Heat dissipation substrate, and preparation method therefor and use thereof

Abstract

Disclosed in the present application are a heat dissipation substrate, and a preparation method therefor and the use thereof. The heat dissipation substrate provided in the present application comprises a metal substrate body. At least 75% of the area of the metal substrate body is provided with a three-layer structure, and the three-layer structure comprises an upper surface metal layer, a composite thermal conductive material layer and a lower surface metal layer, which are sequentially arranged, wherein the composite thermal conductive material layer is a dense sintered body. In the dense sintered body, a metal acts as a framework, and diamond particles act as a reinforcement phase. In the heat dissipation substrate provided in the present application, the composite thermal conductive material layer is arranged in part of the region inside the metal substrate body, so as to limit the direct contact between the composite thermal conductive material and the outside, such that more heat is concentrated inside the composite thermal conductive material, and the heat is then quickly dissipated to the surrounding environment, thereby improving the heat dissipation efficiency. The prepared heat dissipation substrate has a good thermal conductivity and heat dissipation performance, and can be used to manufacture a heat dissipation assembly for an electronic device, and the manufactured heat dissipation assembly for an electronic device is widely applied to efficient heat dissipation and heat management of a variety of power components.

Description

A heat dissipation substrate, its preparation method and application Technical fields:

[0001] This application relates to the field of heat dissipation substrate technology, and more specifically, to a heat dissipation substrate, its preparation method, and its application. Background technology:

[0002] As power devices rapidly evolve towards miniaturization and multifunctionality, chip sizes have increased from 90nm in 2004 to 28nm in 2011 and then to 2nm in 2004. This has led to an exponential increase in heat generated per unit area, resulting in severe heat dissipation problems for power devices. IGBT power devices generate a significant amount of heat during operation. If this heat cannot be dissipated effectively and promptly, the accumulated heat will cause performance degradation or even damage to the device. Data shows that within a certain range, for every 10°C increase in temperature, the performance of electronic devices decreases by more than 50%. Therefore, heat dissipation plays a crucial role in power devices. The heat transfer path for power devices is as follows: chip / diode → under-chip bonding layer → DBC copper layer → DBC ceramic layer → DBC copper layer → substrate bonding layer → substrate → thermally conductive silicone → heat sink → external environment. The heat dissipation substrate, as the core component of the heat dissipation structure, has a decisive impact on the performance of the power module.

[0003] Copper-diamond heat sink substrates are high-performance composite heat dissipation materials that combine the high thermal conductivity of copper with the low coefficient of thermal expansion and high hardness of diamond, meeting the demands of modern electronic devices for efficient heat dissipation and thermal management. However, the poor wettability of diamond with copper is one of the challenges in the preparation of diamond / copper heat sink materials. Currently, surface modification of diamond is often used to improve its wettability, but this modification increases interfacial thermal resistance, affecting the thermal conductivity and coefficient of thermal expansion of the diamond / copper heat sink material, thus limiting its industrial application. Summary of the Invention:

[0004] The purpose of this application is to overcome the defects of the prior art and provide a heat dissipation substrate, its preparation method and application.

[0005] The technical problem solved by this application is achieved by the following technical solution.

[0006] This application provides a heat dissipation substrate, including a metal substrate body. At least 75% of the area of ​​the metal substrate body has a three-layer structure. The three-layer structure includes an upper surface metal layer, a composite thermally conductive material layer and a lower surface metal layer arranged sequentially. The composite thermally conductive material layer is a dense sintered body with metal as the skeleton and diamond particles as the reinforcing phase.

[0007] In some embodiments of this application, at least 85% of the area of ​​the metal substrate body has a three-layer structure.

[0008] In some embodiments of this application, the lower surface of the metal substrate body is further provided with a plurality of heat dissipation fins, which are shovel-tooth fins, needle-shaped fins or columnar fins, wherein: the diameter of the needle-shaped fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm, and the thickness of the shovel-tooth fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm.

[0009] In some embodiments of this application, both the metal substrate body and the cover plate are made of metal, specifically copper or aluminum.

[0010] This application also provides a method for preparing the above-mentioned heat dissipation substrate, comprising the following steps: providing a metal substrate body, processing grooves on the metal substrate body, filling the grooves with composite thermally conductive material, and then covering the grooves with a cover plate matching the grooves to obtain a green blank; hot pressing and sintering the green blank to obtain a cooked blank, and grinding the surface of the cooked blank.

