Thermal interface and method of obtaining same, method of facilitating heat transfer

Abstract

The application discloses a thermal interface and a method for obtaining the same, and a method for promoting heat conduction, and belongs to the field of interface heat transfer. The thermal interface comprises a wetting layer and a liquid metal layer, the wetting layer comprises a rough surface, the wetting layer is located between a device and the liquid metal layer, and the rough surface of the wetting layer is in contact with the liquid metal layer. The wetting property between the wetting layer and the liquid metal layer is stronger than the wetting property between the surface of the device and the liquid metal layer, the rough surface of the wetting layer has a microstructure, and when the rough surface of the wetting layer is in contact with the liquid metal layer, the wetting property between the wetting layer and the liquid metal layer can be further improved through capillary effect. The wetting property between the liquid metal and the surface of the device can be effectively improved by using the thermal interface, so that the thermal interface can promote heat conduction between the device and the liquid metal layer, and can reduce the thermal resistance between the interfaces.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of interface heat transfer, in particular to a thermal interface and a method for obtaining the same, and a method for promoting heat conduction. BACKGROUND

[0002] For heat dissipation of miniaturized and high-frequency electronic devices, a thermal interface material (TIM) is usually arranged between an electronic chip and a heat sink, and the TIM is used to fill micro-pores between the electronic chip and the heat sink, so as to quickly and efficiently transfer heat.

[0003] In the related art, a liquid metal is used as a thermal interface material, and the liquid metal is bonded to the surface of an electronic chip or the surface of a heat sink through an adhesive.

[0004] In the process of implementing the present application, the inventors have found that at least the following problems exist in the related art:

[0005] The wettability between the liquid metal and the surface of the electronic chip or the surface of the heat sink is poor, which easily leads to the formation of high thermal resistance between the interfaces. SUMMARY

[0006] In view of this, the present application provides a thermal interface and a method for obtaining the same, and a method for promoting heat conduction, which can solve the above technical problems.

[0007] Specifically, the technical solutions include the following:

[0008] On one hand, the present application provides a thermal interface, which comprises: a wetting layer and a liquid metal layer, the wetting layer comprises a rough surface;

[0009] The wetting layer is located between a device and the liquid metal layer, and the rough surface of the wetting layer is in contact with the liquid metal layer.

[0010] The wetting layer is a layer prepared by using a wetting material, and the wetting material has a certain mutual solubility with the liquid metal, so that the wettability between the wetting layer and the liquid metal layer is stronger than the wettability between the surface of the device and the liquid metal layer.

[0011] The rough surface of the wetting layer has a plurality of recesses and corresponding protrusions, so that the rough surface presents a microstructure (also referred to as a floating structure) with unevenness, and the depth of the recesses and the height of the protrusions are expected to be in the micro-nanometer scale, further in the sub-micron to nanometer scale.

[0012] The liquid metal layer comprises opposite first and second surfaces, and the first and second surfaces of the liquid metal layer are respectively used for heat conduction with different devices.

[0013] As an example, one of the first surface and the second surface of the liquid metal layer is in contact with the rough surface of the wetting layer.

[0014] As another example, the opposite two surfaces of the liquid metal layer are respectively in contact with the rough surfaces of two wetting layers, that is, the first surface of the liquid metal layer is in contact with the rough surface of the first wetting layer, and the second surface of the liquid metal layer is in contact with the rough surface of the second wetting layer.

[0015] The above heat interface provided by the embodiments of the present application can improve the wettability between the liquid metal and the device surface, so that the heat interface can promote the heat conduction (i.e. thermal contact) between the device and the liquid metal layer, and can reduce the thermal resistance between the interfaces.

[0016] In some possible implementation manners, the surface roughness of the rough surface of the wetting layer is less than or equal to 3 microns.

[0017] The rough surface of the wetting layer can generate a stronger capillary effect, significantly reduce the contact angle between the wetting layer and the liquid metal layer, and achieve good heat conduction between the liquid metal layer and the device. In addition, the rough surface of the wetting layer can effectively resist the stronger flowability of the liquid metal at high temperature while ensuring the adsorption of the liquid metal, thereby solving the problem of high-temperature overflow of the liquid metal, which is also very advantageous for reducing the thermal resistance between the interfaces.

[0018] In some possible implementation manners, the wetting layer is prepared by using a wetting material, the wetting material is mutually soluble with the liquid metal layer, and the wetting material has thermal conductivity.

[0019] In some possible implementation manners, the wetting material is selected from at least one of In, Cu, Ni, Au, Fe and alloys thereof.

[0020] The wetting material can be adaptively selected according to the type of the liquid metal to be contacted, as long as the selected wetting material has good wettability with the liquid metal layer.

[0021] For example, when the liquid metal layer is selected to be a gallium-based liquid metal, the wetting material can be selected to be In and / or In alloy, and the interface of the two has excellent wettability.

[0022] In some possible implementation manners, the thickness of the wetting layer is 0.5 microns-3 microns.

[0023] In some possible implementations, the preparation raw material of the liquid metal layer comprises at least one of a gallium-based liquid metal, an indium-based liquid metal, and a bismuth-based liquid metal.

[0024] For example, the gallium-based liquid metal, the indium-based liquid metal, and the bismuth-based liquid metal include, but are not limited to, the following: a gallium-indium alloy (Ga-In), a gallium-tin alloy (Ga-Sn), a gallium-indium-tin alloy (Ga-In-Sn), an indium-gallium-tin-bismuth alloy, an indium-tin-bismuth alloy, a gallium-bismuth-indium-thallium-tin-copper alloy, a gallium-bismuth-indium-cesium alloy, a gallium-bismuth-indium-molybdenum alloy, a gallium-bismuth-indium-cesium-sulfur alloy, and the like.

[0025] In some possible implementations, the preparation raw material of the liquid metal layer further comprises an auxiliary material for improving at least one of the following properties of the liquid metal layer: thermal conductivity, corrosion resistance, wettability, viscosity.

[0026] In some possible implementations, the auxiliary material is a thermal conductive material.

[0027] In some possible implementations, the thermal conductive material is selected from at least one of diamond powder, SiC powder, AlN powder, W metal powder, Cu metal powder, and Ni metal powder.

[0028] The ceramic thermal conductive material can play a role of a thermal conductive frame, and the metal thermal conductive material has more excellent wettability with the liquid metal, and can also play a role of improving the high-temperature viscosity of the liquid metal layer and inhibiting separation of the liquid metal from the thermal conductive material.

[0029] In some possible implementations, the wetting layer has two layers, and the two opposite surfaces of the liquid metal layer are respectively in contact with the rough surfaces of the two wetting layers.

[0030] In some possible implementations, the device comprises a heat source and / or a heat dissipation source.

[0031] In some examples, the device comprises a heat source, and the thermal interface comprises a wetting layer applied to the surface of the heat source, and a liquid metal layer in contact with the rough surface of the wetting layer.

[0032] In some examples, the device comprises a heat dissipation source, and the thermal interface comprises a wetting layer applied to the surface of the heat dissipation source, and a liquid metal layer in contact with the rough surface of the wetting layer.

[0033] In some examples, the device comprises a heat source and a heat dissipation source, and the thermal interface comprises a wetting layer applied to the surface of the heat source, a wetting layer applied to the surface of the heat dissipation source, and a liquid metal layer in contact with the rough surfaces of the two wetting layers, respectively.

[0034] In another aspect, the embodiments of the present application also provide a method for obtaining a thermal interface, the thermal interface being the thermal interface described above.

[0035] The method for obtaining the thermal interface comprises: applying a wetting material layer on a surface of a device by using a wetting material.

[0036] The surface of the wetting material layer away from the surface of the device is roughened to form a wetting layer with a rough surface.

[0037] The rough surface of the wetting layer is contacted with a liquid metal layer. In this way, the thermal interface obtained by the embodiments of the present application comprises: the wetting layer and the liquid metal layer, and the liquid metal layer is in contact with the rough surface of the wetting layer.

