JP2853550B2 - Epoxy resin composition, method for producing the same, and semiconductor device using the same - 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 for a sealing material for protecting a semiconductor, a method for producing the same, and a sealing type semiconductor device using the epoxy resin composition for a sealing material.

[0002]

2. Description of the Related Art With the development of a highly information-oriented society and semiconductors, functions given to integrated circuits are increasing, and the degree of integration and operation speed are increasing year by year. This leads to an increase in the size of the semiconductor chip and an increase in power consumption. Therefore, in a resin mold type package (hereinafter, referred to as a semiconductor device), a copper alloy having high thermal conductivity is often used as a lead frame. Since the coefficient of linear expansion is different between the copper alloy and the 42 alloy, a conventional sealing material for sealing an integrated circuit of a large chip mounted on a lead frame made of a copper alloy is a conventional 42 mm.
Performance different from the sealing material of the integrated circuit mounted on the alloy lead frame is required. Linear expansion coefficient of each material (α
[ppm / ° C]), the copper alloy is 16-18, the 42 alloy is 5-7, and the silicon chip is 3-18.
4. In the case of a lead frame made of 42 alloy, α is small for both the chip and the lead frame.
Investigations have been continued to make the amorphous silica volume content in the sealing material 70% or more. On the other hand, in the case of a lead frame made of a copper alloy, if the α of the cured product of the sealing material is reduced to about 42 alloys, the difference in thermal expansion between the cured product of the sealing material and the lead frame increases, and the heat shock test and heat cycle test Since a defect occurs in a test such as a test for checking a defect due to thermal stress, the α of the cured product of the sealing material has to be slightly increased. For this reason, the content of amorphous silica as a filler in the sealing material is generally set to about 70% by volume or less.

On the other hand, surface-mount type thin semiconductor devices have become mainstream in order to increase the mounting density. However, in this surface-mount type semiconductor device, it is considered that the cause is moisture absorption of a cured product of a sealing material. In addition, a defect such as peeling between the cured product of the sealing material and the chip or between the cured product of the sealing material and the lead frame behind the die pad after the soldering process is likely to occur (poor in moisture absorption soldering resistance). In order to solve this problem, it is most effective to use a sealing material having an increased filler content to reduce the moisture absorption of a cured product of the sealing material, and it is desired to realize this measure.

[0004]

The small volume content of the filler in the copper alloy lead frame encapsulant is due to the large amount of the resin component, so that the cured product of the encapsulant obtained has a high moisture absorption rate. Semiconductor device (package)
However, there is a problem that the moisture absorption soldering resistance cannot be improved. This has been an issue that needs to be resolved promptly in recent years, as the semiconductor mounting mode is shifting to the surface mounting type. Further, in the surface mount type semiconductor device, since the thickness of the portion where the sealing material is used is thin, poor filling and voids are apt to occur during molding, and the fluidity of the sealing material is maintained well. It is necessary to improve various characteristics such as the moisture absorption resistance and heat shock resistance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device in which a semiconductor chip mounted on a lead frame made of a copper alloy is sealed and which has resistance to moisture absorption and soldering. To provide an epoxy resin composition capable of improving heat shock properties and a method for producing the same, and to provide a sealed semiconductor device using the epoxy resin composition and having excellent moisture absorption solder resistance and heat shock resistance. It is to be.

[0006]

The present invention relates to an epoxy resin composition comprising an epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator and a filler. A filler which is a mixed powder of one or more inorganic powders (B) having a larger coefficient of linear expansion than amorphous silica, wherein the ratio of the inorganic powder (B) to the total filler is 20 to 60 in terms of true specific gravity. % By volume, a filler containing 5 to 20% by volume in terms of true specific gravity in all fillers of spherical amorphous silica powder having a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ² / g. And the filler has a volume fraction of 7 in a compact obtained by compressing the filler at a pressure that maintains the average particle size.
It is characterized in that a filler of 8% or more is used.

[0007] Further, the invention according to the method for producing an epoxy resin composition is characterized in that an epoxy resin and / or a curing agent which is solid at normal temperature is prepared by adding a weight average particle diameter of less than 1 µm and a specific surface area of 10%.
It is characterized in that pulverization is performed in a state where spherical amorphous silica powder of up to 30 m ² / g is added, and then the mixture is mixed and kneaded with other raw materials.

