Method for monitoring and compensating horizontal calibration error of LDI exposure machine

Abstract

The invention discloses a method for monitoring and compensating a horizontal calibration error of an LDI exposure machine, and the method comprises the steps: S1, carrying out the horizontal calibration of a platform, a camera and an exposure lens before exposing a material plate; s2, converting each measurement point on the graphic coordinate system where the material plate is located to a platform coordinate system, and obtaining the theoretical position coordinate of each measurement point; exposure is carried out after horizontal calibration is completed, expansion, contraction and rotation errors of a platform at an exposure position and position calibration errors of a reference lens and a reference camera are calculated and compensated by fitting difference values of theoretical positions and actual positions of all measurement points, and calibration errors of magnification and angle of the exposure lens and the position relation of the exposure lens are monitored and compensated; and the grid error of the platform at the exposure position is monitored and compensated, so that the error generated by each subsystem in the horizontal direction can be decomposed and compensated, and the accuracy of overlay is finally ensured.

Description

Technical Field

[0001] The invention relates to the field of semiconductor lithography equipment, and in particular to a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine. Background Art

[0002] Overlay is an important indicator for the horizontal acceptance of LDI exposure machines. The exposure process of the exposure machine is such as a double-table direct writing exposure machine published in a Chinese patent (publication number CN211741826U), which is equipped with exposure mechanism, moving workpiece table, alignment system and other components. Due to the influence of horizontal calibration error factors, the existing LDI exposure machine will cause a certain deviation between the center position of the circle and the ring during the overlay test. Excessive overlay error will reduce the yield rate in subsequent production.

[0003] And because the horizontal error value is composed of the error coupling of multiple subsystems, the existing scheme cannot analyze the existing data of overlay without adding additional sensors, decompose the errors generated by each subsystem and compensate for them, so as to ultimately ensure the accuracy of overlay; and it is impossible to intuitively derive the contribution of each subsystem to the error through test data, and it is also impossible to make targeted compensation.

[0004] Therefore, those skilled in the art provide a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine to solve the problems raised in the above background technology. Summary of the invention

[0005] The object of the present invention is to provide a method for monitoring and compensating the horizontal calibration error of an LDI exposure machine, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] S1: Before exposing the material plate, calibrate the platform, camera and exposure lens horizontally;

[0008] S2: Convert each measuring point on the graphic coordinate system where the material board is located to the platform coordinate system to obtain the theoretical position coordinates of each measuring point;

[0009] S3: Use an exposure lens to expose the ring and circle at each measuring point on the material board respectively, use a camera to capture the deviation between the center of the ring and the circle, the camera obtains the actual position coordinates of the ring in the platform coordinate system, and calculates the difference between the actual position and the theoretical position of each measuring point;

[0010] S4: fitting the difference between the theoretical position and the actual position of each measuring point, calculating and compensating the expansion and contraction, rotation error of the platform at the exposure position and the calibration error of the reference lens and the reference camera position, and obtaining a first residual value;

[0011] S5: Calculate and compensate for the calibration errors of the exposure lens magnification, angle calibration, and exposure lens position relationship based on the first residual value to obtain a second residual value;

[0012] S6: Calculate and compensate for the grid error of the platform at the exposure position based on the second residual value.

[0013] As a further solution of the present invention: in step S2, before exposure, the coordinates of each measuring point on the pattern to be exposed are transformed using an affine transformation model to obtain the position of each measuring point on the pattern to be exposed in the platform coordinate system under a theoretical state.

[0014] As a further solution of the present invention: wherein step S3 specifically includes:

[0015] S3-1: The deviation between the ring captured by the camera and the center of the circle is the threading error. The camera divides the measurement points according to their positional relationship in the platform coordinate system, and obtains the scanning cycle, exposure lens, and strip number to which each measurement point belongs;

[0016] S3-2: The platform coordinates of the theoretical position of each measuring point are subtracted from the platform coordinates of each measuring point actually captured by the camera to obtain the difference between the theoretical position and the actual position of each measuring point.

