Heat dissipation member and electronic device

Abstract

The heat dissipation member according to the present invention includes a copper-diamond composite in which a plurality of diamond particles are dispersed in a metal matrix containing copper, and a metal film bonded to at least one surface of the copper-diamond composite, the copper-diamond composite having a coarse particle layer and a fine particle layer in at least one of cross sections in the lamination direction of the heat dissipation member, the coarse grain layer contains the diamond particles having coarse grains having a large grain diameter, the fine particle layer contains diamond particles having fine particles having a smaller grain diameter than the coarse grains, and the copper-diamond composite has a structure in which the fine particle layer is disposed on the bonding surface side of the copper-diamond composite and the metal film with respect to the coarse grain layer.

Description

Technical Field

[0001] The invention relates to a heat dissipation component and an electronic device. Background Art

[0002] Various heat dissipation components using copper-diamond composites have been developed so far. As such a technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes a composite material of a metal matrix-heat conductor particles. Since such a composite material contains ceramic particles such as diamond particles and SiC particles, it is difficult to grind the surface of the composite material and process it to be flat (Paragraph 0012).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2016 / 035796 Summary of the invention

[0006] However, as a result of studies by the present inventors, it has been found that the heat dissipation component described in Patent Document 1 has room for improvement in thermal conductivity.

[0007] The present inventors have further studied and found that the thermal conductivity of the heat dissipation component can be improved by forming a fine particle layer including fine diamond particles on the bonding surface side of a copper-diamond composite bonded to a metal film on at least one surface thereof, thereby completing the present invention.

[0008] According to one embodiment of the present invention, the following heat dissipation component and electronic device are provided.

[0009] 1. A heat dissipation component, comprising:

[0010] A copper-diamond composite having a plurality of diamond particles dispersed in a metal matrix containing copper, and

[0011] a metal film bonded to at least one surface of the copper-diamond composite,

[0012] In at least one of the cross sections of the heat sink in the stacking direction, the copper-diamond composite has a coarse-grained layer and a fine-grained layer.

[0013] The coarse-grained layer contains the above-mentioned coarse-grained diamond particles having a large particle size.

[0014] The fine particle layer includes the diamond particles having a particle size smaller than that of the coarse particles.

[0015] Furthermore, the copper-diamond composite has a structure in which the fine particle layer is arranged on the bonding surface side of the copper-diamond composite and the metal film relative to the coarse particle layer.

[0016] 2. The heat dissipation component according to item 1, wherein:

[0017] When the particle size distribution of the diamond particles is measured using an imaging particle size distribution measuring device, in the volume particle size distribution of the particle diameter of the diamond particles,

[0018] The particle size D at which the cumulative value of the above coarse particles is 50% 50 Greater than 100 μm and less than 300 μm,

[0019] The particle size D at which the cumulative value of the above particles is 50% 50 Less than 100 μm.

[0020] 3. The heat dissipation component according to 1 or 2, wherein:

[0021] The copper-diamond composite has a stacked structure including a first fine particle layer and a coarse particle layer in this order in the layer thickness direction, or a stacked structure including a first fine particle layer, a coarse particle layer, and a second fine particle layer in this order in the layer thickness direction.

[0022] 4. The heat dissipation component according to 3, wherein:

[0023] The thickness of the particle layer is 3 μm to 200 μm.

[0024] 5. The heat dissipation component according to any one of 1 to 4, wherein

[0025] The flatness of the bonding surface between the copper-diamond composite and the metal film is 30 μm or less.

[0026] 6. The heat dissipation component according to any one of 1 to 5, wherein

[0027] A ten-point average height Rz of a bonding surface between the copper-diamond composite and the metal film is 20 μm or less.

[0028] 7. The heat dissipation component according to any one of 1 to 6, wherein

[0029] The thermal conductivity of the copper-diamond composite is 600 W / m·K or more.

[0030] 8. The heat dissipation component according to any one of 1 to 7, wherein

[0031] When the particle size distribution of the diamond particles is measured using an imaging particle size distribution measuring device, in the volume particle size distribution of the sphericity of the diamond particles,

[0032] The cumulative value of the above coarse particles is 50% of the sphericity D 50 It is above 0.8.

[0033] 9. An electronic device comprising:

[0034] The heat dissipation component according to any one of 1 to 8, and

[0035] The electronic component is arranged on the heat dissipation component.

[0036] According to the present invention, there are provided a heat dissipation component having excellent thermal conductivity and an electronic device using the heat dissipation component. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic cross-sectional view showing an example of the structure of the heat dissipation member according to the present embodiment. DETAILED DESCRIPTION

[0038] Hereinafter, the embodiments of the present invention will be described using the accompanying drawings. It should be noted that in all the drawings, the same components are marked with the same symbols, and the description is appropriately omitted. In addition, the drawings are schematic diagrams and do not correspond to the actual size ratios.