Further, the invention according to the semiconductor device is described in claim 1.
A semiconductor element mounted on a copper alloy lead frame is sealed using the epoxy resin composition according to any one of claims 1 to 5.

Hereinafter, the present invention will be described in detail. Among the fillers used in the epoxy resin composition for a sealing material, amorphous silica has a coefficient of linear expansion of 0.5 to 0.7 ppm / ° C. and can form a spherical particle shape. It is widely used for the purpose of lowering the moisture absorption and lowering the linear expansion coefficient of a cured product of a sealing material because it can be easily filled into the inside. However, the higher the amount of the amorphous silica, the lower the coefficient of linear expansion of the cured product of the sealing material. In general, the α of the cured product of the sealing material containing 70% by volume or more becomes less than 12 ppm / ° C., The difference from the copper alloy lead frame is widening. Therefore, in the present invention, a volume mixing ratio comprising the amorphous silica powder (A) and one or more inorganic powders (B) having a larger linear expansion coefficient than the amorphous silica, and focusing on the true volume of each powder. Is 80/20 to 4
By using a mixed powder of 0/60 as a filler, the linear expansion coefficient of the cured product of the sealing material is maintained in a preferable range for a copper alloy lead frame even when the filler content is increased. When the volume fraction in terms of the true specific gravity in the total filler of the inorganic powder (B) is less than 20%, the linear expansion coefficient of the cured product becomes low, and when it exceeds 60%, the linear expansion coefficient of the cured product becomes large, Not preferred.

Further, in order to lower the moisture absorption rate of the cured product of the sealing material and to improve the resistance to moisture absorption, it is necessary to highly fill the sealing material with a filler. As the filler capable of being highly filled, it is necessary to minimize the free volume between particles, and this is because the weight average particle diameter is less than 1 μm, and
Spherical amorphous silica having a specific surface area of 10 to 30 m ² / g,
It is blended so as to occupy 5 to 20% by volume in terms of true specific gravity with respect to all the fillers. This can be achieved by using a filler having a volume fraction of 78% or more.

Here, the "filler volume fraction in the compact obtained by compression" will be described. When the true specific gravity of each of the n kinds of fillers (n is an integer of 2 or more) used as the inorganic filler is di, and the compounding weight of each inorganic filler is wi (i is an integer of 1 to n), the entire inorganic filler is The true specific gravity d is a value calculated by the following equation (C).

D = {wi / {(wi / di)} (C) Then, when the filler volume fraction in the compact obtained by compression is represented by P, P is expressed in W grams. It is calculated from the apparent volume V cubic centimeter of a molded product obtained by compressing a certain inorganic filler by the following formula (D).

P = 100 (W / d) / V───── (D) In the present invention, the molding pressure of the compression molding of the inorganic filler performed for measuring the volume fraction P is determined before the compression molding. It is important that the average particle size is a pressure that can be maintained after compression molding. If the molding pressure is too high, the particles of the inorganic filler are broken, the average particle diameter after compression molding is different from the average particle diameter before compression molding, and the measured volume fraction P is A disadvantage arises in that the properties of the inorganic filler in the glass cannot be exhibited. This is because, when any of the inorganic fillers is subjected to an excessively high molding pressure during the compression molding, the particles are destroyed and the resulting molded body approaches a state in which no voids are contained, and the measured volume fraction P Is 100
It is because it becomes asymptotic to%. Therefore, in the present invention, the inorganic filler in the compact obtained by compression molding,
The compression pressure during compression molding should be such that the average particle size of the inorganic filler before compression molding is maintained even after compression molding so that it exists in the same state as the inorganic filler contained in the epoxy resin composition. Limited.

Incidentally, the volume fraction P obtained by a compact molded at the maximum pressure (hereinafter abbreviated as Fmax) within the range of the pressure maintained after compression molding is as follows: , Fmax is always larger than the volume fraction P obtained by the molded body molded below Fmax. That is, when the volume fraction P of the inorganic filler of the molded body molded at less than Fmax is 78% or more, the volume fraction P when the inorganic filler is molded at Fmax is always 78%.
% Or more.

The spherical amorphous silica having a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ² / g has a volume fraction (abbreviated as Vs) of not more than 5% by volume relative to all fillers in terms of true specific gravity. In addition, it is difficult to increase the P to 78% or more, and it is not preferable because burrs at the time of molding the epoxy resin composition increase. When Vs exceeds 20% by volume, the P can be increased to 78% or more. However, since the number of particles in all the fillers becomes too large, the composition which is in a molten state when molding the epoxy resin composition is obtained. It is not preferable because molding defects easily occur, which is considered to be caused by the non-Newtonian or thixotropic properties of the product becoming too large.

