Gallium oxide high-power device with efficient comprehensive heat dissipation performance and manufacturing method of gallium oxide high-power device

Abstract

The invention provides a gallium oxide high-power device with efficient comprehensive heat dissipation performance and a manufacturing method of the gallium oxide high-power device. According to the invention, by thinning the substrate, the thermal resistance when heat flows through the substrate is reduced, the structure is more compact, and the packaging volume is reduced. And a double-sided packaging structure is used, and the anode and the cathode of the chip are simultaneously connected with the substrate by using solder, so that high heat conduction paths on the upper side and the lower side of the device are provided, an efficient double-sided heat dissipation channel is formed, and the junction-to-case thermal resistance and the junction temperature of the device are remarkably reduced. And meanwhile, the high-thermal-conductivity plastic packaging material is used, so that the heat dissipation capability is improved, and the packaging material is flexible after being cured, can effectively absorb and buffer thermal stress generated by mismatching of thermal expansion coefficients among materials, and is suitable for protecting ultrathin and brittle gallium oxide chips and preventing the ultrathin and brittle gallium oxide chips from being fractured and layered under stress. The device package can have lower junction temperature and thermal resistance and low stress, so that the gallium oxide device with excellent performance is obtained.

Description

Technical Field

[0001] This invention proposes a gallium oxide high-power device with efficient comprehensive heat dissipation performance and its fabrication method, which relates to the field of power semiconductor technology. Background Technology

[0002] Wide bandgap semiconductor materials, such as silicon carbide (SiC) and gallium nitride (GaN), have become core materials for manufacturing next-generation high-efficiency, high-power-density power devices due to their excellent material properties. In recent years, gallium oxide (Ga2O3), as a representative of ultra-wide bandgap semiconductor materials, has a Baliga figure of merit far exceeding that of SiC and GaN, exhibiting higher critical breakdown field strength and theoretically lower conduction loss. It has shown great potential in high-voltage, high-power applications and is considered one of the disruptive materials for future power electronics.

[0003] However, gallium oxide devices generate extremely high heat flux densities when operating at high voltage and high current. Gallium oxide itself has low thermal conductivity (only 10-30 W / m·K), making it difficult to quickly and effectively dissipate the heat generated in the active region of the device. If heat accumulates, the junction temperature will rise sharply, leading to performance degradation, decreased reliability, and even device failure. Therefore, traditional packaging technologies cannot meet the heat dissipation requirements of gallium oxide devices, and developing ultra-low thermal resistance packaging solutions is a primary prerequisite for promoting their application. Summary of the Invention

[0004] In view of this, to fill the gaps and deficiencies in the existing technology, this invention proposes a gallium oxide high-power device with efficient comprehensive heat dissipation performance and its fabrication method. This invention reduces the substrate thickness through mechanical thinning and polishing, thereby reducing the thermal resistance of heat passing through the substrate region. Simultaneously, it employs a double-sided packaging structure to improve the heat dissipation capability of the device from the heat-generating junction to the upper and lower surfaces of the package. Furthermore, it uses a high thermal conductivity molding material, whose thermal conductivity (≥4.2 W / m·K) is higher than that of common epoxy resins and silicone gels, and it remains flexible after curing. Therefore, this device exhibits lower junction temperature, lower thermal resistance, and lower stress.

[0005] This invention proposes a high-power gallium oxide device with efficient overall heat dissipation performance and its fabrication method, including the following:

[0006] This invention proposes a high-power gallium oxide device with efficient overall heat dissipation performance. Its features include: using a gallium oxide wafer fabricated with a substrate-thinned chip (achieved through mechanical thinning and polishing to reduce substrate thickness) to reduce thermal resistance through the substrate region; employing a double-sided packaging structure and a molding compound with high thermal conductivity to improve heat conduction efficiency; ultimately enhancing the overall heat dissipation performance of the high-power gallium oxide device.

[0007] The present invention proposes a gallium oxide high-power device with efficient comprehensive heat dissipation performance, which includes, from bottom to top, a base plate, a bottom insulating ceramic layer, an anode substrate, an anode pin insulating terminal, a cathode pin insulating terminal, a cathode substrate, a top insulating ceramic layer, a top cover plate, a molding compound, a frame, a cathode solder layer, a chip, an anode solder layer, an anode pin, and a cathode pin.

