Thermal conductors, heat spreaders and heat dissipation structures

Abstract

To provide a thermal conductor capable of forming a heat flow path between adjacent diamonds and hardly deforming another member when joined to the other member. [Solution] The heat conductor 100 of the present invention has a diamond-containing metal layer 20 including a plurality of diamonds 40 arranged in one layer and a metal 42 that fixes the diamonds 40, and the diamonds 40 are polyhedrons with octahedrons or more, do not protrude from the diamond-containing metal layer 20, and are in surface contact with adjacent diamonds 40. One surface 20S of the diamond-containing metal layer 20 is a smoothed surface. Also, the end 40B of the diamond 40 on the other surface 20B side of the diamond-containing metal layer 20 is a vertex or edge, or the other surface 20B of the diamond-containing metal layer 20 is a smoothed surface, and the end of the diamond 40 on the other surface 20B side before smoothing is a vertex or edge.

Description

[Technical field]

[0001] The present invention relates to a thermal conductor and a heat spreader, and also to a heat dissipation structure including the heat spreader. [Background technology]

[0002] It is known that diamond, which has excellent thermal conductivity, is used to improve the performance of heat sinks and heat spreaders.For example, Patent Document 1 discloses an insulating and heat transfer structure that includes an insulating layer and a high thermal conductor layer arranged on both sides of the insulating layer, and the insulating layer has a bonding layer and insulating and highly thermally conductive hard particles protruding from the high thermal conductor layer, characterized in that a particle group in which the insulating and highly thermally conductive hard particles are arranged at equal intervals in one direction in the in-plane direction of the bonding layer, is arranged at equal intervals in a plurality of groups in the in-plane direction in a different direction, and diamond is described as one of the insulating and highly thermally conductive hard particles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-214492 A Summary of the Invention [Problem to be solved by the invention]

[0004] By using a structure with a layer of diamonds between the heat source and the heat sink, the heat flow path (vertical route) from the heat source to the heat sink can be improved. However, in the structure of Patent Document 1, the diamonds are spaced apart and there is no heat transfer between the diamonds (horizontal route), so it cannot be said that the heat transfer performance of diamonds is fully utilized.

[0005] Also, the heat sink and the heat spreader are generally bonded with adhesives such as thermally conductive grease and heat dissipation gap filler. As shown in FIG. 11, when the heat sink 3 and the heat spreader 14 are bonded, the recesses 60 on the surfaces of the heat sink 3 and the heat spreader 14 are filled with adhesives 5 such as thermally conductive grease and heat dissipation gap filler, and the voids in the recesses 60 are filled with air pockets (air gaps), so that heat is transmitted well. However, since diamond is a hard material, if the diamonds 4b protrude from the surface of the heat spreader 14, when the heat sink 3 is bonded to the heat spreader 14, the heat sink 3 may be pushed by the tip of the diamonds 4b, resulting in an irregular hole 3H. Then, when the hole 3H is formed in the heat sink 3 pressed by the diamonds 4b, the adhesive 5 is pushed out, and the shape of the hole 3H is also irregular, so that the adhesive 5 may be insufficient. This may also result in an air pocket being formed, which may reduce the thermal conductivity.

[0006] Under such circumstances, the present invention aims to provide a thermal conductor and a heat spreader that can form a heat flow path between adjacent diamonds and that is unlikely to deform other members when joined to them, and a heat dissipation structure that includes the heat spreader. [Means for solving the problem]

[0007] The thermal conductor of the present invention is a thermal conductor having a diamond-containing metal layer that contains a plurality of diamonds arranged in a layer and a metal that fixes the diamonds, and satisfies the following (I), (II), and (III-1) or (III-2): (I) The diamond is an octahedral or higher polyhedron, does not protrude from the diamond-containing metal layer, and is in face-to-face contact with adjacent diamonds. (II) One surface of the diamond-containing metal layer is a smoothed surface so that the end of the diamond on that side of the diamond-containing metal layer is flush with the one surface of the diamond-containing metal layer. (III-1) The end of the diamond on the other surface side of the diamond-containing metal layer is the apex or edge of the diamond. (III-2) The other surface of the diamond-containing metal layer is a surface which has been smoothed so that the end of the diamond on the other surface side is flush with the other surface, and the end of the diamond on the other surface side before smoothing is an apex or a ridge line.

[0008] A diamond-containing metal layer with such a structure can be obtained by smoothing at least the upper surface of a layer in which multiple diamonds, which are octahedral or higher polyhedrons and arranged in a single layer with their apexes or edges facing down, are fixed with the metal.

[0009] In this way, by arranging diamonds with octahedrons or more in a single layer, it is possible to make the structure thinner. Moreover, by allowing adjacent diamonds to be in face-to-face contact while increasing the exposed area of ​​the diamonds, in addition to the heat flow path (vertical route) from the heat source, a heat flow path (horizontal route) is formed between the diamonds, allowing heat to be diffused more widely and enabling the heat transfer performance of the diamonds to be fully utilized.

