Copper diamond heat dissipation substrate

Abstract

The embodiment of the utility model provides a copper-diamond heat dissipation substrate which comprises a copper-diamond composite layer, a first metal layer and a second metal layer, the copper-diamond composite layer comprises a copper-diamond material and a metal frame, the copper-diamond material is arranged in a through hole of the metal frame, and the first metal layer is arranged on the metal frame. The first metal layer is arranged on the upper layer of the copper-diamond composite layer, the second metal layer is arranged on the lower layer of the copper-diamond composite layer, and the copper-diamond composite layer is characterized in that the first metal layer is fixedly connected with the copper-diamond composite layer through a first solder layer, and the second metal layer is fixedly connected with the copper-diamond composite layer through a second solder layer. And the second metal layer is fixedly connected with the copper-diamond composite layer through the second solder layer.

Description

Technical Field

[0001] This application relates to the technical field of heat dissipation substrates, and particularly to a copper diamond heat dissipation substrate. Background Art

[0002] A copper diamond heat dissipation substrate is a high-performance composite heat dissipation material that combines the high thermal conductivity of copper with the low thermal expansion coefficient and high hardness of diamond to meet the requirements of modern electronic devices for efficient heat dissipation and thermal management. The copper diamond substrate adopts a sandwich structure, specifically, the copper diamond material is used as the core layer, and other metal materials are covered around it and on both the upper and lower sides to form a sandwich-like layered structure.

[0003] In the existing copper diamond heat dissipation substrates, first, a mixture of metallized diamond particles and copper powder is pre-pressed to obtain a copper diamond green body, and then the copper diamond green body is placed into the pre-set holes of a copper plate. After covering copper powder on both the upper and lower sides of the copper plate, sintering is carried out to obtain a copper diamond heat dissipation substrate with a sandwich structure.

[0004] However, the upper and lower copper layers in the above heat dissipation substrate are not tightly combined with the middle copper diamond composite layer, unable to meet the needs of actual applications. Summary of the Utility Model

[0005] This application provides a copper diamond heat dissipation substrate to ensure the tight combination of the copper diamond composite layer with the upper and lower copper layers, improve the firmness of the heat dissipation substrate, and meet the needs of different scenarios.

[0006] In a first aspect of this application, a copper diamond heat dissipation substrate is provided, which includes a copper diamond composite layer, a first metal layer, and a second metal layer. The copper diamond composite layer includes a copper diamond material and a metal frame. The copper diamond material is disposed in the through holes of the metal frame. The first metal layer is disposed on the upper layer of the copper diamond composite layer, and the second metal layer is disposed on the lower layer of the copper diamond composite layer. The first metal layer is fixedly connected to the copper diamond composite layer through a first solder layer, and the second metal layer is fixedly connected to the copper diamond composite layer through a second solder layer.

[0007] In this application, the copper diamond composite layer is fixedly connected to the upper and lower copper layers through solder layers. Solder connection can form a uniform and dense alloy layer. In addition, solder connection can also reduce the risk of connection failure caused by defects such as pores and cracks. Therefore, using solder connection can ensure the stability and reliability of the connection quality. During long-term use, the solder connection can also maintain a good connection state and performance.

[0008] In a possible implementation, the copper diamond heat dissipation substrate includes a boss region and a cavity corresponding to the boss region.

[0009] In this application, the copper-diamond heat dissipation substrate is obtained by stamping a flat plate to form bosses and corresponding cavities, so as to adapt to different installation environments and broaden the application scenarios of the heat dissipation substrate.

[0010] In a possible implementation, the copper-diamond material is located within the boss region.

[0011] In this application, since the copper-diamond material is brittle and not conducive to stamping, setting the copper-diamond material within the boss region can avoid the copper-diamond material from being stressed during stamping. Only the periphery of the copper-diamond material needs to be stamped, which is convenient for processing.

[0012] In a possible implementation, the edge of the boss region is rounded.

[0013] In this application, setting the edge of the boss region to be rounded can avoid cracking due to stress concentration during the stress process and reduce the processing difficulty.

[0014] In a possible implementation, the material of the first metal layer is copper, aluminum, copper alloy or aluminum alloy.

[0015] In this application, the first metal layer can adopt a variety of different materials, improving the flexibility of processing.

[0016] In a possible implementation, the material of the second metal layer is copper, aluminum, copper alloy or aluminum alloy.

[0017] In this application, the second metal layer can adopt a variety of different materials, improving the flexibility of processing.

[0018] In a possible implementation, the first solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium.

[0019] In this application, the first solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium, which can improve the bonding tightness between the copper-diamond composite layer and the copper layer.

[0020] In a possible implementation, the second solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium.

[0021] In this application, the second solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium, which can improve the bonding tightness between the copper-diamond composite layer and the copper layer.

[0022] In a possible implementation, the thickness of the copper-diamond material is the same as the thickness of the metal frame.

