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

Abstract

The application discloses a high-thermal-conductivity diamond / copper composite material and an ultrahigh-pressure preparation method, and relates to the technical field of composite materials. The ultrahigh-pressure preparation method comprises the following steps: 1) diamond micro-powder plating; 2) laying a thermal-conductivity layer; 3) ultrahigh-pressure high-temperature sintering; and 4) sintering body finishing and assembling. Compared with the prior art, the application has the advantages that an efficient heat conduction path from a high-heat-flux chip to a structural member is realized, interface thermal resistance is effectively reduced, and heat diffusion capacity is enhanced; the mechanical stability and service life of the whole composite material are improved; processing time and energy consumption are reduced, and production cost is lowered; the distribution of thermal conductivity is optimized, the density between layered materials is improved, the heat conduction requirement from the chip to the heat dissipation member is met, and the overall material quality and product performance are improved.

Description

Technical Field

[0001] This invention relates to the field of copper-based composite material preparation technology, specifically a high thermal conductivity diamond / copper composite material and an ultra-high pressure preparation method. Background Technology

[0002] With the continuous increase in the power density of electronic components, heat dissipation has become a key factor restricting the performance of high-power electronic devices. While traditional heat dissipation materials such as aluminum and copper have high thermal conductivity, their heat dissipation capacity is nearing its limit in high-power, high-computing-power servers, making it difficult to meet the ever-increasing heat dissipation demands. Furthermore, existing heat dissipation materials face numerous challenges in terms of interfacial thermal resistance, density, manufacturing process complexity, and cost.

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

[0004] Statistical studies on improving the performance of heat sink materials mainly focus on heat conduction, structural irregular 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 reliable use of higher power chips in immersion liquid-cooled servers is currently the primary challenge to overcome for the stable operation of high computing power / power servers. Summary of the Invention

[0005] The purpose of this 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 of existing heat dissipation materials in high computing power / high power servers, high interfacial thermal resistance, insufficient density, complex preparation process and high cost.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a high thermal conductivity diamond / copper composite material, including a heat sink copper structural component, the heat sink copper structural component including a substrate, the top of the substrate being provided with a filling groove, and the filling groove being provided with a first thermally conductive layer, a second thermally conductive layer, a third thermally conductive layer and a fourth thermally conductive layer from bottom to top;

[0007] Both the first and third thermal conductive layers are made of diamond micro powder with a double coating of Ti and Cu.

[0008] The second thermally conductive layer is made of Ti-coated diamond micropowder;

[0009] The fourth thermally conductive layer is made of pure copper powder;

[0010] The top of the fourth thermally conductive layer is flush with the filling groove.

[0011] As a preferred embodiment, the diamond powder used in the first, second, and third thermal conductive layers has a particle size of 150μm-220μm.

[0012] As a preferred embodiment, the thickness of the first thermally conductive layer and the third thermally conductive layer is 1-3 mm.

[0013] As a preferred embodiment, the thickness of the second thermally conductive layer is 4-6 mm.

[0014] As a preferred embodiment, the thickness of the fourth thermally conductive layer is 0.5-1 mm.

[0015] A method for preparing a high thermal conductivity diamond / copper composite material under ultra-high pressure, specifically including the following steps:

[0016] 1) Diamond micropowder coating: Diamond / copper volume percentage 33-50:67-50. The diamond micropowder undergoes Ti and Cu plating processes. Ti plating is performed using vacuum ion plating with a pure Ti rod target (30-40mm diameter). High-energy particles generated by arc discharge bombard the Ti rod, causing Ti to deposit on the surface of the diamond micropowder. The Ti film thickness is 0.15-0.2μm. The Ti-plated diamond micropowder is then further coated with Cu by magnetron sputtering, resulting in a coating thickness of approximately 10-80nm.

[0017] 2) Laying the thermal conductive layer: Lay a layer of diamond micro powder with Ti and Cu double plating at the bottom of the copper structure of the heat sink, with a thickness of 1-3mm; lay a layer of diamond micro powder with Ti plating on top, with a thickness of 4-6mm; lay another layer of diamond micro powder with Ti and Cu double plating, 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: The copper heat sink structure and the 4 layers of gradient diamond / copper powder are placed in a six-sided top pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6GPa, the sintering temperature is 800-950℃, and the temperature is held for 25-35 minutes.

[0019] 4) Sintered body finishing and assembly: The sintered body is finished to ensure that the copper in the outermost pure copper powder layer is properly assembled with the heating element, thereby reducing the thermal resistance between the interfaces, increasing the heat transfer channels, and improving the heat transfer efficiency.

[0020] As a preferred embodiment, the process parameters for vacuum ion plating Ti in step 1) are as follows: the vacuum chamber must reach a density of 5 × 10⁻⁶ before operation. - 5 Pa, the working vacuum level must meet 1×10 -3 Up to 5×10-3 For Pa, the diamond powder needs to be preheated to 350℃, and the target power (DC) should be set to 100–300W, the deposition rate to 15–20nm / min, and the deposition time to 10min. For Cu plating, the target power (DC) should be set to 100W, the deposition rate to 10–12nm / min, and the deposition time to 2–8min.