[0017] As a further solution of the present invention: wherein step S4 specifically includes:

[0018] S4-1: Use the affine transformation model to fit the difference between the theoretical and actual positions of each measurement point according to the least squares method, and compensate the fitting coefficients to the affine transformation model respectively;

[0019] S4-2: Obtain a first residual value after removing the expansion and contraction and rotation errors of the platform at the exposure position and the calibration errors of the reference lens and the reference camera positions.

[0020] As a further solution of the present invention: wherein step S5 specifically includes:

[0021] S5-1: According to the positional relationship of the measurement points in the exposure lens coordinate system, the first residual value is fitted using a first-order linear model according to the scanning cycle, exposure lens, and strip number, using the least square method to obtain the lens X-direction magnification calibration error, lens angle calibration error, and positional relationship calibration error of each lens of each exposure lens;

[0022] S5-2: Compensating the lens magnification calibration error, the lens angle calibration error, and the lens position relationship calibration error to the lens magnification and angle calibration parameters and the position relationship between the lenses respectively;

[0023] S5-3: Obtain a second residual value after removing the lens magnification and angle calibration of the exposure lens and the calibration error of the exposure lens position relationship.

[0024] As a further solution of the present invention: wherein step S6 specifically includes:

[0025] S6-1: Calculate the X and Y coordinates of the platform at the exposure measurement point based on the actual platform coordinates of each measurement point, and correspond the second residual value after removing the lens magnification, angle calibration and exposure lens position relationship calibration errors of the exposure lens to the platform position one by one, and average the grid errors of the platform measurement points at similar positions to represent the effective value of the platform grid error at the exposure measurement point;

[0026] S6-2: The effective value of the grid data at each position of the platform is compensated to the platform grid error of the platform at the exposure position, and the remaining positions in the grid are filled in the form of linear interpolation.

[0027] As a further solution of the present invention: it also includes S7: after compensating the error amount in steps S4-S6, re-exposing the plate, verifying whether the compensation result is effective, and judging the convergence according to the compensation result;

[0028] S8: Calculate and compensate for the calibration residual of the alignment system.

[0029] As a further solution of the present invention: in step S7, it is verified whether the compensation result is effective, including: platform expansion and contraction, rotation error, reference lens and reference camera position relationship error, exposure lens magnification and angle error, position relationship between exposure lenses, and grid error of the platform at the exposure position.

[0030] As a further solution of the present invention: wherein step S8 specifically includes:

[0031] S8-1: First, expose the ring pattern, then select four points in the ring layer as alignment points to complete the alignment, then expose the circle, and finally use the alignment camera to measure the X / Y center deviation of the ring and circle. The error between the center of the ring and the circle is caused by the calibration error of the alignment system;

[0032] S8-2: Fit each point on the material board to obtain the calibration residual of the alignment system, and compensate the calibration residual into the alignment system. When using the alignment function for subsequent exposure, the calibration residual compensation parameters of the alignment system must be added to reduce the overlay deviation between the ring and the center of the circle, so as to optimize the overlay performance of the single machine.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] After completing the horizontal calibration, exposure is carried out. By fitting the difference between the theoretical position and the actual position of each measuring point, the expansion and contraction, rotation error of the platform at the exposure position and the calibration error of the reference lens and the reference camera position are calculated and compensated. The calibration errors of the exposure lens magnification, angle and exposure lens position relationship are monitored and compensated. The grid error of the platform at the exposure position is monitored and compensated. The errors generated by each subsystem in the horizontal direction can be decomposed and compensated, ultimately ensuring the accuracy of overlay. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a schematic diagram of the implementation steps of a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine.

[0036] Figure 2 A schematic diagram of an exposure pattern in a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine.

[0037] Figure 3 Schematic diagram of an exposure lens and a motion platform in a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine.

[0038] Figure 4 The present invention is a flow chart of overlay test in a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a method for monitoring and compensating horizontal calibration errors of an LDI exposure machine, comprising the following steps:

[0041] S1: Before exposing the material plate, calibrate the platform, camera and exposure lens horizontally.