[0008] The chip described therein is made from gallium oxide wafers through thinning and polishing;

[0009] The anode substrate is used to connect the electrodes of the chip, and the anode substrate is fixed to the anode pins, which are used to connect to external circuits.

[0010] The cathode substrate is used to connect the electrodes of the chip. The cathode substrate is fixed to the cathode pins, and the cathode pins are used to connect to external circuits.

[0011] The anode insulating terminal is fixed together with the anode pin and fixed to the frame to achieve insulation;

[0012] The cathode insulating terminal is fixed together with the cathode pin and fixed to the frame to achieve insulation;

[0013] The anode substrate is insulated from the base plate by a bottom insulating ceramic layer;

[0014] The cathode substrate is insulated from the top cover plate by a top insulating ceramic layer;

[0015] The molding compound occupies the largest volume inside the gallium oxide high-power device, filling and immersing the chip and all bottom insulating ceramic layers, top insulating ceramic layers, anode substrate, cathode substrate, cathode solder layer and anode solder layer, while expelling air from inside the device.

[0016] Furthermore, the chip is made by thinning and polishing a gallium oxide wafer to below 100μm; the back metallization layer of the gallium oxide wafer after substrate thinning and polishing is a Ti / Au or Ti / Ag composite metal layer.

[0017] Furthermore, the bottom insulating ceramic layer is made of at least one of alumina, aluminum nitride, silicon nitride, and beryllium oxide ceramics; the top insulating ceramic layer is made of at least one of alumina, aluminum nitride, silicon nitride, and beryllium oxide ceramics.

[0018] Furthermore, the anode solder layer includes a tin-based solder layer or a sintered silver solder layer; the cathode solder layer includes a tin-based solder layer or a sintered silver solder layer.

[0019] Furthermore, the molding compound is a high thermal conductivity molding compound, wherein the thermal conductivity of the molding compound is ≥4.2W / m·K; wherein the molding compound is flexible after curing.

[0020] This invention proposes a method for fabricating a gallium oxide high-power device with efficient overall heat dissipation performance, used to fabricate a gallium oxide high-power device with efficient overall heat dissipation performance as described in any one of the present invention; characterized by comprising the following:

[0021] Step S1: Select a gallium oxide wafer with a completed front-side structure;

[0022] Step S2: Spin-coat photoresist on the front side of the gallium oxide wafer for protection, and fix the front side of the device to the glass plate with heat release tape or wax;

[0023] Step S3: Use a thinning machine to rapidly mechanically thin the substrate of the gallium oxide wafer to below 100 μm;

[0024] Step S4: Rough polish the substrate surface of the thinned gallium oxide wafer;

[0025] Step S5: Perform fine polishing on the substrate surface of the gallium oxide wafer after rough polishing;

[0026] Step S6: Remove surface contaminants from the front side of the wafer;

[0027] Step S7: Deposit metal on the surface of the gallium oxide substrate using evaporation or sputtering processes to form cathode metal;

[0028] Step S8: Divide the thinned gallium oxide wafer to separate individual gallium oxide chips;

[0029] Step S9: Mount the gallium oxide power chip anode to the designated position on the anode substrate using the anode solder layer;

[0030] Step S10: Mount the gallium oxide power chip cathode to the designated position on the cathode substrate using a cathode solder layer;

[0031] Step S11: Inject molding compound into the mold cavity where the chip and other structures have been placed, so that it completely covers the gallium oxide power chip, solder, substrate, and ceramic.

[0032] Step S12: Curing is performed at a preset temperature and pressure to form the molding compound;

[0033] Step S13: Weld the top cover plate.

[0034] Further, the spin coating is characterized by: using a spin coater, first depositing at a speed of 200-800 rpm for 8-12 seconds; then increasing the speed to 500-1500 rpm for 30-90 seconds.

[0035] The thinning speed of the aforementioned thinning machine is 6 μm / min;

[0036] The rough polishing of the thinned substrate surface includes:

[0037] Use either alumina polishing slurry or diamond polishing slurry, and a polyurethane soft polishing pad. The rough polishing speed is 60 rpm.

[0038] Furthermore, the surface stain removal treatment of the device includes: immersing the device in an organic wax remover, a cleaning agent, and deionized water in sequence for ultrasonic cleaning for 3-5 minutes each, and then drying the cleaned device with nitrogen gas.

[0039] The method of depositing metal on the surface of gallium oxide substrate using evaporation or sputtering processes includes depositing a metal layer using one or more sputtering processes such as magnetron sputtering, thermal evaporation, and electron beam evaporation.