[0021] The advantages of this invention compared to the prior art are:

[0022] 1. By adopting a gradient structure design of diamond and copper, an efficient heat conduction path is achieved from the high heat flux density chip to the structural components, effectively reducing the interface thermal resistance, enhancing the heat diffusion capability, and significantly improving the heat dissipation efficiency in high computing power / high power servers.

[0023] 2. By using vacuum ion plating Ti and magnetron sputtering Cu plating technologies, the wettability and bonding of the diamond-copper interface are improved, thereby enhancing the overall mechanical stability and service life of the composite material.

[0024] 3. By introducing a six-sided top ultra-high pressure and high temperature preparation process, combined with gradient powder laying technology, the sintering process of the material is made 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 lowered.

[0025] 4. By using a diamond / copper layered gradient design, the thermal conductivity distribution is optimized, the density between the layers 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. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the double-coated diamond micro powder of the present invention;

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

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

[0029] As shown in the figure: 1. Diamond micro 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. Copper heat sink structure, 8. First thermal conductive layer. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally 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 terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first," "second," and "third" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, the use of terms such as "horizontal," "vertical," and "sag" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "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, "multiple" means at least two.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

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

[0036] Both the first thermal conductive layer 8 and the third thermal conductive layer 5 are double-coated diamond micro powder with Ti and Cu plating.

[0037] The second thermally conductive layer 6 is coated with Ti diamond micro powder;

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

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

[0040] In specific implementation of this invention:

[0041] 1) Diamond / copper volume percentage 33-50: 67-50. Diamond micropowder undergoes Ti and Cu plating processes. Ti plating is performed using vacuum ion plating with a pure Ti rod target (30-40mm diameter). High-energy particles generated by arc discharge bombard the Ti rod, causing Ti to deposit on the surface of the diamond micropowder. The Ti film thickness is 0.15-0.2μm. The Ti-plated diamond micropowder is then further coated with Cu by magnetron sputtering, resulting in a coating thickness of approximately 10-80nm.

[0042] 2) Spread diamond micro powder with Ti and Cu double plating at the bottom and second-to-top of the copper structure of the heat sink, with a thickness of 1-3mm; spread a layer of Ti-plated diamond micro 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-layered diamond micropowder, the second thermal conductive layer is Ti-plated diamond micropowder, and the fourth thermal conductive layer is pure copper powder. This allows the Ti-plated and Cu-plated double-layered diamond micropowder to better integrate with the copper of the heat sink's copper structure, forming a more perfect interface relationship. At the same time, the Cu-plated layers at the positions of the first and third thermal conductive layers and the Ti-plated layer at the position of the sandwiched second thermal conductive layer have good wettability, maintaining a good interface relationship. The pure copper of the fourth thermal conductive layer is in direct contact with the heat-generating components of the high-power server chip after assembly, and the pure copper has a high heat transfer ratio with the heat-generating components of the chip.

[0044] 3) Then, the copper heat sink structure and the 4 layers of gradient diamond / copper powder were placed in a six-sided top pyrophyllite block for ultra-high pressure and high temperature sintering, and held at 800-950℃ for 30±5 min under 6GPa pressure.

[0045] 4) The sintered body is finely processed to ensure that the outermost copper layer fits snugly with the heating element, thereby reducing the thermal resistance between the interfaces, increasing the heat transfer channels, and improving the heat transfer efficiency.

[0046] The diamond micron powder has a particle size of 150μm-220μm; the process parameters for vacuum ion plating Ti are: the vacuum chamber needs to reach 5×10⁻⁶ m² before starting operation. -5 Pa, the working vacuum level must meet: 1×10 -3 Up to 5×10 -3During the Pa process, the diamond micro powder needs to be preheated to 350℃ (too low a temperature will result in insufficient coating adhesion, while too high a temperature may damage the diamond surface structure). The target power (DC power) is set to 100–300W, the deposition rate to 15–20nm / min, and the deposition time to 10min. For Cu plating, the target power (DC power) is set to 100W, the deposition rate to 10–12nm / min, and the deposition time to 2–8min. After the six-sided top ultra-high pressure sintering, the powder-coated positions of the heat sink copper structure are sintered to form a gradient diamond / copper composite material, which, from bottom to top, are: Ti and Cu double-coated diamond / copper layer, Ti-coated diamond / copper layer, Ti and Cu double-coated diamond / copper layer, and copper layer.

[0047] The thermal diffusivity of the diamond / copper layered gradient material prepared by the above-mentioned layered gradient powder + six-sided top press ultra-high pressure and high temperature sintering process is greatly improved, and the thermal conduction and heat dissipation capacity of the structural components are also significantly improved. This effectively solves the shortcomings of traditional diamond / copper composite materials in terms of heat dissipation and mechanical properties, and provides a more reliable solution for heat dissipation technology of high computing power servers.