[0023] In this application, the thickness of the copper diamond material is the same as that of the metal frame, thereby ensuring that the copper diamond material will not move up and down after being placed in the through holes of the metal frame, and improving the structural stability. Description of the Drawings

[0024] Figure 1 FIG. 6 is a schematic structural diagram of a heat dissipation substrate of the prior art;

[0025] Figure 2 FIG. 10 is a schematic structural diagram of the copper diamond heat dissipation substrate of the present application;

[0026] Figure 3 FIG. 14 is a schematic assembly diagram of the copper diamond heat dissipation substrate of the present application;

[0027] Figure 4 FIG. 18 is a schematic assembly diagram of the copper diamond composite layer in the present application;

[0028] Figure 5 FIG. 22 is a schematic diagram of the stamping positions of the copper diamond heat dissipation substrate in the present application;

[0029] Figure 6 FIG. 26 is a schematic comparison diagram of the copper diamond heat dissipation substrate before and after stamping in the present application;

[0030] Figure 7 FIG. 30 is a schematic diagram of the reinforcing ribs of the copper diamond heat dissipation substrate in the present application. Detailed Description of the Embodiments

[0031] The following describes the embodiments of the present application in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Those of ordinary skill in the art will know that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0032] The terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order different from that shown or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or devices.

[0033] With the rapid development of microelectronics technology and power electronics technology, the core electronic devices at the chip level and module level are continuously evolving towards smaller size, higher functional integration, and higher power density. This has led to an increasing heat flux density in electronic devices, posing higher and higher requirements for the thermal conductivity, density, and thermal expansion coefficient of heat sinks.

[0034] The heat dissipation substrate usually serves as a bridge between the heat source and the heat sink, directly contacting the heat-generating components to quickly absorb and conduct heat. The heat sink is responsible for further dissipating this heat into the surrounding environment to ensure that the operating temperature of the heat-generating components remains within a safe range.

[0035] The heat dissipation substrate is a specially designed PCB (printed circuit board). It tightly combines the copper foil layer and heat dissipation materials (such as aluminum, copper, or composite materials) through special manufacturing processes, thus achieving efficient heat conduction and dissipation. This design enables the heat dissipation substrate to effectively conduct heat from electronic components to the surrounding environment, keeping the components within an appropriate operating temperature range.

[0036] The main function of the heat dissipation substrate is to quickly conduct the heat generated by integrated circuits or other electronic components to the surrounding environment, preventing the components from being damaged or having their performance degraded due to overheating. This is crucial for improving the stability and reliability of the circuit.

[0037] By effectively dissipating heat, the heat dissipation substrate can reduce the operating temperature of electronic components, minimize performance degradation and lifespan shortening caused by high temperature, thereby improving the performance of the entire circuit.

[0038] Compared with traditional heat dissipation methods, the design of the heat dissipation substrate is more compact, which helps to reduce the size and weight of the circuit, improving the portability and maintainability of the device. The heat dissipation substrate is usually made of high thermal conductivity materials such as aluminum, copper, or composite materials. These materials have good heat conduction performance and can quickly conduct heat to other heat dissipation devices.

[0039] The design of the heat dissipation substrate needs to consider multiple factors, including the contact method with electronic components, the optimization of the heat conduction path, and the increase of the heat dissipation area. Some heat dissipation substrates also use thermal conductive adhesives or thermal pads to improve the heat conduction efficiency.

[0040] The heat dissipation substrate and the heat sink may be connected by means such as thermal grease, welding, sintering, etc. to reduce the thermal resistance and improve the heat conduction efficiency.

[0041] In the preparation process of an existing heat dissipation substrate, first, diamond particles are cleaned with deionized water, then immersed in a 10% NaOH solution and boiled. After magnetic stirring for 30 minutes, they are taken out and cleaned with deionized water. Then, the degreased diamond particles are put into a 30% HNO3 solution and boiled. At the same time, after magnetic stirring for 30 minutes, they are cleaned with deionized water and dried. Finally, they are ultrasonically cleaned with acetone solution for 15 minutes and dried to obtain diamond particles with degreased and roughened surfaces. The diamond particles with degreased and roughened surfaces having an average particle size of 100 μm to 120 μm and molybdenum powder with an average particle size of 45 μm are mechanically mixed at a molar ratio of 10:1. Specifically, mechanical mixing is carried out by ball milling in a stainless steel ball milling tank at 250 rpm for 3 hours. Then, the uniformly mixed powder is loaded into an alumina crucible containing a chloride mixture. Specifically, the chloride mixture is obtained by grinding in an agate mortar for 30 minutes with a molar ratio of NaCl:KCl of 1:1. Then, the alumina crucible is placed in a tube furnace and heated to 1050 °C in an argon atmosphere and held for 15 minutes. After cooling to room temperature and taking out, diamond particles with molybdenum carbide coatings on their surfaces are obtained.