[0039] use Figure 1 The outline of the heat dissipation member according to the present embodiment will be described.

[0040] Figure 1 It is a schematic cross-sectional view showing an example of the structure of the heat dissipation member according to the present embodiment.

[0041] The heat dissipation component 100 of the present embodiment includes a copper-diamond composite 30 in which a plurality of diamond particles 20, 22 are dispersed in a metal matrix 10 containing copper, and a metal film 50 bonded to at least one surface of the copper-diamond composite 30. In at least one of the cross sections in the stacking direction of the heat dissipation component 100, the copper-diamond composite 30 has a coarse-grained layer 32 and a fine-particle layer 34. The coarse-grained layer 32 includes coarse-grained diamond particles 20 having a large particle size, and the fine-particle layer 34 includes fine-particle diamond particles 22 having a smaller particle size than the coarse particles. The fine-particle layer 34 has a structure in which the fine-particle layer 34 is arranged on the bonding surface (bonding interface 12) side of the copper-diamond composite 30 and the metal film 50 relative to the coarse-grained layer 32.

[0042] According to the findings of the present inventors, by using the microparticle layer 34 including microparticle diamond particles 22, the smoothness of the surface of the copper-diamond composite 30 (hereinafter also referred to as the "composite") can be improved, thereby reducing the thickness of the metal film 50 formed on the surface and / or improving the adhesion with the metal film 50, and as a result, the thermal conductivity of the heat dissipation component 100 including the composite and the metal film 50 can be improved.

[0043] The detailed mechanism is still uncertain, but it is believed that if the thickness of the metal film 50 is increased, the inherent high thermal conductivity of the composite is reduced. However, by appropriately smoothing the surface of the composite, the thickness of the metal film 50 required to fill the large surface irregularities can be reduced, and the adhesion between the composite and the metal film 50 can be improved, which can suppress the reduction in the overall thermal conductivity of the heat dissipation component 100 composed of the copper-diamond composite 30 and the metal film 50.

[0044] In addition, according to the present embodiment, a coarse-grained layer 32 including coarse-grained diamond particles 20 is disposed in the inner layer of the composite. Compared with fine-grained diamond particles, the coarse-grained diamond particles 20 in the coarse-grained layer 32 can effectively exhibit the inherent thermal conductivity of diamond because (i) aggregation is suppressed, (ii) pores are formed due to poor adhesion around the copper-diamond interface, or (iii) the increase of grain boundaries is suppressed to reduce the thermal conductivity, etc. Therefore, by providing the fine-grained layer 34 and the coarse-grained layer 32, the thermal conductivity can be further improved.

[0045] The lower limit of the thermal conductivity of the heat dissipating member 100 is preferably 600 W / m·K or more, more preferably 630 W / m·K or more, and further preferably 650 W / m·K or more. This improves the heat dissipation characteristics of the heat dissipating member.

[0046] On the other hand, the upper limit of the thermal conductivity of the heat dissipating member 100 is not particularly limited, but is preferably 950 W / m·K or less, more preferably 900 W / m·K or less, and further preferably 870 W / m·K or less.

[0047] The configuration of the heat dissipation member of this embodiment will be described in detail.

[0048] The heat dissipation member 100 includes a copper-diamond composite 30 and a metal film 50 .

[0049] (Copper-Diamond Composite)

[0050] The copper-diamond composite 30 includes a metal matrix 10 containing copper and a plurality of diamond particles 20 , 22 present in the metal matrix 10 .

[0051] The lower limit of the thermal conductivity of the copper-diamond composite 30 is preferably 600 W / m·K or more, more preferably 630 W / m·K or more, and even more preferably 650 W / m·K or more. This improves the heat dissipation characteristics of the heat dissipation component.

[0052] On the other hand, the upper limit of the thermal conductivity of the copper-diamond composite 30 is not particularly limited, but is preferably 950 W / m·K or less, more preferably 900 W / m·K or less, and further preferably 870 W / m·K or less.

[0053] The shape and size of the copper-diamond composite 30 can be appropriately set according to the application.

[0054] Examples of the shape of the copper-diamond composite 30 include a flat plate shape, a block shape, and a rod shape.

[0055] The metal base 10 only needs to contain copper, and may contain other high thermal conductivity metals other than copper. That is, the metal base 10 is composed of a copper phase and / or a copper alloy phase.

[0056] From the viewpoint of thermal conductivity and cost, the main component of the metal base 10 is preferably copper.

