A monolithic wafer wet etching apparatus and method

Abstract

This invention belongs to the field of semiconductor manufacturing technology and discloses a monolithic wafer wet etching apparatus and method. The apparatus includes a process chamber, a wafer carrier and rotation module, a fluid distribution module, a control unit, and an optical monitoring unit. The wafer carrier and rotation module is equipped with a thermally adjustable chuck with concentric annular protrusions and a temperature-controlled flow channel, and an annular gas barrier ring capable of spraying inert gas below the wafer edge. The fluid distribution module integrates a central main nozzle, auxiliary nozzles, and a gas curtain nozzle. This method fixes the wafer to the chuck to form a gas barrier, drives its rotation, and sprays a chemical solution to form a uniform liquid film. Simultaneously, the optical monitoring unit monitors the film thickness in real time to determine the etching endpoint and quickly switches the chemical solution for rinsing and drying. This invention achieves high uniformity in etching and heat transfer, effectively prevents over-etching at the edges, and improves process flexibility, cleanliness, and controllability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more specifically to a single-wafer wet etching apparatus and method. Background Technology

[0002] Wet etching, a key surface treatment technology in semiconductor chip manufacturing, boasts advantages such as isotropy, high selectivity, and low cost. Equipment for wet etching is mainly divided into two types: batch processing and monolithic. While batch processing equipment offers higher throughput, it also suffers from drawbacks such as difficulty in controlling uniformity, high reagent consumption, high risk of cross-contamination, and difficulty in integrating into automated production lines, thus failing to meet the requirements of advanced processes. Monolithic equipment processes one wafer at a time, achieving excellent etching uniformity and process repeatability while reducing contamination risks, better adapting to the demands of advanced processes. However, this technology still faces several challenges: the reagents are corrosive to the equipment and may cause particulate contamination; the wafer fixing method can easily create shadow areas, affecting the uniformity of etching and heat transfer; the process changeover process is complex, with long preset times, and defects are easily introduced during multi-step processing; furthermore, insufficient real-time in-situ monitoring capabilities lead to fluctuations in etching results.

[0003] Therefore, there is an urgent need for an improved single-wafer wet etching equipment that can effectively solve problems related to reagent management, wafer fixation and heat transfer, process flexibility and real-time monitoring while ensuring high uniformity and high throughput. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of existing technologies and provide a single-wafer wet etching apparatus and method. This apparatus achieves precise, stable, efficient, and flexible control of the wet etching process through the integration of an innovative chuck design, a multi-level fluid management system, modular process chambers, and an in-situ monitoring unit.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A single-wafer wet etching apparatus includes a rack (1), a process chamber (2), a wafer carrier and rotation module (3), a fluid distribution module (5), an exhaust and treatment system (7), a control unit (8), and an optical monitoring unit (9); wherein, the process chamber (2) is fixedly installed on the upper part of the rack (1), and the wafer carrier and rotation module (3) is provided inside the lower part of the process chamber (2); the fluid distribution module (5) is installed on the inner top wall of the process chamber (2); the exhaust and treatment system (7) is connected to the top of the process chamber (2) through a pipeline; the control unit (8) is electrically connected to the wafer carrier and rotation module (3), the fluid distribution module (5), and the exhaust and treatment system (7); the optical monitoring unit (9) is installed on the lower left side of the outside of the process chamber (2).

[0007] Furthermore, the wafer carrying and rotating module (3) includes a spindle (31), a motor (32), a thermal adjustment chuck (33), and an annular gas barrier ring (34); the motor (32) is fixed on the frame (1), and its output shaft is driven to the lower end of the spindle (31); the thermal adjustment chuck (33) is fixed on the upper end of the spindle (31) to adsorb and support the wafer (4); the annular gas barrier ring (34) is coaxially fixedly sleeved on the outer periphery of the thermal adjustment chuck (33) to form a local positive pressure gas barrier below the edge of the wafer (4).

[0008] Furthermore, the thermal regulating chuck (33) is an electrostatic chuck, and its upper surface (331) is provided with concentric annular protrusions (332), and a fluid flow channel (333) is integrated inside it; the concentric annular protrusions (332) form annular line contact with the back of the wafer (4); the fluid flow channel (333) is circulated with a heat-conducting medium to control the temperature of the wafer (4).