The one or more inorganic powders (B) having a larger linear expansion coefficient than the amorphous silica used in the present invention include crystalline silica, glass powder not intentionally containing voids, or particles. Is porous and the surface is non-porous or hollow glass powder. Since crystalline silica has a large coefficient of linear expansion of 5 to 6 ppm / ° C. and a small amount of ionic impurities, it is suitable for the purpose of the present invention for an epoxy resin composition used for a semiconductor encapsulant. Glass beads, which are a kind of glass powder that does not intentionally contain voids inside, can easily increase the linear expansion coefficient of glass by changing the type and amount of components other than SiO ₂ , and can also be spheroidized. Since it is easy, it conforms to the gist of the present invention. In addition, the inside of the particles is porous and the surface is non-porous or hollow glass powder reduces the elastic modulus of the cured product of the epoxy resin composition as compared with glass powder containing no voids inside the particles. This has the effect of reducing the thermal stress generated in the semiconductor device.

In the case where the final epoxy resin composition is applied to encapsulation of a memory element, the filler described above is used to prevent soft errors of the memory element due to α rays, such as uranium and thorium. It is preferable to use a so-called α-ray-free filler having a radioisotope content of at least 1 ppb or less as an α-ray source.

By including the above-mentioned filler in the epoxy resin composition at 70% by volume or more in terms of true specific gravity,
The moisture absorption rate of the cured product of the epoxy resin composition can be reduced to improve the moisture absorption soldering resistance of the semiconductor device using the copper alloy lead frame, and the linear expansion coefficient of the cured product between 50 and 100 ° C. Is set to 12 to 17 ppm / ° C., heat shock resistance, which is a kind of heat stress resistance of a semiconductor device using a copper alloy lead frame, can be enhanced.
In addition, the linear expansion coefficient at 50 to 100 ° C.
It changes depending on the structure and the mixing ratio of the curing agent and the organic substance low elastic modulus imparting agent, and is not determined only by the filler volume fraction in the epoxy resin composition. For example, in the case of a resin having a glass transition temperature (Tg) of less than 100 ° C. of a cured product, a region of a linear expansion coefficient (α ₂ ) after Tg of the resin falls between 50 and 100 ° C. As compared with the case where the resin has a Tg of one hundred and several tens of degrees Celsius, the cured product of the resin composition is 50 to
The coefficient of linear expansion between 100 ° C. becomes large. However, regardless of the characteristics of the resin, the cured product of the epoxy resin composition has a linear expansion coefficient between 50 and 100 ° C. of 12 to 17 ppm.
If it is / ° C, the heat shock resistance can be improved.

The above-mentioned filler is desirably subjected to a surface treatment with a coupling agent in order to strengthen the chemical bond with the resin. In this method, after treating the surface of the powder particles with a coupling agent in advance, it may be kneaded with a resin, or may be kneaded with a filler after mixing the coupling agent into the resin component, a so-called integral blending method. It may be something.

The epoxy resin which is an essential component of the present invention is a compound having two or more epoxy groups in one molecule, for example, a phenol novolak type epoxy resin,
Cresol novolak type epoxy resin, bisphenol A type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene-phenol copolymer type epoxy resin, epoxy resin having at least two epoxy groups bonded to one benzene ring And the like. Examples of the curing agent include a phenol-based curing agent and an amine-based compound, and it is preferable to use a phenol-based curing agent that is effective in reducing the moisture absorption of the cured product. A phenolic curing agent is a compound having two or more phenolic hydroxyl groups in one molecule, such as a phenol novolak resin and its derivative, a cresol novolak resin and its derivative, mono- or dihydroxynaphthalene and its derivative, Examples thereof include a copolymer of pentadiene and phenol, hydroxystyrene and a derivative thereof. As the epoxy resin and the curing agent, those having a low melt viscosity are desirably used from the gist of the present invention in that the filler content is increased to reduce the moisture absorption and the fluidity during molding is maintained well.

Examples of the curing accelerator used in the present invention include triphenylphosphine and its derivatives, derivatives including diazabicycloundecene and its salts, and derivatives including imidazole and its salts. .

