A near-net-shaping method of a six-sided copper-coated diamond / copper composite

Abstract

This invention provides a near-net-shape forming method for a six-sided copper-clad diamond / copper composite material and the resulting six-sided copper-clad diamond / copper composite material. The method includes the following steps: 1) mechanically mixing diamond powder and intermediate metal powder at a weight ratio of 9:1 to 1:6; 2) loading the mixed powder into a mold and pre-pressing it; 3) performing thermal diffusion treatment; 4) crushing, grinding, and sieving to obtain surface-metallized diamond; 5) uniformly mixing the metallized diamond powder, copper powder, and a forming agent, and pre-forming it to obtain a preform; 6) degreasing treatment; 7) placing the preform in a copper frame within a graphite plate-copper foil-preform-copper foil-graphite plate structure, then assembling it in a graphite mold, sintering it in an SPS system, and cutting it. The resulting six-sided copper-clad diamond / copper composite material exhibits good thermal conductivity and surface roughness.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation, and more specifically, to a near-net-shape forming method for a six-sided copper-clad diamond / copper composite material. Background Technology

[0002] With the continuous development of electronic technology and the increasing integration density of integrated circuits, third-generation GaN and SiC semiconductor chips have high power and high heat flux density, making heat dissipation a prominent issue. Advanced packaging thermal management technology is becoming increasingly important, and high-performance thermal packaging materials are receiving more and more attention. Diamond / copper composite materials are ideal for fourth-generation semiconductor electronic packaging. Their theoretical thermal conductivity far exceeds that of oxygen-free copper, reaching 900 W / (m·K). The coefficient of thermal expansion is related to the proportion of diamond in the composite material, and the average linear thermal expansion coefficient from room temperature to 100℃ is less than 8 × 10⁻⁶. -6 (1 / K) has excellent mechanical properties. However, it also has its limitations.

[0003] 1. The surface of diamond / copper composite material is very rough. Its surface roughness is related to the diamond particle size. The larger the diamond particle size, the higher the surface roughness, which can reach tens to hundreds of micrometers. However, in practical applications, this material needs to be welded with other materials and needs to achieve a certain degree of airtightness. Such a rough surface is difficult to meet the application requirements.

[0004] 2. Diamond is extremely hard and insulating, making it very difficult to process. The only effective processing methods are laser cutting and waterjet cutting, which are costly, difficult, and limited to a limited range of shapes.

[0005] 3. In practical applications, the surface of the processed diamond / copper composite material needs to be coated with other metal layers. The already processed surface is difficult to grind, the coating process is complicated, and the adhesion of the coated metal layers is weak, making it difficult to meet the requirements of high-temperature welding. Summary of the Invention

[0006] Technical issues

[0007] To address the existing problems of the aforementioned diamond / copper composite materials, this invention provides a near-net-shape forming method for a six-sided copper-clad diamond / copper composite material, as well as the six-sided copper-clad diamond / copper composite material prepared by this method. The six-sided copper-clad diamond / copper composite material according to this invention has high thermal conductivity and is easy to process.

[0008] Technical solution

[0009] According to a first aspect of the present invention, a near-net-shape forming method for a six-sided copper-clad diamond / copper composite material is provided, comprising the following steps:

[0010] Step 1: Mechanically mix diamond powder and intermediate metal powder in a weight ratio of 9:1 to 1:6;

[0011] Step 2: Load the mixed powder from Step 1 into the thermal diffusion mold in batches. After each loading, pre-compress the mixed powder. The loading and pre-compressing pressure is 5-30 MPa.

[0012] Step 3: Place the assembled heat diffusion mold into the SPS system for heat diffusion treatment. The treatment process is as follows:

[0013] No pressure is applied to the mixed powder during the sintering process;

[0014] Heating rate: 20~50℃ / min

[0015] Thermal diffusion temperature: 700~1050℃;

[0016] Insulation time: 30–180 min;

[0017] Cooling rate: 5-20℃ / min to 200℃, then cool to room temperature with the furnace after reaching 200℃;

[0018] Step 4: The thermally diffusing block processed in Step 3 is crushed, ground, and sieved to obtain surface-metallized diamond.

