Non-contact plasma polishing device and method for gallium oxide wafer

Abstract

The invention discloses a non-contact plasma polishing device and method for a gallium oxide wafer, and belongs to the technical field of semiconductor processing, and the device mainly comprises a processing module, a plasma excitation module, a vacuum control and tail gas treatment module, a gas supply module and an in-situ monitoring module. High-density plasma is excited through multi-gas combination, chemical reaction is used as a main guide, low-energy ion physical bombardment is used as an auxiliary guide, and gallium oxide wafer surface atomic-scale removal and global roughness Rult are achieved; in the polishing process, non-contact dry polishing is carried out on the surface of the gallium oxide wafer through the synergistic effect of physical bombardment and chemical reaction of high-density plasmas, the problems that microcracks and subsurface damage are likely to be introduced in traditional mechanical polishing are solved, and efficient and uniform polishing of fragile materials is achieved. The device adopts a modular design, supports multi-cavity cluster operation, and can meet large-scale industrialization requirements of gallium oxide power devices and photoelectric devices.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor processing technology, and in particular to a non-contact plasma polishing device and method for gallium oxide wafers. Background Art

[0002] Gallium oxide (Ga2O3), as an ultra-wide bandgap semiconductor material, is widely used in power devices and solar-blind ultraviolet detection. The roughness, flatness and crystal integrity of the substrate surface are crucial to the performance of the device. However, the traditional chemical mechanical polishing (CMP) technology used for silicon-based semiconductors has limitations in its application to highly brittle and easily cleaved materials such as Ga2O3: the mechanical pressure and abrasive particles applied during the CMP process can easily cause damage, scratches and cleavage on the wafer surface. In addition, the CMP process is time-consuming and difficult to further reduce the roughness. These factors limit the processing quality of the Ga2O3 substrate and even the final device performance. Existing research (published in 2016 " Semiconductor Science and Technology ", Volume 31, Issue 6, 065006 (6pp) titled " Chlorine-based dry etching of β-Ga2O3 ", doi:10.1088 / 0268-1242 / 31 / 6 / 065006) utilizes chlorine-based mixed gas to carry out dry etching of Ga2O3 crystal, and has achieved high etching rate and smooth surface. Therefore, the plasma polishing process using chlorine-based mixed gas as main reaction gas has the potential to process Ga2O3 substrate. However, there is currently a lack of equipment and technology specifically for ultra-precision polishing of Ga2O3 crystal, particularly in large-scale (such as 6-inch class) substrate processing and industrial mass production. There is no mature solution. Therefore, there is an urgent need to design a special device and method to achieve high-efficiency, low-damage non-contact plasma polishing of Ga2O3 substrates. Summary of the Invention

[0003] In response to the defects and shortcomings of the above-mentioned prior art, the present invention provides a non-contact plasma polishing device and method for gallium oxide wafers. By exciting plasma with a combination of multiple gases, gallium oxide wafers are polished non-contactly, achieving high-precision, low-damage surface treatment, and solving the problems of traditional mechanical polishing methods such as large material loss, severe thermal damage, and difficult to control surface scratches.

[0004] The technical solutions of the present invention are as follows:

[0005] The present invention provides a non-contact plasma polishing device for gallium oxide wafers, comprising the following modules: a processing module, a plasma excitation module, a vacuum control and tail gas treatment module, a gas supply module and an in-situ monitoring module.

[0006] Furthermore, the processing module is used to process the wafer, including a cavity 101, a gas homogenizing device 102, a wafer carrier 107, an observation window 113, a wafer conveying channel 114, and an exhaust port 115; the cavity 101 includes a cavity wall and a Y2O3 anti-corrosion layer coated on the cavity wall; the gas homogenizing device 102 is fixed to the top of the cavity 101 to ensure uniform plasma distribution during processing; the wafer carrier 107 is located at the bottom of the cavity 101 to fix and support the wafer 112, with an upper and lower range of 0-100m m height adjustment function, and an adjustable rotation speed of 0-20rpm can be achieved during processing; the observation window 113 is located on the left side of the cavity 101, for observing the internal situation of the cavity 101, so that the in-situ monitoring module can collect processing data in real time; the wafer conveying channel 114 is located on the right side of the cavity 101, for connecting other working chambers, supporting multi-cavity cluster configuration and multi-wafer processing; the exhaust port 115 is located at the bottom of the cavity 101, for connecting the vacuum control and exhaust gas treatment modules, to realize the internal air pressure regulation of the cavity 101 and the discharge of by-products.