[0042] like Figure 2-Figure 3 As shown, S2: convert each measuring point on the graphic coordinate system where the material board is located to the platform coordinate system to obtain the theoretical position coordinates of each measuring point;

[0043] Due to the influence of the motion error of the platform at the exposure position and the calibration error of the exposure lens, the exposed pattern deviates from the theoretical value. Before exposure, the affine transformation model is used to transform the coordinates of each measurement point on the exposed pattern to obtain the position of each measurement point of the exposed pattern in the platform coordinate system under the theoretical state. The matrix used includes but is not limited to:

[0044]

[0045] Among them, mx and my represent the expansion and contraction of the platform in the X and Y directions at the exposure position, rx and ry represent the rotation of the platform at the exposure position; tx and ty represent the overall translation of the platform at the exposure position. The positions of the measurement points on the exposure graph in the graph coordinate system are transformed by the affine transformation model Matrix 1x and Matrix 1y The position coordinate set Xl, Yl of each measuring point of the exposure pattern in the platform coordinate system under the theoretical state can be obtained, where Xl = {Xl1, Xl2...Xl n},Yl={Yl1,Yl2……Yl n}

[0046] S3: Use an exposure lens to expose the ring and circle at each measuring point on the material board respectively, use a camera to capture the deviation between the center of the ring and the circle, the camera obtains the actual position coordinates of the ring in the platform coordinate system, and calculates the difference between the actual position and the theoretical position of each measuring point;

[0047] S3-1: When the pattern to be exposed is not aligned with a camera, an exposure lens is used to expose the ring and circle at each measuring point on the material plate. The camera is used to capture the deviations errx1 and erry1 between the ring and the center of the circle. The camera obtains the actual position coordinate set Xr and Yr of the ring in the platform coordinate system. The deviations errx1 and erry1 between the ring and the center of the circle obtained by the camera are the threading overlay error. The camera is a CCD alignment camera. The threading overlay error characterizes the repeatability performance of the platform in a short period of time. If the threading overlay exceeds 3um, it is necessary to check for abnormalities.

[0048] The camera divides the measurement points according to their positional relationship in the platform coordinate system, and obtains the scanning cycle, exposure lens, and strip number to which each measurement point belongs.

[0049] S3-2: The position Xl and Yl of each measuring point of the exposure pattern in the platform coordinate system under the theoretical state minus the actual position coordinates Xr and Yr of the ring obtained by the camera in the platform coordinate system:

[0050] ①Xl-Xr=Errx1

[0051] ②Yl-Yr=Erry1

[0052] The difference set Errx1 and Erry1 between the theoretical position and the actual position of each measuring point is obtained, where Errx1 = {Errx11, Errx12, ... Errx1 n}, Erry1={Erry11,Erry12,...Erry1 n}.

[0053] S4: Fitting the difference between the theoretical position and the actual position of each measurement point, calculating and compensating the expansion and contraction, rotation error of the platform at the exposure position and the calibration error of the reference lens and the reference camera position, and obtaining a first residual value, specifically including:

[0054] S4-1: Use the affine transformation model to fit the difference between the theoretical and actual positions of each measurement point, Errx1 and Erry1, by the least squares method: The two models Fit Errx1 and Erry1 to the coordinates respectively. According to the principle of least squares method, the least squares method finds the best function matching of the data by minimizing the sum of squares of errors, so that the sum of squares of errors between the obtained data and the actual data is minimized. However, the model cannot fully express the distribution of Errx1 and Erry1 errors through least squares fitting, so there will be first residual values ​​Errx2 and Erry2.

