JP2006005239A - Heat exchange insulating member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive heat exchange insulating member which electrically insulates two members having a temperature gradient therebetween and efficiently transfers heat from a high temperature portion to a low temperature portion. <P>SOLUTION: The heat exchange insulating member comprises a high temperature portion 4, a low temperature portion 2 in which a temperature is lower than that of the high temperature portion 4, and an amorphous carbon-silicon member 3 which is arranged on at least a portion of a border between the high temperature portion 4 and the low temperature portion 2 and includes C and Si. The amorphous carbon/silicon member 3 electrically insulates the high temperature portion 4 from the low temperature portion 2 and carries out a heat exchange between the high temperature portion 4 and the low temperature portion 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchange insulating member that electrically insulates a plurality of members having temperature differences and efficiently performs heat transfer between the members.

For example, Patent Document 1 describes a resin material having high electrical insulation. Patent Document 2 describes an aluminum (Al) alloy having high electrical insulation. The Al surface is anodized. Patent Document 3 describes an amorphous carbon film containing hydrogen (H) and silicon (Si).
JP 2000-195337 A JP 2000-349320 A Japanese Patent Laid-Open No. 05-39731

  However, for example, the heat dissipation of a resin material as described in Patent Document 1 is low. Patent Document 2 does not disclose the heat dissipation of the Al alloy. Incidentally, Patent Document 3 describes amorphous carbon having high wear resistance and high seizure resistance. However, Patent Document 3 does not disclose anything regarding electrical insulation and heat dissipation. In contrast, ceramics have both high electrical insulation and high heat dissipation. However, ceramic is very expensive.

  Accordingly, an object of the present invention is to provide a heat exchange insulating member that is inexpensive and has high electrical insulation and high heat dissipation.

  The heat exchange insulating member of the present invention has been made to overcome the above-described problems, and is provided on at least a part of the high temperature part, the low temperature part lower than the high temperature part, and the boundary between the high temperature part and the low temperature part. And an amorphous carbon-silicon member including carbon (C) and Si, wherein the amorphous carbon-silicon member electrically insulates the high temperature portion and the low temperature portion, and the high temperature portion and the low temperature portion. It is characterized by exchanging heat with the part.

  That is, the amorphous carbon-silicon member which comprises this invention is provided with high electrical insulation and high heat dissipation by containing C and Si.

  According to the heat exchange insulating member of the present invention, it is inexpensive and can electrically insulate two members having a temperature difference and efficiently dissipate heat from the high temperature portion to the low temperature portion.

  The heat exchange insulating member of the present invention is incorporated in various electronic devices, electrical appliances, vehicles, and the like.

(Inverter cooling device and semiconductor module)
Hereinafter, an embodiment in which the heat exchange insulating member of the present invention is embodied as an inverter cooling device and a semiconductor module in EHV (Electric and Hybrid Vehicle) will be described.

  FIG. 1 is a cross-sectional view of an inverter cooling device and a semiconductor module in EHV. FIG. 2 is an enlarged view of A in FIG. The high temperature part of the heat exchange insulating member of the present invention corresponds to the semiconductor module 4. The low temperature part of the heat exchange insulating member corresponds to the cooling plate 2. The amorphous carbon-silicon member is a coating 3 formed on the entire surface of the main body 1 of the cooling device. Hereinafter, the cooling device of FIG. 1 will be described.

  The semiconductor module 4 is disposed so as to be sandwiched between the two cooling plates 2. The LLC (Long Life Coolant) circulates in the main body 1 of the cooling device. LLC also flows inside the cooling plate 2 in the direction of the arrow. Heat from the semiconductor module 4 is transmitted to the cooling plate 2 through the coating 3. Further, the heat is transferred from the cooling plate 2 to the LLC and transferred to the heat radiating portion 5. In the heat radiating part 5, the heat of LLC is radiated. Then, the radiated LLC is circulated through the main body 1 of the cooling device again.

  The semiconductor module 4 is cooled by repeating the above steps. That is, heat exchange is performed between the semiconductor module 4 and the cooling plate 2 through the coating 3.

(Amorphous carbon-silicon member)
Hereinafter, various embodiments of the amorphous carbon-silicon member which is a component of the heat exchange insulating member of the present invention will be described.

