JPH05156126A - Epoxy resin composition and its cured article - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition which is excellent in flowability in molding and gives a cured article having low stress and excellent soldering characteristics, especially moisture resistance and crack resistance after moisture absorption. CONSTITUTION:The objective epoxy resin composition contains an epoxy resin, a curing agent and an inorganic filler, wherein a powder obtained by grinding massive quartz and fine spherical silica is used as the inorganic filler.

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 suitable for semiconductor encapsulation, which has excellent fluidity during molding and is excellent in solder heat resistance and crack resistance after moisture absorption, and a cured product thereof. ..

[0002]

2. Description of the Related Art Epoxy resins and epoxy resin compositions in which an inorganic filler is added to the epoxy resins generally have better moldability, adhesiveness, and electrical properties than other thermosetting resin compositions. Because of its excellent properties, mechanical properties, moisture resistance, etc., it has been widely used as various molding materials, electrical insulating materials, etc., and has recently attracted attention as a semiconductor sealing material.

Recently, silicone-based modifiers and polybutadiene-based modifiers have been added for the purpose of imparting low stress properties to this epoxy resin composition, and the amount of inorganic filler added has been reduced in order to lower the expansion coefficient. Is being considered.

However, in such a method, although the stress property of the composition is lowered, when the amount of the inorganic filler added is increased, the fluidity at the time of molding is deteriorated, which is important for the sealing material such as low stress and fluidity. There is a serious drawback in that it is difficult to achieve good performance at the same time.

Recently, the package has become smaller and smaller,
In addition to the reduction in thickness, the surface mounting method has become the mainstream method for mounting on a substrate, and conventional epoxy resin compositions cannot maintain sufficient reliability. For example, when soldering is performed in a state where the package absorbs moisture, there are problems that a crack is generated in the package and the moisture resistance is lowered even if the crack is not generated. The cause of these problems is that the packaging material absorbs moisture.
For this reason, studies have been conducted to find out epoxy resins, curing agents, etc. having low hygroscopicity, but practically none have been developed yet.

Therefore, it has been desired to develop an epoxy resin composition having a cured product with low stress, excellent soldering characteristics, particularly moisture resistance after moisture absorption and crack resistance, and good fluidity during molding. ..

The present invention has been made in view of the above circumstances, and an epoxy resin having a low stress in a cured product, excellent soldering properties, particularly moisture resistance after moisture absorption and crack resistance, and good fluidity during molding. An object is to provide a resin composition and a cured product thereof.

[0008]

Means and Actions for Solving the Problems In order to achieve the above object, the present inventors have made earnest studies on an inorganic filler of an epoxy resin composition suitable for semiconductor encapsulation. In an epoxy resin composition containing an inorganic filler, use a powder obtained by pulverizing by adding fine spherical silica when pulverizing agglomerated quartz as an inorganic filler, and preferably this By using spherical silica having an average particle diameter of 5 to 35 μm in combination, the obtained cured product has low stress, soldering characteristics, particularly moisture resistance after moisture absorption and crack resistance, and fluidity during molding. The present invention has been found to be good, and the present invention has been completed.

The present invention will be described in detail below. The epoxy resin used in the present invention is not particularly limited as long as it has two or more epoxy groups in one molecule. For example, orthocresol novolac type epoxy resin. , Phenol novolac type epoxy resin, alicyclic epoxy resin, bisphenol type epoxy resin, substituted or unsubstituted naphthalene type epoxy resin, substituted or unsubstituted biphenyl type epoxy resin, substituted or unsubstituted triphenolalkane type epoxy resin, Examples thereof include halides of the above epoxy resins, and one or more of these are appropriately selected and used.

As the curing agent, one corresponding to the epoxy resin is used. For example, an amine type curing agent, an acid anhydride type curing agent, a phenol type curing agent and the like can be used. Among them, a phenol type curing agent is used. More desirable in terms of moldability and moisture resistance of the product. Specific examples of the phenol-based curing agent include phenol novolac resin, cresol novolac resin, naphthalene type resin, and triphenol alkane type resin.