Components other than the essential components of the epoxy resin composition of the present invention described above can be used as long as the objects of the present invention are not hindered. For example, waxes for imparting a releasing effect, pigments and dyes as coloring agents, ion trapping agents for capturing impurity ions to improve humidity resistance reliability, and various difficulties for imparting a flame retarding effect. It is a low-stress imparting component typified by an elastomer for reducing the modulus of elasticity or the coefficient of linear expansion, such as a fuel agent.

Further, it has been found that the fluidity of the epoxy resin composition is enhanced by adopting a specific production method when producing the epoxy resin composition. That is, the epoxy resin and / or curing agent which are solid at room temperature,
In the method of pulverizing the whole or a part of the epoxy resin composition necessary to obtain a resin powder, then mixing with other raw materials and the like, kneading and finally producing the epoxy resin composition, When pulverizing the resin and / or the curing agent, the weight average particle diameter is less than 1 μm and the specific surface area is 10 μm.
A production method characterized in that spherical amorphous silica powder of ３０30 m ² / g is added to a resin. In the production of an epoxy resin composition, it is common to pulverize and mix and knead the necessary resin components, but the resin fine powder has a strong tendency to agglomerate or caking, and to be filled with fillers other than the resin fine powder. Most of them become large particles before mixing. Therefore, when the resin component is melted at the time of kneading, it takes in agglomerates formed of nearby fine filler particles to form aggregates due to strong liquid crosslinking such as so-called "dama", and the agglomerates are also formed by kneading. It is not expected to completely disappear. According to the production method of the present invention, a layer of silica particles having a weight average particle diameter of less than 1 μm is formed on the surface of the fine powder of the resin component, whereby the resin fine powder is prevented from agglomerating or caking, and other than the resin component. When mixed with the components, the components are very finely and uniformly dispersed, and the degree of residual filler aggregate after kneading is reduced, thereby improving the fluidity of the epoxy resin composition. In addition, when the spherical amorphous silica powder is added to the epoxy resin and / or the curing agent which is solid at room temperature and pulverized, other resin components such as a curing accelerator may be simultaneously added and pulverized. Absent.

[0024]

EXAMPLES Raw materials used in Examples and Comparative Examples will be described.

The epoxy resin is a biphenyl type epoxy resin [YY-4000, manufactured by Yuka Shell Epoxy Co., Ltd.]
H, epoxy equivalent 190, melting temperature 105 ° C.], and the curing agent is a naphthol-phenol polymer [manufactured by Nippon Kayaku Co., Ltd., product number OCN-7000, hydroxyl equivalent 140,
Melting temperature: 120 ° C.], and triphenylphosphine [manufactured by Hokko Chemical Industry Co., Ltd .;
PP is used), natural carnauba wax is used as the wax, and an epoxy silane coupling agent [manufactured by Nippon Unicar Co., Ltd., product number A-187] is used as the coupling agent.
And carbon black was used as a pigment.

The following were used as the amorphous silica powder (A). Product number FB74 which is a commercially available amorphous silica powder
The following two types of fillers obtained by air classification of [Electric Chemical Industry Co., Ltd., average particle size 26 μm, specific surface area 2.6 m ² / g]. The average particle diameter is 36 μm, the specific surface area is 1.6 m ² / g, and the true specific gravity is 2.2 ° or later. The average particle size is 9 μm, the specific surface area is 2.9 m ² / g, and the true specific gravity is 2.2 ° or later.

The following two types of fillers were used as the amorphous silica powder (A). Spherical amorphous silica manufactured by Tatsumori Co., Ltd., product number SOC2, average particle size 0.5 μm, specific surface area 12 m ² / g, true specific gravity 2.
It is expressed as SOC2 after 2────. Spherical amorphous silica manufactured by Denki Kagaku Kogyo Co., Ltd., part number FB
01, the average particle diameter is 0.1 μm, the specific surface area is 35 m ² / g, and the true specific gravity is 2.2 ° or later.

The following three types of inorganic powder (B) having a larger linear expansion coefficient than amorphous silica were used. Crystal silica manufactured by Tatsumori Co., Ltd., product number 3K, average particle size 27
μm, specific surface area 2 m ² / g, true specific gravity 2.6 ° or more, and 3K. Spherical E glass powder (glass beads) manufactured by Toshiba Barotini Co., Ltd., product number GB731, average particle diameter 30 μm, true specific gravity 2.6 ° or later, represented as GB731. Hollow glass powder (borosilicate glass balloon) manufactured by Toshiba Barotini Co., Ltd., product number HSC110, average particle diameter 10 μm, and true specific gravity 1.1 ° or more are represented as HSC110.