[0038] The roughening method for the surface includes but is not limited to: solvent etching, electrochemical sandblasting (such as alternating current electrolytic corrosion), chemical polishing, plasma etching, etc.

[0039] In some possible implementations, the wetting material layer is applied on the surface of the device by a thin film deposition process. The thin film deposition process includes but is not limited to: magnetron sputtering, electron beam evaporation, vacuum evaporation, etc.

[0040] In some possible implementations, the surface of the wetting material layer is roughened by a solvent etching method.

[0041] In some possible implementations, the roughening of the surface of the wetting material layer by the solvent etching method comprises:

[0042] A corrosive solvent with a set mass concentration is applied to the surface of the wetting material layer, and the corrosion treatment is performed for a set time to form the wetting layer with the rough surface.

[0043] In some possible implementations, the corrosive solvent is a hydrochloric acid solution, and the mass concentration of the hydrochloric acid solution is 1.5%-10%.

[0044] In some possible implementations, the corrosion treatment time is 5 seconds-2 minutes.

[0045] The thermal interface provided by the embodiments of the present application uses a material with a certain mutual solubility with liquid metal as the wetting material, and on this basis, the surface of the wetting material layer is roughened by acid etching, and then a nanoscale floating surface is formed, which is beneficial to greatly increasing the specific surface area and introducing capillary effect to a certain extent, so as to greatly optimize the wettability between the wetting layer and the liquid metal layer. In particular, the method for obtaining the wetting layer is simple and easy to operate, low in cost, and convenient for large-scale popularization and application.

[0046] In another aspect, the embodiments of the present application also provide an electronic product, which comprises the thermal interface and the device as described above.

[0047] The thermal interface is located on the surface of the device.

[0048] Based on the use of the thermal interface, the electronic product provided by the embodiments of the present application not only has excellent heat dissipation performance, but also can avoid the high-temperature overflow problem of the liquid metal.

[0049] In some possible implementations, the device comprises a heat source and / or a heat dissipation source.

[0050] In some examples, the device comprises a heat source and a thermal interface, and the thermal interface comprises a wetting layer applied to the surface of the heat source and a liquid metal layer in contact with the rough surface of the wetting layer.

[0051] In some examples, the device comprises a heat dissipation source and a thermal interface, and the thermal interface comprises a wetting layer applied to the surface of the heat dissipation source and a liquid metal layer in contact with the rough surface of the wetting layer.

[0052] In some possible implementations, the device comprises a heat source and a heat dissipation source.

[0053] The thermal interface comprises a first wetting layer, a liquid metal layer and a second wetting layer.

[0054] The first wetting layer is located on the surface of the heat source, and the rough surface of the first wetting layer is in contact with the first surface of the liquid metal layer.

[0055] The second wetting layer is located on the surface of the heat dissipation source, and the rough surface of the second wetting layer is in contact with the second surface of the liquid metal layer.

[0056] In some possible implementations, the heat source includes but is not limited to an electronic chip, an integrated circuit chip, etc., and the heat dissipation source includes but is not limited to a heat sink, such as a liquid cooling plate, a VC heat sink, etc.

[0057] The electronic product provided by the embodiments of the present application is particularly suitable for use as a high-energy-density electronic device product, such as a chip, an insulated gate bipolar transistor (IGBT), etc.

[0058] In another aspect, the embodiments of the present application also provide a method for facilitating heat conduction between a device and a liquid metal layer, which comprises applying a wetting layer to the surface of the device, the wetting layer having a rough surface.

[0059] contacting the rough surface of the wetting layer with a liquid metal layer to form a thermal interface, wherein the thermal interface is as described above.

[0060] By applying a wetting layer on the surface of the device, the rough surface of the wetting layer is contacted with a liquid metal layer, the wettability between the wetting layer and the liquid metal layer is stronger than the wettability between the surface of the device and the liquid metal layer, on the other hand, the rough surface of the wetting layer has a microstructure, which can further improve the wettability between the wetting layer and the liquid metal layer through capillary effect when it is contacted with the liquid metal layer, finally, the heat conduction between the device and the liquid metal layer is improved, and the thermal resistance between the interfaces is reduced.

[0061] In another aspect, the embodiments of the present application also provide a method for thermally abutting a heat source to a heat sink, the method comprising: applying a first wetting layer on the surface of the heat source, the first wetting layer having a rough surface; and applying a second wetting layer on the surface of the heat sink, the second wetting layer having a rough surface;

[0062] applying a liquid metal layer between the rough surface of the first wetting layer and the rough surface of the second wetting layer, so that the two surfaces of the liquid metal layer are respectively contacted with the rough surfaces of the corresponding wetting layers to form a thermal interface;

[0063] wherein the thermal interface is as described above.

[0064] By applying a wetting layer on the surface of the device, the rough surface of the wetting layer is contacted with a liquid metal layer, the wettability between the wetting layer and the liquid metal layer is stronger than the wettability between the surface of the device and the liquid metal layer, on the other hand, the rough surface of the wetting layer has a microstructure, which can further improve the wettability between the wetting layer and the liquid metal layer through capillary effect when it is contacted with the liquid metal layer, finally, the heat conduction between the device and the liquid metal layer is improved, and the thermal resistance between the interfaces is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is a structural schematic diagram of a thermal interface provided by the embodiments of the present application;

[0066] Figure 2 is a structural schematic diagram of another thermal interface provided by the embodiments of the present application;

[0067] Figure 3 is a structural schematic diagram of a thermal interface applied to a heat source provided by the embodiments of the present application;

[0068] Figure 4 is a structural schematic diagram of a thermal interface applied to a heat sink provided by the embodiments of the present application;

[0069] Figure 5 is a structural schematic diagram of a thermal interface provided by an embodiment of the present application, which is applied to a heat source and a heat dissipation source simultaneously;

[0070] Figure 6 is a flowchart of a method for obtaining a thermal interface provided by an embodiment of the present application;

[0071] Figure 7 is a surface topography diagram of an In material wettability layer provided by an embodiment of the present application;

[0072] Figure 8 is a data distribution diagram obtained by surface roughness testing of an In coating before and after acid etching respectively provided by an embodiment of the present application, wherein A diagram corresponds to the In coating before acid etching, and B diagram corresponds to the In coating with a rough surface after acid etching. In addition, the sampling positions of A diagram and B diagram are different, so the corresponding data at the respective positions may not correspond one by one, but this does not affect the accurate judgment of the surface roughness before and after acid etching;

[0073] Figure 9 is a contact angle test diagram obtained by adding gallium indium tin liquid metal to the surface of a silicon coating of elemental silicon provided by an embodiment of the present application;

[0074] Figure 10 is a contact angle test diagram obtained by adding gallium indium tin liquid metal to the surface of an In coating provided by an embodiment of the present application;

[0075] Figure 11 is a contact angle test diagram obtained by adding gallium indium tin liquid metal to the acid etched surface of an In coating provided by an embodiment of the present application;

[0076] Figure 12 is a flowchart of a method for promoting heat conduction between a device and a liquid metal layer provided by an embodiment of the present application;

[0077] Figure 13 is a flowchart of a method for thermally abutting a heat source to a heat dissipation source provided by an embodiment of the present application.

[0078] The reference signs are respectively represented as:

[0079] 000-thermal interface;

[0080] 100-wettability layer; 1001-rough surface; 101-first wettability layer, 102-second wettability layer;

[0081] 200-liquid metal layer;

[0082] 300-device; 301-heat source; 302-heat dissipation source. Detailed Implementation

[0083] To make the technical solutions and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0084] With the trend towards miniaturization and higher frequency operation of electronic components, the total power density of electronic chips has increased significantly, leading to a corresponding increase in heat flux density and consequently, higher operating temperatures. Excessive operating temperature directly affects the lifespan and stability of electronic components. Therefore, efficient heat dissipation is essential for electronic chips, especially those with ultra-high heat flux density.