[0009] Furthermore, the annular gas barrier ring (34) is provided with an annular cavity (341) inside, and a micropore array (342) communicating with the annular cavity (341) is opened on the inner ring wall surface; the annular cavity (341) is connected to an external pipeline through a rotary joint (343), which connects and communicates the rotating annular cavity (341) with the fixed external pipeline, and the external pipeline is connected to an external gas source.

[0010] Furthermore, the micropore array (342) has a pore size of 50 μm to 200 μm and a pore density of 5 to 20 pores per square centimeter.

[0011] Furthermore, the fluid distribution module (5) is provided with a central main nozzle (51), auxiliary nozzles (52) and an air curtain nozzle (53); the central main nozzle (51) is fixedly installed on the inner top wall of the process chamber (2) and located on its central axis, and its liquid inlet end is connected to the liquid supply system through a pipeline; the auxiliary nozzles (52) are evenly distributed around the central main nozzle (51); the air curtain nozzle (53) is arranged around the central main nozzle (51) and sprays inert gas downward to form an annular air curtain.

[0012] Furthermore, the central main nozzle (51) is a retractable design, and it integrates a first temperature sensor and a first conductivity sensor.

[0013] Furthermore, the optical monitoring unit (9) is a laser interferometer, whose monitoring beam is incident on the surface of the wafer (4) through the optical monitoring window (24) set on the side wall of the process chamber (2) to monitor the thickness change of the thin film on the surface of the wafer (4) in real time.

[0014] The present invention also provides a single-wafer wet etching method for use in the above-mentioned equipment, comprising the following steps: Step S1: Wafer loading and preparation: The wafer (4) with the thin film to be etched on its surface is transferred to the thermal adjustment chuck (33) and fixed by adsorption; an inert gas is introduced into the annular gas barrier ring (34), and the inert gas is ejected from the micro-hole array (342) to form a gas barrier below the edge of the wafer (4); Step S2: Process parameter setting and preheating: Set the process parameters and start the temperature control function of the thermal chuck (33) to preheat the wafer (4) to the target temperature; Step S3: Etching process execution: drive the wafer (4) to rotate at a first rotation speed; supply etching solution to the surface of the rotating wafer (4); at the same time, monitor the thickness of the thin film on the surface of the wafer (4) in real time through the optical monitoring unit (9); Step S4: Etching endpoint judgment and solution switching: When the etching endpoint is determined based on real-time monitoring data, the etching solution is turned off and the supply of deionized water is switched. At the same time, the wafer (4) speed is adjusted to the second speed for rinsing. Step S5: Rotary drying and gas assistance: Stop supplying deionized water, increase the rotation speed of the wafer (4) to the third rotation speed for rotary drying; at the same time, increase the gas flow rate of the annular gas barrier ring (34), and spray inert gas through the gas curtain nozzle (53) to accelerate drying; Step S6: Wafer unloading: Stop the rotation of wafer (4) and related functions, and remove the processed wafer (4).

[0015] Further, in step S3, the first rotational speed is 100-500 rpm; in step S4, the second rotational speed is 600-1200 rpm; and in step S5, the third rotational speed is 1500-3000 rpm.

[0016] Furthermore, in step S4, the determination of the etching endpoint is preset to be when the film thickness drops to 1 nm to 10 nm, so as to achieve automatic stopping by utilizing the difference in etching selectivity of different materials in the extremely thin state.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By using a heat-regulating chuck with concentric ring protrusions to fix the wafer in a ring-shaped line contact manner, the contact area and shadow effect are greatly reduced. Combined with the internal fluid flow channel for precise temperature control, the temperature in the wafer surface is highly uniform. At the same time, the local positive pressure gas barrier formed by the ring gas barrier ring below the edge of the wafer effectively prevents the liquid and vapor from invading the back or edge of the wafer, avoiding excessive edge etching, thus achieving a highly uniform etching and heat transfer effect overall.

