JPH07206983A - Epoxy resin composition, its production and semiconductor apparatus obtained by using the composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition capable of improving moisture-soldering resistance (resistance to the separation at the soldered position caused by the moisture absorbed) and heat shock resistance of a semiconductor apparatus in which a semiconductor chip loaded on a lead frame made of copper alloy is sealed with a resin and to provide the production method for the epoxy resin composition and a semiconductor apparatus sealed by the epoxy resin composition. CONSTITUTION:The filler of this epoxy resin composition has the following features. It is a mixture of amorphous silica powder A with >=1 kind of inorganic powder B having a larger coefficient of linear expansion than the amorphous silica powder. The content ratio of the inorganic powder B in the total filler material is 20-60vol.% in terms of true specific gravity of the components. Spherical amorphous silica powder having a weight average particle diameter of <1mum and specific gravities of 10-30m<2>/g is contained in an amount of 5-20vol.% based on the total filler material in terms of true specific gravity of the components. Further, when the molded article is produced by the compression under a pressure at which the average particle diameter of the filler is maintained, the fraction of the volume of the filler in the molded article is >=78%.

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 encapsulating material for protecting semiconductors, a method for producing the same, and an encapsulation type semiconductor device using the epoxy resin composition for encapsulating material.

[0002]

2. Description of the Related Art With the progress of the advanced information society and the progress of semiconductors, the functions given to integrated circuits are increasing, and the degree of integration and the operating 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 a high thermal conductivity is often used as a lead frame. Since the linear expansion coefficient of copper alloy is different from that of 42 alloy, the conventional 42 is used as an encapsulating material for encapsulating an integrated circuit of a large chip mounted on a copper alloy lead frame.
A performance different from that of the encapsulant for the integrated circuit mounted on the alloy lead frame is required. Linear expansion coefficient of each material (α
[ppm / ° C.]), copper alloy is 16-18, 42 alloy is 5-7, and silicon chip is 3-
It is 4. In the case of the 42 alloy lead frame, since both the chip and the lead frame have small α, the target α of the cured product of the sealing material is about 10 ppm / ° C or less.
Studies on making the volumetric content of amorphous silica in the encapsulant 70% or more have been continued. On the other hand, in the case of a copper alloy lead frame, when α of the cured product of the encapsulant is reduced to about 42 alloy, the difference in thermal expansion between the cured product of the encapsulant and the lead frame becomes large, and a heat shock test or a heat cycle test is performed. Since a defect occurs in a test such as a test for checking a defect due to thermal stress, it is unavoidable that α of the cured product of the sealing material is slightly large. For this reason, the content of the amorphous silica, which is the filler in the encapsulant, is generally about 70% by volume or less.

On the other hand, in order to increase the packaging density, surface-mounting type thin semiconductor devices have become mainstream. In this surface-mounting type semiconductor device, it is considered that the moisture absorption of the cured material of the sealing material is the cause. After the soldering process, the cured product of the encapsulating material and the chip, or the cured product of the encapsulating material and the lead frame on the back of the die pad are apt to peel off (bad moisture absorption soldering resistance). In order to solve this, it is most effective to use a sealing material having a high filler content to reduce the moisture absorption of the cured product of the sealing material, and it is desired to realize this method.

[0004]

Since the volume fraction of the filler in the copper alloy lead frame encapsulant is low, it means that the resin component is large, and the moisture absorption of the cured product of the encapsulant obtained is high. Semiconductor device (package)
However, there is a problem that the moisture absorption solder resistance cannot be improved. This is an issue that needs to be solved urgently as the mounting form of semiconductors is shifting to the surface mounting type in recent years. Further, in the surface-mounting type semiconductor device, since the thickness of the portion where the sealing material is used is thin, defective filling and voids are likely to occur during molding, and the fluidity of the sealing material is maintained well. As it is, it is necessary to improve various characteristics such as moisture absorption solder resistance and heat shock resistance.