[0042] Then, the diamond particles with molybdenum carbide coatings on their surfaces are uniformly mixed with high-purity electrolytic copper powder (99.995%) having an average particle size of 45 μm at a volume content of 60% of the total volume. At room temperature, pre-pressing is carried out at a pressure of 500 MPa to obtain a green compact with a relative density of 80%. Then, please refer to Figure 1 , first, a layer of spherical copper powder 1 with a particle size of 20 μm is laid flat in a mold with a thickness of 0.5 mm. Subsequently, a copper plate 3 with a thickness of 2 mm and through holes is placed above the spherical copper powder 1. Then, the above-prepared green compact 2 is embedded in the through holes of the copper plate 3, and the green compact 2 is flush with the surface of the copper plate 3. Then, spherical copper powder 1 with a thickness of 2 mm is laid on the top.

[0043] Finally, vacuum hot pressing sintering is carried out. The sintering temperature is 950 °C, the holding time is 60 minutes, the sintering pressure is 70 MPa, and the vacuum degree is 10 -2 Pa. After cooling to room temperature, a heat dissipation substrate is obtained.

[0044] It is not difficult to see that for the heat dissipation substrate obtained by the above method, the upper and lower copper layers are sintered from copper powder and are not tightly combined with the middle copper-diamond composite layer, resulting in insufficient firmness of the heat dissipation substrate and being unable to meet the needs of actual applications.

[0045] To facilitate the understanding of this application, the following first introduces the relevant concepts involved in this application:

[0046] Annealing: Annealing is a metal heat treatment process. Specifically, it refers to the process of slowly heating a metal or alloy to a certain temperature, maintaining it for a sufficient time, and then cooling it at an appropriate speed. This process is not only applicable to metal materials but can also be applied to non-metal materials. Through annealing treatment, the hardness of the metal material can be reduced, thereby improving its machinability. Annealing helps to stabilize the size of the material and reduce the tendency of deformation and cracking caused by residual stresses generated during the processing. Annealing can adjust the microstructure of the material, eliminate structural defects by refining the grains, and improve the performance of the material. Annealing treatment can make the internal structure and composition of the material more uniform, providing a good foundation for subsequent processing or heat treatment.

[0047] Magnetron sputtering: Magnetron sputtering is a sputtering coating method that uses a magnetic field to confine the movement of electrons near the target surface and is a sputtering technology controlled by a magnetic field. In magnetron sputtering, through the interaction of the magnetic field and the electric field, electrons move in a spiral near the target surface, thereby increasing the probability of electrons colliding with argon gas to generate ions. The generated ions hit the target surface under the action of the electric field, and then the target material is sputtered. Among the sputtered particles, neutral target atoms or molecules are deposited on the substrate to form a thin film.

[0048] Vacuum brazing process: Vacuum brazing refers to the process of heating and brazing workpieces in a vacuum chamber. This process is mainly used for welding products with high quality requirements and materials that are prone to oxidation. The advantage of vacuum brazing is that it can eliminate oxidation and contamination during the welding process, provide cleaner and more precise welded joints, and is applicable to the welding of various metal and non-metal materials at the same time.

[0049] Active filler metal: Active filler metal refers to a type of filler metal that, during the brazing process, improves the wettability of the filler metal on the surface of specific materials by adding active elements. During the brazing process of this filler metal, the active elements will chemically react with the material surface to form a reaction layer that can be wetted by the liquid filler metal, thereby achieving effective connection between materials.

[0050] Please refer to Figure 2 , Figure 1 which is a cross-sectional view of the copper diamond heat dissipation substrate in this application. As Figure 2 shown, the copper diamond heat dissipation substrate in this application includes a copper diamond composite layer 1, a first metal layer 2, and a second metal layer 3. Among them, the copper diamond composite layer 1 includes a copper diamond material 11 and a metal frame 12. The copper diamond material 11 is disposed in the through holes of the metal frame 12. The first metal layer 2 is disposed on the upper layer of the copper diamond composite layer 1, and the second metal layer 3 is disposed on the lower layer of the copper diamond composite layer 1. The first metal layer 2 is fixedly connected to the copper diamond composite layer 1 through a first solder layer 4, and the second metal layer 3 is fixedly connected to the copper diamond composite layer through a second solder layer 5.

[0051] Please refer to Figure 3, Figure 3 This is an assembly schematic diagram of the copper diamond heat dissipation substrate in the present application. The copper diamond material 11 can be disposed in the through hole 121 of the metal frame 12, thereby obtaining the copper diamond composite layer 1. The upper and lower surfaces of the copper diamond composite layer 1 are respectively connected to the first metal layer 2 and the second metal layer 3 through solder layers (not shown in the figure), thereby obtaining the copper diamond heat dissipation substrate.

