Photoelectrochemical mechanical polishing device and method based on quartz column light guide

Abstract

The invention discloses a photoelectrochemical mechanical polishing device and method based on quartz column light guide. The device comprises a machine tool base body unit, a workpiece unit, a polishing disc unit, a liquid supply unit, a finishing unit and a laser measuring head. The polishing disc unit is driven by the hollow rotary table, and large-range adjustment of irradiation light intensity is achieved by installing the LED lamp beads with different emergent angles such as 30 degrees, 45 degrees or 60 degrees. A light source of the LED lamp bead is reflected by the hole wall of the stainless steel with the hole and refracted by the quartz column and then irradiates the surface of the wafer, generation of electron hole pairs on the surface of the wafer is promoted, an electric field is applied in cooperation with electricity output from the center of the conductive film, efficient oxidation of the surface of the wafer is achieved, and the material removal rate is increased; the workpiece unit adsorbs a wafer through the conductive vacuum chuck, meanwhile, the trimming unit and the laser measuring head are combined, online trimming and surface type detection of the polishing pad are achieved, and the intelligent level of the polishing process is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision machining technology, and in particular to an opto-chemical mechanical polishing device and method based on quartz column light guide. Background Technology

[0002] As the semiconductor industry upgrades towards high-frequency, high-voltage, and high-temperature applications, wide-bandgap semiconductors (such as silicon carbide (SiC) and gallium nitride (GaN)) have become core materials in fields such as new energy vehicles, photovoltaic inverters, and aerospace due to their superior characteristics, including high breakdown voltage, high thermal conductivity, and low switching losses. However, the strong covalent bonding energy and high hardness of wide-bandgap semiconductor crystals pose bottlenecks for traditional mechanical polishing techniques, such as low processing efficiency, numerous surface defects, and thick subsurface damage layers. These limitations make it difficult to meet the stringent requirements of device manufacturing for wafers, which demand "atomic-level flatness, low defect density, and high surface finish."

[0003] Against this backdrop, photoelectrochemical mechanical polishing (PECMP) technology has emerged. This technology integrates the synergistic effects of multiple energy fields: light excitation to generate electron-hole pairs on the semiconductor surface accelerates the surface oxidation reaction, forming an easily removable oxide layer. Electrochemical enhancement of oxidation kinetics is then combined with mechanical polishing to achieve efficient and low-damage removal of the oxide layer. Compared to traditional mechanical polishing, PECMP technology can significantly reduce processing stress and surface defects. However, existing PECMP technologies still have limitations in practical applications, such as: poor light field uniformity, insufficient synergy of oxidation reactions, and insufficient local light intensity leading to low electron-hole pair generation efficiency and slow oxide layer growth; excessive light intensity may cause over-oxidation, forming an uneven, thick oxide layer, increasing the difficulty of mechanical polishing; insufficient light transmittance and stability make it difficult to achieve uniform illumination on large-area wafers. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an opto-chemical mechanical polishing device and method based on quartz pillar light guide, which can improve the light field intensity and uniformity, excite the generation of electron-hole pairs on the semiconductor surface, generate an easily removable oxide layer, and effectively improve processing efficiency and processing quality.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A photoelectrochemical mechanical polishing device based on quartz column light guide includes a machine tool base unit, a workpiece unit, a polishing disc unit, a liquid supply unit, a dressing unit, and a laser probe. The machine tool base unit is a rectangular frame structure. The workpiece unit is installed on the upper left side of the machine tool base unit. The polishing disc unit is installed on the upper right side of the machine tool base unit. The liquid supply unit is installed on the machine tool base unit and located outside the polishing disc unit. The dressing unit is installed on the machine tool base unit and located outside the polishing disc unit. The laser probe is installed on the dressing unit and located above the polishing disc unit. The polishing disc unit, the workpiece unit, and the polishing fluid form a photoelectrolysis cell.

