Diamond modified high-thermal-conductivity sheet and preparation method thereof
By mixing diamond powder with liquid metal heat conduction sheets to prepare a composite thermal conduction layer and spraying a metal silver layer on the outer layer, the problem of poor wetting and easy leakage in liquid metal heat conduction sheets is solved, and efficient thermal conductivity of the thermal interface is achieved.
Patent Information
- Application Number
- CN202510097747.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-04-15
AI Technical Summary
After the existing liquid metal heat conducting flakes are melted at high temperatures, the liquid droplets will shrink and agglomerate, and cannot completely immerse the thermal interface, resulting in an increase in contact thermal resistance and unsatisfactory thermal resistance of the thermal interface. At the same time, the liquid metal heat conducting flakes are prone to leakage, which limits its promotion and application.
Diamond powder and liquid metal heat conduction sheet are mixed and stirred to prepare a composite heat conduction layer, and a silver metal layer is sprayed on the outer layer to form diamond-modified high heat conduction sheets, and the thermal conductivity is improved through casting and tableting processes.
It improves the wetting properties of liquid metal heat conducting flakes at high temperatures, reduces interface thermal resistance, enhances thermal conductivity, avoids the flow and leakage of liquid metals, and gives them a wide potential for application in the field of thermal interface materials.
Smart Images
Figure CN119823727A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of electronic packaging thermal interface materials, and in particular to a diamond-modified high thermal conductivity sheet and a preparation method thereof. Background Art
[0002] In recent years, the rapid development of aerospace, electronic technology and other fields has promoted the development of chip-level and module-level electronic devices towards miniaturization, multi-function and high power density. In the civilian field, the heat flux density generated by some chips during operation is as high as 150 W / cm 2 The power density of thousands of array elements in airborne radar can even reach 1010 W / m 2 . And as the size of electronic products decreases and the degree of integration increases, the heat generated per unit area is getting higher and higher. Relevant studies have shown that with every 18°C increase in service temperature, the failure rate of semiconductor components increases by two to three times, so the heat dissipation problem of the equipment is as worthy of attention as its performance. In the electronic packaging structure of high-density integrated circuits, thermal interface materials are required between the chip and the heat dissipation shell to efficiently conduct heat. Thermal interface materials not only need to have a high thermal conductivity, but also a low thermal expansion coefficient, which puts higher requirements on thermal management materials. At present, the common thermal interface material products on the market are thermal grease and liquid metal, but thermal grease has limited heat transfer performance and is easy to age. Liquid metal has the advantages of low melting point, high temperature resistance, high thermal conductivity, no aging, and low interface thermal resistance. It can quickly conduct heat away and is currently the most efficient thermal interface thermal conductive material. Liquid metal thermal conductive sheet is a sheet solid at room temperature, but it will melt into liquid at high operating temperature. According to the characteristics of liquid metal, the melted droplets will shrink and gather together, resulting in the inability to completely wet the entire thermal interface, which increases the contact thermal resistance and the thermal interface thermal resistance, and fails to achieve satisfactory results. Secondly, the thermal conductive sheet is installed between the CPU and the cold head, so the general working environment is vertical. After melting into liquid, it is easy to leak and cause circuit short circuit. These defects limit the promotion and application of liquid metal thermal conductive sheet. It is urgent to improve the thermal interface material of liquid metal to meet the actual use needs. Summary of the invention
[0003] Features and advantages of the invention are set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
[0004] In order to overcome the problems of the prior art, the present invention provides a diamond-modified high thermal conductivity sheet, which includes a composite thermal conductive layer and a metal silver layer sprayed on the outer layer of the composite thermal conductive layer; the material of the composite thermal conductive layer includes a mixture of diamond powder, liquid metal thermal conductive sheet, and liquid metal oxide.
[0005] Preferably, the mass fractions of the components in the composite heat-conducting layer are: 45%-50% for diamond powder, 25%-35% for liquid metal heat-conducting sheet, and 15-20% for liquid metal oxide.
[0006] Preferably, the liquid metal heat conductive sheet is made of one or more of the following materials: pure gallium, gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy or gallium-indium-tin-zinc alloy.
[0007] Preferably, the diamond powder has a particle size of 20-40 μm.
[0008] Preferably, the mass of the sprayed metal silver layer accounts for 5%-10% of the total mass of the high thermal conductive sheet.