[0011] In some embodiments of this application, the fitting clearance between the cover plate and the groove is 0.01 mm to 0.1 mm; the cover plate is also provided with micropores, the diameter of which is <0.3 mm.

[0012] In some embodiments of this application, the preparation of the green embryo includes: filling a groove with a composite thermally conductive material, ultrasonically treating it, and then covering it with a cover plate, with the upper surface of the cover plate slightly higher than the height of the groove, to obtain the green embryo, wherein:

[0013] The composite thermally conductive material includes diamond particles and metal powder, with the diamond particle content ≥60wt%; the particle size of the diamond particles is 300μm~800μm; and the particle size of the metal powder is 5μm~20μm.

[0014] The metal powder includes at least one of copper powder, aluminum powder, tungsten copper powder, and molybdenum copper powder. Diamond particles can be replaced with ceramic powder, which is selected from at least one of boron nitride powder, aluminum nitride powder, silicon carbide powder, and silicon nitride powder.

[0015] In some embodiments of this application, hot pressing sintering includes: placing the green blank in a hot pressing apparatus and evacuating the hot pressing apparatus to a vacuum level of 5*10. -2 Below Pa, the temperature is increased to 600℃ to 1150℃ at a rate of 5℃ / min to 25℃ / min, held for 10min to 60min, and the pressure head is maintained at 1MPa to 10MPa for 5min to 60min to obtain a cooked embryo.

[0016] In some embodiments of this application, surface grinding includes: removing excess metal layers from the surface of a hot-pressed sintered blank by surface grinding, such that the thickness of the upper surface metal layer after grinding is 0.05 mm to 0.5 mm and the thickness of the lower surface metal layer is 2.5 mm to 3 mm, thereby obtaining a master blank.

[0017] In some embodiments of this application, the method further includes: after hot pressing and sintering the green blank and grinding the surface of the finished blank, heat dissipation fins are processed on the lower surface of the mother blank using CNC technology to obtain a heat dissipation substrate, wherein: the heat dissipation substrate using diamond particles and copper powder composite as composite thermal conductive material has a thermal conductivity of 650W / m*k to 900W / m*k, and the heat dissipation substrate using diamond particles and aluminum powder composite as composite thermal conductive material has a thermal conductivity of 500W / m*k to 750W / m*k.

[0018] This application also provides the application of the above-described heat dissipation substrate or the heat dissipation substrate prepared by the above-described preparation method in the manufacture of heat dissipation components for electronic devices.

[0019] This application has the following beneficial effects:

[0020] This application provides a heat dissipation substrate, its fabrication method, and its application. The heat dissipation substrate provided in this application includes a metal substrate body, with at least 75% of the metal substrate body having a three-layer structure. The three-layer structure includes an upper surface metal layer, a composite thermally conductive material layer, and a lower surface metal layer sequentially disposed. The composite thermally conductive material layer is a dense sintered body, with metal as the skeleton and diamond particles as the reinforcing phase. In this application, by sealing the composite thermally conductive material within the metal substrate body, the use of adhesives is avoided, eliminating the defects caused by the decrease in thermal conductivity due to the use of adhesives. Furthermore, the composite thermally conductive material embedded inside the heat dissipation substrate allows more heat to concentrate inside the heat sink, effectively improving heat dissipation efficiency. This results in a heat dissipation substrate with good thermal conductivity and heat dissipation properties, enabling rapid heat dissipation and achieving fast and effective heat dissipation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 shows the SEM image of the metal powder;

[0023] Figure 2 shows the SEM image of the diamond particles;

[0024] Figure 3 is a front view of the substrate;

[0025] Figure 4 is a schematic diagram of the substrate and cover plate;

[0026] Figure 5 is a schematic diagram of the heat dissipation substrate;

[0027] Figure 6 shows one of the actual images of the heat dissipation substrate;

[0028] Figure 7 is the second physical image of the heat dissipation substrate. Detailed implementation method:

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] The following is a detailed description of a heat dissipation substrate, its preparation method, and its application provided in the embodiments of this application.

[0031] In a first aspect, embodiments of this application provide a heat dissipation substrate, including a metal substrate body, wherein at least 75% of the area of ​​the metal substrate body has a three-layer structure, the three-layer structure including an upper surface metal layer, a composite thermally conductive material layer and a lower surface metal layer arranged sequentially, the composite thermally conductive material layer being a dense sintered body, the dense sintered body having a metal skeleton and diamond particles as a reinforcing phase.