[0085] Currently, thermal interface materials are often used to fill the micropores between electronic chips and heat sinks. This allows heat from the electronic chip to be transferred to the heat sink via the thermal interface material, achieving rapid and efficient heat transfer. With the increasing use of liquid cooling plates and vapor chambers (VCs) in heat sinks (also known as planar heat pipes, vapor chambers, or heat spreaders), the surfaces of these heat sinks that contact the electronic chip are generally smooth, leading to increasingly stringent requirements for thermal interface materials.

[0086] Liquid metal is a highly promising thermal interface material, with an intrinsic thermal conductivity exceeding 15 W / mK, dozens of times higher than that of silicone oil. However, liquid metal exhibits non-wetting or semi-wetting properties with most metallic or non-metallic surfaces, significantly increasing interfacial thermal resistance. To improve the wettability (also known as wettability) of liquid metal with metallic or non-metallic surfaces, related technologies utilize liquid metal as a thermal interface material, bonding it to the surface of electronic chips or heat sinks using adhesives.

[0087] However, the improvement effect of this method is not obvious. The wettability between liquid metal and the surface of electronic chip or heat sink is still poor, which can easily lead to high thermal resistance at the interface.

[0088] In one aspect, embodiments of this application provide a thermal interface, as shown in the attached figure. Figure 1 As shown, the thermal interface 000 includes: a wetting layer 100 and a liquid metal layer 200, the wetting layer 100 having a rough surface 1001; the wetting layer 100 is located between the device 300 and the liquid metal layer 200, and the rough surface 1001 of the wetting layer 100 is in contact with the liquid metal layer 200.

[0089] In this embodiment, the wetting layer 100 is prepared using a wetting material. The wetting material and the liquid metal have a certain degree of mutual solubility, which makes the wettability between the wetting layer 100 and the liquid metal layer 200 stronger than the wettability between the surface of the device 300 and the liquid metal layer 200.

[0090] The rough surface 1001 of the wetting layer 100 refers to a surface having a plurality of recesses and corresponding protrusions thereon, and the depth of the recesses or the height of the protrusions is expected to be in the micro-nanometer scale, so that the rough surface 1001 presents a microstructure (also referred to as a bump structure) with unevenness. Further, the microstructure is expected to be in the sub-micron to nanometer size.

[0091] In the embodiment of the present application, the wetting layer 100 with the rough surface 1001 is arranged on the surface of the device 300 as a thermal interface 000. On the one hand, the wettability between the wetting layer 100 and the liquid metal layer 200 is stronger than the wettability between the surface of the device 300 and the liquid metal layer 200. On the other hand, the rough surface 1001 of the wetting layer 100 has a microstructure, which, when in contact with the liquid metal layer 200, can further improve the wettability between the wetting layer 100 and the liquid metal layer 200 through capillary effect. It can be seen that the thermal interface 000 provided by the embodiment of the present application can promote the heat conduction (i.e. thermal contact) between the device 300 and the liquid metal layer 200, and effectively reduce the thermal resistance between the interfaces.

[0092] In the embodiment of the present application, the microstructure with unevenness on the rough surface 1001 of the wetting layer 100 is expected to be in the sub-micron to nanometer size. For example, the surface roughness of the rough surface 1001 of the wetting layer 100 is less than or equal to 3 microns, such as less than or equal to 2.5 microns, less than or equal to 2.4 microns, less than or equal to 2.3 microns, less than or equal to 2.2 microns, less than or equal to 2.1 microns, less than or equal to 2 microns, less than or equal to 1.5 microns, less than or equal to 1 micron, less than or equal to 900 nanometers, less than or equal to 800 nanometers, less than or equal to 500 nanometers, less than or equal to 200 nanometers, less than or equal to 100 nanometers, less than or equal to 80 nanometers, less than or equal to 50 nanometers, etc.

[0093] The micro-nanometer scale rough surface 1001 of the wetting layer 100 can produce stronger capillary effect, significantly reduce the contact angle between the wetting layer 100 and the liquid metal layer 200, and achieve good heat conduction between the liquid metal layer 200 and the device 300. In addition, the rough surface 1001 of the wetting layer 100 can effectively resist the stronger flowability of the liquid metal at high temperature while ensuring the adsorption of the liquid metal, thereby solving the problem of high-temperature overflow of the liquid metal, which is also very advantageous for reducing the thermal resistance between the interfaces.

[0094] The infiltrating layer 100 is prepared by using an infiltrating material. It is expected that the infiltrating material is capable of conducting heat and has a certain mutual solubility with the liquid metal, i.e., capable of promoting the solubility between the infiltrating layer 100 and the liquid metal layer 200. The infiltrating material satisfying the above requirements is suitable for the present application.

[0095] For example, the infiltrating material used in the embodiments of the present application includes, but is not limited to, at least one of the following metal raw materials: In, In alloy, Cu, Cu alloy, Ni, Ni alloy, Au, Au alloy, Fe, Fe alloy. For example, the In alloy includes, but is not limited to, In-Bi alloy, In-Sn alloy, In-Mo alloy, etc.

[0096] For example, the infiltrating material can be any one of the above-mentioned metal raw materials. Using one kind of metal raw material as the infiltrating material has the advantages of simple film formation and facilitating the reduction of the interface thermal resistance.

[0097] For example, the infiltrating material can also be a combination of any one of the above-mentioned metal raw materials and alloys thereof, or a combination of any two or more of the metal raw materials, for example, In and Ni are used in combination, or Cu and Fe are used in combination, etc.

[0098] The type of the infiltrating material can be adaptively selected according to the type of the liquid metal to be contacted, as long as the selected infiltrating material enables the infiltrating layer 100 to have good wettability with the liquid metal layer 200.

[0099] For example, when the liquid metal layer 200 is selected to be a gallium-based liquid metal, the infiltrating material can be selected to be In and / or In alloy, and the interface of the two has excellent wettability.

[0100] In the embodiments of the present application, the thickness of the infiltrating layer 100 applied to the surface of the device 300 is considered according to at least one of the following situations: device type, device volume, device heat dissipation requirement, etc. Generally, the thickness of the infiltrating layer 100 can be 0.5-3 microns, for example, 0.5 microns, 0.6 microns, 0.7 microns, 0.8 microns, 0.9 microns, 1 micron, 1.2 microns, 1.5 microns, 1.8 microns, 2 microns, 2.3 microns, 2.5 microns, 2.7 microns, 2.9 microns, etc. The above-mentioned thickness of the infiltrating layer 100 can be considered as its average thickness.

[0101] As shown in FIG. 1, the thermal interface 1000 provided by the embodiments of the present application further includes a liquid metal layer 200 in contact with the rough surface 1001 of the infiltrating layer 100. Figure 1

[0102] ​The liquid metal layer 200 includes opposite first and second surfaces, and the first and second surfaces of the liquid metal layer 200 are configured to conduct heat to different devices 300, respectively.

[0103] As an example, one of the first and second surfaces of the liquid metal layer 200 is in contact with the rough surface 1001 of the wetting layer 100.

[0104] As another example, as shown in FIG. 2B, the opposite two surfaces of the liquid metal layer 200 are in contact with the rough surface 1001 of the wetting layer 100, respectively, that is, the first surface of the liquid metal layer 200 is in contact with the rough surface 1001 of the first wetting layer 101, and the second surface of the liquid metal layer 200 is in contact with the rough surface 1001 of the second wetting layer 102. Figure 2

[0105] The liquid metal layer 200 is configured to facilitate heat conduction between different devices 300, such as a heat source 301 and a heat sink 302, and the liquid metal layer 200 is prepared from at least a liquid metal that is in liquid state at least in a working temperature range (e.g., 20-100°C) of the devices 300.

[0106] For example, the liquid metal can be at least one of a gallium-based liquid metal, an indium-based liquid metal, and a bismuth-based liquid metal, which has a higher thermal conductivity.

[0107] For example, the gallium-based liquid metal, the indium-based liquid metal, and the bismuth-based liquid metal can include, but are not limited to, the following: a gallium-indium alloy (Ga-In), a gallium-tin alloy (Ga-Sn), a gallium-indium-tin alloy (Ga-In-Sn), an indium-gallium-tin-bismuth alloy, an indium-tin-bismuth alloy, a gallium-bismuth-indium-thallium-tin-copper alloy, a gallium-bismuth-indium-cesium alloy, a gallium-bismuth-indium-molybdenum alloy, a gallium-bismuth-indium-cesium-sulfur alloy, and the like.

