High-thermal-conductivity diamond / copper composite material and ultrahigh-pressure preparation method

Abstract

The high-thermal-conductivity diamond / copper composite material comprises a cooling fin red copper structural part, the cooling fin red copper structural part comprises a base body, a filling groove is formed in the top of the base body, and a first heat conduction layer, a second heat conduction layer, a third heat conduction layer and a fourth heat conduction layer are arranged in the filling groove. The ultrahigh-pressure preparation method comprises the following steps: (1) diamond micro-powder coating; 2) laying a heat conduction layer; 3) performing ultrahigh-pressure high-temperature sintering; and (4) finish machining and assembling of the sintered body. Compared with the prior art, the method has the advantages that a high-efficiency heat conduction path from a high-heat-flux chip to a structural part is realized, the interface thermal resistance is effectively reduced, and the thermal diffusivity is enhanced; the overall mechanical stability and service life of the composite material are improved; the processing time and energy consumption are reduced, and the production cost is reduced; the heat conductivity distribution is optimized, the density among the layered materials is improved, the heat conduction requirement from a chip to a heat dissipation piece is met, and the overall material quality and the product performance are improved.

Description

Technical Field

[0001] The invention relates to the technical field of copper-based composite material preparation, in particular to a high thermal conductivity diamond / copper composite material and an ultrahigh pressure preparation method. Background Art

[0002] As the power density of electronic components continues to increase, heat dissipation has become a key factor restricting the performance of high-power electronic devices. Although traditional heat dissipation materials such as aluminum and copper have high thermal conductivity, their heat dissipation capacity is close to the limit in high-power, high-computing servers, and it is difficult to meet the growing heat dissipation needs. In addition, existing heat dissipation materials have many problems in terms of interface thermal resistance, density, preparation process complexity and cost.

[0003] In recent years, diamond / copper composites have gradually become a research hotspot for high-power heat dissipation materials due to their excellent thermal conductivity and mechanical properties. However, existing diamond / copper composites still have deficiencies in interface bonding strength, thermal diffusion coefficient and preparation process, making it difficult to meet the heat dissipation requirements of high-power servers.

[0004] According to statistics, relevant scholars' research on the performance improvement of heat sink materials is mainly focused on thermal conduction, structural special-shaped design, composite material design, and preparation methods. How to further improve the heat transfer and heat dissipation performance of heat sink materials and develop a gradient structure diamond copper heat dissipation material to meet the stable and high-reliability use of higher-power chips in immersion liquid cooling servers is the primary problem to be overcome for the stable operation of high-computing power / power servers. Summary of the invention

[0005] The purpose of the present invention is to provide a high thermal conductivity diamond / copper composite material and an ultra-high pressure preparation method to solve the problems of insufficient heat transfer and heat dissipation capacity, large interface thermal resistance, insufficient density, complex preparation process and high cost of existing heat dissipation materials on high computing power / high power servers.

[0006] In order to solve the above technical problems, the present invention provides a technical solution as follows: a high thermal conductivity diamond / copper composite material, comprising a heat sink copper structure, the heat sink copper structure comprising a substrate, a filling groove is provided on the top of the substrate, and a first heat conduction layer, a second heat conduction layer, a third heat conduction layer, and a fourth heat conduction layer are sequentially provided in the filling groove from bottom to top;

[0007] The first heat-conducting layer and the third heat-conducting layer are both Ti-plated and Cu-plated double-layer diamond micropowder;

[0008] The second heat-conducting layer is Ti-plated diamond powder;

[0009] The fourth heat conducting layer is pure copper powder;

[0010] The top of the fourth heat conducting layer is flush with the filling groove.

[0011] As a preferred solution, the diamond powder used in the first heat-conducting layer, the second heat-conducting layer and the third heat-conducting layer has a particle size of 150 μm-220 μm.

[0012] As a preferred solution, the thickness of the first heat-conducting layer and the third heat-conducting layer is 1-3 mm.

[0013] As a preferred solution, the thickness of the second heat-conducting layer is 4-6 mm.

[0014] As a preferred solution, the thickness of the fourth heat-conducting layer is 0.5-1 mm.