[0055]

[0056] Among them, xl and Yl represent the position coordinate set of each measurement point of the exposure pattern in the platform coordinate system under the theoretical state, Xl1, Xl2, ... Xl n is a component of the set Xl, Yl1, Yl2, ...Yl n is a component of the Yl set, Errx11, Errx12, ... Errx1 n It is a component of Errx1 set, Erry11, Erry12, ... Erry1 n It is a component of the Erry1 set. Mx1 and My1 represent the difference between the expansion and contraction of the platform in the X and Y directions at the exposure position and the theoretical value. Rx1 and Ry1 represent the difference between the rotation of the platform at the exposure position and the theoretical value. Tx1 and Ty1 represent the difference between the overall translation of the platform at the exposure position and the theoretical value.

[0057] Then name the fitted coefficients Matrix 11x and Matrix 11y , and compensate the fitting coefficients to the affine transformation model Matrix in step S2 1x and Matrix 1y, which is used to remove the expansion, contraction, rotation error of the platform at the exposure position and the calibration error of the reference lens and reference camera position, namely:

[0058]

[0059] S4-2: The residual value after removing the expansion and contraction of the platform at the exposure position, the rotation error, and the calibration error of the reference lens and the reference camera position is set as the first residual value Errx2 and Erry2. According to the principle of least squares method, the model cannot express the error distribution 100% through least squares fitting, so there will be first residual values ​​Errx2 and Erry2:

[0060]

[0061] S5: After removing the expansion and contraction, rotation errors of the platform at the exposure position and the calibration errors of the reference lens and reference camera positions, calculate and compensate for the calibration errors of the exposure lens magnification, angle calibration and exposure lens position relationship, specifically including:

[0062] S5-1: According to the positional relationship of the measurement points in the exposure lens coordinate system, the first residual values ​​Errx2 and Erry2 are respectively fitted using a first-order linear model according to the scanning cycle, exposure lens, and strip number, using the least squares method to obtain the lens X-direction magnification calibration error, lens angle calibration error, and lens position relationship calibration error of each exposure lens: The two models Errx2 and Erry2 are fitted for the coordinates respectively. According to the principle of least squares method, the model cannot fully express the distribution of Errx2 and Erry2 errors through least squares fitting, so there will be second residual values ​​Errx3 and Erry3.

[0063]

[0064] Among them, x is the position information of each measurement point in the exposure lens coordinate system, x1, x2, ..., x n is a component of the x set, and is obtained by: using the coordinate relationship of each measurement point in the platform coordinate system and the scanning cycle, exposure lens, and strip number information to reversely infer the position of each measurement point in the lens coordinate system; Mx(len) is the lens magnification calibration error; Rx(len) is the lens angle calibration error; Tx2, Ty2 are the calibration errors of the position relationship of each lens, Errx21, Errx22, ... Errx2 n It is a component of Errx2 set, Erry21, Erry22, ... Erry2 n Part of the Erry2 collection.

[0065] S5-2: Compensating the lens magnification calibration error, the lens angle calibration error, and the lens position relationship calibration error to the lens magnification and angle calibration parameters and the position relationship between the lenses respectively;

[0066] S5-3: The residual values ​​of the first residual values ​​Errx2 and Erry2 after removing the exposure lens magnification, angle calibration and exposure lens position relationship calibration errors are set as the second residual values ​​Errx3 and Erry3. According to the principle of least squares method, the least squares method seeks the best function matching of the data by minimizing the sum of squares of the errors, so that the sum of squares of the errors between the obtained data and the actual data is minimized. However, the model cannot fully express the distribution of Errx2 and Erry2 errors through least squares fitting, so there will be second residual values ​​Errx3 and Erry3:

[0067]

[0068] S6: After removing the calibration errors of the lens magnification and angle calibration of the exposure lens and the position relationship of the exposure lens, the grid error of the platform at the exposure position is calculated and compensated, specifically including:

[0069] S6-1: Since the first-order and zero-order errors of the platform at the exposure position are removed in step S4, but the remaining high-order errors are not compensated, the X and Y coordinates of the platform at the exposure measurement point are calculated according to the actual platform coordinates of each measurement point, and the second residual values ​​Errx3 and Erry3 of each measurement point are matched with the platform position one by one, and the grid errors of the measurement points at the platform's close position are averaged to represent the effective value of the grid error of the platform position at the exposure measurement point. For example, the grid errors of the measurement points within 100um of the platform position are averaged, and the calculation equation is:

[0070] Err pos1 =(err pos1 +err pos2 +err pos3 +…+err posn ) / n

[0071] Among them, Err pos1 Indicates the effective value of the platform grid when exposing the measurement point, err pos1 、err pos2 、err pos3 , ..., err posn It represents the grid value at the position close to the platform when the exposure measurement point is taken. Thus, a set of grid error values ​​can be obtained in both the X-axis and Y-axis directions of the platform.

[0072] S6-2: The effective value of the grid data at each position of the platform is compensated to the platform grid error of the platform at the exposure position, so that the platform movement can be accurately moved to the theoretical position, and the remaining positions in the grid are filled in the form of linear interpolation.

[0073] S7: After compensating for the errors in steps S4-S6, re-expose the plate to verify whether the compensation results are effective, and judge the convergence based on the compensation results: if the platform expansion, contraction, and rotation errors converge to 4E-07, and the positional relationship error between the reference lens and the reference camera converges to within 0.4um, then step S4 is considered to be fully compensated; if the exposure lens magnification and angle errors converge to 3E-05, and the positional relationship between the exposure lenses converges to within 0.3um, then step S5 is considered to be fully compensated; if the average values ​​of the grid errors X and Y at the platform at the exposure position converge to within 0.3um, then step S6 is considered to be fully compensated, otherwise it is necessary to continue iterating or find the cause of the abnormality.

[0074] S8: After verifying that the compensation is effective and converged, the plate is replaced again to expose the ring and circle on the material plate, and the calibration residual of the alignment system is calculated and compensated, including:

[0075] S8-1: First expose the ring pattern, such as Figure 4 Ring 1; then select four points in the ring layer as alignment points to complete the alignment, such as Figure 4 Ring 2; then expose the circle, such as Figure 4 Circle 3; Finally, the alignment camera is used to measure the X / Y center deviations errx2 and erry2 of the ring and circle. The center errors of the ring and circle are caused by the calibration error of the alignment system.

[0076] S8-2: Fitting each point on the material surface:

[0077]

[0078] Get the calibration residual Matrix of the alignment system 2x 、Matrix 2y :

[0079]

[0080] Where X2 and Y2 represent the theoretical position of the ring in the platform coordinate system, X21, X21, ..., X2 n is a component of the set X2, Y21, Y21, ..., Y2 n It is a component of the Y2 set; errx21, errx22, ..., errx2 n is the component of errx2 set, erry21, erry22, ..., erry2 nIt is a component of the erry2 set; Mx2 and My2 represent the difference between the expansion and contraction of the alignment system in the X and Y directions and the theoretical value; Rx2 and Ry2 represent the difference between the rotation of the alignment system at the exposure position and the theoretical value; Tx2 and Ty2 represent the difference between the overall translation of the alignment system and the theoretical value;

[0081] The calibration residual compensation is added to the alignment system. When the alignment function is used for subsequent exposure, the calibration residual compensation parameters of the alignment system must be added to reduce the overlay deviation between the ring and the center of the circle, so as to optimize the overlay performance of the single machine.

[0082] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for monitoring and compensating horizontal calibration errors of an LDI exposure machine, characterized in that: The following steps are involved: S1: Before exposing the material plate, calibrate the platform, camera and exposure lens horizontally; S2: Convert each measuring point on the graphic coordinate system where the material board is located to the platform coordinate system to obtain the theoretical position coordinates of each measuring point; S3: Use an exposure lens to expose the ring and circle at each measuring point on the material board respectively, use a camera to capture the deviation between the center of the ring and the circle, the camera obtains the actual position coordinates of the ring in the platform coordinate system, and calculates the difference between the actual position and the theoretical position of each measuring point; S4: fitting the difference between the theoretical position and the actual position of each measuring point, calculating and compensating the expansion and contraction, rotation error of the platform at the exposure position and the calibration error of the reference lens and the reference camera position, and obtaining a first residual value; S5: Calculate and compensate for the calibration errors of the exposure lens magnification, angle calibration, and exposure lens position relationship based on the first residual value to obtain a second residual value; S6: Calculate and compensate for the grid error of the platform at the exposure position based on the second residual value.

2. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: In step S2, before exposure, the coordinates of each measuring point on the pattern to be exposed are transformed using an affine transformation model to obtain the position of each measuring point on the pattern to be exposed in the platform coordinate system under a theoretical state.

3. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: Wherein step S3 specifically comprises: S3-1: The deviation between the ring captured by the camera and the center of the circle is the threading error. The camera divides the measurement points according to their positional relationship in the platform coordinate system, and obtains the scanning cycle, exposure lens, and strip number to which each measurement point belongs; S3-2: The platform coordinates of the theoretical position of each measuring point are subtracted from the platform coordinates of each measuring point actually captured by the camera to obtain the difference between the theoretical position and the actual position of each measuring point.

4. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: Wherein step S4 specifically comprises: S4-1: Use the affine transformation model to fit the difference between the theoretical and actual positions of each measurement point according to the least squares method, and compensate the fitting coefficients to the affine transformation model respectively; S4-2: Obtain a first residual value after removing the expansion and contraction and rotation errors of the platform at the exposure position and the calibration errors of the reference lens and the reference camera positions.

5. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: Wherein step S5 specifically comprises: S5-1: According to the positional relationship of the measurement points in the exposure lens coordinate system, the first residual value is fitted using a first-order linear model according to the scanning cycle, exposure lens, and strip number, using the least square method to obtain the lens X-direction magnification calibration error, lens angle calibration error, and positional relationship calibration error of each lens of each exposure lens; S5-2: Compensating the lens magnification calibration error, the lens angle calibration error, and the lens position relationship calibration error to the lens magnification and angle calibration parameters and the position relationship between the lenses respectively; S5-3: Obtain a second residual value after removing the lens magnification and angle calibration of the exposure lens and the calibration error of the exposure lens position relationship.

6. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: Wherein step S6 specifically comprises: S6-1: Calculate the X and Y coordinates of the platform at the exposure measurement point based on the actual platform coordinates of each measurement point, and correspond the second residual value after removing the lens magnification, angle calibration and exposure lens position relationship calibration errors of the exposure lens to the platform position one by one, and average the grid errors of the platform measurement points at similar positions to represent the effective value of the platform grid error at the exposure measurement point; S6-2: The effective value of the grid data at each position of the platform is compensated to the platform grid error of the platform at the exposure position, and the remaining positions in the grid are filled in the form of linear interpolation.

7. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 1, characterized in that: The process further includes S7: after compensating the error in steps S4-S6, re-exposing the plate, verifying whether the compensation result is effective, and judging the convergence according to the compensation result; S8: Calculate and compensate for the calibration residual of the alignment system.

8. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 7, characterized in that: In step S7, it is verified whether the compensation result is effective, including: platform expansion and contraction, rotation error, reference lens and reference camera position relationship error, exposure lens magnification and angle error, position relationship between exposure lenses, and platform grid error at the exposure position.

9. The method for monitoring and compensating horizontal calibration errors of an LDI exposure machine according to claim 7, characterized in that: Wherein step S8 specifically comprises: S8-1: First, expose the ring pattern, then select four points in the ring layer as alignment points to complete the alignment, then expose the circle, and finally use the alignment camera to measure the X / Y center deviation of the ring and circle. The center error of the ring and circle is caused by the calibration error of the alignment system; S8-2: Fit each point on the material board to obtain the calibration residual of the alignment system, and compensate the calibration residual into the alignment system. When using the alignment function for subsequent exposure, the calibration residual compensation parameters of the alignment system must be added to reduce the overlay deviation between the ring and the center of the circle, so as to optimize the overlay performance of the single machine.

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