Thermally conductive silicone composition, method for producing the same, and semiconductor device

Abstract

Disclosed is a thermally conductive silicone composition comprising: (A) a hydrolyzable organopolysiloxane having an alkoxysilyl group; 50 to 70% by volume of (B) aluminum nitride particles having an average particle diameter of 0.5 μm or more and 2.0 μm or less, and a content of coarse powder having a particle diameter of 10 μm or more in the particles obtained by laser diffraction type particle size distribution measurement of 1.0% by volume or less of the whole, the thermally conductive silicone composition having a thermal conductivity of 1.3 W / mK or more by the transient plane source method. By the present invention, a thermally conductive silicone composition having a high thermal conductivity and being compressible to 10 μm or less, and a method for producing the same can be provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a heat conductive silicone composition. In detail, the present application relates to a heat conductive silicone composition which can effectively cool electronic devices, a method for producing the same, and a semiconductor device. BACKGROUND

[0002] It is widely known that electronic devices generate heat during use and that the performance is reduced due to this. As a means for solving this problem, various heat dissipation techniques have been employed. Generally, a cooling member (heat sink or the like) is disposed in the vicinity of the heat generating portion and the two are brought into close contact, and on this basis, heat is effectively removed through the cooling member, thereby dissipating heat. At this time, if there is a gap between the heat generating member and the cooling member, air having poor heat conductivity will be present, thereby causing an increase in thermal resistance and the temperature of the heat generating member cannot be sufficiently reduced. In order to prevent such a phenomenon, a heat dissipation material having good heat conductivity and followability to the surface of the member, such as a liquid heat dissipation material or a heat dissipation sheet, is used. In particular, depending on the device, the gap can be very narrow, 10 μm or less, and therefore a liquid heat dissipation material which can be compressed to 10 μm or less is used (Patent Documents 1 to 13).

[0003] Furthermore, in most cases, an electrically insulating state must be ensured between the heat generating portion and the cooling member, and therefore the insulating property is sometimes required of the heat conductive material. At this time, as a heat conductive filler, metal particles such as aluminum or copper, silver or the like cannot be used, and an insulating heat conductive filler such as aluminum hydroxide, alumina (aluminum oxide) or the like is mostly used. Since the heat conductivity of aluminum hydroxide and alumina is low in itself, if such a heat conductive filler is used to obtain a heat conductive material having high heat conductivity, a large amount of the filler must be filled. As a result, problems such as the viscosity of the heat conductive material becoming very high and being difficult to apply, and being unable to be sufficiently compressed, arise (Patent Documents 14 and 15).

[0004] Further, it is known that the heat generating portion and the cooling member are repeatedly subjected to heating and cooling, and therefore the member is repeatedly thermally shrunk. Due to this, the oil component of the heat conductive silicone composition and the heat conductive filler are separated. Furthermore, phenomena such as pump-out in which the heat conductive composition is squeezed out from between the heat generating portion and the cooling member, occur. As a result, the thermal resistance rises and the heat generating portion cannot be effectively cooled. In order to prevent such a phenomenon, a method in which a tackifier is added to increase the viscosity of the heat conductive silicone composition has been proposed. However, problems such as the viscosity becoming very high and being difficult to apply arise (Patent Document 16).

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent No. 2938428

[0008] Patent Literature 2: Japanese Patent No. 2938429

[0009] Patent Literature 3: Japanese Patent No. 3580366

[0010] Patent Literature 4: Japanese Patent No. 3952184

[0011] Patent Literature 5: Japanese Patent No. 4572243

[0012] Patent Literature 6: Japanese Patent No. 4656340

[0013] Patent Literature 7: Japanese Patent No. 4913874

[0014] Patent Literature 8: Japanese Patent No. 4917380

[0015] Patent Literature 9: Japanese Patent No. 4933094

[0016] Patent Literature 10: Japanese Patent Application Publication No. 2008-260798

[0017] Patent Literature 11: Japanese Patent Application Publication No. 2009-209165

