Error compensation system for a lithography machine

Abstract

The application relates to an error compensation system of a photoetching machine and relates to the technical field of photoetching machine error compensation, which comprises a bearing table, a mask plate and a processor arranged on the photoetching machine, the upper surface of the bearing table is provided with a plurality of wedge blocks and linear brakes which are spaced and symmetrically arranged in the circumferential direction, the linear brakes are fixedly connected with the bearing table, the wedge blocks are movably connected with the bearing table in the direction of approaching or moving away from the symmetric axis and can drive the wedge blocks to move, the upper surface of the wedge block is provided with an inclined surface, all the inclined surfaces of the wedge blocks jointly support a movable table, the upper surface of the bearing table is coaxially provided with a reference ring, the reference ring is located below the mask plate, a plurality of first capacitive sensors are symmetrically and spaced arranged on the reference ring in the circumferential direction, and the first capacitive sensors are used for detecting the distance from the mask plate. The application has the effect of guaranteeing the parallelism between the mask plate and the silicon wafer surface during overlay and improving the yield of chips.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithography machine error compensation, in particular to a lithography machine error compensation system. BACKGROUND

[0002] In the technical field of lithography machine, as a key link in integrated circuit manufacturing, lithography process plays a vital role in chip manufacturing. The lithography machine mainly transfers the fine pattern on the mask plate to the silicon wafer through ultraviolet exposure, thereby realizing the construction of chip circuit.

[0003] In the development process of lithography machine, to ensure the yield of chips, improving the alignment accuracy between the mask plate and the silicon wafer has always been a key problem. In the past, in order to ensure the parallelism of the mask plate and the silicon wafer surface during overlay, the conventional means is to use error compensation device, among which the combination of reference plate and small ball is more common. This combination mainly uses the reference plate to provide a relatively stable reference plane, and the small ball plays a role in buffering and fine tuning to some extent, so as to try to compensate for the error in the overlay process. However, with the continuous evolution of semiconductor technology, the requirement for overlay accuracy is becoming more and more demanding, and this traditional combination method gradually exposes its limitations. SUMMARY

[0004] In order to ensure the parallelism of the mask plate and the silicon wafer surface during overlay and improve the yield of chips, the present application provides a lithography machine error compensation system.

[0005] The lithography machine error compensation system provided by the present application adopts the following technical scheme:

[0006] A lithography machine error compensation system, comprising a bearing table, a mask plate and a processor provided on a lithography machine, the upper surface of the bearing table is provided with a plurality of wedge blocks and linear actuators which are spaced apart and symmetrically arranged in the circumferential direction, the linear actuators are fixedly connected with the bearing table, the wedge blocks are movably connected with the bearing table in the direction of approaching or moving away from the symmetric axis, the linear actuators correspond to the wedge blocks one by one and can drive the wedge blocks to move, the upper surface of the wedge block is obliquely provided with an inclined surface, all the inclined surfaces of the wedge blocks collectively support a movable table, and the lower edge of the movable table is in abutment with the inclined surface, the movable table is used for carrying a silicon wafer, the upper surface of the bearing table is coaxially provided with a reference ring, the reference ring is located below the mask plate, a plurality of first capacitive sensors are spaced apart and symmetrically arranged on the reference ring in the circumferential direction, the first capacitive sensors are used for detecting the distance between the mask plate, and the first capacitive sensors and the linear actuators are electrically connected with the processor.

[0007] By adopting the technical scheme, all the first capacitive sensors detect the distances between the various circumferential positions of the reference ring and the mask plate in real time, and transmit the distance data to the processor, the processor compares the distance data, judges the difference between the distance data, and further judges the deviation between the various circumferential positions of the reference ring and the mask plate. When the deviation exceeds the standard, the processor sends an instruction to the linear brake according to the size and direction of the deviation, the linear brake drives the wedge to move, and since the inclined surface on the wedge abuts against the movable table, the movement of the wedge drives the movable table to adjust the attitude in the three-dimensional space, and the position with larger deviation of the movable table is raised or lowered, and the first capacitive sensor is also adjusted accordingly, so as to compensate the parallelism error between the mask plate and the silicon wafer, thereby ensuring the parallelism between the mask plate and the silicon wafer during overlay, and improving the yield of the chip.