[0009] Preferably, the present invention also provides a method for preparing a diamond-modified high thermal conductivity sheet, which is used to prepare the diamond-modified high thermal conductivity sheet, and specifically comprises the following steps: After weighing the diamond powder, the liquid metal thermal conductive sheet, and the liquid metal oxide, the liquid metal oxide and the diamond powder are first stirred with a vacuum stirrer at a speed of 1000 r / min for a preset time and then taken out, and then the mixed powder is poured into the molten liquid metal thermal conductive sheet and stirred with an electric stirrer to obtain a composite thermal conductive material; Processing and pressing: After pressing the composite thermal conductive material into sheets, cutting into required sizes according to actual use needs to obtain the composite thermal conductive layer; Surface treatment: a layer of silver is evenly sprayed on the outer surface of the composite thermal conductive layer by spraying to obtain a diamond-modified high thermal conductive sheet.
[0010] Preferably, the obtained diamond-modified high thermal conductive sheet needs to be vacuum packaged and sealed before normal storage and transportation.
[0011] Beneficial effects of the present invention: The present invention is to mix and stir diamond powder with molten thermal conductive sheet, perform surface modification on diamond powder, and then produce diamond modified high thermal conductive sheet by casting and pressing. After the diamond modified high thermal conductive sheet is installed and used, the wettability of the chip becomes better, which solves the problem of fluidity of liquid metal thermal conductive sheet after melting and poor wetting of thermal conductive interface. Finally, the interface thermal resistance is further reduced by surface treatment of the produced high thermal conductive sheet, and the contact thermal resistance is reduced, so that the thermal conductivity is fully exerted and the thermal conductivity is improved. The diamond modified high thermal conductive sheet eliminates the defects of fluidity and droplet agglomeration of a single thermal conductive sheet. Compared with a single thermal conductive sheet, it has good wettability on the thermal interface and reduces the contact thermal resistance of the thermal interface. Combined with the high thermal conductivity of diamond powder and the surface treatment of the overall diamond modified high thermal conductive sheet, the diamond modified high thermal conductive sheet can fully exert its thermal conductivity, and the high thermal conductive sheet is simple to install and convenient to use, and is expected to be widely used in the field of thermal interface materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples, and the advantages and implementation methods of the present invention will become more obvious. The contents shown in the accompanying drawings are only used to explain the present invention and do not constitute any limitation to the present invention in any sense. In the accompanying drawings: Figure 1 The figure is a schematic diagram of the structure of a diamond-modified high thermal conductive sheet in a specific embodiment of the present invention. DETAILED DESCRIPTION
[0013] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0014] Example 1
[0015] like Figure 1 As shown, this embodiment provides a diamond-modified high thermal conductivity sheet, which includes a composite thermal conductive layer 1 and a metal silver layer 2 sprayed on the outer layer of the composite thermal conductive layer 1; the material of the composite thermal conductive layer 1 includes a mixture of diamond powder, liquid metal thermal conductive sheet, and liquid metal oxide. The mass fractions of the components in the composite thermal conductive layer 1 are: 45%-50% for diamond powder, 25%-35% for liquid metal thermal conductive sheet, and 15-20% for liquid metal oxide. The liquid metal thermal conductive sheet is made of one or more materials selected from pure gallium, gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy, or gallium-indium-tin-zinc alloy. The powder particle size of the diamond powder is 20-40μm. The mass of the sprayed metal silver layer 2 accounts for 5%-10% of the total mass of the high thermal conductive sheet.
[0016] Example 2
[0017] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 50% diamond powder, 25% liquid metal heat-conducting sheet, and 20% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 5% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is pure gallium. The powder particle size of the diamond powder is 20 μm.
[0018] Example 3
[0019] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 45% diamond powder, 30% liquid metal heat-conducting sheet, and 18% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 7% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is a gallium-indium-tin-zinc alloy. The powder particle size of the diamond powder is 30 μm.
[0020] Example 4
[0021] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 47% diamond powder, 32% liquid metal heat-conducting sheet, and 15% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 6% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is a gallium-indium-tin alloy. The powder particle size of the diamond powder is 40 μm.
[0022] Example 5
[0023] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 46% diamond powder, 28% liquid metal heat-conducting sheet, and 16% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 10% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is a gallium-tin alloy. The powder particle size of the diamond powder is 35 μm.
[0024] Example 6
[0025] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 45% diamond powder, 35% liquid metal heat-conducting sheet, and 15% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 5% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is a gallium-zinc alloy. The powder particle size of the diamond powder is 25 μm.
[0026] Example 7
[0027] This embodiment provides a diamond-modified high thermal conductivity sheet, which is different from Embodiment 1 in that: The mass fractions of the components in the composite heat-conducting layer 1 are: 49% diamond powder, 26% liquid metal heat-conducting sheet, and 16% liquid metal oxide. The mass of the sprayed metal silver layer 2 accounts for 9% of the total mass of the high heat-conducting sheet. The liquid metal heat-conducting sheet is a gallium-indium alloy. The powder particle size of the diamond powder is 38 μm.
