JPH08319341A - Epoxy resin composition for sealing and semiconductor device using the same - Google Patents

Abstract

PURPOSE: To provide an epoxy resin composition for sealing, small in the coefficients of linear expansion of molded products, large in thermal conductivity, well maintaining moisture resistance reliability and little in abrasion, and further to provide a semiconductor device using the same. CONSTITUTION: The epoxy resin composition for sealing contains an inorganic filler in an amount of 50-90 wt.% based on the whole amount of the sealing epoxy resin composition. Therein, the inorganic filler contains at least one kind selected from the group of talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and cordierite, and the content of at least one kind of impurity selected from the group of Cl<-> , NO3 <-> , SO4 <2-> , Na<+> , NH4 <+> and K<+> is <=50ppm based on the whole amount of the inorganic filler. The epoxy resin composition for sealing can be used for sealing semiconductor elements loaded on lead frames.

Description

Detailed Description of the Invention

[0001]

The present invention relates to electric parts, electronic parts,
The present invention relates to a sealing epoxy resin composition for sealing semiconductor elements and the like and a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, a package having a small thermal resistance has been demanded in order to improve the reliability of power devices such as power ICs and power transistors. In the case of the full-mold type package of MyCares specification, the thickness of the molded resin product that covers the heat dissipation part of the lead frame tends to become thinner in order to improve heat dissipation and reduce thermal resistance. . Further, in order to improve the heat dissipation property, a sealing epoxy resin composition containing high thermal conductivity crystalline silica so as to be filled as high as possible is used.

However, since crystalline silica has a high abrasion property, the epoxy resin composition for encapsulation which uses crystalline silica as the inorganic filler easily abrades the manufacturing apparatus and the molding die, and the manufacturing apparatus and the molding die. There is a problem that the life of the mold is shortened.

On the other hand, a method of reducing the coefficient of linear expansion of a molded article by using fused silica having a low coefficient of linear expansion and a low coefficient of moisture absorption and improving the moisture resistance reliability has been investigated. However, in the case of an encapsulating epoxy resin composition using fused silica, the heat conductivity is low, so the heat dissipation is poor, and the wear resistance is smaller than that of crystalline silica, but further low wear resistance is required. Has been. Further, in the case of an epoxy resin composition for sealing which has small wear resistance, for example, an inorganic filler such as wollastonite, the content of impure ions is large, and this epoxy resin composition for sealing is used. The conventional semiconductor device has a problem that it is inferior in moisture resistance reliability.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to obtain a molded product having a small linear expansion coefficient, a large thermal conductivity, and a moisture resistance reliability. An object of the present invention is to provide an encapsulating epoxy resin composition that maintains good satisfactorily and has a small wear resistance, and a semiconductor device using the same.

[0006]

The epoxy resin composition for encapsulation according to claim 1 of the present invention is an epoxy resin, a curing agent,
A curing accelerator and an inorganic filler are contained, and the content of the inorganic filler is 50 with respect to the total amount of the epoxy resin composition for sealing.
In the encapsulating epoxy resin composition, which is ˜90 wt%, the inorganic filler is selected from the group of talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and cordierite. Cl ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , Na ⁺ , NH containing at least one kind and contained in the inorganic filler.
The content of at least one impurity ion selected from the group of ₄ ⁺ and K ⁺ is 50 ppm with respect to the total amount of the inorganic filler.
It is characterized by the following.

In the epoxy resin composition for encapsulation according to claim 2 of the present invention, the inorganic filler is 1000 to 1400 ° C.
Talc, enstatite, petalite, β-spodumene, wollastonite,
It is characterized by containing at least one selected from the group of anorthite, kaolin, mullite and cordierite.

The epoxy resin composition for encapsulation according to claim 3 of the present invention is characterized in that the anorthite is a baked product obtained by baking a mixed product of kaolin and calcium carbonate.

According to a fourth aspect of the present invention, a semiconductor element mounted on a lead frame is sealed by using the epoxy resin composition for sealing according to any one of the first to third aspects. It is characterized by stopping.