[0019] Step 5: Weigh the metallized diamond powder and copper powder, add the forming agent, mix the resulting mixture evenly, and then put it into a steel mold for preforming to obtain a preform;

[0020] Step 6: Place the preform obtained in Step 5 into a degreasing furnace for degreasing treatment. The degreasing process is as follows:

[0021] First stage heating rate: 5-10℃ / min;

[0022] First stage insulation temperature: 250~300℃;

[0023] Insulation time: 10–60 min;

[0024] Second stage heating rate: 5~10℃ / min;

[0025] Second stage insulation temperature: 320~400℃;

[0026] Insulation time: 10–60 min;

[0027] Cooling rate: Cools to room temperature along with the furnace;

[0028] Step 7: Place copper foil and graphite plate sequentially on the upper and lower sides of the degreased preform obtained in Step 6, forming a graphite plate-copper foil-preform-copper foil-graphite plate structure. Then, place this structure into a copper frame, and then place the assembled copper frame into a graphite mold for assembly. Finally, place the assembled mold into an SPS system for sintering. The copper frame is a copper plate with a hollow center. The hollow space is used to accommodate the graphite plate-copper foil-preform-copper foil-graphite plate structure. The thickness of the preform is less than the thickness of the copper frame, and the thickness of the graphite plate-copper foil-preform-copper foil-graphite plate structure is greater than the thickness of the copper plate. The sintering process is as follows:

[0029] Axial pressure: 20-50 MPa;

[0030] Heating rate: 50~100℃ / min

[0031] Sintering temperature: 750~950℃;

[0032] Insulation time: 5–30 minutes;

[0033] Cooling rate: 10-40℃ / min to 400℃, then cool to room temperature with the furnace.

[0034] The six-sided copper-coated diamond / copper composite material can be obtained by demolding and cutting.

[0035] Preferably, in step 1, the ratio of diamond to intermediate metal powder is 2:1 to 1:2, the particle size of diamond is 30 to 400 μm, the particle size of intermediate metal powder is 1 to 20 μm, and the mixing time is 4 to 12 h.

[0036] Preferably, the intermediate layer metal powder is chromium powder or tungsten powder.

[0037] Preferably, the mold used in step 2 is a pressureless thermal diffusion mold; more preferably, the pressureless mold includes a graphite mold with a limit and a graphite press head with a venting groove, wherein the limit is to prevent the graphite press head from applying pressure to the mixed powder during the sintering process.

[0038] Preferably, the thermal diffusion process in step 3 is as follows:

[0039] Heating rate: 30~40℃ / min

[0040] Thermal diffusion temperature: 700~1300℃;

[0041] Insulation time: 60–150 min;

[0042] Cooling rate: 10-20℃ / min to 200℃, then cool to room temperature with the furnace after reaching 200℃.

[0043] Preferably, the mesh screen used in step 4 is 50 to 1000 mesh.

[0044] Preferably, the volume ratio of surface-metallized diamond powder to copper powder is 2:8 to 7:3.

[0045] Preferably, the molding agent is paraffin or PEG, and the amount of molding agent used is 2 wt% to 10 wt% relative to the total weight of the metallized diamond powder and copper powder, more preferably 5 wt% to 8 wt%.

[0046] Preferably, the particle size of the copper powder is 200-400 mesh.

[0047] Preferably, in step 5, the metallized diamond and copper powder are mixed in a roller mixer for 1 to 4 hours, and the preforming pressure is 60 to 100 MPa.

[0048] Preferably, the degreasing process in step 6 is as follows:

[0049] First stage heating rate: 5-10℃ / min;

[0050] First stage insulation temperature: 280~300℃;

[0051] Insulation time: 10–60 min;

[0052] Second stage heating rate: 5~10℃ / min

[0053] Second stage insulation temperature: 340~380℃;

[0054] Insulation time: 10–60 min;

[0055] Cooling rate: Cools to room temperature along with the furnace.