The present invention has been made in view of the above situation, and an object of the present invention is to prevent moisture absorption and solder resistance of a semiconductor device in which a semiconductor chip mounted on a copper alloy lead frame is sealed. An epoxy resin composition having improved heat shock resistance and a method for producing the same are provided, and a sealed semiconductor device excellent in moisture absorption solder resistance and heat shock resistance using the epoxy resin composition is provided. It is to be.

[0006]

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

The invention relating to the method for producing an epoxy resin composition comprises an epoxy resin and / or a curing agent which are solid at room temperature, have a weight average particle diameter of less than 1 μm and a specific surface area of 10 μm.
It is characterized in that it is pulverized in the state of adding spherical amorphous silica powder of ˜30 m ² / g, and then mixed and kneaded with other raw materials.

The invention relating to a semiconductor device is defined in claim 1.
The semiconductor element mounted on a copper alloy lead frame is sealed with the epoxy resin composition according to any one of claims 1 to 5.

The present invention will be described in detail below. Among the fillers used in the epoxy resin composition for encapsulant, amorphous silica has a linear expansion coefficient of 0.5 to 0.7 ppm / ° C., and since the particle shape can be made spherical, the filler is encapsulant. It is widely used for the purpose of lowering moisture absorption and lowering the coefficient of linear expansion of the cured product of the encapsulating material because it can be easily filled with a high content. However, the higher the filling amount of amorphous silica, the lower the linear expansion coefficient of the cured product of the encapsulant, and generally the α of the cured product of the encapsulant containing 70% by volume or more is less than 12 ppm / ° C., The difference with the copper alloy lead frame will widen. Therefore, in the present invention, the amorphous silica powder (A) and one or more kinds of inorganic powder (B) having a linear expansion coefficient larger than that of the amorphous silica are used, and the volume mixing ratio focusing on the true volume of each powder. 80/20 to 4
By using 0/60 mixed powder as a filler, even if the filler content is increased, the linear expansion coefficient of the cured product of the encapsulant is maintained in a preferable range for a copper alloy lead frame. If the volume fraction of the inorganic powder (B) in terms of true specific gravity in all the fillers is less than 20%, the linear expansion coefficient of the cured product becomes low, and if it exceeds 60%, the linear expansion coefficient of the cured product becomes large. Not preferable.

Further, in order to lower the moisture absorption rate of the cured product of the sealing material and improve the moisture absorption solder resistance, it is necessary to highly fill the sealing material with the filler. As the highly packable filler, it is necessary to minimize the free volume between particles, which has a weight average particle diameter of less than 1 μm and
Spherical amorphous silica having a specific surface area of 10 to 30 m ² / g,
Of the filler in the molded product obtained by compounding so as to occupy 5 to 20% by volume in terms of true specific gravity with respect to all the filler, and compressing the filler at a pressure at which the average particle size is maintained. This can be achieved by using a filler having a volume fraction of 78% or more.

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

D = Σwi / Σ (wi / di) ────────────────────────────────────────── (C) Then, when the volume fraction of the filler in the compact obtained by compression is P, P is W grams. From the apparent volume V cubic centimeter of the molded body obtained by compressing a certain inorganic filler, it is calculated by the following formula (D).

P = 100 (W / d) / V ──────── (D) And, in the present invention, the molding pressure of the compression molding of the inorganic filler for measuring the volume fraction P is before compression molding. It is important that the average particle size of is the pressure that is maintained even after compression molding. If this molding pressure is too high, the particles of the inorganic filler are destroyed, the average particle size after compression molding becomes different from the average particle size before compression molding, and the measured volume fraction P is the epoxy resin composition. The disadvantage occurs that the properties of the inorganic filler therein are not exhibited. This is because, with any inorganic filler, if the molding pressure during compression molding is made extremely high, the particles will be destroyed and the resulting molded body will approach a state in which voids are not included, and the measured volume fraction P Is 100
This is because it becomes asymptotic to%. Therefore, in the present invention, the inorganic filler in the molded body obtained by compression molding,
As it exists in the same state as the inorganic filler to be contained in the epoxy resin composition, the molding pressure during compression molding is such that the average particle size of the inorganic filler before compression molding is carried out at a pressure that is retained even after compression molding. Limited.