[0040] Furthermore, the dicing of the thinned gallium oxide wafer in step S8 includes using any one of the following processes: dicing or laser cutting.

[0041] Furthermore, the molding compound mentioned above is a molding compound with boron nitride / aluminum nitride filler or LMP. Fill Any one of them.

[0042] The present invention has the following advantages:

[0043] One approach is to thin the substrate to reduce the thermal resistance as heat flows through it, while also making the structure more compact and reducing the package size.

[0044] Secondly, the use of a double-sided packaging structure provides high thermal conductivity paths on both the top and bottom sides of the device, forming an efficient double-sided heat dissipation channel, which significantly reduces the junction-case thermal resistance and junction temperature of the device.

[0045] Third, the use of high thermal conductivity molding compound improves heat dissipation capacity, and after curing, it is flexible and can effectively absorb and buffer thermal stress caused by the mismatch of thermal expansion coefficients between materials. It is particularly suitable for protecting ultra-thin and brittle gallium oxide chips and preventing them from cracking and delaminating under stress. Attached Figure Description

[0046] Figure 1 This is a cross-sectional schematic diagram of the present invention.

[0047] Figure 2 This is a detailed process preparation diagram of the present invention.

[0048] Figure 3 This is a schematic diagram of the external structure of the present invention.

[0049] Figure 4 This is a schematic diagram of the internal structure of the present invention.

[0050] Figure 5 This is an exploded view of the structure of the present invention.

[0051] Figure 6 This is a comparison diagram of the junction temperature and thermal resistance of a comprehensive heat dissipation improvement method for gallium oxide high-power devices according to the present invention with that of conventional structure packaging.

[0052] Wherein: 1-bottom plate layer; 2-bottom insulating ceramic layer; 3-anode substrate; 4-anode pin insulating terminal; 5-cathode pin insulating terminal; 6-cathode substrate; 7-top insulating ceramic layer; 8-top cover plate; 9-molding material; 10-frame; 11-cathode solder layer; 12-chip; 13-anode solder layer; 14-anode pin; 15-cathode pin. Detailed Implementation

[0053] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0054] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0055] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0056] like Figures 1 to 6 As shown, this invention proposes a high-power gallium oxide device with efficient overall heat dissipation performance and its fabrication method, characterized by comprising the following:

[0057] This invention proposes a gallium oxide high-power device with high overall heat dissipation performance. Its features include: a chip 12 fabricated from a gallium oxide wafer with reduced substrate thickness achieved through mechanical thinning and polishing to reduce thermal resistance through the substrate region; a double-sided packaging structure and a molding compound 9 with high thermal conductivity to improve heat conduction efficiency; ultimately enhancing the overall heat dissipation performance of the gallium oxide high-power device, resulting in a device with high overall heat dissipation performance.

[0058] The present invention proposes a gallium oxide high-power device with efficient comprehensive heat dissipation performance, comprising, from bottom to top, a base plate 1, a bottom insulating ceramic layer 2, an anode substrate 3, an anode pin insulating terminal 4, a cathode pin insulating terminal 5, a cathode substrate 6, a top insulating ceramic layer 7, a top cover plate 8, a molding compound 9, a frame 10, a cathode solder layer 11, a chip 12, an anode solder layer 13; an anode pin 14, and a cathode pin 15;

[0059] The chip 12 is made of gallium oxide wafer through thinning and polishing;

[0060] The anode substrate 3 is used to connect the electrodes of the chip 12. The anode substrate 3 is fixed to the anode pin 14, and the anode pin 14 is used to connect to the external circuit.

[0061] The cathode substrate 6 is used to connect the electrodes of the chip 12. The cathode substrate 6 is fixed to the cathode pin 15, and the cathode pin 15 is used to connect to the external circuit.

[0062] The anode insulating terminal 4 is fixed together with the anode pin 14 and is fixed to the frame 10 to achieve insulation;

[0063] The cathode insulating terminal 5 is fixed together with the cathode pin 15 and is fixed to the frame 10 to achieve insulation;

[0064] The anode substrate 3 is insulated from the base plate 1 by the bottom insulating ceramic layer 2;

[0065] The cathode substrate 6 is insulated from the top cover plate 8 by the top insulating ceramic layer 7;

[0066] The molding compound 9 occupies the largest volume inside the gallium oxide high-power device, filling and immersing the chip 12 and all the bottom insulating ceramic layers 2, top insulating ceramic layers 7, anode substrate 3, cathode substrate 6, cathode solder layer 11 and anode solder layer 13, and expelling the air inside the device.