[0056] Preferably, the sintering process in step 7 is as follows:

[0057] Axial pressure: 20-40 MPa;

[0058] Heating rate: 50~100℃ / min

[0059] Sintering temperature: 750~950℃;

[0060] Insulation time: 5–30 minutes;

[0061] Cooling rate: 10-40℃ / min to 400℃, then cool to room temperature with the furnace after reaching 400℃.

[0062] In step 7, the shape of the preform matches the shape of the cutout in the copper frame, and the cross-sectional area of ​​the preform in the thickness direction is slightly smaller than that of the cutout in the thickness direction to facilitate the placement of the preform. The area of ​​the copper foil is basically the same as the cross-sectional area in the thickness direction of the cutout, and the cross-sectional area in the thickness direction of the graphite plate is the same as that of the preform in the thickness direction.

[0063] The thickness of the preform is less than the thickness of the copper frame, and the thickness of the graphite plate-copper foil-preform-copper foil-graphite plate structure is greater than the thickness of the copper frame, thereby ensuring that the preform is sintered under axial pressure.

[0064] Preferably, in step 7, the graphite mold contains multiple identical copper frames stacked sequentially with aligned cutouts. A graphite plate with the same cutout structure is placed between adjacent copper frames, and during sintering, the preform in each copper frame is positioned at the midpoint of the copper frame's thickness. The cutouts of each copper frame are aligned to transmit axial pressure.

[0065] A graphite plate, with the same perforated structure as the copper frames, is used to separate two adjacent copper frames. The perforated portion of the graphite plate is aligned with the perforated portion of the copper frames to transmit axial pressure.

[0066] Preferably, each copper frame has multiple cutout spaces for accommodating the structure of graphite plate-copper foil-preform-copper foil-graphite plate.

[0067] The thickness of the copper foil is 0.1 to 3 mm, preferably 0.1 to 1 mm.

[0068] According to a second aspect of the invention, a six-sided copper-clad diamond / copper composite material is provided, which is prepared by the method according to the invention.

[0069] Preferably, the thermal conductivity of the six-sided copper-coated diamond / copper composite material is 630 W / (m·K) or higher, more preferably 650 W / (m·K) or higher, and even more preferably 680 W / (m·K) or higher.

[0070] Preferably, the surface roughness of the six-sided copper-coated diamond / copper composite material is less than 0.4 μm.

[0071] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0072] 1. By metallizing the diamond surface, the interfacial bonding force between diamond and copper is improved, and the interfacial thermal resistance between diamond and copper is reduced. The thermal conductivity of the prepared six-sided copper-coated diamond / copper composite material can reach 680 W / (m·K).

[0073] 2. By using the SPS system to perform thermal diffusion treatment on diamond and sintering of diamond and copper, near-net-shape six-sided copper-clad diamond / copper composite material is formed. The equipment requirements are simple, the process route is simple, the forming efficiency is high, and it is green and pollution-free.

[0074] 3. Through unique molding process and mold design, the defects of rough diamond / copper surface and the difficulty of surface plating are bypassed. It can directly form six-sided copper-coated diamond / copper composite materials with low surface roughness and strong bonding between the surface copper layer and the diamond / copper composite material, which can meet the requirements of high-temperature welding and reduce the welding cost at the application end.

[0075] 4. Six-sided copper-clad diamond / copper composite materials do not require processing of the composite material; only the copper needs to be cut. The processing difficulty is low, there are many processing methods, and the cost is low. Attached Figure Description

[0076] Figure 1 A diagram showing the thermally diffused pressureless graphite mold used in this invention;

[0077] Figure 2 A schematic diagram illustrating the six-sided copper-coated diamond / copper composite material molding according to the present invention;

[0078] Figure 3 A diagram showing a six-sided copper-coated diamond / copper composite material in a copper frame prepared according to Example 1 of the present invention;

[0079] Figure 4 This image shows the six-sided copper-coated diamond / copper composite material after cutting. Detailed Implementation

[0080] The present invention will now be described in detail with reference to embodiments. It should be understood that the embodiments described below are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0081] Example 1

[0082] Step 1: Weigh diamond powder and chromium powder at a weight ratio of 1:2. The average particle size of the diamond is 200μm and the particle size of the chromium powder is 2-10μm. Put them into a V-type powder mixer for mechanical mixing for 6 hours.

