-100 ℃ low-temperature ALE etching equipment based on He gas refrigeration closed-loop control

Abstract

The application discloses a kind of-100 ℃ low temperature ALE etching equipment based on He gas refrigeration closed loop control, it is related to semiconductor advanced manufacturing equipment technical field, including reaction cavity, He gas low temperature refrigeration system, ESC low temperature chuck module, temperature closed loop control system and particle inhibition module, the left side of reaction cavity is connected He gas low temperature refrigeration system by pipeline, He gas low temperature refrigeration system includes cryogenic pump, He gas storage tank, high-pressure compressor, heat exchanger and throttle valve;Particle inhibition module includes cryogenic water vapor trap and anti-particle backflow structure;The right side of reaction cavity is connected with worm gear molecular pump in series cryogenic water vapor trap, and the top of reaction cavity is provided with ICP plasma source.The application system is strong in compatibility, ESC dielectric layer adapts low temperature environment, there is no risk of embrittlement breakdown, refrigeration system can output 5-18kW refrigerating capacity, adapts the heat load demand of different processes such as 3DNAND, MRAM.

Description

Technical Field

[0001] This invention relates to the field of advanced semiconductor manufacturing equipment technology, and in particular to a -100°C low-temperature ALE etching equipment based on He gas cooling closed-loop control. Background Technology

[0002] As semiconductor devices evolve towards 3D NAND (128L and above), DRAM 1z / 1y nodes, and 3nm logic processes, high aspect ratio (HAR) etching places stringent demands on process anisotropy, sidewall passivation, and defect density. Low-temperature ALE etching, by lowering the wafer temperature to below -100°C, can effectively suppress lateral diffusion, enhance sidewall passivation, and reduce scalloping effects, becoming a core technology for advanced processes.

[0003] 1. Insufficient ability to meet low temperature standards: Traditional ethylene glycol-based cooling systems can only reach -70°C, and although mixed refrigerant systems can approach -90°C, they cannot stably maintain the extremely low temperature of -100°C, and the cooling response speed is slow (>5s), making it difficult to match the dynamic thermal load of ALE periodic etching. 2. Poor temperature control accuracy and uniformity: The lack of closed-loop coordination between cooling capacity and temperature monitoring, and the plasma energy load (8-15kW for 3D NAND and 2kW for MRAM) cause ESC chuck temperature fluctuations of more than ±5℃, affecting etching consistency; 3. Severe interference from particles and water vapor: Water vapor in the cavity is prone to condensation at extremely low temperatures, and reacts with F plasma to generate AlF3 particles. Furthermore, traditional vacuum systems cannot effectively suppress particle backflow, leading to an increase in device defect density. Insufficient system compatibility: The existing cooling system is disconnected from the thermal conduction design of the ESC chuck, and the dielectric layer is prone to breakdown due to low-temperature embrittlement. In addition, the cooling system is bulky and has low integration. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art, and to propose a -100℃ low temperature ALE etching device based on He gas cooling closed-loop control.

[0005] To address the problems existing in the prior art, the present invention adopts the following technical solution: A -100℃ low-temperature ALE etching apparatus based on He gas refrigeration closed-loop control includes a reaction chamber, a He gas low-temperature refrigeration system, an ESC low-temperature chuck module, a temperature closed-loop control system, and a particle suppression module. The left side of the reaction chamber is connected to a cryogenic He gas refrigeration system via a pipeline. The cryogenic He gas refrigeration system includes a cryogenic pump, a He gas storage tank, a high-pressure compressor, a heat exchanger, and a throttling valve. The particle suppression module includes a cryogenic water vapor trap and an anti-particle backflow structure; the cryogenic water vapor trap and the worm gear molecular pump are connected in series on the right side of the reaction chamber, and an ICP plasma source is set at the top of the reaction chamber. The temperature closed-loop control system includes platinum resistance temperature sensors. Six platinum resistance temperature sensors are set at the center, edge, and four equal division points of the metal substrate. The measurement accuracy is ±0.1℃, the sampling frequency is 10Hz, and the temperature data of the ESC cryogenic chuck module is acquired in real time. The platinum resistance temperature sensors form a closed loop with the PID controller and the cryogenic pump. The ESC cryogenic chuck module includes an ESC cryogenic chuck, which consists of a metal substrate, a cryogenic thermal conductive layer, a dielectric layer, and a SiC bump array from bottom to top. The metal substrate has a built-in He gas microchannel, and the platinum resistance temperature sensor is embedded between the cryogenic thermal conductive layer and the dielectric layer. The probe contacts the vicinity of the He gas microchannel to ensure accurate temperature measurement. The cryogenic pump has a cylindrical structure and is equipped with a piston motor, cylinder, insulation layer, and speed sensor that work together. He gas enters from the inlet and is compressed and expanded by the piston for cooling. The insulation layer wraps around the cylinder to reduce cooling loss. The speed sensor monitors the piston motor speed in real time and feeds it back to the PID controller.