[0018] Patent Literature 12: Japanese Patent Application Publication No. 2012-102283

[0019] Patent Literature 13: Japanese Patent Application Publication No. 2012-96361

[0020] Patent Literature 14: Japanese Patent Application Publication No. 2017-226724

[0021] Patent Literature 15: Japanese Patent Application Publication No. 2017-210518

[0022] Patent Literature 16: Japanese Patent Application Publication No. 2004-91743 SUMMARY

[0023] Technical Problem to be Solved by the Invention

[0024] As described above, development of a heat-conductive silicone composition that can balance high heat conductivity and compressibility to 10 μm or less is sought. The present invention was made in view of the above-described circumstances, and aims to provide a heat-conductive silicone composition that has high heat conductivity and can be compressed to 10 μm or less, and a method for producing the same, compared to conventional heat-conductive silicone compositions.

[0025] Technical Means for Solving the Technical Problem

[0026] In order to solve the above technical problems, the present invention provides a thermally conductive silicone composition comprising the following components (A) and (B):

[0027] (A) a hydrolyzable organopolysiloxane having an alkoxysilyl group;

[0028] 50 to 70% by volume of (B) aluminum nitride particles having an average particle size of 0.5 μm to 2.0 μm, wherein the content of coarse powder having a particle size of 10 μm or greater in the particles as determined by laser diffraction particle size distribution measurement is 1.0% or less by volume of the entire particles;

[0029] The thermal conductivity of the thermally conductive silicone composition is greater than 1.3 W / mK using a transient planar heat source method (Hot Disk).

[0030] Compared with conventional thermally conductive silicone compositions, the thermally conductive silicone composition has high thermal conductivity and good compressibility when compressed to a thickness of 10 μm or less.

[0031] The aluminum nitride particles preferably have an oxygen content of 1.0 mass % or less.

[0032] When the oxygen content is equal to or less than a predetermined value, the thermal conductivity of the thermally conductive silicone composition becomes further increased.

[0033] Preferably, the thermal resistance of the thermally conductive silicone composition measured by the laser flash method at 25°C is 5.0 mm 2 ·K / W or less

[0034] When the thermal resistance is equal to or less than a predetermined value, the thermal conductivity of the thermally conductive silicone composition becomes further increased.

[0035] Preferably, the thermally conductive silicone composition has a shear rate of 6S at 25°C as measured by a spiral viscometer. -1 The absolute viscosity is 3 to 500 Pa·S.

[0036] When the absolute viscosity is within the above-specified range, the thermally conductive silicone composition can be easily maintained in shape and easily sprayed, resulting in good workability.

[0037] The present invention also provides a semiconductor device in which the thermally conductive silicone composition is present in a gap having a thickness of 10 μm or less formed between a heating element and a cooling element.

[0038] The semiconductor device has high cooling performance because a thermally conductive silicone composition having a higher thermal conductivity than conventional thermally conductive silicone compositions and having good compressibility compressed to a thickness of less than 10 μm exists in a narrow gap formed between a heating element and a cooling element.

[0039] Preferably, the heat generating body is an insulated gate bipolar transistor (IGBT).

[0040] If the heat generating body is an IGBT, the IGBT can be effectively cooled in the semiconductor device.

[0041] Further, the present application provides a production method of the heat conductive silicone composition, which includes a step of mixing the (A) component and the (B) component at a temperature of 100°C or higher for 30 minutes or more.

[0042] By the production method, a heat conductive silicone composition having a high thermal conductivity and a good compressibility of being compressed to 10 μm or less can be produced compared to conventional heat conductive silicone compositions.

[0043] Effects of the Invention

[0044] According to the present application, a heat conductive silicone composition having a high thermal conductivity and a good compressibility of being compressed to 10 μm or less can be obtained compared to conventional heat conductive silicone compositions. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 FIG. 1 is a cross-sectional view showing one example of a semiconductor device in which the heat conductive silicone composition of the present application exists in a gap between an insulated gate bipolar transistor and a cooling fin. DETAILED DESCRIPTION

[0046] As described above, development of a silicone composition having a high thermal conductivity and a good compressibility of being compressed to 10 μm or less has been sought.

