Heat dissipation component

Abstract

The heat dissipation member is substantially in the shape of a rectangular flat plate, and has a composite part in which a metal is impregnated in silicon carbide having voids, and a metal part different from the composite part. Here, the ratio of the volume of the metal part to the overall volume of the heat dissipation member is 2.9% or more and 12% or less. Further, when the length of the diagonal of the heat dissipation member in the shape of a rectangular flat plate is L and the heat dissipation member is viewed from above with one main surface as the upper surface, 40% or more of the total volume of the metal part exists in a region D at a distance of L / 6 from any one of the four corners of the heat dissipation member. And there is a hole in the metal part penetrating the region D.

Description

Technical Field

[0001] The present invention relates to a heat dissipation member. More specifically, it relates to a heat dissipation member substantially in the shape of a rectangular flat plate. Background Art

[0002] In recent years, as a heat dissipation component for power modules used in electric vehicles and electric railways, a metal-silicon carbide composite has gradually been used in place of conventional copper.

[0003] The thermal conductivity of the metal-silicon carbide composite is lower than that of copper. However, its thermal expansion coefficient is 6 to 10 ppm / K, which is about half of 17 ppm / K of copper. Therefore, it is easy to suppress the generation of cracks in the solder layer portion that bonds the ceramic circuit board and the heat dissipation plate constituting the module, and there is a tendency to obtain high reliability.

[0004] As the metal of the metal-silicon carbide composite, aluminum is often used.

[0005] For example, as described in Patent Document 1, an aluminum-silicon carbide composite can be produced by the following steps: (1) mixing additives, etc. in silicon carbide powder, (2) forming a molded body by dry pressing method, extrusion method, injection method, etc., (3) calcining the molded body to produce a porous molded body (preform) mainly composed of silicon carbide, and (4) impregnating the preform with a metal containing aluminum by a pressure impregnation method such as non-pressure impregnation method, liquid forging method, die casting method, etc.

[0006] For the metal-silicon carbide composite, surface processing and polishing are often carried out before plating processing. It is used as a heat dissipation component for dissipating heat generated by electronic and electrical components. This heat dissipation component is further screwed to other heat dissipation components such as heat sinks or product frames, etc. to form a module. Therefore, sometimes a hole for screw fixation is formed in advance on the outer periphery or near the metal-silicon carbide composite.

[0007] As a method for forming the hole portion, various methods are known. For example, as described in Patent Documents 1 and 2, the following method is known: using a molded body in which a hole is formed at a predetermined position by a pin or the like during molding when producing the molded body, or a molded body in which a hole portion is provided by processing a predetermined position after producing the molded body, etc., impregnating the metal, and then mechanically processing the metal portion to form a hole portion.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Patent No. 3468358 Gazette

[0011] Patent Document 2: Japanese Patent No. 3662221 Gazette Summary of the Invention

[0012] Problems to be Solved by the Invention

[0013] As described above, metal-silicon carbide composites tend to have high reliability as heat dissipation components. However, with the market demand, the performance requirements for reliability are getting higher and higher.

[0014] For example, recently, it has been sought to suppress crack generation even under more severe thermal cycling conditions than in the prior art. However, in the prior art, there are the following problems: the thermal stress generated by the difference in thermal expansion coefficients between the metal part and the metal-silicon carbide composite during thermal cycling becomes large, and cracks are likely to occur.

[0015] That is, there is a need for a metal-silicon carbide composite or a heat dissipation component having higher crack resistance than the prior art and satisfying the recent stringent reliability requirements.

[0016] The present invention has been made in view of the above circumstances. An object of the present invention is to provide a heat dissipation member having higher crack resistance than the prior art and capable of satisfying stringent reliability requirements.

[0017] Means for Solving the Problems

[0018] As a result of intensive studies by the inventors of the present application, the invention provided below has been achieved, and the above problems have been solved.

[0019] According to the present invention, there is provided a heat dissipation member,

[0020] which is substantially in the shape of a rectangular flat plate,

[0021] the heat dissipation member includes a composite part in which a metal is impregnated in silicon carbide having voids, and a metal part different from the composite part,

[0022] the ratio of the volume of the metal part to the total volume of the heat dissipation member is 2.9% or more and 12% or less,

[0023] when the length of the diagonal of the heat dissipation member is L and the heat dissipation member is viewed from above with one main surface as the upper surface, 40% or more of the total volume of the metal part exists in a region D at a distance of L / 6 from any one of the four corners of the heat dissipation member,

[0024] the heat dissipation member has a hole passing through the metal part in the region D.

[0025] Effects of the Invention

[0026] According to the present invention, there is provided a heat dissipation member having higher crack resistance than the prior art and capable of satisfying stringent reliability requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Regarding the above and other objects, features, and advantages, they will become more apparent from the following specific embodiments and the accompanying drawings below.

[0028] Figure 1 is a schematic diagram for explaining the heat dissipation member of the first embodiment. Figure 1 (a) shows the case of looking down on the heat dissipation member with one main surface as the upper surface, Figure 1 (b) is Figure 1 the cross-sectional view taken along the line A - A' of (a).

[0029] Figure 2 is a schematic diagram for explaining the heat dissipation member of the first embodiment. Auxiliary lines and the like are added for illustration.

[0030] Figure 3 is Figure 1 the enlarged view of the part indicated by α in (a). Auxiliary lines and the like are added for illustration.

[0031] Figure 4 is Figure 1 the enlarged view of the part indicated by α in (a). Auxiliary lines and the like are added for illustration.

[0032] Figure 5 is a schematic diagram for explaining the heat dissipation member of the first embodiment. Auxiliary lines and the like are added for illustration.

[0033] Figure 6 is a schematic diagram for explaining the heat dissipation member of the first embodiment. Auxiliary lines and the like are added for illustration.

[0034] Figure 7 is a schematic diagram for explaining the heat dissipation member of the second embodiment. Figure 7 (a) shows the case of looking down on the heat dissipation member with one main surface as the upper surface, Figure 7 (b) is Figure 7 the cross-sectional view taken along the line B - B' of (a).

[0035] Figure 8 is a schematic diagram showing an enlarged part of the heat dissipation member of the second embodiment. Auxiliary lines and the like are added for illustration.