[0067] Furthermore, the chip 12 is made by thinning and polishing a gallium oxide wafer to below 100μm; the back metallization layer of the gallium oxide wafer after substrate thinning and polishing is a Ti / Au or Ti / Ag composite metal layer.

[0068] Furthermore, the bottom insulating ceramic layer 2 is made of any one of alumina, aluminum nitride, silicon nitride, or beryllium oxide ceramics; the top insulating ceramic layer 7 is made of any one of alumina, aluminum nitride, silicon nitride, or beryllium oxide ceramics.

[0069] Furthermore, the anode solder layer 13 includes a tin-based solder layer or a sintered silver solder layer; the cathode solder layer 11 includes a tin-based solder layer or a sintered silver solder layer.

[0070] Furthermore, the molding compound 9 is a high thermal conductivity molding compound, wherein the thermal conductivity of the molding compound 9 is ≥4.2W / m·K; wherein the molding compound 9 is flexible after curing.

[0071] like Figure 2 The present invention proposes a method for fabricating a gallium oxide high-power device with efficient comprehensive heat dissipation performance, used to fabricate a gallium oxide high-power device with efficient comprehensive heat dissipation performance as described in any one of the present invention; characterized in that it includes the following:

[0072] Step S1: Select a gallium oxide wafer with a completed front-side structure;

[0073] Step S2: Spin-coat photoresist on the front side of the gallium oxide wafer for protection, and fix the front side of the device to the glass plate with heat release tape or wax;

[0074] Step S3: Use a thinning machine to rapidly mechanically thin the substrate of the gallium oxide wafer to below 100 μm;

[0075] Step S4: Rough polish the substrate surface of the thinned gallium oxide wafer;

[0076] Step S5: Perform fine polishing on the substrate surface of the gallium oxide wafer after rough polishing;

[0077] Step S6: Remove surface contaminants from the front side of the wafer;

[0078] Step S7: Deposit metal on the surface of the gallium oxide substrate using evaporation or sputtering processes to form cathode metal;

[0079] Step S8: Divide the thinned gallium oxide wafer to separate individual gallium oxide chips;

[0080] Step S9: The gallium oxide power chip anode is mounted to a designated position on the anode substrate 3 with its own anode pins via the anode solder layer 13;

[0081] Step S10: The gallium oxide power chip cathode is attached to the designated position of the cathode substrate 6 with its own cathode pins through the cathode solder layer 11;

[0082] Step S11: Inject molding compound 9 into the mold cavity where the chip and other structures have been placed, so that it completely covers the gallium oxide power chip, solder, substrate, and ceramic.

[0083] Step S12: Curing is performed under preset temperature and pressure to form the molding compound 9;

[0084] Step S13: Weld the top cover plate 8.

[0085] Furthermore, the spin coating includes: using a spin coater, first depositing at a speed of 200-800 rpm for 8-12 seconds; then increasing the speed to 500-1500 rpm for 30-90 seconds.

[0086] The thinning speed of the aforementioned thinning machine is 6 μm / min.

[0087] The rough polishing of the thinned substrate surface includes:

[0088] Use either alumina polishing slurry or diamond polishing slurry, and a polyurethane soft polishing pad. The rough polishing speed is 60 rpm.

[0089] Furthermore, the surface stain removal treatment of the device includes: immersing the device in an organic wax remover, a cleaning agent, and deionized water in sequence for ultrasonic cleaning for 3-5 minutes each, and then drying the cleaned device with nitrogen gas.

[0090] The method of depositing metal on the surface of gallium oxide substrate using evaporation or sputtering processes includes depositing a metal layer using one or more sputtering processes such as magnetron sputtering, thermal evaporation, and electron beam evaporation.

[0091] Furthermore, the dicing of the thinned gallium oxide wafer in step S8 includes using any one of the following processes: dicing or laser cutting.

[0092] Furthermore, the molding compound 9 mentioned therein is a molding compound or LMP containing boron nitride / aluminum nitride filler. Fill Any one of them.