[0047] The present inventors have repeatedly and earnestly researched the above technical problem, and as a result, have found that a silicone composition containing a hydrolyzable organopolysiloxane having an alkoxysilyl group and aluminum nitride, which has a high thermal conductivity and a good compressibility of being compressed to 10 μm or less compared to conventional silicone compositions, and the average particle diameter of the aluminum nitride is within a specific range and the content of coarse powder is small, thereby completing the present application.

[0048] That is, the present application discloses a heat conductive silicone composition containing the following (A) component and (B) component:

[0049] (A) a hydrolyzable organopolysiloxane having an alkoxysilyl group;

[0050] 50 to 70 vol% of (B) aluminum nitride particles having an average particle diameter of 0.5 μm or more and 2.0 μm or less, and a content of coarse powder having a particle diameter of 10 μm or more in particles obtained by a laser diffraction type particle size distribution measuring method of 1.0 vol% or less of the whole.

[0051] The heat conductive silicone composition has a thermal conductivity of 1.3 W / mK or more using a transient plane source method.

[0052] Hereinafter, the present application will be described in detail.

[0053] [(A) component]

[0054] The (A) component is a hydrolyzable organopolysiloxane having an alkoxysilyl group. The (A) component can function as a surface treatment agent for the thermally conductive filler of the (B) component described below. Therefore, the interaction of the (A) component and the thermally conductive filler of the (B) component is strengthened. As a result, even if a large amount of the thermally conductive filler of the (B) component is filled in the heat conductive silicone composition, the heat conductive silicone composition can maintain flowability. At the same time, it is also possible to suppress the decrease in heat dissipation performance caused by oil separation or bleeding over time. As the (A) component, an organopolysiloxane represented by the following general formula (1), for example, can be cited. Among them, a hydrolyzable organopolysiloxane containing a trifunctionality is preferred.

[0055] [Chemical Formula 1]

[0056]

[0057] In the formula, R 1 is independently an unsubstituted or substituted monovalent hydrocarbon group. X 1 , X 2 , X 3 is R 1 or -(R 2 ) n -SiR 3 g (OR 4 ) 3-g represents a group represented by the formula -(R 2 ) n -SiR 3 g (OR 4 ) 3-g . R 2 is an oxygen atom or an alkylene group having 1 to 4 carbon atoms, R 3 is independently an unsubstituted or substituted monovalent hydrocarbon group, R 4 is independently an alkyl group, an alkoxyalkyl group, an alkenyl group, or an acyl group having 1 to 4 carbon atoms, n is 0 or 1, and g is an integer of 0 to 2. a and b are respectively 1≤a≤1000 and 0≤b≤1000.

[0058] In the formula (1), R 1It is independently an unsubstituted or substituted monovalent hydrocarbon group, preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3 carbon atoms. Examples thereof include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups. Examples of linear alkyl groups include methyl groups, ethyl groups, propyl groups, hexyl groups, and octyl groups. Examples of branched alkyl groups include isopropyl groups, isobutyl groups, tert-butyl groups, and 2-ethylhexyl groups. Examples of cyclic alkyl groups include cyclopentyl groups and cyclohexyl groups. Examples of alkenyl groups include vinyl groups and allyl groups. Examples of aryl groups include phenyl groups and tolyl groups. Examples of aralkyl groups include 2-phenylethyl groups and 2-methyl-2-phenylethyl groups. Examples of halogenated alkyl groups include 3,3,3-trifluoropropyl groups, 2-(nonafluorobutyl)ethyl groups, and 2-(heptadecafluorooctyl)ethyl groups. As R 1 , preferably methyl, phenyl, or vinyl.

[0059] As R 2 The alkylene group having 1 to 4 carbon atoms includes, for example, methylene, ethylene, propylene, and butylene. 3 Each of the unsubstituted or substituted monovalent hydrocarbon groups is independently free of aliphatic unsaturated bonds, and is preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. Examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenyl; aralkyl groups such as benzyl, phenethyl, phenylpropyl, and methylbenzyl; and groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms such as fluorine, chlorine, and bromine, or with cyano groups.