[0108] In some examples, the liquid metal layer 200 of the thermal interface 000 provided by the embodiments of the present application adopts a gallium-indium alloy (Ga-In), for example, the mass percentage of indium is 18%-25%, and the wetting layer 100 can adopt an In or alloy coating.

[0109] In some examples, the liquid metal layer 200 of the thermal interface 000 provided by the embodiments of the present application adopts a gallium-indium-tin alloy (Ga-In-Sn), for example, the mass percentage of In is 15%-22%, and the mass percentage of Sn is 8%-18%, and the wetting layer 100 adopts an In or alloy coating.

[0110] ​In some possible implementations, in addition to the liquid metal, the liquid metal layer 200 can further include an auxiliary material. The auxiliary material is used to adjust other properties of the liquid metal layer 200 without affecting the basic properties of the liquid metal layer 200. For example, the auxiliary material is used to improve at least one of the following properties of the liquid metal layer 200: thermal conductivity, corrosion resistance, wettability, and viscosity.

[0111] In some examples, the auxiliary material can be a thermally conductive material, which is used to further improve the thermal conductivity of the liquid metal layer 200. For example, the thermally conductive material can be selected from a high-thermal-conductivity ceramic thermally conductive material, such as diamond powder, SiC powder, AlN powder, or the like. The ceramic thermally conductive material can function as a thermally conductive frame.

[0112] The thermally conductive material can also be selected from a metal thermally conductive material, such as W metal powder, Cu metal powder, Ni metal powder, or the like. The metal thermally conductive material has better wettability with the liquid metal, and can also function to improve the high-temperature viscosity of the liquid metal layer 200 and inhibit separation of the liquid metal from the thermally conductive material.

[0113] The thermally conductive material can be selected from a single type or a combination of multiple types. The particle size of the above-mentioned thermally conductive material powders is 10 nm to 50 μm, for example, 100 nm to 20 μm, for example, 100 nm to 500 nm, 1 μm to 10 μm, 5 μm to 15 μm, 20 μm to 30 μm, or the like.

[0114] In the embodiments of the present application, the thickness of the liquid metal layer 200 can be determined according to the desired thermal resistance. The thickness of the liquid metal layer 200 is directly proportional to the thermal resistance. For example, the thickness of the liquid metal layer 200 can be 1 μm to 100 μm, for example, 1 μm to 5 μm, 5 μm to 15 μm, 10 μm to 20 μm, 15 μm to 40 μm, 20 μm to 50 μm, 40 μm to 70 μm, or the like.

[0115] The thermal interface 000 provided in the embodiments of the present application is applied to the surface of a device 300. The device 300 can include, but is not limited to, a heat source 301 and / or a heat dissipation source 302.

[0116] After the thermal interface 000 is applied to the surface of the device 300, the liquid metal can be prevented from reacting with the material of the device 300, and at the same time, the liquid metal layer 200 can be in sufficient thermal conduction with the surface of the device 300.

[0117] In some examples, as shown in FIG. 2, the device 300 can include a heat source 301 and a heat dissipation source 302. Figure 3As shown, the device 300 includes a heat source 301, and the thermal interface 000 can include: an infiltration layer 100 applied to the surface of the heat source 301, and a liquid metal layer 200 in contact with the rough surface 1001 of the infiltration layer 100.

[0118] In some examples, as shown in FIG. 2, the device 300 includes a heat source 301, and the thermal interface 000 can include: an infiltration layer 100 applied to the surface of the heat source 301, and a liquid metal layer 200 in contact with the rough surface 1001 of the infiltration layer 100. Figure 4 As shown, the device 300 includes a heat source 301, and the thermal interface 000 can include: an infiltration layer 100 applied to the surface of the heat source 301, and a liquid metal layer 200 in contact with the rough surface 1001 of the infiltration layer 100.

[0119] In some examples, as shown in FIG. 2, the device 300 includes a heat source 301, and the thermal interface 000 can include: an infiltration layer 100 applied to the surface of the heat source 301, and a liquid metal layer 200 in contact with the rough surface 1001 of the infiltration layer 100. Figure 5 As shown, the device 300 includes a heat source 301 and a heat sink 302, and the thermal interface 000 can include: a first infiltration layer 101 applied to the surface of the heat source 301, a second infiltration layer 102 applied to the surface of the heat sink 302, and a liquid metal layer 200 in contact with the rough surface 1001 of the two infiltration layers, respectively.

[0120] In summary, the thermal interface 000 provided by the embodiments of the present application has at least the following advantages:

[0121] (1) By matching the above-mentioned infiltration layer 100 with the liquid metal layer 200 to form the thermal interface 000, compared with the high polymer-based thermal interface, the thermal interface 000 provided by the embodiments of the present application has higher thermal conductivity, can effectively fill the gap between the devices 300, such as between the heat sink and the chip, form a high-speed "source-road-load" channel, and thus obtain better heat conduction effect in actual application.

[0122] (2) The infiltration layer 100 can be formed on the surface of the device 300 by means such as acid etching, so that it has a rough surface 1001, which is beneficial to increase its surface area, and finally reduce the wetting angle (i.e. contact angle) between the liquid metal and the device 300 through capillary effect, so as to realize good thermal contact (i.e. heat conduction) between the liquid metal and the device 300, and effectively reduce the interfacial thermal resistance.

[0123] (3) The infiltration layer 100 can be formed on the surface of the device 300, that is, the infiltration layer 100 can be formed on any metal or semiconductor material in contact therewith, so as to improve the adhesion between the device 300 and the infiltration layer 100.

[0124] (4) The liquid metal and the infiltration material used both have the advantages of high thermal conductivity, non-toxicity, safety and stability, etc., so that the thermal interface 000 can be used in various products, such as data communication equipment (mobile phones, notebook computers, etc.), automobiles, civil products, lighting products, etc.

[0125] In another aspect, the embodiments of the present application also provide a method for obtaining a thermal interface, wherein the thermal interface is the thermal interface described above in the embodiments of the present application.

[0126] As shown in FIG. 1, the method for obtaining a thermal interface provided by the embodiments of the present application includes the following steps: Figure 6

[0127] Step 101: applying a layer of wetting material on the surface of the device by using the wetting material.

[0128] Step 102: roughening the surface of the layer of wetting material away from the surface of the device to form a wetting layer with a rough surface.

[0129] Step 103: contacting the rough surface of the wetting layer with a layer of liquid metal, for example, the layer of liquid metal can be applied on the rough surface of the wetting layer.

[0130] In this way, the thermal interface obtained by the embodiments of the present application includes the wetting layer and the layer of liquid metal, and the layer of liquid metal is in contact with the rough surface of the wetting layer. The layer of liquid metal includes opposite first and second surfaces, and as an example, one of the first and second surfaces of the layer of liquid metal is in contact with the rough surface of the wetting layer. As another example, the opposite two surfaces of the layer of liquid metal are in contact with the rough surfaces of two wetting layers respectively.

[0131] In the embodiments of the present application, the wetting material is capable of conducting heat, and the wetting material is also capable of promoting the solubility between the wetting layer and the layer of liquid metal. As long as the wetting material meets the above requirements, it is suitable for the present application.

[0132] For example, the wetting material includes but is not limited to at least one of In, In alloy, Cu, Cu alloy, Ni, Ni alloy, Au, Au alloy, Fe, Fe alloy.

[0133] For step 101, the layer of wetting material can be obtained by applying the wetting material on the surface of the device through a thin film deposition process. The thin film deposition process includes but is not limited to atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), and in particular, for example, plasma enhanced chemical vapor deposition (PECVD) process, magnetron sputtering, electron beam evaporation, vacuum evaporation, etc.

[0134] ​The film deposition process is selected according to the type of the infiltrating material, as long as the infiltrating layer can be tightly attached to the surface of the device.