The volume fraction P of the inorganic filler before compression molding obtained by the molded body molded at the maximum pressure (hereinafter abbreviated as Fmax) within the range of pressure retained after compression molding is , Fmax, which is always larger than the volume fraction P obtained by the molded body. That is, when the volume fraction P of the inorganic filler in 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 volume fraction (abbreviated as Vs) in terms of true specific gravity with respect to all fillers of 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 is 5% by volume or less. In addition, it is difficult to set P to 78% or more, and burrs are increased when molding the epoxy resin composition, which is not preferable. Further, when Vs exceeds 20% by volume, the P can be 78% or more, but the number of particles in the total filler becomes too large, so that the composition becomes a molten state when molding the epoxy resin composition. It is not preferable because molding defects are likely to occur, which is considered to be due to the non-Newtonian property or thixotropic property of the product becoming too large.

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

When the final epoxy resin composition is applied to the sealing of the memory element, the above-mentioned filler is used for the purpose of avoiding a soft error of the memory element due to α rays, such as uranium or thorium. It is preferable to use a so-called α-ray-free filler having a content of a radioisotope serving as an α-ray source of at least 1 ppb or less.

By containing the above-mentioned filler in the epoxy resin composition in an amount of 70 vol% 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 enhance the moisture absorption solder resistance of the semiconductor device using the copper alloy lead frame, and the linear expansion rate of the cured product between 50 and 100 ° C. By setting 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 improved.
The linear expansion coefficient at 50 to 100 ° C. is
It also changes depending on the structure and the compounding ratio of the curing agent and the organic material 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 linear expansion coefficient (α ₂ ) after Tg of the resin comes in between 50 and 100 ° C. Compared to the case of a resin having a Tg of a hundred and several tens of degrees C.
The coefficient of linear expansion between 100 ° C increases. However, regardless of the characteristics of the resin, the linear expansion coefficient between 50 and 100 ° C. of the cured product of the epoxy resin composition is 12 to 17 ppm.
If it is / ° C, heat shock resistance can be improved.

The above-mentioned filler is preferably surface-treated with a coupling agent in order to strengthen the chemical bond with the resin. This method may be carried out by treating the powder particle surface with a coupling agent in advance and then kneading with the resin, or by kneading the resin component with the coupling agent and then kneading with the filler, which is a so-called integral blending method. Anything is fine.

Further, 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 novolac type epoxy resin,
Cresol novolac type epoxy resin, bisphenol A type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene-phenol copolymer type epoxy resin, epoxy resin in which at least two epoxy groups are bonded to one benzene ring And so on. Further, as the curing agent, there are a phenol type curing agent, an amine type compound and the like, but it is preferable to use a phenol type curing agent which is effective in reducing the moisture absorption rate of the cured product. The phenolic curing agent is a compound having two or more phenolic hydroxyl groups in one molecule, and examples thereof include phenol novolac resin and its derivative, cresol novolac resin and its derivative, mono- or dihydroxynaphthalene and its derivative, dicyclo Examples thereof include copolymers of pentadiene and phenol, hydroxystyrene and derivatives thereof. It is desirable to use these epoxy resins and curing agents having a low melt viscosity in order to increase the filler content to reduce moisture absorption and to maintain good fluidity during molding.

Examples of the curing accelerator used in the present invention include triphenylphosphine and its derivatives, diazabicycloundecene and its salts, and 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 they do not interfere with the object of the present invention. For example, waxes for imparting a releasing effect, pigments and dyes as colorants, ion trap agents for capturing impure ions to improve moisture resistance reliability, various flame retardants for imparting flame retarding effect. It is a low stress imparting component typified by a flame retardant and an elastomer for reducing the elastic modulus or linear expansion coefficient.

