JP2001139725A - Inorganic powder and resin composition filled therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which has high heat conductivity.high flowabiliy.low mold wearability and is useful for sealing materials and so on, and to provide inorganic powder suitable for producing the resin composition. SOLUTION: This inorganic powder characterized by comprising spherical silica powder having an average particle diameter of <=1.0 μm and an average spherical degree of >=0. 90 and spherical alumina powder having an average spherical degree of >=0. 85 and consisting mainly of particles having particle diameters in the range of 1 to 96 μm, wherein the content of the spherical silica powder is 3 to 30%. And the resin composition characterized by containing the inorganic powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic powder and a resin composition filled with the inorganic powder,
It is suitable for the production of insulating sealing materials for electric equipment and various substrates.

[0002]

2. Description of the Related Art In recent years, the amount of heat generated by ICs has been increasing with the advancement of higher functions and higher speeds. In response to this, there has been an increasing demand for high heat dissipation properties for sealing materials, and studies are being made on both sides of the epoxy resin and filler that constitute the sealing materials. Conventionally, aluminum nitride, silicon nitride and aluminum oxide (alumina) have been mainly used as high thermal conductive fillers, but these have advantages and disadvantages.

[0003] Aluminum nitride and silicon nitride have high thermal conductivity of 100 W / m · K or more, so that the thermal conductivity of the sealing material can be increased, but they are non-spherical and non-oxide. From the point of view of problems such as reduced fluidity of the sealing material, severe mold abrasion during molding, and the generation of ammonia by reacting with moisture in the air, etc. Has not been reached.

On the other hand, since alumina does not react with moisture, there is no concern about generation of ammonia. However, fluidity and mold abrasion are at the same level as the above-mentioned nitride, and there is still room for improvement. Therefore, Japanese Patent Application Laid-Open No. Hei 5-29461
No. 3, JP-A-11-147711,
Proposals have been made to use alumina particles in a spheroidized form, but this is not yet sufficient, and development of a sealing material having high thermal conductivity, high fluidity and low mold wear has been awaited.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a resin composition such as a sealing material having high thermal conductivity, high fluidity, and low mold wear. And to provide an inorganic powder used for the same.

[0006]

That is, according to the present invention, an average particle size is 1.0 μm or less and the average sphericity is 0.90.
The above-mentioned spherical silica powder and a particle diameter range of 1 to 96 μm
And a spherical alumina powder having an average sphericity of 0.85 or more and a spherical silica powder content of 3 to 30%. Further, the present invention is a resin composition comprising the inorganic powder.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The inorganic powder of the present invention comprises a spherical alumina powder and a spherical silica powder having finer particles and a larger average sphericity than the spherical alumina powder. The reason for this is that the thermal conductivity of alumina itself is 30 W / m
-Although it is smaller than K and is smaller than that of the nitride, the filling amount is high in the resin composition (hereinafter, also referred to as "sealing material" when there is no particular need to distinguish between the resin composition and the sealing material). As high as possible without impairing fluidity and low mold wear,
This is for realizing high thermal conductivity of the sealing material.

The spherical alumina powder used in the present invention comprises:
Mainly particles having a particle diameter range of 1 to 96 μm and an average sphericity of 0.85 or more. Spherical alumina powder is intended to function mainly as a high thermal conductivity imparting material to the sealing material, but in order not to impair the high fluidity and low mold wear of the sealing material, the above-mentioned particle size range and average spherical shape are used. Need to be in the degree.

If the spherical alumina powder contains a large amount of particles having a particle size of more than 96 μm, the fluidity is reduced and the wear of the mold during molding is increased. In the present invention, it is preferable that there are no particles larger than 96 μm. Further, it is preferable that particles having a particle size of less than 1 μm are not present as much as possible in order to exhibit high fluidity, but an amount up to about 3% is acceptable.

When the average sphericity of the spherical alumina powder is less than 0.85, the fluidity of the sealing material decreases, and the amount of mold wear increases. The preferred average sphericity is 0.90 or more.

The spherical silica powder used in the present invention mainly functions to increase the fluidity and reduce the wear of the mold of the sealing material. It is difficult.

In the present invention, when the average particle diameter of the spherical silica powder exceeds 1.0 μm, the fluidity of the sealing material decreases. Further, even if the average sphericity is less than 0.90, the fluidity of the sealing material is impaired, and the amount of mold wear increases. Particularly preferred average sphericity is 0.95 or more, which is larger than the above-mentioned spherical alumina powder. Particularly preferred average particle size is 0.2 to 0.8 μm.