Although the amount of the curing agent is not particularly limited, when a phenol novolac type curing agent is used, the molar ratio of the epoxy group in the epoxy resin to the phenolic hydroxyl group in the curing agent is 0.5. It is suitable to be in the range of 1.5.

Further, it is preferable to add a curing accelerator to the composition of the present invention in order to accelerate the reaction between the epoxy resin and the curing agent. As the curing accelerator, one or more of imidazole compounds, cycloamidine derivatives such as 1,8-diazabicyclo (5.4.0) undecene (DBU), phosphine derivatives such as triphenylphosphine, and tertiary amines. Is used. The amount of the curing accelerator used is not particularly limited, but is usually 0.01 to 5 parts by weight, preferably 0.2 to 3 parts by weight, based on the total amount of the epoxy resin and the phenol resin.

In the epoxy resin composition of the present invention, in addition to the above components, a powder obtained by pulverizing massive quartz together with fine spherical silica is used as an inorganic filler.

Here, the average particle size of the lump quartz to be crushed is usually about 0.1 to 100 mm, preferably 1 to 50 mm, and the average particle size of fine spherical silica added thereto is 0. 0.1 to 4 μm, particularly 0.5 to 2 μm is preferable. The addition amount of this fine spherical silica is
1 to 50 parts by weight, especially 5 to 100 parts by weight of lumped quartz
40 parts by weight, and 2 to 2 with respect to 100 parts by weight of the total filler.
It is preferably 5 parts by weight, particularly 4 to 17 parts by weight from the viewpoint of improving fluidity.

The crushing of the mixture of the lump quartz and the fine spherical silica can be carried out usually by a ball mill for 30 minutes to 5 hours, and the powder after crushing has an average particle diameter of 5 to 35 μm.
m, particularly preferably 7 to 30 μm. here,
As described above, in the method of mixing the crushed silica obtained by crushing only the lumped quartz with the crushed silica obtained by crushing only the lumped quartz without crushing the mixture of the lumped quartz and the fine spherical silica, with a mixing device such as a Henschel mixer or a V-blender, There are drawbacks that the fine spherical silica is not sufficiently dispersed and secondary aggregates of the fine spherical silica are easily generated.

On the other hand, by pulverizing a mixture of agglomerated quartz and fine spherical silica, the fine spherical silica is sufficiently dispersed, there are no secondary aggregates, and the epoxy resin composition has excellent fluidity. become. If 0.05 to 2% by weight of water or a silane coupling agent is added at the time of pulverization, fine silica sticks to the surface of the crushed silica, and the dispersibility is further improved.

In the present invention, it is preferable to use spherical silica having an average particle diameter of 5 to 35 μm in combination with the above powder, which further improves the fluidity.

Here, the powder and the average particle diameter are 5 to 35.
The compounding amount of the spherical silica of μm is 250 to 80 with respect to 100 parts by weight of the total amount of the epoxy resin and the curing agent.
0 parts by weight, especially 300 to 700 parts by weight, spherical silica 0 to 600 parts by weight, especially 50 to 150 parts by weight, and the total amount of both is 250 to 850 parts by weight, especially 3 parts by weight.
It is preferably from 0.00 to 650 parts by weight. Compounding amount is 2
If it is less than 50 parts by weight, the internal stress cannot be sufficiently reduced, and if it is more than 850 parts by weight, the fluidity of the resin is remarkably reduced, and molding may be difficult.

When the filler is used, it is preferable that the surface of the filler is previously treated with a surface treating agent such as an organic silicon compound, a titanate or an organic aluminum. Among these, what is called a silane coupling agent is particularly desirable.

In addition to the above-mentioned inorganic fillers, other fillers may be added to the composition of the present invention. Typical examples of these fillers are crystalline silica, alumina, talc, kaolin, silicon nitride, aluminum nitride, boron nitride, glass fiber and the like.

Further, in the present invention, it is preferable to add a silicone polymer or a thermoplastic polymer to the epoxy resin composition for the purpose of reducing stress, and the addition of these polymers causes the generation of package cracks in a thermal shock test. It can be significantly reduced.