[0060] The above R 4 are independently an alkyl group, an alkoxyalkyl group, an alkenyl group, or an acyl group having 1 to 4 carbon atoms. 4 The alkyl group of R 1 The same alkyl groups as those exemplified in the above are alkyl groups having 1 to 4 carbon atoms. Examples of the alkoxyalkyl group include methoxyethyl and methoxypropyl. 4 The acyl group is preferably an acyl group having 2 to 8 carbon atoms, and examples thereof include acetyl and octanoyl. 4 An alkyl group is preferred, and a methyl group and an ethyl group are particularly preferred.

[0061] a and b are as described above, preferably a+b is 10 to 1000, more preferably 10 to 300. n is 0 or 1, g is an integer of 0 to 2, preferably 0. In addition, it is preferred that the molecule contain 1 to 6 OR 4group, particularly preferably having 3 or 6 OR 4 In addition, the bonding order of each siloxane unit shown in the brackets is not limited to the following.

[0062] Preferred specific examples of the component (A) include the following.

[0063] [Chemical Formula 2]

[0064]

[0065] Component (A) is the main component of the thermally conductive silicone composition. Its blending amount is preferably 30-50% by volume, more preferably 40-50% by volume, of the thermally conductive silicone composition. Including component (A) within this range maintains good compressibility and prevents degradation of thermal resistance due to oil separation or extraction. Component (A) may be blended singly or in combination of two or more.

[0066] [(B) ingredient]

[0067] The thermally conductive silicone composition of the present invention contains (B) aluminum nitride particles as a thermally conductive filler. Aluminum nitride has a higher thermal conductivity than alumina. Therefore, a thermally conductive silicone composition with high thermal conductivity can be obtained with a smaller amount than aluminum oxide. The average particle size of the aluminum nitride particles of component (B) is not less than 0.5 μm and not more than 2.0 μm, preferably not less than 0.5 μm and not more than 1.5 μm. If the average particle size of the aluminum nitride particles (B) exceeds 2.0 μm, the compressibility of the thermally conductive silicone composition obtained will be significantly deteriorated. In addition, if the average particle size of the aluminum nitride particles (B) is less than 0.5 μm, the viscosity of the thermally conductive silicone composition will be significantly increased.

[0068] The average particle size is the volume average particle size (cumulative average diameter D) obtained by Microtrac (laser diffraction scattering method). 50 (median diameter)) can be measured using, for example, Microtrac MT3300EX manufactured by Nikkiso Co., Ltd.

[0069] The content of coarse powder with a particle size of 10 μm or greater in the aluminum nitride particles of component (B) is 1.0% by volume or less. If the content of this coarse powder exceeds 1.0% by volume, the thickness of the thermally conductive silicone composition cannot be reduced to 10 μm or less when compressed. While there is no particular lower limit, the content of this coarse powder can be set to, for example, 0.001% by volume or greater, based on the technical detection limit. The coarse powder in the aluminum nitride particles is preferably as small as possible, with a particle size of 12 μm or less.

[0070] The content of the coarse powder can be measured using, for example, Microtrac MT3300EX manufactured by Nikkiso Co., Ltd.

[0071] The thermally conductive silicone composition of the present invention comprises 50-70 volume percent of (B) aluminum nitride particles. If the content of (B) aluminum nitride particles is less than 50 volume percent, the thermal conductivity of the thermally conductive silicone composition decreases; if the content exceeds 70 volume percent, the thermally conductive silicone composition may not be uniform.

[0072] The oxygen content of the aluminum nitride particles in component (B) is preferably 1.0% by mass or less, more preferably 0.5% by mass or less. Using aluminum nitride particles with an oxygen content of 1.0% by mass or less as component (B) can improve the thermal conductivity of the thermally conductive silicone composition. The lower limit of the oxygen content is not particularly limited; for example, it can be 0.13% by mass. The oxygen content can be measured using an ENGA-120 manufactured by HORIBA, Ltd.

