Novel diamond vapor chamber and manufacturing method thereof

Abstract

The invention discloses a novel diamond vapor chamber and a manufacturing method thereof. The manufacturing method comprises the following steps: S10, preparing a diamond and copper composite substrate; s20, preparing diamond micro-columns on the diamond and copper composite substrate; and S30, filling diamond micro powder between the upper cover plate and the bottom plate, and sealing the edges of the upper cover plate and the bottom plate. By means of the ultrahigh heat conductivity coefficient of diamond, compared with a traditional copper-based uniform temperature plate and a diamond and copper composite substrate, the overall heat conductivity of the bottom plate is improved, and compared with a cover plate prepared by plating the surface of diamond with copper, the interface shear strength of the cover plate is 30-35 Mpa and is higher than that of a scheme of plating the surface with copper. The diamond amp is prepared by using an MPCVD growth technology; the heat conductivity of the copper composite material can reach 1200-1500 W / (m.K), so that when the bottom plate is in contact with a heat source, heat can be quickly conducted to internal working medium liquid, the heat dissipation efficiency is improved by more than three times compared with that of a copper-based scheme, and the heat transfer efficiency and the structural stability of the bottom plate are greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical heat dissipation, and in particular relates to a novel diamond temperature balancing plate and a manufacturing method thereof. Background Art

[0002] As the electronics industry evolves towards miniaturization and high integration, the heat flux density per unit area is growing exponentially. Taking smartphone SoC chips as an example, their peak power consumption has exceeded 15 W, and the heat flux density has reached 800 W / cm², resulting in a local temperature gradient exceeding 100 ℃ / mm, causing a performance degradation rate of more than 30%. Traditional heat dissipation solutions such as aluminum fins and copper-based heat pipes are limited to one-dimensional linear heat transfer modes (thermal conductivity ≤ 400W / (m·K)), and are difficult to meet the temperature uniformity requirements of three-dimensional non-uniform thermal fields. Traditional heat pipes can only transfer heat from the evaporation end to the remote condensation end, while the vapor chamber achieves uniform heat distribution through surface contact, effectively reducing the temperature of local hot spots. For example, in server CPU cooling, the vapor chamber can reduce the temperature difference on the chip surface from the 10℃ of the heat pipe to within 2℃. In addition, the thickness of the vapor chamber can be compressed to less than 0.3mm, making it more suitable for ultra-thin electronic devices. A vapor chamber (VC) is a highly efficient heat dissipation device based on a two-phase flow cycle. Its core principle is to achieve rapid heat transfer and uniform distribution through the evaporation, diffusion, condensation, and capillary recirculation of a working fluid. As a two-dimensional upgrade of heat pipe technology, a vapor chamber overcomes the linear heat transfer limitations of traditional heat pipes and can rapidly diffuse heat from a localized heat source across an entire surface. Its thermal conductivity can be hundreds of times greater than that of copper, making it a key technology for addressing high-heat flux heat dissipation. A vapor chamber is typically constructed from a closed cavity made of a highly thermally conductive metal (such as oxygen-free copper or a copper-aluminum composite). After evacuation, a small amount of working fluid (such as water, ethanol, acetone, or ammonia) is injected, and a capillary structure (such as sintered copper powder, multi-layer copper mesh, or etched microgrooves) is designed. However, the performance of a vapor chamber is affected by the thermal conductivity of the copper material, its long-term reliability, and its adaptability to extreme environments. Due to the limited thermal conductivity of copper itself, the heat transfer efficiency from the heat source to the interior of the temperature equalizer is affected to a certain extent; at the same time, due to the insufficient compatibility between the working fluid and the copper material, the degradation rate of thermal resistance is greater than 10% after 2000 hot and cold cycles; in high-temperature environments, the saturated vapor pressure of the working fluid is too high, which will cause the risk of cavity deformation, so more suitable materials are needed to improve the thermal conductivity and reliability of the temperature equalizer.