The present invention will be described in detail below. The epoxy resin used in the present invention is an epoxy resin having at least two epoxy groups in one molecule, and includes, for example, cresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, Triphenol methane type epoxy resin,
An epoxy resin such as a biphenyl type epoxy resin, an epoxy resin having a naphthalene ring, a brom-containing epoxy resin, and a glycidyl ester type epoxy resin can be exemplified. The epoxy resin used in the present invention is not particularly limited, but one having a low melt viscosity is preferable. For example, a bifunctional or trifunctional epoxy resin having a biphenyl skeleton or a naphthalene skeleton in the basic skeleton of the resin is used. be able to.

The curing agent used in the present invention is not particularly limited, and a phenol type curing agent, an amine type curing agent, an acid anhydride curing agent and the like can be used, but the epoxy resin composition has a small moisture absorption rate and high reliability. For this purpose, it is desirable to use a phenolic curing agent having two or more phenolic hydroxyl groups in the molecule and having a low melt viscosity, and examples thereof include phenol novolac resin, cresol novolac resin and polyfunctional phenol resin.

In the present invention, as the curing accelerator, for example, triphenylphosphine and its derivative, imidazole and its derivative, diazabicycloundecene, tetraphenylphosphonium, tetraphenylborate, and 3 are used.
A primary amine or the like can be used.

The epoxy resin composition for encapsulation according to the present invention contains carnauba wax, if necessary, in addition to the above-mentioned components.
A release agent such as stearic acid, a flame retardant such as brominated epoxy resin and antimony trioxide, a pigment such as carbon black, a coupling agent such as epoxysilane, and the like may be added. In the case of adding a coupling agent, it is also possible to use the one in which only the inorganic filler is surface-treated in advance with the coupling agent.

The content of the inorganic filler used in the present invention must be 50 to 90% by weight based on the total amount of the epoxy resin composition for sealing. Furthermore, this inorganic filler contains talc, enstatite, petalite, β-spodumene,
At least one selected from the group of wollastonite, anorthite, kaolin, mullite and cordierite is 25% by weight or more, preferably 50% by weight or more, more preferably 75% by weight, based on the total amount of the inorganic filler. As described above, more preferably 90% by weight or more, and Cl ⁻ , NO ₃ ⁻ , SO contained in the inorganic filler is required.
It is essential that the content of at least one impurity ion selected from the group of ₄ ²⁻ , Na ⁺ , NH ₄ ⁺ and K ⁺ is 50 ppm or less with respect to the total amount of the inorganic filler. This makes it possible to obtain an epoxy resin composition for encapsulation which has a small linear expansion coefficient, a large thermal conductivity, a good moisture resistance reliability, and a small abrasion resistance of the obtained molded product. That is, when the content of the impure ions exceeds 50 ppm with respect to the total amount of the inorganic filler, the moisture resistance reliability of the obtained molded product is deteriorated.

Examples of the method for adjusting the content of the impure ions in the inorganic filler to 50 ppm or less with respect to the total amount of the inorganic filler include firing and boiling. This inorganic filler
It is preferable to contain at least one selected from the group consisting of talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and cordierite, which has been heat-treated at 1000 to 1400 ° C. for 30 minutes or more. The inorganic filler heat-treated at 1000 to 1400 ° C. for 30 minutes or more has an impure ion content of 50 ppm or less with respect to the total amount of the inorganic filler, and the resulting molded article has excellent moisture resistance reliability and a crystalline structure. Changes and the coefficient of linear expansion tends to decrease. Examples of the inorganic filler whose crystal structure changes by firing include talc, kaolin and petalite. That is, talc changes to enstatite at about 1000 ° C, kaolin changes to mullite at about 1100 ° C, and petalite changes to β-spodumene at about 950 to 1080 ° C.

When the firing temperature is lower than 1000 ° C., the content of impurity ions in the inorganic filler tends to exceed 50 ppm with respect to the total amount of the inorganic filler, and the firing temperature is 140 ° C.
If the temperature exceeds 0 ° C., a special baking furnace is required, and the inorganic filler is melted and needs to be pulverized again.

