Thermal conductor, heat spreader, and heat dissipation structure

Abstract

To provide a thermal conductor capable of forming a thermal flow path between adjacent diamonds and hardly deforming other members when joined to the other members.SOLUTION: A thermal conductor 100 according to the present invention includes a diamond-containing metal layer 20 that includes a plurality of diamonds 40 arranged in one layer and a metal 42 that fixes the diamonds 40, and the diamond 40 is a polyhedron of octahedron or more, does not protrude from the diamond-containing metal layer 20, and is in surface contact with the adjacent diamond 40. One surface 20S of the diamond-containing metal layer 20 is a smoothed surface. Further, the end 40B of the diamond 40 on the other surface 20B side of the diamond-containing metal layer 20 is a vertex or a ridgeline, 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 a ridgeline.SELECTED DRAWING: Figure 1

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 comprising an insulator layer and high thermal conductor layers arranged on both sides of the insulator layer, the insulator layer having a bonding layer and insulating, highly thermally conductive hard particles protruding from the high thermal conductor layer, characterized in that a plurality of particle groups in which the insulating, highly thermally conductive hard particles are arranged at equal intervals in one in-plane direction of the bonding layer are arranged at equal intervals in a different direction from the one in-plane direction, and diamond is described as one of the insulating, highly thermally conductive hard particles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-214492 Summary of the Invention [Problem to be solved by the invention]

[0004] By using a structure with a layer of diamonds arranged 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 arranged at intervals, and there is no heat transfer between the diamonds (horizontal route), so it cannot be said that the heat transfer performance of the diamonds is fully utilized.

[0005] Furthermore, heat sinks and heat spreaders are typically bonded using adhesives such as thermally conductive grease or thermal gap fillers. As shown in Figure 11, when bonding a heat sink 3 to a heat spreader 14, adhesive 5, such as thermally conductive grease or thermal gap fillers, fills the recesses 60 on the surfaces of the heat sink 3 and heat spreader 14, filling the voids in the recesses 60 and thereby filling air pockets (air gaps), ensuring efficient heat transfer. However, because diamonds are hard materials, if diamonds 4b protrude from the surface of the heat spreader 14, the heat sink 3 may be pressed against the tips of the diamonds 4b when bonding to the heat sink 3, creating an irregular hole 3H. Furthermore, when the hole 3H is created in the heat sink 3 pressed by the diamonds 4b, the adhesive 5 is pushed out, and the irregular shape of the hole 3H may result in insufficient adhesive 5. This may also create air pockets, potentially reducing thermal conductivity.

[0006] Under these 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 less likely to deform other components when joined to them, as well as 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 includes a plurality of diamonds arranged in a single 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 octahedron 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 the one surface 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 ridge of the diamond. (III-2) The other surface of the diamond-containing metal layer is a surface that 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 a vertex or a ridge line.

[0008] A diamond-containing metal layer with this structure can be obtained by smoothing at least the upper surface of a layer in which multiple diamonds, which are octahedrons or larger polyhedrons and arranged in a single layer with their vertices or edges facing downwards, are fixed with the metal.

[0009] In this way, by arranging diamonds with octahedrons or more in a single layer, the structure can be made thinner, and by increasing the exposed area of ​​the diamonds while allowing adjacent diamonds to be in face-to-face contact, heat flow paths (horizontal routes) are formed between the diamonds in addition to the heat flow paths (vertical routes) from the heat source, allowing heat to be diffused more widely and fully utilizing the heat transfer performance of the diamonds.