[0003] Diamond has a thermal conductivity of up to 2000 W / (m·K), far exceeding that of traditional metal materials such as copper (398 W / (m·K)) and aluminum (200 W / (m·K)). Its phonon-dominated thermal conductivity mechanism maintains efficient heat transfer performance even at high temperatures. Homogenized diamond sheets produced using microwave plasma chemical vapor deposition (MPCVD) technology can achieve isotropic thermal diffusion, significantly reducing heat flux density gradients and avoiding the generation of local hot spots. Therefore, the excellent properties of diamond material can greatly improve the heat dissipation performance of the vapor chamber, enabling it to operate more efficiently and stably. There is a method for preparing a diamond copper temperature plate in the prior art. The key technical solution is to use the method of chemically plating copper on the surface of a diamond sheet to make a plate-shaped diamond copper cover plate. However, the diamond copper plate prepared by this solution has a large difference in lattice constants due to the large difference in diamond's cubic structure and copper's face-centered cubic structure. Therefore, lattice mismatch defects are easily formed at the interface. The measured shear strength of the interface is usually less than 20 Mpa, so its structural stability is low. At the same time, the copper plating thickness of this patent is greater than 1 μm. Due to the large difference in thermal expansion coefficients between diamond and copper (the thermal expansion coefficient of diamond is 0.8×10 -6 / ℃, copper is 16.5×10 -6 / °C) and the thin copper layer is prone to falling off at high temperatures. Although this patent improves thermal conductivity compared to traditional copper cover plates, the strength and stability of the cover plate need to be improved.

[0004] At the same time, another method of the existing technology uses a mixture of diamond powder and copper powder to sinter and form a diamond molten salt mixture for the capillary structure inside the temperature equalizing plate. Although the thermal conductivity is improved to a certain extent compared with traditional copper powder, the molten salt mixture is only 60% to 75% of the thermal conductivity of pure diamond powder, and the heat transfer performance of its capillary structure needs to be improved. Summary of the Invention

[0005] To solve the above problems, the present invention provides a method for manufacturing a novel diamond temperature balancing plate, comprising the following steps: S10, preparing a diamond and copper composite substrate; S20, preparing diamond micropillars on a diamond and copper composite substrate; S30, filling the space between the upper cover plate and the bottom plate with diamond powder, and sealing the edges of the upper cover plate and the bottom plate.

[0006] Preferably, the S10 adopts an MPCVD diamond growth process to grow a diamond film on the copper base plate, with a thickness of 0.5-0.6 mm as an evaporation end contact layer.

[0007] Preferably, the S10 includes the following steps: S11, placing the copper base plate in an ethanol solution to clean it and remove impurities and dirt on the surface; S12, grinding the surface of the copper base plate with diamond particles having a particle size of 0.5 μm until scratches caused by grinding can be observed under a microscope and reach a preset uniformity and density; S13, mixing acetone and diamond powder with a particle size of less than 30 nm to form a suspension, placing a copper substrate in the solution, and performing ultrasonication with an ultrasonic instrument to seed seed crystals on the surface of the copper substrate; S14. After the ultrasonic treatment is completed, the copper base plate is taken out and ultrasonically cleaned with ethanol first, and then with deionized water to remove loosely adhered diamond particles or large diamond particles or dust on the surface. Finally, the surface of the copper base plate is blown dry with an air gun and placed in the MPCVD equipment for growth.

[0008] Preferably, the S10 adopts MPCVD process parameters with a microwave output power of 1000w, a methane content of 2%, a hydrogen content of 10%, and the rest Ar. The purity of the three gases is greater than 99.999%, and the total flow rate is controlled at 90-110sccm, the deposition pressure is 11.8KPa, the deposition temperature is 650°C, and the deposition time is 1.4h-1.6h.

[0009] Preferably, the step S20 specifically includes the following steps: S21, cleaning the grown diamond and copper composite substrate, making a mask of corresponding size according to the distribution of the diamond support pillars to protect the support pillars and expose the parts to be etched; S22, etching depth of 0.1-0.2mm, array with pore size of 5-50μm, porosity of 30%-60%, diamond microcolumn height of 0.3-0.5mm, forming the microcolumn array on the diamond and copper composite substrate by MPCVD hydrogen and oxygen atmosphere etching or by laser cutting.

[0010] Preferably, the cavity gap area formed between the bottom plate and the upper cover plate in said S30 is filled with processed diamond powder to cover the cavity part in the cavity to form a capillary structure, wherein both the bottom plate and the upper cover plate are diamond and copper composite substrates prepared with diamond microcolumns.