[0028] Example 8
[0029] This embodiment provides a method for preparing a diamond-modified high thermal conductivity sheet, which is used to prepare the diamond-modified high thermal conductivity sheet, and specifically comprises the following steps: After weighing the diamond powder, the liquid metal thermal conductive sheet, and the liquid metal oxide, the liquid metal oxide and the diamond powder are first stirred with a vacuum stirrer at a speed of 1000 r / min for 4-10 minutes and then taken out to fully mix them, and then the mixed powder is poured into the molten liquid metal thermal conductive sheet and stirred with an electric stirrer to obtain a composite thermal conductive material; Processing and pressing: the composite heat-conducting material is firstly processed by a casting machine, and then processed and pressed by a calender, and then cut into required sizes according to actual use needs to obtain the composite heat-conducting layer 1; Surface treatment: A layer of silver is evenly sprayed on the outer surface of the composite thermal conductive layer 1 by spraying, which changes the wettability of the surface of the high thermal conductive sheet, improves the thermal conductivity and reduces the interface thermal resistance. It can also inhibit the flow of internal liquid metal during operation, thereby obtaining a diamond-modified high thermal conductive sheet.
[0030] The obtained diamond-modified high thermal conductivity sheet is then vacuum packaged to prevent oxidation and sulfurization, and can be stored and transported normally after sealing.
[0031] In actual use, tear off the release film of the diamond-modified high thermal conductivity sheet, use a flexible suction cup to suck the high thermal conductivity sheet, gently place it on the IC, and after safety protection, press the cold head and tighten the screws. When the chip generates heat during operation and the temperature rises, the liquid metal in the high thermal conductivity sheet melts and fully fills the diamond powder, reducing the interface thermal resistance and giving full play to the thermal conductivity. In addition, the high thermal conductivity sheet after surface treatment further reduces the interface thermal resistance, allowing the overall composite thermal conductivity sheet to exert excellent thermal conductivity.
[0032] The preferred embodiments of the present invention are described above with reference to the accompanying drawings. A person skilled in the art may implement the present invention in a variety of variations without departing from the scope and essence of the present invention. For example, a feature shown or described as part of one embodiment may be used in another embodiment to obtain another embodiment. The above are only preferred feasible embodiments of the present invention, and do not limit the scope of rights of the present invention. Any equivalent changes made using the contents of the present specification and the accompanying drawings are included in the scope of rights of the present invention.
Claims
1. A diamond-modified high thermal conductivity sheet, characterized in that: The high thermal conductivity sheet comprises a composite thermal conductive layer and a metal silver layer sprayed on the outer layer of the composite thermal conductive layer; the composite thermal conductive layer is made of a mixture of diamond powder, liquid metal thermal conductive sheet and liquid metal oxide.
2. The diamond-modified high thermal conductive sheet according to claim 1, characterized in that: The mass fractions of the components in the composite heat-conducting layer are: 45%-50% for diamond powder, 25%-35% for liquid metal heat-conducting sheet, and 15%-20% for liquid metal oxide.
3. The diamond-modified high thermal conductive sheet according to claim 1, characterized in that: The liquid metal heat conductive sheet is made of one or more materials selected from the group consisting of pure gallium, gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy, or gallium-indium-tin-zinc alloy.
4. The diamond-modified high thermal conductive sheet according to claim 1, characterized in that: The diamond powder has a particle size of 20-40 μm.
5. The diamond-modified high thermal conductive sheet according to claim 1, characterized in that: The mass of the sprayed metal silver layer accounts for 5%-10% of the total mass of the high thermal conductivity sheet.
6. A method for preparing a diamond-modified high thermal conductive sheet, characterized in that: The method for preparing a diamond-modified high thermal conductive sheet as claimed in any one of claims 1 to 5 comprises the following steps: After weighing the diamond powder, the liquid metal thermal conductive sheet, and the liquid metal oxide, the liquid metal oxide and the diamond powder are first stirred with a vacuum stirrer at a speed of 1000 r / min for a preset time and then taken out, and then the mixed powder is poured into the molten liquid metal thermal conductive sheet and stirred with an electric stirrer to obtain a composite thermal conductive material; Processing and pressing: After pressing the composite thermal conductive material into sheets, cutting into required sizes according to actual use needs to obtain the composite thermal conductive layer; Surface treatment: a layer of silver is evenly sprayed on the outer surface of the composite thermal conductive layer by spraying to obtain a diamond-modified high thermal conductive sheet.
7. The method for preparing a diamond-modified high thermal conductive sheet according to claim 6, characterized in that: The obtained diamond-modified high thermal conductivity sheet needs to be vacuum packaged and sealed for normal storage and transportation.