[0032] Currently, to improve the heat dissipation performance of heat dissipation substrates, the prepared composite thermally conductive material is typically coated or adhered to the metal substrate, or injected into grooves in the metal substrate using adhesive, followed by hot-pressing and sintering to fix the composite thermally conductive material within the grooves. These processes are not only cumbersome and costly, but also produce unsatisfactory heat dissipation results. Furthermore, the adhesive injection method heavily relies on the adhesive properties, which can affect the thermal resistance and coefficient of thermal expansion of the composite thermally conductive material, thus impacting its thermal conductivity.

[0033] To overcome the aforementioned problems in the prior art, this application provides a heat dissipation substrate in which a composite thermally conductive material layer is embedded in a portion of a metal substrate body. This composite thermally conductive material layer is a dense sintered body, with metal as the skeleton and diamond particles as the reinforcing phase. No adhesive is used in the composite thermally conductive material layer, ensuring that the thermal conductivity of the composite thermally conductive material is unaffected by adhesives and the external environment, thus facilitating excellent heat dissipation performance and significantly improving the heat dissipation effect of the heat dissipation substrate. Exemplarily, at least 75%, 80%, 85%, 90%, and 95% of the area of ​​the metal substrate body has a three-layer structure.

[0034] In some alternative implementations, at least 85% of the area of ​​the metal substrate body has a three-layer structure.

[0035] This application provides a heat dissipation substrate whose heat dissipation performance mainly depends on the three-layer structure disposed within the metal substrate body, especially the composite thermally conductive material layer in the three-layer structure. Therefore, increasing the area of ​​the region with the three-layer structure within the metal substrate body can improve the heat dissipation performance of the heat dissipation substrate.

[0036] In some alternative embodiments, the lower surface of the metal substrate body is further provided with a plurality of heat dissipation fins, which are shovel-tooth fins, needle-shaped fins or columnar needle fins, wherein: the diameter of the needle-shaped fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm, and the thickness of the shovel-tooth fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm.

[0037] This application provides a heat dissipation substrate, including a metal substrate body, in which a composite thermally conductive material layer formed by a composite thermally conductive material embedded inside has good thermal conductivity and heat dissipation. A heat dissipation path is also provided on its lower surface, which can enhance the thermal conductivity and heat dissipation performance of the heat dissipation substrate and achieve rapid and effective heat dissipation.

[0038] In some alternative embodiments, both the metal substrate body and the cover plate are made of copper or aluminum. Metal materials such as copper or aluminum have good heat dissipation properties, and using them as the material for the metal substrate body and cover plate can transfer heat from the power device to the outside and provide mechanical support for the power device.

[0039] Secondly, embodiments of this application also provide a method for preparing the above-mentioned heat dissipation substrate, comprising the following steps: providing a metal substrate body, processing grooves on the metal substrate body, filling the grooves with composite thermally conductive material, and then covering the grooves with a cover plate matching the grooves to obtain a green blank; hot pressing and sintering the green blank to obtain a cooked blank, and grinding the surface of the cooked blank.

[0040] This application provides a method for preparing the above-mentioned heat dissipation substrate, including the following steps: providing a metal substrate body, processing grooves on the metal substrate body, filling the grooves with composite thermally conductive material, and then covering the grooves with a cover plate, which can cover and seal the grooves to obtain a green blank. Then, the green blank is hot-pressed and sintered to obtain a cooked blank, and the surface of the cooked blank is ground. Hot-pressing and sintering can promote the fusion of metal and diamond, reduce porosity, and increase density, which is beneficial to improving the heat dissipation performance of the heat dissipation substrate, while surface grinding can improve the regularity and aesthetics of the heat dissipation substrate.

[0041] In some alternative embodiments, the fitting clearance between the cover plate and the groove is 0.01 mm to 0.1 mm;

[0042] The cover plate is also provided with micropores, the diameter of which is <0.3mm.

[0043] For example, the fitting gap between the cover plate and the groove can be 0.01mm, 0.05mm, 0.07mm, 0.09mm, 0.1mm and any other value between 0.01mm and 0.1mm, and the cover plate is provided with microholes, the diameter of which can be 0.1mm, 0.15mm, 0.2mm and 0.25mm.

