JP2003137627A - Highly thermally conductive inorganic powder, resin composition and surface treatment agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide highly thermally conductive inorganic powder which is used for preparing a resin composition having excellent heat radiation whose viscosity is not easily increased even when highly filled with the powder, and to provide the resin composition obtained by filling the powder into resin, and to provide a surface treatment agent composition used for producing the highly thermally conductive inorganic powder. SOLUTION: The highly thermally conductive inorganic powder consists of inorganic powder having the average grain diameter of 1 to 20 μm, and the maximum grain diameter of <=45 μm. The inorganic powder X being constituting grains of a grain size region of 3 to 40 μm is the spherical one having roundness of >=0.80, and also has a thermal conductivity of >=10 W/mK, and the inorganic powder Y being constituting grains of a grain size region is the spherical or aspherical one having roundness of >=0.30 to <0.80, and also has a thermal conductivity equal to or below that of the inorganic powder X, and in which the mass ratio of X/Y is 1 to 30. The highly thermally conductive inorganic powder may be tread by a surface treatment agent. The resin composition is filled with the highly thermally conductive inorganic powder. The surface treatment agent composition consists of specified two kinds of surface treatment agents.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a high thermal conductive inorganic powder, a resin composition and a surface treatment agent composition. Specifically, an adhesive used in a place where the layer thickness is limited, a high thermal conductive inorganic powder suitable for producing a semiconductor encapsulating material such as underfill, and a resin composition in which the resin is filled. And a surface treating agent composition used for producing a high thermal conductive inorganic powder.

[0002]

2. Description of the Related Art With the miniaturization and higher functionality of electronic devices, the insulating inorganic powders filled in resin compositions used in various parts of electronic parts are becoming finer. For example, in flip chip mounting, which is one of the semiconductor mounting methods, the sealing material (underfill material) used for chip protection is several tens of μm.
An underfill material, which is a liquid epoxy resin filled with fine inorganic powder, is used in order to penetrate into the gap between the substrate and the chip to some extent.

However, when the filling amount of the inorganic powder is large, there is a problem that it is difficult for the inorganic powder to penetrate into the narrow gap and the productivity is extremely deteriorated. In order to solve this, it is necessary to lower the viscosity of the resin composition, and the lower the viscosity, the higher the permeability. Such lowering of viscosity is a common problem not only in underfill materials but also in resins for other uses, and it is considered that the physical properties of the inorganic powder to be filled most affect the viscosity. Japanese Patent Laid-Open No. 2001-200139 discloses that
An inorganic filler for an underfill material is disclosed, and it is said that powder having a particle size of 2 μm or less accounts for 50% or more of the whole inorganic powder. However, if the amount of fine powder is large, the viscosity of the resin composition easily becomes high, and it becomes difficult to achieve high filling.

Furthermore, recently, applications in which heat dissipation is required in addition to insulating properties have appeared, and investigations from both sides of fillers and resins are being promoted. Aluminum nitride, aluminum oxide, crystalline silica and the like have been conventionally known as high thermal conductive inorganic powders, but since they have a crushed shape or a shape without a cut edge (round shape), this is also a resin. The viscosity of the composition cannot be easily increased and highly filled,
As a result, satisfactory heat dissipation cannot be obtained. In addition, these powders abruptly wear the kneader and roll used when mixing with the resin, and the mold used during molding, which deteriorates productivity.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object thereof is to provide a resin composition which does not easily increase in viscosity even when it is highly filled with a resin and has excellent heat dissipation. To provide a high thermal conductive inorganic powder, a resin composition obtained by filling the resin with the high thermal conductive inorganic powder, and a surface treatment agent composition used for producing the high thermal conductive inorganic powder.