  The amorphous carbon-silicon member of the present invention contains C and Si. From the viewpoint of electrical insulation, the preferred Si / C mass% ratio is 0.43 or more. In addition, the Si / C mass% ratio of 0.43 or more was clarified by experiments to be described later. However, when the Si / C mass% ratio is 0.43 or more, the electrical insulation becomes high. Because.

  Moreover, it is preferable that the amorphous carbon-silicon member contains H from a viewpoint of electrical insulation. Furthermore, the more preferable content rate of H is 20 at% or more. This is because if the H content is less than 20 at%, many graphite components having low electrical insulation are formed on the surface of the amorphous carbon-silicon member.

From the viewpoint of electrical insulation, the preferable density of the amorphous carbon-silicon member is 2.0 g / cm ³ or more.

  By the way, the form of the amorphous carbon-silicon member may be a thin plate sandwiched between the high temperature part and the low temperature part, or may be a film formed on at least one of the surface of the high temperature part and the surface of the low temperature part. The amorphous carbon-silicon member has high electrical insulation and high heat dissipation even in the form of a film (hereinafter referred to as “amorphous carbon-silicon film” as appropriate).

  Hereinafter, an embodiment as an amorphous carbon-silicon film will be described. From the viewpoint of electrical insulation, the preferred amorphous carbon-silicon film thickness is 7.6 μm or more. A more preferable film thickness is 10 μm or more.

  PVD (physical vacuum deposition) using ion plating, sputtering, ion beam, and CVD (chemical vacuum deposition) using heat, light, plasma, etc. Law.

  By using the CVD method, a thicker amorphous carbon-silicon film can be formed. Further, by using the CVD method, a film can be uniformly formed even on a base material having a complicated shape. Therefore, it is preferable to use the CVD method as a method for forming the amorphous carbon-silicon film.

Hereinafter, the formation process of the amorphous carbon-silicon film by the CVD method using plasma will be described. First, a base material is placed in a sealed container, and the inside of the container is evacuated to 0.001 Pa or less, for example. Next, a temperature raising gas such as hydrogen (H ₂ ) is introduced. Then, the base material is heated by generating plasma energy. Then, a film forming gas is introduced into the sealed container. Therefore, a film is formed on the surface of the base material by discharging the film forming gas. Here, the film-forming gas is composed of a raw material mixed gas and an atmospheric gas. A carbon compound gas and a silicon compound gas can be used as the raw material mixed gas. As the carbon compound gas, methane (CH ₄ ), other hydrocarbon gas (CmHn), or the like can be used. Further, tetramethylsilane (Si (CH ₃ ) ₄ ), silane (SiH ₄ ), silicon tetrachloride (SiCl ₄ ), or the like can be used as the silicon compound gas. As the atmospheric gas, H ₂ , argon (Ar), or the like can be used.

(High temperature part, low temperature part)
Hereinafter, various embodiments of the high-temperature part and the low-temperature part which are components of the heat exchange insulating member of the present invention will be described.

  The high-temperature part and the low-temperature part, which are constituent elements of the present invention, do not have other elements to be limited as long as the temperature of the high-temperature part is higher than the temperature of the low-temperature part. For example, the high temperature part and the low temperature part may be in any state of gas, liquid, and solid. Furthermore, the low temperature part is not limited to the cooling pipe, but may be air blown by a fan or the like.

  When the amorphous carbon-silicon member is limited as a film, at least one of the high temperature portion and the low temperature portion is a base material. As the base material, for example, cemented carbide, iron-based metal, Al alloy, titanium (Ti) alloy, ceramic, or the like can be used. Here, adhesion between Al and Si which is a component of the amorphous carbon-silicon film is high. Accordingly, Al or an Al alloy is preferable as the base material of the amorphous carbon-silicon film.

  In addition, according to an application environment, the shape of a high temperature part, a low temperature part, an amorphous carbon-silicon member, a state, etc. can be changed or improved suitably. Therefore, the versatility of the present invention is very high.

  Hereinafter, the present invention will be described in detail by way of examples. However, the following examples do not limit the present invention. Various modifications and improvements that can be made by those skilled in the art can also be implemented.

  The experiment of the electrical characteristics and thermal characteristics of the amorphous carbon-silicon member in the heat exchange insulating member of the present invention will be described. In this experiment, the heater in the measuring device in the thermal resistance measurement test is used as the high temperature part. The low temperature part is an Al (JIS standard: A3003) plate. The amorphous carbon-silicon film is formed on the surface of the Al plate.