The anorthite is kaolin and calcium carbonate.
It is preferable that it is a fired product obtained by firing a mixture with um.
Yes. That is, anorthite (CaO ・ Al₂O₃・ 2
SiO ₂), Kaolin (Al₂O₃・ 2SiO₂・ 2
H₂O) and calcium carbonate (CaCO₃) And burn
When it is formed and produced, the reactivity is high, so 1300
It can be produced at a relatively low firing temperature of about ℃,
For example, Al₂O₃, SiO₂, CaCO₃And so on,
If it is produced by firing, raise the firing temperature further.
Has to be done and a lot of energy is needed.
U

In this way, the above materials are blended, mixed,
The epoxy resin composition for encapsulation is obtained by kneading, pulverizing and, if necessary, granulating.

Further, the epoxy resin composition for sealing is molded by a transfer molding machine or the like.

A semiconductor device according to the present invention is obtained by encapsulating a semiconductor element mounted on a lead frame using the epoxy resin composition and has a small linear expansion coefficient and a large thermal conductivity. , Excellent in moisture resistance reliability.

[0021]

The epoxy resin composition for encapsulation according to claim 1 of the present invention contains an epoxy resin, a curing agent, a curing accelerator and an inorganic filler, and the content of the inorganic filler is the epoxy resin for encapsulation. In the epoxy resin composition for encapsulation which is 50 to 90% by weight with respect to the total amount of the composition, the inorganic filler is
At least one selected from the group consisting of talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and cordierite, and Cl ⁻ contained in the inorganic filler, NO.
_Since the content of at least one impurity ion selected from the group of ₃ ⁻ , SO ₄ ²⁻ , Na ⁺ , NH ₄ ⁺ and K ⁺ is 50 ppm or less based on the total amount of the inorganic filler, the coefficient of linear expansion is Is small, the thermal conductivity is large, the moisture resistance reliability is good, and the abrasion resistance is small.

In the epoxy resin composition for encapsulation according to claim 2 of the present invention, the inorganic filler is 1000 to 1400 ° C.
Talc, enstatite, petalite, β-spodumene, wollastonite,
Since it contains at least one selected from the group of anorthite, kaolin, mullite and cordierite, the content of impure ions is 50 ppm or less with respect to the total amount of the inorganic filler, and the resulting molded article has high moisture resistance reliability. In addition to being excellent, the crystal structure changes and the coefficient of linear expansion becomes small.

The epoxy resin composition for encapsulation according to claim 3 of the present invention has a high reactivity because the anorthite is a baked product obtained by baking a mixed product of kaolin and calcium carbonate, and therefore has a high reactivity. Can be produced at a relatively low firing temperature.

A semiconductor device according to a fourth aspect of the present invention uses the epoxy resin composition for sealing according to any one of the first to third aspects to seal a semiconductor device mounted on a lead frame. Since it is stopped, the coefficient of linear expansion is small, the thermal conductivity is large, and the humidity resistance is excellent.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples.

(Examples 1 to 4 and Comparative Examples 1 to 3) The following raw materials were used in the blending amounts shown in Table 1. As an epoxy resin, an ortho-cresol novolac type epoxy resin having an epoxy equivalent of 195 (manufactured by Sumitomo Chemical Co., Ltd .;
Part number ESCN195 XL-3) is used as a curing agent, and phenol novolac resin having a hydroxyl equivalent of 104 and a melting point of 82 ° C. (manufactured by Arakawa Chemical Industry Co., Ltd .; product name Tamanol 752) is used.
As the curing accelerator, 1,8-diaza-bicyclo (5,5
4,0) undecene-7 (hereinafter referred to as DBU), γ-glycidoxypropyltrimethoxysilane as a coupling agent, carnauba wax as a release agent, carbon black as a colorant, Brominated epoxy resin and antimony trioxide were used as the flame retardant.