[0007] Furthermore, the plasma excitation module is used to generate the plasma required for processing, is located above the cavity 101, and includes a plasma excitation chamber 201 and a gas mixing chamber 301; the plasma excitation chamber 201 is used to apply electrical excitation to the uniformly mixed gas to generate high-density plasma; the gas mixing chamber 301 is located directly above the plasma excitation chamber 201, and is used to mix the reaction gas provided by the gas supply module and form a uniform downward airflow, which is then passed into the plasma excitation chamber 201.

[0008] Furthermore, the vacuum control and exhaust gas treatment module is used to adjust the air pressure inside the chamber and treat by-products generated during the processing. It is located below the cavity 101 and includes a vacuum control system 401, an exhaust gas treatment system 402, a bellows 403, a snap 404, a pressure regulating valve 405, a vacuum pressure gauge 406, and an exhaust pipe 407; the vacuum control system 401, the pressure regulating valve 405, and the vacuum pressure gauge 406 are used to adjust the air pressure inside the cavity 101; the exhaust gas treatment system 402 is used to treat by-products generated during the processing; the bellows 403 and the snap 404 are used to connect the vacuum control system 401, the exhaust gas treatment system 402 and the exhaust pipe 407; the exhaust pipe 407 is used to connect the vacuum control system 401 and the cavity 101.

[0009] Furthermore, the gas supply module is used to provide the reaction gas, auxiliary gas and cooling gas required for processing the wafer, including a first reaction gas source 501, a second reaction gas source 502, a carrier gas source 503, an auxiliary gas source 504, a cooling gas source 505, a pressure reducing valve 506, a mass flow controller 507, and a shut-off valve 508; the first reaction gas source 501 and the second reaction gas source 502 are used to provide different reaction gases; the carrier gas source 503 is used to provide a stable atmosphere to support plasma stability; the auxiliary gas source 504 is used to provide auxiliary gas to improve the polishing effect; the cooling gas source 505 is used to provide cooling gas to maintain the wafer at a constant temperature during the processing; the pressure reducing valve 506, the mass flow controller 507, and the shut-off valve 508 are used to control the entry of the gas source and adjust the gas flow.

[0010] Furthermore, the in-situ monitoring module is used to monitor the changes in plasma components during the processing process in real time. It is located on the side of the observation window 113 of the cavity 101 and includes a spectrometer 601, an optical probe 602, and an optical fiber 603; the spectrometer 601 is used to analyze the plasma components during the processing process; the optical probe 602 and the optical fiber 603 are used to collect processing data in real time and transmit it to the spectrometer 601.

[0011] Furthermore, the wafer carrying device 107 includes an electrostatic chuck 108, a focusing ring 109, an insulating ring 110, and a radio frequency power supply A 111; the electrostatic chuck 108 is used to adsorb and fix the wafer 112 to be processed, and is passed through cooling water and cooling gas to ensure that the wafer 112 is at a stable temperature; the focusing ring 109 and the insulating ring 110 are used to ensure that the plasma acts evenly on the surface of the wafer 112, and the focusing ring 109 is made of one of silicon carbide or boron carbide; the radio frequency power supply A 111 is used to provide a stable bias voltage to the electrostatic chuck 108.

[0012] Furthermore, the gas homogenizing device 102 includes a first gas homogenizing chamber 103, a first gas homogenizing plate 104, a second gas homogenizing chamber 105, and a second gas homogenizing plate 106. The first and second gas homogenizing chambers 103 and 105 are used to distribute the incoming gas, while the first and second gas homogenizing plates 104 and 106 are used to evenly distribute the gas, ensuring that the plasma has a uniform effect on the wafer surface. The first and second gas homogenizing plates 104 and 106 are provided with through holes with a diameter of 0.05-1mm. The through hole density is arranged in a gradient distribution, with a through hole density of 5% in the center area and up to 30% in the edge area, to achieve edge compensation and optimize plasma uniformity.

[0013] Furthermore, the plasma excitation chamber 201 includes a quartz tube 202, an induction coil 203, a matcher 204, and a radio frequency power supply B 205. The quartz tube 202 is used to contain gas and excite plasma through inductive coupling. The induction coil 203 is made of a copper tube and has cooling water flowing through it to provide a stable high-frequency electric field. The matcher 204 is used to match the power of the radio frequency power supply B 205 with that of the induction coil. The radio frequency power supply B 205 is used to provide a stable bias voltage, has an operating frequency of 13.56 MHz, and a continuously adjustable output power of 50-1500 W.

