B) a curing agent having a naphthol skeleton and (C) an inorganic filler as essential components, and 25 to 90% by weight of the (C) inorganic filler with respect to the resin composition. It is an epoxy resin composition characterized by the following. 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, those represented by the above formula are used, and the epoxy resins can be used without any particular limitation on the molecular weight and the like. As a specific compound, for example,

[0010]

[Chemical 4]

[0011]

[Chemical 5]

[0012]

[Chemical 6] And the like. These can be used alone or in combination of two or more. In addition, these epoxy resins,
A novolac type epoxy resin and an epibis type epoxy resin can be used together.

Specific examples of the curing agent (B) having a naphthol skeleton used in the present invention include, for example,

[0014]

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

[0015]

[Chemical 8]

[0016]

[Chemical 9] (However, m and n in the formula represent 0 or an integer of 1 or more) and the like, and these can be used alone or in combination of two or more kinds. Further, 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 by mixing with this resin.

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. You can 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 based on the resin composition.
It is desirable that the content is 25 to 90% by weight. If the proportion is less than 25% by weight, the hygroscopicity of the resin composition is large,
Moisture resistance after immersion in solder is poor, and when it exceeds 90% by weight, fluidity is extremely deteriorated and moldability is poor, which is not preferable.

The epoxy resin composition of the present invention contains the above-mentioned specific epoxy resin, a curing agent having a naphthol skeleton, and an 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, release agents for paraffins, chlorinated paraffins, bromotoluene, hexabromobenzene, antimony trioxide, etc. Fuel, carbon black,
A colorant such as red iron oxide, a silane coupling agent, various curing accelerators, 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, a curing agent having a naphthol skeleton, an inorganic filler, and the like are mixed in a predetermined composition ratio. After blending the selected raw material components and mixing sufficiently evenly with a mixer or the like,
Further, a melt mixing treatment with a hot roll or a mixing treatment with a kneader or the like is performed, followed by cooling and solidification, and pulverization into 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 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 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. 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. Curing by heating is 150 ° C
It is desirable to heat and cure the above.

[0021]

In the epoxy resin composition of the present invention, the glass transition temperature of the resin composition is increased by using the above-mentioned specific epoxy resin and the curing agent having the naphthol skeleton, and the thermomechanical properties 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.

[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 17% of the epoxy resin shown in Chemical formula 10

[0024]

[Chemical 10]

8% of a curing agent having a naphthol skeleton shown in Chemical formula 11

[0026]

[Chemical 11] 74% silica powder, 0.3% hardening accelerator, ester wax
0.3% and a silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to produce a molding material.

Example 2 18% of the epoxy resin of Chemical formula 10 used in Example 1 and Chemical formula 1
3.5% hardener with a naphthol skeleton of 1,
Phenolic resin shown in 2 3.5%,

[0028]

[Chemical 12] 74% silica powder, 0.3% hardening accelerator, ester wax
0.3% and a silane coupling agent 0.4% were mixed at room temperature, further kneaded at 90 to 95 ° C., and cooled and ground to produce a molding material.

Comparative Example 1 Orthocresol Novolac type epoxy resin 17% was mixed with novolac type phenol resin 8%, silica powder 74%, curing accelerator 0.3%, ester wax 0.3% and silane coupling agent 0.4%. A molding material was produced in the same manner as in Example 1.

Comparative Example 2 18% of the epoxy resin of Chemical formula 10 used in Example 1, 7% of novolac type phenolic resin, 74% of silica powder, curing accelerator
0.3%, ester wax 0.3% and silane coupling agent 0.4% were mixed and a molding material was manufactured in the same manner as in Example 1.

Using the molding materials produced in Examples 1 and 2 and Comparative Examples 1 and 2, transfer injection was conducted into a mold heated to 170 ° C. and cured to seal a semiconductor element to seal a semiconductor device. Was manufactured. 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.

[0032]

[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 curing was carried out at 8 ° C for 8 hours. The molded product thus obtained was previously subjected to moisture absorption treatment at 40 ° C., 95% RH for 100 hours, and then subjected to 250
It was soaked in a solder bath at ℃ 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
Soaked for a minute. Then, the package surface was observed with a stereoscopic microscope to evaluate the presence or absence of external resin cracks.

[0033]

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.

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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, m and n in each group are 0.
Or (representing an integer of 1 or more) (B) a curing agent having a naphthol skeleton and (C) an inorganic filler as essential components, and 25 to 90% by weight of the (C) inorganic filler with respect to the resin composition. An epoxy resin composition comprising: 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, m and n in each group are 0.
Or (representing an integer of 1 or more) (B) a curing agent having a naphthol skeleton and (C) an inorganic filler as essential components, and 25 to 90% by weight of the (C) inorganic filler with respect to the resin composition. A semiconductor encapsulation device, characterized in that a semiconductor chip is encapsulated with a cured product of an epoxy resin composition.