[0135] For example, when the infiltrating material is In material, a certain thickness of In coating can be formed on the surface of the device 300 by magnetron sputtering or vacuum evaporation. Some magnetron sputtering parameters are shown in the following example data:

[0136] For example, the flow rate of the sputtering gas is 15-40 Sccm, for example, 25 Sccm; the working pressure is 0.2 pa-0.8 pa, for example, 0.4 pa; the target-substrate distance is 30 mm-60 mm, for example, 50 mm; the operating power is 120 W-160 W, for example, 40 mm; and the sputtering time is 40 min-100 min. The longer the sputtering time, the larger the area of the sputtered In coating, and even the thicker the In coating. The sputtering gas used includes but is not limited to at least one of argon Ar, krypton Kr, xenon Xe, neon Ne, and nitrogen N2. Argon Ar is selected as the magnetron sputtering working gas because it is low in price and easy to obtain.

[0137] For step 102, the surface of the infiltrating material layer away from the surface of the device is roughened. The roughening method includes but is not limited to solvent etching, electrochemical sandblasting (for example, alternating current electrolytic corrosion), chemical polishing, and plasma etching.

[0138] In the embodiments of the present application, the surface roughening method is comprehensively considered according to the type of the device and the type of the infiltrating material layer. As long as the device itself is not affected after the roughening treatment, and the desired micro-nano rough structure can be obtained on the infiltrating material layer.

[0139] In some examples, when the device is an electronic component, the surface of the infiltrating material layer can be roughened by solvent etching. In this way, by applying the corrosive solvent only to the surface of the infiltrating material layer, the infiltrating layer with a rough surface can be obtained.

[0140] The surface of the infiltrating material layer is roughened by solvent etching, including but not limited to the following operation methods:

[0141] The corrosive solvent with a set mass concentration is applied to the surface of the infiltrating material layer, and the corrosion treatment is performed for a set time to form an infiltrating layer with a rough surface. For example, the application method of the corrosive solvent can be dropwise addition, coating, soaking, etc.

[0142] The corrosive solvent includes, but is not limited to, acid, alkali, etc. For example, the surface of the infiltrating material layer can be roughened by acid corrosion. An acid solution with a set mass concentration is applied to the surface of the infiltrating material layer, and the acid corrosion treatment is performed for a set time to form an infiltrating layer with a rough surface.

[0143] In some examples, the corrosive solvent includes, but is not limited to, hydrochloric acid solution, nitric acid solution, sulfuric acid solution, hydrofluoric acid solution, etc. The mass concentration of the acid solution is adaptively selected according to the actual application requirements to ensure that the corrosion process is controllable and does not penetrate the infiltrating material layer to affect the device itself.

[0144] For example, the mass concentration of the hydrochloric acid solution suitable for the embodiments of the present application is 1.5% to 10%. The corrosion process caused by the hydrochloric acid solution with the mass concentration in the range is mild and controllable, and can form a desired microstructure on the surface of the infiltrating material layer.

[0145] The corrosion treatment time is adaptively controlled according to the thickness of the infiltrating material layer and the roughness of the rough surface formed, etc. Generally, the thicker the infiltrating material layer, the longer the corrosion treatment time, and vice versa. In the embodiments of the present application, considering that the thickness of the infiltrating layer can be 0.5 microns to 3 microns, for example, the acid corrosion, the suitable corrosion treatment time is 5 seconds to 2 minutes, for example, 8 seconds, 10 seconds, 15 seconds, 30 seconds, 50 seconds, 1 minute, 1.5 minutes, etc.

[0146] Before and after the roughening treatment of the surface of the infiltrating material layer, the surface of the infiltrating material layer or the obtained infiltrating layer can be cleaned, for example, by using alcohol wiping.

[0147] In some possible examples, the infiltrating layer is obtained by the following operations, and the operation steps include:

[0148] (1) An infiltrating material layer is coated on the surface of the device by magnetron sputtering or vacuum evaporation technology, and the thickness of the infiltrating material layer is 0.5 microns to 3 microns. The infiltrating material includes, but is not limited to, at least one of In, In alloy, Cu, Cu alloy, Ni, Ni alloy, Au, Au alloy, Fe, and Fe alloy.

[0149] (2) The treated surface of the obtained infiltrating material layer is soaked in a hydrochloric acid solution or the hydrochloric acid solution is added dropwise on the treated surface of the infiltrating material layer, and the acid corrosion treatment is performed for 5 seconds to 2 minutes to obtain an infiltrating layer on the surface of the device. The concentration of the hydrochloric acid solution is 1.5% to 10%.

[0150] According to the above operation steps, when the infiltrating material is In and the acid etching treatment time is 1 minute, an In material infiltrating layer is obtained, and the wettability between the In material infiltrating layer and the gallium-based liquid metal is tested. The test results show that the wetting angle (i.e. the contact angle) between the In material infiltrating layer and the gallium-based liquid metal is less than 60°, which indicates that the two have good wettability.

[0151] As a comparison, the wettability between the following types of surfaces and the gallium-indium-tin liquid metal is also tested in the embodiments of the present application:

[0152] (1) a silicon coating layer surface formed by elemental silicon; (2) a surface of an In coating layer coated on the surface of elemental silicon, wherein the surface of the In coating layer is not subjected to acid etching treatment; and (3) an acid-etched rough surface of an In coating layer coated on the surface of elemental silicon, that is, the acid-etched surface of the In coating layer is subjected to acid etching treatment and is a rough surface.

[0153] The surface morphology of the acid-etched rough surface of the In coating layer (3) is tested by electron microscope scanning in the embodiments of the present application, and the corresponding electron microscope image can be seen from Figure 7 , and it can be known from the surface morphology of the rough surface shown in Figure 7 that the rough surface is a micron-scale floating protrusion surface with unevenness.

[0154] The surface roughness of the acid-etched rough surface of the In coating layer (3) is also tested by using a Mitutoyo SJ-301 roughness tester in the embodiments of the present application, and a line scanning method is adopted, and the sampling length of the scanning is 4 microns, and the corresponding surface roughness data representation image can be seen from Figure 8 , and the depth fluctuation change rule of the uneven microstructure on the rough surface can be directly observed from Figure 8 . As shown in A of Figure 8 , before the In coating layer is subjected to acid etching roughening treatment, the average surface roughness of the corresponding rough surface is about 4-6 microns, and the density (i.e. the fluctuation density) of the uneven microstructure on the surface is relatively low, and the specific surface area is relatively small. As shown in B of Figure 8 , after the In coating layer is subjected to acid etching roughening treatment, the average surface roughness of the corresponding rough surface is about 2.5 microns, and it can be clearly observed that the density of the uneven microstructure on the rough surface is significantly improved, so that the specific surface area of the rough surface is greatly improved, which shows that after the surface acid etching treatment described in the present application, the rough surface with a microstructure distribution of sub-micron scale, even nanometer scale, which is expected in the present application, is formed on the In coating layer, which is beneficial to greatly optimizing the wettability between the In infiltrating layer and the liquid metal layer.

[0155] Referring to Figure 9After adding gallium indium tin liquid metal to the silicon coating surface of (1) elemental silicon, the wetting angle between the two was measured to be around 155°.

[0156] See Figure 10 After the liquid metal gallium indium tin was dropped onto the surface of the (2)In coating, the wetting angle between the two was measured to be around 138°.

[0157] See Figure 11 After adding liquid gallium indium tin metal to the acid-etched rough surface of (3)In coating, the wetting angle between the two was measured to be between 52° and 56°.

[0158] It is evident that acid etching of the In coating surface can significantly reduce the contact angle between it and the liquid gallium indium tin metal, thereby significantly improving the wettability between the two.

[0159] The thermal interface provided in this application uses a material with a certain degree of miscibility with liquid metal as the wetting material. Furthermore, the surface of the wetting material layer is roughened by acid etching, thereby forming a micro-nano-scale protruding surface, significantly increasing the specific surface area. Simultaneously, a capillary effect is introduced to a certain extent, thus greatly optimizing the wettability between the wetting layer and the liquid metal layer. In particular, the method for obtaining this wetting layer is simple to operate, low in cost, and easy to scale up for application.