[0018] (2) The equipment adopts a multi-level gas and fluid management strategy. The inert gas curtain formed by the gas curtain nozzle can suppress the rise of mist and the fall of particles in the cavity; the annular gas barrier ring protects the wafer carrying area; these measures together provide a clean process environment for advanced processes.

[0019] (3) The fluid distribution module adopts a modular design, integrating a central main nozzle and multiple auxiliary nozzles, which can quickly supply and switch different types of etching solutions, reaction enhancers or deionized water, support complex multi-step process sequences, and have a rapid switching response. The transparent process chamber is easy to observe and maintain. These designs together improve the process flexibility and overall capacity of the equipment.

[0020] (4) By integrating the in-situ monitoring unit, including the first temperature sensor and the first conductivity sensor integrated in the central main nozzle, and the corresponding laser interferometer outside the side wall optical monitoring window, the physical state of the supplied solution and the thickness change of the wafer surface film can be monitored in real time. This data is fed back to the control unit in real time, which can realize accurate etching endpoint judgment, dynamic adjustment of process parameters and closed-loop control, greatly improving the repeatability of process results and product yield. Attached Figure Description

[0021] Figure 1 This is a schematic diagram (cross-sectional view) of the overall structure of the monolithic wafer wet etching equipment in an embodiment of the present invention. Figure 2 for Figure 1 A partially enlarged schematic diagram of the wafer carrier and rotation module; Figure 3 This is a top view of the upper surface structure of the thermally adjustable chuck in an embodiment of the present invention; Figure 4 This is a schematic diagram (cross-sectional view) of the annular gas barrier ring in an embodiment of the present invention. Figure 5 This is a schematic flowchart of a single-wafer wet etching method in an embodiment of the present invention.

[0022] The components include: 1. Frame; 2. Process chamber; 21. Top opening; 22. Bottom drain port; 23. Automatic opening and closing cover; 24. Optical monitoring window; 3. Wafer carrying and rotation module; 31. Spindle; 32. Motor; 33. Thermal regulating chuck; 331. Upper surface of thermal regulating chuck; 332. Concentric annular protrusion; 333. Fluid channel; 34. Annular gas barrier ring; 341. Annular cavity; 342. Micropore array; 343. Rotary joint; 4. Wafer; 5. Fluid distribution module; 51. Central main nozzle; 52. Auxiliary nozzle; 53. Gas curtain nozzle; 7. Exhaust and treatment system; 8. Control unit; 9. Optical monitoring unit; 91. Laser interferometer. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] Example 1: See Figures 1 to 4 This embodiment provides a high-performance single-wafer wet etching device for 300 mm wafers, which has the functions of chemical solution circulation and real-time endpoint detection.

[0025] The entire equipment is mounted on a sturdy frame 1 welded from stainless steel profiles, with a chemical corrosion resistant coating on its surface. Internally, it integrates the power supply cabinet, gas path control panel, and some control unit hardware 8. The process chamber 2 is fixed to the upper part of the frame 1. Its main body is constructed from a single injection-molded high-purity transparent poly(fluoroethylene propylene) (PFA) cylindrical tube with a wall thickness of 15 mm, an inner diameter of 400 mm, and a height of 350 mm. It exhibits excellent acid corrosion resistance and a light transmittance greater than 92%. The upper end of the process chamber 2 has a top opening 21 with a diameter of 220 mm. An automatically opening and closing cover 23, controlled by the control unit 8 and driven by a linear motor, is located at the opening. Fluororubber sealing rings are embedded in the edges of the cover for sealing. The lower end of the process chamber 2 has a conical bottom drain port 22 with a diameter of 50 mm, connected by a PFA flange. A 30 mm diameter optical monitoring window 24 is opened on the side wall of the process chamber 2, and is sealed with 8 mm thick fused silica glass via laser welding.