[0006] Furthermore, the workpiece unit includes a horizontal guide rail, a horizontal moving table, a vertical guide rail, a workpiece moving platform, a cylinder, a workpiece drive motor, a conductive slip ring, a workpiece connecting rod, a coupling, a universal adjustment platform, and a conductive vacuum chuck. The horizontal guide rail is installed on the left side of the worktable, and the worktable is installed on the machine tool base unit. The horizontal moving table is slidably connected to the horizontal guide rail, the vertical guide rail is installed inside the horizontal moving table, and the workpiece moving platform is slidably connected to the vertical guide rail. The cylinder body is installed on the horizontal moving table, and the piston rod end of the cylinder is connected to the workpiece moving platform to drive the workpiece moving platform to rise and fall. The workpiece drive motor is fixed on the workpiece moving platform and is connected to the universal adjustment platform through a coupling and a workpiece connecting rod. The conductive vacuum chuck is installed on the universal adjustment platform, and the lower side of the conductive vacuum chuck adsorbs the wafer. The conductive slip ring passes through the workpiece connecting rod and is fixed to the lower side of the workpiece moving platform.

[0007] Furthermore, the polishing disc unit includes a hollow turntable, a reducer, a spindle motor, an electro-hydraulic slip ring, a stainless steel tray, a rotating shaft, a water-cooled tray, a perforated stainless steel disc, ultraviolet lamp beads, quartz columns, a polishing pad, a conductive film, and a conductive stainless steel sheet. The base of the hollow turntable is installed in the worktable. The power side of the hollow turntable is connected to the spindle motor via the reducer, and the load side of the hollow turntable is connected to the stainless steel tray via the rotating shaft. The stainless steel tray contains a water-cooled tray, and a perforated stainless steel disc is installed on the upper part of the stainless steel tray. The perforated stainless steel disc has lamp holes arranged in an array or radial pattern. Ultraviolet lamp beads are installed in the lamp holes, and quartz columns are embedded above the ultraviolet lamp beads for light guiding. The upper part of the perforated stainless steel disc is sequentially installed from bottom to top with a conductive film, a conductive stainless steel sheet, and a polishing pad. The electro-hydraulic slip ring is installed on the lower part of the rotating shaft.

[0008] Furthermore, the laser probe monitors the surface shape of the polishing pad in real time; the trimming unit is used to trim the surface shape of the polishing pad.

[0009] Furthermore, the conductive stainless steel sheet is connected to an electro-hydraulic slip ring for conductivity, and the wafer is connected to the conductive slip ring via a conductive vacuum chuck to apply an electric field; Furthermore, the emission angle of the ultraviolet light bulb is 30°, 45° or 60°.

[0010] A photoelectrochemical mechanical polishing method based on quartz pillar light guiding, comprising the following steps, using the aforementioned photoelectrochemical mechanical polishing device based on quartz pillar light guiding: S1: The wafer is adsorbed onto the universal adjustment platform of the workpiece unit by a conductive vacuum chuck. Polishing liquid is added by the liquid supply unit so that the polishing liquid wets the surface of the wafer and the surface of the polishing pad, thus completing the polishing pretreatment. S2: The workpiece unit is moved by the horizontal and vertical guide rails to bring the wafer close to the surface of the polishing pad, so that the polishing pad unit, the workpiece unit and the polishing liquid form a photoelectrolysis cell. S3: Start the workpiece drive motor and spindle motor, the wafer and polishing pad begin to rotate, and control the cylinder to make the wafer contact the surface of the polishing pad. S4: Controlling the irradiation intensity and electric field parameters of ultraviolet light allows the wafer surface to undergo controllable oxidation modification under the photoelectrochemical reaction of the photoelectrolysis cell, forming an easily removable oxide layer; at the same time, the relative rotational motion between the polishing disk unit and the wafer is used to remove the oxide layer of the wafer layer layer by layer through mechanical grinding, thereby achieving ultra-smooth planarization of the wafer surface.

[0011] S5: The laser probe monitors the surface shape of the polishing pad in real time and works with the dressing unit to dress the polishing pad to meet processing requirements.

[0012] The working principle of this invention is as follows: pressure is applied by driving the workpiece unit with a cylinder, the relative motion trajectory between the wafer and the polishing pad is made complex by horizontal movement, the wafer is driven to rotate by the workpiece drive motor, the polishing disk is driven to rotate by the spindle motor and the hollow turntable, a light field is applied by ultraviolet light beads, and an electric field is applied by the transparent conductive film and the conductive stainless steel sheet.