[0044] This application provides a method for preparing a heat dissipation substrate. A composite thermally conductive material is embedded inside the heat dissipation substrate through the cooperation of a groove and a cover plate. The gap between the cover plate and the groove is 0.01mm to 0.1mm, which allows for a tighter fit between the cover plate and the metal substrate. It is worth noting that the shape of the groove is not limited; it can be triangular, quadrilateral, square, inverted trapezoidal, etc., as long as the dimensions of the groove and the cover plate match. Furthermore, micropores are provided on the cover plate to expel air from the groove and the gaps between the composite thermally conductive material filling the groove during the preparation of the heat dissipation substrate, improving the density of the composite thermally conductive material. The micropores close after subsequent hot pressing and sintering, forming a single, integrated heat dissipation substrate.

[0045] In some alternative embodiments, the preparation of the green embryo includes: filling a groove with a composite thermally conductive material, ultrasonically treating it, and then covering it with a cover plate, with the upper surface of the cover plate slightly higher than the height of the groove, to obtain the green embryo, wherein:

[0046] The composite thermally conductive material includes diamond particles and metal powder, with the diamond particle content ≥60wt%; the particle size of the diamond particles is 300μm~800μm; and the particle size of the metal powder is 5μm~20μm.

[0047] The metal powder includes at least one of copper powder, aluminum powder, tungsten copper powder, and molybdenum copper powder. Diamond particles can be replaced with ceramic powder, which is selected from at least one of boron nitride powder, aluminum nitride powder, silicon carbide powder, and silicon nitride powder.

[0048] For example, the particle size of the diamond particles can be 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, or any other value between 300μm and 800μm; the particle size of the metal powder can be 5μm, 10μm, 15μm, 20μm, or any other value between 5μm and 20μm; and the content of diamond particles in the mixed powder can be 60wt%, 65wt%, 70wt%, 80wt%, 90wt%, etc.

[0049] This application provides a method for preparing a heat dissipation substrate, comprising: filling a composite thermally conductive material into a groove in a metal substrate body. The composite thermally conductive material includes metal powder and diamond particles, wherein the content of diamond particles is controlled to be ≥60wt%. Diamond has an ultra-high thermal conductivity, reaching up to 2000W / m·K. Using diamond particles as a reinforcing phase is beneficial to improving the heat dissipation performance of the composite thermally conductive material. If the diamond particle content is too low, heat transfer mainly relies on the metal material, but the thermal conductivity of the metal material is much lower than that of diamond, resulting in a decrease in overall heat transfer efficiency. In addition, the particle size of the diamond particles used is controlled within the range of 300μm to 800μm. If the particle size of the diamond particles is too small, the heat transfer path is mainly dominated by the low thermal conductivity of the metal material, resulting in a decrease in the thermal conductivity of the heat dissipation substrate; if the particle size of the diamond particles is too large, the cost is high and the economic benefits are low.

[0050] After ultrasonic vibration, a mixture of diamond particles and metal powder is formed. The diamond particles are densely arranged, and the metal powder fills the gaps between the diamond particles. Ultrasonic treatment can improve the density of the composite thermally conductive material and reduce its porosity. A cover plate is then placed in a groove, with its upper surface slightly higher than the upper surface of the groove. During hot-pressing sintering, the cover plate is pressed into the groove, ensuring a tight fit between the cover plate and the inner wall of the groove. This ensures no gaps between the metal and diamond during hot pressing. Surface grinding is then performed to remove burrs and surface defects, resulting in a one-piece heat dissipation substrate. Testing shows that the thermal conductivity of the composite thermally conductive material prepared using the method provided in this application is significantly higher than that of commercially available metal and metal-based composite materials. The combination of metal and diamond not only solves the hardness and brittleness defects of diamond materials but also significantly improves the heat dissipation efficiency of the heat dissipation substrate. Furthermore, the one-piece molding of the composite thermally conductive material and the metal substrate reduces process complexity and manufacturing costs, and facilitates the development of thinner and miniaturized heat dissipation substrates, meeting the needs of modern electronic devices for efficient heat dissipation and thermal management.

[0051] In some alternative embodiments, hot pressing sintering includes: placing the green blank in a hot pressing apparatus and evacuating the hot pressing apparatus to a vacuum of 5*10. -2 Below Pa, the temperature is increased to 600℃ to 1150℃ at a rate of 5℃ / min to 25℃ / min, held for 10min to 60min, and the pressure head is maintained at 1MPa to 10MPa for 5min to 60min to obtain a cooked embryo.