[0073] The aluminum nitride particles of component (B) can be produced by either direct nitridation or reduction nitridation, but reduction nitridation is preferred. This is because the direct nitridation method includes a crushing step, resulting in an irregular shape of the aluminum nitride particles. In contrast, aluminum nitride particles produced by reduction nitridation are generally round and have good packing properties.

[0074] [Other ingredients]

[0075] The thermally conductive silicone composition of the present invention may contain an organo(poly)siloxane such as methylpolysiloxane to adjust the elastic modulus and viscosity of the composition. Furthermore, to prevent degradation of the thermally conductive silicone composition, a conventionally known antioxidant such as 2,6-di-tert-butyl-4-methylphenol may be added as needed. Furthermore, thixotropy-imparting agents, dyes, pigments, flame retardants, anti-settling agents, and thixotropy-enhancing agents may be added as needed.

[0076] [Silicone composition]

[0077] The thermally conductive silicone composition of the present invention has a thermal conductivity of 1.3 W / mK or greater as measured by the transient plane heat source method. Details of the thermal conductivity measurement method are described in the following examples. While the upper limit is not particularly limited, the upper limit of the thermal conductivity measured by the transient plane heat source method can be, for example, 10 W / mK.

[0078] The thermally conductive silicone composition of the present invention has excellent compressibility. When pressurized at 4.1 MPa for 2 minutes, the thickness of the thermally conductive silicone composition is preferably within the range of 0.5 to 10 μm, more preferably within the range of 0.5 to 5 μm. The thickness during pressurization can be measured, for example, by the method described in the following Examples.

[0079] The heat conductive silicone composition of the present application can achieve both high thermal conductivity and good compressibility, and thus has low thermal resistance. The thermal resistance of the heat conductive silicone composition measured by the laser flash method at 25°C is preferably 5.0 mm 2 or less, further preferably 3.0 mm 2 or less. The lower limit is not particularly limited, but in view of physical factors, for example, it can be set to 0.1 mm 2 or less. In addition, the details of the measurement method of thermal resistance are, for example, the method of the following Example.

[0080] The absolute viscosity of the heat conductive silicone composition of the present application measured at 25°C is preferably 3 to 500 Pa-s, more preferably 10 to 500 Pa-s. If the absolute viscosity is 3 Pa-s or more, the shape is easily maintained, and the operability becomes good. On the other hand, if the absolute viscosity is 500 Pa-s or less, it becomes easy to eject, and thus the operability becomes good. The absolute viscosity can be adjusted by blending the above-described components. In the present application, the absolute viscosity is, for example, the value measured at 25°C at a shear rate of 6 S -1 .

[0081] [Semiconductor device]

[0082] The semiconductor device of the present application has the heat conductive silicone composition of the present application present in a gap of 10 μm or less in thickness formed between a heat generating body such as an IGBT and a cooling body. The heat conductive silicone composition of the present application can be compressed to 10 μm or less in thickness. Thus, compared to conventional heat conductive silicone compositions, it is expected that the cooling efficiency will be improved. The lower limit of the gap formed between the heat generating body and the cooling body is not particularly limited, and for example, it can be set to 0.2 μm. Although Figure 1 a representative structure is shown, the present application is not limited to this structure. Figure 1 The semiconductor device shown has the heat conductive silicone composition 2 present in the gap between the IGBT 1 as the heat generating body and the cooling fin 3 as the cooling body. The heat generated by the IGBT 1 is transmitted to the cooling fin 3 via the heat conductive silicone composition 2, and is dissipated to the cooling water 4 in contact with the cooling fin 3.

[0083] The manufacturing method of the semiconductor device of the present application is not particularly limited, but since the thickness of the heat conductive silicone composition is set to 10 μm or less, it is preferable to assemble it at a pressure of 0.1 MPa or more, and further preferable to assemble it at a pressure of 4.0 MPa or more. By increasing the pressure at the time of compression of the heat conductive silicone composition, the time taken for compression can be reduced.