Next, the mixed filler used in each example and each comparative example will be described. The raw material fillers were collected at the weights shown in Tables 1 and 2 below, and mixed and dispersed by a rotary mixer to obtain mixed fillers. The mixed filler volume fraction P in the compact obtained by compressing the obtained mixed filler was measured, and the results are shown in Tables 1 and 2. The mixed filler volume fraction P in the compact obtained by compressing the mixed filler was determined as follows. The mixed filler having a weight of W grams is uniaxially pressed at a compression pressure of 300 kg / cm ² to obtain a cylindrical molded body, and the apparent volume V of the molded body calculated from the diameter and thickness of the obtained molded body and the above Of the filler and the true specific gravity d of the entire filler were calculated by the above-described equation (D) to obtain the mixed filler volume fraction P in the molded body. Then, the obtained molded body is crushed, the average particle diameter of the mixed filler after compression molding is measured, and compared with the average particle diameter of the mixed filler used for molding before molding. It was determined whether the particle size was maintained. As a result, in the mixed filler used in each of the examples and the comparative examples, the average particle size was maintained even in the obtained molded body, and at a compression pressure of 300 kg / cm ² , the particles were not broken by compression molding. confirmed.

[0030]

[Table 1]

[0031]

[Table 2]

(Examples 1 to 8 and Comparative Examples 1 to 7) Encapsulation of Examples 1 to 8 and Comparative Examples 1 to 7 using the mixed fillers (F1 to F13) shown in Tables 1 and 2. An epoxy resin composition for a material was prepared. The mixing ratio of the epoxy resin composition was as shown in Tables 3, 4 and 5, and the required amount of the coupling agent was sprayed on the mixed fillers (F1 to F13), dispersed and mixed by a mixer in advance, and then the other components were mixed. Mixed with the raw materials. The kneading of the blend of the raw materials was performed for 6 minutes using a mixing roll at 90 ° C., and the obtained sheet was cooled to room temperature and then pulverized to obtain an epoxy resin composition for a sealing material.

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

Various properties of the obtained epoxy resin composition for a sealing material, a cured product obtained using the epoxy resin composition and a semiconductor device were evaluated as follows. (1) Gel time: The gel time of each epoxy resin composition at 175 ° C. was measured using a Curastometer V type manufactured by Orientec. (2) Coefficient of linear expansion of cured product: Using a special mold, transfer molding at 175 ° C. was performed to obtain a cylindrical molded product of 5 mmφ × 20 mm, and after-curing was performed at 175 ° C. for 6 hours, followed by polishing. The bottom surface and the top surface were parallelized to prepare a test piece for measuring the coefficient of linear expansion. About the test piece, TAS20 manufactured by Rigaku Denki Co., Ltd.
The linear expansion coefficient (α ₁ ) between 50 ° C. and 100 ° C. was measured with a 0-type TMA device. (3) Moisture absorption soldering resistance: 4 × 12 × 0.4 mm CMOS
The element was mounted on a lead frame made of a copper alloy (manufactured by Mitsubishi Electric Corporation, part number MF202) with silver paste, bonded with gold wires, and then used an epoxy resin composition for a sealing material to have an outer dimension of 8.9 × 17.4 x 2.7mm 26SO
Transfer molding was performed using a P package mold. The molding conditions were a temperature of 175 ° C., an injection time of 12 seconds, and a pressing time of 90
The injection was performed for 70 seconds at an injection pressure of 70 kg / cm ² . The obtained molded product was after-cured at 175 ° C. for 6 hours to obtain 26SOP (semiconductor device) for performance evaluation. After leaving the obtained semiconductor device in an atmosphere of a temperature of 85 ° C. and a relative humidity of 85% for 72 hours, it is immersed in a solder bath at 260 ° C. for 10 seconds to seal the back surface of the die pad portion of the copper alloy lead frame inside the semiconductor device. Ultrasonic probe [Canon Co., Ltd., product number M-700II]
Observation was made, and a sample in which a portion in the peeling mode occurred was regarded as defective. In addition, the outside of the semiconductor device was observed with a stereoscopic microscope, and those having cracks were regarded as defective. (4) Heat shock resistance: 26SOP (semiconductor device) for performance evaluation was obtained in the same manner as in the case of moisture absorption and solder resistance.
This semiconductor device is placed in a liquid phase at -65 ° C for 5 minutes to + 150 ° C5.
The heat shock test was repeated for one minute, and after the tests of the number of cycles shown in Tables 6, 7 and 8 were completed, the copper alloy lead frame inside the semiconductor device was treated in the same manner as in the case of the moisture absorption solder resistance. The state of adhesion at the interface between the back surface of the die pad portion and the cured product of the sealing material and the occurrence of external cracks in the semiconductor device were evaluated. (5) Molding defect rate: In the same manner as in the case of moisture absorption soldering resistance,
26SOP was formed by transfer molding. 26S molded using the same epoxy resin composition for encapsulant
With respect to OPs, the ratio (percentage) of the number of defective packings such as voids and chips to the total number of OPs was defined as the molding defective rate.