[0010] Furthermore, when bonded to other components, the heat conductor is less likely to damage the other components. For example, when combined with a heat sink and a heat source, the hard diamond conforms to the surface shape of the other components (heat sink and heat source), preventing unexpected damage (depression formation) to the other components due to the diamond's hardness. While diamonds are less susceptible to thermal deformation, this is not the case for the other components. Therefore, if the diamond damages the other component (depression formation), even if there is no air gap when there is no thermal deformation, there is a possibility that an air gap will be created due to deformation of the damaged (depression formation) area when thermal deformation occurs. However, since the thermal conductor of the present invention is less likely to cause unexpected damage (depression formation), filling the air gap with an adhesive such as thermal conductive grease or a heat dissipation gap filler when there is no thermal deformation is highly likely to maintain the gap even when thermal deformation occurs. Specifically, as shown in Figure 10, when a heat spreader 12 made of the thermal conductor of the present invention is pressed against a heat sink 3 and bonded, the diamond 4a is less likely to create unexpected holes in the heat sink 3. Furthermore, even if the heat sink 3 thermally expands, irregular expansion is reduced, and air gaps are less likely to occur even when there is a slight shortage of adhesive 5 between the heat sink 3 and the heat spreader 12. This increases the likelihood that high vertical thermal conductivity will be maintained even when deformation due to heat begins.

[0011] Furthermore, by arranging the diamonds so that the end of the diamond on the other side of the diamond-containing metal layer, or the end of the diamond on the other side of the diamond-containing metal layer before smoothing, forms a vertex or ridgeline (hereinafter, "vertex or ridgeline" may be referred to as "edge portion"). This makes it easier to bring adjacent diamonds into surface contact regardless of the shape or alignment of the diamonds, increasing the degree of freedom in the shape of the diamonds used and 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" refers to the point that three or more sides (ridgelines) of diamond share, and "ridgeline" refers to the line that connects the vertices of diamond.In addition, in this application, "end" refers to the part that is furthest from the center in the thickness direction.For example, "end of one face side of diamond-containing metal layer" refers to the part that is furthest from the center in the diamond in the thickness direction of diamond-containing metal layer in the direction of one face of diamond-containing metal layer, and when the vertex of diamond is the part that is furthest from the center in the direction of one face of diamond-containing metal layer, the end of one face side of diamond-containing metal layer of diamond is vertex, when the ridgeline of diamond is the part that is furthest from the center in the direction of one face of diamond-containing metal layer, the end of one face side of diamond-containing metal layer of diamond is ridgeline, and when the face of diamond is the part that is furthest from the center in the direction of one face of diamond-containing metal layer, the end of one face 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 away 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 away 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 away 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, the proportion of the exposed area of ​​the diamond on one surface of the diamond-containing metal layer is preferably 30% or more. Increasing the exposed area of ​​diamond increases the efficiency of heat inflow to or outflow from the diamond-containing metal layer, thereby improving thermal conductivity. Furthermore, since it is possible to increase the amount of diamond exposed on a face rather than on a vertex or ridge (i.e., a point or line), heat can be efficiently transferred to one face of the diamond-containing metal layer and the adjacent portion.

[0014] In order to further enhance the thermal conductivity, it is preferable that the thermal conductor of the present invention satisfies the above (I), (II) and (III-2), and that the proportion of the exposed area of ​​the diamond on the other surface of the diamond-containing metal layer is 30% or more. By increasing the exposed diamond area 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 form of a truncated octahedron with some of the vertices or ridgelines cut off, or a hexagonal octahedron with some of the vertices or ridgelines cut off, and the diamond (i) has one cut-off surface that is flush with one surface of the diamond-containing metal layer, or (ii) has two cut-off 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. This structure can be achieved by arranging truncated octahedron or hexahedron diamonds in a single layer and smoothing at least one face of the diamond-containing metal layer. Using truncated octahedron or hexahedron diamonds allows for a higher density of diamonds, further increasing the heat flow path 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. This structure makes it difficult for other components to be damaged when joined to them. Furthermore, by combining it with a thermally conductive member, the degree of freedom in designing the shape of the thermal 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. This configuration prevents the diamonds in the heat spreader from deforming the heat source and heat sink, and also allows the heat that flows from the heat source into the heat spreader to be efficiently transferred from the heat spreader to the heat sink, resulting in a heat dissipation structure with excellent heat dissipation properties. [Effects of the Invention]

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

[0020] [Figure 1] 1 is a schematic diagram of a thermal conductor according to an embodiment of the present invention. [Figure 2] 2A to 2C are diagrams for explaining a method for manufacturing the thermal conductor of FIG. 1. [Figure 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. [Figure 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. 10 is a schematic diagram of a heat dissipation structure according to another embodiment of the present invention. [Figure 10] 10A and 10B are diagrams for explaining how a heat sink and a heat spreader of the present invention are joined together. [Figure 11] 10A and 10B are diagrams for explaining how a heat sink and a conventional heat spreader are joined together. DETAILED DESCRIPTION OF THE INVENTION