[0026] The wafer carrier and rotation module 3 is located inside the lower part of the process chamber 2; a brushless DC servo motor 32 with a rated power of 200 W is fixed on the frame 1 and installed directly below the chamber via a magnetohydrodynamic rotary sealing flange, driving a spindle 31 made of Hastelloy with a diameter of 30 mm to rotate; a thermally adjustable chuck 33 is fixed to the upper end of the spindle 31. In this embodiment, the chuck adopts an electrostatic adsorption (ESC) type, and its substrate is aluminum nitride ceramic; the upper surface 331 of the thermally adjustable chuck is precision ground and polished, and etched with three concentric annular protrusions 332, with a protrusion height of 50 μm and a top width of 100 μm, so that it can be connected to the 300 The contact area on the back side of the 4mm wafer is less than 0.5%; the thermal regulating chuck 33 has a spiral fluid flow channel 333 internally processed, which is connected to an external high-precision heat transfer fluid temperature control system via a rotary joint 343, enabling precise temperature control within the range of -10°C to 90°C; the thermal regulating chuck 33 also has an embedded electrostatic adsorption electrode connected to a high-voltage DC power supply; the annular gas barrier ring 34, coaxially fixed and sleeved around the outer periphery of the thermal regulating chuck 33, is made of PFA and fixed by an insulating bracket, with its upper surface flush with the upper surface 331 of the thermal regulating chuck; the ring has a rectangular cross-section annular cavity 341 inside, and two rows of micro-hole arrays 342 are processed on its inner ring wall (facing the edge of the 4mm wafer), with the aperture of the micro-hole array 342 being 100mm. μm, with a pore density of 10 per square centimeter, and the micropore axis is slightly tilted outward at 5°; the annular cavity 341 is connected to a high-purity nitrogen gas source (purity >99.999%) via a rotary joint 343, which is equipped with a mass flow controller and a temperature control unit.

[0027] The fluid distribution module 5 is installed on the inner top wall of the process chamber 2; the central main nozzle 51 located on the central axis is made of PFA material with an outer diameter of 8 mm. Its end integrates a piezoelectric ceramic actuator that can achieve ±2 mm extension and retraction. A miniature platinum resistance temperature sensor and a four-electrode conductivity sensor are embedded inside near the outlet. The sensor probe has a streamlined design; four identical PFA auxiliary nozzles 52 are evenly distributed on a circumference with a diameter of 100 mm and can be connected to different liquids respectively; an annular slit gas curtain nozzle 53 is provided around the central main nozzle 51 and the auxiliary nozzles 52. The slit is 0.5 mm wide and tilted downward at 30°, and is connected to another path of temperature-controlled high-purity nitrogen.

[0028] The exhaust and treatment system 7 includes a corrosion-resistant fan that draws air from the top of the process chamber 2 to maintain a slight negative pressure (approximately -10 Pa). The exhaust gas is treated by a condenser, a two-stage scrubbing tower (water washing and alkaline washing), and a HEPA filter before being discharged. The optical monitoring unit 9 is located on the lower left side of the outside of the process chamber 2 and includes a laser interferometer 91 (670 nm). Its beam illuminates the wafer surface through the optical monitoring window 24 set on the side wall of the process chamber 2 to measure the thin film thickness change in real time. The control unit 8 adopts an "industrial PC + real-time PLC" architecture and integrates dedicated software to realize the control and monitoring of the entire equipment through high-speed bus (EtherCAT) communication.

[0029] Example 2: This embodiment details the process of precisely etching a 300 mm silicon wafer with a 100 nm thermally oxidized SiO2 film on its surface using the equipment of Embodiment 1 (see Embodiment 1). Figure 5 The details are as follows: Step S1: Equipment preparation and wafer loading The equipment is in standby mode, and the preset temperature of the thermal chuck 33 is 23°C. The control unit 8 drives the automatic opening and closing cover 23 to open. Then, the plant robot takes a 300 mm silicon wafer 4 with a 100 nm thermally oxidized SiO2 film on its surface from the FOUP and precisely places it on the upper surface of the thermal chuck 33 in the process chamber 2 and fixes it with adsorption. At this time, the gap between the edge of the wafer 4 and the inner wall of the annular gas barrier ring 34 is about 2 mm. After the robot withdraws, the control unit 8 activates the electrostatic adsorption function of the thermal chuck 33 to fix the wafer 4, applies a DC voltage greater than 1500 V, and then closes the automatic opening and closing cover 23 to seal the process chamber 2. At the same time, inert gas is introduced into the annular gas barrier ring 34, and dry nitrogen is uniformly sprayed out from the micropore array 342 to form a stable local positive pressure gas barrier below the edge of the wafer.