The epoxy resin composition for a sealing material of each of Examples and Comparative Examples obtained in the amounts shown in Tables 3, 4 and 5 above, and the curing obtained using this epoxy resin composition Various properties of the product and the semiconductor device were evaluated by the above-described method. The obtained results are shown in Tables 6, 7, and 8.

[0038]

[Table 6]

[0039]

[Table 7]

[0040]

[Table 8]

From the results of Tables 6, 7 and 8, the following points were confirmed. In Comparative Example 1, since the ratio of the inorganic powder (B) having a larger linear expansion coefficient to the total filler than the amorphous silica was smaller, the linear expansion coefficient of the cured product of the epoxy resin composition was too small than that of the copper alloy, As a result, the heat shock resistance of the semiconductor device is poor.

In Comparative Example 2, since the ratio of the inorganic powder (B) having a larger linear expansion coefficient to the total filler than the amorphous silica was larger, the linear expansion coefficient of the cured product of the epoxy resin composition was too large. As a result, the heat shock resistance of the semiconductor device is poor.

In Comparative Examples 2 and 3, since the filler volume fraction (P) in the compression-molded compact of the used filler was smaller than 78%, the melt viscosity of the epoxy resin composition was increased. The fluidity is poor and molding failure occurs.

In Comparative Example 4, the proportion of the spherical amorphous silica powder having a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ² / g in all the fillers exceeded 20%. The melt viscosity of the product becomes high, resulting in poor fluidity and poor molding.

In Comparative Example 5, the ratio of the spherical amorphous silica powder having a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ² / g in all the fillers was less than 5%, so that the value of P was 78%. And the melt viscosity of the epoxy resin composition increases, resulting in poor fluidity and poor molding.

In Comparative Example 6, since the specific surface area of the spherical amorphous silica powder having a weight average particle diameter of less than 1 μm is more than 30 m ² / g, the melt viscosity of the epoxy resin composition is increased, so that the flowability is increased. And molding failure has occurred.

In Comparative Examples 2 to 6, in addition to the above, the semiconductor device slightly deteriorates in moisture absorption soldering resistance or heat shock resistance. This is because the melt viscosity is high and molding failure occurs. It is thought to be.

In Comparative Example 7, since the volume fraction of the filler in the epoxy resin composition is less than 70%, the moisture absorption of the cured product is large, and the moisture absorption solder resistance of the semiconductor device is extremely poor. The linear expansion coefficient (α ₁ ) of the cured product is large, and the heat shock resistance of the semiconductor device is also poor.

In Examples 1 to 8, within the scope of the present invention, the epoxy resin composition had a low melt viscosity and exhibited good moldability. A semiconductor device having good heat resistance and heat shock resistance is obtained. (Example 9) Granular epoxy resin YX400
0H 378 g, granular hardener OCN7000 27
9 g and 13.1 g of spherical amorphous silica SOC2 were mixed and pulverized to 200 mesh under with a Pulverizer AP-1SH type (manufactured by Hosokawa Micron Corporation) to obtain a mixed resin powder. Epoxy resin YX4 in Example 1
000H (37.8 g) and curing agent OCN7000 (2
7.9 g), and 67.0 g of the above-mentioned mixed resin powder of 200 mesh under is used instead of 65.7 g in total. Since 1.3 g of SOC2 is contained in this mixed resin powder, 426.2 g of the following filler F14 is blended in place of the filler F1 (427.5 g) in Example 1.

Filler F14: Each raw material filler was weighed at the weight shown in Table 9 and mixed with a rotary mixer.
It was produced by performing a dispersion treatment.