[0010] In addition, when it is joined to another member, it is possible to make it difficult to damage the other member. For example, when it is combined with a heat sink and a heat source, the hard diamond is adapted to the surface shape of the other side (heat sink and heat source), so that it is possible to avoid causing unexpected damage (formation of a recess) to the other side due to the hardness of the diamond. Since diamond is less deformed by heat, but the other side is not, if the diamond damages the other side (formation of a recess), even if there is no air gap when there is no deformation by heat, when deformation by heat occurs, there is a possibility that an air gap will be generated due to deformation of the damaged (formation of a recess) part. However, since the thermal conductor of the present invention is unlikely to cause unexpected damage (formation of a recess), by filling the air gap with an adhesive such as thermal conductive grease or heat dissipation gap filler when there is no deformation by heat, there is a high expectation that the filling will be maintained even if deformation by heat occurs. Specifically, as shown in FIG. 10, when a heat spreader 12 made of the thermal conductor of the present invention is pressed against a heat sink 3 and joined, it is difficult for an unexpected hole to be generated in the heat sink 3 by the diamond 4a. In addition, even if the heat sink 3 thermally expands, irregular expansion is reduced, and air gaps are unlikely to occur even in a situation where the adhesive 5 between the heat sink 3 and the heat spreader 12 is slightly insufficient. This increases the possibility that high thermal conductivity in the vertical direction can be maintained even when deformation due to heat begins.

[0011] In addition, by arranging the diamonds so that the end of the other surface side of the diamond-containing metal layer of the diamond, or the end of the other surface side of the diamond-containing metal layer of the diamond before smoothing becomes a vertex or a ridgeline (hereinafter, the "vertex or ridgeline" may be referred to as the "edge portion"). This makes it easier to bring adjacent diamonds into surface contact with each other regardless of the shape or alignment of the orientation of the diamonds, and increases the degree of freedom in the shape of the diamonds used, thereby increasing the degree of freedom in production. Furthermore, the area where adjacent diamonds come into surface contact with each other increases. This increases the thermal conduction in the heat flow path (horizontal route) between the diamonds, making it easier for heat to diffuse.

[0012] In addition, "vertex" is a point shared by three or more sides (ridgelines) of a diamond, and "ridgeline" is a line connecting the vertices of a diamond. In addition, in the present application, "end" means the part farthest from the center in the thickness direction. For example, "end of one surface side of diamond-containing metal layer of diamond" means the part farthest from the center in the thickness direction of diamond-containing metal layer in diamond-containing metal layer, and when the vertex of diamond is the part farthest in the direction of one surface of diamond-containing metal layer, the end of one surface side of diamond-containing metal layer of diamond is vertex, when the ridgeline of diamond is the part farthest in the direction of one surface of diamond-containing metal layer, the end of one surface side of diamond-containing metal layer of diamond is ridgeline, and when the surface of diamond is the part farthest in the direction of one surface of diamond-containing metal layer, the end of one surface side of diamond-containing metal layer of diamond is face. "The end of the diamond on the other side of the diamond-containing metal layer" means the part of the diamond that is furthest from the center in the direction of the other side of the diamond-containing metal layer in the thickness direction of the diamond-containing metal layer; when the apex of the diamond is the part that is furthest in the direction of the other side of the diamond-containing metal layer, the end of the diamond on the other side of the diamond-containing metal layer is the apex, when the ridgeline of the diamond is the part that is furthest in the direction of the other side of the diamond-containing metal layer, the end of the diamond on the other side of the diamond-containing metal layer is the ridgeline, and when the face of the diamond is the part that is furthest in the direction of the other side of the diamond-containing metal layer, the end of the diamond on the other side of the diamond-containing metal layer is a face.

[0013] In the thermal conductor of the present invention, it is preferable that the ratio of the exposed area of ​​the diamond to one surface of the diamond-containing metal layer is 30% or more. By increasing the exposed area of ​​diamond, the efficiency of heat inflow to or outflow from the diamond-containing metal layer is increased, and the thermal conductivity can be increased. Also, since the diamond exposed on the face, rather than on the apex or edge (i.e., point or line), can be increased, heat can be efficiently transferred to one face of the diamond-containing metal layer and the adjacent portion.

[0014] In order to further enhance thermal conductivity, it is preferable that the thermal conductor of the present invention satisfies (I), (II) and (III-2) above, and that the proportion of the exposed area of ​​the diamond on the other face of the diamond-containing metal layer is 30% or more. By increasing the exposed area of ​​diamond on both sides of the diamond-containing metal layer, heat can be more easily introduced into and released from the diamond-containing metal layer, further increasing thermal conductivity.

[0015] Furthermore, in the thermal conductor of the present invention, the diamond is in the shape of a truncated octahedron with some of the apexes or edges cut off, or a hexagonal octahedron with some of the apexes or edges cut off, and the diamond (i) has one cut-off face, which is flush with one face of the diamond-containing metal layer, or (ii) has two cut-off faces, one of which is flush with one face of the diamond-containing metal layer and the other of which is flush with the other face of the diamond-containing metal layer. Such a structure can be obtained by arranging truncated octahedral or hexagonal diamonds in a single layer and smoothing at least one face of the diamond-containing metal layer. By using truncated octahedral or hexagonal diamonds, the diamonds can be arranged at a higher density, further increasing the heat flow paths between the diamonds.