[0057] The lower limit of the content of the main component copper is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more in 100% by mass of the metal substrate 10. Thus, the good thermal conductivity of copper and copper alloys can be utilized, and in order to ensure solderability and surface smoothness, the same copper as the substrate can be used as the surface layer, and the formation of other surface coating layers can be omitted.

[0058] The upper limit of the content of copper as the main component is not particularly limited in 100 mass % of the metal base 10 , but may be 100 mass % or less, or 99 mass % or less.

[0059] As other high thermal conductivity metals, for example, silver, gold, aluminum, etc. can be cited. These can be used alone or in combination of two or more. When copper is combined with other high thermal conductivity metals, alloys or composite materials formed of copper and other high thermal conductivity metals can be used.

[0060] It should be noted that the metal base 10 may be made of metals other than high thermal conductivity metals, as long as the effects of the present invention are not impaired.

[0061] When a copper alloy is used as the metal base 10 , examples of the copper alloy include CuAg, CuAl, CuSn, CuZr, and CrCu.

[0062] The metal base 10 is, for example, a sintered body of metal powder containing copper (and other optically and thermally conductive metals as needed). In the present embodiment, the metal base 10 is composed of a sintered body in which at least a part of the plurality of diamond particles 20 and 22 are embedded.

[0063] The copper-diamond composite 30 has at least a coarse-grained layer 32 and a fine-grained layer 34 (first fine-grained layer).

[0064] In the heat dissipation component 100 of the present embodiment, a fine particle layer 34 including fine diamond particles 22 is arranged on the surface (joining interface 12) side of the copper-diamond composite 30. Compared with the case where a coarse particle layer 32 including coarse diamond particles 20 is formed on the surface, the fine particle layer 34 can reduce the surface roughness of the surface of the composite, that is, can smooth the surface of the composite.

[0065] An example of the copper-diamond composite 30 may be a laminated structure having a first particle layer (particle layer 34) and a coarse particle layer 32 in the layer thickness direction, or may be a laminated structure having a first particle layer (particle layer 34), a coarse particle layer 32, and a second particle layer (particle layer 36) in the layer thickness direction. That is, the copper-diamond composite 30 may be composed of a sintered body having at least a two-layer structure or a three-layer structure. Thus, the thermal conductivity in the thickness direction can be further improved.

[0066] The sphericity and particle size of the diamond particles 20 and 22 were measured in the following manner.

[0067] The particle size distribution of the diamond particles 20 and 22 is measured using an imaging particle size distribution measuring device (for example, Morphologi 4 manufactured by Malvern). The particle size distribution includes shape distribution and particle diameter distribution.

[0068] Based on the obtained particle size distribution, the volume particle size distribution of sphericity and the volume particle size distribution of particle diameter were prepared.

[0069] Then, in the volume particle size distribution of the sphericity of the diamond particles 20 , a predetermined cumulative value of the sphericity and a predetermined cumulative value of the particle size are obtained.

[0070] Here, sphericity and particle size are defined as follows.

[0071] Sphericity: The ratio of the circumference of a circle with the same area as the projected object to the circumference of the object. Particle size: The maximum length between two points on the contour of the particle image.

[0072] The particle size D at which the cumulative value of the coarse diamond particles 20 measured in the above-mentioned steps is 50% 50 The upper limit is, for example, 300 μm or less, preferably 270 μm or less, more preferably 250 μm or less, further preferably 220 μm or less, particularly preferably 200 μm or less, and most preferably 180 μm or less. Thus, the filling degree of the diamond particles 20 can be increased, and the thermal conductivity of the composite can be increased.

[0073] The particle size D of the coarse diamond particles 20 is 50 The lower limit exceeds 100 μm.

[0074] The cumulative value of the coarse diamond particles 20 measured in the above steps is 50% of the sphericity S 50 The lower limit of is, for example, 0.8 or more, preferably 0.85 or more, more preferably 0.87 or more, and further preferably 0.9 or more. This can increase the filling degree of the diamond particles 20 and improve the thermal conductivity of the composite.

[0075] On the other hand, the sphericity S of the coarse diamond particles 20 is 50 The upper limit of is not particularly limited, and may be, for example, 1.0 to 0.99.

[0076] The particle size D at which the cumulative value of the fine-particle diamond particles 22 measured in the above-mentioned steps is 50% 50 The upper limit of is, for example, 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less, and further preferably 10 μm or less. This can improve the surface smoothness of the composite and improve the thermal conductivity of the heat dissipating member 100 .

[0077] The particle size D of the diamond particles 22 is 50 The lower limit of is not particularly limited, and may exceed 0.1 μm, for example.