(Formation process of Example)
Hereinafter, a sample forming process using the plasma CVD method will be described. In addition, 16 samples of Examples were prepared. Examples 1 to 16 shown in Table 1 correspond to amorphous carbon-silicon films of 16 samples each.

As a method for forming an amorphous carbon-silicon film, first, an Al plate serving as a sample base material was placed in a sealed container. And evacuation was performed to 0.001 Pa or less. Next, the Al plate was heated using a heater and plasma energy. Then, a mixed gas of H ₂ and Ar was glow-discharged to clean the surface of the Al plate by ion bombardment. The purpose of this cleaning is to remove dirt on the surface of the Al plate and form a uniform film on the surface of the Al plate. Thereby, formation of pinholes in the film can be prevented. Further, a film forming gas was introduced into the sealed container to cause glow discharge. Thereby, an amorphous carbon-silicon film was formed on the surface of the Al plate. Here, the film-forming gas is composed of a raw material mixed gas and an atmospheric gas. In this experiment, a gas composed of CH ₄ and Si (CH ₃ ) ₄ was used as a raw material mixed gas. A mixed gas composed of H ₂ and Ar was used as the atmospheric gas. After formation, the vacuum vessel and the sample were cooled to a temperature that could be taken out into the atmosphere. Finally, the sample was taken out from the vacuum container.

The difference in the process of forming 16 samples is the component ratio of the raw material mixed gas and the film formation time. By controlling the component ratio of the raw material mixed gas, the Si / C mass% ratio of the amorphous carbon-silicon film can be adjusted. For example, the Si / C mass% ratio can be increased by increasing the proportion of the Si (CH ₃ ) ₄ component in the raw material mixed gas. Further, the film thickness of the amorphous carbon-silicon film can be adjusted by controlling the film formation time. For example, the film thickness of the amorphous carbon-silicon film can be increased by increasing the film formation time. That is, the difference in the Si / C mass% ratio of the amorphous carbon-silicon film in each sample is due to the difference in the component ratio of the raw material mixed gas. Moreover, the difference in the film thickness of the amorphous carbon-silicon film in each sample is due to the difference in the film formation time.

  Therefore, 16 different samples were prepared by controlling the component ratio of the raw material mixed gas and the film formation time. In addition, Si / C mass% ratio of Examples 1-16 was measured using EPMA (manufacturer: Shimadzu Corporation, model: EPMA1600).

(Comparative example)
Hereinafter, Comparative Examples 1 to 3 will be described. Comparative Example 1 is a silicon nitride ceramic plate. Comparative Example 2 is a polypropylene resin insulating sheet. Comparative Example 3 is a film made of amorphous carbon. The base material of this film is a surface of Cu plated with nickel-phosphorus (Ni-P). Moreover, PVD method by sputtering was used as a method for forming the film.

  The experimental results of Comparative Examples 1 to 3 and Examples 1 to 16 are shown in Table 1.

（特性評価方法）
以下、測定装置について簡単に記載する。比較例１〜３および実施例１〜１３の膜厚は渦電流式膜厚計〈メーカ：ケット科学研究所、型式：ＬＨ−３００Ｊ〉を用いて測定した。実施例１４〜１６の膜厚は段差計〈メーカ：東京精密、型式：ＳＵＲＦＣＯＭ ３０００Ａ〉を用いて測定した。絶縁耐圧は短時間絶縁破壊試験機〈メーカ：日化テクノサービス、型式：ＨＡＴ−３００−１００ＲＨＯ形〉を用いて測定した。短時間絶縁破壊試験にともなう昇圧速度は１２２Ｖ／ｓｅｃであった。なお、絶縁耐圧が高いほど、電気絶縁性は高い。絶縁耐圧の測定は比較例１〜３および実施例１〜９に対して行った。熱抵抗は熱抵抗測定試験より求めた。なお、熱抵抗の測定は、比較例１〜３および実施例１０〜１３に対して行った。

(Characteristic evaluation method)
Hereinafter, the measuring apparatus will be briefly described. The film thicknesses of Comparative Examples 1 to 3 and Examples 1 to 13 were measured using an eddy current film thickness meter (maker: Kett Science Laboratory, model: LH-300J). The film thicknesses of Examples 14 to 16 were measured using a step gauge (manufacturer: Tokyo Seimitsu, model: SURFCOM 3000A). The withstand voltage was measured using a short-time dielectric breakdown tester (manufacturer: Nikka Techno Service, model: HAT-300-100RHO type). The pressure increase rate associated with the short-time dielectric breakdown test was 122 V / sec. Note that the higher the withstand voltage, the higher the electrical insulation. The insulation withstand voltage was measured for Comparative Examples 1 to 3 and Examples 1 to 9. The thermal resistance was obtained from a thermal resistance measurement test. In addition, the measurement of thermal resistance was performed with respect to Comparative Examples 1-3 and Examples 10-13.

