Level adjustment device

Abstract

This disclosure provides a horizontal adjustment device, comprising: a chamber; a heater including a body and a base, the base being located outside the chamber, one end of the body being located inside the chamber for supporting a wafer, and the other end of the body being connected to the base; a height adjustment device coupled to the chamber and the heater for changing the horizontal state of the wafer; a controller electrically coupled to the height adjustment device for controlling the height adjustment device, reading the state of the height adjustment device, and sending a system state, the system state including the horizontal state of the wafer and the state of the height adjustment device; and a central control system for receiving the system state from the controller and issuing control commands to the controller according to the system state to control the height adjustment device for changing the horizontal state of the wafer.

Description

[Technical Field]

[0001] The present invention relates to a horizontal adjustment device, and more particularly to a horizontal adjustment device for semiconductor manufacturing processes. [Previous Technology]

[0002] In the semiconductor manufacturing process, different products or processes have many different process requirements. To meet these requirements, semiconductor production equipment needs to be adjusted to suitable conditions. In the past, equipment adjustments relied on manual methods. Although this could mostly meet the process requirements, the techniques for adjusting the equipment varied from person to person, and experience was lost because it could not be passed on. Therefore, there is a need for automated processes to adjust the machines more efficiently. [Summary of the Invention]

[0003] The present invention provides a horizontal adjustment device, comprising: a chamber; a heater including a body and a base, the base being located outside the chamber, one end of the body being located inside the chamber for supporting a wafer, and the other end of the body being connected to the base; a height adjustment device coupled to the chamber and the heater for changing the horizontal state of the wafer; a controller electrically coupled to the height adjustment device for controlling the height adjustment device, reading the state of the height adjustment device, and sending a system state, the system state including the horizontal state of the wafer and the state of the height adjustment device; and a central control system receiving the system state sent by the controller and issuing control commands to the controller according to the system state to control the height adjustment device for changing the horizontal state of the wafer.

[0004] In one embodiment of the present invention, the height adjustment device includes: a telescopic spring connected to the bottom surface of the chamber and the top surface of the base of the heater; a plurality of control feet, each of the plurality of control feet including: a motor, a connector, and a vertically upward extending screw, wherein the motor is coupled to the bottom end of the screw via the connector to drive the screw to rotate, and the top end of the screw contacts the bottom surface of the chamber; a platform, wherein the telescopic spring and the plurality of control feet are all fixed to the platform, wherein the controller issues the control command to the height adjustment device to control the motors of the plurality of control feet to change the distance between the bottom of the chamber and the platform of each screw.

[0005] In one embodiment of the present invention, the number of the plurality of control feet is greater than or equal to three.

[0006] In one embodiment of the present invention, the motor is a stepper motor.

[0007] In one embodiment of the present invention, each of the plurality of control feet further includes: a displacement sensor for measuring the distance between the screw and the platform at the bottom of the chamber, wherein the system state includes the distance between the screw of each of the plurality of control feet and the platform at the bottom of the chamber.

[0008] In one embodiment of the present invention, the controller and the central control system are connected via a wired network or a wireless network to transmit the system status and the control commands to each other.

[0009] In one embodiment of the present invention, the central control system determines whether to issue the control command to the controller based on whether the system state meets the judgment conditions.

[0010] In one embodiment of the present invention, the determination condition includes: if the uniformity of the thickness distribution of the wafer is greater than a threshold in the horizontal state, then the central control system issues the control command to the controller; if the uniformity is equal to or less than the threshold, then the central control system does not issue the control command to the controller, wherein the uniformity is the ratio of half the difference between the maximum value and the minimum value of the thickness distribution to the average value of the thickness distribution.

[0011] In one embodiment of the present invention, the leveling device further includes: an operating device, the operating device including a communication device, a display device, and an input device, wherein the communication device is communicatively connected to the central control system and the controller respectively, and is configured to receive the system status and the control command from the central control system, the display device is used to display the system status, and the input device is used to input an instruction to cause the communication device to issue or not issue the control command to the controller.