[0006]

That is, the present invention is as follows. (Claim 1) The average particle diameter is 1 to 20 μm, and the maximum particle diameter is 4.
The inorganic powder X, which is composed of an inorganic powder of 5 μm or less and has a particle size range of 3 to 40 μm, has a spherical shape with a roundness of 0.80 or more and a thermal conductivity of 10 W / mK or more, and has a particle size range of 0.1 The roundness of the inorganic powder Y that is a constituent particle of 1.5 μm is 0.30 or more and less than 0.80, and the thermal conductivity is equal to or less than that of the inorganic powder X. The mass ratio of X / Y is Is 1 to 30. Highly thermally conductive inorganic powder. (Claim 2) The inorganic powder X is an aluminum oxide powder, and the inorganic powder Y is an aluminum oxide powder and / or a silica powder. (Claim 3) A surface treatment is applied with one or more surface treatment agents A selected from silane coupling agents, titanate coupling agents and aluminate coupling agents. The high thermal conductivity inorganic powder according to claim 1 or 2. (Claim 4) A surface treatment agent B of a polycarboxylic acid type surfactant and / or a polyacrylic acid type surfactant has been subjected to a surface treatment. High thermal conductivity inorganic powder. (Claim 5) A resin composition comprising the high thermal conductive powder according to claim 1, 2, 3 or 4. (Claim 6) One or more surface treatment agents A selected from a silane coupling agent, a titanate coupling agent and an aluminate coupling agent, and a polycarboxylic acid type surfactant and / or poly A surface-treating agent composition of high thermal conductive inorganic powder, characterized in that the surface-treating agent B of an acrylic acid type surfactant is contained in a mass ratio of B / A of 1 to 30.

[0007]

The present invention will be described in more detail below.

The first condition is that the high thermal conductivity inorganic powder of the present invention has an average particle size of 1 to 20 μm and a maximum particle size of 45 μm or less. If the average particle size is less than 1 μm, the thermal conductivity will be remarkably reduced, and if it is more than 20 μm, the mixer, the mold and the like will be abraded, resulting in a decrease in productivity. When the maximum particle size is larger than 45 μm, not only the viscosity of the resin composition is easily increased, but also coarse particles are clogged in the narrow gap, which impedes the penetration of the resin composition and limits the use. here,
The maximum particle size is 0.5 mass% of the residual amount remaining on the screen by the water sieving method.
Means a particle size of less than.

The high thermal conductivity inorganic powder of the present invention has a particle size structure similar to that of a mixture of two or more kinds of powders having different roundness depending on the particle size range. However, it may be a mixture thereof. That is, the high thermal conductive inorganic powder of the present invention contains the inorganic powder X and the inorganic powder Y, and the roundness of the inorganic powder X, which is a constituent particle in the particle size range of 3 to 40 μm, is spherical and has a heat of 0.80 or more. Conductivity 10W /
Inorganic powder Y, which is a constituent particle having a particle size range of 0.1 to 1.5 μm, having a circularity of 0.30 or more and less than 0.80, is spherical or non-spherical, and has the same thermal conductivity as inorganic powder X. The second condition is that they are equal or less.

In the present invention, the inorganic powder X is added in the particle size range of 3 to 3.
The reason why 40 μm and the inorganic powder Y are selected in the particle size range of 0.1 to 1.5 μm is that, as a result of many experiments, the viscosity and the thermal conductivity of the resin composition are the best by controlling the powder in these particle size ranges. It depends on having discovered that. In addition, when the roundness of the inorganic powder X is less than 0.80, this inorganic powder has the greatest effect on the viscosity of the resin composition. Filling becomes difficult. Further, if the thermal conductivity is less than 10 W / mK, it is not possible to impart sufficiently high heat dissipation characteristics to the resin composition. On the other hand, the inorganic powder Y does not significantly affect the thermal conductivity of the resin composition, but has the effect of entering between the inorganic powders X to promote the heat path. Therefore, if the roundness is less than 0.30, it becomes difficult to enter between the inorganic powders X, and if it is 0.8 or more, the number of contact points with the inorganic powders X decreases, and the heat path promoting effect also decreases. I will end up. Further, even if the thermal conductivity of the inorganic powder X exceeds that of the inorganic powder X, the thermal conductivity of the resin composition is greatly affected by the inorganic powder X, so the thermal conductivity does not improve so much. It is possible to use a powder having a higher thermal conductivity than that of the inorganic powder X, but it is meaningless to use a relatively expensive powder having a high thermal conductivity.