[0084] Method for producing thermally conductive silicone composition

[0085] A method for producing the thermally conductive silicone composition of the present application will be described, but is not limited thereto.

[0086] The method for producing the thermally conductive silicone composition of the present application is not particularly limited as long as it is a method for producing a conventional thermally conductive silicone composition. For example, a method including a step of mixing the above-mentioned (A) component and (B) component can be exemplified, and specifically, it can be obtained by mixing the above-mentioned (A) component and (B) component, and other arbitrary components. As a mixing device, there is no particular limitation, and a mixer such as Trimix, Twinmix, Planetary Mixer (all are registered trademarks of mixers manufactured by INOUE MFG., INC.), Ultra Mixer (registered trademark of a mixer manufactured by MIZUHO INDUSTRIAL CO., LTD.), HIVIS DISPER MIX (registered trademark of a mixer manufactured by Tokushu Kika Kogyo Co., Ltd.) can be used. Furthermore, a three-roll finishing treatment or the like can be performed to break the agglomeration of the (B) aluminum nitride particles as a thermally conductive filler.

[0087] In the step of mixing the above-mentioned (A) component and (B) component, by mixing at a temperature of 100°C or higher for 30 minutes or more, the (A) component can be sufficiently surface-treated to the (B) component, thereby suppressing deterioration of thermal resistance with time. The upper limit of the temperature in this mixing step is not particularly limited, and is preferably 200°C or lower. Furthermore, the upper limit of the time in this mixing step is not particularly limited, and can be set to 4 hours, for example.

[0088] Examples

[0089] Hereinafter, the present application will be specifically described by Examples and Comparative Examples, but the present application is not limited to the following Examples.

[0090] The components used are as described below.

[0091] [(A) component]

[0092] (A-1) monoterminally trimethoxysilyl group-containing dimethylpolysiloxane represented by the following formula

[0093] [Chemical Formula 3]

[0094]

[0095] (A-2) dimethylpolysiloxane not having a hydrolyzable functional group represented by the following formula (comparative product)

[0096] [Chemical Formula 4]

[0097]

[0098] [(B) component]

[0099] (B-1) Aluminum nitride particles having an average particle diameter of 1.0 μm and 0.1 vol% or less of coarse powder of 10 μm or more

[0100] (B-2) Aluminum nitride particles having an average particle diameter of 1.4 μm and 0.4 vol% or less of coarse powder of 10 μm or more

[0101] (B-3) Aluminum nitride particles having an average particle diameter of 0.7 μm and 0.1 vol% or less of coarse powder of 10 μm or more

[0102] (B-4) Aluminum nitride particles (comparative product) having an average particle diameter of 1.5 μm and 5.0 vol% or less of coarse powder of 10 μm or more

[0103] [Examples 1 to 5, Comparative Examples 1 to 4]

[0104] [Preparation of thermally conductive silicone composition]

[0105] A thermally conductive silicone composition was prepared by blending the above (A) component and (B) component in the blending amounts shown in Tables 1 and 2 below, and in the following manner.

[0106] The (A) component and (B) component were added to a 5 liter Planetary Mixer (manufactured by INOUE MFG., INC.) and mixed at 170°C for 1 hour. After cooling to room temperature, mixing was performed until uniform, thereby preparing a thermally conductive silicone composition.

[0107] The viscosity, thermal conductivity, compressibility and thermal resistance of each thermally conductive composition obtained by the above method were measured in the following manner. The results are shown in Tables 1 and 2.

[0108] [Viscosity]

[0109] The absolute viscosity of the thermally conductive silicone composition was measured using a helical viscometer manufactured by Malcom Co., Ltd. under the conditions of 25°C and 6 S of rotation number. -1

[0110] [Thermal conductivity]

[0111] ​The thermally conductive silicone composition was wrapped with kitchen wrap and placed in a drawstring bag to obtain a test piece. The thermal conductivity of the test piece was measured at 25° C. using TPA-501 manufactured by KYOTO ELECTRONICS MANUFACTURING CO., LTD.