[0008] Preferably, a lifting cylinder is arranged below the bearing table, a bottom end of the lifting cylinder is fixed to a support body of the photolithography machine, and a top end of the lifting cylinder is fixedly connected with a lower surface of the bearing table.

[0009] By adopting the technical scheme, the lifting cylinder can control the lifting height of the bearing table according to the requirements of the photolithography process, thereby driving the bearing table, the movable table on the bearing table and the silicon wafer to adjust the position in the vertical direction, so that the distance between the silicon wafer and the mask plate can be quickly and coarsely adjusted.

[0010] Preferably, a flexible connecting piece is arranged between the movable table and the bearing table, the flexible connecting piece is used to connect the movable table and the bearing table, and allows the movable table to relatively move with respect to the bearing table.

[0011] By adopting the technical scheme, the flexible connecting piece provides the movable table with a degree of freedom of movement, and can adapt to the relative movement of the movable table when the wedge drives the movable table to adjust the attitude in the three-dimensional space. Meanwhile, the flexible connecting piece connects the movable table and the bearing table, which helps to prevent the movable table from being separated from the bearing table.

[0012] Preferably, the flexible connecting piece is a tension spring, a top end of the tension spring is fixedly connected with a lower surface of the movable table, and a bottom end of the tension spring is fixedly connected with an upper surface of the bearing table, and the tension spring drives the movable table to move close to the bearing table.

[0013] By adopting the technical scheme, the tension spring continuously applies a pulling force, so that the movable table and the inclined surface of the wedge are always closely fitted, which ensures that the movable table and the inclined surface will not be separated or have a gap when the wedge drives the movable table to adjust the attitude, thereby ensuring the accuracy and stability of the attitude adjustment of the movable table, and further improving the error compensation effect and the overlay precision.

[0014] Preferably, the lower edge of the movable platform peripheral wall is fixed in the circumferential direction and embedded with a plurality of pressure sensors corresponding to the wedges, the pressure sensors being used to detect the contact pressure between the movable platform and the inclined surface, and the pressure sensors being electrically connected to the processor.

[0015] By using the above technical solution, the pressure sensors can monitor the contact pressure between the movable platform and the inclined surface of the wedge in real time, and transmit the pressure data to the processor. The processor can determine whether the contact between the movable platform and the wedge is normal according to the pressure data. If an abnormal pressure condition occurs, the linear actuator can be adjusted in time to drive the wedge, so as to ensure the reliable contact between the movable platform and the wedge during the posture adjustment process, prevent the movable platform from being partially suspended during work, and improve the stability of the movable platform.

[0016] Preferably, the reference ring surrounds the silicon wafer, and a plurality of extension plates are arranged on the reference ring in the circumferential direction and symmetrically, the extension plates extending towards the axis of the reference ring, and the lower surface of the extension plate is provided with a second capacitive sensor for detecting the distance to the silicon wafer, and the second capacitive sensor is electrically connected to the processor.

[0017] By using the above technical solution, the second capacitive sensor can detect the distance between the silicon wafer and the extension plate in real time, and transmit the data to the processor. The processor can more comprehensively analyze the relative positional relationship between the silicon wafer and the mask plate by combining the distance data between the mask plate and the reference ring detected by the first capacitive sensor, so as to more accurately judge the parallelism error between the silicon wafer and the mask plate, and realize more accurate error compensation.

[0018] Preferably, the first capacitive sensor corresponds to the extension plate, the first capacitive sensor is fixedly connected to the upper surface of the extension plate, and the first capacitive sensor is aligned with the second capacitive sensor in the vertical direction.