[0030] Step S2: Setting process parameters and preheating The operator selects the preset "DHF SiO2Etch" process formula through the human-machine interface, sets the etching steps, uses 200:1 diluted hydrofluoric acid supplied by the central main nozzle 51 at a flow rate of 800 ml / min, sets the target temperature of wafer 4 to 23.0°C and the spindle rotation speed to 400 rpm (within the first rotation speed range of 100-500 rpm), uses ultrapure deionized water supplied by the auxiliary nozzle at a flow rate of 1000 ml / min for 20 seconds at a rotation speed of 800 rpm (within the second rotation speed range of 600-1200 rpm), and in the drying step, increases the nitrogen flow rate of the annular gas barrier ring 34 to 10 SLM, the nitrogen flow rate of the gas curtain nozzle 53 is temperature controlled at 20 SLM, and the spindle speed is increased to 2500 rpm (within the third rotation speed range of 1500-3000 rpm) for 30 seconds. After the parameters are set, the control unit 8 activates the temperature control loop of the thermally regulating chuck 33 to stabilize the temperature of wafer 4 at the target value of 23.0°C.

[0031] Step S3: Etching process execution and real-time monitoring Control unit 8 instructs spindle motor 32 to drive wafer 4 to rotate at a uniform speed of 400 rpm. At the same time, the valve and pump of central main nozzle 51 are opened to spray DHF etching solution at 23.0°C onto the center of wafer 4 surface at a set flow rate. Under the action of centrifugal force, the solution spreads rapidly to form a uniform thin film. The laser interferometer 91 of optical monitoring unit 9 starts to work. Its beam is focused on a specific measurement point on the wafer surface through optical monitoring window 24 to monitor the change in SiO2 film thickness in real time. The data is synchronously fed back to control unit 8 for processing, graphical display and real-time etching rate calculation.

[0032] Step S4: Etching endpoint determination and rapid rinsing The endpoint detection algorithm within the control unit 8 continuously analyzes the thickness data transmitted back by the laser interferometer 91. When it is determined that the remaining thickness of the SiO2 film has dropped to 1 nm (within the range of 1 nm to 10 nm), the etching endpoint is determined by utilizing the difference in etching selectivity between silicon dioxide and the underlying silicon in an extremely thin state. The DHF solution supply is immediately shut off within a response time of less than 50 ms to effectively prevent over-etching of the underlying silicon. Subsequently, the control unit opens the deionized water auxiliary nozzle valve within a delay of less than 100 ms and sprays DIW onto the wafer surface at a high flow rate of 1000 ml / min. At the same time, the wafer rotation speed is increased to 800 rpm for a 20-second strong rinse to quickly remove residual solution and reaction products.

[0033] Step S5: High-speed rotary drying with gas assistance After the rinsing step is completed, the control unit 8 shuts off the deionized water supply and instructs the spindle motor to accelerate the wafer rotation speed from 800 rpm to 2500 rpm within 5 seconds, using centrifugal force to remove most of the liquid droplets on the surface; at the same time, the nitrogen flow rate of the annular gas barrier ring 34 is increased to 10 SLM and the air curtain nozzle 53 is opened to spray 20 SLM of 25°C warm nitrogen. Through the combined action of rotation and spin drying and the coordinated airflow from top to bottom, the residual liquid film in the wafer edge and surface microstructure is completely removed, achieving complete and traceless drying in 30 seconds.

[0034] Step S6: Wafer Unloading and Post-processing After the drying step is completed, the spindle stops rotating. The control unit 8 sequentially shuts down the electrostatic adsorption function and temperature control function of the thermal regulating chuck 33, the gas supply of the annular gas barrier ring 34 and the gas curtain nozzle 53, and then the automatic opening and closing cover 23 opens. The robot enters the process chamber 2 to take out the processed dried wafer 4 and transfer it back to FOUP.

[0035] Through the above process, high-precision and high-uniformity etching of SiO2 thin films was achieved, with the measured in-plane uniformity (1σ) being better than 1.2%, and the excessive etching at the edges and the generation of water stains after drying were effectively avoided.