[0052] For example, the heating rate during hot pressing sintering can be 5℃ / min, 10℃ / min, 15℃ / min, 20℃ / min, 25℃ / min, or any other value between 5℃ / min and 25℃ / min; the temperature can be 600℃, 700℃, 800℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃, or any other value between 600℃ and 1150℃; and the holding time can be 10min, 20min, 30min, 40min, 50min, 60min, or longer. The pressure head can be any other value between 10 min and 60 min, and the pressure head can be 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, and any other value between 1 MPa and 10 MPa. The pressure holding time can be 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, and any other value between 5 min and 60 min.

[0053] This application provides a method for preparing a heat dissipation substrate, comprising: preparing a green blank; hot-pressing and sintering the prepared green blank; and surface grinding the prepared green blank. Hot-pressing and sintering melts the metal within the composite thermally conductive material, and the molten metal coats the surface of the diamond. The diamond particles coated with the metal layer are homogeneous, or the diamond particles coated with the metal layer are mixed with the metal powder surface, resulting in more uniform powder mixing. Furthermore, the diamond particles remain solid throughout the ultrasonic densification process and hot-pressing and sintering, ensuring a nearly completely uniform distribution of diamond particles in the composite thermally conductive material. Since larger particles are more likely to contact each other, the large-diameter diamond particles form more direct heat conduction paths in the composite thermally conductive material, thereby improving thermal conductivity. Simultaneously, the molten metal coating on the surface of the diamond particles not only solves the hardness and brittleness defects of diamond material but also significantly improves the wettability between the matrix metal and the diamond, thereby reducing interfacial thermal resistance and increasing the thermal conductivity of the heat sink material.

[0054] It is worth noting that in the preparation method of the heat dissipation substrate provided in this application embodiment, during the preparation of the green blank, the green blank is placed in a vacuum hot press furnace. The vacuum hot press furnace needs to be evacuated first. During the evacuation process, the composite thermal conductive material sealed in the groove of the metal substrate body and the air in the gap of the groove can be discharged through the micropores on the cover plate. Then, heating and pressurization are performed. During the heating and pressurization process, the heating temperature, time and pressurization pressure and time are controlled so that the metal in the composite thermal conductive material melts but does not melt. The metal fills the gap of the diamond particles through plastic flow, reducing the porosity of the composite thermal conductive material and increasing the density, thereby effectively improving the heat dissipation performance of the heat dissipation substrate. To ensure that the molten metal fills the gaps between diamond particles through plastic flow, the hot-pressing sintering temperature should be determined based on the metal's melting point. The hot-pressing sintering temperature should be close to the metal's melting point but not higher. If the heating temperature is too high, the desired product cannot be obtained; if the heating temperature is too low, the metal cannot melt and fill the gaps between diamond particles, resulting in loose mixed powder and a large shrinkage rate during sintering, which affects the heat dissipation effect to some extent. If the pressure is too high, it can easily increase costs. If no pressure treatment is performed or the pressure is too low, the composite thermally conductive material will be loose, resulting in low density and a decrease in the heat dissipation performance of the heat dissipation substrate.

[0055] In some alternative embodiments, surface grinding includes: removing excess metal layers from the surface of the hot-pressed sintered blank by surface grinding, such that the thickness of the upper surface metal layer after grinding is 0.05 mm to 0.5 mm and the thickness of the lower surface metal layer is 2.5 mm to 3 mm, thereby obtaining a master blank.

[0056] For example, the blank is surface-ground so that the thickness of the upper surface metal layer after grinding can be 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm and any other value between 0.05mm and 0.5mm, and the thickness of the lower surface metal layer can be 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm and any other value between 2.5mm and 3.0mm.

[0057] This application provides a method for preparing a heat dissipation substrate, which includes: making a green blank, hot pressing and sintering the prepared green blank to obtain a cooked blank, and performing surface grinding treatment on the cooked blank. The surface grinding treatment can make the cooked blank smoother, flatter and more aesthetically pleasing. In addition, after the surface grinding treatment, the thickness of the composite thermally conductive material from the lower surface of the cooked blank is 2.5mm to 3mm, so as to facilitate the subsequent direct processing of heat dissipation fins on the lower surface of the cooked blank.