Here, the roundness can be measured using a scanning electron microscope ("JXA-8600M" manufactured by JEOL Ltd.) and an image analyzer (manufactured by Japan Avionics). That is, the projected area (A) and the perimeter (PM) of the particles are measured from the SEM photograph of the powder. When the area of a perfect circle corresponding to the perimeter (PM) is (B), the roundness of the particle is expressed as A / B. Therefore, assuming a perfect circle with the same perimeter as the perimeter (PM) of the sample particles, PM
= 2πr and B = πr ² , B = π × (PM / 2
π) ² and the roundness of this particle is roundness = A / B =
It can be calculated as A × 4π / (PM) ² . Therefore, in the present invention, an arbitrary 100 particles are measured, and the average value thereof is used as the roundness of the powder.

Specific examples of the inorganic powder X are powders of aluminum oxide, zinc oxide, aluminum nitride, silicon nitride, boron nitride and the like, but aluminum oxide powder is most suitable from the viewpoint of chemical stability and thermal conductivity. . On the other hand, inorganic powder Y
Specific examples of crystalline silica, fused (amorphous) silica, calcium carbonate, aluminum oxide, aluminum hydroxide,
The powder is aluminum nitride, boron nitride, silicon nitride, or the like, and when the inorganic powder X is an aluminum oxide powder, it is one or a combination of crystalline silica powder, fused (amorphous) silica powder, and aluminum oxide powder. Is best.

The third condition of the high thermal conductive inorganic powder of the present invention is that the ratio of the inorganic powder X and the inorganic powder Y is 1 to 30 in terms of mass ratio X / Y. Inorganic powder Y is inorganic powder X
It promotes the low viscosity of the resin composition and enables the resin to be highly filled. If the X / Y ratio is less than 1, the proportion of the fine powder region is too small, and the resin composition easily becomes highly viscous, and if it exceeds 30, the effect of imparting thermal conductivity remarkably deteriorates. The high thermal conductivity inorganic powder of the present invention is preferably configured such that the total of the inorganic powder X and the inorganic powder Y is 60% or more (including 100%), and when the total is less than 100%, the balance is It is preferable that the spherical inorganic powder has a roundness of 0.80 or more and a diameter of 1.5 to 3 μm.

Next, another invention will be described. These inventions are high thermal conductivity inorganic powders capable of further improving the thermal conductivity of the resin composition, and the high thermal conductivity inorganic powders of the present invention (hereinafter, "high thermal conductivity inorganic powder base material").
Also called. ) Is related to the improvement.

The first is to surface a high thermal conductive inorganic powder base material with one or more surface treatment agents A selected from silane coupling agents, titanate coupling agents and aluminate coupling agents. The treated high thermal conductive inorganic powder (hereinafter, also referred to as “high thermal conductive inorganic powder A”).
Is. By using this, the adhesiveness with the resin is further enhanced, the interfacial thermal resistance between the high thermal conductive inorganic powder A and the resin is lowered, and further high thermal conductivity can be imparted. As the surface treatment agent A, a silane coupling agent is preferable from the viewpoint of reactivity with the high thermal conductivity inorganic powder base material.

Examples of silane coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and β (3,4 epoxy synchrohexyl).
Ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycyrimethoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ- Aminopropylmethyldimethoxysilane, γ-
Aminopropyltriethoxysilane, N-phenyl-γ
-Aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane and the like, and one or more of these may be used.

The surface treatment of the highly heat-conductive inorganic powder base material with the surface treatment agent A is carried out by a spray method using a fluid nozzle, agitating with shearing force, a dry method such as a ball mill or a mixer,
A wet method such as an aqueous method or an organic solvent method can be adopted. It should be noted that the shearing force is set so that the high thermal conductivity inorganic powder base material is not broken.

The in-system temperature in the dry method or the drying temperature after the treatment in the wet method is appropriately determined depending on the kind of the surface treating agent A in a region where it is not thermally decomposed. For example, the temperature in the case of γ-aminopropyltriethoxysilane is 8
0-150 degreeC is desirable.

The second reason is that when the resin composition has a low viscosity like an underfill material, the high thermal conductivity inorganic powder does not settle and the thermal conductivity of the resin composition is not impaired. The high thermal conductivity inorganic powder base material or the high thermal conductivity inorganic powder A is surface-treated with one or more surface treatment agents B selected from acid-based surfactants and polyacrylic acid-based surfactants. High thermal conductivity inorganic powder (hereinafter, both are collectively referred to as "high thermal conductivity inorganic powder B". Further, the treated powder by the former is "high thermal conductive inorganic powder b1", and the treated powder by the latter is "high thermal conductive inorganic powder B1". Powder b
Also called 2 ". ).