[0036] Figure 9 is a schematic diagram for explaining the heat dissipation member of the third embodiment. Figure 9 (a) shows the case of looking down on the heat dissipation member with one main surface as the upper surface, Figure 9 (b) is Figure 9 the cross-sectional view taken along the line C - C' of (a).

[0037] Figure 10 ​​​​​​​​​​is a schematic diagram for explaining the heat dissipation member of the fourth embodiment. It shows the case of looking down on the heat dissipation member with one main surface as the upper surface.

[0038] Figure 11 is a diagram for explaining the measurement positions for obtaining the volume of the heat dissipation member. Detailed Embodiment

[0039] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0040] In all the drawings, the same reference numerals are assigned to the same components, and the description is appropriately omitted.

[0041] To avoid complexity, (i) if there are multiple identical components in the same drawing, sometimes only one of them is labeled with a reference numeral, and not all are labeled; (ii) especially after Figure 2 sometimes for components identical to Figure 1 the same components are not labeled again.

[0042] All the drawings are for illustrative purposes only. The shapes, dimensional ratios, etc. of the components in the drawings do not necessarily correspond to the actual objects. In particular, Figures 2 to 6 for Figure 1 a partial enlarged view of (a), but for the sake of easy understanding of the description, etc., the relative sizes of each part do not necessarily match Figure 1 (a).

[0043] In this specification, the term "substantially" means a range including manufacturing tolerances, assembly deviations, etc., unless otherwise specifically stated.

[0044] <First Embodiment>

[0045] Figure 1 is a schematic diagram for explaining the heat dissipation member (heat dissipation member 1) of the first embodiment.

[0046] Figure 1 (a) shows the case of looking down on the heat dissipation member 1 with one main surface as the upper surface, Figure 1 (b) is Figure 1 the sectional view taken along the line A - A' of (a).

[0047] As Figure 1 shown in (a), the heat dissipation member 1 is substantially in the shape of a rectangular flat plate. That is, when looking down on the heat dissipation member 1 with one of its main surfaces as the upper surface, it is substantially in the shape of a rectangular flat plate.

[0048] The heat dissipation member 1 typically has metal parts 5 at its four corners.

[0049] ​Alternatively, a part of the metal part 5 can be continuously provided at the peripheral part of the heat dissipation member 1. Here, the so-called "peripheral part" means that when the length of the short side is set as L1 and the length of the long side is set as L2 when looking down at the heat dissipation member 1 with one main surface of the heat dissipation member 1 as the upper surface, it is within L2 / 10 from the short side in the inner direction of the heat dissipation member 1, or within L1 / 10 from the long side in the inner direction of the heat dissipation member 1.

[0050] On the other hand, the part other than the metal part 5 in the heat dissipation member 1 is usually composed of a composite part 2 (hereinafter, also simply referred to as the composite part 2) in which a metal is impregnated in silicon carbide having voids. And the ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1 is 2.9% or more and 12% or less.

[0051] Figure 2 It is an additional figure for explaining the heat dissipation member 1, and is a figure obtained by adding some auxiliary lines and characters to the heat dissipation member 1 in Figure 1 (a).

[0052] Figure 2 In, the length of the diagonal of the rectangular flat heat dissipation member 1 is L. In addition, when looking down at the heat dissipation member 1 with one main surface as the upper surface, the region at a distance of L / 6 from any one of the four vertices of the heat dissipation member 1 is marked as "region D".

[0053] Here, the heat dissipation member 1 has a hole 3 that penetrates the metal part 5 existing in the region D. The hole 3 usually only penetrates the metal part 5 and does not pass through the composite part 2. In addition, the hole 3 is usually provided in a manner that penetrates between the two main surfaces of the heat dissipation member 1, and is preferably provided substantially perpendicular to the main surface of the heat dissipation member 1. By inserting a fixing member such as a screw into the hole 3, the heat dissipation member 1 can be fixed to other components.

[0054] In addition, more than 40% of the total volume of the metal part 5 exists in the region D.

[0055] Supplementally, the so-called heat dissipation member 1 being "substantially rectangular" means that, for example, as Figure 1 shown, at least one of the four corners of the heat dissipation member 1 may not be a right-angled shape, but may be made into a shape with a slightly rounded arc (of course, the four corners can be right-angled shapes).

[0056] Here, when at least one of the four corners of the heat dissipation member 1 is a shape with a rounded arc, the "vertex" of the rectangle can be defined as shown in Figure 3 ( Figure 3 is a magnified view of the part indicated by α in Figure 1 (a)). That is, the point P where the straight lines of the short side and the long side intersect when looking down at the heat dissipation member 1 can be defined as the "vertex". In addition, as Figure 3The point P determined as shown is set as the starting or ending point when measuring Figure 2 the length "L".

[0057] Regarding the reason why the heat dissipation member 1 has higher crack resistance than the prior art and can meet strict reliability requirements, it can be explained as follows.

[0058] If the heat dissipation member 1 is roughly explained, the heat dissipation member 1 has the following characteristics:

[0059] (1) The ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1 is 2.9% or more and 12% or less.

[0060] (2) Most or all of the metal part 5 is present in the parts near the four corners of the heat dissipation member 1.

[0061] (3) The part of the metal part 5 in the parts near its four corners has through-holes (hole 3).

[0062] Here, the ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1 is "2.9% or more", and most or all of the metal part 5 is present in the parts near the four corners of the heat dissipation member 1. Thus, holes 3 with a (sufficiently large) size suitable for mounting to other components can be provided in the metal part 5. It is considered that the heat dissipation member 1 can be firmly mounted to other components in this way, which helps to improve reliability.

[0063] On the other hand, the coefficient of thermal expansion of the metal part 5 is different from that of the composite part 2, and the ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1 is "12% or less". Thus, the thermal stress generated by thermal cycling can be sufficiently reduced. It is considered that this is particularly effective in reducing cracks (especially reducing cracks near the interface between the composite part 2 and the metal part 5 existing in region D).

[0064] Moreover, it is considered that by having through-holes (hole 3) in the part of the metal part 5 that is "less likely to break" and "less likely to generate cracks" compared to the composite part 2, cracks around the through-holes, that is, around the part fastened by screws, are further reduced (it is considered that due to the ductility of the metal, even if a force from a screw or the like is applied to the hole 3 in the part of the metal part 5, crack generation can be suppressed).