[0014] Furthermore, the mixing chamber 301 includes a third uniform gas chamber 302, a third uniform gas plate 303, a fourth uniform gas chamber 304, a fourth uniform gas plate 305, a fifth uniform gas chamber 306, and a fifth uniform gas plate 307; the third uniform gas chamber 302, the fourth uniform gas chamber 304, and the fifth uniform gas chamber 306 are respectively introduced into the first reaction gas in the first reaction gas source 501, the second reaction gas in the second reaction gas source 502, and the carrier gas in the carrier gas source 503, and the distribution and mixing of different gases are realized through the third uniform gas plate 303, the fourth uniform gas plate 305, and the fifth uniform gas plate 307, to ensure that the mixed airflow is uniformly downward, and then introduced into the plasma excitation chamber 201.

[0015] Furthermore, the gases in the first reaction gas source 501 , the second reaction gas source 502 , the carrier gas source 503 , the auxiliary gas source 504 , and the cooling gas source 505 are preferably Cl 2 , BCl 3 , Ar, O 2 , and He, respectively.

[0016] The present invention also provides a non-contact plasma polishing method for gallium oxide wafers, comprising the following steps:

[0017] Step 1: The wafer 112 is delivered into the chamber 101 through the wafer transfer channel 114 and placed on the wafer carrier 107 ; the vacuum control system 401 is turned on to evacuate the chamber 101 to a background pressure of ≤1 Pa;

[0018] Step 2: Introduce the carrier gas from the carrier gas source 503 and the auxiliary gas from the auxiliary gas source 504 into the gas mixing chamber 301 at a gas flow ratio of carrier gas (10-40 sccm): auxiliary gas (0-20 sccm), adjust the RF power of the RF power supply B 205 to 50-200 W to excite the plasma; introduce the carrier gas from the carrier gas source 503 into the cavity 101, adjust the pressure of the cavity 101 to 5-20 Pa, and pre-treat the surface of the wafer 112 for 0-20 minutes;

[0019] Step 3: The first reaction gas from the first reaction gas source 501 and the second reaction gas from the second reaction gas source 502 are introduced into the gas mixing chamber 301 while reducing the flow rate of the auxiliary gas. The gas flow rate ratio is maintained at first reaction gas (10-30 sccm): second reaction gas (2-10 sccm): carrier gas (10-40 sccm): auxiliary gas (0-10 sccm). The RF power of RF power source B 205 is adjusted to 150 W-1500 W to obtain a stable plasma for polishing the surface of the wafer 112.

[0020] Step 4: During polishing, a bias voltage of 500-800V is applied to the electrostatic chuck 108 to hold the wafer 112. Simultaneously, cooling gas (gas flow rate 5-10 sccm) from the cooling gas source 505 is introduced for backside cooling. The rotation speed of the wafer 112 can be set to 0-20 rpm to improve uniformity. The temperature of the wafer 112 is controlled within the range of 25-100°C to ensure process stability and prevent thermal stress damage.

[0021] Step 5: Using the in-situ monitoring module, the optical probe 602 and the spectrometer 601 on one side of the observation window 113 are used to monitor the plasma components in real time and provide feedback to control the processing parameters.

[0022] Step 6: After polishing is completed, stop introducing the first reaction gas and the second reaction gas into the gas mixing chamber 301, continue to maintain the introduction of the carrier gas and the auxiliary gas, readjust the gas flow ratio of the carrier gas (10-40 sccm): the auxiliary gas (0-20 sccm) and the RF power of the RF power supply B 205 to 50-200W, and re-treat the surface of the wafer 112 to remove residual reactants and by-products. The processing time is 0-20 minutes.

[0023] Step 7: After the processing is completed, the polished wafer 112 is sent out of the cavity 101 through the wafer transfer channel 114, and the next wafer to be processed is introduced to support continuous multi-wafer processing.