[0112] [Compressibility]

[0113] The prepared thermally conductive silicone composition was sandwiched between silicon wafers cut into circular pieces with a diameter of 1 mm, and pressurized at 4.1 MPa for 2 minutes using AUTOGRAPH AG-5KN ZPLUS manufactured by Shimadzu Corporation, and then the thickness was measured.

[0114] [Thermal resistance]

[0115] The above test piece was used to measure the thermal resistance at 25° C. using a thermal resistance measuring instrument based on a laser flash method (Xenon Flash Analyzer; LFA447 NanoFlash manufactured by NETZSCH Japan KK).

[0116] [Thermal resistance after thermal cycling]

[0117] The test pieces were subjected to a thermal shock test using a thermal shock tester TSE-11A manufactured by ESPEC CORP., with 1000 cycles of -40°C x 30 minutes → 150°C x 30 minutes as one cycle. The thermal resistance was then measured at 25°C.

[0118] [Table 1]

[0119]

[0120] [Table 2]

[0121]

[0122] According to the results in Tables 1 and 2, Examples 1 to 5, which satisfy the requirements of the present invention, provide thermally conductive silicone compositions having high thermal conductivity and good compressibility to be compressed to 10 μm or less.

[0123] On the other hand, Comparative Example 1, which did not use component (A) of the present invention, failed to produce a uniform thermally conductive silicone composition. Furthermore, Comparative Example 2, in which the thermally conductive filler content exceeded 70% by volume, also failed to produce a uniform thermally conductive silicone composition. Furthermore, Comparative Example 3, in which the thermally conductive filler content was less than 50% by volume, exhibited a significant decrease in thermal conductivity. Comparative Example 4, in which aluminum nitride particles with a coarse powder content of 10 μm or greater exceeding 1.0% by volume of the total thermally conductive filler were used as a thermally conductive filler, exhibited significantly poor compressibility.

[0124] In addition, the present application is not limited to the above-described embodiments. The above-described embodiments are examples, and technical solutions having substantially the same configuration as the inventive concept described in the claims of the present application and exerting the same effects are included in the technical scope of the present application.

Claims

1. A thermally conductive silicone composition, characterized in that: Contains the following components (A) and (B): (A) a hydrolyzable organopolysiloxane having an alkoxysilyl group; 50 to 70% by volume of (B) aluminum nitride particles having an average particle size of 0.5 μm to 2.0 μm, wherein the content of coarse powder having a particle size of 10 μm or greater in the particles as determined by laser diffraction particle size distribution measurement is 0.1% by volume or less of the total aluminum nitride particles; The thermal conductivity of the thermally conductive silicone composition measured by a transient plane heat source method is greater than 1.3 W / mK.

2. The thermally conductive silicone composition according to claim 1, wherein The aluminum nitride particles have an oxygen content of 1.0 mass % or less.

3. The thermally conductive silicone composition according to claim 1, wherein The thermal resistance measured by the laser flash method at 25°C is 5.0 mm 2 ·K / W or less 4. The thermally conductive silicone composition according to claim 2, wherein The thermal resistance measured by the laser flash method at 25°C is 5.0 mm 2 ·K / W or less 5. The thermally conductive silicone composition according to any one of claims 1 to 4, wherein: The shear rate measured by a spiral viscometer at 25°C is 6S -1 The absolute viscosity is 3 to 500 Pa·S.

6. A semiconductor device, characterized in that: The thermally conductive silicone composition according to any one of claims 1 to 5 is present in a gap having a thickness of 10 μm or less formed between a heating element and a cooling element.

7. The semiconductor device according to claim 6, wherein: The heating element is an insulated gate bipolar transistor.

8. A method for preparing the thermally conductive organosilicon composition according to any one of claims 1 to 5, characterized in that: The method comprises mixing the components (A) and (B) at a temperature of 100° C. or higher for 30 minutes or longer.

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