The total filler in Example 9 was the same as the mixed filler F14 and the SO added when the resin was pulverized.
C2, the volume fraction of the inorganic powder (B) having a larger linear expansion coefficient than the amorphous silica in the whole filler, the weight average particle diameter is less than 1 μm, and the specific surface area is 10 to 30 m ^2.
/ G of the spherical amorphous silica powder in the total filler,
Table 10 shows the true specific gravity of the entire filler and the filler volume fraction P in the compression-molded product.

As described above, the mixed resin powder was prepared and used in advance, and the filler F1 (42) in Example 1 was used.
7.5 g), and blended, mixed and kneaded in the same manner as in Example 1 except that 426.2 g of the filler of F14 was blended in place of 7.5 g) to obtain an epoxy resin composition and evaluate its performance. Table 11 shows the obtained results together with the results of Example 1.

[0053]

[Table 9]

[0054]

[Table 10]

[0055]

[Table 11]

As is clear from the results in Table 11, when the epoxy resin solid at room temperature was pulverized, the spherical amorphous silica powder having a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ² / g was used. The epoxy resin composition of Example 9 produced by adding and pulverizing to a resin and then mixing and kneading this mixed resin powder with other raw materials has a reduced melt viscosity,
Therefore, it was confirmed that the filler content could be further increased.

[0057]

According to the invention relating to the epoxy resin composition according to claims 1 to 5, the fluidity during molding is good and the semiconductor chip mounted on the copper alloy lead frame is sealed. An epoxy resin composition capable of improving the moisture absorption solder resistance and the heat shock resistance of a semiconductor device is obtained.

According to the sixth aspect of the present invention, it is possible to reduce the melt viscosity of the epoxy resin composition, and thus maintain good fluidity during molding. In addition, the filler content can be further increased.

According to the semiconductor device according to the seventh and eighth aspects of the present invention, it is possible to obtain a semiconductor device using a copper alloy lead frame which is excellent in both moisture absorption solder resistance and thermal stress resistance. it can.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H01L 23/31 (56) References JP-A-2-140226 (JP, A) JP-A 1-292029 (JP, A) JP-A-6 -5742 (JP, A) JP-A-5-9270 (JP, A) JP-A-4-345640 (JP, A) JP-A-6-177284 (JP, A) JP-A-4-253760 (JP, A) JP-A-3-26717 (JP, A) JP-A-5-205901 (JP, A) JP-A-5-230279 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08L 63/00-63/10 C08K 3/36 H01L 23/29

Claims (8)

(57) [Claims] 1. An epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a filler, as the filler, amorphous silica powder (A) and one kind having a larger linear expansion coefficient than the amorphous silica. It is a filler which is a mixed powder of the above inorganic powder (B), wherein the proportion of the inorganic powder (B) in the total filler is 20 to 60% by volume in terms of true specific gravity, and the weight average particle diameter is Filler containing spherical amorphous silica powder having a specific surface area of less than 1 μm and a specific surface area of 10 to 30 m ² / g in a total specific gravity of 5 to 20% by volume, and a pressure at which the average particle size is maintained. An epoxy resin composition, characterized in that a filler having a volume fraction of 78% or more in a molded product obtained by compressing the filler by using the filler is 78% or more. 2. The epoxy resin composition according to claim 1, wherein the inorganic powder (B) is crystalline silica. 3. The inorganic powder (B) is a glass powder.
The epoxy resin composition according to the above. 4. The epoxy resin composition according to claim 1, wherein the inorganic powder (B) is a hollow glass powder. 5. The epoxy resin composition according to claim 1, wherein the proportion of the filler in the epoxy resin composition is 70% by volume or more in terms of true specific gravity. 6. The method for producing an epoxy resin composition according to claim 1, wherein the contained epoxy resin and / or curing agent is solid at room temperature.
An epoxy resin and / or a curing agent which is solid at room temperature is mixed with a weight average particle diameter of less than 1 μm and a specific surface area of 10 to 30 m ^2.
/ G of spherical amorphous silica powder, followed by pulverization, followed by mixing and kneading with other raw materials. 7. A semiconductor device in which a semiconductor element mounted on a copper alloy lead frame is sealed using the epoxy resin composition according to any one of claims 1 to 5. 8. The semiconductor device according to claim 7, wherein the cured product of the epoxy resin composition has a linear expansion coefficient of 12 to 17 ppm / ° C.