[0052] Please refer to Figure 4 , Figure 4 This is an assembly schematic diagram of the copper diamond composite layer in the present application. As Figure 4 shown, the through hole of the metal frame 12 is set to match the outer dimension of the copper diamond material 11, and the thickness of the metal frame 12 matches the thickness of the copper diamond material 11. Therefore, assembling the copper diamond material 11 into the through hole of the metal frame 12 can prevent the copper diamond material 11 from moving, improving the stability of the copper diamond heat dissipation substrate.

[0053] In a possible implementation manner, the material of the first metal layer 2 can be copper, aluminum, copper alloy or aluminum alloy, and the material of the second metal layer 3 can also be copper, aluminum, copper alloy or aluminum alloy. Among them, the material of the first metal layer 2 can be the same as or different from the material of the second metal layer 3, and specific details are not limited here. In addition, the material of the first solder layer 4 includes at least two elements among copper, tin, silver, titanium, nickel and chromium, and the material of the second solder layer 5 can also include at least two elements among copper, tin, silver, titanium, nickel and chromium. Among them, the material of the first solder layer 4 can be the same as or different from the material of the second solder layer 5, and specific details are not limited here.

[0054] The above introduced the structure of the copper diamond heat dissipation substrate in the present application. Next, the preparation method of the above copper diamond heat dissipation substrate will be introduced:

[0055] The preparation method of the copper diamond heat dissipation substrate in the present application can be divided into two stages: the preparation of the copper diamond material and the preparation of the copper diamond heat dissipation substrate.

[0056] In the stage of preparing the copper diamond material, mainly the diamond particles are metallized, that is, a metallized layer is deposited on the diamond particles.

[0057] The metallized layer of diamond refers to a layer of metal, alloy, metal carbide layer or a mixed layer of them formed on the diamond surface by physical or chemical methods. This metallized layer endows the diamond surface with metal properties, thereby improving the bonding ability and wetting performance between the diamond and other materials (especially the metal matrix), and providing a certain protection for the diamond surface.

[0058] The metallization layer plays the role of a "bonding bridge" between the diamond and the metal matrix, firmly bonding the two together and enhancing the bonding strength between them.

[0059] The metallization layer improves the wetting performance between the diamond and the metal matrix, making it easier to form a uniform interface during the preparation of the composite material, thereby enhancing the overall performance of the composite material.

[0060] The metallization layer can fill internal defects such as pores and microcracks on the surface of the diamond, maximizing the integrity of the diamond particles. During processes such as high-temperature sintering, the metallization layer can isolate and protect the diamond from oxidation, preventing it from undergoing graphitization transformation and corrosion by other chemical reactions. The metallization layer of the diamond includes one or more elements such as nickel, niobium, tantalum, titanium, cobalt, tungsten, molybdenum, chromium, etc., and the thickness of the metallization layer can be 0.1 - 3 μm.

[0061] Subsequently, the metallized diamond particles are thoroughly and evenly mixed with copper powder, and the diamond particles and copper powder are bonded through hot pressing sintering or plasma sintering processes to obtain copper diamond materials.

[0062] Hot sintering is the phenomenon or process that occurs when powders or powder compacts are heated under suitable temperature and atmosphere conditions. The result of sintering is the bonding between particles, an increase in the strength of the green body, generally accompanied by densification and metallurgical reactions. Hot sintering is a traditional sintering method with mature technology, applicable to the sintering of various materials such as ceramics, metals, composite materials, etc. The sintering process is relatively long, and it is necessary to control the sintering temperature and atmosphere. Spark plasma sintering is a new type of rapid sintering technology. It loads metal powders, etc. into a mold made of materials such as graphite, and applies a specific sintering power supply and pressing pressure to the sintering powder by using upper and lower punches and energized electrodes, and completes the process of producing high-performance materials through discharge activation, thermoplastic deformation, and cooling.

[0063] Spark plasma sintering features rapid heating and rapid cooling, which can significantly shorten the sintering cycle. By controlling sintering parameters such as pulsed current and pressing pressure, precise control of the microstructure of the sintered body can be achieved. Compared with traditional sintering methods, spark plasma sintering has higher energy utilization efficiency and lower energy consumption.

[0064] Spark plasma sintering can be used to prepare various high-performance materials such as metals, ceramics, composite materials, etc., especially showing great superiority in the preparation of new materials such as nanomaterials and gradient functional materials. Among them, hot pressing sintering uses a vacuum degree of 10 -1- 10 -3Under the protection of Pa or inert gas, the pressure is 10 - 60 MPa, the heat preservation temperature is 800 - 1100 °C, and the heat preservation time is 10 - 240 min. For spark plasma sintering, the pressure is 10 - 60 MPa, the temperature is 600 - 1000 °C, the heat preservation time is 5 - 30 min, and the vacuum degree is 10 -1 -10 -3 Pa.

[0065] In the preparation stage of the copper diamond heat dissipation substrate, mainly cut out holes in the center of the metal sheet to obtain a metal frame. The material of the metal sheet can be one or several of copper, aluminum, copper alloy, and aluminum alloy.