[0024] Beneficial effects of the present invention:

[0025] The present invention provides a non-contact plasma polishing device and method for gallium oxide wafers. By exciting high-density plasma through a combination of multiple gases, with chemical reactions as the main method and supplemented by low-energy ion physical bombardment, atomic-level removal of the surface of the gallium oxide wafer is achieved, with a global roughness of Ra < 0.5nm, avoiding the problems of sub-surface microcracks and surface scratches in traditional mechanical polishing. The gas ratio is accurately adjusted by in-situ monitoring and real-time feedback of processing data, thereby improving the polishing efficiency of gallium oxide wafers. By controlling the wafer temperature, thermal stress generated during processing is avoided, greatly reducing thermal damage. At the same time, the device adopts a modular design, supports continuous multi-wafer processing and multi-cavity cluster operation, and can meet the large-scale industrialization needs of gallium oxide power devices and optoelectronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings illustrate various embodiments generally by way of example and not limitation, and together with the description and claims, serve to explain embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive of the embodiments of the present apparatus or method.

[0027] Figure 1 The figure is a schematic diagram of the overall structure of a non-contact plasma polishing device for gallium oxide wafers according to the present invention.

[0028] Figure 2 This is a schematic structural diagram of a processing module and an in-situ monitoring module of a non-contact plasma polishing device for gallium oxide wafers of the present invention.

[0029] Figure 3 This is a schematic structural diagram of a plasma excitation module of a non-contact plasma polishing device for gallium oxide wafers of the present invention.

[0030] Figure 4 This is a schematic structural diagram of the vacuum control and tail gas treatment modules of a non-contact plasma polishing device for gallium oxide wafers of the present invention.

[0031] Figure 5 The present invention is a schematic diagram of the structure of a gas supply module of a non-contact plasma polishing device for gallium oxide wafers.

[0032] Explanation of the reference numerals: 101-reaction chamber, 102-substrate carrying mechanism, 103-first uniform gas chamber, 104-first uniform gas plate, 105-second uniform gas chamber, 106-second uniform gas plate, 107-wafer carrying device, 108-electrostatic chuck, 109-focusing ring, 110-insulating ring, 111-RF power supply A, 112-wafer, 113-observation window, 114-wafer transmission channel, 115-exhaust port, 201-plasma excitation chamber, 202-quartz tube, 203-induction coil, 204-matching device, 205-RF power supply B, 301-gas mixing chamber, 302-third uniform gas chamber, 303-third uniform gas plate, 304-fourth uniform gas chamber, 305-fourth uniform gas Plate, 306-fifth uniform gas chamber, 307-fourth uniform gas plate, 401-vacuum control system, 402-exhaust gas treatment system, 403-bellows, 404-clamp, 405-pressure regulating valve, 406-vacuum pressure gauge, 407-exhaust pipeline, 501-first reaction gas supply source, 502-second reaction gas supply source, 503-carrier gas source, 504-auxiliary gas source, 505-cooling gas source, 506-pressure reducing valve, 507-mass flow controller, 508-stop valve, 509-first reaction gas pipeline, 510-second reaction gas pipeline, 511-first mixed gas pipeline, 512-second mixed gas pipeline, 601-spectrometer, 602-optical probe, 603-optical fiber. DETAILED DESCRIPTION

[0033] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0034] The embodiment of the present invention provides a non-contact plasma polishing device for gallium oxide wafers, such as Figure 1 As shown, it includes the following modules: a processing module, a plasma excitation module, a vacuum control and exhaust gas treatment module, a gas supply module and an in-situ monitoring module.

[0035] The processing module is used to process the wafer 112. In this embodiment, the wafer 112 is a gallium oxide wafer. Figure 2As shown, it includes a cavity 101, a gas homogenizing device 102, a wafer carrier 107, an observation window 113, a wafer conveying channel 114 and an exhaust port 115. The cavity 101 includes a cavity wall made of stainless steel and a Y2O3 anti-corrosion layer coated on the inner wall of the cavity. The gas homogenizing device 102 is fixed to the top of the cavity 101 to ensure that the plasma is evenly distributed during the processing. The plasma introduced by the plasma excitation chamber 201 enters the first gas homogenizing chamber 103 and the second gas homogenizing chamber 105 respectively and is evenly distributed through the first gas homogenizing plate 104 and the second gas homogenizing plate 106 to ensure that the plasma acts evenly on the wafer surface. The first gas homogenizing plate 104 and the second gas homogenizing plate 106 are provided with through holes, the through hole diameter is 0.05-1mm, and the through hole density is arranged in a gradient distribution. The through hole density in the central area is 5%, and the edge area can reach up to 30% to achieve edge compensation and optimize plasma uniformity. Wafer support device 107 is located at the bottom of chamber 101 and includes an electrostatic chuck 108, a focusing ring 109, an insulating ring 110, and a radio frequency power supply A 111. Electrostatic chuck 108 is used to hold wafer 112 to be processed. Cooling water and cooling gas from a cooling gas source 505 are supplied to maintain a stable temperature for wafer 112. Focusing ring 109 and insulating ring 110 ensure uniform plasma application to the surface of wafer 112. Focusing ring 109 is made of silicon carbide. Radio frequency power supply A 111 provides a stable bias voltage to electrostatic chuck 108. Wafer support device 107 is adjustable in height (0-100 mm) and rotates at a constant speed (0-20 rpm) during processing.