Further, it was 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, of the epoxy resin and / or the curing agent that are solid at room temperature,
In the method for finally producing an epoxy resin composition, the epoxy resin composition is pulverized in whole or in part to be a resin powder, and then mixed with other raw materials, and finally kneaded to produce an epoxy resin composition. When crushing the resin and / or the curing agent, the weight average particle diameter is less than 1 μm and the specific surface area is 10
The method is characterized in that ˜30 m ² / g of spherical amorphous silica powder is added to the resin. In the production of an epoxy resin composition, it is common to make necessary resin components into fine powder and then mix and knead them, but the resin fine powder has a strong tendency to agglomerate or cake, and it may be used as a filler other than the resin fine powder. By the time they are mixed, most of them have become large particles. Therefore, when the resin component is melted during kneading, it takes in an agglomerate composed of fine filler particles in the vicinity to form an agglomerate by strong liquid crosslinking such as so-called "damage", and this agglomerate is also kneaded. It is believed that it will not completely disappear. According to the production method of the present invention, a layer of silica particles having a weight average particle size of less than 1 μm is formed on the surface of the fine powder of the resin component, whereby the fine resin powder is prevented from aggregating or caking, and other than the resin component. When mixed with the components, the blended components are extremely finely and uniformly dispersed, and the residual amount of filler aggregates after kneading is reduced, whereby the fluidity of the epoxy resin composition is improved. It should be noted that when the spherical amorphous silica powder is added to the epoxy resin and / or the curing agent which are solid at room temperature and the mixture is pulverized, another resin component 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 [Yukaka Shell Epoxy Co., Ltd., product number YX-4000.
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 group equivalent 140,
Melting temperature 120 ° C.] is used, and triphenylphosphine [manufactured by Kitako Chemical Industry Co., Ltd., hereinafter T
PP) is used, the wax is natural carnauba wax, and the coupling agent is an epoxysilane coupling agent [manufactured by Nippon Unicar Co., Ltd., product number A-187].
Was used, and the pigment used was carbon black.

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

Further, the following two kinds of fillers were used as the amorphous silica powder (A). Spherical amorphous silica manufactured by Tatsumori, product number SOC2, average particle size 0.5 μm, specific surface area 12 m ² / g, true specific gravity 2.
2 ──── Hereinafter referred to as SOC2. Spherical amorphous silica manufactured by Denki Kagaku Co., Ltd., product number FB
No. 01, average particle diameter 0.1 μm, specific surface area 35 m ² / g, true specific gravity 2.2 ───hereinafter referred to as FB01.

The following three types of inorganic powder (B) having a linear expansion coefficient larger than that of amorphous silica were used. Tatsumori Co., Ltd. crystalline silica, product number 3K, average particle size 27
μm, specific surface area 2 m ² / g, true specific gravity 2.6 ─── and 3K thereafter. Spherical E glass powder (glass beads) manufactured by Toshiba Ballotini Co., Ltd., product number GB731, average particle size 30 μm, true specific gravity 2.6 ── henceforth GB731. Hollow glass powder (borosilicate glass balloon) manufactured by Toshiba Ballotini Co., Ltd., product number HSC110, average particle diameter 10 μm, true specific gravity 1.1 ──hereinafter referred to as HSC110.

Next, the mixed filler used in each example and each comparative example will be described. Raw material fillers were sampled in 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 molded body 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 molded body obtained by compressing the mixed filler was determined as follows. The mixed filler having a weight of W grams was 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 The mixed filler volume fraction P in the molded body was calculated from the weight W of the above and the true specific gravity d of the entire filler by the above-mentioned formula (D). Then, the average particle size of the mixed filler after compression molding by crushing the obtained molded body is measured, and compared with the average particle size of the mixed filler before molding, which is used for molding, and the obtained molded body is also averaged. It was investigated whether the particle size was maintained. As a result, with the mixed filler used in each of the examples and comparative examples, the average particle size was maintained even in the obtained molded bodies, and it was found that the particles were not broken by compression molding at a compression pressure of 300 kg / cm ^2. confirmed.