[0015] An ultra-high pressure preparation method for a high thermal conductivity diamond / copper composite material comprises the following steps:

[0016] 1) Diamond powder coating: diamond / copper volume percentage 33-50:67-50. Diamond powder is plated with Ti and Cu. Diamond powder is plated with Ti by vacuum ion plating. Pure Ti rod target material is selected. Target size: diameter 30-40mm. High-energy particles are generated by arc discharge to bombard Ti rod, so that Ti is deposited on the surface of diamond powder. Ti film thickness: 0.15-0.2μm; Ti-plated diamond powder is then magnetron sputtered to plate Cu, and the coating thickness is about 10-80nm;

[0017] 2) Laying the thermal conductive layer: Lay the diamond powder with double layers of Ti and Cu on the bottom of the copper structure of the heat sink, with a thickness of 1-3mm; Lay a layer of Ti-plated diamond powder on the upper layer, with a thickness of 4-6mm; Lay another layer of Ti-plated and Cu-plated diamond powder, with a thickness of 1-3mm, and lay a layer of pure copper powder on the top layer, with a thickness of 0.5-1mm;

[0018] 3) Ultra-high pressure and high temperature sintering: Place the copper structure of the heat sink and the laid 4 layers of gradient diamond / copper powder in a hexagonal pyrophyllite block for ultra-high pressure and high temperature sintering, with a sintering pressure of 6 GPa and a sintering temperature of 800-950°C, followed by heat preservation for 25-35 minutes;

[0019] 4) Sintered body finishing and assembly: The sintered body is finished after sintering to make the copper at the outermost pure copper powder layer fit with the heat-generating components, reduce the thermal resistance between the interfaces, increase the heat transfer channel, and improve the heat transfer efficiency.

[0020] As a preferred solution, the process parameters of vacuum ion plating Ti in step 1) are: the vacuum chamber needs to reach 5×10 - 5 Pa, the working vacuum degree must meet 1×10 -3 Up to 5×10-3 For Pa, diamond powder needs to be preheated to 350°C, and the target power DC power is set to 100-300W, the deposition rate is 15-20nm / min, and the deposition time is 10min; for Cu plating, the target power DC power is set to 100W, the deposition rate is 10-12nm / min, and the deposition time is 2-8min.

[0021] The advantages of the present invention compared with the prior art are:

[0022] 1. By adopting the gradient structure design of diamond and copper, an efficient heat conduction path is achieved from high heat flux density chips to structural parts, which effectively reduces the interface thermal resistance, enhances the heat diffusion capacity, and significantly improves the heat dissipation efficiency in high computing power / high power servers.

[0023] 2. Through vacuum ion plating Ti and magnetron sputtering Cu plating technology, the wettability and bonding of the diamond and copper interface are improved, and the overall mechanical stability and service life of the composite material are enhanced.

[0024] 3. By introducing the hexagonal top ultra-high pressure and high temperature preparation process and combining it with the gradient powder laying technology, the sintering process of the material is faster and more efficient, the process is simpler, the complexity of the preparation process is reduced, the processing time and energy consumption are reduced, and the production cost is reduced.

[0025] 4. Through the layered gradient design of diamond / copper, the thermal conductivity distribution is optimized, the density between the layered materials is improved, the heat conduction requirements from the chip to the heat sink are met, and the overall material quality and product performance are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the double-coated diamond micropowder of the present invention;

[0027] Figure 2 It is a layered gradient structure diagram of the present invention;

[0028] Figure 3 It is a top view of the heat sink structure of the present invention.

[0029] As shown in the figure: 1. Diamond powder, 2. Ti plating layer, 3. Cu plating layer, 4. Fourth thermal conductive layer, 5. Third thermal conductive layer, 6. Second thermal conductive layer, 7. Heat sink copper structure, 8. First thermal conductive layer. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] In the description of the embodiments of the present invention, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, "plurality" means at least 2.

[0034] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] A high thermal conductivity diamond / copper composite material, comprising a heat sink copper structure 7, the heat sink copper structure comprising a substrate, a filling groove is provided on the top of the substrate, and a first heat conduction layer 8, a second heat conduction layer 6, a third heat conduction layer 5, and a fourth heat conduction layer 4 are sequentially provided in the filling groove from bottom to top;

[0036] The first heat-conducting layer 8 and the third heat-conducting layer 5 are both Ti-plated and Cu-plated double-layer diamond powder;

[0037] The second heat conducting layer 6 is Ti-plated diamond powder;

[0038] The fourth heat conducting layer 7 is pure copper powder;

[0039] The top of the fourth heat conducting layer 7 is flush with the filling groove.

[0040] The present invention is specifically implemented:

[0041] 1) Diamond / copper volume percentage 33-50:67-50. Diamond powder is plated with Ti and Cu. Diamond powder is plated with Ti by vacuum ion plating. Pure Ti rod target material is selected. Target size: diameter 30-40mm. High-energy particles are generated by arc discharge to bombard Ti rod, so that Ti is deposited on the surface of diamond powder. Ti film thickness: 0.15-0.2μm; Ti-plated diamond powder is then plated with Cu by magnetron sputtering. The coating thickness is about 10-80nm.