[0016] Furthermore, the thermal conductor of the present invention comprises a thermally conductive member having a flat surface, and the diamond-containing metal layer arranged on at least one side of the flat surface, and it is preferable that the diamond-containing metal layer is arranged so that one side of the diamond-containing metal layer is opposite to the side on which the flat surface is located. With this configuration, it is possible to prevent damage to other members when they are joined together. Furthermore, by combining the heat conductor with a thermally conductive member, the degree of freedom in designing the shape of the heat conductor can be increased.

[0017] The thermal conductor of the present invention can be used as a heat spreader. That is, the heat spreader of the present invention is made of the thermal conductor of the present invention.

[0018] The thermal conductor of the present invention can be incorporated into a heat dissipation structure, which includes the heat spreader of the present invention, which is disposed on and thermally connected to a heat source, and a heat sink, which is disposed on and thermally connected to the heat spreader. With this configuration, deformation of the heat source and heat sink by the diamond in the heat spreader is prevented, and heat flowing from the heat source into the heat spreader can be efficiently transferred from the heat spreader to the heat sink, resulting in a heat dissipation structure with excellent heat dissipation properties. Effect of the Invention

[0019] According to the present invention, there is provided a thermal conductor and a heat spreader that can form a heat flow path between adjacent diamonds and is less likely to deform other components when joined to the other components, as well as a heat dissipation structure that includes the heat spreader. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of a thermal conductor according to an embodiment of the present invention. [Diagram 2] 2A to 2C are diagrams for explaining a method for producing the thermal conductor of FIG. 1. [Diagram 3] FIG. 4 is a schematic diagram of a thermal conductor according to another embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram of a thermal conductor according to another embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram of a thermal conductor according to another embodiment of the present invention. [Figure 6] FIG. 4 is a schematic diagram of a thermal conductor according to another embodiment of the present invention. [Figure 7] 1 is a schematic diagram of a heat dissipation structure according to an embodiment of the present invention. [Figure 8] 8 is a diagram for explaining the configuration of the heat dissipation structure of FIG. 7 in more detail. [Figure 9] FIG. 4 is a schematic diagram of a heat dissipation structure according to another embodiment of the present invention. [Figure 10] 5A to 5C are diagrams for explaining how a heat sink and a heat spreader of the present invention are joined together. [Figure 11] 11A and 11B are diagrams for explaining a state in which a heat sink and a conventional heat spreader are joined together. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, the embodiment of the present invention will be described in detail with reference to Figs. 1 to 9. However, the description of the constituent elements described below is one example (representative example) of the embodiment of the present invention, and the present invention is not limited to the following content as long as the gist of the present invention is not changed. In addition, when the expression "-" is used in this specification, it is used as an expression including the numerical value or physical property value before and after it. In addition, the same reference numerals are used for the parts common to Figs. 1 to 9, and the description will be omitted.

[0022] <Embodiment 1> Fig. 1 is a schematic diagram of a thermal conductor 100 according to the present invention. The thermal conductor 100 shown in Fig. 1 is a plate-like body made of a diamond-containing metal layer 20 containing a plurality of diamonds 40 arranged in one layer and a metal 42 for fixing the diamonds 40. Furthermore, the diamonds 40 do not protrude from the diamond-containing metal layer 20, and adjacent diamonds 40 are in face-to-face contact with each other.

[0023] In the diamond-containing metal layer 20, the surface 20S, which is one surface of the diamond-containing metal layer 20, is a surface that has been smoothed so that the end 40S of the diamond 40 on the surface 20S side (i.e., the surface of the diamond 40 exposed on the surface 20S) is flush with the surface 20S. Furthermore, the proportion of the exposed area of ​​the diamond 40 on the surface 20S of the diamond-containing metal layer 20 is 30% or more (for example, 30% or more and less than 100%). This exposed area of ​​the diamond 40 can be obtained, for example, by photographing the surface 20S of the diamond-containing metal layer 20 with a microscope such as a digital microscope and from this photographed image.

[0024] Moreover, the diamond 40 is arranged so that the end 40B on the side of the face 20B, which is the other face of the diamond-containing metal layer 20, becomes an edge part. In other words, only the edge part of the diamond 40 contacts the face 20B of the diamond-containing metal layer 20.

[0025] As described later, as shown in Fig. 2, the diamond-containing metal layer 20 is formed by smoothing the upper surface 21S of a layer 21 in which a number of truncated octahedral diamonds 40b are arranged in a single layer with their vertices or ridges (edges) facing down (towards the substrate 44) and fixed with a metal 42, by polishing or other processing. By performing processing such as polishing, the unevenness of the surface 21S is made perfectly smooth. At this time, by arranging the diamonds 40b so that their hexagonal faces come into surface contact with each other, the lateral contact area can be made large.