[0093] In addition to the above, the present invention also has related embodiments, including the following:

[0094] The working principle of this invention is as follows: By thinning the substrate, the thermal resistance of heat flow through the substrate is reduced, while the structure becomes more compact, reducing the package size. A double-sided packaging structure provides high thermal conductivity paths on both the top and bottom sides of the device, forming an efficient double-sided heat dissipation channel, significantly reducing the junction-to-case thermal resistance and junction temperature. Simultaneously, the use of a high thermal conductivity molding compound improves heat dissipation capacity, and its flexible nature after curing effectively absorbs and buffers thermal stress caused by the mismatch in thermal expansion coefficients between materials. This is particularly suitable for protecting ultra-thin and brittle gallium oxide chips, preventing them from cracking and delaminating under stress. This allows the device package to have lower junction temperature, thermal resistance, and low stress, resulting in a high-performance gallium oxide device.

[0095] like Figure 3 , Figure 4 , Figure 5 The device electrodes are connected to the substrate via solder. The substrate and pins are integrated, with the inner substrate connecting the chip electrodes via a solder layer, and the outer pins used to connect to external circuits. The outer pins include anode and cathode pins. Anode and cathode insulating terminals are connected to the pins and fixed to the frame for insulation. Substrates 3 and 6 are insulated from the base plate 1 and cover plate 8 via insulating ceramics 2 and 7. The molding compound occupies most of the internal volume of the device, filling and immersing the chip and all ceramics, substrates, and solder layers, while expelling air from inside the device.

[0096] Figure 6 This paper presents a comparison of the junction temperature and thermal resistance of a gallium oxide Schottky barrier diode with low junction temperature and low thermal resistance achieved by combining substrate thinning, double-sided packaging structure, and high thermal conductivity molding compound in embodiments of the present invention, with that of a conventional packaging structure. Figure 6 It can be seen that the bottom cooling junction temperature and thermal resistance of the unthinned 650μm device are 176.97℃ and 5.40℃ / W, respectively. The bottom cooling junction temperature and thermal resistance of the device thinned to 60μm are 89.21℃ and 0.94℃ / W, respectively. The bottom cooling junction temperature and thermal resistance of the flip-chip device thinned to 60μm are 79.82℃ and 0.46℃ / W, respectively. The junction temperature and thermal resistance of the device using substrate thinning and double-sided packaging are reduced to 54.51℃ and 0.16℃ / W, respectively, representing reductions of 69% and 97%.

[0097] The above are preferred embodiments of the present invention. Any changes made to the technical solution of the present invention that do not exceed the scope of the technical solution of the present invention shall fall within the protection scope of the present invention.

Claims

1. A gallium oxide high-power device with high efficient comprehensive heat dissipation performance, characterized in that, The chip made of the gallium oxide wafer which is thinned and polished to reduce the thickness of the substrate realizes the reduction of the thermal resistance of the heat passing through the substrate area, the double-sided packaging structure is adopted, and the plastic packaging material with high thermal conductivity is adopted to realize the improvement of the heat conduction efficiency; The gallium oxide large power device with high comprehensive heat dissipation performance comprises, from bottom to top, a bottom plate, a bottom insulating ceramic layer, an anode substrate, an anode pin insulating terminal, a cathode pin insulating terminal, a cathode substrate, a top insulating ceramic layer, a top cover plate, plastic packaging material, a frame, a cathode solder layer, a chip, an anode solder layer, an anode pin and a cathode pin. The chip is made of a gallium oxide wafer which is thinned and polished. The anode substrate is used for connecting the electrode of the chip, the anode substrate is fixed with the anode pin, and the anode pin is used for connecting an external circuit. The cathode substrate is used for connecting the electrode of the chip, the cathode substrate is fixed with the cathode pin, and the cathode pin is used for connecting an external circuit. The anode insulating terminal is fixed with the anode pin together, and is fixed with the frame to realize insulation. The cathode insulating terminal is fixed with the cathode pin together, and is fixed with the frame to realize insulation. The anode substrate is insulated and isolated from the bottom plate through the bottom insulating ceramic layer. The cathode substrate is insulated and isolated from the top cover plate through the top insulating ceramic layer. The plastic packaging material occupies the maximum volume in the gallium oxide large power device, fills and immerses the chip and all the bottom insulating ceramic layer, the top insulating ceramic layer, the anode substrate, the cathode substrate, the cathode solder layer and the anode solder layer, and discharges the air in the device.