[0078] In the coarse-grained layer 32, one diamond particle 20 may have a connection structure in which it contacts other diamond particles 20. In the connection structure, at least one, two or four diamond particles 20 may be in continuous contact with each other. Thus, the thermal conductivity of the heat dissipation component 100 can be improved.

[0079] It should be noted that the above-described connection structure is confirmed in at least one of the cross sections in the thickness direction of the heat dissipation member 100 .

[0080] The upper limit of the thickness of the fine particle layer 34 and / or the fine particle layer 36 is, for example, 200 μm or less, preferably 150 μm or less, and more preferably 100 μm or less. This can suppress a decrease in the thermal conductivity of the heat dissipating member 100 .

[0081] On the other hand, the lower limit of the thickness of the fine particle layer 34 and / or the fine particle layer 36 is, for example, 3 μm or more, preferably 5 μm or more, and more preferably 8 μm or more. This can improve the surface smoothness of the composite.

[0082] The upper limit of the flatness of the bonding surface (bonding interface 12 ) between the copper-diamond composite 30 and the metal film 50 is, for example, 30 μm or less, preferably 20 μm or less, and more preferably 10 μm or less. This can improve the thermal conductivity of the heat dissipating member 100 .

[0083] On the other hand, the lower limit of the flatness is not particularly limited, but may be 1 μm or more.

[0084] The flatness can be calculated using a digital microscope in accordance with JIS B 0621:1984.

[0085] The upper limit of the ten-point average height Rz of the bonding surface (bonding interface 12 ) between the copper-diamond composite 30 and the metal film 50 is, for example, 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. This can improve the thermal conductivity of the heat dissipating member 100 .

[0086] On the other hand, the lower limit of the ten-point average height Rz is not particularly limited, and may be, for example, 0.1 μm or more, 0.5 μm or more, or 1 μm or more.

[0087] The ten-point average height Rz can be calculated in accordance with JIS B 0601:2013.

[0088] A transition region where both diamond particles 20 and diamond particles 22 exist can be formed between fine particle layer 34 and coarse particle layer 32 and / or between fine particle layer 36 and coarse particle layer 32. This can suppress a decrease in the inherent thermal conductivity of diamond in the composite.

[0089] The transition region can be confirmed by a cross-sectional SEM image of the heat dissipation member 100 in the thickness direction.

[0090] The diamond particles 20 and 22 include at least one of uncoated diamond particles having no metal-containing coating layer on the surface and coated diamond particles having a metal-containing coating layer on the surface. Coated diamond particles are more preferred from the viewpoint of improving the adhesion and dispersibility between diamond and metal particles.

[0091] The lower limit of the total volume ratio of diamond particles 20 and diamond particles 22 in the copper-diamond composite 30 is preferably 10 volume % or more, more preferably 20 volume % or more, and further preferably 30 volume % or more. This can improve the thermal conductivity of the copper-diamond composite 30.

[0092] On the other hand, the upper limit of the total volume ratio of the diamond particles 20 and the diamond particles 22 in the copper-diamond composite 30 is, for example, preferably 80 volume % or less, more preferably 70 volume % or less, and further preferably 60 volume % or less. Thus, in the copper-diamond composite 30, it is possible to suppress large pores from remaining around the diamond particles 20 due to the decrease in the surrounding adhesion of the copper powder, and to realize a structure with excellent manufacturing stability.

[0093] When using coated diamond particles as diamond particles 20, the metal-containing coating in the coated diamond particles can contain molybdenum, tungsten, chromium, zirconium, hafnium, vanadium, niobium, tantalum and their alloys etc. These can be used alone or in combination of two or more. In addition, the metal-containing coating is formed in a manner covering at least a portion of the particle surface or the entire surface.

[0094] (metal film)

[0095] The metal film 50 may be formed on at least one surface of the copper-diamond composite 30 , and may be formed on both surfaces of the flat copper-diamond composite 30 , for example.

[0096] The metal film 50 may contain one or more selected from copper, silver, gold, aluminum, nickel, zinc, tin and magnesium. Preferably, the metal film 50 contains the same metal as the main component metal in the metal substrate 10, preferably at least copper or a copper alloy.

[0097] The content of copper as the main component is preferably 50 mass % or more, more preferably 60 mass % or more, further preferably 70 mass % or more, particularly preferably 80 mass % or more, and most preferably 90 mass % or more in 100 mass % of the metal film 50 .

[0098] The upper limit of the content of copper as the main component is not particularly limited in 100 mass % of the metal film 50 , but may be 100 mass % or less, or 99 mass % or less.

[0099] The upper limit of the film thickness of the metal film 50 is preferably 150 μm or less, more preferably 120 μm or less, and further preferably 100 μm or less. This can increase the thermal conductivity of the heat dissipation component.