[0065] In addition, compared to the composite part 2, the metal part 5 has a tendency to have a low elastic modulus. This is related to the following advantages: it is less likely to break when forming the hole 3, or it is less likely to break when mounting the heat dissipation member 1 to other components with screws or the like (the low elastic modulus is related to the easy absorption of impact).

[0066] This advantage means that it is easier to mount the heat dissipation member 1 to other components with screws or the like, which is preferable in terms of improving productivity and the like.

[0067] In addition, the reduction of cracks or the improvement of reliability described above is higher than the level achieved by the prior art.

[0068] For example, in the embodiment of Patent Document 2 described above, it is shown that repeating the thermal cycle of 30 minutes at -40°C and 30 minutes at 125°C 300 times did not find cracks or fractures, but in the heat dissipation member of the first embodiment (and the heat dissipation members of the second and third embodiments described later), even when repeating the more severe thermal cycle of 30 minutes at -40°C and 30 minutes at 150°C (25°C higher than the conditions of the embodiment of Patent Document 2) 300 times, cracks or fractures can still be suppressed.

[0069] From the viewpoint of further reducing cracks, the ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1 is preferably 3.0% or more and 11.8% or less, and more preferably 3.2% or more and 11.5% or less.

[0070] The thickness of the metal part 5 existing in the region D is preferably approximately equal to the thickness of the composite part 2. The metal part 5 around the hole 3 is thick enough compared to the composite part 2, so that sufficient toughness, better crack resistance, etc. can be obtained.

[0071] Here, the so-called "substantially equal thickness" means that (the thickness of the metal part 5 / the thickness of the composite part 2) is, for example, 0.8 or more and 1.2 or less, and preferably 0.9 or more and 1.1 or less.

[0072] In addition, the "thickness of the composite part 2" here can, for example, adopt the thickness obtained in the thickness measurement described below. Figure 11 Regarding the "thickness of the metal part 5", when the metal part 5 continuously exists from the upper surface to the lower surface of the heat dissipation member 1 as shown, it can be obtained by measuring the metal part 5 with a micrometer or a vernier caliper. Of course, the method for obtaining the thickness is not limited to this, and any method that can measure with a certain degree of accuracy can be adopted. Figure 1

[0073] In addition, in Figure 2

[0074] In the four regions D at the four corners, metal parts 5 with substantially the same volume (substantially the same area when viewed from above) are respectively present. From the viewpoints of the reliability of the heat dissipation member 1 as a whole and preventing excessive stress from being applied only to specific parts, it is preferable that metal parts 5 with substantially the same volume are respectively present in the four regions D.

[0074] More specifically, in the four regions D located at the four corners, when the volume of the metal part 5 in the region D containing the largest volume of the metal part 5 is denoted as Vmax and the volume of the metal part 5 in the region D containing the smallest volume of the metal part 5 is denoted as Vmin, the value of Vmax / Vmin is preferably greater than 1 and less than 1.2.

[0075] Let the volume of the metal portion 5 existing in the region D be V 金属 , let the volume of hole 3 be V 孔 When V 孔 / (V 金属 +V 孔 ) value is preferably 0.60 or less, more preferably 0.55 or less, and even more preferably 0.50 or less. 孔 / (V 金属 +V 孔 ), but in view of manufacturing adaptability, etc., it can be, for example, greater than 0.1, preferably greater than 0.3, and more preferably greater than 0.5.

[0076] For the sake of caution, the volume V of the hole 3 is 孔 , is the volume occupied by the hole 3 in the hole 3 between the two main surfaces. For example, when the hole 3 is cylindrical and is arranged approximately perpendicular to the main surface of the heat dissipation member 1, V can be calculated by calculating "the area of ​​the hole 3 when the heat dissipation member 1 is viewed from one main surface of the heat dissipation member 1 as the upper surface × the thickness of the heat dissipation member 1 near the hole 3". 孔 In other words, V 孔 It may be the volume of the portion “hollowed out” from the heat dissipation member 1 when the hole 3 is provided in the heat dissipation member 1 .

[0077] Figure 4 Is magnification Figure 1 (a) is a diagram of a portion indicated by α (an enlarged diagram of one of the four corners of the heat dissipation member 1). Figure 4 In the example, let the volume of the metal portion 5 existing in the region D be V 金属 , let the volume of hole 3 be V 孔 When V 孔 / (V 金属 +V 孔 ) is within the above numerical range.

[0078] The above means that the size of the hole 3 is relatively small (not too large) relative to the metal portion 5 existing in the region D. As a result, a sufficient amount of metal to withstand the stress caused by the thermal cycle (especially the stress applied around the hole 3) can exist in the region D. Therefore, it is possible to achieve a higher degree of crack reduction.

[0079] As other viewpoints, Figure 5As shown in the figure, when one main surface of the heat dissipation member 1 is the upper surface and the radius of the hole 3 when looking down at the heat dissipation member 1 is r, it is preferable that the composite part 2 does not exist in the area within a distance of 1.3r from the center of the hole 3. More preferably, the composite part 2 does not exist in the area within a distance of 1.5r from the center of the hole 3. In other words, it is preferable that only the hole 3 itself or the metal part 5 exists in the area within a distance of 1.3r from the center of the hole 3.

[0080] The above means that the size of the hole 3 is relatively small (not too large) with respect to the metal part 5 existing in the area D, and the hole 3 is not located at the "edge" of the metal part 5 existing in the area D, but is located "near the center" thereof. Thus, when fixing the heat dissipation member 1 with a screw, the entire part of the "head" of the screw is more likely to be accommodated in the area of the metal part 5, so that breakage during installation and the like are less likely to occur. In addition, it is also considered that the stress caused by the thermal cycle (especially the stress applied to the periphery of the hole 3) can be more evenly borne by the entire metal part 5 existing in the area D, and reduction of cracks and the like can be achieved to a higher degree.

[0081] Supplementally, when the shape of the hole 3 when looking down cannot be regarded as a substantially perfect circle, the geometric center of gravity of the hole 3 can be used as the "center of the hole 3", and the radius of a circle having the same area as the area of the hole 3 can be used as the "radius of the hole 3".

[0082] From another perspective, as Figure 6 shown, when one main surface of the heat dissipation member 1 is the upper surface and looking down at the heat dissipation member 1, it is preferable that the hole 3 does not exist in the area within a distance of L / 40 from the vertex P of the heat dissipation member 1 (L is the length of the diagonal of the heat dissipation member 1 as described above). More preferably, the hole 3 does not exist in the area within a distance of L / 35 from the vertex P.