[0160] In another aspect, embodiments of this application also provide an electronic product, which includes a thermal interface 000 and a device 300. The thermal interface 000 is as described above in embodiments of this application, and the thermal interface 000 is located on the surface of the device 300.

[0161] For a description of the thermal interface 000, please refer to the relevant explanation in the thermal interface 000 content section above. It will not be described again here. In other words, the thermal interface 000 involved in the embodiments of this application is applicable to the electronic product.

[0162] Based on the use of this thermal interface 000, the electronic product provided in this application embodiment not only has excellent heat dissipation performance, but also avoids the problem of high-temperature overflow of liquid metal.

[0163] In some possible implementations, device 300 includes: heat source 301 and / or heat dissipation source 302.

[0164] In some examples, as shown in the appendix Figure 3 As shown, the device 300 includes a heat source 301, and the thermal interface 000 may include: a wetting layer 100 applied to the surface of the heat source 301, and a liquid metal layer 200 in contact with the rough surface 1001 of the wetting layer 100.

[0165] In some examples, as shown in FIG. 3A, the device 300 includes a heat source 301 and a heat sink 302, and the thermal interface 000 includes a first wetting layer 101, a liquid metal layer 200, and a second wetting layer 102. The first wetting layer 101 is disposed on a surface of the heat source 301, and a rough surface 1001 of the first wetting layer 101 is in contact with a first surface of the liquid metal layer 200. The second wetting layer 102 is disposed on a surface of the heat sink 302, and a rough surface 1001 of the second wetting layer 102 is in contact with a second surface of the liquid metal layer 200. That is, the liquid metal layer 200 is disposed between the first wetting layer 101 and the second wetting layer 102. Figure 4 The thermal interface 000 can include: a wetting layer 100 applied to a surface of the heat sink 302, and a liquid metal layer 200 in contact with a rough surface 1001 of the wetting layer 100.

[0166] In some examples, as shown in FIG. 3A, the device 300 includes a heat source 301 and a heat sink 302, and the thermal interface 000 includes a first wetting layer 101, a liquid metal layer 200, and a second wetting layer 102. The first wetting layer 101 is disposed on a surface of the heat source 301, and a rough surface 1001 of the first wetting layer 101 is in contact with a first surface of the liquid metal layer 200. The second wetting layer 102 is disposed on a surface of the heat sink 302, and a rough surface 1001 of the second wetting layer 102 is in contact with a second surface of the liquid metal layer 200. That is, the liquid metal layer 200 is disposed between the first wetting layer 101 and the second wetting layer 102. Figure 5 The thermal interface 000 can include: a first wetting layer 101 disposed on a surface of the heat source 301, a liquid metal layer 200, and a second wetting layer 102 disposed on a surface of the heat sink 302. A rough surface 1001 of the first wetting layer 101 is in contact with a first surface of the liquid metal layer 200, and a rough surface 1001 of the second wetting layer 102 is in contact with a second surface of the liquid metal layer 200. The thermal interface 000 can include: a first wetting layer 101 disposed on a surface of the heat source 301, a liquid metal layer 200, and a second wetting layer 102 disposed on a surface of the heat sink 302. A rough surface 1001 of the first wetting layer 101 is in contact with a first surface of the liquid metal layer 200, and a rough surface 1001 of the second wetting layer 102 is in contact with a second surface of the liquid metal layer 200.

[0167] In some possible implementations, the heat source 301 includes but is not limited to: an electronic chip, an integrated circuit chip, etc.; and the heat sink 302 includes but is not limited to: a heat sink such as a liquid cooling plate, a VC heat sink, etc. In some possible implementations, the heat source 301 includes but is not limited to: an electronic chip, an integrated circuit chip, etc.; and the heat sink 302 includes but is not limited to: a heat sink such as a liquid cooling plate, a VC heat sink, etc.

[0168] The electronic product provided by the embodiments of the present application is particularly suitable for use as a high-energy-density electronic device product such as a chip, an insulated gate bipolar transistor (IGBT), etc. The electronic product provided by the embodiments of the present application is particularly suitable for use as a high-energy-density electronic device product such as a chip, an insulated gate bipolar transistor (IGBT), etc.

[0169] In another aspect, the embodiments of the present application further provide a method for facilitating heat conduction between a device and a liquid metal layer, as shown in FIG. 3B, the method includes the following steps: Figure 12 The method includes the following steps:

[0170] Step 201: applying a wetting layer to a surface of a device, the wetting layer having a rough surface.

[0171] Step 202: contacting the rough surface of the wetting layer with a liquid metal layer to form a thermal interface, wherein the thermal interface is as described above.

[0172] By applying the wetting layer to the surface of the device and contacting the rough surface of the wetting layer with the liquid metal layer, the wettability between the wetting layer and the liquid metal layer is stronger than the wettability between the surface of the device and the liquid metal layer. On the other hand, the rough surface of the wetting layer has a microstructure, which can further improve the wettability between the wetting layer and the liquid metal layer through capillary effect when the rough surface of the wetting layer is in contact with the liquid metal layer. Ultimately, the heat conduction between the device and the liquid metal layer is improved, and the thermal resistance between the interfaces is reduced.

[0173] For example, for step 201, a wetting material can be used, a layer of the wetting material is applied on the surface of the device by a thin film deposition process, and then the surface of the layer of the wetting material away from the surface of the device is roughened to form a wetting layer with a rough surface.

[0174] The thin film deposition process includes but is not limited to atomic layer deposition, physical vapor deposition, chemical vapor deposition, and in particular, for example, plasma enhanced chemical vapor deposition process, magnetron sputtering, electron beam evaporation, etc. The specific thin film deposition process used is adaptively selected according to the specific type of wetting material, as long as the wetting layer can be closely attached to the surface of the device.

[0175] The wetting material includes but is not limited to at least one of In, In alloy, Cu, Cu alloy, Ni, Ni alloy, Au, Au alloy, Fe, Fe alloy.

[0176] The roughening treatment of the surface of the wetting material layer includes but is not limited to solvent etching, electrochemical sandblasting (such as alternating current electrolytic corrosion), chemical polishing, plasma etching, laser etching, etc.

[0177] The surface of the wetting material layer can be roughened by solvent etching, so that by applying a corrosive solvent only to the surface of the wetting material layer, a wetting layer with a rough surface can be obtained.

[0178] The roughening of the surface of the wetting material layer by solvent etching includes but is not limited to the following operations:

[0179] A corrosive solvent with a set mass concentration is applied to the surface of the wetting material layer, and the surface is etched for a set time to form a wetting layer with a rough surface. For example, the corrosive solvent can be added dropwise, coated, soaked, etc.

[0180] The above-mentioned corrosive solvent includes but is not limited to acid solution, alkali solution, etc. For example, the surface of the wetting material layer can be roughened by acid etching, an acid solution with a set mass concentration is applied to the surface of the wetting material layer, and the surface is etched for a set time to form a wetting layer with a rough surface.

[0181] In some examples, the corrosive solvent includes but is not limited to hydrochloric acid solution, nitric acid solution, sulfuric acid solution, hydrofluoric acid solution, etc. The mass concentration of these acid solutions is adaptively selected according to the actual application requirements to ensure that the etching process is controllable and does not penetrate the wetting material layer to affect the device itself.

[0182] For example, the hydrochloric acid solution has a mass concentration of 1.5% to 10%. The corrosion process caused by the hydrochloric acid solution in the mass concentration range is mild and controllable, and the desired microstructure can be formed on the surface of the wetting material layer.

[0183] The corrosion treatment time is adaptively controlled according to the thickness of the wetting material layer and the roughness of the formed rough surface. Generally, the thicker the wetting material layer, the longer the corrosion treatment time, and vice versa. In the embodiments of the present application, the thickness of the wetting layer can be 0.5 microns to 3 microns. For example, the acid corrosion treatment time is 5 seconds to 2 minutes, for example, 8 seconds, 10 seconds, 15 seconds, 30 seconds, 50 seconds, 1 minute, 1.5 minutes, etc.