[0013] The wafer is connected to the positive terminal of the power supply via a conductive slip ring and a conductive vacuum chuck. A transparent conductive film is attached to the top of the polishing disk, and a conductive stainless steel sheet placed in the middle is connected to the negative terminal of the power supply. The conductive film is conductive on one side, which serves to insulate it from the stainless steel disk below. It can also form an electric field through the polishing liquid on the upper surface and the wafer, which, together with the chemical action, oxidizes the wafer surface. Finally, the wafer surface is polished by mechanical removal.

[0014] By applying a light field using an ultraviolet point light source in conjunction with stainless steel and quartz pillars, the light field intensity and uniformity are further improved, thereby enhancing photocatalytic efficiency, promoting oxidation modification of the wafer surface, and achieving high-quality and efficient polishing results when combined with mechanical grinding and polishing.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The polishing disc unit of the present invention is driven by a hollow turntable, and by installing LED beads with different emission angles such as 30°, 45° or 60°, the irradiance intensity can be adjusted over a wide range. 2. The light source of the LED lamp bead of the present invention is reflected by the stainless steel hole wall with holes and refracted by the quartz column before irradiating the surface of the wafer, which promotes the generation of electron-hole pairs on the surface of the wafer. Combined with the electric field applied by the center of the conductive thin film, it realizes efficient oxidation of the wafer surface and improves the material removal rate. 3. The workpiece unit of the present invention uses a conductive vacuum chuck to adsorb the wafer, drives it to move up and down by a cylinder and applies pressure to the wafer, and drives the workpiece unit to move horizontally by a horizontal guide rail. At the same time, combined with a trimming unit and a laser probe, it realizes online trimming and surface detection of the polishing pad, effectively improving the level of intelligence in the polishing process. Attached Figure Description

[0016] Figure 1 This is an overall schematic diagram of the device of the present invention; Figure 2 This is a schematic diagram of the workpiece unit of the present invention; Figure 3 This is a schematic diagram of the polishing disc unit of the present invention; Figure 4 This is a schematic diagram of the polishing disc unit structure of the present invention; Figure 5 This is a schematic diagram of the arrangement of the LED array in the polishing disc unit of the present invention; Figure 6 This is a schematic diagram of the radial arrangement of the LED beads in the polishing disc unit of the present invention; Figure 7 This is a schematic diagram of the device of the present invention; Figure 8 This is a flowchart of the method of the present invention.

[0017] In the diagram: 1. Machine tool base unit; 2. Workpiece unit; 3. Polishing disc unit; 4. Liquid supply unit; 5. Cylinder; 6. Horizontal guide rail; 7. Horizontal moving table; 8. Vertical guide rail; 9. Workpiece moving platform; 10. Dressing unit; 11. Laser probe; 12. Workpiece drive motor; 13. Coupling; 14. Conductive slip ring; 15. Connecting rod; 16. Universal adjustment platform; 17. Conductive vacuum chuck; 18. Wafer; 19. Polishing pad; 20. Transparent conductive film; 21. Perforated stainless steel disc; 22. Water-cooled disc; 23. Stainless steel tray; 24. Rotary shaft; 25. Electro-hydraulic slip ring; 26. Hollow rotary table; 27. Reducer; 28. Spindle motor; 29. ​​Conductive stainless steel sheet; 30. Quartz column; 31. Ultraviolet lamp bead. Detailed Implementation

[0018] The following will refer to the appendix. Figure 1-8 The present invention will be described in detail with reference to the embodiments.

[0019] Example 1 Please see Figure 1 This invention provides a photochemical mechanical polishing device and method based on quartz column light guiding. In the implementation of this invention, a 3W ultraviolet lamp bead 31 is used, which can provide ultraviolet light with a wavelength of 350nm.