[0083] The above means that the hole 3 is not located at the "immediate edge" of the heat dissipation member 1, but the hole 3 is provided at a position that is separated from the edge (vertex) to a certain extent. Thus, technical effects such as the following can be considered: it becomes easier to evenly bear the stress as a whole of the heat dissipation member 1, and excessive stress is not applied only around the hole 3. That is, it is considered to have the effect of further reducing cracks and the like.

[0084] As described above, the metal part 5 can also be continuously provided at the peripheral part of the heat dissipation member 1. In other words, the structure of the heat dissipation member 1 can also be such that when looking at the heat dissipation member 1 from the outer peripheral surface direction, a part of the metal part 5 is formed on a part or all of the outer peripheral surface.

[0085] Since the metal part 5 exists not only around the hole 3 or near the four corners of the heat dissipation member 1, but also on the outer peripheral surface of the heat dissipation member 1, it becomes easier to evenly bear the stress as a whole of the metal part 5. Thus, cracks and the like can be further reduced.

[0086] In the first embodiment, the holes 3 are provided only at the four corners of the heat dissipation member 1. However, considering the structure of other components to which the heat dissipation member 1 is to be mounted, the characteristics of various materials constituting the heat dissipation components, etc., the holes 3 may also be present in positions other than the four corners of the heat dissipation member 1. For example, additional holes 3 may be provided near the midpoints of the long sides of the heat dissipation member 1, etc.

[0087] In addition, in the first embodiment, one hole 3 is provided in one region D, but a plurality of holes 3 may also be provided in one region D.

[0088] As an example, the length and width of the heat dissipation member 1 are about 60×100 mm to 140×200 mm.

[0089] As an example, the thickness of the heat dissipation member 1 is 2 mm or more and 6 mm or less, preferably 3 mm or more and 5 mm or less.

[0090] As an example, the radius r of the hole 3 is 3 mm or more and 12 mm or less.

[0091] The materials and raw materials of the metal part 5 and the composite part 2 will be described.

[0092] The metal part 5 can be a metal having any one of aluminum, copper, magnesium, silver, etc. as the main component (50% by mass or more). By using such a metal as the raw material of the metal part 5, the heat dissipation member 1 can have a thermal conductivity, a coefficient of thermal expansion, etc. suitable for use as a heat dissipation component.

[0093] The metal part 5 is preferably a metal having aluminum or magnesium as the main component, and more preferably a metal having aluminum as the main component.

[0094] In addition to the metal as the above main component, the metal part 5 may also contain other elements. For example, the metal part 5 preferably has aluminum as the main component and contains 0.1% by mass or more and 1.5% by mass or less of magnesium and 0.1% by mass or more and 18% by mass or less of silicon. By alloying aluminum with silicon and magnesium, the melting point of the alloy is lowered, the viscosity of the molten metal at high temperatures is lowered, and there is an advantage that a dense composite can be easily obtained in high-temperature casting, etc.

[0095] The metal part 5 preferably contains, for example, inorganic fibers in addition to the metal. By the metal part 5 containing inorganic fibers, shrinkage cavities generated during the manufacture of the heat dissipation member 1 can be suppressed (for example, it is easy to make the maximum value of the size of the shrinkage cavity 1.0 mm 2 as follows). It should be noted that the manufacturing method of the heat dissipation member 1 is as described below.

[0096] In addition, by making the metal part 5 contain inorganic fibers, further strengthening of the hole 3 and the surrounding metal part 5 can be achieved.

[0097] Furthermore, by including inorganic fibers in the metal part 5, the difference in the coefficient of thermal expansion between the composite part 2 can be reduced, and the thermal stress under thermal cycling can be further reduced.

[0098] Examples of the raw materials for the inorganic fibers include metals, metal oxides, glass, carbon, etc. Among them, metal oxides are preferred, and alumina or silica fibers are particularly preferred.

[0099] In particular, when the metal that is the main component of the metal part 5 is aluminum, from the perspective of affinity with aluminum, it is preferred to include alumina fibers in the metal part 5. As the alumina fibers, due to the affinity with aluminum, crystalline alumina fibers with an alumina content of 70% or more are particularly preferred.

[0100] From the perspective of achieving the above effects well in terms of balance, and from the ease of processing of the holes 3, etc., the amount of the inorganic fibers is preferably 3% by volume or more and 30% by volume or less, more preferably 5% by volume or more and 28% by volume or less, relative to the entire metal part 5.

[0101] Typically, the composite part 2 is formed by impregnating a silicon carbide having voids (also referred to as a preform, etc.) with a metal.

[0102] The silicon carbide having voids can be obtained, for example, by preparing one or more kinds of silicon carbide particles with an average particle diameter of 1 μm or more and 300 μm or less, compressing and molding them, and then heating and calcining them. Here, the relative density of the silicon carbide (the molded body of the silicon carbide having voids before impregnating the metal) is preferably 55% or more and 75% or less, more preferably 57% or more and 73% or less, and even more preferably 60% or more and 70% or less.

[0103] By setting the relative density of the silicon carbide to 55% or more and 75% or less, it is easy to set the coefficient of thermal expansion of the heat dissipation member 1 to about 6 ppm / K or more and 10 ppm / K or less. With such a design, it is easy to further reduce the thermal stress generated during thermal cycling.

[0104] The relative density of the silicon carbide is defined as the volume ratio of the silicon carbide in the volume of the molded body of the silicon carbide having voids before impregnating the metal.

[0105] When manufacturing the molded body, in addition to silicon carbide, a binder can also be mixed. Typically, the proportion of the binder remaining in the molded body is 10% or less relative to the relative density of the silicon carbide.

[0106] The metal impregnated in the composite part 2 and the metal contained in the metal part 5 are preferably the same metal (when it is an alloy, it is the same alloy composition).

[0107] First, this is related to the manufacturing method described below. That is, when the metal is impregnated into the silicon carbide molded body to form the composite part 2 and the metal part 5 at the same time, the metal impregnated into the composite part 2 and the metal contained in the metal part 5 are the same metal. In short, by making the metal impregnated into the composite part 2 and the metal contained in the metal part 5 the same, there is an advantage of easy manufacturing.