[0012] In one embodiment of the present invention, the system status is displayed in a table format on the display device.

[0013] In one embodiment of the present invention, the central control system obtains the expected system state after changing the height adjustment device in a simulated manner according to the system state and the control command, the communication device receives the expected system state from the central control system, and the display device uses it to display the expected system state.

[0014] In one embodiment of the present invention, the expected system state includes at least one of the estimated adjustment range of at least one of the plurality of control feet and / or the estimated uniformity of the estimated thickness distribution of the wafer.

[0015] Based on the above, by adjusting machines in a smart and automated manner, and by adjusting machines for customized programs, work efficiency can be greatly improved and human error reduced. The accumulated machine adjustment data can also build a big data database for the machines themselves, upgrading the machine adjustment process from one that could only be done through personal skills and experience to one that can be done in a smart and automated manner.

Implementation Method

[0017] FIG1 is a schematic diagram of a wafer processing apparatus according to an embodiment of the present invention. Please refer to FIG1. ​​In semiconductor manufacturing, wafers are transported to a wafer processing apparatus for processing. Without loss of generality, the wafer processing apparatus 100 includes a front-end module 110, a loading device 120, a wafer processing chamber 130, and a chamber module 140.

[0018] The front-end module 110 of the device is provided with a loading port 112, a robotic arm 114, and an aligner 116. The front-opening unified pod (FOUP) transfers the wafer and places it on the loading port 112. The robotic arm 114 uses a vacuum adsorption device or an electrostatic chuck to transport the wafer on the loading port 112 to the aligner 116, for example, wafer W1 on the aligner 116.

[0019] The alignment device 116 includes a rotating stage and a sensor. The sensor detects the wafer W1 placed on the rotating stage and detects the notch WN on the wafer W1. Using information such as the position of the notch WN, the rotating stage is used to orient the wafer W1, i.e., rotate it to a specified direction to ensure the positioning of the wafer. In addition, a conventional thickness measurement device is used to measure the thickness of the wafer W1 to determine the thickness distribution on the surface of the wafer W1.

[0020] The loading device 120 is located downstream of the front-end module 110. The loading device 120 is a vacuum chamber used to load or unload wafers before or after wafer processing. The front-end module 110 and the loading device 120 have a vacuum gate to isolate the loading device 120 from a vacuum state. The loading device 120 includes a loading locking platform 122 for carrying wafers, such as wafer W2. The loading locking platform 122 is located within the movement range of the robotic arm 114, allowing the robotic arm 114 to move the wafer between the loading port 112 and the loading locking platform 122. In this embodiment, the loading device 120 has two loading locking platforms 122 for carrying two wafers.

[0021] The wafer processing chamber 130 is connected to the loading device 120. The wafer processing chamber 130 is also connected to multiple chamber modules 140. In this embodiment, the wafer processing chamber 130 is connected to three chamber modules 140. In other embodiments, the number of wafer processing chambers 130 may be one, two, or other suitable numbers, and this disclosure is not limited thereto. As shown in FIG1, each chamber module 140 has two wafer processing platforms 142. In other embodiments, the wafer processing platform 142 may be one, and this disclosure is not limited thereto.

[0022] The wafer W3 placed on the wafer processing platform 142 can be processed in the chamber module 140, such as by coating or etching.

[0023] The wafer processing chamber 130 has a robotic arm 132 for transporting wafers back and forth between the loading and locking platform 122 and the wafer processing platform 142.

[0024] When the wafer is sent to the wafer processing platform 142, the wafer surface is uneven in thickness due to the processing. Therefore, when the wafer is placed on the wafer processing platform 142, the wafer processing platform must be leveled to ensure that the wafer surface is flat enough to facilitate subsequent processing, such as coating or etching.

[0025] To ensure the level of the wafer, the leveling device described in this disclosure can be used to adjust the level of the wafer.

[0026] FIG2A is a front view of a leveling device according to an embodiment of the present invention. FIG2B is a side view of a leveling device according to an embodiment of the present invention. FIG2C is a schematic diagram of a portion of a leveling device according to an embodiment of the present invention.