[0006] Preferably, the He gas is compressed to 10-15 MPa by a high-pressure compressor, pre-cooled by a heat exchanger, and then enters a cryogenic pump. The piston motor in the cryogenic pump drives the piston to reciprocate, and the He gas undergoes deep adiabatic compression and expansion cycle, achieving refrigeration by utilizing the Joule-Thomson effect.

[0007] Preferably, the piston motor speed can be steplessly adjusted within the range of 500-3000 rpm, and the speed is linearly positively correlated with the cooling capacity. For every 500 rpm increase in speed, the cooling capacity increases by 2 kW, and the output cooling capacity is 5-18 kW.

[0008] Preferably, the metal substrate is made of oxygen-free copper and has built-in He gas microchannels with a diameter of 0.5 mm and a spacing of 5 mm, which are directly connected to the cryogenic pump refrigeration circuit.

[0009] Preferably, the low-temperature thermally conductive layer is made of AlN ceramic with a thermal conductivity ≥170W / m・K and a thickness of 0.2mm; the dielectric layer is made of Y2O3-doped Al2O3 composite ceramic with a thickness of 0.3mm and a dielectric strength ≥20kV / mm; the SiC bump array is made of high thermal conductivity SiC material with a height of 10μm and a density of 500 bumps / cm².

[0010] Preferably, the integrated JR force adsorption unit achieves an adsorption force of ≥120gf / cm² at a low temperature of -100℃ using a DC voltage of 50-150V.

[0011] Preferably, the controller based on the PID algorithm receives data from the platinum resistance temperature sensor and compares it with the target temperature of -100°C, and outputs a speed adjustment command to the cryogenic pump.

[0012] Preferably, when the measured temperature is >-99℃ and 1℃ higher than the target value: the controller commands the piston motor speed to increase by 200-500 rpm; When the measured temperature is < -101℃, which is 1℃ lower than the target value: the controller commands the piston motor speed to decrease by 200-500 rpm; When the measured temperature is within the range of -101℃ to -99℃: maintain the current rotation speed; The total response time from temperature fluctuation to completion of cooling capacity adjustment is <0.8s, and it is compatible with ALE cycle cycles of 1-5s.

[0013] Preferably, the low-temperature water vapor trap is connected in series between the vacuum system and the reaction chamber, and uses He gas of the same origin as ESC for cooling to maintain the inner wall temperature of the low-temperature water vapor trap at -120°C, condensing water vapor in the chamber and reducing the partial pressure of H2O.