[0100] On the other hand, the lower limit of the film thickness of the metal film 50 is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. This can improve the adhesion strength with the composite and the durability of the metal film 50 itself.

[0101] The metal film 50 can be obtained by, for example, a sputtering method or a plating method.

[0102] The average crystal grain size of the metal in the metal film 50 is preferably 5 nm to 50 nm, more preferably 10 nm to 40 nm, and further preferably 20 nm to 30 nm. The average crystal grain size can be obtained from the structure obtained by transmission electron microscopy (TEM) from 1 μm to 2 μm. 2 It is calculated based on the number of grains inside.

[0103] The electronic device according to the present embodiment includes the above-mentioned heat dissipation component and an electronic component provided on the heat dissipation component.

[0104] Examples of electronic components include semiconductor elements, etc. Specific examples of semiconductor elements include power semiconductors, image display elements, microprocessor units, laser diodes, and the like.

[0105] Heat dissipation components are used for heat sinks, heat sinks, etc. The heat sink dissipates the heat generated by the semiconductor element when it is working to the external space, and the heat sink transfers the heat generated by the semiconductor element to other components.

[0106] The electronic component may be provided on the heat dissipation component directly or indirectly via a ceramic substrate or the like.

[0107] An example of a method for manufacturing a heat dissipating member according to the present embodiment will be described.

[0108] An example of a method for producing a heat dissipating component includes a raw material mixing step, a sintering step, and a film forming step.

[0109] In the raw material mixing step, a copper-diamond mixture A including copper-containing metal powder and coarse diamond particles 20 and a copper-diamond mixture B including copper-containing metal powder and fine diamond particles 22 are prepared. The mixing of these mixtures can be carried out by various methods such as dry and wet methods.

[0110] In one example of producing the copper-diamond mixture A, a metal powder containing copper, such as copper powder, and coarse diamond particles 20 are dry-mixed to obtain the copper-diamond mixture A in powder form.

[0111] In one example of producing the copper-diamond mixture B, a metal powder containing copper such as copper powder and fine-particle diamond particles 22 are dry-mixed to obtain a powdery copper-diamond mixture B.

[0112] In one example of preparing the copper-diamond mixture B, a metal powder containing copper such as copper powder and fine-particle diamond particles 22 are wet-mixed in a solvent to obtain a copper-diamond paste (sometimes simply referred to as a paste).

[0113] A known method can be used for mixing during the preparation of the paste, and for example, a mixing method using a roller can be adopted.

[0114] The solvent is not particularly limited as long as it can disperse the metal powder and diamond particles 22. Alcohol solvents such as terpineol, ethylene glycol, glycerin, and Texanol (ester alcohol 12), glycol ether solvents such as butyl carbitol, glycol ester solvents such as butyl carbitol acetate, ketone solvents such as methyl ethyl ketone and isophorone, etc. can be used.

[0115] The copper-diamond paste may contain additives such as a binder resin as necessary. Examples of the binder resin include amino resins, ketone resins, ethyl cellulose, and nitro cellulose.

[0116] The viscosity of the copper-diamond paste is measured at 25° C. using a B-type viscometer and is, for example, 10 Pa·s to 1000 Pa·s, preferably 30 Pa·s to 500 Pa·s, and more preferably 50 Pa·s to 300 Pa·s.

[0117] The metal powder may include copper powder and / or copper alloy powder.

[0118] Average particle size of metal powder D 50 For example, the thickness may be 0.1 μm to 3 μm, 0.2 μm to 2 μm, or 3 μm to 1 μm.

[0119] In this specification, unless otherwise specified, "to" means that the upper limit and the lower limit are included.

[0120] In the calcination step, the copper-diamond mixture A including the coarse-grained diamond particles 20 and the copper-diamond film including the fine-grained diamond particles 22 are stacked and calcined to obtain a composite sintered body (copper-diamond composite 30) having at least a two-layer structure. The copper-diamond film is a dry film formed by applying the obtained copper-diamond paste on a copper plate and drying it.

[0121] When the copper and diamond powder mixture is prepared by dry mixing, the copper-diamond mixture B can be filled on the upper and lower surfaces of the copper and coarse diamond mixed layer to form a three-layer structure to obtain a sintered body.

[0122] In one example of the calcination process, the copper-diamond mixture may be calcined by sandwiching both sides of the copper-diamond mixture with copper-diamond films to obtain a sintered body with a three-layer structure.