[0011] Preferably, the step S30 specifically includes the following steps: S31, using organic solvent to ultrasonically clean the surface of diamond powder to remove organic pollutants and residual particles to ensure a clean surface before etching; S32 uses reactive ion etching equipment, using oxygen-containing active gases to generate active free radicals through plasma excitation. These react with carbon atoms on the surface of the diamond powder to form volatile products. The oxygen plasma promotes surface oxidation, forming hydroxyl hydrophilic groups on the surface of the diamond powder. S33, after etching, cleaning with deionized water or a weak acid solution to remove byproducts and unreacted active substances generated on the surface of the diamond powder; S34, filling the processed diamond powder into the cavity gap area formed between the bottom plate and the upper cover plate to form a capillary structure, and encapsulating the bottom plate and the upper cover plate by vacuum brazing or diffusion welding to make the vacuum degree 10 -3 ~10 -4 Pa, and finally sealed by cold welding.

[0012] Preferably, after filling the diamond powder in S34, fine copper meshes are welded on the bottom plate and the upper cover plate respectively to seal the diamond powder.

[0013] Preferably, S33 further comprises evaluating the surface hydrophilicity by a contact angle meter, and the surface contact angle of the diamond powder is below 10°.

[0014] Based on the above purpose, the present invention also provides a new type of diamond temperature equalizing plate made by the above manufacturing method, including an upper cover plate, a bottom plate, diamond powder and a fine copper mesh, wherein the bottom plate and the upper cover plate are both diamond and copper composite substrates prepared with diamond microcolumns, and the diamond powder fills the cavity gap area formed between the bottom plate and the upper cover plate. The bottom plate and the upper cover plate are welded with a fine copper mesh to seal the diamond powder.

[0015] The beneficial effects of the present invention include at least: This patented temperature spreader utilizes the ultra-high thermal conductivity of diamond to greatly improve its heat dissipation performance.

[0016] Leveraging diamond's ultra-high thermal conductivity, the diamond & copper composite substrate, grown using MPCVD technology, improves the overall thermal conductivity of the baseplate compared to traditional copper-based vapor chambers. Compared to a cover plate made of copper-plated diamond, its interfacial shear strength is 30-35 MPa, exceeding that of a copper-plated solution. While existing patents disclose an equivalent thermal conductivity of 800 W / (m·K) for a copper-plated diamond composite structure, the diamond & copper composite material produced using MPCVD growth technology achieves a thermal conductivity of 1200-1500 W / (m·K). This allows the baseplate to quickly transfer heat to the internal working fluid when in contact with a heat source, increasing heat dissipation efficiency by more than three times compared to copper-based solutions, significantly improving the baseplate's heat transfer efficiency and structural stability.

[0017] This patented temperature equalizer is lighter.

[0018] Since the traditional temperature plate is made of copper, its density is about 8.96g / cm 3 , while the density of diamond is about 3.52g / cm 3 If diamond material is used instead of copper material as the internal structure of the heat spreader and the filling of the inner core, the weight of the heat spreader will be greatly reduced, and the heat spreader will be lightweight.

[0019] This patented vapor chamber has higher reliability and thermal stability in extreme environments.

[0020] Since the melting point (3550℃) and thermal decomposition temperature (>700℃) of diamond material itself are far higher than those of conventional materials, it can work stably in a wide temperature range of -200℃ to 500℃, and is suitable for thermal control systems outside the aerospace cabin. Its thermal expansion coefficient (0.8×10 -6 / K) and semiconductor chip materials (such as SiC: 4.0×10 -6 / K) match is excellent, reducing the risk of interface failure caused by thermal cycling stress. Therefore, the diamond and copper composite substrate and internal diamond micropillar support used in this vapor chamber effectively improve its reliability and thermal stability in extreme environments. Because it can operate normally at temperatures exceeding 500°C, it excels in heat dissipation for high-power devices, making it an ideal solution for current high-power applications. Furthermore, because diamond maintains its thermal conductivity in radiation environments, this patented vapor chamber can provide long-term thermal management support for nuclear reactor cooling systems.

[0021] This patented temperature equalizing plate has the advantages of corrosion resistance, vibration resistance and other stability.