The surface treatment of the high thermal conductivity inorganic powder base material or the high thermal conductivity inorganic powder A with the surface treatment agent B is carried out according to the treatment method of the surface treatment agent A.
It should be noted that the treatment must be performed at a temperature at which thermal decomposition of the surface treatment agent B does not occur, as in the case of.

In the present invention, the treatment with the surface-treating agent A and the treatment with the surface-treating agent B may be either one or both. By both treatments, it is possible to simultaneously improve the adhesion to the resin and prevent the high heat conductive inorganic powder from settling, and improve the heat dissipation of the resin composition.

Further, in the case of both the treatments with the surface treatment agent A and the surface treatment agent B, the treatments may be carried out separately or simultaneously. Therefore, it is desirable in terms of handling that the surface treatment agent A and the surface treatment agent B are premixed surface treatment agent compositions, and the mixing ratio thereof is 1 in terms of the surface treatment agent B / surface treatment agent A mass ratio. It is preferably -30. If the ratio is less than 1, the viscosity of the resin composition is increased by an excessive amount of the surface treatment agent A, and a sufficient sedimentation preventing effect due to the lack of the surface treatment agent B cannot be obtained. On the other hand, when the ratio exceeds 30, the excessive surface treatment agent B fills the adsorption site on the surface of the surface treatment agent A of the high thermal conductive inorganic powder, and the unreacted amount of the surface treatment agent A increases, and Adhesion is not sufficiently improved.

The resin composition of the present invention comprises the above-mentioned high thermal conductive inorganic powder of the present invention, that is, a high thermal conductive inorganic powder base material, a high thermal conductive inorganic powder A, a high thermal conductive inorganic powder B (that is, a high thermal conductive inorganic powder). Powder b1, highly conductive inorganic powder b
Any one of 2) or a mixture of two or more thereof is prepared. The filling amount is 50 to 95 depending on the use.
Mass% is common.

Examples of resins include epoxy resins, silicone resins, phenol resins, melamine resins, urea resins, unsaturated polyesters, fluororesins, polyimides, polyamides such as polyamideimide and polyetherimide, and polyesters such as polybutylene terephthalate and polyethylene terephthalate. , Polyphenylene ether, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyether sulfone, polycarbonate, maleimide modified resin, ABS resin, AAS (acrylonitrile-acrylic rubber / styrene) resin, AE
S (acrylonitrile / ethylene / propylene / diene rubber-styrene) resin or the like is used.

When the resin composition is a liquid resin composition such as an underfill material, a liquid epoxy resin is used as the resin. As the liquid epoxy resin, any epoxy resin having two or more epoxy groups in one molecule can be used. Specific examples thereof include phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, epoxidized novolac resins of phenols and aldehydes, glycidyl ethers such as bisphenol A, bisphenol F and bisphenol S, phthalic acid and Glycidyl ester acid epoxy resin obtained by reaction of polybasic acid such as dimer acid and epochlorohydrin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, alkyl-modified polyfunctional epoxy resin, β-naphthol novolac type Eoxy resin, 1,6-dihydroxynaphthalene type epoxy resin, 2,7-dihydroxynaphthalene type epoxy resin, bishydroxybiphenyl type epoxy resin,
Further, it is an epoxy resin or the like into which halogen such as bromine is introduced in order to impart flame retardancy. Of these, epoxy resins that are liquid at room temperature are preferably used, and bisphenol-type epoxy resins such as bisphenol A-type epoxy resins and bisphenol F-type epoxy resins, alicyclic epoxy resins, and the like can be mentioned. The above is used.

The curing agent for the liquid epoxy resin is not particularly limited as long as it cures by reacting with the liquid epoxy resin, and examples thereof include phenol, cresol, xylenol, resorcinol, chlorophenol, t-butylphenol, nonylphenol and isopropyl. Novolak type resins, polyparahydroxystyrene resins, bisphenol A and bisphenol obtained by reacting one or a mixture of two or more selected from the group consisting of phenol and octylphenol with formaldehyde, paraformaldehyde or paraxylene under an oxidation catalyst. Bisphenol compounds such as S, trifunctional phenols such as pyrogallol and phloroglucinol, maleic anhydride, acid anhydrides such as phthalic anhydride and pyromellitic anhydride, metaphenylenediamine, dia Bruno diphenylmethane, aromatic amines such as diaminodiphenyl sulfone, and the like.