[0026] In the diamond-containing metal layer 20, the diamond 40 is a truncated octahedron with a part of its apex or ridge cut off. Specifically, as shown in FIG. 2, the upper side of a row of truncated octahedron diamonds arranged in a layer on the substrate 44 with their edges facing down is cut off by a plane parallel to the surface of the substrate 44, and the diamond 40 has one face of the cut off part, which is the end 40S (i.e., the face of the diamond 40 exposed on the face 20S) and is the same plane as the face 20S of the diamond-containing metal layer 20. At this time, the faces of the diamond 40 other than the 100 face and the 111 face are exposed on the face 20S.

[0027] In the diamond-containing metal layer 20, the majority of the diamonds 40 have the end 40B as the edge part E, and some of the diamonds 40 may have the end 40B as a surface. The proportion of diamonds 40 whose end 40B is the edge part E and which are in surface contact with adjacent diamonds 40 is, specifically, 50% or more of the diamonds contained in the diamond-containing metal layer 20, preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. The shape of the end 40B of the diamond and the presence or absence of surface contact with adjacent diamonds can be determined, for example, by observing the diamond-containing metal layer 20 with a microscope, and can be evaluated by exposing the diamond 40 on the front or back side as necessary and then observing with the microscope.

[0028] (Production Example 1) The thermal conductor of the present invention can be obtained, for example, by a method including the steps of arranging a plurality of diamonds in a layer on a substrate with the edges of the diamonds facing the substrate, plating the substrate on which the diamonds are arranged to form a plating layer, and smoothing the surface of the plating layer by processing such as polishing to form a diamond-containing metal layer. In the case of thermal conductor 100, the substrate and diamond-containing metal layer are separated after smoothing the surface of the plating layer.

[0029] The manufacturing method of the thermal conductor 100 will be specifically described with reference to Fig. 2. First, diamonds 40b (diamonds before processing such as polishing) are filled onto a substrate 44 while being subjected to vibration, and the diamonds 40b are densely arranged with their edges E facing down in a state of surface contact with adjacent diamonds 40b (Fig. 2(A)). The substrate 44 may be made of metals such as stainless steel, copper, aluminum, steel, cemented carbide, molybdenum, molybdenum alloy, cermet, and titanium, ceramics, plastics, etc.

[0030] The diamond 40b (diamond before processing such as polishing) is preferably appropriately selected from those having an average grain size of 35 μm to 1000 μm. The ratio of diamonds 40b having a grain size within ±15% of the average grain size is preferably 90% or more, more preferably 93% or more, and even more preferably 95% or more. By using diamonds 40b having a uniform grain size in this way, it is easy to form a structure in which diamonds 40b are arranged at a higher density with the edge part E of diamond 40 facing the substrate 44. This average grain size is the average grain size of 100 diamonds 40b, and the grain size of each diamond 40b is the average value of the long side and the short side of the circumscribing rectangle. When calculating this average grain size, the ratio of diamonds 40b having a grain size within ±15% of the average grain size described below can also be obtained.

[0031] Next, metal 42 is deposited on substrate 44 by plating, so that diamond 40b is fixed by metal 42, and plating layer 21 (diamond-containing metal layer before processing such as polishing) is formed on substrate 44 (FIG. 2(B)). As metal 42, nickel and its alloys are preferable, and examples thereof include Ni, Ni-S alloy, Ni-P alloy, Ni-B alloy, and Ni-Co alloy.

[0032] In Fig. 2(B), the metal 42 is plated so that the diamonds 40b protrude, but the plating process is not limited to this. The metal 42 may be plated so that the diamonds 40b are covered. In consideration of the stability and productivity of the fixed diamonds 40, the plating thickness is preferably about 35 to 95% of the average grain size of the diamonds 40b.

[0033] Next, the surface (face 21S) of the plating layer 21 formed on the substrate 44 is smoothed by processing such as polishing to form the diamond-containing metal layer 20 (FIG. 2(C)). Processing such as polishing is performed until the diamonds 40 do not protrude and the exposed area of ​​the diamonds 40 on the surface (face 20S) of the formed diamond-containing metal layer 20 is 30% or more.

[0034] Then, after processing such as polishing, the stainless steel substrate 44 and the diamond-containing metal layer 20 are separated to obtain the diamond-containing metal layer 20 (FIG. 2(D)). One surface, 20S, of the obtained diamond-containing metal layer 20 is smoothed by processing such as polishing, and the other surface, 20B, is also smooth because it is a surface formed along the substrate 44. Therefore, when it is joined to another member, it is unlikely to deform the other member.

[0035] As described below, the diamond-containing metal layer 20 may be used without being separated from the substrate 44, and when the thermal conductor 100 is combined with another member such as a heat sink, the thermal conductor 100 may be formed directly on the other member.

[0036] In addition, in the heat conductor according to the present invention, the end of the diamond arranged on one side of the diamond-containing metal layer is on the same plane as one side of the diamond-containing metal layer. That is, the face or edge of the diamond is on the same plane as one side of the diamond-containing metal layer. However, from the viewpoint of thermal conductivity, it is preferable that the face of the diamond is on the same plane as one side of the diamond-containing metal layer, and it is more preferable that the exposed area of ​​the diamond is 30% or more.