[0020] In the process of establishing a photochemical mechanical polishing device and method based on quartz column light guide in this invention, firstly, the wafer 18 is adsorbed onto the universal adjustment platform 16 of the workpiece unit 2 by the conductive vacuum chuck 17. Polishing liquid is added by the liquid supply unit 4, so that the polishing liquid wets the surface of the wafer 18 and the surface of the polishing pad 19, completing the polishing pretreatment. The ultraviolet lamp bead 31 and the power supply are turned on, and the workpiece unit 2 is moved by the horizontal guide rail 6 and the vertical guide rail 8 to bring the wafer 18 close to the surface of the polishing pad 19. The workpiece unit 2, the polishing disk unit 3 and the polishing liquid form a photoelectrolysis cell. The wafer 18 and the polishing disk unit start the rotational motion to achieve polishing of the surface of the wafer 18. The processing object in this embodiment is a GaN wafer, and the selected lamp disk structure is an array arrangement. The method includes the following steps: S1, such as Figure 3-5 As shown, the perforated stainless steel disk 21 has uniformly distributed lamp holes with a diameter d = 10 mm. Ultraviolet (UV) LED beads 31 are installed in the lamp holes, and a transparent quartz column 30 is embedded above the UV LED beads 31, so that the angle of the UV light rays transmitted through the quartz column 30 is 30°. A transparent conductive film 20 and a conductive stainless steel sheet 29 are then attached above the perforated stainless steel disk 21 to apply an electric field. S2. The GaN wafer is adsorbed onto the universal adjustment platform 16 by a conductive vacuum chuck 17. The back of the conductive vacuum chuck 17 is connected to the positive terminal of the power supply through a conductive slip ring 14. The power supply voltage is 4V. S3. Polishing slurry is added dropwise through the liquid supply unit 4, allowing the polishing slurry to wet the surface of wafer 18 and polishing pad 19, completing the polishing pretreatment. The polishing slurry used is a 5wt% silica sol polishing slurry mixture with an abrasive particle size of 50–100 nm and a potassium sulfate aqueous solution with a molar concentration of 0.1 mol / L. S4. Turn on the ultraviolet lamp bead 31. The ultraviolet light is reflected and refracted by the perforated stainless steel disk 21 and the quartz column 30, and shines on the surface of the GaN wafer 18 through the light-transmitting hole on the polishing pad 19. The diameter of the light-transmitting hole is D=10mm. S5. Control the movement of the horizontal guide rail 6 and the vertical guide rail 8 to move the workpiece unit 2 to a suitable position above the polishing disk unit 3, so that the GaN wafer is close to the surface of the polishing pad 19. At this time, the polishing liquid wets the surface of the GaN wafer, and the negative terminal of the power supply is connected to the conductive stainless steel sheet 29 through the electro-hydraulic slip ring 25. The center discharges and conducts electricity through the conductive film 20. At this time, the GaN wafer is the anode, the polishing disk unit 3 is the cathode, and the workpiece unit 2, the polishing disk unit 3 and the polishing liquid form a photoelectrolysis cell, and the surface of the wafer 18 undergoes oxidation modification. S6. The workpiece drive motor 12 and the spindle motor 28 are started, with speeds of n1=60 rpm and n2=40 rpm respectively. The GaN wafer and the polishing pad start rotating. After 10 minutes of preheating, the cylinder 5 controls the GaN wafer surface to contact the polishing pad, realizing a photoelectrochemical mechanical polishing of the wafer 18 based on the light guide of the quartz pillar 30. Example 2 This embodiment is an example of a photochemical mechanical polishing device and method based on a quartz pillar 30 light guide. This embodiment is similar to Embodiment 1, except that the object being processed in this embodiment is SiC. This embodiment includes the following steps: S1, such as Figure 3-5 As shown, the perforated stainless steel disk 21 has uniformly distributed lamp holes with a diameter d = 10 mm. Ultraviolet (UV) LED beads 31 are installed in the lamp holes, and a transparent quartz column 30 is embedded above the UV LED beads 31, so that the angle of the UV light rays transmitted through the quartz column 30 is 30°. A transparent conductive film 20 and a conductive stainless steel sheet 29 are then attached above the perforated stainless steel disk 21 to apply an electric field. S2, SiC wafer 18 is adsorbed onto universal adjustment platform 16 by conductive vacuum chuck 17. The back of conductive vacuum chuck 17 is connected to the positive terminal of power supply through conductive slip ring 14. The power supply voltage is 4V. S3. Polishing slurry is added dropwise through the liquid supply unit 4, allowing the polishing slurry to wet the surface of the SiC wafer 18 and the surface of the polishing pad 19, thus completing the polishing pretreatment. The polishing slurry used is a 5wt% silica sol polishing slurry mixture with an abrasive particle size of 50–100 nm and a potassium sulfate aqueous solution with a molar concentration of 0.1 mol / L. S4. Turn on the ultraviolet lamp bead 31. The ultraviolet light is reflected and refracted by the perforated stainless steel disk 21 and the quartz column 30, and shines on the surface of the SiC wafer 18 through the light-transmitting hole on the polishing pad 19. The diameter of the light-transmitting hole is D=10mm. S5. Control the movement of the horizontal guide rail 6 and the vertical guide rail 8 to move the workpiece unit 2 to a suitable position above the polishing disk unit 3, so that the SiC wafer 18 is close to the surface of the polishing pad 19. At this time, the polishing liquid wets the surface of the SiC wafer 18, and the negative terminal of the power supply is connected to the conductive stainless steel sheet 29 through the electro-hydraulic slip ring 25. The center discharges and conducts electricity through the transparent conductive film 20. At this time, the SiC wafer is the anode, the polishing disk unit 3 is the cathode, and the workpiece unit 2, the polishing disk unit 3 and the polishing liquid form a photoelectrolysis cell, and the surface of the wafer 18 undergoes oxidation modification. S6. The workpiece drive motor 12 and the spindle motor 28 are started, with speeds of n1=60 rpm and n2=40 rpm respectively. The SiC wafer 18 and the polishing disk unit 3 start rotating. After 10 minutes of preheating, the cylinder 5 controls the surface of the wafer 18 to contact the polishing pad 19, thereby realizing a photoelectrochemical mechanical polishing of the wafer 18 based on the light guide of the quartz pillar 30. Example 3 This embodiment is similar to Embodiment 1, except that the lamp panel structure used in this embodiment is arranged radially. This embodiment includes the following steps: S1, such as Figure 6 As shown, the perforated stainless steel disk 21 has uniformly distributed lamp holes with a diameter d = 10 mm. Ultraviolet (UV) LED beads 31 are installed in the lamp holes, and a transparent quartz column 30 is embedded above the UV LED beads 31, so that the angle of the UV light rays transmitted through the quartz column 30 is 30°. A transparent conductive film 20 and a conductive stainless steel sheet 29 are then attached above the perforated stainless steel disk 21 to apply an electric field. S2, GaN wafer 18 is adsorbed onto universal adjustment platform 16 by conductive vacuum chuck 17. The back of conductive vacuum chuck 17 is connected to the positive terminal of power supply through conductive slip ring 14. The power supply voltage is 4V. S3. Polishing slurry is added dropwise through the liquid supply unit 4, allowing the polishing slurry to wet the surface of wafer 18 and polishing pad 19, completing the polishing pretreatment. The polishing slurry used is a 5wt% silica sol polishing slurry mixture with an abrasive particle size of 50–100 nm and a potassium sulfate aqueous solution with a molar concentration of 0.1 mol / L. S4. Turn on the ultraviolet lamp bead 31. The ultraviolet light is reflected and refracted by the perforated stainless steel disk 21 and the quartz column 30, and shines on the surface of the GaN wafer 18 through the light-transmitting hole on the polishing pad 19. The diameter of the light-transmitting hole is D=10mm. S5. Control the movement of the horizontal guide rail 6 and the vertical guide rail 8 to move the workpiece unit 2 to a suitable position above the polishing disk unit 3, so that the GaN wafer 18 is close to the surface of the polishing pad 19. At this time, the polishing liquid wets the surface of the GaN wafer 18, and the negative terminal of the power supply is connected to the conductive stainless steel sheet 29 through the electro-hydraulic slip ring 25. The center discharges and conducts electricity through the transparent conductive film 20. At this time, the GaN wafer is the anode, the polishing disk unit is the cathode, and the workpiece unit 2, the polishing disk unit 3 and the polishing liquid form a photoelectrolysis cell, and the surface of the wafer 18 undergoes oxidation modification. S6. The workpiece drive motor 12 and the spindle motor 28 are started, with speeds of n1=60 rpm and n2=40 rpm respectively. The GaN wafer and the polishing disk unit start rotating. After running for 10 minutes to preheat, and after the movement is stable, the cylinder 5 controls the surface of the GaN wafer 18 to contact the polishing pad 19, thereby realizing a photoelectrochemical mechanical polishing of the wafer 18 based on the light guide of the quartz pillar 30. Example 4 This embodiment is similar to Embodiment 2, except that the ultraviolet light source used in this embodiment is a 60° light source, and the lamp panel structure is arranged radially. This embodiment includes the following steps: S1, such as Figure 6 As shown, the perforated stainless steel disk 21 has uniformly distributed lamp holes with a diameter d = 10 mm. Ultraviolet (UV) LED beads 31 are installed in the lamp holes, and a transparent quartz column 30 is embedded above the UV LED beads 31, so that the UV light rays transmitted through the quartz column 30 have an angle of 60°. A transparent conductive film 20 and a conductive stainless steel sheet 29 are then attached above the perforated stainless steel disk 21 to apply an electric field. S2, SiC wafer 18 is adsorbed onto universal adjustment platform 16 by conductive vacuum chuck 17. The back of conductive vacuum chuck 17 is connected to the positive terminal of power supply through conductive slip ring 14. The power supply voltage is 4V. S3. Polishing slurry is added dropwise through the liquid supply unit 4, allowing the polishing slurry to wet the surface of the SiC wafer 18 and the surface of the polishing pad 19, thus completing the polishing pretreatment. The polishing slurry used is a 5wt% silica sol polishing slurry mixture with an abrasive particle size of 50–100 nm and a potassium sulfate aqueous solution with a molar concentration of 0.1 mol / L. S4. Turn on the ultraviolet lamp bead 31. The ultraviolet light is reflected and refracted by the perforated stainless steel disk 21 and the quartz column 30, and shines on the surface of the SiC wafer through the light-transmitting hole on the polishing pad 19. The diameter of the light-transmitting hole is D=10mm. S5. Control the movement of the horizontal guide rail 6 and the vertical guide rail 8 to move the workpiece unit 2 to a suitable position above the polishing disk unit 3, so that the SiC wafer 18 is close to the surface of the polishing pad 19. At this time, the polishing liquid wets the surface of the SiC wafer 18, and the negative terminal of the power supply is connected to the conductive stainless steel sheet 29 through the electro-hydraulic slip ring 25. The center discharges and conducts electricity through the transparent conductive film 20. At this time, the SiC wafer is the anode, the polishing disk unit is the cathode, and the workpiece unit 2, the polishing disk unit 3 and the polishing liquid form a photoelectrolysis cell, and the surface of the wafer 18 undergoes oxidation modification. S6. The workpiece drive motor 12 and the spindle motor 28 are started, with speeds of n1=60 rpm and n2=40 rpm respectively. The SiC wafer 18 and the polishing disk unit 3 start rotating. After 10 minutes of preheating, the cylinder 5 controls the surface of the wafer 18 to contact the polishing pad 19, thereby realizing a photoelectrochemical mechanical polishing of the wafer 18 based on the light guide of the quartz pillar 30. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photoelectrochemical mechanical polishing device based on light guiding of a quartz column, characterized in that: The polishing machine includes a machine base unit (1), a workpiece unit (2), a polishing disc unit (3), a liquid supply unit (4), a dressing unit (10) and a laser probe (11). The machine base unit (1) is a rectangular frame structure. The workpiece unit (2) is installed on the left side of the upper part of the machine base unit (1). The polishing disc unit (3) is installed on the right side of the upper part of the machine base unit (1). The liquid supply unit (4) is installed on the machine base unit (1) and located outside the polishing disc unit (3). The dressing unit (10) is installed on the machine base unit (1) and located outside the polishing disc unit (3). The laser probe (11) is installed on the dressing unit (10) and located above the polishing disc unit (3). The polishing disc unit (3), the workpiece unit (2) and the polishing liquid form a photoelectrochemical cell.