[0022] Because diamond material itself has good chemical stability and strong tolerance to acids, alkalis, organic solvents and high humidity environments, it can be used in corrosive industrial scenarios without additional packaging. Therefore, it has high working reliability in the heat dissipation of electronic products or corrosive environments. At the same time, diamond has high hardness and durability, so it is not easy to wear during use, especially in long-term vibration environments. It can maintain its structural stability, so it has great advantages in motor heat dissipation applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention provides the following drawings for illustration: Figure 1 This is an exploded structural diagram of a novel diamond temperature absorbing plate according to an embodiment of the present invention; Figure 2 Schematic top view of a novel diamond temperature balancing plate according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the bottom plate structure of the new diamond temperature equalizing plate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] See also Figure 1-Figure 3 , which is a new type of diamond temperature-maintaining plate manufactured using a new diamond temperature-maintaining plate manufacturing method, includes an upper cover plate 11, a bottom plate 12, diamond powder 20 and a fine copper mesh 30. Among them, the bottom plate 12 and the upper cover plate 11 are both diamond and copper composite substrates prepared with diamond micropillars 13. The diamond powder 20 fills the cavity gap area formed between the bottom plate 12 and the upper cover plate 11. The bottom plate 12 and the upper cover plate 11 are welded with a fine copper mesh 30 to seal the diamond powder 20.

[0026] The preparation method comprises the following steps: S10, preparing a diamond and copper composite substrate; S20, preparing diamond micropillars 13 on a diamond and copper composite substrate; S30 , filling the space between the upper cover plate 11 and the bottom plate 12 with diamond powder, and sealing the edges of the upper cover plate 11 and the bottom plate 12 .

[0027] S10 adopts MPCVD diamond growth process to grow a diamond film on the copper base plate 12 with a thickness of 0.5-0.6mm as the evaporation end contact layer.

[0028] S10 includes the following steps: S11, placing the copper base plate 12 in an ethanol solution to clean it and remove impurities and dirt on the surface; S12, grinding the surface of the copper base plate 12 with diamond particles having a particle size of 0.5 μm until the scratches caused by grinding can be observed under a microscope and reach a preset uniformity and density; S13, acetone and diamond powder 20 with a particle size of less than 30 nm are mixed to form a suspension, and the copper base plate 12 is placed in the solution and ultrasonicated for 30 minutes using an ultrasonic instrument to plant seed crystals on the surface; S14, after the ultrasonic treatment is completed, the copper base plate 12 is taken out and ultrasonically cleaned with ethanol for 10 minutes, and then ultrasonically cleaned with deionized water for 10 minutes to remove diamond particles that are not firmly adhered to the surface or diamond particles with large particle size or dust. Finally, the surface of the copper base plate 12 is blown dry with an air gun and placed in the MPCVD equipment to prepare for growth.

[0029] The S10 uses MPCVD process parameters with a microwave output power of 1000w, a methane content of 2%, a hydrogen content of 10%, and the rest being Ar. The purity of the three gases is greater than 99.999%, and the total flow rate is controlled at 90-110sccm, the deposition pressure is 11.8kPa, the deposition temperature is 650°C, and the deposition time is 1.4h-1.6h. The diamond and copper composite substrate prepared by this process has thicker diamond and copper layers, which can effectively overcome the stress changes caused by thermal expansion at high temperatures. At the same time, the ductility of the copper substrate (elongation at break > 40%) can partially offset the brittleness of diamond. At the same time, the diamond & copper composite substrate layer under this process is more chemically stable at high temperatures, can work continuously for 1000 hours in a 300°C environment, and has a thermal conductivity attenuation rate of less than 3%, making it suitable for high power density scenarios (such as 5G base station GaN devices). S20 specifically includes the following steps: S21, cleaning the grown diamond and copper composite substrate, making a mask of corresponding size according to the distribution of the diamond support pillars to protect the support pillars and expose the parts to be etched; S22, an array with an etch depth of 0.1-0.2mm, a pore size of 5-50μm, a porosity of 30%-60%, and a height of 0.3-0.5mm for the diamond micropillars 13. The micropillar array 13 is formed on a diamond and copper composite substrate by MPCVD etching in a hydrogen and oxygen atmosphere, or by laser cutting. This process utilizes the design of the diamond micropillar array 13 within the heat plate cavity to enhance structural strength, prevent deformation caused by internal high pressure, and provide an additional thermal conductivity path.