[0027] Please refer to Figures 2A, 2B and 2C. The leveling device 200 includes: a chamber 210, a heater 220, a height adjustment device 230, a controller 300 and a central control system 320.

[0028] The cavity 210 is an embodiment of the cavity module 140 in FIG1, used to process the wafer W located in the cavity 210.

[0029] The heater 220 includes a body 222 and a base 224. The base 224 is located outside the chamber 210. One end 222A of the body 222 is located inside the chamber 210 to support the wafer W, and the other end 222B of the body 222 is connected to the base 224. When the wafer W is placed on the body 222, since the surface of the wafer W has a thickness distribution, the heater 220 must be horizontally adjusted so that the uniformity of the thickness distribution on the wafer surface meets the required limits.

[0030] The horizontal adjustment device 200 further includes a height adjustment device 230. The height adjustment device 230 is coupled to the chamber 210 and the heater 220 to change the horizontal state of the wafer W.

[0031] As shown in Figures 2A and 2B, the height adjustment device 230 includes a telescopic spring 232, multiple control feet 233, and a platform 242.

[0032] The telescopic spring 232 is connected to the bottom surface 210B of the chamber 210 and the top surface 224T of the base 224 of the heater 220. Specifically, the body 222 of the heater 220 is located inside the telescopic spring 232 and is covered by the telescopic spring 232. Since the telescopic spring 232 is elastic and is connected to the bottom surface 210B of the chamber 210 and the top surface 224T of the base 224 of the heater 220, the position of the heater 220 can be changed by changing the shape of the telescopic spring 232, thereby changing the horizontal state of the wafer W located above the body 222 of the heater 220.

[0033] Each of the plurality of control feet 233 includes: a motor 234, a connector 236, and a vertically upward extending screw 238. The motor 234 is coupled to the bottom end of the screw 238 via the connector 236. The top end of the screw 238 contacts the bottom surface 210B of the chamber 210. The distance d between the bottom 210B of the chamber 210 and the top surface 242T of the platform 242 can be increased or decreased by the motor 234 driving the screw 238 to rotate.

[0034] In some embodiments, the motor 234 is a stepper motor to precisely control the rotation of the motor, thereby driving the screw to rotate by a small angle to adjust the level of the wafer. In addition, the motor 234 is connected to the control console 300 and performs specified rotations according to control commands issued by the control console 300, including the rotation direction and rotation angle.

[0035] The height adjustment device 230 further includes a platform 242. As shown in Figures 2A and 2B, the telescopic spring 232 and multiple control feet 233 are fixed to the platform 242. Specifically, the telescopic spring 232 passes through and is fixed to the platform 242, so the shape and length of the telescopic spring 232 can be changed by controlling the height of the platform 242. On the other hand, the screw 238 of the control feet 233 passes through the through hole on the platform 242 and is fixed to the platform 242. Specifically, the through hole of the platform 242 and the screw 238 have threads, so the platform 242 can engage with the screw 238 through these threads. When the screw 238 is rotated by the rotation of the motor 234, the horizontal position of the platform 242 can be changed by the threads in the corresponding through hole on the platform 242. Since the platform 242 is connected to the telescopic spring 232, the telescopic spring 232 can be driven at the same time, and linked with the heater 220, thereby adjusting the horizontal state of the wafer W.

[0036] In this embodiment, the number of control feet is three. In other embodiments, the number of control feet may be greater than three. Specifically, when the number of control feet is three, the top end of the screw 238 of each control foot can be stably in contact with the bottom surface 210B of the chamber 210.

[0037] On the other hand, when there are three control pins, the wafer level can be adjusted by fixing one of the three control pins and adjusting the other two of the three control pins, thereby simplifying the steps of adjusting the wafer level.

[0038] Each of the control feet 232 further includes a displacement sensor 240 for measuring the distance d between the screw 238 at the bottom 210B of the chamber 210 and the platform 242. System status includes the distance between the screw 238 of each of the plurality of control feet at the bottom of the chamber 210 and the platform 242.