[0108] Furthermore, since the metal impregnated in the composite portion 2 is the same as the metal contained in the metal portion 5 , it is easy to make the thermal expansion coefficients of the respective portions consistent, and it can be said that it is easy to further reduce the thermal stress.

[0109] (Method for Manufacturing Heat Dissipation Member 1)

[0110] The method for producing the heat dissipation member 1 will be described. Of course, the method for producing the heat dissipation member 1 is not limited to the method described below. The heat dissipation member 1 can be produced using various known techniques.

[0111] For example, the heat dissipation member 1 can be manufactured according to the following procedure.

[0112] (1) Step of forming a flat plate-shaped molded body (having voids) having a notch and containing silicon carbide

[0113] (2) Step of arranging inorganic fibers in the notch of the molded body

[0114] (3) Step of impregnating the molded body and inorganic fibers with metal to form the composite portion 2 and the metal portion 5

[0115] (4) Step of cutting the metal-impregnated molded body into the shape of the flat plate-shaped heat dissipation member 1

[0116] (The "notch" in (1) and (2) is intended to be a part (such as the four corners) corresponding to the metal part 5 of the finally obtained heat dissipation member 1 in the rectangular flat plate-shaped molded body.)

[0117] The above sequence is described in more detail.

[0118] In the above-mentioned process (1) of forming a flat-plate-shaped molded body (having voids) having a notch and containing silicon carbide, as a method for molding the raw material silicon carbide powder, known dry pressing methods, wet pressing methods, extrusion molding methods, injection molding methods, casting methods, sheet molding and subsequent punching methods, etc. can be used.

[0119] At this time, in order to present an abnormal strength without cracking when impregnated with metal, an inorganic or organic binder may be appropriately added. In order to easily obtain a high-strength molded body, silica sol is preferably used as the binder. In order to increase the relative density, it is preferred to add a binder having a solid content of 20 or less relative to the silicon carbide 100 in terms of volume ratio.

[0120] For example, when applying the wet pressing method, a porous concave and convex mold is prepared, and a slurry composed of silicon carbide powder, binder, water, etc. is filled in the concave mold, and then compression molding is performed with the convex mold. When applying the wet pressing method, as long as the shaping can be carried out in such a way that a notch portion is formed in the formed body so that Figure 1 as shown, the metal part 5 forms a part of the outer peripheral surface of the heat dissipation member 1.

[0121] The notch portion is preferably formed by using a mold box or the like having the shape of the desired notch portion during compression molding. In addition, the notch portion can also be formed by machining (cutting, cutting, etc.) a plate-shaped formed body.

[0122] Although the formed body produced as described above varies depending on the manufacturing conditions, it usually undergoes drying, heat degreasing treatment, and then calcination to obtain a formed body with a specified strength.

[0123] As the calcination conditions, it is preferably carried out at a temperature of 700 °C or higher in an inert atmosphere or in the atmosphere. However, in the case of the atmosphere, if calcination is carried out at a temperature of 1100 °C or higher, sometimes the silicon carbide is oxidized, resulting in a decrease in the thermal conductivity of the obtained composite. Therefore, it is also preferably calcined at a temperature below this.

[0124] As described above, the relative density of the formed body is preferably 55% or more and 75% or less. By setting the relative density of the formed body to 55% or more and 75% or less, it is easy to design the thermal expansion coefficient of the heat dissipation member 1 to be about 6 ppm / K or more and 10 ppm / K or less.

[0125] In order to make the relative density of the formed body 55% or more and 75% or less, it is preferable to mix silicon carbide powders with different particle sizes. In the case of silicon carbide, as an example, powders obtained by mixing powders with an average particle size of 100 μm and powders with an average particle size of 10 μm or finer, or powders obtained by mixing powders with an average particle size of 60 μm and powders with an average particle size of 10 μm or finer can be cited.

[0126] Here, the average particle size can be obtained in the following manner: The particle size is obtained for 1000 particles using a scanning electron microscope (for example, "JSM-T200 type" manufactured by JEOL Ltd.) and an image analysis device (for example, manufactured by AVIONICS Corporation of Japan), and the average value of the particle sizes is calculated.

[0127] In the process of arranging the inorganic fibers at the notch portion of the molded body in (2) above, it is preferable to arrange the inorganic fibers at the notch portion of the molded body, that is, at the portions where the metal parts 5 are provided at the four corners. Thereby, shrinkage cavities generated during metal impregnation can be suppressed. In addition, the coefficient of thermal expansion of the metal part 5 can be made to easily approach the coefficient of thermal expansion of the composite part 2, which helps to further reduce the stress caused by thermal cycling.

[0128] Examples of the inorganic fibers that can be used are as described above, so repeated descriptions are omitted here.

[0129] In the process of impregnating the molded body and the inorganic fibers with metal to form the composite part 2 and the metal part 5 in (3) above, in order to impregnate the metal into the molded body, the so-called liquid forging method or die casting method can be adopted.

[0130] In the case of the liquid forging method, the molded body is filled in a mold with a runner having the shape of the product, and then it is placed in a pressure die. Then, the molten metal is injected into the die, sealed with a punch, and pressurized. Further, the molten liquid is cooled and solidified into a block. After cooling, a substance (metal-silicon carbide composite) in which the molded body is impregnated with metal can be obtained.

[0131] It is also possible to obtain a plurality of metal-silicon carbide composites at one time by improving the shape of the mold with a runner.

[0132] The die casting method is a method in which the molded body is placed in a mold having a cavity with the shape of the product, the mold is closed, and then metal is injected at high speed to obtain the composite.

[0133] When impregnating the molded body and the inorganic fibers with the molten metal, in either method, it is preferable to heat the molded body and the inorganic fibers before impregnation. This is to prevent the molten metal from directly solidifying when it is not sufficiently impregnated into the molded body during the impregnation process.

[0134] For example, when impregnating a metal mainly composed of aluminum, although it varies depending on the composition of the aluminum alloy used, the size and shape of the molded body, etc., it is preferably preheated to 550 °C or higher.

[0135] In addition, the molten liquid temperature of the molten aluminum or its alloy to be impregnated is usually preferably 750 °C or higher. When the metal containing aluminum contains 0.1 mass% or more and 1.5 mass% or less of magnesium and 0.1 mass% or more and 18 mass% or less of silicon, the temperature condition is particularly preferably 900 °C or lower.