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

[0022] <Embodiment 1> Figure 1 is a schematic diagram of a thermal conductor 100 according to the present invention. The thermal conductor 100 shown in Figure 1 is a plate-like body made of a diamond-containing metal layer 20 containing a plurality of diamonds 40 arranged in a single layer and a metal 42 that fixes 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 found, for example, by photographing the surface 20S of the diamond-containing metal layer 20 with a microscope such as a digital microscope and then 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 the 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 shown in Figure 2, the diamond-containing metal layer 20 is formed by smoothing the upper surface 21S of a layer 21 in which a plurality of truncated octahedron-shaped diamonds 40b are arranged in a single layer with their vertices or ridges (edges) facing downward (towards the substrate 44), as will be described later. The diamonds 40b are fixed with a metal 42, and the upper surface 21S is smoothed by polishing or other processing. By polishing or other processing, the irregularities on the surface 21S are perfectly smoothed. By arranging the diamonds 40b so that their hexagonal faces are in surface contact with each other, the lateral contact area can be increased.

[0026] In the diamond-containing metal layer 20, the diamond 40 has a shape in which a part of the vertex or ridge of a truncated octahedron has been cut off. Specifically, as shown in Fig. 2, the structure is such that the upper side of a row of truncated octahedron diamonds arranged in a single layer on a substrate 44 with the edge portion facing downward 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, and this face of the cut-off part 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. In this case, 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, it is sufficient that the majority of the multiple diamonds 40 have end portions 40B that are edge portions E, and some diamonds may have end portions 40B that are planes. The proportion of diamonds 40 whose end portions 40B are edge portions E and that are in face-to-face 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 diamond end portions 40B and the presence or absence of face-to-face 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 diamonds 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 comprising 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, after smoothing the surface of the plating layer, the substrate and the diamond-containing metal layer are separated to obtain the thermal conductor.

[0029] The method for manufacturing the thermal conductor 100 will be described in detail with reference to Fig. 2. First, diamonds 40b (diamonds before polishing or other processing) are filled onto a substrate 44 while being vibrated, and the diamonds 40b are arranged at high density with their edges E facing downwards and in face-to-face contact with adjacent diamonds 40b (Fig. 2(A)). Materials that can be used for the substrate 44 include metals such as stainless steel, copper, aluminum, steel, cemented carbide, molybdenum, molybdenum alloy, cermet, and titanium, as well as ceramics and plastics.

[0030] The diamonds 40b (diamonds before polishing or other processing) are preferably selected from those with an average particle size of 35 μm to 1000 μm. Furthermore, the proportion of diamonds 40b with particle sizes within ±15% of the average particle size is preferably 90% or more, more preferably 93% or more, and even more preferably 95% or more. By using diamonds 40b with uniform particle sizes, it is easy to form a structure in which diamonds 40b are arranged at a higher density with the edge portions E of the diamonds 40 facing the substrate 44. This average particle size is the average value of the particle sizes of 100 diamonds 40b, and the particle size of each diamond 40b is the average value of the long and short sides of the circumscribing rectangle. When calculating this average particle size, the proportion of diamonds 40b with particle sizes within ±15% of the average particle size can also be determined.

[0031] Next, metal 42 is deposited on substrate 44 by plating, thereby adhering diamond 40b with metal 42, and plating layer 21 (diamond-containing metal layer before processing such as polishing) is formed on substrate 44 (FIG. 2(B)). Preferred metal 42 is nickel or its alloy, and examples thereof include Ni, Ni-S alloy, Ni-P alloy, Ni-B alloy, and Ni-Co alloy.

[0032] 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 particle size of the diamonds 40b.