[0019] By using the above technical solution, the processor can directly add the distance detected by the first capacitive sensor and the distance detected by the second capacitive sensor on the same extension plate, and compare the sum of the distances measured by the first capacitive sensors and the second capacitive sensors of different extension plates. In this way, the distance between each orientation of the silicon wafer and the mask plate can be more directly and accurately measured, and more accurate error compensation can be realized.

[0020] Preferably, the extension plate is slidably connected to the upper surface of the reference ring, the sliding direction of the extension plate is parallel to the radial direction of the reference ring, and the movable platform is further provided with a sliding assembly for driving the extension plate to slide.

[0021] Through the above technical scheme, when the photoetching machine exposes and processes the silicon wafer, the sliding assembly drives the extension plate to slide along the radial direction of the reference ring, adjusts the position of the extension plate, and moves the extension plate away from the top of the silicon wafer.

[0022] Preferably, the sliding assembly comprises a rotating ring, a movable rod, and a rotating driving member, the rotating ring is rotationally connected to the movable table, the axis of the rotating ring coincides with the axis of the reference ring, a plurality of waist-shaped holes are symmetrically and spaced apart in the circumferential direction of the rotating ring, one end of the waist-shaped hole is close to the center of the rotating ring, the other end of the waist-shaped hole is close to the edge of the rotating ring, the movable rod is movably connected in the waist-shaped hole, the movable rod is fixedly connected to the extension plate, and the rotating driving member is used to drive the rotating ring to rotate.

[0023] Through the above technical scheme, when the rotating driving member drives the rotating ring to rotate, the movable rod moves in the waist-shaped hole along the direction in which the waist-shaped hole is formed, forcing the extension plate to slide along the radial direction of the reference ring, thereby synchronously adjusting the positions of all the extension plates, so that all the extension plates can simultaneously enter or leave the top of the silicon wafer.

[0024] Preferably, the rotating driving member comprises a fixed frame, a motor, a gear, and a toothed ring, the toothed ring is coaxial with and fixedly connected to the rotating ring, the fixed frame is fixedly connected to the movable table, the motor is fixed to the fixed frame, the gear is coaxially fixed to the driving shaft of the motor, and the gear and the toothed ring are in meshing engagement.

[0025] Through the above technical scheme, the motor drives the gear to rotate, the gear and the toothed ring are in meshing engagement to drive the toothed ring to rotate, and the rotating ring fixedly connected to the toothed ring is further driven to rotate, thereby achieving the driving of the position adjustment of the extension plate.

[0026] In summary, the present application has at least one of the following beneficial technical effects:

[0027] 1. By arranging the wedge, the linear brake, the inclined surface, the movable table, the silicon wafer, the reference ring, and the first capacitive sensor, the first capacitive sensor monitors the distance between the reference ring and the mask plate in real time, the processor controls the linear brake to drive the wedge according to the data, and the movable table is driven by the inclined surface to adjust the three-dimensional posture, thereby compensating for the parallelism error between the mask plate and the silicon wafer, ensuring the parallelism of the surfaces of the two during overlay, and improving the yield of chips;

[0028] 2. By arranging the extension plate and the second capacitive sensor, the second capacitive sensor detects the distance between the silicon wafer and the extension plate, and the processor can more comprehensively and accurately analyze the relative positional relationship between the silicon wafer and the mask plate in combination with the data of the first capacitive sensor, thereby achieving more accurate error compensation and further improving the overlay accuracy;

[0029] 3. By setting up a rotating ring, a movable rod, an oblong hole, a fixed frame, a motor, a gear, and a gear ring, the motor drives the gear ring to rotate the rotating ring, and the movable rod moves in the oblong hole to drive the extension plate to slide along the radius of the reference ring, so as to achieve precise adjustment and synchronous action of the extension plate position, so that the extension plate can enter or leave the silicon wafer in a timely manner as needed, and minimize interference with the silicon wafer exposure process. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an error compensation system for a lithography machine provided in an embodiment of this application.