[0048] The principle of this invention lies in the improvement of the wettability and bonding at the diamond-copper interface through a gradient structure design of diamond and copper, combined with vacuum ion plating of Ti and magnetron sputtering of Cu, thereby reducing the interfacial thermal resistance. The ultra-high pressure, high temperature sintering process further enhances the material's density and thermal diffusivity, thus significantly improving heat dissipation efficiency.

[0049] Example 1

[0050] 1. Diamond micro powder coating: Diamond micro powder with a particle size of 150μm was selected and vacuum ion-plated with Ti to form a Ti film with a thickness of 0.15μm. Subsequently, Cu was deposited by magnetron sputtering to form a Cu layer with a thickness of 10nm.

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

[0052] 3. Ultra-high pressure and high temperature sintering: The copper heat sink structure and the four layers of gradient diamond / copper powder are placed in a six-sided top pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6 GPa, the sintering temperature is 800℃, and the holding time is 25 min.

[0053] 4. Sintered body finishing and assembly: The sintered body is finished to ensure that the copper in the outermost pure copper powder layer is properly assembled and bonded to the heating components.

[0054] Example 2

[0055] 1. Diamond micro powder coating: Diamond micro powder with a particle size of 220μm was selected for vacuum ion plating of Ti, and the Ti film thickness was 0.2μm. Subsequently, Cu was deposited by magnetron sputtering, and the Cu layer thickness was 80nm.

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

[0057] 3. Ultra-high pressure and high temperature sintering: The copper heat sink structure and the four layers of gradient diamond / copper powder are placed in a six-sided top pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6 GPa, the sintering temperature is 950℃, and the holding time is 35 min.

[0058] 4. Sintered body finishing and assembly: The sintered body is finished to ensure that the copper in the outermost pure copper powder layer is properly assembled and bonded to the heating components.

[0059] Table 1 shows the performance indicators of diamond / copper layered gradient materials prepared under ultra-high pressure and traditional diamond / copper materials.

[0060]

[0061] Table 1

[0062] This 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 high temperature sintering process, the thermal conductivity and mechanical properties of the material are significantly improved, making it suitable for the heat dissipation requirements of high computing power / high power servers.

[0063] The present invention and its embodiments have been described above. This description is not restrictive. The structures and material ratios in the embodiments are only some embodiments of the present invention and are used only to explain the specific implementation process of the present invention. All other embodiments obtained based on the ideas 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 device includes a copper heat sink structure, which includes a base and a filling groove on the top of the base. The filling groove contains a first thermally conductive layer, a second thermally conductive layer, a third thermally conductive layer, and a fourth thermally conductive layer arranged sequentially from bottom to top. Both the first and third thermal conductive layers are made of diamond micro powder with a double coating of Ti and Cu. The second thermally conductive layer is made of Ti-coated diamond micropowder; The fourth thermally conductive layer is made of pure copper powder; The top of the fourth thermally conductive layer is flush with the filling groove.

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

3. The high thermal conductivity diamond / copper composite material according to claim 1, characterized in that: The thickness of the first and third thermal conductive layers 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 thermally conductive 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 thermally conductive layer is 0.5-1mm.

6. A method for preparing high thermal conductivity diamond / copper composite material under ultra-high pressure, characterized in that, Specifically, the following steps are included: 1) Diamond micro powder coating: Diamond / copper volume percentage 33-50:67-50. The diamond micro powder is treated with Ti and Cu plating processes. Ti plating of diamond micro powder is carried out by vacuum ion plating, using pure Ti rod target material with a target size of 30-40mm in diameter. High-energy particles generated by arc discharge bombard the Ti rod, causing Ti to be deposited on the surface of the diamond micro powder. The thickness of the Ti film is 0.15-0.2μm. The Ti-plated diamond micro powder is then subjected to magnetron sputtering to coat Cu, with a coating thickness of 10-80nm. 2) Laying the thermal conductive layer: Lay a layer of diamond micro powder with Ti and Cu double plating at the bottom of the copper structure of the heat sink, with a thickness of 1-3mm; lay a layer of diamond micro powder with Ti plating on top, with a thickness of 4-6mm; lay another layer of diamond micro powder with Ti and Cu double plating, 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: The copper heat sink structure and the 4 layers of gradient diamond / copper powder are placed in a six-sided top pyrophyllite block for ultra-high pressure and high temperature sintering. The sintering pressure is 6GPa, the sintering temperature is 800-950℃, and the temperature is held for 2535min. 4) Sintered body finishing and assembly: The sintered body is finished to ensure that the copper in the outermost pure copper powder layer is properly assembled with the heating element, thereby reducing the thermal resistance between the interfaces, increasing the heat transfer channels, and improving the heat transfer efficiency.

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

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