[0036] An exhaust port 115 is also provided at the bottom of the cavity 101 for connecting the vacuum control and exhaust gas treatment modules. An observation window 113 is provided on the left side of the cavity 101 for observing the internal situation of the chamber, so that the in-situ monitoring module can collect processing data in real time and monitor the changes in plasma components during the processing. The in-situ monitoring module includes a spectrometer 601, an optical probe 602, and an optical fiber 603; the optical probe 602 and the optical fiber 603 are used to collect processing data in real time and transmit it to the spectrometer 601, and the spectrometer 601 is used to analyze the plasma components during the processing. The wafer conveying channel 114 is provided on the right side of the cavity 101 for connecting to other working chambers to support multi-cavity cluster configuration and multi-wafer continuous processing.

[0037] The plasma excitation module is used to generate the plasma required for processing, such as Figure 3As shown, the gas mixing chamber 301 is located above the chamber 101 and includes a plasma excitation chamber 201 and a gas mixing chamber 301. The gas mixing chamber 301 is located directly above the plasma excitation chamber 201 and includes a third gas homogenizing chamber 302, a third gas homogenizing plate 303, a fourth gas homogenizing chamber 304, a fourth gas homogenizing plate 305, a fifth gas homogenizing chamber 306, and a fifth gas homogenizing plate 307. The third gas homogenizing chamber 302, the fourth gas homogenizing chamber 304, and the fifth gas homogenizing chamber 306 are respectively fed with the first reaction gas from the first reaction gas source 501, the second reaction gas from the second reaction gas source 502, and the carrier gas from the carrier gas source 503. The first reaction gas, the second reaction gas, and the carrier gas provided by the gas supply module are mixed through the third gas homogenizing plate 303, the fourth gas homogenizing plate 305, and the fifth gas homogenizing plate 307 to form a uniform downward airflow that enters the quartz tube 202. The plasma excitation chamber 201 includes a quartz tube 202, an induction coil 203, a matching device 204, and an RF power supply B 205. The gas uniformly mixed in the gas mixing chamber 301 enters the quartz tube 202, is electrically excited by the induction coil 203, and generates a high-density plasma. The plasma is then fed into the gas homogenization device 102 within the cavity 101.

[0038] The vacuum control and tail gas treatment module is used to adjust the air pressure inside the chamber 101 and to treat by-products generated during the processing, such as Figure 4 As shown, the vacuum control system 401 is located below the chamber 101 and includes a vacuum control system 401, an exhaust gas treatment system 402, a bellows 403, a buckle 404, a pressure regulating valve 405, a vacuum pressure gauge 406, and an exhaust pipe 407. The vacuum control system 401, the exhaust gas treatment system 402, and the exhaust pipe 407 are connected using the bellows 403 and the buckle 404. The vacuum control system 401 regulates the air pressure inside the chamber through the pressure regulating valve 405 and the vacuum pressure gauge 406 via the exhaust pipe 407.

[0039] The gas supply module is used to provide the reaction gas, auxiliary gas and cooling gas required for wafer processing, such as Figure 5As shown, the system includes a first reaction gas source 501, a second reaction gas source 502, a carrier gas source 503, an auxiliary gas source 504, a cooling gas source 505, a pressure reducing valve 506, a mass flow controller 507, a shut-off valve 508, a first reaction gas pipeline 509, a second reaction gas pipeline 510, a first mixed gas pipeline 511, a second mixed gas pipeline 512, and a cooling gas pipeline 513. The first reaction gas source 501 and the second reaction gas source 502 are used to provide reaction gases, and in this embodiment, Cl2 and BCl3 are respectively selected. The carrier gas source 503 is used to provide carrier gas, and Ar is selected to support plasma stability. The auxiliary gas source 504 is used to provide auxiliary gas, and O2 is selected to improve the polishing effect. The cooling gas source 505 is used to provide cooling gas, and He is selected to maintain a constant temperature of the wafer 112 during processing. The gas supply module controls the entry and flow rate of each gas source through the pressure reducing valve 506, the mass flow controller 507 and the shut-off valve 508, and provides corresponding gases to the gas homogenizing device 102, the wafer carrier device 107 and the gas mixing chamber 301 through each gas pipeline.