[0037] <Embodiment 2> Fig. 3 is a schematic diagram of a thermal conductor 110 according to the present invention. The thermal conductor 110 shown in Fig. 3 is a plate-like body made of a diamond-containing metal layer 22 containing a plurality of diamonds 46 arranged in one layer and a metal 42 that fixes the diamonds 46. Adjacent diamonds 46 are in surface contact with each other.

[0038] In the diamond-containing metal layer 22, the surface 22S, which is one surface, is a surface that has been smoothed so that the end 46S of the diamond 46 on the surface 22S side (i.e., the surface of the diamond 46 exposed on the surface 22S) is flush with the surface 22S, and the ratio of the exposed area of ​​the diamond 46 on the surface 22S is 30% or more (e.g., 30% or more and less than 100%). In addition, the surface 22B, which is the other surface of the diamond-containing metal layer 22, is a surface that has been smoothed so that the end 46B of the diamond 46 on the surface 22B side (i.e., the surface of the diamond 46 exposed on the surface 22B) is flush with the surface 22B, and the ratio of the exposed area of ​​the diamond 46 on the surface 22B is 30% or more (e.g., 30% or more and less than 100%).

[0039] The diamond-containing metal layer 22 is obtained by smoothing the surface 20B of the diamond-containing metal layer 20 in FIG. 1 by processing such as polishing so that the ratio of the exposed area of ​​the diamond 46 on the surface 22B is 30% or more. That is, a plurality of truncated octahedron-shaped diamonds 40b arranged in one layer with the edge part E facing down are fixed by the metal 42, and both sides of the layer are smoothed by processing such as polishing. Therefore, the end of the diamond 46 on the surface 22B side before smoothing (i.e., 40B in FIG. 1) is a vertex or a ridgeline. The presence or absence of smoothing can be judged from the traces of processing such as polishing on the smoothed surface and the shape of the diamond after smoothing, and the shape of the end of the diamond before smoothing can be judged from the shape of the diamond after smoothing. Specifically, if the intersection point when the ridgeline that contacts the other surface of the diamond after smoothing is extended is on the other surface before smoothing, it can be estimated that the end of the diamond on the other surface side before smoothing is a vertex or a ridgeline.

[0040] In the diamond-containing metal layer 22, the diamond 46 is a truncated octahedron with a part of its apex or edge cut off. Specifically, the diamond 46 has a structure in which the upper and lower sides of a row of truncated octahedron diamonds arranged in a layer with the edge part facing downward are cut off by opposing parallel faces, and the diamond 46 has two faces of the cut off part, one of which is an end 46S and is flush with the face 22S of the diamond-containing metal layer 22, and the other is an end 46B and is flush with the face 22B of the diamond-containing metal layer 22.

[0041] The shape of diamond is not particularly limited as long as it is an octahedron or more and has a surface that is flush with one surface of the diamond-containing metal layer.From the viewpoint of easily achieving a higher density arrangement of diamonds, the diamond before processing such as polishing is preferably a truncated octahedron or hexagonal octahedron.Therefore, it is preferable that diamond is a truncated octahedron with a part of the apex or edge line cut off, or a hexagonal octahedron with a part of the apex or edge line cut off, and diamond (i) has one cut-off surface, and the cut-off surface is flush with one surface of the diamond-containing metal layer, or (ii) has two cut-off surfaces, and one cut-off surface is flush with one surface of the diamond-containing metal layer, and the other cut-off surface is flush with the other surface of the diamond-containing metal layer.

[0042] <Embodiment 3> Fig. 4 is a schematic diagram of a thermal conductor 120 according to the present invention. The thermal conductor 120 shown in Fig. 4 comprises a thermally conductive member 50 having a flat surface 50X, and a diamond-containing metal layer 20 disposed on one surface of the flat surface 50X. The diamond-containing metal layer 20 has the same configuration as the diamond-containing metal layer 20 of the thermal conductor 100, and is disposed so that a surface 20S is located on the side opposite to the flat surface 50X.

[0043] The heat conductive member 50 is a member formed of a material having heat conductivity, and has a flat portion 50X having a surface parallel to the surface 20B of the diamond-containing metal layer 20. In the heat conductor 120, the heat conductive member 50 is a plate-shaped member consisting of the flat portion 50X, but the shape of the heat conductive member 50 is not particularly limited. The heat conductive member 50 has a flat portion and a wall portion for surrounding a heat source, and may be a box-shaped frame (see FIG. 6) with one side open. When the heat conductive member is a box-shaped frame, the diamond-containing metal layer may be provided on the side opposite the heat source side of the flat portion, or on the heat source side of the flat portion.

[0044] The diamond-containing metal layer 20 and the heat conductive member 50 are bonded and thermally connected. This bonding may be performed by bonding the diamond-containing metal layer 20 and the flat surface portion 50X of the heat conductive member 50 using a thermally conductive adhesive such as thermally conductive grease or a heat dissipating gap filler, or by directly forming the diamond-containing metal layer 20 on the flat surface portion 50X of the heat conductive member 50.