[0030]

[Table 1]

[0031]

[Table 2]

(Examples 1 to 8 and Comparative Examples 1 to 7) The mixed fillers (F1 to F13) shown in Tables 1 and 2 were used to seal Examples 1 to 8 and Comparative Examples 1 to 7. An epoxy resin composition for wood was prepared. The mixing ratio of the epoxy resin composition is as shown in Tables 3, 4 and 5, and the coupling agent is sprayed with a required amount on the mixed fillers (F1 to F13) and dispersed and mixed in advance with a mixer, and then other components. Mixed with the ingredients. Moreover, the kneading of the blend of each raw material was performed for 6 minutes with 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 performances of the obtained epoxy resin composition for encapsulant, cured products obtained by using the epoxy resin composition and semiconductor devices were evaluated as follows. (1) Gel time: The gel time of each epoxy resin composition at 175 ° C. was measured using a curast meter V type manufactured by Orientec Co., Ltd. (2) Linear expansion coefficient of the cured product: Using a dedicated mold, transfer molding at 175 ° C. to obtain a cylindrical molded product of 5 mmφ × 20 mm, followed by after-curing at 175 ° C. for 6 hours, and then polishing. The bottom surface and the top surface were parallelized to prepare a test piece for measuring linear expansion coefficient. About this test piece, TAS20 manufactured by Rigaku Denki Co., Ltd.
The linear expansion coefficient (α ₁ ) between 50 ° C. and 100 ° C. was measured by a 0 type TMA device. (3) Moisture absorption soldering resistance: CMOS of 4 × 12 × 0.4 mm
The element is mounted on a lead frame made of a copper alloy [Mitsubishi Electric Corp., product number MF202] with silver paste and bonded with a gold wire, and then an epoxy resin composition for encapsulant is used. 17.4 x 2.7 mm 26SO
Transfer molding was performed with a die for P package. The molding conditions are a temperature of 175 ° C., an injection time of 12 seconds, and a pressurization time of 90.
Second, the injection pressure was 70 kg / cm ² . The obtained molded product was subjected to after-curing at 175 ° C. for 6 hours to obtain 26SOP (semiconductor device) for performance evaluation. The obtained semiconductor device is left in an atmosphere having a temperature of 85 ° C. and a relative humidity of 85% for 72 hours, and then immersed in a solder bath at 260 ° C. for 10 seconds to seal the back surface of the die pad of the copper alloy lead frame inside the semiconductor device. Ultrasonic probe for the interface between the hardened material and the hardened material [Canon Co., Ltd., product number M-700II]
Observation was made, and the case where the peeling mode portion was generated was determined to be defective. In addition, the outside of the semiconductor device was observed with a stereoscopic microscope, and those having cracks were determined to be defective. (4) Heat shock resistance: 26SOP (semiconductor device) for performance evaluation was obtained in the same manner as in the case of moisture absorption solder resistance.
This semiconductor device is in a liquid phase at −65 ° C. for 5 minutes to + 150 ° C. 5
The heat shock test with 1 minute as a cycle is repeated, and after the test of the number of cycles shown in Table 6, Table 7 and Table 8 is completed, in the same manner as in the case of the moisture absorption solder resistance, the copper alloy lead frame in the semiconductor device is The adhesion state at the interface between the back surface of the die pad 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 and solder resistance,
26SOP was molded by transfer molding. 26S molded using the same epoxy resin composition for encapsulant
Regarding OP, the ratio (percentage) of the number of defective filling such as voids and chips to the total number of OP was defined as the defective molding rate.

Epoxy resin compositions for encapsulants of Examples and Comparative Examples obtained in the compounding amounts shown in Tables 3, 4 and 5 and curing obtained by using the epoxy resin compositions. Various properties of the product and the semiconductor device were evaluated by the above-mentioned methods. The obtained results are shown in Tables 6, 7, and 8.

[0038]

[Table 6]

[0039]

[Table 7]

[0040]

[Table 8]

From the results shown in 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 than that of the amorphous silica to the total filler is small, the linear expansion coefficient of the cured product of the epoxy resin composition becomes too smaller 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 than that of the amorphous silica to the total filler is large, the cured product of the epoxy resin composition has a too large linear expansion coefficient. 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 molded body of the mixed filler used was smaller than 78%, the melt viscosity of the epoxy resin composition was increased. In addition, the fluidity is poor and molding failure occurs.