[0083] Step 2: The mixed powder from Step 1 is loaded into the pressureless thermal diffusion mold in several batches. After each loading, the mixed powder is pre-compressed at a pressure of 15 MPa. Figure 1As shown, the pressureless thermal diffusion mold includes a graphite mold with a limiting device and a graphite pressure head with venting grooves. The graphite mold with the limiting device has a cylindrical structure. The limiting device is used to prevent the graphite pressure head from applying pressure to the mixed powder during sintering. The graphite pressure head is used to keep the mixed powder in the mold cavity. During filling, the graphite pressure head at the bottom is first inserted, and powder is filled and pre-pressed. Then, filling continues until all the powder is filled. Finally, the top pressure head is inserted. During sintering, the pressure applied to the mold is only used to fix the mold and is not transmitted to the mixed powder. That is, the mixed powder is sintered under no pressure.

[0084] Step 3: Place the assembled heat diffusion mold into the SPS system for heat diffusion treatment. The treatment process is as follows:

[0085] Heating rate: 30~40℃ / min

[0086] Thermal diffusion temperature: 800℃;

[0087] Incubation time: 90 minutes;

[0088] Cooling rate: 15-20℃ / min to 200℃, then cool to room temperature with the furnace after reaching 200℃;

[0089] Step 4: The heat diffusion block processed in Step 3 is crushed, ground and sieved using a 150-mesh screen to obtain chromium-plated diamond.

[0090] Step 5: Weigh chrome-plated diamond powder and copper powder. The volume ratio of chrome-plated diamond powder to copper powder is 3.5:6.5, and the particle size of copper powder is 325 mesh. Add the molding agent paraffin wax. The weight ratio of chrome-plated diamond powder, copper powder and molding agent is 2:0.1. Mix the diamond, copper powder and paraffin wax evenly using a roller mixer for 2 hours.

[0091] Step 6: Load the mixed powder from Step 5 into a steel mold and press it into a preform. The pressing pressure is 60 MPa and the holding time is 30 seconds.

[0092] Step 7: Place the preform obtained in Step 6 into a degreasing furnace for degreasing treatment. The degreasing process is as follows:

[0093] First stage heating rate: 10℃ / min;

[0094] First stage insulation temperature: 280℃;

[0095] Incubation time: 30 minutes;

[0096] Second stage heating rate: 10℃ / min

[0097] Second stage insulation temperature: 350℃;

[0098] Incubation time: 30 minutes;

[0099] Cooling rate: Cools to room temperature along with the furnace;

[0100] Step 8: Place copper foil and graphite plate sequentially on the top and bottom sides of the preform obtained in Step 7, forming a structure of graphite plate-copper foil-preform-copper foil-graphite plate. Then, place this structure into a copper frame, and finally place the assembled copper frame into a graphite mold for further assembly. Figure 2 As shown, the left image depicts the assembled graphite mold, consisting of, from top to bottom, an upper pressure head, a multi-layered copper frame comprising graphite plate-copper foil-preform-copper foil-graphite plate, and a lower pressure head. A graphite plate with the same perforated structure as the copper frame is placed between adjacent copper frames. The perforated portion of the graphite plate aligns with the perforated portion of the copper frame to transmit axial pressure. The right image is an enlarged view of one layer of the copper frame comprising graphite plate-copper foil-preform-copper foil-graphite plate. The copper frame is a circular copper plate with two perforated portions in the middle. The space in the perforated portions accommodates the graphite plate-copper foil-preform-copper foil-graphite plate structure. The cross-sectional area (thickness direction) of the perforated portions is slightly larger than that of the preform to facilitate installation. The area of ​​the copper foil is approximately the same as the cross-sectional area of ​​the perforated portions, and the thickness of the copper foil is 0.2 mm. The cross-sectional area of ​​the graphite plate is the same as that of the preform. Furthermore, the thickness of the preform is less than the thickness of the copper plate, and the thickness of the graphite plate-copper foil-preform-copper foil-graphite plate structure is greater than the thickness of the copper plate, so that the preform can be sintered under axial pressure.