Regarding the composition ratio between the spherical alumina powder and the spherical silica powder, the content of the spherical silica powder in the inorganic powder of the present invention is preferably 3 to 30%, and the balance is preferably substantially spherical alumina powder. If the content of the spherical silica powder is more than 30%, the thermal conductivity of the encapsulant decreases, and if it is less than 3%, the high fluidity is impaired.

When the resin composition of the present invention is used as a sealing material, an inorganic powder substantially composed of the above-mentioned spherical alumina powder and the above-mentioned spherical silica powder is preferable. For example, radiating members used for cooling heat-generating components such as ICs and LSIs may further contain BN powder or the like in order to exhibit flexibility.

The particle size of the powder in the present invention can be measured using a laser diffraction type particle size distribution analyzer.
For the measurement of the spherical alumina powder, for example, a Cirrus granulometer “Model 920” is used, and for the spherical silica powder, for example, a laser diffraction scattering particle size distribution analyzer “LS-230” manufactured by Coulter is used.

The average sphericity is determined by analyzing the particle shape from the projected image of the particle and using the ratio of the projected area to the area of a circle having the same circumference as the projected perimeter of the particle according to the following procedure. can do.

An SE obtained by an electron microscope using a scanning electron microscope (for example, “JSM-T200” manufactured by JEOL Ltd.) and an image analyzer (for example, Nippon Avionics).
It measures by performing image analysis of M photograph. The number of particles measured is 10
0 or more.

First, the projected area (A) and perimeter (P) of a particle
M) is measured. Assuming that the area of a perfect circle corresponding to the perimeter (PM) is (B), the perfectness of the particle is A / B.
Therefore, assuming a perfect circle having the same perimeter as the perimeter (PM) of the sample particles, since PM = 2πr and B = πr ² , B = π × (PM / 2π) ² . Is calculated as A / B = A × 4π / (PM) ² . The roundness of 100 or more particles thus obtained is determined, and the average value is defined as the average sphericity.

The inorganic powder of the present invention is based on the existing thermal spraying technology (for example, “Regarding the thermal spraying and collecting technology for steelmaking furnaces”, Steelmaking Research No. 1982, No. 310), and is based on hydrogen, natural gas, acetylene gas, propane gas, butane. The raw material powder is put into a high-temperature flame formed by a fuel gas such as a fuel gas and an auxiliary gas such as oxygen, and then pyrolyzed and melt-spheroidized to produce a spherical alumina powder and a spherical silica powder, respectively, and then mix them. It can be manufactured by doing.

FIG. 1 shows an example of a schematic diagram of a production process of the spherical alumina powder or the spherical silica powder used in the present invention. FIG. 1 shows a melting furnace 1 provided with a burner 2 capable of injecting raw material powder into a high-temperature flame together with the formation of a high-temperature flame or a high-temperature flame, and a gravitational sedimentation chamber 6 as a collection system for a molten material. , A cyclone 7, and a bag filter 8. Reference numeral 3 denotes a fuel gas supply pipe, 4 denotes an auxiliary combustion gas supply pipe, 5 denotes a raw material powder supply pipe, and 9 denotes a blower. A given product powder can be obtained by on-line classification in the collection system or off-line classification of the collected matter.

As a raw material for producing spherical alumina powder, aluminum hydroxide powder is preferred. Since the particle size of the raw material is largely reflected on the particle size of the product, it is desirable to adjust the particle size of the raw material to the particle size of the product in advance. The aluminum hydroxide powder may be supplied into a high-temperature flame by a dry method or a wet method slurried with water or the like. However, since the average sphericity of the product strongly depends on the flame temperature, supply the aluminum hydroxide powder into a high-temperature flame of 2000 ° C or more as much as possible. Is preferred.

On the other hand, as raw materials for producing spherical silica powder, siliceous raw materials such as quartz and natural silica are used in which the particle ratio of 1 μm or less is 15 to 50% and the particle ratio of 5 μm or more is 50%.
It is preferable to adjust the particle size composition to 〜80% and feed it into a high-temperature flame.

Next, the resin composition of the present invention will be described.

The resin composition of the present invention is obtained by filling the resin with the inorganic powder of the present invention. The filling amount is not particularly limited, but when the use of the resin composition is a sealing material,
In order to achieve high thermal conductivity, high fluidity, and low mold wear, the ratio in the resin composition is 70 to 75 vol. %. If the filling amount is smaller than this, it becomes difficult to exhibit high thermal conductivity, while if it is too large, it leads to a decrease in fluidity and an increase in mold wear.