In Comparative Example 4, since the ratio of the spherical amorphous silica powder having a weight average particle size of less than 1 μm and a specific surface area of 10 to 30 m ² / g to the total filler exceeds 20%, an epoxy resin composition is obtained. The melt viscosity of the product is increased, resulting in poor fluidity and defective molding.

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

In Comparative Example 6, since the specific surface area of the spherical amorphous silica powder having a weight average particle size of less than 1 μm exceeds 30 m ² / g, the melt viscosity of the epoxy resin composition is increased and the fluidity is increased. Is bad and molding failure has occurred.

In Comparative Examples 2 to 6, the moisture absorption solder resistance or the heat shock resistance of the semiconductor device was slightly deteriorated, in addition to the above, because the melt viscosity was high and defective molding occurred. It is supposed to do.

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

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

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

All the fillers in Example 9 were the same as the mixed filler F14 and the SO added when the resin was crushed.
C2, the volume fraction of the inorganic powder (B) having a larger linear expansion coefficient than the amorphous silica in all the fillers, the weight average particle diameter is less than 1 μm, and the specific surface area is 10 to 30 m ^2.
% Of spherical amorphous silica powder in all fillers,
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 in advance and used, and the filler F1 (42) in Example 1 was used.
The composition was mixed, mixed and kneaded in the same manner as in Example 1 except that 426.2 g of F14 filler was mixed instead of 7.5 g) to obtain an epoxy resin composition, and the performance was evaluated. The results obtained are shown in Table 11 together with the results of Example 1.

[0053]

[Table 9]

[0054]

[Table 10]

[0055]

[Table 11]

As is clear from the results shown in Table 11, when the solid epoxy resin is crushed at room temperature, spherical amorphous silica powder having a weight average particle size of less than 1 μm and a specific surface area of 10 to 30 m ² / g is obtained. The epoxy resin composition of Example 9 produced by adding to a resin and pulverizing, and then mixing and kneading the 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 of claims 1 to 5, the fluidity at the time of molding is good, and the semiconductor chip mounted on the copper alloy lead frame is sealed. An epoxy resin composition that can improve moisture absorption solder resistance and heat shock resistance of a semiconductor device can be obtained.

According to the invention of the method for producing an epoxy resin composition of claim 6, the melt viscosity of the epoxy resin composition can be lowered, and therefore, the fluidity during molding can be kept good. Further, it becomes possible to further increase the filler content.

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

Claims (8)

[Claims] 1. An epoxy resin composition containing an epoxy resin, a curing agent, a curing accelerator, and a filler, and as the filler, one kind having a larger linear expansion coefficient than the amorphous silica powder (A) and the amorphous silica. The filler is a mixed powder of the above inorganic powder (B), and 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 A 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 an amount of 5 to 20% by volume in terms of true specific gravity in all fillers, and further, a pressure at which the average particle diameter is maintained. An epoxy resin composition, characterized in that a filler having a volume fraction of 78% or more in the molded body obtained by compressing the filler is used. 2. The epoxy resin composition according to claim 1, wherein the inorganic powder (B) is crystalline silica. 3. The inorganic powder (B) is glass powder.
The epoxy resin composition described. 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 any one of claims 1 to 5, wherein the contained epoxy resin and / or curing agent is solid at room temperature.
Epoxy resin and / or curing agent that are solid at room temperature have a weight average particle size of less than 1 μm and a specific surface area of 10 to 30 m ^2.
/ G of spherical amorphous silica powder is added thereto, and the mixture is pulverized, and then mixed and kneaded with other raw materials, which is a method for producing an epoxy resin composition. 7. A semiconductor device obtained by encapsulating a semiconductor element mounted on a copper alloy lead frame using the epoxy resin composition according to any one of claims 1 to 5. 8. The semiconductor device according to claim 7, wherein a cured product of the epoxy resin composition has a coefficient of linear expansion of 12 to 17 ppm / ° C.