[0101] Step 9: Place the assembled mold from Step 8 into the SPS system for sintering, as follows:

[0102] Axial pressure: 30 MPa;

[0103] Heating rate: 70~80℃ / min

[0104] Sintering temperature: 890~920℃;

[0105] Keep warm for 10 minutes;

[0106] Cooling rate: 20℃ / min to 400℃, then cool to room temperature with the furnace after reaching 400℃;

[0107] Six-sided copper-coated diamond / copper composite material can be obtained by demolding and cutting.

[0108] Figure 3The image shows the prepared six-sided copper-clad diamond / copper composite material within a copper framework. The central portion of the image represents the six-sided copper-clad diamond / copper composite material. It can be seen that the six-sided copper-clad diamond / copper composite material was welded to the copper framework during sintering. The thermal conductivity of the prepared six-sided copper-clad diamond / copper composite material is 680 W / (m·K), measured using a laser thermal conductivity meter.

[0109] The surface roughness of the prepared six-sided copper-clad diamond / copper composite material is less than 0.4 μm, and the equipment used is a 3D laser measuring microscope. To more intuitively understand the surface roughness of the six-sided copper-clad diamond / copper composite material prepared according to the invention and the roughness of the diamond / copper composite material itself, the middle position of the six-sided copper-clad diamond / copper composite material was cut. The cut six-sided copper-clad diamond / copper composite material is shown below. Figure 4 As shown, the surface of the six-sided copper-coated diamond / copper composite material is smooth, while the cut surface of the diamond / copper composite material itself is very rough.

[0110] Example 2

[0111] Step 1: Weigh diamond powder and tungsten powder at a weight ratio of 2:1. The average particle size of the diamond is 200 μm and the average particle size of the tungsten powder is 8 μm. Put them into a V-type powder mixer for mechanical mixing for 8 hours.

[0112] Step 2: The mixed powder from Step 1 is loaded into a pressureless thermal diffusion mold (the same mold as in Example 1) in several batches. After each loading, the mixed powder is pre-compressed at a pressure of 15 MPa. During the sintering process, the pressure applied to the mold is only used to fix the mold and is not transmitted to the powder. That is, the mixed powder is sintered under no pressure.

[0113] Step 3: Place the assembled heat diffusion mold into the SPS system for heat diffusion treatment. The treatment process is as follows:

[0114] Heating rate: 30~40℃ / min

[0115] Thermal diffusion temperature: 900℃;

[0116] Incubation time: 90 minutes;

[0117] Cooling rate: 15-20℃ / min to 200℃, then cool to room temperature with the furnace after reaching 200℃;

[0118] Step 4: The heat diffusion block processed in Step 3 is crushed, ground and sieved using a 150-mesh screen to obtain tungsten-coated diamond.

[0119] Step 5: Weigh tungsten-plated diamond powder and copper powder. The volume ratio of tungsten-plated diamond powder to copper powder is 4:6, and the particle size of copper powder is 325 mesh. Add the molding agent paraffin wax. The weight ratio of tungsten-plated diamond powder, copper powder and molding agent is 2:0.1. Mix the diamond, copper powder and paraffin wax evenly using a roller mixer for 2 hours.

[0120] Step 6: Load the mixed powder from Step 5 into a steel mold and press it into a preform. The pressing pressure is 60 MPa and the holding time is 30 seconds.