[0042] 2) Spread Ti-plated and Cu-plated diamond powder at the bottom and the second top of the heat sink copper structure with a thickness of 1-3mm; spread a layer of Ti-plated diamond powder between the two with a thickness of 4-6mm; and spread a layer of pure copper powder on the outermost layer with a thickness of 0.5-1mm;

[0043] The first and third thermal conductive layers are both Ti-plated and Cu-plated double-layer diamond powders, the second thermal conductive layer is Ti-plated diamond powders, and the fourth thermal conductive layer is pure copper powder, so that the Ti-plated and Cu-plated double-layer diamond powders can better integrate with the copper of the heat sink copper structure to form a more perfect interface relationship. At the same time, the Cu-plated layers at the first and third thermal conductive layers and the Ti-plated layers at the second thermal conductive layer sandwiched in the middle have better wettability and maintain a better interface relationship; the pure copper of the fourth thermal conductive layer is in direct contact with the high-power server chip heating components after assembly, and the pure copper has a higher heat transfer ratio with the chip heating components;

[0044] 3) Then, the heat sink copper structure and the laid 4 layers of gradient diamond / copper powder are placed in a hexagonal pyrophyllite block for ultra-high pressure and high temperature sintering, and the temperature is kept at 800-950°C for 30±5min under a pressure of 6GPa;

[0045] 4) The sintered body is finely processed to make the outermost layer of copper fit the heat-generating components, reduce the thermal resistance between interfaces, increase the heat transfer channel, and improve the heat transfer efficiency.

[0046] The particle size of diamond powder is 150μm-220μm; the process parameters of vacuum ion plating Ti are: the vacuum chamber must reach 5×10 -5 Pa, working vacuum degree must meet: 1×10 -3 Up to 5×10 -3Pa, diamond powder needs to be preheated to 350℃ (too low temperature will lead to insufficient adhesion of the coating, too high temperature may damage the surface structure of the diamond), set the target power DC power: 100-300W, deposition rate: 15-20nm / min, deposition time 10min; for Cu plating, set the target power DC power: 100W, deposition rate: 10-12nm / min, deposition time 2-8min; after ultra-high pressure sintering of the six-sided top, the powder-laying position of the heat sink copper structural parts is sintered to form a gradient diamond / copper composite material, from bottom to top: Ti-plated and Cu-plated double-layer diamond / copper layer, Ti-plated diamond / copper layer, Ti-plated and Cu-plated double-layer diamond / copper layer, and copper layer.

[0047] The thermal diffusion coefficient of the diamond / copper layered gradient material prepared by the above layered gradient powder + six-sided top press ultra-high pressure and high temperature sintering process has been greatly improved, and the thermal conductivity and heat dissipation capacity of the structural parts have also been significantly improved, effectively solving the shortcomings of traditional diamond / copper composite materials in heat dissipation and mechanical properties, and providing a more reliable solution for high-computing power server heat dissipation technology.

[0048] The principle of the present invention is to improve the wettability and bonding of the diamond-copper interface and reduce the interface thermal resistance through the gradient structure design of diamond and copper, combined with vacuum ion plating Ti and magnetron sputtering Cu plating technology. Through the ultra-high pressure and high temperature sintering process, the density and thermal diffusion coefficient of the material are further improved, thereby significantly improving the heat dissipation efficiency.

[0049] Example 1

[0050] 1. Diamond powder coating: Diamond powder with a particle size of 150 μm was used for vacuum ion plating of Ti, with a Ti film thickness of 0.15 μm. Then, magnetron sputtering was used for Cu plating, with a Cu layer thickness of 10 nm.

[0051] 2. Laying the thermal conductive layer: Lay the Ti-plated and Cu-plated double-layer diamond powder on the bottom of the heat sink copper structure with a thickness of 1mm; lay a layer of Ti-plated diamond powder on the upper layer with a thickness of 4mm; lay another layer of Ti-plated and Cu-plated double-layer diamond powder with a thickness of 1mm, and lay a layer of pure copper powder on the top layer with a thickness of 0.5mm.

[0052] 3. Ultra-high pressure and high temperature sintering: The copper structure of the heat sink and the 4 layers of gradient diamond / copper powder are placed in a hexagonal pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6 GPa, the sintering temperature is 800 ° C, and the holding time is 25 minutes.

[0053] 4. Finishing and assembly of sintered body: The sintered body is finished after sintering to make the copper at the outermost pure copper powder layer fit the heating components.

[0054] Example 2

[0055] 1. Diamond powder coating: Diamond powder with a particle size of 220 μm was used for vacuum ion plating of Ti, with a Ti film thickness of 0.2 μm. Then, magnetron sputtering was used for Cu plating, with a Cu layer thickness of 80 nm.

[0056] 2. Laying the thermal conductive layer: Lay the Ti-plated and Cu-plated double-layer diamond powder on the bottom of the heat sink copper structure with a thickness of 3mm; lay a layer of Ti-plated diamond powder on the upper layer with a thickness of 6mm; lay another layer of Ti-plated and Cu-plated double-layer diamond powder with a thickness of 3mm, and lay a layer of pure copper powder on the top layer with a thickness of 1mm.