The resin composition of the present invention may contain the following components if necessary. That is, as a stress reducing agent, a rubber-like substance such as silicone rubber, polysulfide rubber, acrylic rubber, butadiene rubber, styrene block copolymer or saturated elastomer, various thermoplastic resins, resinous substances such as silicone resin, Is a resin obtained by modifying a part or all of an epoxy resin, a phenolic resin with an aminosilicone, an epoxysilicone, an alkoxysilicone, etc., as a silane coupling agent, γ-glycidoxypropyltrimethoxysilane, β
-Epoxysilanes such as (3,4-epoxycyclohexyl) ethyltrimethoxysilane, aminopropyltriethoxysilane, ureidopropyltriethoxysilane,
Aminosilane such as N-phenylaminopropyltrimethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, hydrophobic silane compound such as octadecyltrimethoxysilane, mercaptosilane, and the like, Zr chelate, titanate coupling agent as a surface treatment agent,
As flame retardant aids such as aluminum-based coupling agents,
Flame retardants such as Sb ₂ O ₃ , Sb ₂ O ₄ , and Sb ₂ O ₅ are halogenated epoxy resins and phosphorus compounds, and colorants are carbon black, iron oxide, dyes, pigments, and the like.

A curing accelerator can be added to the resin composition of the present invention in order to accelerate the reaction between the epoxy resin and the curing agent. Examples of the curing accelerator include 1,8-diazabicyclo (5,4,0) undecene-7, triphenylphosphine, benzyldimethylamine, 2-methylimidazole and the like.

The resin composition of the present invention can be produced by stirring, dissolving, mixing and dispersing predetermined amounts of the above materials. The apparatus for mixing, stirring, dispersing, etc. of these mixtures is not particularly limited, but a Leiki machine equipped with a stirring and heating device, three rolls, a ball mill, a planetary mixer and the like can be used. Also, these devices may be used in an appropriate combination.

When the resin composition of the present invention is used as an underfill material, the temperature at which it is permeated into the gap between the semiconductor chip and the substrate for sealing is preferably 60 to 120 ° C.

[0031]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples.

Examples 1 to 7 Comparative Examples 1 to 6 Inorganic powders 1 to 13 shown in Table 1 were prepared and mixed in a composition as shown in Table 2 to obtain a high thermal conductivity inorganic powder base material a to e ( Examples 1 to 5) and Chi-wa (Comparative Examples 1 to 6) were adjusted. Their powder properties are shown in Table 4. Further, the high thermal conductive inorganic powder F (Example 6) and the high thermal conductive inorganic powder G (Example 7) were prepared by subjecting the high thermal conductive inorganic powder base material (i) to a surface treatment according to the following. A and high thermal conductivity inorganic powder b1.

In a 10 liter container having a ball diameter of 20 mm and a ball filling rate of 50% by volume, 1 kg of a highly heat-conductive inorganic powder base material (i) and the surface treatment agent A or the surface treatment agent B shown in Table 3 were charged at room temperature, It was operated at a speed of once / second for 1 hour under normal pressure conditions, and dried at 120 ° C. for 1 hour to obtain high heat conductive inorganic powder F and F.

The respective materials were mixed in the proportions shown in Table 5, and the high thermal conductive inorganic powders (i) to (i) were mixed in the proportion of 75% by mass in terms of the inorganic powder to prepare a resin composition. The viscosity, the thermal conductivity, and the amount of wear of this were measured according to the following. The results are shown in Table 6.

(1) Viscosity An E-type viscometer type (“EHD viscometer” manufactured by Tokyo Keiki Co., Ltd.) was used to measure viscosity at a temperature of 40 ° C. and a rotation speed of 10 rpm.

(2) Thermal conductivity The resin composition was poured into a mold provided with a disk-shaped hole having a diameter of 28 mm and a thickness of 3 mm, degassed and molded at 150 ° C. for 20 minutes. Thermal conductivity measuring device ("ARC-T" manufactured by Agne Co.
C-1 type ") and was measured by a temperature gradient method at room temperature.