The resins used in the present invention include epoxy resins, silicone resins, phenolic resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyamides such as polyimide, polyamideimide and polyetherimide, and polybutylene terephthalate. , Polyester such as polyethylene terephthalate, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyether sulfone, polycarbonate,
Maleimide-modified resin, ABS resin, AAS (acrylonitrile-acrylic rubber-styrene) resin, AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin and the like can be mentioned.

Among these, as the resin for the sealing material, an epoxy resin having two or more epoxy groups in one molecule is preferable. Specific examples thereof include phenol novolak type epoxy resin, orthocresol novolak type epoxy resin, epoxidized novolak resin of phenols and aldehydes, glycidyl ethers such as bisphenol A, bisphenol F and bisphenol S,
Glycidyl ester acid epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, alkyl-modified polyfunctional obtained by reaction of polybasic acid such as phthalic acid and dimer acid with epochlorohydrin Epoxy resin, β-naphthol novolak type epoxy resin,
1,6-dihydroxynaphthalene type epoxy resin, 2,
Examples include 7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin, and epoxy resin into which halogen such as bromine is introduced for imparting flame retardancy. Among them, from the viewpoint of moisture resistance and solder reflow resistance, ortho-cresol novolak epoxy resin,
A bishydroxybiphenyl type epoxy resin and an epoxy resin having a naphthalene skeleton are preferable.

The curing agent for the epoxy resin is not particularly limited as long as it cures by reacting with the epoxy resin. For example, phenol, cresol, xylenol,
Novolak type obtained by reacting one or a mixture of two or more selected from the group of resorcinol, chlorophenol, t-butylphenol, nonylphenol, isopropylphenol, octylphenol and the like with formaldehyde, paraformaldehyde or paraxylene under an oxidation catalyst. Resin, polyparahydroxystyrene resin, bisphenol compounds such as bisphenol A and bisphenol S, trifunctional phenols such as pyrogallol and phloroglucinol, acid anhydrides such as maleic anhydride, phthalic anhydride and pyromellitic anhydride, and metaphenylene Examples thereof include aromatic amines such as diamine, diaminophenylmethane, and diaminodiphenylsulfone.

In order to accelerate the reaction between the epoxy resin and the curing agent, a curing accelerator such as 8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, benzyldimethylamine and 2-methylimidazole is used. It is desirable to do. In particular, when high moisture resistance and high-temperature storage stability are required, addition of various ion trapping agents is effective. As the ion trapping agent, Kyowa Chemical's trade names “DHF-4A”, “KW-200”
0 "," KW-2100 ", and the product name" IXE-600 "manufactured by Toagosei Chemical Industry Co., Ltd.

Further, the following components can be added to the resin composition of the present invention as required. That is, as a low-stress agent, silicone rubber, polysulfide rubber, acrylic rubber, butadiene rubber, rubber-like substances such as styrene block copolymers and saturated elastomers, various thermoplastic resins, silicone resins, and even epoxy resins And a resin in which part or all of a phenol resin is modified with amino silicone, epoxy silicone, alkoxy silicone, or the like. As silane coupling agents, epoxy silanes such as γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, aminopropyltriethoxysilane, ureidopropyltriethoxysilane, N -Aminosilanes such as phenylaminopropyltrimethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, hydrophobic silane compounds such as octadecyltrimethoxysilane and mercaptosilane,
Zr chelates, titanate coupling agents, aluminum coupling agents, etc. as surface treatment agents; Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ etc. as flame retardant aids; halogenated epoxy resins as flame retardants Carbon black, iron oxide, dyes, pigments and the like as coloring agents such as phosphorus and phosphorus compounds. Furthermore, natural waxes, synthetic waxes, metal salts of linear fatty acids, acid amides, esters, paraffin, and the like can be blended as release agents.

The resin composition of the present invention is produced by mixing the above-mentioned materials in a blender or a mixer, melt-kneading with a heating roll, a kneader, a single or twin-screw extruder, a Banbury mixer, etc., and pulverizing after cooling. can do.

In order to seal a semiconductor element using the resin composition of the present invention, a molding method such as transfer molding and multi-plunger can be adopted.

[0033]

The present invention will be described more specifically with reference to examples and comparative examples.

Examples 1 to 10 Comparative Examples 1 to 15 Various spherical alumina powders and spherical silica powders were produced using the apparatus shown in FIG.