Examples of the silicone polymer include silicone oil, silicone resin or silicone rubber having an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a hydrosilyl group, a vinyl group, etc., and further, these silicone polymers and phenol novolac resins, epoxidized. A copolymer with an organic polymer such as phenol novolac resin can be used. Further, fine powder of silicone rubber or gel can also be used.

MBS resin, butyral resin, aromatic polyester resin and the like are typical examples of the thermoplastic resin.

The blending amount of these resins is preferably 1 to 50 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.

Further, a coupling agent, a coloring agent, a releasing agent, a halogen trapping agent and the like may be appropriately added to the composition of the present invention.

The composition of the present invention can be obtained by kneading the above-mentioned components, and as a kneading method, a kneader, a roll mill or a continuous kneader may be usually used.

The epoxy resin composition of the present invention is
It is preferably used for sealing semiconductor devices such as SI and transistors. Here, when the semiconductor device is sealed, conventionally used molding methods such as a transfer molding method, an injection molding method, and a casting method are used. In this case, the molding temperature is preferably 150 to 180 ° C.

[0028]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Examples 1 to 4 and Comparative Example 1 58 parts of epoxidized cresol novolac resin having an epoxy equivalent of 200 and a softening point of 65 ° C., 6 parts of brominated epoxidized phenol novolac resin having an epoxy equivalent of 280, and 11 equivalents of phenol.
0, 36 parts of phenol novolac resin with a softening point of 80 ° C,
0.7 parts of triphenylphosphine, 1 part of antimony trioxide
0 parts, carnauba wax 1.5 parts, γ-glycidoxypropyltrimethoxysilane 1.6 parts, and carbon black 1 part were used as a base, and a predetermined amount of silica was blended into this base, which was then mixed with a mixing roll at 80 ° C. After melt-mixing for 5 minutes, it was taken out into a sheet form, cooled and pulverized to prepare an epoxy resin composition.

The following tests were conducted on the obtained composition. The results are shown in Table 1. (1) Spiral flow 175 ° C, 70k using a mold conforming to EMMI standard
It was measured under the condition of g / cm ² . (2) After molding with a coefficient of expansion, a glass transition temperature of 175 ° C., 70 kg / cm ² and a molding time of 2 minutes,
Created under the conditions of 180 ° C / 4Hr post cure 5
It measured using the Agne (Vacuum Riko Co., Ltd.) using the test piece of x5x15mm. (3) Bending strength (3-1) Room temperature measurement According to JIS-K6911, 175 ° C, 70 kg / cm
² 、 Create a test piece under the condition of molding time 2 minutes, 180 ℃ /
It measured about what was post-cured for 4 hours. (3-2) After Moisture Absorption Treatment The test piece prepared and post-cured in 3-1 was left standing in a PCT (pressure cooker) for 100 hours and then measured. (4) Solder crack after moisture absorption QFP having a thickness of 2.7 mm was molded under the conditions of 175 ° C., 70 kg / cm ² , and molding time of 2 minutes, and post-cured at 180 ° C./4Hr. This package is 35 ℃ / 85% RH
After being left in the atmosphere for 24 hours for a moisture absorption treatment, it was immersed in a solder bath at 260 ° C. for 10 seconds. The crack generation defect rate of the package generated at this time was examined.

[0031]

[Table 1]

Silica No. 1: Aggregate quartz (particle size of about 20 ~
30 g) and 200 g of fine spherical silica having an average particle size of 1 μm were charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 12 μm, and the secondary aggregate remaining on the 200-mesh sieve was 0.1% or less. 300 parts by weight of this powder and 200 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials) having an average particle size of 30 μm were mixed.

Silica No. 2: Lumped quartz (particle size of about 20 ~
30 g) and 200 g of fine spherical silica having an average particle size of 1 μm were charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 12 μm, and the secondary aggregate remaining on the 200-mesh sieve was 0.1% or less. 300 parts by weight of this powder and 200 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials) having an average particle diameter of 30 μm were surface-treated with 3 parts by weight of a coupling agent (KBM403 manufactured by Shin-Etsu Chemical) and blended.