[0123] The calcination temperature can be appropriately selected according to the type of metal contained in the metal powder, but in the case of copper powder, it is preferably 800°C to 1100°C, and more preferably 850°C to 1000°C. By setting the calcination temperature to 800°C or higher, the copper-diamond composite is densified and the desired thermal conductivity is obtained. By setting the calcination temperature to 1100°C or lower, the degradation caused by graphitization of the interface of the diamond particles can be suppressed, and the reduction of the original thermal conductivity of the diamond can be prevented.

[0124] The calcination time is not particularly limited, but is preferably 5 minutes to 3 hours, and more preferably 10 minutes to 2 hours. By setting the calcination time to more than 5 minutes, the copper-diamond composite is densified and the desired thermal conductivity can be obtained. By setting the calcination time to less than 3 hours, the formation of carbides and film thickening between the diamond in the coated diamond particles and the metal on the coated surface can be suppressed, thereby causing a decrease in thermal conductivity caused by phonon scattering and cracks caused by differences in linear expansion coefficients. In addition, the productivity of the composite can be improved.

[0125] In the calcination step, either normal pressure sintering or pressure sintering may be used, but in order to obtain a dense composite body, pressure sintering is preferred.

[0126] As a pressure sintering method, hot pressing sintering, spark plasma sintering (SPS), hot isostatic pressing (HIP) and the like can be cited. In the case of hot pressing sintering and SPS sintering, the pressure is preferably more than 10MPa, more preferably more than 30MPa. On the other hand, in the case of hot pressing sintering and SPS sintering, the pressure is preferably less than 100MPa. By setting the pressure to more than 10MPa, the copper-diamond composite is densified and the desired thermal conductivity can be obtained. By setting the pressure to less than 100MPa, it is possible to prevent the generation of diamond cracks, the increase of the diamond interface, the decrease in the adhesion between the diamond crushing surface and the metal, and the original thermal conductivity of the diamond is reduced.

[0127] In the film forming step, the metal film 50 is formed on at least a portion of the surface of the copper-diamond composite 30 .

[0128] The metal film can be formed by a general method such as sputtering, plating, or pressure co-firing using copper foil or copper plate. For thinning, sputtering can be used.

[0129] In addition, at least a portion of the surface of the metal film may be surface-grinded or polished, thereby improving the surface smoothness of the metal film after the film-forming step.

[0130] Furthermore, a smoothing step of the composite sintered body may be performed after the calcining step as necessary. In the smoothing step, at least a portion of the surface of the composite sintered body is ground or polished.

[0131] Furthermore, an annealing step of the composite sintered body may be additionally performed between the calcining step and the smoothing step.

[0132] Furthermore, the copper-diamond composite may be subjected to a step of performing a shape processing, a hole forming processing, or the like before the film forming step.

[0133] The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted. In addition, the present invention is not limited to the above-mentioned embodiments, and modifications and improvements within the scope of achieving the purpose of the present invention are included in the present invention.

[0134] Example

[0135] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the description of these Examples.

[0136] <Production of composite bodies and heat dissipation components>

[0137] (Example 1)

[0138] Copper powder (average particle size D 50 : 0.5 μm) and diamond particles A (Mo coating) shown in Table 1, the weighed powders were mixed in terpineol (solvent), and a paste was prepared using three rollers.

[0139] The viscosity of the obtained paste was measured at 25° C. using a B-type viscometer and was 150 Pa·s.

[0140] The obtained paste was applied onto a copper foil and dried at 80° C. for 1 hour to form a dry film. Two sets of the copper foils with the dry films were prepared.

[0141] The thickness of the dried film of the paste on the copper foil was confirmed by a cross-sectional SEM image in the thickness direction and was 15 μm.

[0142] Copper powder (average particle size D 50 : 0.5 μm) and diamond particles B (Mo coating) shown in Table 1, the weighed powders were uniformly mixed in a V-type mixer to obtain a mixture (raw material mixing step).

[0143] Next, the mixture was sandwiched on both sides with copper foil with dry film, the copper foil was peeled off, and the three-layer structure of dry film / mixture / dry film was filled in the calcination mold. The three-layer structure in the calcination mold was heated and sintered at 900°C for 1 hour under a pressure of 30 MPa using an SPS calcination device to obtain a disk-shaped composite three-layer structure sintered body (copper-diamond composite) (sintering process).

[0144] The composite three-layer structure sintered body has an outer diameter of 30 mmφ and a thickness of 3 mm.

[0145] The particle size distribution (shape distribution / particle diameter distribution) of the raw diamond particles A and B was measured using an imaging particle size distribution measuring device (Morphologi 4, manufactured by Malvern).

[0146] In the volume particle size distribution of the sphericity of diamond particles, the sphericity S at which the cumulative value is 50% is calculated. 50 In the volume particle size distribution of diamond particles, find the particle size D at which the cumulative value is 50%. 50 The values ​​were averaged from two determinations.