[0014] Preferably, the anti-particle backflow structure has a baffle plate at the inlet of the turbomolecular pump to optimize the airflow direction and reduce the rebound and backflow of AlF3 particles, which, together with the cryogenic water vapor trap, achieves dual suppression of particles.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, the extremely low temperature stability meets the standard: through He gas adiabatic compression, expansion cooling and closed-loop control, the ESC low temperature chuck can stably maintain -100℃±1℃, meeting the low temperature etching requirements of advanced processes. 2. In this invention, the temperature control accuracy and responsiveness are excellent: the piston motor speed is infinitely adjustable and the 10Hz high-frequency sampling results in a dynamic response time of <0.8s, which can offset the temperature fluctuations caused by the high energy load of the plasma. 3. In this invention, the defect density is significantly reduced: the low-temperature water vapor trap and the anti-backflow structure reduce the water vapor partial pressure inside the cavity to 1×10⁻⁶. -7 Below Pa, the number of particles is reduced by more than 60%, and the defect density is ≤0.05psi; In summary, the system of this invention has strong compatibility, the ESC dielectric layer is suitable for low-temperature environments and has no risk of embrittlement and breakdown, and the cooling system can output a cooling capacity of 5-18kW, adapting to the heat load requirements of different processes such as 3D NAND and MRAM. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Numbered in the diagram: 1. Reaction chamber; 2. ESC cryogenic chuck; 3. Cryogenic pump; 4. He gas storage tank; 5. High-pressure compressor; 6. Heat exchanger; 7. Throttling valve; 8. Wafer; 9. PID controller; 10. Cryogenic water vapor trap; 11. Turbomolecular pump; 12. ICP plasma source; Figure 2 This is a cross-sectional view of the internal structure of the cryogenic pump of the present invention; Numbered in the diagram: 31. Piston motor; 32. Cylinder; 33. He gas inlet; 34. He gas outlet; 35. Insulation layer; 36. Speed ​​sensor; Figure 3 This is a schematic cross-sectional view of the ESC cryogenic chuck of the present invention; In the figure, the following numbers are used: 21. Metal substrate; 22. He gas microchannel; 23. Low-temperature thermally conductive layer; 24. Dielectric layer; 25. SiC bump array; 26. Platinum resistance temperature sensor. Figure 4 This is a flowchart of the temperature closed-loop control of the present invention; The steps in the diagram are: ① Temperature acquisition (sensor sampling at 10Hz), ② Data comparison (with the target value of -100℃), ③ PID calculation (output speed adjustment command), ④ Motor speed adjustment (cooling capacity change), ⑤ Cooling capacity transfer to ESC, ⑥ Temperature feedback (closed loop). Figure 4 Explanation: The logic flow is represented by block diagrams and arrows, and the core parameters of each step (sampling frequency, adjustment range, response time) are labeled to clearly demonstrate the closed-loop control mechanism. Figure 5 This is a temperature control curve diagram of the present invention; The coordinates in the figure are: the horizontal axis represents time (s), the vertical axis represents the ESC low-temperature chuck temperature (°C), curve 1 represents the temperature change in Example 1, and curve 2 represents the temperature change in Example 2. Figure 5 Note: The curves show that the temperature drops rapidly during the start-up phase, fluctuates within ≤±1℃ during the stable phase, and recovers quickly under plasma thermal load impact. Example 2 shows even smaller fluctuations, demonstrating the advantages of the dual-loop system. Figure 6 These are comparative structural diagrams of two embodiments of the present invention; Left side of the figure (Example 2): Single refrigeration circuit, 6 sensors, single-layer water vapor trap; Right side of the figure (Example 3): Dual cooling circuit, 8 sensors, double-layer water vapor trap; Figure 6 Note: The core structural differences between the two embodiments are shown in a column comparison format, highlighting the different designs of key components, and intuitively demonstrating the optimization direction for adapting to different processes. Detailed Implementation

[0017] 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.

[0018] Example 1: This example provides a -100℃ low-temperature ALE etching apparatus based on He gas refrigeration closed-loop control. See [link to example]. Figures 1 to 6 Specifically, it includes reaction chamber 1, He gas cryogenic refrigeration system, ESC cryogenic chuck module, temperature closed-loop control system and particle suppression module; The left side of the reaction chamber 1 is connected to the He gas cryogenic refrigeration system via a pipeline. The He gas cryogenic refrigeration system includes a cryogenic pump 3, a He gas storage tank 4, a high-pressure compressor 5, a heat exchanger 6, and a throttling valve 7. The particle suppression module includes a cryogenic water vapor trap 10 and a particle backflow prevention structure; the cryogenic water vapor trap 10 and the worm gear molecular pump 11 are connected in series on the right side of the reaction chamber 1, and an ICP plasma source 12 is provided on the top of the reaction chamber 1. The temperature closed-loop control system includes platinum resistance temperature sensors 26. A total of 6 platinum resistance temperature sensors 26 are set at the center, edge and four equal division points of the metal substrate 21. The measurement accuracy is ±0.1℃ and the sampling frequency is 10Hz. The temperature data of the ESC cryogenic chuck module is collected in real time. The platinum resistance temperature sensors 26 form a closed loop with the PID controller 9 and the cryogenic pump 3. The ESC cryogenic chuck module includes an ESC cryogenic chuck 2. From bottom to top, the ESC cryogenic chuck 2 consists of a metal substrate 21, a cryogenic thermally conductive layer 23, a dielectric layer 24, and a SiC bump array 25. The metal substrate 21 has a built-in He gas microchannel 22. The platinum resistance temperature sensor 26 is embedded between the cryogenic thermally conductive layer 23 and the dielectric layer 24. The probe contacts the vicinity of the He gas microchannel 22 to ensure accurate temperature measurement. The cryogenic pump 3 has a cylindrical structure and is equipped with a piston motor 31, a cylinder 32, an insulation layer 35, and a speed sensor 36 that work together. He gas enters from the inlet and is compressed and expanded by the piston for cooling. The insulation layer 35 wraps around the cylinder 32 to reduce cooling loss. The speed sensor 36 monitors the speed of the piston motor 31 in real time and feeds it back to the PID controller 9.