As the inorganic filler, in Example 1, an inorganic filler obtained by firing talc at 1200 ° C. for 3 hours (the crystal structure changed to enstatite), and in Example 2, petalite was used. Inorganic filler obtained by firing at 1300 ° C. for 3 hours (the crystal structure is changed to β-spodumene), and in Example 3, wollastonite was 1000
An inorganic filler obtained by firing at 5 ° C. for 5 hours was used. Example 4
The inorganic filler used in (1) was mixed at a ratio of 20 parts by weight of calcium carbonate (manufactured by Nitto Koka Co., Ltd .; product number NS # 100) with 80 parts by weight of New Zealand kaolin manufactured by Kyoritsu Kiln Raw Materials Co., Ltd., and the mixture was heated at 200 ° C./hour. Raise the temperature to 1300 ° C and
After baking at 300 ° C for 30 minutes, cooling to room temperature at 150 ° C / hour, crushing with a ball mill, and average particle size of 10 μm
I used the anorthite. As the inorganic filler used in Comparative Examples, crystalline silica was used in Comparative Example 1, fused silica was used in Comparative Example 2, and unburned wollastonite that was not heat-treated was used in Comparative Example 3.

An inorganic filler obtained by adding a coupling agent at a ratio of 0.7 part by weight of γ-glycidoxypropyltrimethoxysilane to 100 parts by weight of the inorganic filler and coupling the mixture was used. And used in Comparative Examples.

In each of the above Examples and Comparative Examples, the blended components were uniformly mixed and dispersed in a mixer for 3 minutes, and then heated, melted and kneaded with a mixing roll having a roll temperature of 100 ° C. The kneaded product was cooled and pulverized to obtain an epoxy resin composition for sealing.

Further, each of the sealing epoxy resin compositions was sealed and molded with a transfer molding machine at a mold temperature of 180 ° C. and a molding pressure of 50 kg / cm ² . Further, a molded product for each evaluation was also obtained.

Abrasion resistance, linear expansion coefficient, thermal conductivity and moisture resistance reliability were measured using each of the sealing epoxy resin compositions and molded products obtained above, and the results are shown in the evaluation column of Table 1. It was

Further, in Table 1, impurity ions Cl ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , Na ⁺ , which are contained in the inorganic filler,
Each content of NH ₄ ⁺ and K ⁺ and showed total content of these impurities ions.

[0033]

[Table 1]

The measured values shown in Table 1 were obtained by the following method. (1) Content of Impurity Ions The content of impure ions in the extract treated with each inorganic filler in pure water at 100 ° C. for 20 hours was measured using ion chromatography to determine the impurity content with respect to the total amount of the inorganic fillers. The content of ions is shown in ppm.

(2) Abrasivity Using a transfer molding machine, mold temperature 150 ° C.
Input pressure 70 kg / cm ², Infusion time 10-13 seconds, 4
Transfer of 0 g of each epoxy resin composition for sealing
And a die made of aluminum with the orifice 2 shown in FIG.
1 through the molten epoxy resin composition for sealing, 6
The weight loss of the aluminum mold after 0 shot is g (Grass)
). (3) Using a transfer molding machine with a linear expansion coefficient of 75 tons, mold temperature 1
Molded at 80 ℃ for 60 seconds, diameter 4mm, length 30
mm test piece was prepared and heated by TMA at 5 ° C / min.
The value at speed was measured. (4) Thermal conductivity Rapid thermal conductivity meter (Showa Denko KK; trade name QTM-D2)
Was measured using. (5) Moisture resistance reliability A comb-shaped aluminum wiring circuit with a line width of 3 μm is provided.
8mm x 17mm x 0.4mm with lath protective film
42-inch semiconductor chip (evaluation semiconductor element)
Mounted on a lead frame made of Roy using silver paste
This semiconductor chip is then
Use a 26-pin SOP molding die under the above conditions.
Sealed with the epoxy resin composition for sealing of Examples and Comparative Examples.
Stop-molding and post-curing were performed to obtain a sample for evaluation. Profit
Evaluation sump in which the evaluated semiconductor element is sealed
Moisture for 72 hours at 85 ° C and 85% RH, then 2
It was immersed in a solder bath at 50 ° C. for 10 seconds. Next PCT 2
20V of 20V under the condition of pressure (121 ℃, 100% RH)
A continuous energization test for 0 hours was performed. Finished this electrification test
Check the resistance value of the sample, and change it from the initial value before the test.
The one in which the resistance value changed was regarded as defective. Ie 2
Open circuit failure (circuit break) of aluminum circuit after 00 hours
The presence or absence was observed, and the obtained results are shown in Table 1 (number of defectives) /
It is shown as (total number of samples tested).