2. The photoelectrochemical mechanical polishing device based on the light guide of the quartz column according to claim 1, characterized in that: The workpiece unit (2) includes a horizontal guide rail (6), a horizontal moving table (7), a vertical guide rail (8), a workpiece moving platform (9), a cylinder (5), a workpiece driving motor (12), a conductive slip ring (14), a workpiece connecting rod (15), a coupling (13), a universal adjustment platform (16) and a conductive vacuum chuck (17). The horizontal guide rail (6) is installed on the left side of the workbench, and the workbench is installed on the machine base unit (1). The horizontal moving table (7) is in sliding connection with the horizontal guide rail (6). The vertical guide rail (8) is installed on the inner side of the horizontal moving table (7). The workpiece moving platform (9) is in sliding connection with the vertical guide rail (8). The cylinder (5) is installed on the horizontal moving table (7). The piston rod of the cylinder (5) is connected with the workpiece moving platform (9) to drive the workpiece moving platform (9) to ascend and descend. The workpiece driving motor (12) is fixed on the upper surface of the workpiece moving platform (9). The workpiece driving motor (12) is connected with the universal adjustment platform (16) through the coupling (13) and the workpiece connecting rod (15). The conductive vacuum chuck (17) is installed on the universal adjustment platform (16). The lower side of the conductive vacuum chuck (17) adsorbs a wafer (18). The conductive slip ring (14) is fixed on the lower side of the workpiece moving platform (9) through the workpiece connecting rod (15).