[0019] In the specific implementation process, such as Figure 2 As shown, He gas is compressed to 10-15 MPa by high-pressure compressor 5, pre-cooled by heat exchanger 6 and then enters cryogenic pump 3. The piston motor in cryogenic pump 3 drives the piston to reciprocate, and He gas undergoes deep adiabatic compression and expansion cycle, using the Joule-Thomson effect to achieve refrigeration. The piston motor speed can be steplessly adjusted within the range of 500-3000rpm. The speed is linearly positively correlated with the cooling capacity. For every 500rpm increase in speed, the cooling capacity increases by 2kW, and the output cooling capacity is 5-18kW to meet the heat load requirements of different processes.

[0020] In the specific implementation process, such as Figure 3 As shown, the metal substrate 21 is made of oxygen-free copper and has a built-in He gas microchannel 22 with a diameter of 0.5 mm and a spacing of 5 mm, which is directly connected to the refrigeration circuit of the cryogenic pump 3. The low-temperature thermal conductive layer 23 is made of AlN ceramic with a thermal conductivity ≥170W / m・K and a thickness of 0.2mm, ensuring uniform transfer of cooling capacity; The dielectric layer 24 is made of Y2O3-doped Al2O3 composite ceramic with a thickness of 0.3 mm and a dielectric strength of ≥20 kV / mm, which is suitable for insulation requirements in low-temperature environments. The SiC bump array 25 is made of high thermal conductivity SiC material, with a height of 10μm and a density of 500 bumps / cm², which reduces the contact thermal resistance between wafer 8 and ESC low temperature chuck 2. The integrated JR force adsorption unit achieves an adsorption force of ≥120gf / cm² at a low temperature of -100℃ using a DC voltage of 50-150V, preventing wafer 8 from falling off.

[0021] In the specific implementation process, the controller based on the PID algorithm receives data from the platinum resistance temperature sensor 26 and compares it with the target temperature of -100℃, and outputs a speed adjustment command to the cryogenic pump 3. When the measured temperature is >-99℃ and 1℃ higher than the target value: the controller instructs the piston motor speed to increase by 200-500 rpm to increase the cooling capacity and cool down quickly; When the measured temperature is < -101℃, which is 1℃ lower than the target value: the controller instructs the piston motor speed to decrease by 200-500 rpm to reduce the cooling capacity and avoid overcooling; When the measured temperature is within the range of -101℃ to -99℃: maintain the current rotation speed to ensure temperature stability; The total response time from temperature fluctuation to completion of cooling capacity adjustment is <0.8s, and it is compatible with ALE cycle cycles of 1-5s.

[0022] In the specific implementation process, the low-temperature water vapor trap 10 is connected in series between the vacuum system and the reaction chamber 1. It uses He gas, which is the same as ESC, for refrigeration to maintain the inner wall temperature of the low-temperature water vapor trap 10 at -120℃, condensing water vapor in the chamber and reducing the partial pressure of H2O. The anti-particle backflow structure has a baffle plate at the inlet of the turbomolecular pump 11 to optimize the airflow direction and reduce the rebound and backflow of AlF3 particles. Together with the cryogenic water vapor trap 10, it achieves dual suppression of particles.

[0023] Example 2: Based on Example 1, this example is a single-loop He gas refrigeration cryogenic ALE device (adapted to 3D NAND process). The device structure and assembly are as follows: Refrigeration circuit setup: He gas storage tank 4, high-pressure compressor 5 (outlet pressure 15MPa), heat exchanger 6 (pre-cooled to -20℃), cryogenic pump 3 (piston motor rated speed 2500rpm), He gas microchannel 22, throttle valve 7, return to cryogenic pump 3, forming a closed loop; ESC Installation: Fix the low-temperature compatible ESC chuck 2 to the bottom of the reaction chamber 1, adjust the levelness error to <0.01mm, and embed 6 PT1000 platinum resistance temperature sensors 26 evenly under the dielectric layer of the ESC chuck 2 and connect them to the PID controller 9. Particle suppression module integration: A cryogenic water vapor trap 10 is connected in series between the turbomolecular pump 11 and the reaction chamber 1. The refrigeration pipeline of the cryogenic water vapor trap 10 is connected in parallel with the cryogenic pump 3 to maintain the inner wall temperature at -120℃. Control system debugging: Set the target temperature to -100℃, and set the PID controller 9 proportional coefficient Kp=2.5, integral coefficient Ki=0.8, and derivative coefficient Kd=0.3 to ensure stable closed-loop response.