  The H content was measured using RBS (Rutherford Backscattering Analysis) and HFS (Hydrogen Forward Scattering Analysis) <Manufacturer: Nissin High Voltage, Model: AN-2500>. By using RBS and HFS in combination, the composition of a substance containing H can be accurately measured. In addition, the measurement of the content rate of H was performed with respect to the comparative example 3 and Examples 14-16.

  The density was derived using the formula: mass change before and after film formation / (film thickness x formation area). In addition, the density of the comparative example 3 and the density of Examples 1-13 were calculated | required.

(Experimental result)
Hereinafter, the result of the film | membrane characteristic of Examples 1-16 obtained by said measuring apparatus is demonstrated.

  With respect to Examples 1, 4, 6, and 9, the withstand voltage obtained by the short-time dielectric breakdown tester is shown in FIGS. In addition, all the film thicknesses of Examples 1, 4, 6, and 9 are 20 μm. FIG. 3 shows that the withstand voltage increases as the Si / C mass% ratio increases. That is, the higher the Si / C mass% ratio, the higher the electrical insulation. Hereinafter, Example 1 and Example 4 are compared. The Si / C mass% ratio of Example 1 is 0.25, and the Si / C mass% ratio of Example 4 is 0.43. The withstand voltage of Example 1 is 1.0 kV, and the withstand voltage of Example 4 is 1.8 kV. It can be seen that the withstand voltage of Example 4 is much higher than that of Example 1. Therefore, it can be said that the Si / C mass% ratio preferable from the viewpoint of electrical insulation is 0.43 or more.

Furthermore, it can be seen from FIG. 4 that the withstand voltage increases as the density increases. Hereinafter, Example 1 and Example 4 are compared. The density of Example 1 is 1.9 g / cm ³ and the density of Example 4 is 2.0 g / cm ³ . The withstand voltage of Example 1 is 1.0 kV, and the withstand voltage of Example 4 is 1.8 kV. It can be seen that the withstand voltage of Example 4 is much higher than that of Example 1. Therefore, it can be said that a preferable density from the viewpoint of electrical insulation is 2.0 g / cm ³ or more.

  With respect to Examples 2 to 5 and 7 to 9, the withstand voltage obtained by the short time dielectric breakdown tester is shown in FIG. In addition, Si / C mass% ratio of Examples 2-5 is 0.43. The Si / C mass% ratio of Examples 7 to 9 is 1.0. If the Si / C mass% ratio is constant, the withstand voltage increases as the film thickness increases. This can be seen from FIG. Hereinafter, Example 7 and Example 8 are compared. The film thickness of Example 7 is 5.3 μm, and the film thickness of Example 8 is 7.6 μm. The withstand voltage of Example 7 is 1.0 kV, and the withstand voltage of Example 8 is 1.5 kV. It can be seen that the withstand voltage of Example 8 is much higher than that of Example 7. Therefore, it can be said that a preferable film thickness is 7.6 μm or more from the viewpoint of electrical insulation.

  From FIG. 5, Example 2 and Example 3 are compared. The film thickness of Example 2 is 3 μm, and the film thickness of Example 3 is 10 μm. The withstand voltage of Example 2 is 1.0 kV, and the withstand voltage of Example 3 is 1.7 kV. It can be seen that the withstand voltage of Example 3 is much higher than that of Example 2. Therefore, it can be said that a more preferable film thickness is 10 μm or more from the viewpoint of electrical insulation.

  The thermal resistance calculated | required by the thermal resistance measurement test regarding Examples 10-13 is shown in FIG. FIG. 6 shows that the thermal resistance increases as the film thickness increases. In addition, any thermal resistance of Examples 10-13 was low. That is, all the heat dissipation of Examples 10-13 was high.

  By the way, Examples 14 to 16 contain 28 to 32 at% of H. From the viewpoint of electrical insulation, a more preferable H content is 20 at% or more. All of Examples 14 to 16 contained 20 at% or more of H.