[0184] Before and after the roughening treatment of the surface of the wetting material layer, the surface of the wetting material layer or the obtained wetting layer can be cleaned, for example, by using alcohol wiping.

[0185] In another aspect, the embodiments of the present application also provide a method for thermally abutting a heat source to a heat dissipation source, as shown in FIG. 8, the method comprises the following steps: Figure 13

[0186] Step 301, applying a first wetting layer on the surface of the heat source, the first wetting layer having a rough surface; and applying a second wetting layer on the surface of the heat dissipation source, the second wetting layer having a rough surface.

[0187] Step 302, applying a liquid metal layer between the rough surface of the first wetting layer and the rough surface of the second wetting layer, so that the two surfaces of the liquid metal layer are in contact with the rough surfaces of the corresponding wetting layers respectively, forming a thermal interface.

[0188] The thermal interface is the thermal interface described above in the embodiments of the present application.

[0189] In some possible implementations, the heat source includes but is not limited to an electronic chip, an integrated circuit chip, etc.; and the heat dissipation source includes but is not limited to a heat sink, such as a liquid cooling plate, a VC heat sink, etc.

[0190] ​The rough surface of the wetting layer is in contact with the liquid metal layer, the wetting between the wetting layer and the liquid metal layer is stronger than the wetting between the surface of the heat source or the heat dissipation source and the liquid metal layer, on the other hand, the rough surface of the wetting layer has a microstructure, which can further improve the wetting between the wetting layer and the liquid metal layer through capillary effect when in contact with the liquid metal layer, ultimately improving the heat conduction between the heat source and the liquid metal layer and the heat dissipation source and the liquid metal layer, reducing the thermal resistance between the interfaces, and promoting the thermal abutment between the heat source and the heat dissipation source.

[0191] For example, for step 301, a wetting material can be used to apply a wetting material layer on the surface of the heat source or the heat dissipation source by a thin film deposition process, and then the surface of the wetting material layer away from the surface of the heat source or the heat dissipation source is roughened to form a wetting layer with a rough surface.

[0192] The thin film deposition process includes but is not limited to atomic layer deposition, physical vapor deposition, chemical vapor deposition, and in particular, for example, plasma enhanced chemical vapor deposition process, magnetron sputtering, electron beam evaporation, etc. According to the specific type of wetting material, the specific thin film deposition process used is adaptively selected as long as the wetting layer can be closely attached to the surface of the heat source or the heat dissipation source.

[0193] The wetting material includes but is not limited to at least one of In, In alloy, Cu, Cu alloy, Ni, Ni alloy, Au, Au alloy, Fe, Fe alloy.

[0194] The roughening treatment of the surface of the wetting material layer includes but is not limited to solvent etching, electrochemical sandblasting (such as alternating current electrolytic corrosion method), chemical polishing, plasma etching, laser etching, etc.

[0195] The surface of the wetting material layer can be roughened by solvent etching, so that by applying a corrosive solvent only on the surface of the wetting material layer, a wetting layer with a rough surface can be obtained.

[0196] The roughening treatment of the surface of the wetting material layer by solvent etching includes but is not limited to the following operation modes:

[0197] A corrosive solvent with a set mass concentration is applied to the surface of the wetting material layer, and the corrosion treatment is performed for a set time to form a wetting layer with a rough surface. For example, the application of the corrosive solvent can be dropwise, coating, soaking, etc.

[0198] The corrosive solvent includes, but is not limited to, acid, alkali, etc. For example, the surface of the infiltrating material layer can be roughened by acid corrosion. An acid solution with a certain mass concentration is applied to the surface of the infiltrating material layer, and the acid corrosion treatment is performed for a certain time to form an infiltrating layer with a rough surface.

[0199] In some examples, the corrosive solvent includes, but is not limited to, hydrochloric acid solution, nitric acid solution, sulfuric acid solution, hydrofluoric acid solution, etc. The mass concentration of the acid solution is adaptively selected according to the actual application requirement to ensure that the corrosion process is controllable and does not penetrate the infiltrating material layer to affect the heat source or the heat sink itself.

[0200] For example, the mass concentration of the hydrochloric acid solution suitable for the embodiments of the present application is 1.5% to 10%. The corrosion process caused by the hydrochloric acid solution with the mass concentration in the range is mild and controllable, and the desired microstructure can be formed on the surface of the infiltrating material layer.

[0201] The corrosion treatment time is adaptively controlled according to the thickness of the infiltrating material layer and the roughness of the rough surface formed, etc. Generally, the thicker the infiltrating material layer, the longer the corrosion treatment time, and vice versa. In the embodiments of the present application, the thickness of the infiltrating layer can be 0.5 microns to 3 microns. For example, the corrosion treatment time suitable for the acid corrosion is 5 seconds to 2 minutes, such as 8 seconds, 10 seconds, 15 seconds, 30 seconds, 50 seconds, 1 minute, 1.5 minutes, etc.

[0202] Before and after the roughening treatment of the surface of the infiltrating material layer, the surface of the infiltrating material layer or the obtained infiltrating layer can be cleaned, for example, by using alcohol wiping.

[0203] For step 302, the liquid metal layer is applied between the rough surface of the first infiltrating layer and the rough surface of the second infiltrating layer, so that the two surfaces of the liquid metal layer are in contact with the rough surfaces of the corresponding infiltrating layers, which can be achieved by one of the following methods:

[0204] In some possible examples, the liquid metal layer is first applied to the rough surface of the first infiltrating layer, and then the rough surface of the second infiltrating layer is in contact with the surface of the liquid metal layer.

[0205] In some possible examples, the liquid metal layer is first applied to the rough surface of the second infiltrating layer, and then the rough surface of the first infiltrating layer is in contact with the surface of the liquid metal layer.

[0206] The present application will be further described by specific embodiments:

[0207] Embodiment 1

[0208] The embodiment 1 provides a thermal interface, which is obtained by the following method:

[0209] A high-purity In target material is selected, and an In coating is coated on a Si material surface of a device by magnetron sputtering, and the thickness of the In coating is 1.2 microns.

[0210] Then, the In coating is wiped by alcohol, and dilute hydrochloric acid with a mass concentration of 3 % is coated on the In coating, and the In coating is subjected to acid etching treatment, and the treatment time is 20 seconds, so that the In coating with a rough surface is obtained as the thermal interface.

[0211] After the acid etching is completed, the rough surface of the In coating is cleaned by alcohol again, and then an immersion test is conducted by using a gallium-indium-tin liquid metal, and the immersion angle of the gallium-indium-tin liquid metal on the rough surface of the In coating is recorded, and the specific test results are shown in Table 1.

[0212] Embodiment 2

[0213] The embodiment 2 provides a thermal interface, which is obtained by the following method:

[0214] A high-purity In target material is selected, and an In coating is coated on a Cu material surface of a device by magnetron sputtering, and the thickness of the In coating is 2 microns.

[0215] Then, the In coating is wiped by alcohol, and dilute hydrochloric acid with a mass concentration of 2 % is coated on the In coating, and the In coating is subjected to acid etching treatment, and the treatment time is 80 seconds, so that the In coating with a rough surface is obtained as the thermal interface.

[0216] After the acid etching is completed, the rough surface of the In coating is cleaned by alcohol again, and then an immersion test is conducted by using a gallium-indium-tin liquid metal, and the immersion angle of the gallium-indium-tin liquid metal on the rough surface of the In coating is recorded, and the specific test results are shown in Table 1.

[0217] Embodiment 3

[0218] The embodiment 3 provides a thermal interface, which is obtained by the following method:

[0219] A high-purity In target material is selected, and an In coating is coated on a Si material surface of a device by magnetron sputtering, and the thickness of the In coating is 0.5 microns.

[0220] Then, the In coating is wiped by alcohol, and dilute hydrochloric acid with a mass concentration of 1.5 % is coated on the In coating, and the In coating is subjected to acid etching treatment, and the treatment time is 95 seconds, so that the In coating with a rough surface is obtained as the thermal interface.