[0037] (3) wear amount thickness 6 mm, the weight loss of the disc after the resin composition was 300 mm ³ to pass through the pores of an aluminum disc having a pore diameter of 3mm was evaluated as the wear amount.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[0043]

[Table 6]

As is clear from Tables 1 to 6, the resin composition using the high thermal conductive inorganic powder of the present invention is superior to the comparative example in all of viscosity, thermal conductivity and wear resistance. I understand.

Examples 8 and 9 Tests were carried out using a surface treatment agent composition comprising surface treatment agent A and surface treatment agent B. That is, high thermal conductivity inorganic powder base material a, surface treatment agent A: silane coupling agent (trade name: KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.), surface treatment agent B: polycarboxylic acid type surfactant (trade name: Japan The test was carried out using Marinim AKM-0531 manufactured by Yushi Co., Ltd.

The surface treatment method was as follows: 1 kg of the highly heat-conductive inorganic powder base material (1 kg) in a 10 liter container having a ball diameter of 20 mm and a ball filling rate of 50% by volume, and the surface treatment agent composition in terms of mass of the surface treatment A of 0. After charging at 36 g and operating at room temperature and atmospheric pressure at a speed of once per second for 1 hour,
It was dried at 20 ° C. for 1 hour to obtain a high thermal conductive inorganic powder b2. The results are shown in Table 7.

[0047]

[Table 7]

As is clear from Table 7, the surface treatment agent A
It can be seen that even the surface treatment agent composition comprising a mixture of the resin and the surface treatment agent B has a sufficiently high thermal conductivity of the resin composition.

[0049]

EFFECTS OF THE INVENTION According to the present invention, a highly heat-conductive inorganic powder capable of preparing a resin composition which does not easily become highly viscous even when highly filled with a resin and has excellent heat dissipation, and There is provided a resin composition in which a resin is filled with a resin, and a surface treatment agent composition used for producing a high thermal conductive inorganic powder.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 3/22 C08K 3/22 3/36 3/36 7/16 7/16 9/04 9/04 C08L 101/00 C08L 101/00 C09C 1/28 C09C 1/28 1/40 1/40 3/06 3/06 3/10 3/10 3/12 3/12 F term (reference) 4G012 LA01 LA14 4J002 AA001 BD121 BG041 BN061 BN071 BN151 CC041 CC161 CC181 CD001 CD011 CD021 CD031 CD051 CD061 CD121 CF001 CF061 CF071 CF161 CF211 CG001 CH071 CL001 CM041 CN011 CN031 CP031 DE146 DJ016 FB086 FB096 CB11 CB37 FD37 FB16 FD200 FB16 FD16A FD166 FB16 FD16A FD166 FD166 FD166 FD166 AFD FF13

Claims (6)

[Claims] 1. An inorganic powder having an average particle size of 1 to 20 μm and a maximum particle size of 45 μm or less, and having a particle size range of 3 to 40 μm.
The roundness of the inorganic powder X, which is the constituent particle, is 0.80 or more, and the thermal conductivity is 10 W / mK or more, and the trueness of the inorganic powder Y, which is the constituent particle in the particle size range of 0.1 to 1.5 μm. High thermal conductivity, which is spherical or non-spherical with a circularity of 0.30 or more and less than 0.80, has a thermal conductivity equal to or less than that of the inorganic powder X, and has an X / Y mass ratio of 1 to 30. Inorganic powder. 2. The high thermal conductive inorganic powder according to claim 1, wherein the inorganic powder X is an aluminum oxide powder and the inorganic powder Y is an aluminum oxide powder and / or a silica powder. 3. A surface treatment with one or more surface treatment agents A selected from a silane coupling agent, a titanate coupling agent and an aluminate coupling agent. The high thermal conductivity inorganic powder according to claim 1 or 2. 4. The surface treatment is applied with a surface treatment agent B of a polycarboxylic acid type surfactant and / or a polyacrylic acid type surfactant, and the surface treatment is performed.
The high thermal conductive inorganic powder described. 5. A resin composition comprising the high thermal conductive powder according to claim 1, 2, 3 or 4 filled therein. 6. One or more surface treatment agents A selected from a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent, and a polycarboxylic acid type surfactant and / or poly A surface-treating agent composition for a high thermal conductive inorganic powder, characterized by comprising a surface-treating agent B of an acrylic acid-based surfactant in a mass ratio of B / A of 1 to 30.