[0147] Sphericity and particle size are defined as follows.

[0148] Sphericity: The ratio of the circumference of a circle with the same area as the projected object to the circumference of the object. Particle size: The maximum length between two points on the contour of the particle image.

[0149] As a result, the particle size D of the diamond particles A used was 50 The sphericity S of diamond particles B is 5 μm. 50 is 0.9, particle size D 50 is 200μm.

[0150] In the copper-diamond composite, a three-layer structure of a first particle layer formed by fine-grained diamond particles A dispersed in a copper matrix / a coarse-grained layer formed by coarse-grained diamond particles B dispersed in a copper matrix / a second particle layer formed by fine-grained diamond particles A dispersed in a copper matrix was confirmed based on a cross-sectional SEM image in the thickness direction.

[0151] The thickness of the first fine particle layer and the second fine particle layer determined from the cross-sectional SEM image in the thickness direction were 12.3 μm, respectively.

[0152] The surface roughness and flatness of the surface of the first fine particle layer of the copper-diamond composite (the surface region spanning from the copper matrix to the diamond particles A) were observed and measured using a digital microscope (VHX-8000, manufactured by Keyence). The ten-point average height Rz calculated in accordance with JIS B0601:2013 was 2.5 μm, and the flatness calculated in accordance with JIS B 0621:1984 was 5.3 μm.

[0153] The thermal conductivity of the surface of the copper-diamond composite was measured by the laser flash method and the result was 812 W / m·K. The laser flash method was performed at room temperature after a carbon coating was applied to the surface of the sample.

[0154] Then, a Cu film having a thickness of 50 μm was formed on both surfaces of the copper-diamond composite by sputtering to obtain a heat dissipation member consisting of Cu film / copper-diamond composite / Cu film (film forming step).

[0155] The thermal conductivity of the heat dissipation component was measured by the laser flash method and the result was 765 W / m·K.

[0156] (Examples 2 to 4)

[0157] A composite and a heat dissipating member were obtained in the same manner as in Example 1 except that the particle size, sphericity and thickness of the fine particle layer of the diamond particles were changed to the conditions described in Table 1.

[0158] The same evaluation as in Example 1 was performed on the obtained composite and heat dissipating component.

[0159]

[0160] (Example 5)

[0161] Copper powder (average particle size D 50 : 0.5 μm) and diamond particles A (Mo coating) shown in Table 2, the weighed powders were uniformly mixed in a V-type mixer to obtain a mixture A (raw material mixing step 1).

[0162] Copper powder (average particle size D 50 : 0.5 μm) and diamond particles B (Mo coating) shown in Table 2, the weighed powders were uniformly mixed in a V-type mixer to obtain a mixture B (raw material mixing step 2).

[0163] Next, the obtained mixtures A and B were filled into a calcination mold to form a three-layer structure of mixture A / mixture B / mixture A. The three-layer structure in the calcination mold was heated and sintered at 900° C. for 1 hour under a pressure of 30 MPa using an SPS calcination device to obtain a disk-shaped composite three-layer structure sintered body (copper-diamond composite) (sintering step).

[0164] The composite three-layer structure sintered body has an outer diameter of 30 mmφ and a thickness of 3 mm.

[0165] In the copper-diamond composite, a three-layer structure of a first fine particle layer formed by fine-grained diamond particles A dispersed in a copper matrix / a coarse-grained layer formed by coarse-grained diamond particles B dispersed in a copper matrix / a second fine-grained layer formed by fine-grained diamond particles A dispersed in a copper matrix was confirmed based on a cross-sectional SEM image in the thickness direction.

[0166] The thicknesses of the first fine particle layer and the second fine particle layer determined from the cross-sectional SEM image in the thickness direction were 20.7 μm and 21.3 μm, respectively.

[0167] The surface roughness and flatness of the surface of the first fine particle layer of the copper-diamond composite (the surface region spanning from the copper matrix to the diamond particles A) were observed and measured using a digital microscope (VHX-8000, manufactured by Keyence). The ten-point average height Rz calculated in accordance with JIS B0601:2013 was 2.3 μm, and the flatness calculated in accordance with JIS B 0621:1984 was 4.9 μm.

[0168] The thermal conductivity of the surface of the copper-diamond composite was measured by the laser flash method and the result was 801 W / m·K. The laser flash method was performed at room temperature after a carbon coating was applied to the surface of the sample.

[0169] Then, a Cu film having a thickness of 50 μm was formed on both surfaces of the copper-diamond composite by sputtering to obtain a heat dissipation member consisting of Cu film / copper-diamond composite / Cu film (film forming step).