[0040] This embodiment also provides a non-contact plasma polishing method for gallium oxide wafers, comprising the following steps:

[0041] Step 1: A 2-inch (100) gallium oxide wafer is delivered into the processing chamber through the wafer transfer channel 114 and placed on the wafer carrier 107; the vacuum control system 401 is turned on and the interior of the chamber 101 is evacuated to below 0.5 Pa.

[0042] Step 2: Ar and O2 are introduced into the mixed gas chamber 301 with a gas flow ratio of Ar (20 sccm): O2 (10 sccm), and the RF power of the RF power supply A205 is adjusted to 150 W to excite the plasma; Ar is introduced into the cavity 101, and the pressure of the cavity 101 is adjusted to 5 Pa to pre-treat the surface of the gallium oxide wafer for 10 minutes.

[0043] Step 3: Introduce the main etching gases Cl2 and BCl3 into the mixed gas chamber 301 while reducing the O2 flow rate; maintain the gas flow ratio of Cl2 (15 sccm): BCl3 (5 sccm): Ar (20 sccm): O2 (2 sccm); adjust the RF power of the RF power supply A205 to 800 W to obtain a stable plasma for polishing the surface of the gallium oxide wafer.

[0044] Step 4: During the polishing process, a bias voltage of 500 V is applied to the electrostatic chuck 108 to adsorb the gallium oxide wafer, and He (gas flow rate 5 sccm) is introduced for back side cooling; the wafer rotation speed can be set to 5 rpm to improve uniformity, and the wafer temperature is controlled at 30°C.

[0045] Step 5: Using the in-situ monitoring module, the plasma components are monitored in real time through the optical probe 602 and the spectrometer 601 on one side of the observation window 113, and the processing parameters are feedback-controlled.

[0046] Step 6: After polishing is completed, stop introducing Cl2 and BCl3 into the gas mixing chamber 301, continue to maintain the introduction of Ar and O2, readjust the gas flow ratio Ar (20 sccm): O2 (10 sccm) and the RF power of the RF power supply A205 to 150 W, and re-treat the surface of the gallium oxide wafer to remove residual reactants and by-products. The processing time is 20 minutes.

[0047] Step 7: After the processing is completed, the polished gallium oxide wafer is sent out of the processing chamber 101 through the wafer transfer channel 114, and the next wafer to be processed is introduced to support continuous multi-wafer processing.

[0048] The above is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A non-contact plasma polishing device for gallium oxide wafers, characterized in that: It includes the following modules: processing module, plasma excitation module, vacuum control and exhaust gas treatment module, gas supply module and in-situ monitoring module; The processing module is used for processing wafers, and comprises a cavity (101), a gas homogenizing device (102), a wafer carrier (107), an observation window (113), a wafer conveying channel (114), and an exhaust port (115); the cavity (101) comprises a cavity wall and a Y2O3 anti-corrosion layer coated on the cavity wall; the gas homogenizing device (102) is fixed to the top of the cavity (101) to ensure uniform plasma distribution during processing; the wafer carrier (107) is located in the cavity The bottom of the body (101) is used to fix and support the wafer (112), and has an adjustment function of 0-100mm in height, and can achieve an adjustable rotation speed of 0-20rpm during processing; the observation window (113) is located on the left side of the cavity (101) and is used to observe the internal situation of the cavity (101), so that the in-situ monitoring module can collect processing data in real time; the wafer conveying channel (114) is located on the right side of the cavity (101) and is used to connect other working chambers to support multi-cavity cluster configuration and multi-wafer processing; The exhaust port (115) is located at the bottom of the cavity (101) and is used to connect the vacuum control and tail gas treatment modules to achieve air pressure regulation inside the cavity and discharge of by-products.