3. The photoelectrochemical mechanical polishing device based on the light guide of the quartz column according to claim 1, characterized in that: The polishing disc unit (3) comprises a hollow rotary table (26), a speed reducer (27), a main shaft motor (28), an electro-hydraulic slip ring (25), a stainless steel tray (23), a rotating shaft (24), a water-cooled disc (22), a perforated stainless steel disc (21), an ultraviolet light bead (31), a quartz column (30), a polishing pad (19), a transparent conductive film (20), and a conductive stainless steel sheet (29); the base of the hollow rotary table (26) is mounted in a workbench, the power side of the hollow rotary table (26) is connected with the main shaft motor (28) through the speed reducer (27), and the load side of the hollow rotary table (26) is connected with the stainless steel tray (23) through the rotating shaft (24); the stainless steel tray (23) is internally provided with the water-cooled disc (22), and the perforated stainless steel disc (21) is mounted on the upper portion of the stainless steel tray (23); the perforated stainless steel disc (21) is provided with lamp holes arranged in an array or in a radial manner, the ultraviolet light bead (31) is mounted in the lamp holes, and the quartz column (30) is embedded above the ultraviolet light bead (31) to guide light; the transparent conductive film (20), the conductive stainless steel sheet (29), and the polishing pad (19) are sequentially mounted on the upper portion of the perforated stainless steel disc (21) from bottom to top; and the electro-hydraulic slip ring (25) is mounted on the lower portion of the rotating shaft (24).