[0039] By using displacement sensor 240 to measure the distance between screw 238 at the bottom 210B of chamber 210 and platform 242 in real time, the distance between screw 238 at the bottom 210B of chamber 210 and platform 242 can be known in real time when the height of the corresponding control foot 233 is adjusted by screw.

[0040] In some embodiments, the displacement sensor 240 may be used for ranging by ultrasound, laser or other similar means, but this disclosure is not limited thereto.

[0041] The leveling device 200 further includes a controller 300. The controller 300 is electrically coupled to the height adjustment device 230 for controlling the height adjustment device 230, reading the status of the height adjustment device 230, and sending system status. The system status includes the leveling status of the wafer W and the status of the height adjustment device 230.

[0042] In addition, the controller 300 can issue control commands to the height adjustment device 230 to control the motor 234 of each control foot 233 respectively. By rotating the motor 234 to drive the screw 238, the controller 300 can change the distance d between the bottom 210B of the chamber 210 and the platform 242 of each screw 238 to adjust the horizontal state of the wafer W.

[0043] As shown in FIG2C, the leveling device 200 further includes a central control system 320, which receives the system status issued by the controller 300 and issues control commands to the controller 300 according to the system status to control the height adjustment device 230 to change the leveling state of the wafer W. In some embodiments, the central control system 320 may be a cloud system, a remote server, or a computer, and this disclosure is not limited thereto.

[0044] By receiving the system status sent by the controller 300 through the central control system 320, the central control system can store the system status of the leveling device 200 and analyze it within the central control system 320 to determine the adjustment method of the screw 238 in each control foot 233, including rotating in a clockwise or counterclockwise direction and the degree of rotation, so as to change the distance d between the bottom 210B of the chamber 210 and the platform 242 of each screw 238, so as to adjust the leveling state of the wafer W.

[0045] Therefore, the central control system 320 can issue control commands to the controller 300 based on the system status of the received level adjustment device 200. After receiving the control command, the controller 300 issues a control command to the height control system to change the distance d between each screw 238 at the bottom 210B of the chamber 210 and the platform 242, so as to adjust the level state of the wafer W.

[0046] The controller 300 and the central control system 320 are connected via a wired network or a wireless network to transmit system status and control commands to each other. In some embodiments, the wireless network includes Bluetooth, WiFi, or other wireless transmission methods, and this disclosure is not limited thereto.

[0047] As shown in Figure 2C, the leveling device 200 further includes an operating device 340. The operating device 340 includes a communication device 342, a display device 344, and an input device 346. The communication device 342 is communicatively connected to the central control system 320 and the controller 300, respectively, and is configured to receive system status and control commands from the central control system 320. The display device 344 is used to display the system status, and the input device 346 is used to input an instruction so that the communication device 342 may or may not issue control commands to the controller 300.

[0048] Therefore, the system status and control commands issued by the central control system 320 can be sent to the operating device 340 first, and the user can check the system status and control commands first, and then decide whether to send the control commands to the controller 300 for subsequent operations.

[0049] In some embodiments, the system status is displayed in a table format on the operating device 340.

[0050] In some embodiments, the operating device 340 may be a desktop computer, a laptop computer, a tablet computer, or a smartphone. The communication device 342 may be a wireless network device, a WiFi device, a Bluetooth device, or other devices with similar functions. The display device 344 may be a screen, such as the screen of a mobile phone, tablet computer, or desktop computer. The input device 346 may be a touch screen, a keyboard, a mouse, or other input devices.

[0051] Therefore, as shown in FIG2C, the central control system 320 can directly issue control commands to the console 300, or it can issue commands to the console through the operating device 340. In particular, when the central control system 320 directly issues control commands to the console 300, the central control system 320 automatically performs the operation. On the other hand, when the central control system 320 issues commands to the console through the operating device 340, the operator can view and confirm the control commands through the operating device 340 to determine whether the control commands need to continue to be executed.