[0031] Figure 2 yes Figure 1 Enlarged view of part A

[0032] Figure 3 This is a cross-sectional schematic diagram reflecting the structure on the support platform in the embodiments of this application.

[0033] Figure 4 yes Figure 3 Enlarged view of section B.

[0034] Explanation of reference numerals in the attached drawings: 1. Support platform; 11. Wedge block; 111. Inclined surface; 12. Linear brake; 13. Lifting cylinder; 14. Tension spring; 2. Movable platform; 21. Reference ring; 22. Pressure sensor; 23. Extension plate; 231. First capacitive sensor; 232. Second capacitive sensor; 3. Sliding assembly; 31. Rotating ring; 311. Waist-shaped hole; 32. Movable rod; 33. Rotation drive component; 331. Fixing frame; 332. Motor; 333. Gear; 334. Gear ring; 4. Mask template; 5. Silicon wafer. Detailed Implementation

[0035] The following is in conjunction with the appendix Figures 1-4 This application will be described in further detail.

[0036] This application discloses an error compensation system for a lithography machine. (Refer to...) Figure 1 The system includes a support stage 1, a photomask 4, and a processor mounted on a lithography machine. A plurality of wedges 11 and linear brakes 12 are symmetrically and spaced apart along the circumferential direction on the upper surface of the support stage 1. In this embodiment, eight wedges 11 and eight linear brakes 12 are used. The linear brakes 12 are fixedly connected to the support stage 1, and the wedges 11 are movably connected to the support stage 1 along directions close to or away from the axis of symmetry. Each linear brake 12 corresponds to one wedge 11 and can drive the wedges 11 to move.

[0037] Reference Figure 1The upper surface of the wedge 11 is inclined with an inclined surface 111. All the inclined surfaces 111 of the wedges 11 together support the movable platform 2, and the lower edge of the peripheral wall of the movable platform 2 abuts against the inclined surface 111. The movable platform 2 is used to support the silicon wafer 5. The linear brake 12 adjusts the distance from the wedge 11 to the center of the support platform 1 by extending or retracting its output end, thereby changing the contact position between the movable platform 2 and the inclined surface 111, so as to adjust the height of the movable platform 2 at various positions in the circumferential direction.

[0038] Reference Figure 1 Several pressure sensors 22 are fixedly embedded in the lower edge of the perimeter wall of the movable platform 2 in the circumferential direction, and each pressure sensor 22 corresponds to a wedge 11. The pressure sensors 22 are used to detect the contact pressure between the movable platform 2 and the inclined surface 111, and the pressure sensors 22 are electrically connected to the processor. When the pressure sensor 22 detects that the pressure is too low, the processor can determine that the contact between the inclined surface 111 corresponding to the pressure sensor 22 and the movable platform 2 is unstable, and that the movable platform 2 is suspended at the inclined surface 111. Then, the processor controls the corresponding linear brake 12 to adjust the position of the wedge 11 until the movable platform 2 is properly supported, thereby ensuring the stability of the movable platform 2 during operation.

[0039] Reference Figure 1 and Figure 2 A reference ring 21 is coaxially mounted on the upper surface of the support platform 1, located below the mask template 4. A plurality of first capacitive sensors 231 are symmetrically and spaced along the circumferential direction on the reference ring 21. In this embodiment, eight first capacitive sensors 231 are used. The first capacitive sensors 231 are used to detect the distance between themselves and the mask template 4. Both the first capacitive sensors 231 and the linear brake 12 are electrically connected to the processor. Each first capacitive sensor 231 detects the distance between each circumferential position of the reference ring 21 and the mask template 4 in real time and transmits the distance data to the processor. The processor compares these distance data, determines the difference between the distance data, and then determines the deviation between each circumferential position of the reference ring 21 and the mask template 4. When the deviation exceeds the standard, the processor sends a command to the linear brake 12 according to the magnitude and direction of the difference. The linear brake 12 drives the wedge block 11 to move, adjusting the position of the movable block.