[0030] In S30, the cavity gap area formed between the base plate 12 and the upper cover plate 11 is filled with processed diamond powder 20 to cover the cavity part in the cavity to form a capillary structure, wherein the base plate 12 and the upper cover plate 11 are both diamond and copper composite substrates prepared with diamond microcolumns 13.

[0031] In a specific embodiment, the diamond powder 20 used in S30 has a particle size of 70-80 mesh, and the diamond powder 20 is cleaned and hydrophilic pre-treated to adapt to the working fluid inside the heat pipe. Specifically, the following steps are included: S31: Use acetone, ethanol and other organic solvents to ultrasonically clean the diamond surface to remove organic pollutants and residual particles to ensure a clean surface before etching.

[0032] S32 uses reactive ion etching (RIE) equipment and active gases containing oxygen (O2) to generate active free radicals (such as O⁺ and F⁺) through plasma excitation, which react with carbon atoms on the diamond surface to generate volatile products (such as CO and CO2). Oxygen plasma can promote surface oxidation and form hydrophilic groups such as hydroxyl groups (-OH) on the diamond surface.

[0033] S33, after etching, use deionized water or weak acid solution to clean the surface to remove byproducts and unreacted active substances. The surface hydrophilicity is evaluated using a contact angle meter. The contact angle of the optimized diamond surface can be reduced to below 10°.

[0034] S34, fill the processed diamond powder 20 into the cavity of the upper cover plate 11 and the bottom plate 12, and weld the fine copper mesh 30 on the upper cover plate 11 and the bottom plate 12, seal the diamond powder 20 to form a multi-layer heat-conducting hot runner in the entire cavity, accelerate the heat conduction at the bottom, make it quickly conduct heat to the top and condense and reflux, and accelerate the condensed pure water to return to the bottom evaporation area for heat exchange, thereby improving the thermal circulation efficiency of the temperature equalizer.

[0035] After the diamond powder 20 is filled, the upper cover plate 11 and the bottom plate 12 are packaged by vacuum brazing or diffusion welding to ensure that the vacuum degree reaches 10 -3 ~10 -4 Pa, and finally the working fluid is vacuum injected and sealed by cold welding to complete the preparation of the diamond temperature balancing plate.

[0036] In a specific embodiment, the present invention can be used as a heat dissipation solution for mobile phones or laptop computers in the field of consumer electronics: Currently, due to limited space, mobile phones or laptop computers in consumer electronic products cannot use overly large heat pipe radiators or water-cooled radiators, so the lightweight and compact temperature spreader solution has become a popular solution for heat dissipation of mobile phones and laptop computers. The diamond temperature spreader proposed in this patent can more efficiently meet the heat dissipation requirements of existing electronic products than traditional temperature spreaders.

[0037] Solution for data center server cooling: Since data center servers have high requirements for the reliability of the cooling system and are basically not disassembled once assembled, their reliability and service life must be higher than that of general radiators. This patented diamond heat spreader can provide a lightweight cooling solution for data center servers due to its high thermal stability, long service life, and corrosion resistance.

[0038] Solving the heat dissipation solution for the electric drive system of new energy vehicles: Since the electric drive system of new energy vehicles has high requirements for its seismic stability, the seismic resistance of traditional temperature spreaders is difficult to meet and requires additional processing before heat dissipation adaptation. The diamond temperature spreader of this patent itself has a certain degree of seismic resistance, so its heat dissipation capacity in harsh environments is more advantageous.

[0039] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for manufacturing a novel diamond temperature balancing plate, characterized in that: The following steps are involved: S10, preparing a diamond and copper composite substrate; S20, preparing diamond micropillars on a diamond and copper composite substrate; S30, filling the space between the upper cover plate and the bottom plate with diamond powder, and sealing the edges of the upper cover plate and the bottom plate.

2. The method for manufacturing the novel diamond temperature balancing plate according to claim 1, characterized in that: The S10 adopts the MPCVD diamond growth process to grow a diamond film on the copper base plate, and the film thickness is 0.5-0.6mm as the evaporation end contact layer.