[0033] Next, the surface (face 21S) of plating layer 21 formed on substrate 44 is smoothed by processing such as polishing to form diamond-containing metal layer 20 (FIG. 2(C)). Processing such as polishing is carried out until diamonds 40 do not protrude and the exposed area of ​​diamonds 40 on the surface (face 20S) of diamond-containing metal layer 20 to be formed 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 has been 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 joined to another member, it is unlikely to deform the other member.

[0035] Furthermore, as will be described later, 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 that is arranged on one side of the diamond-containing metal layer is flush with 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> Figure 3 is a schematic diagram of a thermal conductor 110 according to the present invention. The thermal conductor 110 shown in Figure 3 is a plate-like body made of a diamond-containing metal layer 22 containing a plurality of diamonds 46 arranged in a single 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 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 proportion of the exposed area of ​​the diamond 46 on the surface 22S is 30% or more (for example, 30% or more and less than 100%). Also, the other surface 22B of the diamond-containing metal layer 22 is 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 proportion of the exposed area of ​​the diamond 46 on the surface 22B is 30% or more (for example, 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 polishing or other processing so that the proportion of the exposed area of ​​the diamonds 46 on the surface 22B is 30% or more. That is, a plurality of truncated octahedron-shaped diamonds 40b arranged in a single layer with their edges E facing downwards are fixed by metal 42, and both surfaces of the layer are smoothed by polishing or other processing. 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. Whether the diamond 46 has been smoothed or not can be determined from the traces of polishing or other processing on the smoothed surface and the shape of the diamond after smoothing. Furthermore, the shape of the end of the diamond before smoothing can be determined from the shape of the diamond after smoothing. Specifically, if the intersection point of the extended ridgeline that contacts the other surface of the smoothed diamond is on the other surface before smoothing, the end of the diamond on the other surface before smoothing can be estimated to be a vertex or a ridgeline.

[0040] In the diamond-containing metal layer 22, the diamonds 46 have a shape in which part of the vertices or ridges of a truncated octahedron have been cut off. Specifically, the diamonds 46 have a structure in which the upper and lower sides of a row of truncated octahedron diamonds arranged in a single layer with the edges facing downwards are cut off by opposing parallel faces, and the diamonds 46 have two cut-off faces, one of which is an end 46S and is flush with face 22S of the diamond-containing metal layer 22, and the other is an end 46B and is flush with face 22B of the diamond-containing metal layer 22.

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

[0042] <Embodiment 3> Figure 4 is a schematic diagram of a thermal conductor 120 according to the present invention. The thermal conductor 120 shown in Figure 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 the surface 20S is located on the side opposite to the flat surface 50X.

[0043] The heat conductive member 50 is a member made of a thermally conductive material 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-like 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 with one side open (see FIG. 6 ). When the heat conductive member is a box-shaped frame, the diamond-containing metal layer may be provided on the side of the flat portion opposite the heat source side, or on the side of the flat portion facing the heat source.

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

[0045] (Production Example 3-1) As a method using a thermally conductive adhesive, for example, a method can be mentioned in which diamond-containing metal layer 20 is obtained in the same manner as in Production Example 1, and then flat portion 50X of thermally conductive member 50 and surface 20B (surface on the substrate 44 side) of diamond-containing metal layer 20 are superimposed and bonded together via a thermally conductive adhesive.

[0046] (Production Example 3-2) A method for directly forming the diamond-containing metal layer 20 on the flat surface 50X of the heat conductive member 50 includes, for example, using the heat conductive member 50 as the substrate 44 and carrying out the filling and plating process of diamond 40 in Production Example 1.

[0047] Furthermore, in the thermal 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 side opposite to the flat surface 50X of the thermal conductive member 50, but this is not limited to this. The thermal conductor of the present invention may also be configured so that the surface 20S of the diamond-containing metal layer 20 is located on the flat surface 50X side of the thermal conductive member 50. A thermal conductor of this structure can be obtained by bonding the flat surface 50X and the surface 20S of the diamond-containing metal layer 20 with an adhesive, instead of bonding the flat surface 50X and the surface 20B of the diamond-containing metal layer 20 with an adhesive in Production Example 3-1. Furthermore, in the thermal 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 thermally 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 thermally 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. The diamond-containing metal layers 23 and 24 are both arranged so that the surfaces 23S and 24S corresponding to the surface 20S of the diamond-containing metal layer 20 are located on the opposite side to the flat surface 50X, and multiple diamonds 40 are arranged in a single layer with their edges facing the flat surface 50X. The diamond-containing metal layers 23 and 24 are also bonded to the thermally conductive member 50 and thermally connected.