2. The gallium oxide high-power device with high efficient comprehensive heat dissipation performance according to claim 1, characterized in that, The chip is made of a gallium oxide wafer which is thinned and polished to less than 100 μm; the back surface metallization layer of the gallium oxide wafer after the substrate is thinned and polished is a composite metal layer of Ti / Au or Ti / Ag.

3. The gallium oxide high-power device with high efficient comprehensive heat dissipation performance according to claim 1, characterized in that, The bottom insulating ceramic layer adopts at least one of alumina, aluminum nitride, silicon nitride and beryllium oxide ceramic; and the top insulating ceramic layer adopts at least one of alumina, aluminum nitride, silicon nitride and beryllium oxide ceramic.

4. The gallium oxide high-power device with high efficient comprehensive heat dissipation performance according to claim 1, characterized in that, The anode solder layer comprises a tin-based solder layer or a sintered silver solder layer; and the cathode solder layer comprises a tin-based solder layer or a sintered silver solder layer.

5. The gallium oxide high-power device with high efficient comprehensive heat dissipation performance according to claim 1, characterized in that, The plastic packaging material is high-thermal-conductivity plastic packaging material, the thermal conductivity of the plastic packaging material is greater than or equal to 4.2 W / m·K, and the plastic packaging material is flexible after curing.

6. A method for manufacturing a gallium oxide high-power device with high comprehensive heat dissipation performance, for manufacturing a gallium oxide high-power device with high comprehensive heat dissipation performance according to any one of claims 1 to 5; characterized in that, The method comprises the following steps: Step S1: selecting a gallium oxide wafer with a completed front structure; Step S2: protecting the front of the gallium oxide wafer by spin coating photoresist, and fixing the device front on a glass plate by using a thermal release tape or wax; Step S3: rapidly mechanically thinning the substrate of the gallium oxide wafer to less than 100 μm by using a thinning machine; Step S4: rough polishing the surface of the thinned gallium oxide wafer substrate; Step S5: fine polishing the surface of the thinned gallium oxide wafer substrate; Step S6: removing surface stains on the front of the wafer; Step S7: depositing metal on the surface of the gallium oxide substrate by evaporation or sputtering process to form a cathode metal; Step S8: separating the thinned gallium oxide wafer to obtain a single gallium oxide chip. Step S9: the gallium oxide power chip anode is attached to the designated position of the anode substrate through the anode solder layer; Step S10: the gallium oxide power chip cathode is attached to the designated position of the cathode substrate through the cathode solder layer; Step S11: the plastic sealing material is injected into the mold cavity where the chip and other structures are placed, so as to completely cover the gallium oxide power chip, the solder, the substrate and the ceramic; Step S12: curing is performed at a preset temperature and pressure to shape the plastic sealing material; Step S13: the top cover plate is welded.

7. The method for fabricating a gallium oxide high-power device with high-efficiency comprehensive heat dissipation performance according to claim 6, characterized in that, The spin coating comprises: using a spin coater, first depositing at a speed of 200-800 rpm, and the spin coating time is 8-12 s; then increasing the speed to 500-1500 rpm, and spin coating for 30-90 s; The thinning speed of the thinning machine is 6 μm / min; The rough polishing of the surface of the thinned substrate comprises: Any one of alumina polishing liquid or diamond polishing liquid is used, a polyurethane soft polishing pad is used, and the rough polishing speed is 60 rpm.

8. The method for making gallium oxide high-power devices with high efficiency and comprehensive heat dissipation performance according to claim 6, It is characterized in that; The device is subjected to a surface stain removal treatment, which comprises: sequentially immersing the device in an organic wax remover, a cleaning agent and deionized water, and ultrasonically cleaning each for 3-5 min, and blowing the cleaned device dry with nitrogen; The metal is deposited on the surface of the gallium oxide substrate by using an evaporation or sputtering process, which comprises: using one or more of the sputtering processes of magnetron sputtering, thermal evaporation and electron beam evaporation to deposit a metal layer.

9. The method of claim 6, wherein the gallium oxide high-power device has high comprehensive heat dissipation performance. The thinned gallium oxide wafer in step S8 is subjected to dicing, which comprises: using any one of the dicing and laser cutting processes.

10. The method of claim 6, wherein the gallium oxide high-power device has high comprehensive heat dissipation performance. wherein the plastic encapsulant is any one of plastic encapsulants with boron nitride / aluminum nitride filler or LMP Fill ​

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