[0057] 3. Ultra-high pressure and high temperature sintering: The copper structure of the heat sink and the 4 layers of gradient diamond / copper powder are placed in a hexagonal pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6 GPa, the sintering temperature is 950 ° C, and the holding time is 35 minutes.

[0058] 4. Finishing and assembly of sintered body: The sintered body is finished after sintering to make the copper at the outermost pure copper powder layer fit the heating components.

[0059] Table 1 shows the indexes of diamond / copper layered gradient materials prepared by ultrahigh pressure and traditional diamond / copper materials

[0060]

[0061] Table 1

[0062] The present invention provides a high thermal conductivity diamond / copper composite material and an ultra-high pressure preparation method. Through gradient structure design and ultra-high pressure and high temperature sintering process, the thermal conductivity and mechanical properties of the material are significantly improved, which is suitable for the heat dissipation requirements of high computing power / high power servers.

[0063] The present invention and its embodiments are described above. Such description is not restrictive. The structures and material ratios in the embodiments are only part of the embodiments of the present invention and are only used to explain the specific implementation process of the present invention. All other embodiments obtained based on the concept of the present invention are within the protection scope of the present invention.

Claims

1. A high thermal conductivity diamond / copper composite material, characterized in that: The heat sink copper structure comprises a base, a filling groove is provided on the top of the base, and a first heat conducting layer, a second heat conducting layer, a third heat conducting layer, and a fourth heat conducting layer are provided in the filling groove from bottom to top in sequence; The first heat-conducting layer and the third heat-conducting layer are both Ti-plated and Cu-plated double-layer diamond micropowder; The second heat-conducting layer is Ti-plated diamond powder; The fourth heat conducting layer is pure copper powder; The top of the fourth heat conducting layer is flush with the filling groove.

2. The high thermal conductivity diamond / copper composite material according to claim 1, characterized in that: The particle size of the diamond powder used in the first heat-conducting layer, the second heat-conducting layer and the third heat-conducting layer is 150 μm-220 μm.

3. The high thermal conductivity diamond / copper composite material according to claim 1, characterized in that: The thickness of the first heat-conducting layer and the third heat-conducting layer is 1-3 mm.

4. The high thermal conductivity diamond / copper composite material according to claim 1, characterized in that: The thickness of the second heat-conducting layer is 4-6 mm.

5. The high thermal conductivity diamond / copper composite material according to claim 1, characterized in that: The thickness of the fourth heat-conducting layer is 0.5-1 mm.

6. An ultra-high pressure preparation method for a high thermal conductivity diamond / copper composite material, characterized in that: The specific steps include: 1) Diamond powder coating: diamond / copper volume percentage 33-50:67-50. Diamond powder is plated with Ti and Cu. Diamond powder is plated with Ti by vacuum ion plating. Pure Ti rod target material is selected. Target size: diameter 30-40mm. High-energy particles are generated by arc discharge to bombard Ti rod, so that Ti is deposited on the surface of diamond powder. Ti film thickness: 0.15-0.2μm; Ti-plated diamond powder is then magnetron sputtered to plate Cu, and the coating thickness is about 10-80nm; 2) Laying the thermal conductive layer: Lay the diamond powder with double layers of Ti and Cu on the bottom of the copper structure of the heat sink, with a thickness of 1-3mm; Lay a layer of Ti-plated diamond powder on the upper layer, with a thickness of 4-6mm; Lay another layer of Ti-plated and Cu-plated diamond powder, with a thickness of 1-3mm, and lay a layer of pure copper powder on the top layer, with a thickness of 0.5-1mm; 3) Ultra-high pressure and high temperature sintering: Place the copper structure of the heat sink and the laid 4 layers of gradient diamond / copper powder in a hexagonal pyrophyllite block for ultra-high pressure and high temperature sintering, with a sintering pressure of 6 GPa and a sintering temperature of 800-950°C, followed by heat preservation for 25-35 minutes; 4) Sintered body finishing and assembly: The sintered body is finished after sintering to make the copper at the outermost pure copper powder layer fit with the heat-generating components, reduce the thermal resistance between the interfaces, increase the heat transfer channel, and improve the heat transfer efficiency.

7. The ultra-high pressure preparation method of a high thermal conductivity diamond / copper composite material according to claim 6, characterized in that: The process parameters of vacuum ion plating Ti in step 1) are: the vacuum chamber should reach 5×10 -5 Pa, the working vacuum degree must meet 1×10 -3 Up to 5×10 -3 For Pa, diamond powder needs to be preheated to 350°C, and the target power DC power is set to 100-300W, the deposition rate is 15-20nm / min, and the deposition time is 10min; for Cu plating, the target power DC power is set to 100W, the deposition rate is 10-12nm / min, and the deposition time is 2-8min.

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