2. The non-contact plasma polishing device for gallium oxide wafers according to claim 1, characterized in that: The plasma excitation module is used to generate plasma required for processing, is located above the cavity (101), and includes a plasma excitation chamber (201) and a gas mixing chamber (301); the plasma excitation chamber (201) is used to apply electrical excitation to the uniformly mixed gas to generate high-density plasma; the gas mixing chamber (301) is located directly above the plasma excitation chamber (201), and is used to mix the reaction gas provided by the gas supply module and form a uniform downward airflow, which is then introduced into the plasma excitation chamber (201).

3. The non-contact plasma polishing device for gallium oxide wafers according to claim 1, characterized in that: The vacuum control and tail gas treatment module is used to adjust the air pressure inside the chamber and treat by-products generated during the processing. It is located below the chamber (101) and includes a vacuum control system (401), a tail gas treatment system (402), a bellows (403), a buckle (404), a pressure regulating valve (405), a vacuum pressure gauge (406), and an exhaust pipeline (407); the vacuum control system (401), the pressure regulating valve (405), and the vacuum pressure gauge (406) are used to adjust the air pressure inside the chamber (101); the tail gas treatment system (402) is used to treat by-products generated during the processing; the bellows (403) and the buckle (404) are used to connect the vacuum control system (401), the tail gas treatment system (402), and the exhaust pipeline (407); and the exhaust pipeline (407) is used to connect the vacuum control system (401) and the chamber (101).

4. The non-contact plasma polishing device for gallium oxide wafers according to claim 1, characterized in that: The gas supply module is used to provide the reaction gas, auxiliary gas and cooling gas required for processing the wafer, and includes a first reaction gas source (501), a second reaction gas source (502), a carrier gas source (503), an auxiliary gas source (504), a cooling gas source (505), a pressure reducing valve (506), a mass flow controller (507) and a stop valve (508); the first reaction gas source (501) and the second reaction gas source (502) are used to provide different reaction gases; the carrier gas source (503) is used to provide a stable atmosphere to support plasma stability; the auxiliary gas source (504) is used to provide auxiliary gas to improve the polishing effect; the cooling gas source (505) is used to provide cooling gas to maintain the wafer at a constant temperature during the processing; the pressure reducing valve (506), the mass flow controller (507) and the stop valve (508) are used to control the introduction of the gas source and adjust the gas flow; The in-situ monitoring module is used to monitor the changes in plasma components during the processing in real time, is located on one side of the observation window (113) of the cavity (101), and includes a spectrometer (601), an optical probe (602), and an optical fiber (603); the spectrometer (601) is used to analyze the plasma components during the processing; the optical probe (602) and the optical fiber (603) are used to collect processing data in real time and transmit it to the spectrometer (601).

5. The non-contact plasma polishing device for gallium oxide wafers according to claim 1, characterized in that: The wafer carrying device (107) comprises an electrostatic chuck (108), a focusing ring (109), an insulating ring (110), and a radio frequency power supply A (111); the electrostatic chuck (108) is used to adsorb and fix a wafer (112) to be processed, and is passed through cooling water and cooling gas to ensure that the wafer (112) is at a stable temperature; the focusing ring (109) and the insulating ring (110) are used to ensure that plasma acts evenly on the surface of the wafer (112), and the focusing ring (109) is made of one of silicon carbide and boron carbide; the radio frequency power supply A (111) is used to provide a stable bias voltage to the electrostatic chuck (108).

6. The non-contact plasma polishing device for gallium oxide wafers according to claim 1, characterized in that: The gas homogenizing device (102) comprises a first gas homogenizing chamber (103), a first gas homogenizing plate (104), a second gas homogenizing chamber (105), and a second gas homogenizing plate (106); the first gas homogenizing chamber (103) and the second gas homogenizing chamber (105) are used to distribute the gas introduced; the first gas homogenizing plate (104) and the second gas homogenizing plate (106) are used to evenly distribute the gas to ensure that the plasma has a uniform effect on the wafer surface; the first gas homogenizing plate (104) and the second gas homogenizing plate (106) are provided with through holes, the through hole diameters are 0.05-1 mm, and the through hole density is arranged in a gradient distribution, the through hole density in the central area is 5%, and the through hole density in the edge area can reach up to 30%, so as to achieve edge compensation and optimize plasma uniformity.