[0058] In some alternative embodiments, the method further includes: after hot pressing and sintering the green blank and grinding the surface of the finished blank, heat dissipation fins are processed on the lower surface of the mother blank using CNC technology to obtain a heat dissipation substrate.

[0059] This application provides a method for preparing a heat dissipation substrate, comprising: preparing a green blank; hot-pressing and sintering the prepared green blank to obtain a cooked blank; grinding the surface of the cooked blank to obtain a master blank; and then processing heat dissipation fins on the lower surface of the master blank. The processing of the heat dissipation fins is as follows: CNC machining the heat dissipation fins on the lower surface of the master blank; the heat dissipation fins and the metal substrate body form an integral whole. Compared with pasting the heat dissipation fins onto the metal substrate body or using a thermal interface material (TIM) to make the metal substrate body and the heat dissipation fins contact, the heat dissipation substrate provided in this application provides a method for preparing heat dissipation fins on the metal substrate body through an integral molding process, which improves the bonding strength and allows heat to be directly transferred from the metal substrate body to the heat dissipation fins, thereby enhancing the heat dissipation effect and extending the service life.

[0060] It is worth noting that the heat dissipation substrate made using the solution provided in the embodiments of this application has better heat dissipation performance than commercially available metals and metal-based composite materials, such as copper (Cu), with a thermal conductivity of ≈400W / m*k; aluminum (Al), with a thermal conductivity of ≈220W / m*k; aluminum nitride (AlN), with a thermal conductivity of 170~230W / m*k; silicon carbide / aluminum (SiCp / Al), with a thermal conductivity of 170~200W / m*k; copper-tungsten alloy (Cu / W), with a thermal conductivity of 180~200W / m*k; copper-tungsten copper-copper (CPC), with a thermal conductivity of 200~300W / m*k; and diamond, with a thermal conductivity of 2000~2200W / m*k.

[0061] According to tests, the thermal conductivity of the heat dissipation substrate provided in this application embodiment, which uses a composite of diamond particles and copper powder as the composite thermal conductive material, is 650W / m*k to 900W / m*k, and the thermal conductivity of the heat dissipation substrate which uses a composite of diamond particles and aluminum powder as the composite thermal conductive material is 500W / m*k to 750W / m*k.

[0062] For example, the thermal conductivity of a heat dissipation substrate using a composite of diamond particles and copper powder as the composite thermal conductive material can be any other value between 650 W / m*k, 700 W / m*k, 750 W / m*k, 800 W / m*k, 850 W / m*k, 900 W / m*k, and 650 W / m*k to 900 W / m*k. The thermal conductivity of a heat dissipation substrate using a composite of diamond particles and aluminum powder as the composite thermal conductive material can be any other value between 500 W / m*k, 550 W / m*k, 600 W / m*k, 650 W / m*k, 700 W / m*k, 750 W / m*k, and 500 W / m*k to 750 W / m*k.

[0063] Thirdly, embodiments of this application also provide the application of the above-described heat dissipation substrate or the heat dissipation substrate prepared by the above-described preparation method in the fabrication of heat dissipation components for electronic devices.

[0064] This application also provides an application of the aforementioned heat dissipation substrate in the fabrication of heat dissipation assemblies for electronic devices. The heat dissipation substrate is used to fabricate heat dissipation assemblies for power devices, specifically absorbing heat from the heat source (power device) and dissipating it to the surrounding environment through radiation, convection, or conduction, thereby reducing the temperature of the heat source. For example, the fabricated heat dissipation assemblies can be used for various power devices such as IGBT cooling, chip cooling, AI server cooling, CPU cooling, GPU clusters, and liquid cooling in cloud computing and big data centers.

[0065] The present application will be further described below with reference to embodiments.

[0066] This application provides a fabrication process for a heat dissipation substrate, the fabrication steps of which are as follows:

[0067] a. Mix copper powder (see Figure 1 for SEM image of copper powder) and diamond particles (see Figure 2 for SEM image of diamond particles) evenly to obtain a mixed powder;

[0068] b. According to the application scenario, a groove is processed on the copper substrate, and a copper plate matching the size of the groove is processed as a cover plate and microholes are processed on the cover plate (see Figure 3 for the main view of the copper substrate and Figure 4 for the schematic diagram of the copper substrate and the cover plate).