[0040] To achieve rapid coarse adjustment of the vertical position of the support platform 1 and the movable platform 2, and thus quickly adjust the approximate distance between the mask 4 and the silicon wafer 5, refer to... Figure 1 A lifting cylinder 13 is provided below the support platform 1. The bottom end of the lifting cylinder 13 is fixed to the support body of the lithography machine, and the top end of the lifting cylinder 13 is fixedly connected to the lower surface of the support platform 1.

[0041] To prevent the movable platform 2 from detaching from the support platform 1 and to improve the stability of the movable platform 2 relative to the support platform 1, refer toFigure 3 A flexible connector is provided between the movable platform 2 and the support platform 1. The flexible connector connects the movable platform 2 and the support platform 1 and allows the movable platform 2 and the support platform 1 to move relative to each other. Specifically, the flexible connector is a tension spring 14. The top end of the tension spring 14 is fixedly connected to the lower surface of the movable platform 2, and the bottom end is fixedly connected to the upper surface of the support platform 1. The tension spring 14 drives the movable platform 2 to move closer to the support platform 1. In this embodiment, eight tension springs 14 are arranged symmetrically and at intervals along the circumference of the support platform 1.

[0042] To more accurately detect the parallelism between silicon wafer 5 and photomask 4, refer to Figure 2 and Figure 4 A reference ring 21 surrounds the silicon wafer 5. Several extension plates 23 are symmetrically arranged at intervals along the circumference of the reference ring 21. Each extension plate 23 extends towards the axis of the reference ring 21. A second capacitive sensor 232 is disposed on the lower surface of each extension plate 23 to detect the distance to the silicon wafer 5. The second capacitive sensor 232 is electrically connected to the processor. A first capacitive sensor 231 corresponds one-to-one with each extension plate 23 and is fixedly connected to the upper surface of each extension plate 23. The first and second capacitive sensors 231 are aligned vertically. The distance detected by the first and second capacitive sensors 231 and 232 on the same extension plate 23 is only the distance directly reflected between the silicon wafer 5 and the photomask 4. The processor can directly add the distances detected by the first capacitive sensor 231 and the second capacitive sensor 232 on the same extension board 23, and compare the sum of the distances of the two capacitive sensors on different extension boards 23, so as to more directly and accurately determine the distance between the silicon wafer 5 and the mask 4 in the circumferential direction, and thus more accurately detect the parallelism between the silicon wafer 5 and the mask 4.

[0043] To prevent the extension plate 23 from hindering the exposure process of the silicon wafer 5, refer to Figure 2 and Figure 4 The extension plate 23 is slidably connected to the upper surface of the reference ring 21, with the sliding direction parallel to the radial direction of the reference ring 21. A sliding assembly 3 is provided on the movable platform 2, which drives the extension plate 23 to slide. The sliding assembly 3 includes a rotating ring 31, a movable rod 32, and a rotating drive component 33. The rotating ring 31 is rotatably connected to the movable platform 2, and its axis coincides with that of the reference ring 21. The rotating ring 31 has several symmetrically spaced, waist-shaped holes 311 along its circumference. The waist-shaped holes 311 are arc-shaped, with one end close to the edge of the rotating ring 31. The movable rod 32 is movably connected within the waist-shaped holes 311 and is fixedly connected to the extension plate 23. The rotating drive component 33 drives the rotating ring 31 to rotate.