[0121] Step 7: Place the preform obtained in Step 6 into a degreasing furnace for degreasing treatment. The degreasing process is as follows:

[0122] First stage heating rate: 10℃ / min;

[0123] First stage insulation temperature: 280℃;

[0124] Incubation time: 30 minutes;

[0125] Second stage heating rate: 10℃ / min

[0126] Second stage insulation temperature: 350℃;

[0127] Incubation time: 30 minutes;

[0128] Cooling rate: Cools to room temperature along with the furnace;

[0129] Step 8: Place the preform, copper foil and copper frame obtained in Step 7 into a graphite mold (the mold and filling method are the same as in Example 1) for assembly;

[0130] Step 9: Place the assembled mold from Step 8 into the SPS system for sintering, as follows:

[0131] Axial pressure: 30 MPa;

[0132] Heating rate: 70~80℃ / min

[0133] Sintering temperature: 890~920℃;

[0134] Keep warm for 10 minutes;

[0135] Cooling rate: 20℃ / min to 400℃, then cool to room temperature with the furnace after reaching 400℃;

[0136] The six-sided copper-coated diamond / copper composite material can be obtained by demolding.

[0137] The thermal conductivity of the prepared six-sided copper-coated diamond / copper composite material was 650 W / (m·K), and the measurement equipment was a laser thermal conductivity meter.

[0138] The surface roughness of the prepared six-sided copper-clad diamond / copper composite material is less than 0.4 μm, and the measurement equipment is a 3D laser measurement microscope.

[0139] The six-sided copper-clad diamond / copper composite material prepared according to the method of the present invention has excellent thermal conductivity and very low surface roughness.

Claims

1. A near-net-shape forming method for a six-sided copper-clad diamond / copper composite material, comprising the following steps: Step 1: Mechanically mix diamond powder and intermediate metal powder at a weight ratio of 9:1 to 1:6, wherein... The intermediate layer metal powder is chromium powder or tungsten powder; Step 2: The mixed powder from Step 1 is loaded into the thermal diffusion mold in several batches. After each loading, the mixed powder is pre-compressed. The pre-compressing pressure is 5~30MPa. During the sintering process, the pressure applied to the mold is only used to fix the mold and is not transmitted to the mixed powder. That is, the mixed powder is sintered under no pressure. Step 3: Place the assembled heat diffusion mold into the SPS system for heat diffusion treatment. The treatment process is as follows: Heating rate: 20~50℃ / min Thermal diffusion temperature: 700~1050℃; Incubation time: 30~180min; Cooling rate: 5~20℃ / min to 200℃, then cool to room temperature with the furnace after reaching 200℃; Step 4: The thermally diffusing block processed in Step 3 is crushed, ground, and sieved to obtain surface-metallized diamond. Step 5: Weigh the metallized diamond powder and copper powder, add the molding agent, and mix the resulting mixture evenly. Then, put it into a steel mold for preforming to obtain a preform. The volume ratio of surface-metallized diamond powder to copper powder is 2:8 to 7:

3. Step 6: Place the preform obtained in Step 5 into a degreasing furnace for degreasing treatment. The degreasing process is as follows: First stage heating rate: 5~10℃ / min; First stage insulation temperature: 250~300℃; Insulation time: 10~60min; Second stage heating rate: 5~10℃ / min; Second stage insulation temperature: 320~400℃; Insulation time: 10~60min; Cooling rate: Cools to room temperature along with the furnace; Step 7: Place copper foil and graphite plate sequentially on the upper and lower sides of the degreased preform obtained in Step 6, forming a graphite plate-copper foil-preform-copper foil-graphite plate structure. Then, place this structure into a copper frame, and then place the assembled copper frame into a graphite mold for assembly. Finally, place the assembled mold into an SPS system for sintering. The copper frame is a copper plate with a hollow center. The hollow space is used to accommodate the graphite plate-copper foil-preform-copper foil-graphite plate structure. The thickness of the preform is less than the thickness of the copper frame, and the thickness of the graphite plate-copper foil-preform-copper foil-graphite plate structure is greater than the thickness of the copper plate. The sintering process is as follows: Axial pressure: 20~50MPa; Heating rate: 50~100℃ / min Sintering temperature: 750~950℃; Insulation time: 5~30min; Cooling rate: 10~40℃ / min to 400℃, then cool to room temperature with the furnace. The six-sided copper-coated diamond / copper composite material can be obtained by demolding and cutting. The thickness of the copper foil is 0.1~3mm.