[0049] The method for joining diamond-containing metal layer 23 and heat conductive member 50 may be the same as or different from the method for joining diamond-containing metal layer 24 and heat conductive member 50. 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 surface 23S and surface 24S, and these manufacturing methods may also be combined.

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

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

[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 have one smoothed surface facing the flat surface of the heat conductive member, or facing the opposite side to the flat surface. Furthermore, in the heat conductors 130 and 140, one or both of the diamond-containing metal layers may be configured as 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 component including a base 30 having a surface 30S facing the heat source 1, and is exemplified by a component including 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 component 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, heat from the heat source 1 can be conducted from the heat spreader 10 to the heat sink 3 and dissipated from the heat sink 3 to the outside.

[0055] For example, the heat dissipation structure 200 can be configured as a heat dissipation structure 200a shown in Figure 8(A), in which the heat spreader 10 is a diamond-containing metal layer 20 (thermal conductor 100) and is bonded to a heat source 1 with an adhesive 5 (thermally conductive adhesive), and a heat sink 3 bonded to the heat spreader 10 with the adhesive 5.

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

[0057] 8(C) and 8(D), the heat dissipation structure 200 may have a configuration in which a diamond-containing metal layer of the thermal conductor of the present invention is formed directly 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 with 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 with an adhesive 5, and a diamond-containing metal layer 20 formed directly on the heat conductive member 50. The diamond-containing metal layer 20 formed directly on the heat conductive member 50 is bonded to the heat source 1 with 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 forms the heat spreader 10. The heat dissipation structure 200d can be obtained by the following method. First, using the heat sink 3 as the substrate 44, diamonds are arranged with their edges facing the surface 30S of the heat sink 3, plated, and then smoothed to form the diamond-containing metal layer 20. Separately, diamonds are arranged with their edges facing one side of the flat surface 50X of the heat conductive member 50, plated, and then 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 bonded together 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-conducting member 52. The diamond-containing metal layer 27 includes a plurality of diamonds 48 arranged in a single layer and a metal 42 that secures the diamonds 48. The diamonds 48 are polyhedrons with an octahedron or higher order, do not protrude from the diamond-containing metal layer 27, and are in surface contact with adjacent diamonds 48. One surface 27S of the diamond-containing metal layer 27 is smoothed so 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 (the copper plate 70 side) of the diamond-containing metal layer 27 is an apex or a ridge. Copper plate 70 having diamond-containing metal layer 27 formed thereon is bonded to both sides of flat surface portion 52X of thermally conductive member 52 via thermally conductive adhesive 5. Heat sink 3 is bonded to diamond-containing metal layer 27 located outside flat surface portion 52X of thermally conductive member 52 with adhesive 5.

[0062] When used as a heat dissipation structure for a CPU die 1a, the heat dissipation structure 210 is placed on a 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 an 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, for example, used in heat sinks, heat spreaders, etc., and is therefore industrially useful. [Explanation of symbols]

[0064] 1 Heat source 1a CPU die 3 Heatsink 3H hole 4a, 4b, 40, 40b, 46, 48 Diamond 5. Adhesive 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 End 42 metal 44 PCB 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 octahedron 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 the one surface 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 ridge of the diamond. (III-2) The other surface of the diamond-containing metal layer is a surface that 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 a vertex or a ridge line.

2. 2. The heat conductor according to claim 1, wherein the diamond-containing metal layer is formed by fixing a plurality of diamonds, each of which is an octahedron or larger polyhedron, arranged in a single layer with its vertices or edges facing downwards, with the diamond-containing metal layer having at least the upper surface smoothed.

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

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

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

6. a thermally conductive member having a flat portion; the diamond-containing metal layer disposed on at least one side of the flat surface portion, 2. The heat conductor according to claim 1, wherein the diamond-containing metal layer is disposed so 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 bonded to the heat spreader.

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