[0044] Reference Figure 2 Figure 4The rotary drive component 33 includes a fixed frame 331, a motor 332, a gear 333, and a gear ring 334. The gear ring 334 is coaxial with and fixedly connected to the rotating ring 31. The fixed frame 331 is fixedly connected to the movable stage 2. The motor 332 is fixed on the fixed frame 331. The gear 333 is coaxially fixed with the drive shaft of the motor 332, and the gear 333 meshes with the gear ring 334. The motor 332 drives the gear 333 to rotate, which in turn drives the gear ring 334 and the rotating ring 31 to rotate. The movable rod 32 moves within the oblong hole 311, forcing the extension plate 23 to slide along the radius of the reference ring 21, thereby achieving synchronous adjustment of the positions of all extension plates 23 until all extension plates 23 are removed from above the silicon wafer 5. Specifically, several fixed frames 331 are spaced apart and symmetrically arranged in the circumferential direction of the movable platform 2. The motor 332 and the gear ring 334 are mounted on one of the fixed frames 331, and counterweights are fixedly mounted on the other fixed frames 331. The mass of the counterweights is equal to the sum of the masses of the motor 332 and the gear ring 334. The overall center of gravity of the motor 332 and the gear ring 334 and the center of gravity of all the counterweights are symmetrical about the axis of the movable platform 2, thereby improving the stability of the movable platform 2 in the circumferential direction.

[0045] The implementation principle of the error compensation system for a lithography machine according to an embodiment of this application is as follows: Before the silicon wafer 5 is exposed, the lifting cylinder 13 first quickly and roughly adjusts the height of the support stage 1, bringing the silicon wafer 5 close to the photomask 4. Then, the motor 332 drives the gear 333 to rotate, and the gear 333 meshes with the gear ring 334 to drive the rotating ring 31 to rotate. The oblong hole 311 rotates accordingly, forcing the movable rod 32 to slide the extension plate 23, which extends above the silicon wafer 5. The first capacitive sensor 231 detects the distance to the photomask 4, and the second capacitive sensor 232 detects the distance to the silicon wafer 5. The processor adds the distances detected by the first capacitive sensor 231 and the second capacitive sensor 232 on the same extension plate 23, and compares the sum of the distances of the two capacitive sensors on different extension plates 23, thereby directly and accurately determining the distance between the silicon wafer 5 and the photomask 4 in the circumferential direction. This allows for the determination of the deviation between the various circumferential positions of the silicon wafer 5 and the photomask 4. When the deviation exceeds the standard, the processor sends a command to the linear brake 12 based on the magnitude and direction of the difference. The linear brake 12 drives the wedge 11 to move, adjusting the stage 2 and the silicon wafer 5. During the exposure process on the silicon wafer 5, the motor 332 drives the gear 333 to rotate in the opposite direction, causing the extension plate 23 to move in the opposite direction and disengage from the silicon wafer 5. After the extension plate 23 moves out, the first capacitive sensor 231 remains on the reference ring 21, allowing it to continue detecting the distance to the mask 4 to determine the stability of the parallelism between the stage 2 and the mask 4 during the exposure process. This ensures the parallelism between the mask 4 and the surface of the silicon wafer 5 during overlay, thereby improving the chip yield.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An error compensation system for a lithography machine, comprising a support stage (1), a photomask (4), and a processor mounted on the lithography machine, characterized in that: The upper surface of the support platform (1) is symmetrically and spaced along the circumferential direction with several wedges (11) and linear brakes (12). The linear brakes (12) are fixedly connected to the support platform (1). The wedges (11) are movably connected to the support platform (1) along the direction close to or away from the axis of symmetry. The linear brakes (12) correspond one-to-one with the wedges (11) and can drive the wedges (11) to move. The upper surface of the wedges (11) is inclined with inclined surfaces (111). All the inclined surfaces (111) of the wedges (11) together support the movable platform (2). The lower edge of the periphery of the movable stage (2) abuts against the inclined surface (111), and the movable stage (2) is used to support the silicon wafer (5); a reference ring (21) is coaxially arranged on the upper surface of the support stage (1), the reference ring (21) is located below the mask (4), and a plurality of first capacitive sensors (231) are arranged symmetrically and at intervals along the circumferential direction on the reference ring (21). The first capacitive sensors (231) are used to detect the distance between themselves and the mask (4). The first capacitive sensors (231) and the linear brake (12) are both electrically connected to the processor.