[0036] Example 3: This embodiment is for back-side cleaning of 300 mm wafers with TSV patterns on the back side. The equipment is adjusted based on the first embodiment: the thermal regulation chuck 33 is replaced with a multi-zone temperature-controlled vacuum adsorption chuck; its substrate is anodized aluminum with a ceramic coating sprayed on the surface, and the internal fluid channel 333 is divided into three independent loops: a central circular area (100 mm in diameter), an intermediate ring area (50 mm wide), and an edge ring area (25 mm wide), each connected to an independent temperature control module, which can set different temperatures to compensate for the thermal unevenness caused by the pattern and ensure overall temperature uniformity (within ±0.5℃); vacuum adsorption is adopted, and the chuck surface is provided with an adsorption hole array connected to a vacuum generator.

[0037] The cleaning process is as follows: First, the wafer is loaded and vacuum-adsorbed for fixation. Then, the multi-zone temperature-controlled thermal chuck 33 is activated to heat the back of the wafer to the set temperatures (45°C in the center zone, 47°C in the middle ring zone, and 45°C in the edge zone) to ensure in-plane thermal uniformity. After the cleaning process begins, the wafer 4 is sprayed with diluted APM (SC-1) solution for 60 seconds by an auxiliary nozzle 52 at a speed of 300 rpm (within the first speed range of 100-500 rpm) to remove organic contaminants and particles. Then, it is switched to ultrapure water (DIW) for a brief 10-second rinse, while the speed is increased to 800 rpm (within the second speed range of 600-1200 rpm). Next, while maintaining the speed of 800 rpm, it is switched to another auxiliary nozzle 52 to spray diluted HPM (SC-2) solution for 60 seconds to remove metal ion contamination. After that, a 60-second rinse is performed at a speed of 1000 rpm (within the second speed range of 600-1200 rpm). The wafer is rinsed with a high flow rate of ultrapure water (within the rpm range) to ensure that chemical residues are completely removed. In the final drying step, the wafer speed is increased to 2000 rpm (within the third speed range of 1500-3000 rpm), and airflow from the annular gas barrier ring 34 and the gas curtain nozzle 53 is used to complete the drying and wafer unloading.

[0038] Throughout the cleaning, rinsing, and drying process, the annular gas barrier ring 34 continuously introduces gas, effectively preventing the chemical solution from penetrating the deep holes and gaps in the TSV pattern; the independent multi-zone temperature control system precisely compensates for the heat dissipation differences caused by the pattern, ensuring temperature uniformity in the process; and the modular fluid distribution design strongly supports the rapid and reliable execution of the above-mentioned complex multi-chemical liquid, multi-step cleaning sequence.

[0039] The present invention and its embodiments have been described above. This description is not restrictive. The accompanying drawings are only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the spirit of the present invention, such design should fall within the protection scope of the present invention.

Claims

1. A single-wafer wet etching apparatus, characterized in that, The system includes a rack (1), a process chamber (2), a wafer carrier and rotation module (3), a fluid distribution module (5), an exhaust and treatment system (7), a control unit (8), and an optical monitoring unit (9). The process chamber (2) is fixedly mounted on the upper part of the rack (1), with the wafer carrier and rotation module (3) located below it. The fluid distribution module (5) is located on the inner top wall of the process chamber (2). The exhaust and treatment system (7) is connected to the top of the process chamber (2) via a pipeline. The control unit (8) is connected to the wafer carrier and rotation module (3), the fluid distribution module (5), and the exhaust and treatment system. (7) Electrical connection; the optical monitoring unit (9) is located on the lower left side of the process chamber (2); the wafer carrying and rotating module (3) includes a spindle (31), a motor (32), a thermal adjustment chuck (33) and an annular gas barrier ring (34); the motor (32) is fixed on the frame (1), and its output shaft is driven to the lower end of the spindle (31); the thermal adjustment chuck (33) is fixed on the upper end of the spindle (31) to adsorb and support the wafer (4); the annular gas barrier ring (34) is coaxially fixed on the outer periphery of the thermal adjustment chuck (33) to form a local positive pressure gas barrier below the edge of the wafer (4).