[0136] In the process of cutting the molded body impregnated with metal into the shape of the flat heat dissipation member 1 in (4) above, the composite part 2, the hole 3, the metal part 5, etc. are cut into a specified shape to form.

[0137] More specifically, the metal-impregnated formed body is cooled to room temperature and then cut with a wet band saw or the like, whereby the heat dissipation member 1 having a desired shape can be obtained.

[0138] The heat dissipation member 1 manufactured by the above manufacturing method has a metal portion 5 in a part thereof. Holes 3 can be provided in the metal portion 5.

[0139] <Second Embodiment>

[0140] Figure 7 It is a schematic view for explaining the heat dissipation member (heat dissipation member 1B) of the second embodiment.

[0141] Figure 7 (a) shows a case of looking down on the heat dissipation member 1B with one main surface as the upper surface. Figure 7 (b) is Figure 7 A sectional view taken along line B - B' of (a).

[0142] As Figure 7 (a) shows, the heat dissipation member 1 is substantially in the shape of a rectangular flat plate. That is, when looking down on the heat dissipation member 1 with one main surface of the heat dissipation member 1 as the upper surface, it is substantially in the shape of a rectangular flat plate.

[0143] In the heat dissipation member 1B, there are: a first metal portion 5A including at least a part of its peripheral portion, and a second metal portion 5B that does not contact its peripheral portion and the first metal portion 5A. Especially in this regard, the heat dissipation member 1B is different from the heat dissipation member 1 of the first embodiment (in the heat dissipation member 1 of the first embodiment, all the metal portions 5 are "continuous").

[0144] Here, the second metal portion 5B preferably exists, as Figure 8 shown, in a range from L / 55 to L / 5, more preferably from L / 50 to L / 8, from the nearest vertex in the heat dissipation member 1B (L is the length of the diagonal of the heat dissipation member 1B).

[0145] In addition, in the second metal portion 5B, holes (holes 3) penetrate. The holes 3 generally only penetrate the metal portion 5B and do not pass through the composite portion 2. In addition, the holes 3 are generally provided so as to penetrate between the two main surfaces of the heat dissipation member 1, and are preferably provided substantially perpendicular to the main surface of the heat dissipation member 1.

[0146] In the second embodiment, the metal portion is divided into the first metal portion 5A and the second metal portion 5B, and the second metal portion 5B is moderately separated from the vertex of the heat dissipation member 1B. Thus, the second embodiment has the following technical significance (an additional technical significance not possessed by the first embodiment): making it easy to design the ratio of the metal portion to the whole heat dissipation member 1B to be small, and enabling sufficient toughness around the holes 3, and so on.

[0147] In the second embodiment, it can be substantially the same as the first embodiment in the following aspects. Therefore, repeated descriptions are omitted.

[0148] · A metal part may also be continuously provided at the peripheral part of the heat dissipation member 1B Figure 7 (in (a) and Figure 7 (b), the first metal part 5A)

[0149] · The metal part in the heat dissipation member 1B Figure 7 (in (a) and Figure 7 (b), parts other than the first metal part 5A and the second metal part 5B) are generally composed of a composite part 2 (composite part 2) in which a metal is impregnated in silicon carbide having voids

[0150] · The ratio of the volume of the metal part (the first metal part 5A and the second metal part 5B) to the overall volume of the heat dissipation member 1B is 2.9% or more and 12% or less

[0151] · 40% or more of the total volume of the metal part (the first metal part 5A and the second metal part 5B) exists in a region D at a distance of L / 6 from any vertex of the four corners of the heat dissipation member 1B

[0152] Regarding the features not clarified above, the manufacturing method of the heat dissipation member 1B, etc., it can also be substantially the same as the first embodiment.

[0153] <Third Embodiment>

[0154] Figure 9 It is a schematic diagram for explaining the heat dissipation member (heat dissipation member 1C) of the third embodiment.

[0155] Figure 9 (a) shows the case when looking down on the heat dissipation member 1C with one main surface as the upper surface, Figure 9 (b) is Figure 9 the cross-sectional view of (a) taken along C - C'.

[0156] As Figure 9 (a) shows, the heat dissipation member 1C is substantially in the shape of a rectangular flat plate. That is, when looking down on the heat dissipation member 1C with one of its main surfaces as the upper surface, it is substantially in the shape of a rectangular flat plate.

[0157] There is a surface metal layer 4 on the main surface of the heat dissipation member 1C. In particular, in this regard, the heat dissipation member 1 is different from the heat dissipation member 1 of the first embodiment and the heat dissipation member 1B of the second embodiment.

[0158] Typically, the surface metal layer 4 can be made of the same metal as the metal constituting the metal part 5. That is, Figure 9In [the figure], the surface metal layer 4 and the metal part 5 are shown with different hatching, but when the surface metal layer 4 and the metal part 5 are made of the same metal, there is no "boundary" between the surface metal layer 4 and the metal part 5.

[0159] Supplementary to this, when the heat dissipation member 1C has the surface metal layer 4 as in the third embodiment, the volume of the surface metal layer 4 is also included in the volume of the metal part 5.

[0160] That is, in the third embodiment, the total volume of the surface metal layer 4 and the metal part 5 is 2.9% or more and 12% or less with respect to the whole of the heat dissipation member 1C. In addition, 40% or more of the total volume of the surface metal layer 4 and the metal part 5 exists in the region D at a distance of L / 6 from any one of the four corners of the heat dissipation member 1C.

[0161] The reason why the volume of the surface metal layer 4 is included in the volume of the metal part 5 is as described above, because there may be no "boundary" between the surface metal layer 4 and the metal part 5.

[0162] Figure 9 In (b), the thickness of the surface metal layer 4 is, for example, about 100 μm or more and 300 μm or less in total for the upper and lower sides.

[0163] In addition, a plating layer ( Figure 9 not shown) may also exist on the surface of the surface metal layer 4. The plating layer can be, for example, a Ni plating. The thickness of the plating layer can be about 10 μm for each layer, and about 20 μm in total for the upper and lower sides.

[0164] In the third embodiment, for example, the following aspects can be basically the same as those of the first embodiment or the second embodiment. Therefore, repeated descriptions are omitted.

[0165] · In terms of the aspect that the peripheral part of the heat dissipation member 1C can be continuously provided with the metal part 5

[0166] · In terms of the aspect that the part other than the metal part 5 (and the part other than the surface metal layer 4) in the heat dissipation member 1C is composed of the composite part 2 (composite part 2) in which metal is impregnated in silicon carbide having voids

[0167] In addition, regarding the features not clarified above, the manufacturing method of the heat dissipation member 1C, etc., can also be basically the same as those of the first embodiment, etc.