2. The near-net-shape forming method for six-sided copper-clad diamond / copper composite material according to claim 1, wherein, In step 1, the ratio of diamond to intermediate metal powder is 2:1 to 1:2, the particle size of diamond is 30 to 400 μm, the particle size of intermediate metal powder is 1 to 20 μm, and the mixing time is 4 to 12 h.

3. The near-net-shape forming method for six-sided copper-clad diamond / copper composite material according to claim 1, wherein, The mold used in step 2 is a pressureless thermal diffusion mold.

4. The near-net-shape forming method for six-sided copper-clad diamond / copper composite material according to claim 3, wherein, The pressureless thermal diffusion mold includes a graphite mold with a limit and a graphite press head with a venting groove, wherein the limit is to prevent the graphite press head from applying pressure to the mixed powder during the sintering process.

5. The near-net-shape forming method for a six-sided copper-clad diamond / copper composite material according to any one of claims 1 to 3, wherein, The mesh screen used in step 4 is 50-1000 mesh; And / or, the molding agent is paraffin or PEG, and the amount of molding agent is 2wt% to 10wt% relative to the total weight of the metallized diamond powder and copper powder; And / or, the particle size of the copper powder is 200-400 mesh; And / or, in step 5, the metallized diamond and copper powder are mixed in a roller mixer for 1-4 hours, and the pre-forming pressure is 60-100 MPa.

6. The near-net-shape forming method for a six-sided copper-clad diamond / copper composite material according to any one of claims 1 to 3, wherein, The degreasing process in step 6 is as follows: First stage heating rate: 5~10℃ / min; First stage insulation temperature: 280~300℃; Insulation time: 10~60min; Second stage heating rate: 5~10℃ / min Second stage insulation temperature: 340~380℃; Insulation time: 10~60min; Cooling rate: Cools to room temperature along with the furnace.

7. The near-net-shape forming method for a six-sided copper-clad diamond / copper composite material according to any one of claims 1 to 3, wherein, The sintering process in step 7 is as follows: Axial pressure: 20~40MPa; Heating rate: 50~100℃ / min Sintering temperature: 750~950℃; Insulation time: 5~30min; Cooling rate: 10~40℃ / min to 400℃, then cool to room temperature with the furnace after reaching 400℃.

8. The near-net-shape forming method for a six-sided copper-clad diamond / copper composite material according to any one of claims 1 to 3, wherein, In step 7, the graphite mold contains multiple identical copper frames stacked sequentially with aligned cutouts. A graphite plate with the same cutout structure is placed between two adjacent copper frames. During sintering, the preform in each copper frame is located at the middle of the copper frame thickness, and the cutouts of each copper frame are aligned to transmit axial pressure.

9. The near-net-shape forming method for six-sided copper-clad diamond / copper composite material according to claim 8, wherein, Each copper frame has multiple cutout spaces for accommodating the structure of graphite plate-copper foil-preform-copper foil-graphite plate.

10. A six-sided copper-clad diamond / copper composite material, which is prepared by a near-net-shape forming method of the six-sided copper-clad diamond / copper composite material according to any one of claims 1 to 9.

11. The six-sided copper-clad diamond / copper composite material according to claim 10, wherein, The thermal conductivity of the six-sided copper-coated diamond / copper composite material is above 630 W / (m·K); And / or, the surface roughness of the six-sided copper-clad diamond / copper composite material is less than 0.4 μm.

12. The six-sided copper-clad diamond / copper composite material according to claim 11, wherein, The thermal conductivity of the six-sided copper-coated diamond / copper composite material is above 650 W / (m·K).

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