3. The method for manufacturing the novel diamond temperature balancing plate according to claim 1, characterized in that: The S10 includes the following steps: S11, placing the copper base plate in an ethanol solution to clean it and remove impurities and dirt on the surface; S12, grinding the surface of the copper base plate with diamond particles having a particle size of 0.5 μm until scratches caused by grinding can be observed under a microscope and reach a preset uniformity and density; S13, mixing acetone and diamond powder with a particle size of less than 30 nm to form a suspension, placing a copper substrate in the solution, and performing ultrasonication with an ultrasonic instrument to seed seed crystals on the surface of the copper substrate; S14. After the ultrasonic treatment is completed, the copper base plate is taken out and ultrasonically cleaned with ethanol first, and then with deionized water to remove loosely adhered diamond particles or large diamond particles or dust on the surface. Finally, the surface of the copper base plate is blown dry with an air gun and placed in the MPCVD equipment for growth.

4. The method for manufacturing the novel diamond temperature balancing plate according to claim 2, characterized in that: The S10 adopts MPCVD process parameters with a microwave output power of 1000w, a methane content of 2%, a hydrogen content of 10%, and the rest Ar. The purity of the three gases is greater than 99.999%, and the total flow rate is controlled at 90-110sccm, the deposition pressure is 11.8KPa, the deposition temperature is 650°C, and the deposition time is 1.4h-1.6h.

5. The method for manufacturing the novel diamond temperature balancing plate according to claim 1, characterized in that: The S20 specifically includes the following steps: S21, cleaning the grown diamond and copper composite substrate, making a mask of corresponding size according to the distribution of the diamond support pillars to protect the support pillars and expose the parts to be etched; S22, etching depth of 0.1-0.2mm, array with pore size of 5-50μm, porosity of 30%-60%, diamond microcolumn height of 0.3-0.5mm, forming the microcolumn array on the diamond and copper composite substrate by MPCVD hydrogen and oxygen atmosphere etching or by laser cutting.

6. The method for manufacturing a novel diamond temperature balancing plate according to claim 1, characterized in that: In said S30, the cavity gap area formed between the bottom plate and the upper cover plate is filled with processed diamond powder to cover the cavity part in the cavity to form a capillary structure, wherein both the bottom plate and the upper cover plate are diamond and copper composite substrates prepared with diamond microcolumns.

7. The method for manufacturing a novel diamond temperature balancing plate according to claim 1, characterized in that: The S30 specifically includes the following steps: S31, using organic solvent to ultrasonically clean the surface of diamond powder to remove organic pollutants and residual particles to ensure a clean surface before etching; S32 uses reactive ion etching equipment, using oxygen-containing active gases to generate active free radicals through plasma excitation. These react with carbon atoms on the surface of the diamond powder to form volatile products. The oxygen plasma promotes surface oxidation, forming hydroxyl hydrophilic groups on the surface of the diamond powder. S33, after etching, cleaning with deionized water or a weak acid solution to remove byproducts and unreacted active substances generated on the surface of the diamond powder; S34, filling the processed diamond powder into the cavity gap area formed between the bottom plate and the upper cover plate to form a capillary structure, and encapsulating the bottom plate and the upper cover plate by vacuum brazing or diffusion welding to make the vacuum degree 10 -3 ~10 -4 Pa, and finally sealed by cold welding.

8. The method for manufacturing the novel diamond temperature balancing plate according to claim 7, characterized in that: In the above-mentioned S34, after the diamond powder is filled, fine copper meshes are welded on the bottom plate and the upper cover plate respectively to seal the diamond powder.

9. The method for manufacturing a novel diamond temperature balancing plate according to claim 7, characterized in that: The S33 further includes evaluating the surface hydrophilicity by using a contact angle meter, and the surface contact angle of the diamond powder is below 10°.

10. A novel diamond temperature balancing plate manufactured by the manufacturing method according to any one of claims 1 to 9, characterized in that: It includes an upper cover plate, a base plate, diamond powder and a fine copper mesh. The base plate and the upper cover plate are both diamond and copper composite substrates with diamond microcolumns prepared thereon. Diamond powder fills the cavity gap area formed between the base plate and the upper cover plate. Fine copper mesh is welded to the base plate and the upper cover plate to seal the diamond powder.

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