Silica No. 3: Agglomerated quartz (particle size of about 20 ~
(30 mm) 1000 g, 400 g of fine spherical silica having an average particle size of 1 μm was charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 10 μm, and the amount of secondary aggregates remaining on the 200-mesh sieve was 0.1% or less. 150 parts by weight of this powder and 350 parts by weight of spherical silica (BF015, manufactured by Mitsubishi Materials) having an average particle size of 15 μm were surface-treated with 3 parts by weight of a coupling agent (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.).

Silica No. 4: Agglomerated quartz (particle size of about 20 ~
(30 mm) 1000 g, 400 g of fine spherical silica having an average particle size of 1 μm was charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 10 μm, and the amount of secondary aggregates remaining on the 200-mesh sieve was 0.1% or less. 200 parts by weight of this powder and 400 parts by weight of spherical silica (BF015, manufactured by Mitsubishi Materials) having an average particle size of 15 μm were surface-treated with 3 parts by weight of a coupling agent (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.).

Silica No. 5: 1000 g of crushed silica having an average particle size of 15 μm, fine spherical silica 2 having an average particle size of 1 μm 2
00 g was placed in a Henschel mixer and mixed for 10 minutes. 2 secondary agglomerates remaining on the 200 mesh screen
%Met. 300 parts by weight of this powder and an average particle size of 30 μm
200 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials).

[Examples 5 to 7] Epoxidized cresol novolac resin 58 having an epoxy equivalent of 200 and a softening point of 70 ° C.
Parts, epoxy equivalent 280, brominated epoxidized phenol novolac resin 6 parts, phenol equivalent 110, softening point 8
Based on 36 parts of phenol novolac resin at 0 ° C, 0.7 parts of triphenylphosphine, 10 parts of antimony trioxide, 1.5 parts of carnauba wax, 1.6 parts of γ-glycidoxypropyltrimethoxysilane and 1 part of carbon black. As a base material, add a certain amount of silica to this base,
After melt-mixing with a mixing roll at 0 ° C. for 5 minutes, it was taken out in a sheet form, cooled and pulverized to prepare an epoxy resin composition.

Regarding the obtained composition, the above (1) to
In addition to (4), the following tests (5) were conducted. The results are shown in Table 2. (5) Burr characteristics Molding was performed using a burr die under the conditions of 180 ° C / 70 kg / cm ² , and the length of the burr that appeared in the slit having a thickness of 30 µm was measured.

[0039]

[Table 2]

Silica No. 6: Agglomerated quartz (particle size of about 20 ~
(30 mm) and 300 g of fine spherical silica having an average particle size of 0.5 μm were charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 12 μm,
Secondary aggregates remaining on the 0 mesh sieve were 0.1% or less. 250 parts by weight of this powder and an average particle size of 30 μm
250 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials).

Silica No. 7: Aggregate quartz (particle size about 20-
(30 mm) 1000 g, 300 g of fine spherical silica having an average particle size of 1 μm was charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 12 μm, and the secondary aggregate remaining on the 200-mesh sieve was 0.1% or less. 250 parts by weight of this powder and 250 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials) having an average particle size of 30 μm were mixed.

Silica No. 8: Aggregate quartz (particle size of about 20 ~
30 mm) and 300 g of fine spherical silica having an average particle size of 3 μm were charged in a ball mill and pulverized for 60 minutes. The average particle size of the obtained silica was 13 μm, and the amount of secondary aggregates remaining on the 200-mesh sieve was 0.1% or less. 250 parts by weight of this powder and 250 parts by weight of spherical silica (BF100 manufactured by Mitsubishi Materials) having an average particle size of 30 μm were mixed.

[0043]

EFFECT OF THE INVENTION The epoxy resin composition of the present invention provides a cured product having excellent fluidity after molding, low stress, and excellent solder characteristics, particularly moisture resistance after moisture absorption and crack resistance.

Front page continuation (72) Inventor Hatsuji Shiraishi 1 Hitomi, Katsura, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory

Claims (2)

[Claims] 1. An epoxy resin composition containing an epoxy resin, a curing agent, and an inorganic filler, wherein a powder obtained by pulverizing lump quartz with fine spherical silica is used as the inorganic filler. A characteristic epoxy resin composition. 2. A cured product of the composition according to claim 1.