[0045] (Production Example 3-1) An example of a method using a thermally conductive adhesive is to obtain a diamond-containing metal layer 20 in the same manner as in Production Example 1, and then superimpose and bond the flat portion 50X of the thermally conductive member 50 and the surface 20B (the surface facing the substrate 44) of the diamond-containing metal layer 20 together with a thermally conductive adhesive.

[0046] (Production Example 3-2) An example of a method for directly forming the diamond-containing metal layer 20 on the flat portion 50X of the heat conductive member 50 is to use the heat conductive member 50 as the substrate 44 and to fill with diamond 40 in Production Example 1 and perform plating treatment.

[0047] In addition, in the heat conductor 120, the diamond-containing metal layer 20 is arranged so that the surface 20S of the diamond-containing metal layer 20 is located on the opposite side to the flat surface portion 50X side of the heat conductive member 50, but is not limited thereto. The heat conductor of the present invention may be configured so that the diamond-containing metal layer 20 is arranged so that the surface 20S of the diamond-containing metal layer 20 is located on the flat surface portion 50X side of the heat conductive member 50. A heat conductor of such a structure can be obtained by bonding the flat surface portion 50X and the surface 20S of the diamond-containing metal layer 20 with an adhesive, instead of bonding the flat surface portion 50X and the surface 20B of the diamond-containing metal layer 20 with an adhesive in the manufacturing example 3-1. In addition, in the heat conductor 120, the diamond-containing metal layer 20 may be configured as a diamond-containing metal layer 22.

[0048] <Embodiment 4> FIG. 5 is a schematic diagram of a thermal conductor 130 according to the present invention. The thermal conductor 130 shown in FIG. 5 comprises a diamond-containing metal layer 23, a thermal conductive member 50 having a flat surface 50X disposed on the diamond-containing metal layer 23, and a diamond-containing metal layer 24 disposed on the flat surface 50X of the thermal conductive member 50. The diamond-containing metal layers 23 and 24 have the same configuration as the diamond-containing metal layer 20 of the thermal conductor 100, and the diamond-containing metal layers 23 and 24 are both disposed so that the faces 23S and 24S corresponding to the face 20S of the diamond-containing metal layer 20 are located on the opposite side to the flat surface 50X, and a plurality of diamonds 40 are arranged in one layer with their edges facing the flat surface 50X. The diamond-containing metal layers 23 and 24 are also joined to the thermal conductive member 50 and thermally connected.

[0049] The method for bonding the diamond-containing metal layer 23 and the heat conductive member 50 may be the same as or different from the method for bonding the diamond-containing metal layer 24 and the heat conductive member 50. The heat conductor 130 can be manufactured by appropriately selecting the method of Manufacturing Example 1, Manufacturing Example 3-1, Manufacturing Example 3-2, etc. depending on the orientation of the surface 23S and the surface 24S, and these manufacturing methods may be combined.

[0050] <Embodiment 5> FIG. 6 is a schematic diagram of a heat conductor 140 according to the present invention. The heat conductor 140 shown in FIG. 6 includes a box-shaped heat conductive member 52, a plate-shaped heat conductive member 53, a diamond-containing metal layer 25, a plate-shaped heat conductive member 54, and a diamond-containing metal layer 26. The heat conductive member 52 is a member formed of a material having heat conductivity, and has a flat portion 52X and a wall portion 52Y for surrounding a heat source, and is a box-shaped frame with one side open. The heat conductive members 53 and 54 are plate-shaped members formed of a material having heat conductivity, and the heat conductive member 53 is disposed on one side of the flat portion 52X of the heat conductive member 52, and the heat conductive member 54 is disposed on the other side of the flat portion 52X of the heat conductive member 52. The diamond-containing metal layer 25 is disposed on the opposite side of the heat conductive member 53 from the flat surface 52X, and the diamond-containing metal layer 26 is disposed on the opposite side of the heat conductive member 54 from the flat surface 52X. These members are thermally connected. The diamond-containing metal layers 25 and 26 have the same configuration as the diamond-containing metal layer 20 of the heat conductor 100, and the diamond-containing metal layer 25 is disposed so that the surface 25S corresponding to the surface 20S of the diamond-containing metal layer 20 is disposed on the opposite side of the heat conductive member 53, and the diamond-containing metal layer 26 is disposed so that the surface 26S corresponding to the surface 20S of the diamond-containing metal layer 20 is disposed on the opposite side of the heat conductive member 54.

[0051] (Production Example 5) The heat conductor 140 can be obtained, for example, by bonding a heat conductive member 53 on which a diamond-containing metal layer 25 is formed to one surface of a flat portion 52X of the heat conductive member 52, and bonding a heat conductive member 54 on which a diamond-containing metal layer 26 is formed to the other surface of the flat portion 52X of the heat conductive member 52. Specifically, first, the heat conductive member 53 is used as the substrate 44 of the manufacturing example 3-2 to obtain a heat conductive member 53 on which a diamond-containing metal layer 25 is formed. Separately, the heat conductive member 54 is used as the substrate 44 of the manufacturing example 3-2 to obtain a heat conductive member 54 on which a diamond-containing metal layer 26 is formed. Next, one surface of the flat portion 52X of the heat conductive member 52 and the heat conductive member 53 are bonded to each other using a thermally conductive adhesive, and the other surface of the flat portion 52X of the heat conductive member 52 and the heat conductive member 54 are bonded to each other.