[0066] The hole size of the metal frame is equivalent to the outer dimension of the copper diamond material, and the thickness is also equivalent. Then, an active brazing filler metal is coated on the surface of the metal frame and the metal sheet. The active brazing filler metal includes at least two elements among copper, tin, silver, titanium, nickel, and chromium.

[0067] Place the copper diamond material into the metal frame to obtain a copper diamond composite layer. Assemble the metal sheets on the upper and lower sides of the copper diamond composite layer. Finally, put the assembled sample into a brazing furnace. Under certain temperature and pressure, the active brazing filler metal forms a first solder layer and a second solder layer, thereby obtaining the copper diamond heat dissipation substrate with a multi-layer structure in this application, where the vacuum degree is 10 -1 -10 -3 Pa, the pressure is 1 - 100 MPa, the heat preservation temperature is 600 - 1000 °C, and the heat preservation time is 10 - 90 min.

[0068] The following introduces several specific processes for preparing the copper diamond heat dissipation substrate:

[0069] Preparation process one:

[0070] Preparation stage of the copper diamond material:

[0071] Take diamond particles with a particle size of about 200 μm (70 / 80 mesh), and deposit tungsten (W) metal layers on these diamond particles. Specifically, the magnetron sputtering power is 150 w, the deposition time is 30 min, and diamond particles with a metal layer thickness of about 0.1 μm are obtained.

[0072] Place the metallized diamond particles in a vacuum annealing at 1000 °C for 60 min to obtain a sufficiently reacted W metal layer.

[0073] Subsequently, mix the diamond particles with copper powder with a particle size of about 50 μm at a volume ratio of diamond particles: copper powder of 55:45 to obtain a mixed powder.

[0074] Spread and compact the uniformly mixed powder in a graphite mold, and then place the graphite mold in a high-temperature vacuum hot press furnace. First, evacuate the vacuum degree to 1×10-3 Below Pa, first heat it at a rate of 10 °C / min to 600 °C, hold for 30 min, then heat it at a rate of 5 °C / min to 1000 °C, with a holding time of 180 min, and the pressure during holding is 50 MPa; cool it at a rate of 5 °C / min to 700 °C, and then cool it in the furnace.

[0075] After cooling, demold and sample to prepare a square copper diamond material with dimensions of 24×36×1.0 mm. The thermal conductivity of the prepared copper diamond material is 612 W / mK.

[0076] Preparation stage of the copper diamond heat dissipation substrate:

[0077] Obtain a pure copper plate with an outer dimension of 140×100×1 mm and a square hole with a size of 24.1×36.1 mm at the center position through laser cutting.

[0078] Place the 24×36×1.0 mm copper diamond material prepared by the above sintering into the 24.1×36.1 mm square hole to obtain a copper diamond composite layer.

[0079] In addition, cover each of the upper and lower surfaces of the copper diamond composite layer with a copper foil with a size of 140×100×0.1 mm coated with active solder (solder). Place the assembled sample in a graphite mold and use a vacuum brazing process. First, evacuate the vacuum to below 1×10 -3 Pa, set the pressure to 10 MPa, the holding temperature to 900 °C, hold for 30 min, and the active solder forms the first solder layer and the second solder layer, finally obtaining a copper diamond heat dissipation substrate with dimensions of 140×100×1.2 mm.

[0080] As a comparative example, the process of preparing another copper diamond heat dissipation substrate is introduced below:

[0081] Preparation stage of the copper diamond material:

[0082] Take diamond particles with a particle size of about 200 μm (70 / 80 mesh), and deposit a tungsten (W) metal layer on these diamond particles. Specifically, the magnetron sputtering power is 150 w, the deposition time is 30 min, and diamond particles with a metal layer thickness of about 1.5 μm are obtained.

[0083] Then place the metallized diamond particles in a vacuum at 1000 °C and anneal for 60 min to obtain a well-reacted W metal layer.

[0084] Subsequently, mix the diamond particles with copper powder with a particle size of about 50 μm at a volume ratio of diamond particles: copper powder of 55:45 to obtain a mixed powder.

[0085] The mixed powder was placed in a graphite mold, flattened and compacted, and then the graphite mold was placed in a high-temperature vacuum hot press furnace with a pre-vacuum degree of 1×10 -3 Pa, first increase the temperature to 600℃ at a rate of 10℃ / min, keep it warm for 30min, then increase the temperature to 1000℃ at a rate of 5℃ / min, keep it warm for 180min, and the pressure during the insulation is 50MPa; cool down to 700℃ at 5℃ / min, and then cool with the furnace.

[0086] After cooling, the sample was demolded and a square copper diamond material with a size of 24×36×1.0 mm was prepared. The thermal conductivity of the prepared copper diamond material was 612 W / mK.

[0087] Preparation stages of copper diamond heat dissipation substrate:

[0088] A pure copper plate with an outer dimension of 140×100×1 mm and a square hole of 24.1×36.1 mm at the center was obtained by laser cutting.