[0024] Process implementation steps: Wafer 8 loading: The robotic arm transfers the 300mm3 DNAND wafer 8 to the ESC low-temperature chuck 2, and the JR force adsorption unit applies a 120V DC voltage, with an adsorption force detection value of 130gf / cm². Refrigeration start-up: Start the cryogenic pump, the piston motor starts at an initial speed of 1800 rpm, He gas circulates in the circuit for cooling, and the temperature of ESC cryogenic chuck 2 begins to drop; Closed-loop temperature control: The platinum resistance temperature sensor 26 provides real-time feedback data. When the temperature drops to -95℃, the PID controller 9 gradually increases the speed to 2300rpm, and stabilizes at -100℃ after 15s. Plasma excitation: A CF4 / O2 mixed gas (flow ratio 5:1) is introduced, and the ICP source outputs 300W power to excite the plasma. During the process, due to the plasma heat load (12kW), the temperature of the ESC cryogenic chuck 2 rises to -99.2℃, and the PID controller 9 immediately commands the speed to increase to 2400rpm, and then drops back to -100℃ within 0.6s. ALE cyclic etching: Execute a "1.5s adsorption - 2.5s etching" cycle for a total of 30 cycles to complete the etching of a 20nm thickness; Wafer 8 unloading: After etching is completed, the piston motor speed drops to 800 rpm, the temperature of ESC cryogenic chuck 2 slowly rises to -50℃, a -80V reverse pulse is applied to neutralize the residual charge, and the robotic arm unloads wafer 8.

[0025] Example 3: Based on Example 1, this example is a dual-loop He gas refrigeration low-temperature ALE equipment (adapted to MRAM process). Equipment structure differences: It adopts a dual-loop design of "main cooling loop and auxiliary temperature control loop": the main loop is responsible for lowering the temperature of ESC cryogenic chuck 2 to -100℃, and the auxiliary loop, independent cryogenic pump, piston motor speed range of 300-1500rpm, is responsible for compensating for local temperature differences. The ESC cryogenic chuck 2 features eight platinum resistance temperature sensors, including two edge-focused monitoring points, to accommodate the lower heat load (2kW) and higher temperature uniformity requirements of the MRAM process. The cryogenic water vapor trap 10 employs a double-layer condensation structure, with an inner layer temperature of -130°C, further reducing the water vapor partial pressure to 5×10⁻⁶. -8 Pa.

[0026] Process characteristics: The target temperature is stabilized at -100℃±0.8℃, and the temperature uniformity of the entire wafer 8 is <0.5℃; the auxiliary circuit compensates for edge heat loss by adjusting the local He gas flow rate, avoiding the problem of excessive edge temperature; the particle number is further reduced by 25% compared with Example 1, and the defect density is ≤0.03psi, which is suitable for the stringent cleanliness requirements of MRAM devices.