[0170] The thermal conductivity of the heat dissipation component was measured by the laser flash method and the result was 726 W / m·K.

[0171] (Examples 6 to 9)

[0172] A composite and a heat dissipating member were obtained in the same manner as in Example 5 except that the particle size, sphericity and thickness of the fine particle layer of the diamond particles were changed to the conditions described in Table 2.

[0173] The same evaluation as in Example 5 was performed on the obtained composite and heat dissipating component.

[0174]

[0175] (Comparative Example 1)

[0176] A composite and a heat dissipating component were obtained in the same manner as in Example 1 except that the copper foil with a dry film and the three-layer structure of dry film / mixture / dry film were not used and the single-layer structure of the mixture was fired.

[0177] Specifically, copper powder and diamond particles B (Mo coating) shown in Table 3 were weighed at 50 volume %:50 volume %, and the weighed powders were uniformly mixed in a V-type mixer to obtain a mixture.

[0178] Next, the obtained mixture was filled into a mold using an SPS calcining device, and heated and sintered at 900° C. for 1 hour under a pressure of 30 MPa to obtain a composite single-layer sintered body (copper-diamond composite) in which a plurality of diamond particles were dispersed in a copper matrix.

[0179] The composite single-layer sintered body has an outer diameter of 30 mmφ and a thickness of 3 mm.

[0180] Then, a Cu film having a thickness of 30 μm was formed on both surfaces of the copper-diamond composite by sputtering, thereby obtaining a heat dissipation component consisting of Cu film / copper-diamond composite / Cu film.

[0181] The same evaluation as in Example 1 was performed on the obtained composite and heat dissipating component.

[0182] [Table 3]

[0183] Table 3

[0184]

[0185] As shown in Table 1, the heat dissipating components of Examples 1 to 9 showed a result that a superior thermal conductivity was achieved compared to Comparative Example 1.

[0186] This application claims the benefit of priority based on Japanese patent application No. 2022-074853, filed on April 28, 2022, and incorporates all the disclosure thereof into this application.

[0187] Explanation of symbols

[0188] 10Metal substrate

[0189] 12Joint interface

[0190] 20, 22 Diamond particles

[0191] 30 Copper-diamond composite

[0192] 32 Coarse-grained layer

[0193] 34, 36 microparticle layer

[0194] 50 metal film

[0195] 100 heat dissipation components

Claims

1. A heat dissipation component, comprising: A copper-diamond composite having a plurality of diamond particles dispersed in a metal matrix containing copper, and a metal film bonded to at least one surface of the copper-diamond composite; In at least one of the cross sections of the heat dissipation component in the stacking direction, the copper-diamond composite has: a coarse-grained layer including the coarse-grained diamond particles having a large particle size, a fine particle layer including the diamond particles having a particle size smaller than that of the coarse particles, Furthermore, the copper-diamond composite has a structure in which the fine particle layer is arranged on the bonding surface side of the copper-diamond composite and the metal film relative to the coarse particle layer.

2. The heat dissipation component according to claim 1, wherein: When the particle size distribution of the diamond particles is measured using an imaging particle size distribution measuring device, in the volume particle size distribution of the particle diameter of the diamond particles, The cumulative value of the coarse particles is 50% of the particle size D 50 Greater than 100 μm and less than 300 μm, The cumulative value of the particles is 50% of the particle size D 50 Less than 100 μm.

3. The heat dissipation component according to claim 1 or 2, wherein: The copper-diamond composite has a layered structure including the first fine particle layer and the coarse particle layer in this order in the layer thickness direction, or a layered structure including the first fine particle layer, the coarse particle layer, and the second fine particle layer in this order in the layer thickness direction.

4. The heat dissipation component according to claim 3, wherein: The thickness of the particle layer is 3 μm to 200 μm.

5. The heat dissipation component according to claim 1 or 2, wherein: The flatness of the bonding surface between the copper-diamond composite and the metal film is 30 μm or less.

6. The heat dissipation component according to claim 1 or 2, wherein: A ten-point average height Rz of a bonding surface between the copper-diamond composite and the metal film is 20 μm or less.

7. The heat dissipation component according to claim 1 or 2, wherein: The thermal conductivity of the copper-diamond composite is above 600 W / m·K.

8. The heat dissipation component according to claim 1 or 2, wherein: When the particle size distribution of the diamond particles is measured using an imaging particle size distribution measuring device, in the volume particle size distribution of the sphericity of the diamond particles, The cumulative value of the coarse particles is 50% of the sphericity D 50 It is above 0.

8.

9. An electronic device comprising: The heat dissipation component according to claim 1 or 2, and The electronic component is arranged on the heat dissipation component.

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