[0089] The 24×36×1.0 mm copper diamond material prepared by sintering was placed in a 24.1×36.1 mm square hole to obtain a copper diamond composite layer. In addition, a layer of copper foil coated with active brazing material (solder) with a size of 140×100×0.1 mm was coated on the upper and lower surfaces of the copper diamond composite layer. The assembled sample was placed in a graphite mold and vacuum brazed using a vacuum brazing process. The vacuum degree was pre-drawn to 1×10 -3 Pa, the pressure was set to 10 MPa, the insulation temperature was 900 °C, and the insulation was carried out for 30 min, and finally a copper diamond heat dissipation substrate with a size of 140 × 100 × 1.2 mm was obtained.

[0090] In this comparative example, the W metal layer deposited on the surface of the diamond particles has a thickness of 1.5 um. The copper diamond material prepared under this condition has a large thermal resistance due to the too thick metal layer, and the thermal conductivity is not higher than that of copper.

[0091] Preparation process 2:

[0092] Preparation stages of copper diamond materials:

[0093] Diamond particles with a particle size of about 300 μm (50 / 60 mesh) were taken and a W metal layer was deposited on the diamond particles. The magnetron sputtering power was 150 W and the deposition time was 45 min. Diamond particles with a metal layer thickness of about 0.15 μm were obtained.

[0094] The metallized diamond particles were vacuum annealed at 1000° C. for 60 min to obtain a fully reacted W metal layer.

[0095] Subsequently, diamond particles were mixed with copper powder having a particle size of about 100 μm in a volume ratio of diamond particles: copper powder of 50:50 to obtain a mixed powder. The uniformly mixed powder was placed in a graphite mold, flattened, and compacted. Subsequently, the mold was placed in a high-temperature vacuum hot press furnace, and the vacuum was first pumped to below 1×10 -3 Pa. First, it was heated to 600 °C at a rate of 10 °C / min and held for 30 min. Subsequently, it was heated to 1000 °C at a rate of 5 °C / min, and the holding time was 90 min. The pressure during holding was 55 MPa.

[0096] It was cooled to 700 °C at a rate of 5 °C / min and then cooled with the furnace; after cooling, the mold was removed and samples were taken to prepare square sheet copper diamond materials with dimensions of 24×36×1.1 mm. The thermal conductivity of the prepared copper diamond materials was 636 W / mK.

[0097] Preparation stage of the copper diamond heat dissipation substrate:

[0098] A pure copper plate with an outer dimension of 140×100×1.1 mm and a square hole with a size of 24.2×36.2 mm at the center position was obtained by laser cutting.

[0099] The 24×36×1.1 mm copper diamond material prepared by the above sintering was placed in the 24×36 mm square hole to obtain a copper diamond composite layer.

[0100] In addition, a copper foil coated with active solder with a size of 140×100×0.05 mm was covered on each of the upper and lower surfaces of the copper diamond composite layer. The assembled sample was placed in a graphite mold, and a vacuum brazing process was used. The vacuum was first pumped to below 1×10 -3 Pa, the pressure was set to 15 MPa, the holding temperature was 950 °C, and the holding time was 45 min. Finally, a copper / diamond heat dissipation substrate with dimensions of 140×100×1.2 mm was obtained.

[0101] As a comparative example, the process of preparing another copper diamond heat dissipation substrate is introduced below:

[0102] Preparation stage of the copper diamond material:

[0103] Diamond particles with a particle size of about 300 μm (50 / 60 mesh) were taken, and a W metal layer was deposited on these diamond particles. The magnetron sputtering power was 150 w, and the deposition time was 45 min to obtain diamond particles with a metal layer thickness of about 0.15 μm.

[0104] The metallized diamond particles were then vacuum annealed at 1000 °C for 60 min to obtain a fully reacted W metal layer.

[0105] Subsequently, diamond particles were mixed with copper powder having a particle size of about 100 μm at a volume ratio of diamond particles:copper powder of 50:50 to obtain a mixed powder, and the uniformly mixed powder was placed in a graphite mold, paved and compacted.

[0106] Subsequently, the mold was placed in a high-temperature vacuum hot press furnace, and the vacuum was first pumped to below 1×10 -3 Pa. First, it was heated to 600 °C at a rate of 10 °C / min and held for 30 min, then heated to 1000 °C at a rate of 5 °C / min and held for 90 min, and the pressure during holding was 30 MPa. It was cooled to 700 °C at a rate of 5 °C / min and then cooled with the furnace; after cooling, the mold was removed and samples were taken to prepare a square copper-diamond material with dimensions of 24×36×1.1 mm. The thermal conductivity of the prepared copper-diamond material was 636 W / mK.

[0107] Preparation stage of the copper-diamond heat dissipation substrate:

[0108] A pure copper plate with an outer dimension of 140×100×1.1 mm and a square hole of 24.2×36.2 mm at the center was obtained by laser cutting.