[0168] Regarding the manufacturing method, it should be added that the surface metal layer 4 can be formed by improving the process of impregnating the metal into the formed body and the inorganic fibers to form the composite part 2 and the metal part 5 in the manufacturing method of the heat dissipation member 1 in the first embodiment. For example, it can be formed by improving the shape of the concave die and / or the convex die in this process (3), and more specifically, it can be formed by setting a "gap" equivalent to the surface metal layer 4 between the mold and the formed body.

[0169] <Fourth Embodiment>

[0170] Figure 10 It is a schematic diagram for explaining the heat dissipation member (heat dissipation member 1D) of the fourth embodiment. It shows the situation of looking down on the heat dissipation member 1D with one main surface as the upper surface.

[0171] Each of the metal parts 5 at the corners of the heat dissipation member 1D has 2 holes 3, for a total of 8 holes 3 (through holes provided in the thickness direction of the heat dissipation member 1D). By having a total of 8 holes 3, the heat dissipation member 1D can be more firmly fixed to other components using screws or the like. In addition, since the force applied to each screw is dispersed compared to the case of fixing the heat dissipation member to other components with 4 screws, it is considered that cracks and fractures around the holes 3 can be further reduced.

[0172] In the fourth embodiment, in the following aspects, it can be basically the same as the first embodiment, the second embodiment, or the third embodiment. Therefore, repeated descriptions are omitted.

[0173] · Regarding the aspect that the peripheral part of the heat dissipation member 1D can continuously be provided with the metal part 5

[0174] · Regarding the aspect that the part other than the metal part 5 (and the part other than the surface metal layer 4) in the heat dissipation member 1D is composed of the composite part 2 (composite part 2) obtained by impregnating metal into silicon carbide with voids

[0175] · Regarding the aspect that the ratio of the volume of the metal part 5 to the overall volume of the heat dissipation member 1D is 2.9% or more and 12% or less

[0176] · Regarding the aspect that 40% or more of the total volume of the metal part 5 exists in the region D at a distance of L / 6 from any vertex of the four corners of the heat dissipation member 1D

[0177] Regarding the features not clarified above, the manufacturing method of the heat dissipation member 1D, etc., can also be basically the same as the first embodiment, etc.

[0178] The embodiments of the present invention have been described above, but these embodiments are merely examples of the present invention, and various configurations other than those described above may be adopted. In addition, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are all included in the present invention.

[0179] Example

[0180] The embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted that the present invention is not limited to the examples.

[0181] (Fabrication of heat dissipation member)

[0182] Commercially available high-purity silicon carbide powder A (average particle size: 200 μm), silicon carbide powder B (average particle size: 20 μm), and silica sol (manufactured by Nissan Chemical Industries, Ltd.: SNOWTEX) were mixed at a mass ratio of 70:40:5 and mixed with a stirring mixer for 1 hour to obtain a mixed powder.

[0183] A pressure of 10 MPa was applied to the mixed powder to form a flat plate shape as follows: a flat plate with a size of 160 mm × 120 mm × 7 mm and notch portions of the sizes shown in the following table at the four corners. It was dried at a temperature of 100 °C for 2 hours, and then heated in the atmosphere at 900 °C for 2 hours to fabricate a silicon carbide molded body. It should be noted that the notch portions were filled with aluminum short fibers (ceramic fibers of mullite material, "ALCEN (registered trademark)" manufactured by Denka Co., Ltd.) in the amounts recorded in the following table.

[0184] It should be noted that the obtained silicon carbide molded body was processed into a shape, and the relative density was calculated from its size and mass. The relative density was 65%.

[0185] Then, the obtained silicon carbide molded body was processed to a thickness of 4.8 mm with a diamond processing jig, and SUS plates coated with a release agent were sandwiched between 10 specimens each, and further fixed with bolts and nuts to an iron plate with a thickness of 12 mm to form a block.

[0186] One block was composed of 4 of the above-mentioned blocks, preheated to a temperature of 650 °C in an electric furnace, and then placed in a mold having a preheated void with internal dimensions of 320 mm × 260 mm × 440 mm.

[0187] Then, a molten aluminum alloy (containing 12 mass% silicon and 0.5 mass% magnesium) heated to a temperature of 800 °C was poured into the mold, and pressed at a pressure of 60 MPa for 20 minutes or more to impregnate the aluminum metal into the silicon carbide molded body.

[0188] Cool the metal block containing the composite obtained by the above process to room temperature, and then cut it with a wet band saw to obtain a flat metal-silicon carbide composite with a size of 170 mm × 130 mm × 5 mm, which includes a composite part composed of aluminum alloy and silicon carbide and a metal part of aluminum alloy.

[0189] Then, machine the outer periphery of the obtained metal-silicon carbide composite to 162 mm × 122 mm (that is, machine it so that, compared with the size of the silicon carbide green body before impregnation, a metal of +1 mm is formed at the peripheral part). Then, machine holes (through holes) with a diameter of 7.0 mm at the four corner parts respectively to fabricate a plate-shaped heat dissipation member as Figure 1 shown. More specifically, as described below.

[0190] (i) In Examples 1 to 12, Examples 15 to 18, and Comparative Examples 1 and 2, the position of the hole is at the position where the center of the notch part in the silicon carbide green body before metal impregnation coincides with the center of the hole (through hole). For example, in Example 1, a hole with a diameter of 7.0 mm is provided at the center of a 17 mm × 17 mm square area corresponding to the part with the notch part.

[0191] (ii) In Example 13, considering the size of the notch part in the silicon carbide green body before metal impregnation, a hole with a diameter of 7.0 mm is provided at the center of an 8 mm × 8 mm square area, which is the sum of the 7 mm × 7 mm metal part corresponding to the part with the notch part and the +1 mm metal part at the peripheral part.

[0192] (iii) In Example 14, similar to Example 13, a hole with a diameter of 7.0 mm is provided at the center of a 7.5 mm × 7.5 mm square area, which is the sum of the 6.5 mm × 6.5 mm metal part corresponding to the part with the notch part and the +1 mm metal part at the peripheral part.