As shown in Table 1, according to the present invention as in Examples 1 to 4, compared with Comparative Examples 1 to 3, the molded products have a smaller linear expansion coefficient, a higher thermal conductivity and a higher humidity resistance. It was confirmed that the epoxy resin composition for encapsulation, which maintains good reliability and has low abrasion resistance, can be obtained. Even when kaolin or cordierite heat-treated at 1000 to 1400 ° C. for 30 minutes or more was used as the inorganic filler, substantially the same effect as that of the example was obtained.

[0037]

According to the epoxy resin composition for encapsulation according to claim 1 of the present invention, the inorganic filler is talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and koji. Cl ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ containing at least one selected from the group of lights and contained in the inorganic filler,
Since the content of at least one impurity ion selected from the group of Na ⁺ , NH ₄ ⁺ and K ⁺ is 50 ppm or less with respect to the total amount of the inorganic filler, the linear expansion coefficient is small and the thermal conductivity is large. A molded product having good moisture resistance and low wear resistance can be obtained.

According to the encapsulating epoxy resin composition of claim 2 of the present invention, the inorganic filler is 1000 to 14
Contain at least one selected from the group consisting of talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin, mullite and cordierite that has been heat-treated at 00 ° C for 30 minutes or more. The amount becomes 50 ppm or less with respect to the total amount of the inorganic filler, the obtained molded article has excellent moisture resistance reliability, and the crystal structure changes to obtain a molded article having a small linear expansion coefficient.

According to the encapsulating epoxy resin composition of claim 3 of the present invention, since the anorthite is a calcined product obtained by calcining a mixture of kaolin and calcium carbonate, the reactivity is high, and thus 1300 ° C. Energy can be saved because it can be produced at a relatively low firing temperature.

According to a fourth aspect of the present invention, there is provided a semiconductor element mounted on a lead frame using the encapsulating epoxy resin composition according to any one of the first to third aspects. Since it is sealed, the coefficient of linear expansion is small, the thermal conductivity is large, the humidity resistance is good, and the wear resistance is small.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an orifice used for measuring abrasion resistance of an epoxy resin composition for sealing according to an example of the present invention.

[Explanation of symbols]

 1 Aluminum mold 2 Orifice

Claims (4)

[Claims] 1. A seal containing an epoxy resin, a curing agent, a curing accelerator and an inorganic filler, the content of the inorganic filler being 50 to 90% by weight based on the total amount of the epoxy resin composition for sealing. In the epoxy resin composition for stopping, the inorganic filler is talc, enstatite, petalite, β-spodumene, wollastonite, anorthite, kaolin,
C contained in the inorganic filler, containing at least one selected from the group of mullite and cordierite
l ⁻ , NO ₃ ⁻ , SO ₄ ²⁻ , Na ⁺ , NH ₄ ⁺ and K ⁺
The epoxy resin composition for encapsulation, wherein the content of at least one impurity ion selected from the group is 50 ppm or less based on the total amount of the inorganic filler. 2. The inorganic filler is 1000 to 1400.
Talc, enstatite, petalite, β-spodumene, wollastonite, heat treated at 30 ° C for 30 minutes or more
The epoxy resin composition for encapsulation according to claim 1, comprising at least one selected from the group consisting of anorthite, kaolin, mullite and cordierite. 3. The epoxy resin composition for encapsulation according to claim 1, wherein the anorthite is a baked product obtained by baking a mixed product of kaolin and calcium carbonate. 4. A semiconductor element, which is mounted on a lead frame, is encapsulated with the epoxy resin composition for encapsulation according to any one of claims 1 to 3. apparatus.