4. The photoelectrochemical mechanical polishing device based on the light guide of the quartz column according to claim 1, characterized in that: The laser measuring head (11) is used for real-time online monitoring of the surface shape of the polishing pad (19); and the trimming unit (10) is used for trimming the surface shape of the polishing pad (19).

5. The photoelectrochemical mechanical polishing device based on the light guide of the quartz column according to claim 3, characterized in that: The conductive stainless steel sheet (29) is connected with the electro-hydraulic slip ring (25) for conduction, the wafer (18) is connected with the conductive slip ring (14) through the conductive vacuum chuck (17) for conduction, and an electric field is applied.

6. The photoelectrochemical mechanical polishing device based on the light guide of the quartz column according to claim 3, characterized in that: The ultraviolet light bead (31) has an emission angle of 30°, 45°, or 60°.

7. An electrochemical mechanical polishing method based on quartz column light guiding, the method is performed by using the electrochemical mechanical polishing device based on quartz column light guiding according to any one of claims 1-7, and comprises the following steps: S1: the wafer (18) is adsorbed on the universal adjustment platform (16) of the workpiece unit (2) through the conductive vacuum chuck (17), and the polishing liquid is dropped by the liquid supply unit (4) to immerse the wafer (18) surface and the polishing pad (19) surface, and the polishing pretreatment is completed; S2: the wafer (18) is moved close to the polishing pad (19) surface by moving the workpiece unit (2) through the horizontal guide rail (6) and the vertical guide rail (8), so that the polishing disc unit (3), the workpiece unit (2), and the polishing liquid form a photoelectric cell; S3: the workpiece driving motor (12) and the main shaft motor (28) are started, the wafer (18) and the polishing disc start rotary motion, and the wafer (18) is brought into contact with the polishing pad (19) surface by controlling the air cylinder (5); S4: the irradiation intensity of the ultraviolet light and the electric field parameters are controlled, so that the wafer (18) surface is subjected to controllable oxidation modification under the action of the photoelectrochemical reaction of the photoelectric cell to form an easily removable oxide layer; meanwhile, the relative rotary motion between the polishing disc unit (3) and the wafer (18) is utilized to remove the oxide layer of the wafer (18) layer by layer through mechanical grinding to realize the super-smooth planarization processing of the wafer (18) surface; S5: The laser measuring head (11) monitors the surface shape of the polishing pad (19) in real time online, and the trimming unit (10) trims the polishing pad (19) to meet the processing requirements.

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