(Comparison between Examples and Comparative Examples)
Hereinafter, based on an experimental result, an Example and Comparative Examples 1-3 are compared and considered.

  First, the amorphous carbon-silicon film of the example and the silicon nitride ceramic plate of Comparative Example 1 are compared. From the viewpoints of electrical insulation and heat dissipation, the amorphous carbon-silicon coating does not reach the silicon nitride ceramic plate. However, the amorphous carbon-silicon coating can be formed on the base material at low cost. The cost for forming the amorphous carbon-silicon film is 1/10 to 1/5 of the cost for the silicon nitride ceramic plate of Comparative Example 1.

  Next, the amorphous carbon-silicon film of the example and the polypropylene resin insulating sheet of Comparative Example 2 are compared. The withstand voltage of the amorphous carbon-silicon film is lower than that of the polypropylene resin insulating sheet. However, the thermal resistance of the amorphous carbon-silicon film is much lower than that of the polypropylene resin insulating sheet. In other words, the heat dissipation of the amorphous carbon-silicon film is much higher than that of the polypropylene resin insulating sheet.

  Furthermore, the amorphous carbon-silicon film of the example and the amorphous carbon film of Comparative Example 3 are compared. From Table 1, the withstand voltage of the amorphous carbon-silicon film is higher than the withstand voltage of the amorphous carbon film. However, when the film thickness of the amorphous carbon-silicon film and the film thickness of the amorphous carbon film are the same, the withstand voltage of the amorphous carbon-silicon film is much higher than the withstand voltage of the amorphous carbon film. This can be seen from Table 1 by comparing Example 3 (film thickness: 10 μm, withstand voltage: 1.7 kV) with Comparative Example 3 (film thickness: 10 μm, withstand voltage: 1.0 kV). The thermal resistance of the amorphous carbon-silicon film is lower than that of the amorphous carbon film. That is, the heat dissipation of the amorphous carbon-silicon film is higher than that of the amorphous carbon film. Thus, when the film thickness of the amorphous carbon-silicon film and the film thickness of the amorphous carbon film are the same, the electric insulation and heat dissipation of the amorphous carbon-silicon film are the same as the electric insulation and heat dissipation of the amorphous carbon film. Much higher.

It is sectional drawing of an inverter cooling device and a semiconductor module in EHV. It is an enlarged view of A in FIG. It is a graph which shows the relationship between Si / C mass% ratio and electrical insulation regarding Example 1, 4, 6, 9. FIG. It is a graph which shows the relationship between a density and electrical insulation regarding Examples 1, 4, 6, and 9. It is a graph which shows the relationship between the film thickness of Examples 2-5 and Examples 7-9 and electrical insulation. It is a graph which shows the relationship between the film thickness of Examples 10-13, and electrical insulation.

Explanation of symbols

1: Body of cooling device 2: Cooling plate 3: Film 4: Semiconductor module 5: Heat radiation part

Claims (8)

  An amorphous carbon-silicon member including carbon (C) and silicon (Si) disposed at least at a part of a boundary between the high temperature part, a low temperature part lower than the high temperature part, and the high temperature part and the low temperature part; , And the amorphous carbon-silicon member electrically insulates the high temperature portion from the low temperature portion, and heat exchanges between the high temperature portion and the low temperature portion.   The heat exchange insulating member according to claim 1, wherein the amorphous carbon-silicon member further contains hydrogen (H), and the Si / C weight percent ratio of the amorphous carbon-silicon member is 0.43 or more.   The heat exchange insulating member according to claim 2, wherein the amorphous carbon-silicon member contains 20 at% or more of the H. The heat exchange insulating member according to claim 1, wherein the density of the amorphous carbon-silicon member is 2.0 g / cm ³ or more.   The amorphous carbon-silicon member is an amorphous carbon-silicon film formed on at least one of the surface of the high temperature part or the surface of the low temperature part, and the thickness of the amorphous carbon-silicon film is 7.6 μm or more. The heat exchange insulating member according to claim 1.   The heat exchange insulating member according to claim 5, wherein the amorphous carbon-silicon film has a thickness of 10 μm or more.   The heat exchange insulating member according to claim 5, wherein the amorphous carbon-silicon film is formed by a plasma CVD method.   The heat exchange insulating member according to claim 1, wherein the high temperature part is a semiconductor module, and the low temperature part is a cooling pipe through which a refrigerant for cooling the semiconductor module flows.

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