[0027] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A -100℃ low-temperature ALE etching apparatus based on He gas refrigeration closed-loop control, comprising a reaction chamber (1), a He gas low-temperature refrigeration system, an ESC low-temperature chuck module, a temperature closed-loop control system, and a particle suppression module, characterized in that: The left side of the reaction chamber (1) is connected to the He gas cryogenic refrigeration system through a pipeline. The He gas cryogenic refrigeration system includes a cryogenic pump (3), a He gas storage tank (4), a high-pressure compressor (5), a heat exchanger (6), and a throttle valve (7). The particle suppression module includes a cryogenic water vapor trap (10) and a particle backflow prevention structure; the cryogenic water vapor trap (10) and the worm gear molecular pump (11) are connected in series on the right side of the reaction chamber (1), and an ICP plasma source (12) is provided on the top of the reaction chamber (1). The temperature closed-loop control system includes a platinum resistance temperature sensor (26). A total of 6 platinum resistance temperature sensors (26) are set at the center, edge and four equal division points of the metal substrate (21). The measurement accuracy is ±0.1℃ and the sampling frequency is 10Hz. The temperature data of the ESC low temperature chuck module is collected in real time. Among them, the platinum resistance temperature sensor (26) forms a closed loop with the PID controller (9) and the low temperature pump (3). The ESC low-temperature chuck module includes an ESC low-temperature chuck (2). From bottom to top, the ESC low-temperature chuck (2) consists of a metal substrate (21), a low-temperature thermally conductive layer (23), a dielectric layer (24), and a SiC bump array (25). The metal substrate (21) has a built-in He gas microchannel (22). The platinum resistance temperature sensor (26) is embedded between the low-temperature thermally conductive layer (23) and the dielectric layer (24). The probe contacts the vicinity of the He gas microchannel (22) to ensure accurate temperature measurement. The cryogenic pump (3) has a cylindrical structure and is equipped with a piston motor (31), a cylinder (32), an insulation layer (35), and a speed sensor (36) that work together. He gas enters from the inlet and is compressed and expanded by the piston for cooling. The insulation layer (35) wraps around the cylinder (32) to reduce cooling loss. The speed sensor (36) monitors the speed of the piston motor (31) in real time and feeds it back to the PID controller (9). He gas is compressed to 10-15 MPa by a high-pressure compressor (5), and after being pre-cooled by a heat exchanger (6), it enters a cryogenic pump (3). The piston motor inside the cryogenic pump (3) drives the piston to reciprocate, and the He gas undergoes deep adiabatic compression and expansion cycle, using the Joule-Thomson effect to achieve refrigeration. The piston motor speed can be steplessly adjusted within the range of 500-3000rpm. The speed is linearly positively correlated with the cooling capacity. For every 500rpm increase in speed, the cooling capacity increases by 2kW, and the output cooling capacity is 5-18kW. The metal substrate (21) is made of oxygen-free copper and has a built-in He gas microchannel (22) with a diameter of 0.5mm and a spacing of 5mm, which is directly connected to the refrigeration circuit of the cryogenic pump (3). The low-temperature thermal conductive layer (23) is made of AlN ceramic with a thermal conductivity ≥170W / m・K and a thickness of 0.2mm; the dielectric layer (24) is made of Y2O3-doped Al2O3 composite ceramic with a thickness of 0.3mm and a dielectric strength ≥20kV / mm; the SiC bump array (25) is made of high thermal conductivity SiC material with a height of 10μm and a density of 500 bumps / cm²; the integrated JR force adsorption unit achieves an adsorption force ≥120gf / cm² at a low temperature of -100℃ through a DC voltage of 50-150V.

2. The -100℃ low-temperature ALE etching equipment based on He gas refrigeration closed-loop control according to claim 1, characterized in that: The controller based on the PID algorithm receives data from the platinum resistance temperature sensor (26) and compares it with the target temperature of -100℃, and outputs a speed adjustment command to the cryogenic pump (3).

3. The -100℃ low-temperature ALE etching equipment based on He gas refrigeration closed-loop control according to claim 1, characterized in that: When the measured temperature is >-99℃ and 1℃ higher than the target value: the controller commands the piston motor speed to increase by 200-500 rpm; When the measured temperature is < -101℃, which is 1℃ lower than the target value: the controller commands the piston motor speed to decrease by 200-500 rpm; When the measured temperature is within the range of -101℃ to -99℃: maintain the current rotation speed; The total response time from temperature fluctuation to completion of cooling capacity adjustment is <0.8s, and it is compatible with ALE cycle cycles of 1-5s.

4. The -100℃ low-temperature ALE etching equipment based on He gas refrigeration closed-loop control according to claim 1, characterized in that: The low-temperature water vapor trap (10) is connected in series between the vacuum system and the reaction chamber (1). It uses He gas, which is the same as ESC, for cooling, to maintain the inner wall temperature of the low-temperature water vapor trap (10) at -120°C, condense water vapor in the chamber, and reduce the partial pressure of H2O.

5. The -100℃ low-temperature ALE etching equipment based on He gas refrigeration closed-loop control according to claim 4, characterized in that: The anti-particle backflow structure has a guide plate at the inlet of the turbomolecular pump (11) to optimize the airflow direction and reduce the rebound and backflow of AlF3 particles. It works in conjunction with the low-temperature water vapor trap (10) to achieve dual suppression of particles.

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