[0052] The orientation of the diamond-containing metal layers 23-26 is not limited to the above configuration. When the heat conductor of the present invention is configured such that diamond-containing metal layers are arranged on both sides of the flat surface of the heat conductive member, the diamond-containing metal layers may each independently face one smoothed surface toward the flat surface side of the heat conductive member, or face the opposite side to the flat surface side. Also, in the heat conductors 130 and 140, one or both of the diamond-containing metal layers may be configured as the diamond-containing metal layer 22.

[0053] <Embodiment 6> The thermal conductor of the present invention can be used as a heat spreader, and can be combined with a heat dissipation member such as a heat sink to form a heat dissipation structure for dissipating heat from a heat source. 7 is a schematic diagram of a heat dissipation structure 200 according to the present invention. The heat dissipation structure 200 shown in FIG. 7 includes a heat spreader 10 disposed on a heat source 1, and a heat sink 3 disposed on the heat spreader 10.

[0054] The heat sink 3 is a member having a base 30 having a surface 30S facing the heat source 1, and for example, a member having the base 30 and a plurality of heat dissipation fins (not shown) erected on the surface of the base 30 opposite the surface 30S. The heat spreader 10 is a member disposed between the heat source 1 and the surface 30S of the base 30 of the heat sink 3. The heat spreader 10 is a thermal conductor of the present invention. By thermally connecting the heat source 1, the heat spreader 10, and the heat sink 3, the heat of the heat source 1 can be transferred from the heat spreader 10 to the heat sink 3 and released to the outside from the heat sink 3.

[0055] For example, the heat dissipation structure 200 may have a structure such as a heat dissipation structure 200a shown in FIG. 8(A), in which the heat spreader 10 is a diamond-containing metal layer 20 (thermal conductor 100) and is joined to a heat source 1 with an adhesive 5 (adhesive having thermal conductivity), and a heat sink 3 joined to the heat spreader 10 with the adhesive 5.

[0056] 8(B), the heat dissipation structure 200 can be a structure including a heat spreader 10 which is a thermal conductor including a heat conductive member 50 having a planar portion 50X, a diamond-containing metal layer 20 bonded to one surface of the planar portion 50X of the heat conductive member 50 with an adhesive 5, and a diamond-containing metal layer 20 bonded to the other surface of the planar portion 50X of the heat conductive member 50 with an adhesive 5, a heat spreader 10 bonded to a heat source 1 with an adhesive 5, and a heat sink 3 bonded to the heat spreader 10 with an adhesive 5.

[0057] 8(C) and 8(D), the heat dissipation structure 200 may be configured such that the diamond-containing metal layer of the thermal conductor of the present invention is directly formed on the heat sink 3. This allows the diamond-containing metal layer to be bonded by electrodeposition.

[0058] The heat dissipation structure 200c shown in Fig. 8(C) has a structure in which the diamond-containing metal layer 20, which is bonded to the heat source 1 by an adhesive 5, is formed directly on the heat sink 3. In this case, the diamond-containing metal layer 20 is the heat spreader 10. In the heat dissipation structure 200c, the heat sink 3 is used as the substrate 44, and after the diamond-containing metal layer 20 is formed directly on the surface 30S of the heat sink 3, the heat sink 3 and the diamond-containing metal layer 20 are used without being separated.

[0059] The heat dissipation structure 200d shown in FIG. 8(D) is a structure including a heat sink 3, a diamond-containing metal layer 20 formed directly on the heat sink 3, a heat conductive member 50 bonded to the diamond-containing metal layer 20 by an adhesive 5, and a diamond-containing metal layer 20 formed directly on the heat conductive member 50, and the diamond-containing metal layer 20 formed directly on the heat conductive member 50 is bonded to the heat source 1 by the adhesive 5. In this case, the laminated portion of the diamond-containing metal layer 20, the heat conductive member 50, and the diamond-containing metal layer 20 is the heat spreader 10. The heat dissipation structure 200d can be obtained by the following method. First, the heat sink 3 is used as a substrate 44, and diamonds are arranged so that their edges face the surface 30S of the heat sink 3, and after plating, the surface is smoothed to form the diamond-containing metal layer 20. Separately, diamonds are arranged so that their edges face one side of the flat portion 50X of the heat conductive member 50, and after plating, the surface is smoothed to form the diamond-containing metal layer 20. Then, the diamond-containing metal layer 20 formed on the heat sink 3 and the heat conductive member 50 are joined with an adhesive 5 .

[0060] <Embodiment 7> The heat dissipation structure of the present invention can be incorporated into electronic devices, etc. Fig. 9 shows an example in which a heat dissipation structure 210 is incorporated as a heat dissipation structure for a CPU die.