2. The error compensation system for a lithography machine according to claim 1, characterized in that: A lifting cylinder (13) is provided below the support platform (1). The bottom end of the lifting cylinder (13) is fixed to the support body of the lithography machine, and the top end of the lifting cylinder (13) is fixedly connected to the lower surface of the support platform (1).

3. The error compensation system for a lithography machine according to claim 1, characterized in that: A flexible connector is provided between the movable platform (2) and the support platform (1). The flexible connector is used to connect the movable platform (2) and the support platform (1) and allows the movable platform (2) and the support platform (1) to move relative to each other.

4. The error compensation system for a lithography machine according to claim 3, characterized in that: The flexible connector is a tension spring (14). The top end of the tension spring (14) is fixedly connected to the lower surface of the movable platform (2), and the bottom end of the tension spring (14) is fixedly connected to the upper surface of the support platform (1). The tension spring (14) drives the movable platform (2) to move closer to the support platform (1).

5. The error compensation system for a lithography machine according to claim 1, characterized in that: The lower edge of the periphery of the movable platform (2) is fixed and embedded with several pressure sensors (22) in the circumferential direction. The pressure sensors (22) correspond one-to-one with the wedges (11). The pressure sensors (22) are used to detect the contact pressure between the movable platform (2) and the inclined surface (111). The pressure sensors (22) are electrically connected to the processor.

6. The error compensation system for a lithography machine according to claim 1, characterized in that: The reference ring (21) surrounds the silicon wafer (5). Several extension plates (23) are symmetrically arranged at intervals along the circumferential direction on the reference ring (21). The extension plates (23) extend towards the axis of the reference ring (21). A second capacitive sensor (232) is provided on the lower surface of the extension plate (23). The second capacitive sensor (232) is used to detect the distance of the silicon wafer (5). The second capacitive sensor (232) is electrically connected to the processor.

7. The error compensation system for a lithography machine according to claim 6, characterized in that: The first capacitive sensor (231) corresponds one-to-one with the extension plate (23). The first capacitive sensor (231) is fixedly connected to the upper surface of the extension plate (23). The first capacitive sensor (231) and the second capacitive sensor (232) are aligned in the vertical direction.

8. The error compensation system for a lithography machine according to claim 6, characterized in that: The extension plate (23) is slidably connected to the upper surface of the reference ring (21), and the sliding direction of the extension plate (23) is parallel to the radial direction of the reference ring (21). The movable platform (2) is also provided with a sliding assembly (3) for driving the extension plate (23) to slide.

9. The error compensation system for a lithography machine according to claim 8, characterized in that: The sliding assembly (3) includes a rotating ring (31), a movable rod (32), and a rotating drive (33). The rotating ring (31) is rotatably connected to the movable platform (2). The axis of the rotating ring (31) coincides with that of the reference ring (21). The rotating ring (31) has several waist-shaped holes (311) spaced apart and symmetrically arranged along the circumferential direction. One end of the waist-shaped hole (311) is close to the center of the rotating ring (31), and the other end of the waist-shaped hole (311) is close to the edge of the rotating ring (31). The movable rod (32) is movably connected in the waist-shaped hole (311). The movable rod (32) is fixedly connected to the extension plate (23). The rotating drive (33) is used to drive the rotating ring (31) to rotate.

10. The error compensation system for a lithography machine according to claim 9, characterized in that: The rotary drive component (33) includes a fixed frame (331), a motor (332), a gear (333), and a gear ring (334). The gear ring (334) is coaxial with and fixedly connected to the rotating ring (31). The fixed frame (331) is fixedly connected to the movable platform (2). The motor (332) is fixed on the fixed frame (331). The gear (333) is coaxially fixed with the drive shaft of the motor (332). The gear (333) meshes with the gear ring (334).

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