The spherical alumina powder has a particle diameter of 1 to 200 μm.
m of aluminum hydroxide powder was supplied to a high-temperature flame formed by a fuel gas (LPG) and a combustion-supporting gas (oxygen) while varying its supply amount, and subjected to thermal decomposition and spheroidization. . Eight types of spherical alumina powder (A1 to A8) having various particle diameter ranges by performing classification treatment while adjusting the spheroidization ratio by changing the flame forming conditions and the raw material supply amount
Was manufactured. Table 2 shows the particle size range and the average sphericity.

The spherical silica powder is composed of fuel gas (LPG) 1
0 nm ³ / hr and a high temperature flame formed by the burner air (oxygen) 25Nm ³ / hr, a natural silica rock powder (average particle size 5μ
m) was supplied to perform a spheroidizing treatment, and the powder collected from the cyclone and the bag filter was appropriately classified and mixed to produce ten types of spherical silica powders (S1 to S10). Table 2 shows the average particle size and the average sphericity.

Further, as commercial products, spherical alumina powder "CB grade" (symbol A) manufactured by Showa Denko KK and non-spherical alumina powder "CT4000SG-R" (symbol B) manufactured by Alcoa Chemical Co., Ltd. : 1 was prepared. In addition, crushed silicon nitride powder “SN-F2” (symbol c) manufactured by Denki Kagaku Kogyo Co., Ltd., crushed crystalline silica powder (prepared product) (symbol d), and crushed silica powder “FS-784” manufactured by Denki Kagaku Kogyo Co., Ltd. (symbol) E) is prepared and the average particle size is 15
It was adjusted to μm. They are shown in Table 2.

The powders prepared above were variously combined to form inorganic powders, which were then charged into the resin formulations shown in Table 1 at the ratios shown in Tables 3 and 4 to prepare sealing materials. (1) Thermal conductivity, (2) fluidity, and (3) mold wear of the obtained sealing material were measured in the following manner. Table 5 shows the results.

(1) The thermal conductivity of the sealing material was 28 m in diameter.
After molding into a disk having a thickness of 3 mm and a thickness of 3 mm, it was measured by a temperature gradient method at room temperature using a thermal conductivity measuring device ("ARC-TC-1" manufactured by Agne Co.). EMM using spiral flow mold
I-66 (EpoxyMolding Materialia)
l Institute; Society of Pl
(Actual Industry). The molding temperature is 175 ° C., the molding pressure is 7.4 MPa, and the molding time is 90 seconds. (3) The mold wear was measured by measuring the amount of mass reduction of the disc after 150 cm ^{3 of} a sealing material heated to 175 ° C. was passed through a hole of an aluminum disc having a thickness of 6 mm and a hole diameter of 3 mm.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

As is clear from the table, the sealing material filled with the inorganic powder of the present invention has high thermal conductivity, high fluidity, and low mold wear. That is, when the inorganic powder is 70 to 75 vol. %, And exhibit high fluidity in spite of showing high thermal conductivity, and the amount of mold wear is smaller than when using crystalline silica powder, crushed silica powder, and silicon nitride powder. 1/4 to 1/10
, Which is less than half that of a commercially available spherical alumina powder.

[0046]

According to the present invention, a resin composition such as a sealing material having high thermal conductivity, high fluidity and low mold wear, and an inorganic powder suitable for the production thereof are provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a manufacturing process of a spherical alumina powder or a spherical silica powder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Melting furnace 2 Burner 3 Fuel gas supply pipe 4 Fuel gas supply pipe 5 Raw material powder supply pipe 6 Gravity settling chamber 7 Cyclone 8 Bag filter 9 Blower

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/373 H01L 23/36 MF Term (Reference) 4G072 AA28 AA36 BB07 CC18 GG02 HH20 JJ03 JJ26 MM02 MM28 RR13 TT01 TT02 TT30 UU07 4G076 AA02 AA18 AA24 AB06 AC04 BA06 BC08 CA03 CA26 CA40 DA02 FA01 4J002 AA001 CD001 DE147 DJ016 FD016 FD017 5F036 AA01 BD21 BE01

Claims (2)

[Claims] 1. A spherical silica powder having an average particle diameter of 1.0 μm or less and an average sphericity of 0.90 or more, and particles mainly having a particle diameter range of 1 to 96 μm and an average sphericity of 0.85 μm or less. An inorganic powder comprising the above-mentioned spherical alumina powder and a mixed powder having a spherical silica powder content of 3 to 30%. 2. A resin composition comprising the inorganic powder according to claim 1.