[0052] FIG3 is a schematic diagram of a controller according to an embodiment of the present invention. Please refer to FIG3. The controller 300 includes a power supply 302, an input / output module 304, a programmable logic controller (PLC) 306, a driver module 308, a sensor module 310, a wireless network module 312, a power plug 314, a motor adapter 316, and a sensor adapter 318.

[0053] Specifically, the power supply 302 provides power to various components within the controller 300. The input / output module 304 receives the horizontal state of the wafer W and the state of the height adjustment device 230. The input / output module 304 outputs the received information to the programmable logic controller 306. The programmable logic controller 306 integrates the received information into a system state and outputs it wirelessly via the wireless network module 312.

[0054] The driver module 308 is used to drive the motor of the height adjustment device 230, while the sensor module 310 is connected to the displacement sensor 240 to obtain displacement information.

[0055] Therefore, with the above structure, the controller 300 can be used to read the status of the height adjustment device 230 and send the system status.

[0056] Figure 4 is a schematic diagram of the wafer thickness distribution according to an embodiment of the present invention. Please refer to Figure 4. Uneven thickness is caused on the wafer surface during processing; therefore, thickness measurements are performed on the wafer surface to obtain the wafer thickness distribution shown in Figure 4. Taking Figure 4 as an example, the thickness distribution of this wafer is highest at the center and gradually decreases towards the wafer edge. Specifically, the film thickness distribution at the lower edge of the wafer is approximately 3900 nm, significantly lower than the film thickness in other areas.

[0057] Figure 4 also shows the statistics for the wafer film thickness distribution. For example, the average film thickness is 4144.4 nm; the three-standard deviation (3-σ) of the thickness distribution is 353.4 nm; the thickness range is 459.6 nm; and the uniformity is 5.5%. The thickness range is defined as the difference between the maximum and minimum film thicknesses, and the uniformity is defined as the ratio of half the thickness range to the average film thickness. A smaller thickness range indicates a smaller difference between the maximum and minimum film thicknesses, and a more uniform film thickness distribution. When the thickness range or uniformity is less than or equal to a threshold, the film thickness distribution meets the standard. When the thickness range or uniformity is greater than a threshold, the film thickness distribution does not meet the standard, and a leveling device is needed to adjust the wafer's level. In some embodiments, the threshold is 5% for uniformity, but different thresholds can be defined depending on actual needs, such as the film material or thickness. In this embodiment, the uniformity threshold is 5%, and the uniformity of the film thickness distribution is 5.5%, so a leveling device is needed to adjust the level of the wafer.

[0058] When the central control system 320 receives the system status sent by the controller 300, the central control system can store the system status of the leveling device 200 and analyze it in the central control system 320 to determine the adjustment method of the screw 238 in each control foot 233, including rotating in a clockwise or counterclockwise direction and the degree of rotation, so as to change the distance d between the bottom 210B of the chamber 210 and the platform 242 of each screw 238, so as to adjust the leveling state of the wafer W.

[0059] After the central control system 320 completes its analysis, it determines whether to issue a control command to the controller 300 based on whether the system state meets the judgment conditions. In this embodiment, the judgment conditions include: if the uniformity of the thickness distribution of wafer W is greater than a threshold in the horizontal state, the central control system 320 issues a control command to the controller 300; if the uniformity is equal to or less than the threshold, the central control system 320 does not issue a control command to the controller 300, wherein the uniformity is the ratio of half the difference between the maximum and minimum values ​​of the thickness distribution to the average value of the thickness distribution. However, in other embodiments, the judgment conditions may also be based on other system information, and this disclosure is not limited thereto.

[0060] When the central control system 320 determines that a control command needs to be issued to the controller 300, the central control system 320 obtains the expected system state after changing the height adjustment device 230 in a simulation manner based on the system state and the control command. The communication device 342 receives the expected system state from the central control system 320, and the display device 344 uses it to display the expected system state.

[0061] The expected system state includes at least one of the estimated adjustment range of at least one of the multiple control pins and / or the estimated uniformity of the estimated thickness distribution of the wafer W.