2. The single-wafer wet etching equipment according to claim 1, characterized in that, The thermal regulation chuck (33) is an electrostatic chuck, and its upper surface (331) is provided with concentric annular protrusions (332), and a fluid flow channel (333) is integrated inside it; the concentric annular protrusions (332) form annular line contact with the back of the wafer (4); the fluid flow channel (333) is circulated with a heat-conducting medium to control the temperature of the wafer (4).

3. The single-wafer wet etching equipment according to claim 1, characterized in that, The annular gas barrier ring (34) has an annular cavity (341) inside, and a micropore array (342) communicating with the annular cavity (341) is opened on the inner ring wall. The annular cavity (341) is connected to an external pipeline through a rotary joint (343). The rotary joint (343) connects and communicates the rotating annular cavity (341) with the fixed external pipeline, and the external pipeline is connected to an external gas source.

4. The single-wafer wet etching equipment according to claim 3, characterized in that, The micropore array (342) has a pore size of 50 μm to 200 μm and a pore density of 5 to 20 pores per square centimeter.

5. The single-wafer wet etching equipment according to claim 4, characterized in that, The fluid distribution module (5) includes a central main nozzle (51), auxiliary nozzles (52) and an air curtain nozzle (53); the central main nozzle (51) is fixedly installed on the inner top wall of the process chamber (2) and located on its central axis, and its liquid inlet end is connected through a pipeline; the auxiliary nozzles (52) are evenly distributed around the central main nozzle (51); the air curtain nozzle (53) is arranged around the central main nozzle (51) and sprays inert gas downward to form an annular air curtain.

6. The single-wafer wet etching equipment according to claim 5, characterized in that, The central main nozzle (51) is a retractable design, and it integrates a first temperature sensor and a first conductivity sensor.

7. A single-wafer wet etching apparatus according to claim 6, characterized in that, The optical monitoring unit (9) is a laser interferometer, whose monitoring beam is incident on the surface of the wafer (4) through the optical monitoring window (24) set on the side wall of the process chamber (2).

8. A single-wafer wet etching method applied to the apparatus of any one of claims 7, characterized in that, Includes the following steps: Step S1: Wafer loading and preparation: The wafer (4) with the thin film to be etched on its surface is transferred to the thermal adjustment chuck (33) and fixed by adsorption; an inert gas is introduced into the annular gas barrier ring (34), and the inert gas is ejected from the micro-hole array (342) to form a gas barrier below the edge of the wafer (4); Step S2: Process parameter setting and preheating: Set the process parameters and start the temperature control function of the thermal chuck (33) to preheat the wafer (4) to the target temperature; Step S3: Etching process execution: drive the wafer (4) to rotate at a first rotation speed; supply etching solution to the surface of the rotating wafer (4); at the same time, monitor the thickness of the thin film on the surface of the wafer (4) in real time through the optical monitoring unit (9); Step S4: Etching endpoint judgment and solution switching: When the etching endpoint is determined based on real-time monitoring data, the etching solution is turned off and the supply of deionized water is switched. At the same time, the wafer (4) speed is adjusted to the second speed for rinsing. Step S5: Rotary drying and gas assistance: Stop supplying deionized water, increase the rotation speed of the wafer (4) to the third rotation speed for rotary drying; at the same time, increase the gas flow rate of the annular gas barrier ring (34), and spray inert gas through the gas curtain nozzle (53) to accelerate drying; Step S6: Wafer unloading: Stop the rotation of wafer (4) and related functions, and remove the processed wafer (4).

9. A single-wafer wet etching method according to claim 8, characterized in that, In step S3, the first rotational speed is 100-500 rpm; in step S4, the second rotational speed is 600-1200 rpm; and in step S5, the third rotational speed is 1500-3000 rpm.

10. A single-wafer wet etching method according to claim 8, characterized in that, In step S4, the etching endpoint is preset to be determined when the film thickness drops to 1 nm to 10 nm, so as to automatically stop the etching by taking advantage of the difference in etching selectivity of different materials in the extremely thin state.

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