[0069] c. Pour the mixed powder into the substrate groove and use ultrasonic vibration to make the mixed powder densely distributed; combine the cover plate with the copper substrate containing the mixed powder to obtain the green blank;

[0070] d. Place the green embryo into a vacuum hot press furnace for hot pressing and sintering to obtain a cooked embryo;

[0071] e. Remove the excess copper layer from the surface of the cooked embryo to obtain the mother embryo;

[0072] f. Process heat dissipation fins on the lower surface of the copper layer of the mother substrate to obtain a heat dissipation substrate (see Figure 5 for a schematic diagram of the heat dissipation substrate), wherein:

[0073] In step a, the particle size of the copper powder is 5μm to 20μm; the particle size of the diamond particles is 300μm to 800μm, and the content of diamond particles in the mixed powder is ≥60wt%.

[0074] In step b, the fitting clearance between the cover plate and the groove is 0.01mm to 0.1mm, and the diameter of the micropores on the cover plate is <0.3mm;

[0075] In step c, after ultrasonic vibration, the diamond particles are densely arranged, and copper powder fills the gaps between the diamond particles; the cover plate is placed in the groove, with the upper surface of the cover plate slightly higher than the upper surface of the groove.

[0076] In step d, before hot pressing, the equipment is evacuated to a vacuum level of 5*10. -2 Below Pa; at a rate of 5℃ / min to 25℃ / min, heat to 600℃ to 1150℃, hold for 10min to 60min, pressure head pressure 1MPa to 10MPa, holding time 5min to 60min;

[0077] In step e, the thickness of the copper layer on the upper surface after grinding is 0.05mm to 0.5mm, and the thickness of the copper layer on the lower surface is 2.5mm to 3mm.

[0078] In step f, the heat dissipation fins are shovel-tooth fins, needle-shaped fins, or columnar fins, wherein: the diameter of the needle-shaped fins is 0.3-0.5 mm and the height is 2.5 ± 0.1 mm (see Figure 6 for a physical picture of the heat dissipation substrate), and the thickness of the shovel-tooth fins is 0.3-0.5 mm and the height is 2.5 ± 0.1 mm (see Figure 7 for a physical picture of the heat dissipation substrate).

[0079] The table below shows the process parameters and thermal conductivity of the prepared heat dissipation substrates for Examples 1-9 and Comparative Examples 1-10.

[0080] As can be seen from the table above, the heat dissipation substrates prepared using the methods provided in Examples 1-9 of this application have high thermal conductivity and good heat dissipation performance. In Comparative Example 1, the heat dissipation substrate was not vacuumed during the preparation process, resulting in high porosity of the composite thermally conductive material, which led to a decrease in the thermal conductivity of the prepared heat dissipation substrate. In Comparative Example 2 or Comparative Example 4, the highest temperature during the hot pressing sintering process was lower than the melting temperature of Cu powder or Al powder, and the metal failed to melt and fill the gaps between the diamond particles, resulting in a sharp decrease in the heat dissipation performance of the heat dissipation substrate. In Comparative Example 3, no pressure treatment was performed during the hot pressing sintering process, the mixed powder was relatively loose, and the adhesion between the cover plate and the metal substrate body was not tight enough, resulting in a decrease in the thermal conductivity of the heat dissipation substrate and poor heat dissipation performance. In Comparative Example 5, the highest temperature during the hot pressing sintering process was higher than the melting temperature of Cu powder, causing the Cu powder to melt and making it impossible to obtain the corresponding product. In Comparative Examples 6, 7, or 8, the holding pressure during the hot pressing sintering process was too high, the holding time was too long, or the diamond particles were too large, resulting in increased costs and energy consumption, but the thermal conductivity of the heat dissipation substrate did not improve significantly. In Comparative Examples 9 or 10, the diamond particle size was too small or the content was too low, and heat transfer mainly relied on low thermal conductivity metal materials, resulting in a decrease in the thermal conductivity of the heat dissipation substrate.