[0061] The heat dissipation structure 210 shown in FIG. 9 includes a heat conductor 150, which is a heat spreader, and a heat sink 3. The heat conductor 150 includes a copper plate 70 on which a diamond-containing metal layer 27 is formed, and a box-shaped heat conductive member 52. The diamond-containing metal layer 27 includes a plurality of diamonds 48 arranged in one layer and a metal 42 for fixing the diamonds 48, and the diamonds 48 are octahedral or higher polyhedrons, do not protrude from the diamond-containing metal layer 27, and are in surface contact with adjacent diamonds 48. The surface 27S, which is one surface of the diamond-containing metal layer 27, is a smoothed surface such that an end 48S of the diamond 48 on the surface 27S side (i.e., the surface of the diamond 48 exposed on the surface 27S) is flush with the surface 27S, and an end 48B of the diamond 48 on the other surface side (copper plate 70 side) of the diamond-containing metal layer 27 is a vertex or a ridge. The copper plate 70 on which the diamond-containing metal layer 27 is formed is bonded to both sides of the flat portion 52X of the heat conductive member 52 via a thermally conductive adhesive 5. The heat sink 3 is bonded to the diamond-containing metal layer 27 located outside the flat portion 52X of the heat conductive member 52 by the adhesive 5.

[0062] When used as a heat dissipation structure for the CPU die 1a, the heat dissipation structure 210 is placed on the package substrate 7 so that the wall portion 52Y of the thermally conductive member 52 surrounds the CPU die 1a, and the thermal conductor 150 and the CPU die 1a are bonded together with the adhesive 5. [Industrial Applicability]

[0063] INDUSTRIAL APPLICABILITY The present invention can be used in the field of electronic devices and the like as a thermal conductor for effectively dissipating heat used in heat sinks, heat spreaders, and the like, and is therefore industrially useful. [Explanation of symbols]

[0064] 1 Heat source 1a CPU die 3. Heat sink 3H hole 4a, 4b, 40, 40b, 46, 48 Diamond 5. Glue 7 Package Substrate 10, 12, 14 Heat spreader 20, 21, 22, 23, 24, 25, 26, 27 Diamond-containing metal layer 20S, 20B, 21S, 22S, 22B, 23S, 24S, 25S, 26S, 27S30S side 30 Base 40S, 40B, 46S, 46B, 48S, 48B Ends 42 metal 44 Substrate 50, 52, 53, 54 Thermally conductive member 50X, 52X flat section 52Y wall 60 Recess 70 Copper plate 100, 110, 120, 130, 140, 150 Thermal Conductor 200, 200a, 200b, 200c, 200d, 210 Heat dissipation structure

Claims

1. A heat conductor having a diamond-containing metal layer including a plurality of diamonds arranged in a layer and a metal for fixing the diamonds, A thermal conductor that satisfies the following (I), (II), and (III-1) or (III-2): (I) The diamond is an octahedral or higher polyhedron, does not protrude from the diamond-containing metal layer, and is in face-to-face contact with adjacent diamonds. (II) One surface of the diamond-containing metal layer is a smoothed surface so that the end of the diamond on that side of the diamond-containing metal layer is flush with the one surface of the diamond-containing metal layer. (III-1) The end of the diamond on the other surface side of the diamond-containing metal layer is the apex or edge of the diamond. (III-2) The other surface of the diamond-containing metal layer is a surface which has been smoothed so that the end of the diamond on the other surface side is flush with the other surface, and the end of the diamond on the other surface side before smoothing is an apex or a ridge line.

2. 2. The heat conductor according to claim 1, wherein the diamond-containing metal layer is formed by bonding a plurality of diamonds, which are octahedral or higher polyhedrons, arranged in a single layer with their vertices or edges facing down, with the diamond-containing metal layer having at least the upper surface smoothed.

3. 2. The heat conductor according to claim 1, wherein the ratio of the exposed area of ​​the diamond on one surface of the diamond-containing metal layer is 30% or more.

4. The above (I), (II), and (III-2) are satisfied, 2. The heat conductor according to claim 1, wherein the proportion of the exposed area of ​​the diamond on the other face of the diamond-containing metal layer is 30% or more.

5. The diamond is a truncated octahedron with some of its vertices or edges cut off, or a hexagonal octahedron with some of its vertices or edges cut off, 2. The heat conductor of claim 1, wherein the diamond has (i) one cut-out surface, which is flush with one surface of the diamond-containing metal layer, or (ii) two cut-out surfaces, one of which is flush with one surface of the diamond-containing metal layer and the other of which is flush with the other surface of the diamond-containing metal layer.

6. a thermally conductive member having a planar portion; the diamond-containing metal layer is disposed on at least one surface side of the flat portion; 2. The heat conductor according to claim 1, wherein the diamond-containing metal layer is disposed such that one surface of the diamond-containing metal layer is opposite to the surface on which the flat portion is located.

7. A heat spreader comprising the thermal conductor according to any one of claims 1 to 6.

8. The heat spreader of claim 7 disposed on and thermally bonded to a heat source; a heat sink disposed on and thermally joined to the heat spreader.

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