7. The non-contact plasma polishing device for gallium oxide wafers according to claim 2, characterized in that: The plasma excitation chamber (201) comprises a quartz tube (202), an induction coil (203), a matcher (204), and a radio frequency power supply B (205); the quartz tube (202) is used to contain gas and excite plasma through inductive coupling; the induction coil (203) is made of a copper tube and is passed through cooling water to provide a stable high-frequency electric field; the matcher (204) is used to match the power of the radio frequency power supply B (205) and the induction coil; the radio frequency power supply B (205) is used to provide a stable bias voltage, has an operating frequency of 13.56 MHz, and a continuously adjustable output power of 50-1500 W.

8. The non-contact plasma polishing device for gallium oxide wafers according to claim 3, characterized in that: The gas mixing chamber (301) includes a third gas homogenizing chamber (302), a third gas homogenizing plate (303), a fourth gas homogenizing chamber (304), a fourth gas homogenizing plate (305), a fifth gas homogenizing chamber (306), and a fifth gas homogenizing plate (307); the first reaction gas in the first reaction gas source (501), the second reaction gas in the second reaction gas source (502), and the carrier gas in the carrier gas source (503) are respectively introduced into the third gas homogenizing chamber (302), the fourth gas homogenizing plate (304), and the fifth gas homogenizing chamber (306), and the distribution and mixing of different gases are achieved through the third gas homogenizing plate (303), the fourth gas homogenizing plate (305), and the fifth gas homogenizing plate (307), so as to ensure that the mixed gas flow is uniformly downward.

9. The non-contact plasma polishing device for gallium oxide wafers according to claim 5, characterized in that: The gases in the first reaction gas source (501), the second reaction gas source (502), the carrier gas source (503), the auxiliary gas source (504), and the cooling gas source (505) are preferably Cl2, BCl3, Ar, O2, and He, respectively.

10. A non-contact plasma polishing method for gallium oxide wafers, characterized in that: The following steps are involved: Step 1: The wafer (112) is delivered into the cavity (101) through the wafer transfer channel (114) and placed on the wafer carrier (107); the vacuum control system (401) is turned on and the cavity (101) is evacuated to a background pressure of ≤1 Pa; Step 2: introducing the carrier gas in the carrier gas source (503) and the auxiliary gas in the auxiliary gas source (504) into the gas mixing chamber (301), with the gas flow ratio being carrier gas (10-40 sccm): auxiliary gas (0-20 sccm), and adjusting the radio frequency power of the radio frequency power supply B (205) to 50-200 W to excite plasma; introducing the carrier gas in the carrier gas source (503) into the cavity (101), adjusting the pressure of the cavity (101) to 5-20 Pa, and pre-treating the surface of the wafer (112) for a treatment time of 0-20 min; Step 3: introducing the first reaction gas in the first reaction gas source (501) and the second reaction gas in the second reaction gas source (502) into the gas mixing chamber (301), while reducing the flow rate of the auxiliary gas; maintaining the gas flow ratio of the first reaction gas (10-30 sccm): the second reaction gas (2-10 sccm): the carrier gas (10-40 sccm): the auxiliary gas (0-10 sccm); adjusting the radio frequency power of the radio frequency power supply B (205) to 150W-1500W to obtain a stable plasma for polishing the surface of the wafer (112); Step 4: During the polishing process, a bias voltage of 500-800V is applied to the electrostatic chuck (108) to adsorb the wafer (112), and cooling gas (gas flow rate 5-10 sccm) from the cooling gas source (505) is introduced for back cooling; the rotation speed of the wafer (112) is set to 0-20 rpm to improve uniformity, and the temperature of the wafer (112) is controlled within the range of 25-100°C to ensure processing stability and prevent thermal stress damage; Step 5: Using an in-situ monitoring module, the plasma components are monitored in real time through an optical probe (602) and a spectrometer (601) on one side of the observation window (113), and processing parameters are controlled by feedback; Step 6: After polishing is completed, stop introducing the first reaction gas and the second reaction gas into the gas mixing chamber (301), continue to maintain the introduction of the carrier gas and the auxiliary gas, readjust the gas flow ratio of the carrier gas (10-40 sccm): the auxiliary gas (0-20 sccm) and the radio frequency power of the radio frequency power supply B (205) to 50-200W, and re-treat the surface of the wafer (112) to remove residual reactants and by-products, and the treatment time is 0-20 minutes; Step 7: After the processing is completed, the polished wafer (112) is sent out of the cavity (101) through the wafer transfer channel (114), and the next wafer to be processed is introduced to support continuous multi-wafer processing.

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