[0081] In summary, this application provides a heat dissipation substrate, its preparation method, and its application. The prepared heat dissipation substrate has excellent thermal conductivity and heat dissipation properties, and can be used to fabricate heat dissipation components for electronic devices. These components can be used for heat management of various power devices. For example, power devices such as chips generate heat during operation, leading to temperature increases and performance degradation. The heat dissipation components dissipate heat from the power devices through heat conduction and radiation, preventing performance degradation or failure due to localized overheating and ensuring efficient and stable operation. Furthermore, with the development of electronic technology, power devices (such as chips and IGBTs) are evolving towards higher power, miniaturization, and integration, resulting in a dramatic increase in the rate of heat generation per unit volume. The efficient cooling capability of the heat dissipation components allows power devices to operate stably at higher power levels, achieving higher power density within the same volume, promoting miniaturization and weight reduction of power devices, and ensuring long-term stable operation.

[0082] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A heat dissipation substrate, characterized in that, The invention includes a metal substrate body, wherein at least 75% of the area of ​​the metal substrate body has a three-layer structure, wherein the three-layer structure includes an upper surface metal layer, a composite thermally conductive material layer and a lower surface metal layer arranged sequentially, wherein the composite thermally conductive material layer is a dense sintered body, wherein the dense sintered body has a metal skeleton and diamond particles as a reinforcing phase.

2. The heat dissipation substrate according to claim 1, characterized in that, The metal substrate body has a three-layer structure in at least 85% of its area.

3. The heat dissipation substrate according to claim 1 or 2, characterized in that, The lower surface of the metal substrate body is also provided with a plurality of heat dissipation fins, wherein the heat dissipation fins are shovel-tooth fins, needle-shaped fins or columnar fins, wherein: the diameter of the needle-shaped fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm, and the thickness of the shovel-tooth fins is 0.3 to 0.5 mm and the height is 2.5 ± 0.1 mm.

4. A method for preparing a heat dissipation substrate according to any one of claims 1-3, characterized in that, Includes the following steps: A metal substrate body is provided, a groove is processed on the metal substrate body, the composite thermally conductive material is filled into the groove, and a cover plate matching the groove is added to obtain a green blank; the green blank is hot-pressed and sintered to obtain a cooked blank, and the surface of the cooked blank is ground.

5. The heat dissipation substrate according to claim 4, characterized in that, The fit clearance between the cover plate and the groove is 0.01mm to 0.1mm; the cover plate is also provided with micropores, the diameter of which is <0.3mm.

6. The preparation method according to claim 4, characterized in that, The preparation of the green embryo includes: filling the groove with the composite thermally conductive material, ultrasonically treating it, and then covering it with the cover plate, with the upper surface of the cover plate slightly higher than the height of the groove, to obtain the green embryo, wherein: The composite thermally conductive material comprises diamond particles and metal powder, wherein the content of diamond particles is ≥60wt%; the particle size of the diamond particles is 300μm to 800μm; and the particle size of the metal powder is 5μm to 20μm. The metal powder includes at least one of copper powder, aluminum powder, tungsten copper powder, and molybdenum copper powder. The diamond particles can be replaced with ceramic powder, which is selected from at least one of boron nitride powder, aluminum nitride powder, silicon carbide powder, and silicon nitride powder.

7. The preparation method according to claim 4, characterized in that, Hot pressing sintering includes: The embryo is placed in a hot press, and the hot press is evacuated to a vacuum of 5*10. -2 Below Pa, the temperature is increased to 600℃ to 1150℃ at a rate of 5℃ / min to 25℃ / min, held for 10min to 60min, and the pressure head is maintained at 1MPa to 10MPa for 5min to 60min to obtain a cooked embryo.

8. The preparation method according to claim 7, characterized in that, Surface grinding includes: removing excess metal layers from the surface of the hot-pressed sintered blank by surface grinding, so that the thickness of the upper surface metal layer after grinding is 0.05mm to 0.5mm and the thickness of the lower surface metal layer is 2.5mm to 3mm, thus obtaining a master blank.

9. The preparation method according to claim 8, characterized in that, Also includes: After the green blank is hot-pressed and sintered and the cooked blank is surface-ground, heat dissipation fins are processed on the lower surface of the mother blank using CNC technology to obtain a heat dissipation substrate. The heat dissipation substrate with diamond particles and copper powder composite as composite thermal conductive material has a thermal conductivity of 650W / m*k to 900W / m*k, and the heat dissipation substrate with diamond particles and aluminum powder composite as composite thermal conductive material has a thermal conductivity of 500W / m*k to 750W / m*k.

10. The application of the heat dissipation substrate according to any one of claims 1-3 or the heat dissipation substrate prepared by the preparation method according to any one of claims 4-9 in the manufacture of heat dissipation components for electronic devices.

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