[0221] After acid etching, the rough surface of the In coating is cleaned again with alcohol, and then the wettability test is performed using gallium-indium-tin liquid metal, and the wetting angle of the gallium-indium-tin liquid metal on the rough surface of the In coating is recorded. The specific test results are shown in Table 1.

[0222] Example 4

[0223] This example 4 provides a thermal interface obtained by the following method:

[0224] A high-purity In target material is selected, and an In coating is coated on the surface of a device made of Ni material by magnetron sputtering. The thickness of the In coating is 1.5 microns.

[0225] Then, the In coating is wiped with alcohol, and a dilute hydrochloric acid with a mass concentration of 2.5% is coated on the In coating for acid etching treatment. The treatment time is 45 seconds, and an In coating with a rough surface is obtained as a thermal interface.

[0226] After acid etching, the rough surface of the In coating is cleaned again with alcohol, and then the wettability test is performed using gallium-indium-tin liquid metal, and the wetting angle of the gallium-indium-tin liquid metal on the rough surface of the In coating is recorded. The specific test results are shown in Table 1.

[0227] Test Example

[0228] The gallium-indium-tin liquid metal is dropped on the surface of a silicon coating formed by elemental silicon for wettability test. The specific test results are shown in Table 1.

[0229] Table 1

[0230]

[0231] As shown in Table 1, the method provided by the present application can obtain a thermal interface with good wettability with gallium-based liquid metal, and the wetting angle between the two is significantly reduced compared to the silicon coating without any treatment, which significantly improves the wettability between the wetting layer and the liquid metal layer, so that the combination of the wetting layer and the liquid metal layer can be used in the field of high-density heat dissipation of chips, IGBTs, etc.

[0232] The thermal resistance of electronic products using the thermal interfaces provided in examples 1-4 is tested. In the electronic products, the device includes an electronic chip, a heat sink, and a thermal interface, and the thermal interface is arranged on the electronic chip and the heat sink. The thermal resistance test refers to the test method specified in the thermal resistance test standard ASTM D5470. The specific test results are shown in Table 1.

[0233] As can be seen from Table 1, the thermal resistance of the electronic product using the thermal interface provided by Examples 1-4 is significantly reduced relative to the comparative example, which means that the heat conduction performance of the electronic product is significantly improved, and the heat conduction efficiency is improved.

[0234] In the embodiments of the present application, the terms "first" and "second" are only for descriptive purposes, and cannot be understood or implied to indicate or imply relative importance. The term "a plurality of" refers to two or more, unless otherwise explicitly limited.

[0235] The term "and / or" in the embodiments of the present application only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in this paper generally represents that the associated objects before and after are in an "or" relationship.

[0236] The above is only to facilitate those skilled in the art to understand the technical solutions of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A thermal interface, characterized in that, The thermal interface (000) comprises: an infiltrating layer (100) and a liquid metal layer (200), the infiltrating layer (100) comprises a micro-nano scale rough surface (1001); The infiltrating layer (100) is located between the device (300) and the liquid metal layer (200), and the rough surface (1001) of the infiltrating layer (100) is in contact with the liquid metal layer (200); The raw material for preparing the liquid metal layer (200) is gallium Indium alloy, gallium Tin alloy, gallium Indium Tin alloy, indium Gallium Tin Bismuth alloy, indium Tin Bismuth alloy, gallium Bismuth Indium Thallium Tin Copper alloy, gallium Bismuth Indium Cesium alloy, gallium Bismuth Indium Molybdenum alloy or gallium Bismuth Indium Cesium Molybdenum alloy; The infiltrating layer (100) is prepared by using an infiltrating material, and the infiltrating material is at least one selected from indium and its alloy.

2. The thermal interface of claim 1, wherein, The surface roughness of the rough surface (1001) of the infiltrating layer (100) is less than or equal to 3 microns.

3. The thermal interface of claim 1, wherein, The infiltrating material is mutually soluble with the liquid metal layer (200), and the infiltrating material has thermal conductivity.

4. The thermal interface of claim 1, wherein, The thickness of the infiltrating layer (100) is 0.5 microns-3 microns.

5. The thermal interface of any of claims 1-4, wherein, The preparation raw material of the liquid metal layer (200) further comprises: an auxiliary material, the auxiliary material is used to improve at least one of the following properties of the liquid metal layer (200): thermal conductivity, corrosion resistance, wettability and viscosity.

6. The thermal interface of claim 5, wherein, The auxiliary material is a thermal conductive material.

7. The thermal interface of claim 6, wherein, The thermal conductive material is at least one selected from diamond powder, SiC powder, AlN powder, W metal powder, Cu metal powder and Ni metal powder.

8. The thermal interface of claim 1, wherein, The infiltrating layer (100) has two layers, and the opposite two surfaces of the liquid metal layer (200) are respectively in contact with the rough surface (1001) of one of the infiltrating layers (100).

9. The thermal interface of claim 1, wherein, The device (300) comprises: a heat source (301) and / or a heat dissipation source (302).

10. A method of acquiring a thermal interface, characterized by, The thermal interface is the thermal interface of any one of claims 1-9; The method for obtaining the thermal interface comprises: using an infiltrating material to apply an infiltrating material layer on the surface of the device (300); The surface of the infiltrating material layer away from the device (300) is roughened to form the infiltrating layer (100) with a rough surface (1001); The rough surface (1001) of the infiltrating layer (100) is in contact with the liquid metal layer (200).

11. The heat interface acquisition method of claim 10, wherein, The infiltrating material layer is applied on the surface of the device (300) by a thin film deposition process.

12. The method of acquiring a thermal interface according to claim 10, wherein, The surface of the infiltrating material layer is roughened by a solvent etching method.

13. The method of acquiring a thermal interface according to claim 12, wherein, The roughening of the surface of the infiltrating material layer by the solvent etching method comprises: An etching solution with a set mass concentration is applied to the surface of the infiltrating material layer for a set etching time to form the infiltrating layer (100) with the rough surface (1001).

14. The heat interface acquisition method of claim 13, wherein, The etching solution is a hydrochloric acid solution, and the mass concentration of the hydrochloric acid solution is 1.5%-10%.

15. The method of claim 13, wherein: The etching time is 5 seconds-2 minutes.

16. An electronic product, characterized by The electronic product comprises: a thermal interface (000) and a device (300); The thermal interface (000) is the thermal interface of any one of claims 1-9, and the thermal interface (000) is located on the surface of the device (300).

17. The electronic product of claim 16, wherein, The device (300) comprises: a heat source (301) and / or a heat dissipation source (302).

18. The electronic product of claim 17, wherein, The device (300) comprises a heat source (301) and a heat sink (302); The thermal interface (000) comprises a first wetting layer (101), a liquid metal layer (200) and a second wetting layer (102); The first wetting layer (101) is located on the surface of the heat source (301), and the rough surface (1001) of the first wetting layer (101) is in contact with the first surface of the liquid metal layer (200); The second wetting layer (102) is located on the surface of the heat sink (302), and the rough surface (1001) of the second wetting layer (102) is in contact with the second surface of the liquid metal layer (200).

19. A method for promoting heat transfer between a device and a layer of liquid metal, characterized by, The method comprises: applying a wetting layer (100) on the surface of the device (300), the wetting layer (100) having a rough surface (1001); The rough surface (1001) of the wetting layer (100) is in contact with the liquid metal layer (200) to form a thermal interface (000); The thermal interface (000) is the thermal interface according to any one of claims 1-9.

20. A method for thermally abutting a heat source to a heat sink, characterized by, The method comprises: applying a first wetting layer (101) on the surface of the heat source (301), the first wetting layer (101) having a rough surface (1001); and applying a second wetting layer (102) on the surface of the heat sink (302), the second wetting layer (102) having a rough surface (1001); The rough surface (1001) of the first wetting layer (101) and the rough surface (1001) of the second wetting layer (102) are in contact with the two surfaces of the liquid metal layer (200) respectively to form a thermal interface (000); The thermal interface (000) is the thermal interface according to any one of claims 1-9.

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