[0062] FIG5 is a schematic diagram of the system status according to an embodiment of the present invention. Please refer to FIG5. This system status is displayed in tabular form on the display device 344 of the operating device 340 so that the user can directly obtain the system status.

[0063] The system status has multiple items. Among them, the average THK (average thickness), highest point, lowest point, Range (thickness range), U% (uniformity), and Spec (threshold) are all system statuses sent from the controller 300 to the central control system 340. Map, LP position, estimated adjustment range #1, estimated adjustment range #3, estimated optimal Range, and estimated optimal U% are the expected system statuses obtained by the central control system 320 through simulation after changing the height adjustment device 230, and are displayed on the display device 344 of the operating device 340.

[0064] As shown in Figure 5, the control command will adjust the two control feet 233 (#1, #3). The system can further predict that the adjusted thickness range will be approximately 4139.7 nm, and the uniformity will decrease from 5.54% to below the threshold of 4.3%.

[0065] After the user confirms the expected system status through the display device 344 of the operating device 340, he / she can input a command through the input device 346 of the operating device 340, so that the operating device 340 sends the control command to the controller 300, so that the controller 300 executes the operation.

[0066] After the user confirms the expected system status through the display device 344 of the operating device 340, if the user believes that the result of the expected system status does not meet the requirements, the user can also input a command through the input device 346 of the operating device 340 so that the operating device 340 does not send the control command to the controller 300.

[0067] Figure 6 is a flowchart of a wafer leveling method according to an embodiment of the present invention. Please refer to Figure 6. The wafer leveling method S400 includes the following steps.

[0068] In step S402, when the chamber module 140 is about to restart the coating process, or when the film thickness measurement reveals an abnormality in the film deposited by the chamber module 140, a level adjustment process is initiated to confirm the status of the chamber module 140. Then, step S404 is executed.

[0069] In step S404, quality control measurements are performed on the wafer to obtain, for example, the wafer thickness distribution map shown in Figure 4. Then, step S406 is executed.

[0070] In step S406, statistical analysis is performed on the film thickness distribution map to obtain relevant parameters of the film thickness distribution, such as average THK (average thickness), highest point, lowest point, Range (thickness range), and U% (uniformity), and it is checked whether the relevant parameters meet the judgment conditions. If the judgment conditions are not met, for example, if the uniformity is greater than the threshold, then step S408 is executed. If the judgment conditions are met, for example, if the uniformity is less than the threshold, then step S414 is executed.

[0071] In step S408, the central control system 320 draws a film thickness distribution map. In some embodiments, the film thickness distribution map is shown in FIG4. Then, step S410 is executed.

[0072] In step S410, the central control system 320 calculates the adjustment method and magnitude of the height control system 230 based on the relevant parameters of the film thickness distribution obtained in step 406, such as average THK (average thickness), highest point, lowest point, Range (thickness range), U% (uniformity), and the film thickness distribution map obtained in step S408. Specifically, the central control system 320 calculates the adjustment method of the screw 238 in each control foot 233 of the height control system 230, including rotation in a clockwise or counterclockwise direction, the degree of rotation, and the distance by which the screw 238 extends or shortens. Then, step S412 is executed.

[0073] In step S412, the central control system 320 issues a control command to the controller 300. The controller 300, according to the control command, controls the motor 234 in the mounting bracket 233 to rotate accordingly, thereby adjusting the length of the screw 238 and changing the horizontal state of the wafer. Then, step S414 is executed.

[0074] In step S414, the system's horizontal state has been adjusted, so a new round of the process can continue.