[0193] That is, in each example and comparative example, the through hole is formed in the part where the metal part is formed.

[0194] For the obtained heat dissipation member, measure each dimension as Figure 11 shown using an industrial microscope. In addition, measure the thickness of the metal part using a micrometer, calculate the volume of the metal part, and calculate the volume ratio of the metal layer to the entire heat dissipation member. In addition, calculate various values from the above values, the size of the originally provided notch part, etc.

[0195] (Performance evaluation)

[0196] The heat dissipation members of each example and comparative example were respectively fastened to an aluminum plate sized 170 mm × 130 mm × 10 mm with holes having a diameter of 7.0 mm at the four corners using bolts and nuts. At this time, the torque for fastening with a torque wrench was 15 N·m.

[0197] Then, each heat dissipation member installed with the aluminum plate was subjected to 300 thermal cycles with one cycle being 30 minutes at -40°C and 30 minutes at 150°C. Then, the fixation to the aluminum plate was released.

[0198] Next, an ultrasonic flaw detector (manufactured by Hitachi Construction Machinery Co., Ltd.: FS - Line) was used to measure the periphery of the fastening part (holes) at the four corners and the vicinity of the interface between the composite part and the metal part to investigate whether defects occurred. In addition, a 10 - fold magnifying glass was used to confirm from the surface side whether cracks and fractures occurred.

[0199] The properties of the heat dissipation members and the silicon carbide green body before metal impregnation are summarized in Table 1.

[0200] In addition, the evaluation results are summarized in Table 2.

[0201]

[0202] Table 2

[0203]

[0204] In the evaluations of Examples 1 to 18, after the thermal cycle, no cracks, fractures, etc. were found around the fastening part, at the interface between the composite part and the metal part, etc. That is, even in a very severe evaluation of 300 thermal cycles of 30 minutes at -40°C and 30 minutes at 150°C, no abnormalities were seen, indicating that it can meet the recent stringent reliability requirements for heat dissipation members.

[0205] The heat dissipation members of Examples 1 to 18 suppress the occurrence of thermal stress during thermal cycling by improving the toughness around the through - holes for fixing to other components and making the proportion of the metal layer formed with through - holes small enough with respect to the entire composite body, and also suppress breakages such as cracks and fractures during fixation to other components and during actual use after fixation.

[0206] On the other hand, in Comparative Examples 1 and 2, the proportion of the metal part with respect to the entire heat dissipation member exceeded 12% by volume, and cracks and fractures occurred in the composite part and at the interface between the composite part and the metal part after the thermal cycle.

[0207] (Examples 19 and 20: Examples of using magnesium)

[0208] The bulk of the silicon carbide formed body with a notch portion produced in the same manner as in Examples 1 and 2 (10 silicon carbide formed bodies, the material fixed with bolts and nuts) was preheated to a temperature of 600 °C using an electric furnace. It was placed in a preheated mold having a void with internal dimensions of 320 mm × 260 mm × 440 mm.

[0209] Then, a molten liquid of pure magnesium heated to a temperature of 800 °C was poured into the mold, and it was pressed under a pressure of 60 MPa for 20 minutes or more to impregnate magnesium into the silicon carbide formed body and the aluminum short fibers. Except for this, the same operations as in Examples 1 and 2 were carried out for metal impregnation, pore formation, etc. to manufacture a heat dissipation member. Then, the same evaluation as above was carried out.

[0210] In Examples 19 and 20, no cracks, fractures, etc. were observed around the fastening portion, the composite portion, and the interface between the composite portion and the metal layer. That is, it was shown that even when magnesium is used instead of aluminum as the metal, the severe reliability requirements for heat dissipation members in recent years can be satisfied.

[0211] This application claims priority based on Japanese Patent Application No. 2018 - 223830 filed on November 29, 2018, and incorporates the entire contents disclosed therein into this application.

Claims

1. A heat dissipation member, which is a heat dissipation member substantially in the shape of a rectangular flat plate, The heat dissipation member includes a composite portion in which a metal is impregnated in silicon carbide having voids, and a metal portion different from the composite portion, The ratio of the volume of the metal portion to the total volume of the heat dissipation member is 2.9% or more and 12% or less, When the length of the diagonal of the heat dissipation member is L and the heat dissipation member is viewed from above with one main surface as the upper surface, 40% or more of the total volume of the metal portion exists in a region D at a distance of L / 6 from any vertex of the four corners of the heat dissipation member, The heat dissipation member has a hole penetrating the metal portion in the region D.

2. The heat dissipation member according to claim 1, wherein The thickness of the metal portion existing in the region D is substantially equal to the thickness of the composite portion.

3. The heat dissipation member according to claim 1 or 2, wherein Let the volume of the metal part existing in the region D be V 金属 , and let the volume of the hole be V 孔 . When V 孔 / (V 金属 + V 孔 ), the value is 0.60 or less.

4. The heat dissipation member according to claim 1 or 2, wherein When the radius of the hole when the heat dissipation member is viewed from above with one main surface of the heat dissipation member as the upper surface is r, the composite portion does not exist in a region within a distance of 1.3r from the center of the hole.

5. The heat dissipation member according to claim 1 or 2, wherein When the heat dissipation member is viewed from above with one main surface of the heat dissipation member as the upper surface, the hole does not exist in a region within a distance of L / 40 from the vertices of the four corners of the heat dissipation member.

6. The heat dissipation member according to claim 1 or 2, wherein A part of the metal portion is continuously provided at the peripheral portion of the heat dissipation member.

7. The heat dissipation member according to claim 1 or 2, wherein, When the heat dissipation member is viewed from above with one main surface of the heat dissipation member as the upper surface, The metal portion includes a first metal portion and a second metal portion. The first metal portion includes at least a part of the peripheral portion of the heat dissipation member, and the second metal portion does not contact the peripheral portion and the first metal portion of the heat dissipation member, The second metal portion exists in a range of L / 55 to L / 5 from the nearest vertex within the heat dissipation member, The hole penetrates the second metal portion.

8. The heat dissipation member according to claim 1 or 2, wherein The metal portion includes inorganic fibers mainly composed of alumina or silica.

9. The heat dissipation member according to claim 1 or 2, wherein The relative density of the silicon carbide is 55% or more and 75% or less.

10. The heat dissipation member according to claim 1 or 2, wherein, The metal impregnated in the composite portion is the same metal as the metal contained in the metal portion.

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