[0109] The 24×36×1.1 mm copper-diamond material prepared by sintering above was placed in the 24×36 mm square hole to obtain a copper-diamond composite layer.

[0110] In addition, a copper foil coated with active solder with dimensions of 140×100×0.05 mm was covered on each of the upper and lower surfaces of the copper-diamond composite layer. The assembled sample was placed in a graphite mold, and a vacuum brazing process was used. The vacuum was first pumped to below 1×10 -3 Pa, the pressure was set to 15 MPa, the holding temperature was 950 °C, and the holding time was 45 min. Finally, a copper / diamond heat dissipation substrate with dimensions of 140×100×1.2 mm was obtained.

[0111] In this comparative example, the high-temperature vacuum hot pressing process used a pressure of 30 MPa. Under this condition, the copper-diamond material prepared had an excessive density, and its thermal conductivity was not higher than that of copper.

[0112] Preparation process three:

[0113] Preparation stage of the copper-diamond material:

[0114] Diamond particles with a particle size of about 400 μm (40 / 45 mesh) were taken to deposit a W metal layer. The magnetron sputtering power was 150 w, and the deposition time was 60 min to obtain diamond particles with a metal layer thickness of about 0.2 μm.

[0115] Then, the metallized diamond particles were vacuum annealed at 1000 °C for 60 min to obtain a W metal layer with sufficient reaction.

[0116] Subsequently, diamond particles and copper powder with a particle size of about 150 μm were mixed at a volume ratio of diamond particles: copper powder of 45:55 to obtain a mixed powder.

[0117] The uniformly mixed powder was placed in a graphite mold, paved and compacted. Subsequently, the mold was placed in a high-temperature vacuum hot press furnace, and the vacuum was first pumped to below 1×10 -3 Pa. It was first heated to 600 °C at a rate of 10 °C / min and held for 30 min. Subsequently, it was heated to 1000 °C at a rate of 5 °C / min, and the holding time was 60 min. The pressure during holding was 60 MPa. It was cooled to 700 °C at a rate of 5 °C / min and then cooled with the furnace.

[0118] After cooling, the mold was removed and samples were prepared to obtain square copper diamond materials with dimensions of 24×36×0.8 mm. The thermal conductivity of the prepared copper diamond materials was 650 W / mK.

[0119] Preparation stage of the copper diamond heat dissipation substrate:

[0120] A pure copper plate with an outer dimension of 140×100×0.8 mm and a square hole with a size of 24.3×36.3 mm at the center position was obtained through laser cutting.

[0121] The 24×36×0.8 mm copper diamond material prepared by the above sintering was placed in the 24.3×36.3 square hole to obtain a copper diamond composite layer.

[0122] In addition, a copper foil coated with active solder with a size of 140×100×0.2 mm was covered on each of the upper and lower surfaces of the copper diamond composite layer. The assembled sample was placed in a graphite mold and a vacuum brazing process was used. The vacuum was first pumped to 1×10 - 3 Pa below, the pressure was set to 20 MPa, the holding temperature was 900 °C, and the holding time was 60 min. Finally, a copper diamond heat dissipation substrate with dimensions of 140×100×1.2 mm was obtained.

[0123] As a comparative example, the process of preparing another copper diamond heat dissipation substrate is introduced below:

[0124] Preparation stage of the copper diamond material:

[0125] Diamond particles with a particle size of about 400 μm (40 / 45 mesh) were taken to deposit a W metal layer. The magnetron sputtering power was 150 w and the deposition time was 60 min to obtain diamond particles with a metal layer thickness of about 0.2 μm.

[0126] The metallized diamond particles are then annealed in vacuum at 1000 °C for 60 min to obtain a well-reacted W metal layer.

[0127] Subsequently, the diamond particles are mixed with copper powder with a particle size of about 150 μm in a volume ratio of diamond particles: copper powder of 45:55 to obtain a mixed powder.

[0128] The uniformly mixed powder is placed in a graphite mold, paved and compacted. Then the mold is placed in a high-temperature vacuum hot press furnace, and the vacuum is first pumped to below 1×10 -3 Pa. First, it is heated to 600 °C at a rate of 10 °C / min and held for 30 min. Then it is heated to 1000 °C at a rate of 5 °C / min, and the holding time is 60 min. The pressure during holding is 60 MPa. It is cooled to 700 °C at a rate of 5 °C / min and then cooled with the furnace. After cooling, the mold is demolded and samples are taken to prepare a square copper-diamond material with dimensions of 24×36×0.8 mm. The thermal conductivity of the prepared copper-diamond material is 650 W / mK.

[0129] Preparation stage of the copper-diamond heat dissipation substrate:

[0130] A pure copper plate with an outer dimension of 140×100×0.8 mm and a square hole with a size of 24.3×36.3 mm at the center position is obtained by laser cutting.

[0131] The 24×36×0.8 mm copper-diamond material prepared by the above sintering is placed in the 24.3×36.3 square hole to obtain a copper-diamond composite layer.