[0075] In summary, the present invention, by adjusting machines in a smart and automated manner and by adjusting machines for specific programs, can significantly improve work efficiency and reduce human error. The accumulated machine adjustment data can also establish a big data database for the machines themselves, upgrading machine adjustments from something that could only be done through personal skills and experience to something that can be done in a smart and automated manner. [Simplified Explanation of the Diagram]

[0016] FIG1 is a schematic diagram of a wafer processing apparatus according to an embodiment of the present invention. FIG2A is a front view of a horizontal adjustment apparatus according to an embodiment of the present invention. FIG2B is a side view of a horizontal adjustment apparatus according to an embodiment of the present invention. FIG2C is a schematic diagram of a portion of a horizontal adjustment apparatus according to an embodiment of the present invention. FIG3 is a schematic diagram of a controller according to an embodiment of the present invention. FIG4 is a schematic diagram of wafer thickness distribution according to an embodiment of the present invention. FIG5 is a schematic diagram of system state according to an embodiment of the present invention. FIG6 is a flowchart of a wafer horizontal adjustment method according to an embodiment of the present invention.

Claims

1. A leveling device, comprising: One chamber; A heater includes a body and a base, the base being located outside the chamber, one end of the body being located inside the chamber for supporting a wafer, and the other end of the body being connected to the base; A height adjustment device, coupled to the chamber and the heater, is used to change the horizontal state of the wafer; a controller, electrically coupled to the height adjustment device, is used to control the height adjustment device, read the state of the height adjustment device, and send a system status, the system status including the horizontal state of the wafer and the state of the height adjustment device; a central control system receives the system status sent by the controller and issues control commands to the controller according to the system status to control the height adjustment device to change the horizontal state of the wafer.

2. The leveling device as claimed in claim 1, wherein the height adjusting device comprises: A telescopic spring is connected to the bottom surface of the chamber and the top surface of the base of the heater; A plurality of control feet, each of the plurality of control feet including: a motor, a connector, and a vertically upward extending screw, wherein the motor is coupled to the bottom end of the screw via the connector to drive the screw to rotate, and the top end of the screw contacts the bottom surface of the chamber; a platform, wherein the telescopic spring and the plurality of control feet are fixed to the platform, wherein the controller issues the control command to the height adjustment device to control the motors of the plurality of control feet to change the distance between the bottom of the chamber and the platform of each screw.

3. The leveling device as claimed in claim 2, wherein the number of the plurality of control feet is greater than or equal to three.

4. The leveling device as claimed in claim 2, wherein the motor is a stepper motor.

5. The leveling device as claimed in claim 2, wherein each of the plurality of control feet further comprises: A displacement sensor is used to measure the distance between the screw and the platform at the bottom of the chamber, wherein the system status includes the distance between the screw of each of the plurality of control feet and the platform at the bottom of the chamber.

6. The leveling device as claimed in claim 1, wherein the controller is communicatively connected to the central control system via a wired or wireless network to mutually transmit the system status and the control commands.

7. The leveling device as claimed in claim 1, wherein the central control system determines whether to issue the control command to the controller based on whether the system state meets the judgment conditions.

8. The leveling device as claimed in claim 7, wherein the determination condition includes: In the horizontal state, if the uniformity of the thickness distribution of the wafer is greater than a threshold, then the central control system issues the control command to the controller. If the uniformity is equal to or less than the threshold, the central control system will not issue the control command to the controller, wherein the uniformity is the ratio of half the difference between the maximum and minimum values ​​of the thickness distribution to the average value of the thickness distribution.

9. The leveling device as described in claim 1, further comprising: An operating device includes a communication device, a display device, and an input device. The communication device is communicatively connected to the central control system and the controller, respectively, and is configured to receive the system status and the control command from the central control system. The display device is used to display the system status, and the input device is used to input an instruction to cause the communication device to issue or not issue the control command to the controller.

10. The leveling device as claimed in claim 9, wherein the system status is displayed in a tabular manner on the display device.

11. The leveling device as claimed in claim 9, wherein the central control system obtains, in a simulated manner, the expected system state after changing the height adjustment device based on the system state and the control command, the communication device receives the expected system state from the central control system, and the display device is used to display the expected system state.

12. The leveling device as claimed in claim 11, wherein the expected system state includes at least one of the estimated adjustment range of at least one of the plurality of control feet and / or the estimated uniformity of the estimated thickness distribution of the wafer.

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