[0132] In addition, a copper foil coated with active brazing filler metal with dimensions of 140×100×0.2 mm is covered on each of the upper and lower surfaces of the copper-diamond composite layer. The assembled sample is placed in a graphite mold and a vacuum brazing process is used. The vacuum is first pumped to below 1×10 - 3 Pa, the pressure is set to 20 MPa, the holding temperature is 700 °C, and the holding time is 60 min. Finally, a copper-diamond heat dissipation substrate with dimensions of 140×100×1.2 mm is obtained.

[0133] In this comparative example, the vacuum brazing process uses a holding temperature of 700 °C. Under this condition, since the holding temperature does not reach the brazing temperature of the active brazing filler metal, the copper foil is separated from the copper-diamond composite layer.

[0134] In another possible implementation, in order to enable the copper-diamond heat dissipation substrate to adapt to different installation environments and broaden the application scenarios of the heat dissipation substrate, after the copper-diamond heat dissipation substrate is prepared by the above method, the copper-diamond heat dissipation substrate can also be subjected to stamping treatment.

[0135] Specifically, please refer toFigure 5 During stamping, the stationary area is the area where the copper diamond material is located, that is, the area within the dashed line frame in the figure. The stressed area is the area outside the dashed line frame. This part of the area deforms under stress to obtain the required product shape.

[0136] It should be noted that in actual implementation, the stationary area can be freely set, only need to enclose the copper diamond material, and the area of the stationary area can be greater than or equal to the area of the copper diamond material.

[0137] In addition, the shape of the stationary area can match or not match the shape of the copper diamond material. For example, in addition to being square, it can also be replaced with other shapes, such as circular.

[0138] Please refer to Figure 6 , Figure 6 shows a comparison of the copper diamond heat dissipation substrate before and after stamping. For the sake of simplicity of description, only the position of the copper diamond material 11 is particularly shown in the figure, and the rest of the structure is similar to that described above and will not be listed one by one. As Figure 6 shown, after stamping, the copper diamond heat dissipation substrate forms a boss area 61, a flat edge 62, and a cavity 63 corresponding to the boss area 61. The copper diamond material 11 is located in the boss area 61. It should be understood that the boss area 61 corresponds to the aforementioned stationary area.

[0139] In a possible implementation, in order to avoid cracking due to stress concentration during stamping, the edge of the boss area 61 can be set as a rounded corner.

[0140] Please refer to Figure 7 , Figure 7 is a top view of the copper diamond substrate after stamping, and the boss area 61 and the flat edge 62 can be seen. In another possible implementation, stiffeners 611 can also be provided on the flat edge 62. Stiffeners are also known as reinforcing ribs or strengthening ribs, and are a kind of shape-like design formed on stamped parts through specific process methods (such as bending, pressing, stamping, etc.). It is usually placed at key parts such as the corners, edges, and pressing plates of stamped parts to play a role in strengthening and supporting.

[0141] Stiffeners can significantly improve the strength and rigidity of stamped parts without increasing the wall thickness of the product, thereby saving material usage, reducing weight, and lowering costs. Stiffeners can also prevent stamped parts from being overly bent or distorted when subjected to external forces, ensuring the stability and reliability of the product.

[0142] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0143] The above-described embodiments merely represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A copper diamond heat dissipation substrate, comprising a copper diamond composite layer, a first metal layer, and a second metal layer. The copper diamond composite layer includes copper diamond material and a metal frame. The copper diamond material is disposed in the through hole of the metal frame. The first metal layer is disposed on the upper layer of the copper diamond composite layer, and the second metal layer is disposed on the lower layer of the copper diamond composite layer. It is characterized in that, The first metal layer is fixedly connected to the copper-diamond composite layer through a first solder layer, and the second metal layer is fixedly connected to the copper-diamond composite layer through a second solder layer.

2. The copper diamond heat dissipation substrate according to claim 1, wherein The copper-diamond heat dissipation substrate includes a boss region and a cavity corresponding to the boss region.

3. The copper diamond heat dissipation substrate according to claim 2, wherein The copper-diamond material is located within the boss region.

4. The copper diamond heat dissipation substrate according to claim 3, wherein The edge of the boss region is rounded.

5. The copper diamond heat dissipation substrate according to any one of claims 1 to 4, characterized in that The material of the first metal layer is copper, aluminum, copper alloy or aluminum alloy.

6. The copper diamond heat dissipation substrate according to claim 5, wherein, The material of the second metal layer is copper, aluminum, copper alloy or aluminum alloy.

7. The copper diamond heat dissipation substrate according to claim 6, wherein The first solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium.

8. The copper diamond heat dissipation substrate according to claim 7, wherein The second solder layer includes at least two elements among copper, tin, silver, titanium, nickel and chromium.

9. The copper diamond heat dissipation substrate according to any one of claims 1 to 8, characterized in that, The thickness of the copper-diamond material is the same as the thickness of the metal frame.

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