Multi-spot zero deviation calibration method

Abstract

The present invention provides a multi-spot zero deviation calibration method, comprising: providing a substrate having at least four measuring points on the substrate; a focusing and leveling system projects the same light beam onto each of the measuring points in sequence for a first measurement, the light beam comprising at least two measuring spots, each time projected onto the measuring point, the same measuring spot is aligned with the measuring point, and first position information of a corresponding position on the substrate measured by at least one measuring spot is obtained; the substrate is horizontally rotated 180°, and second position information of a corresponding position on the substrate measured by at least one measuring spot is obtained; and a zero deviation value of each measuring spot is calculated using the first position information and the second position information corresponding to each measuring point. The present invention improves the calibration accuracy of the zero deviation of multiple light spots.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a multi-spot zero deviation calibration method. Background Art

[0002] The integration of a lithography machine requires a series of measurements and calibrations, which measure and calibrate a series of machine constants to ensure the machine operates in the optimal posture and achieve the best results. In the focusing and leveling system, when multiple measurement spots are used to detect the vertical position information of the substrate exposure surface, due to factors such as the optical deviation of the light path through which each measurement spot passes and the deviation of the characteristics of the light path detection channel, there will be deviations between the actual measurement values ​​measured by each measurement spot when measuring the same height. In order to eliminate this deviation during the actual measurement process, it is necessary to measure the zero-point deviation of each measurement spot, and then use the zero-point deviation value of each measurement spot to calibrate the respective height measurement value. Therefore, the zero-point deviation between each measurement spot is one of the machine constants that needs to be measured and calibrated.

[0003] Figure 1 For a schematic diagram of the deviation between the zero plane of multiple measurement spots in the focusing and leveling system and any ideal plane, please refer to Figure 1 Due to the existence of assembly deviation and measurement deviation, the height difference of the zero plane 11 of multiple measurement spots relative to any ideal plane 10 is different, which leads to the introduction of deviation when the lithography machine tests the substrate surface shape. Figure 2 For a schematic diagram of the deviation of the zero plane of the two measurement spots in the focusing and leveling system, please refer to Figure 2 , a substrate 21 is placed on the workpiece stage 20 for measurement. The flatness of the substrate 21 will affect the measurement results of different measurement spots. If the surface morphology of the substrate 21 is undulating, that is, there is a substrate wedge deviation, the zero plane 22 of the two measurement spots will deviate; and during the movement of the substrate 21 during measurement, the substrate 21 also has a scanning tilt deviation, and the scanning tilt deviation will also cause a deviation in the zero plane of the measurement spot. Inaccurate measurement information will make it difficult to accurately calibrate the zero position deviation of the measurement spot. That is, during the measurement process, both the substrate scanning tilt deviation and the substrate wedge deviation will affect the calibration accuracy of the zero position deviation of the measurement spot. If the calibration accuracy of the zero position deviation of the measurement spot is low, severe cases will cause exposure defocus. Summary of the Invention

[0004] The object of the present invention is to provide a multi-spot zero deviation calibration method to improve the calibration accuracy of the multi-spot zero deviation.

[0005] In order to achieve the above object, the present invention provides a multi-spot zero deviation calibration method, comprising:

[0006] providing a substrate having at least four measurement points thereon;

[0007] The focusing and leveling system projects the same light beam onto each of the measurement points in sequence for a first measurement, wherein the light beam includes at least two measurement spots. Each time the light beam is projected onto the measurement point, the same measurement spot is aligned with the measurement point, and first position information of a corresponding position on the substrate measured by at least one measurement spot is obtained.

[0008] The substrate is horizontally rotated 180 degrees, and the focusing and leveling system projects the light beam onto each of the measurement points in sequence for a second measurement, wherein each time the light beam is projected onto the measurement point, the same measurement spot is aligned with the measurement point, and second position information of a corresponding position on the substrate measured by at least one measurement spot is obtained;

[0009] The zero position deviation value of each measuring light spot is calculated using the first position information and the second position information corresponding to each measuring point.

[0010] Optionally, the substrate has at least two measurement point groups, each measurement point group includes at least one pair of measurement points, each pair of measurement points is symmetrically arranged relative to the center of the substrate, the centers of all measurement points in each measurement point group are located on the same virtual line, and the virtual lines of any two measurement point groups do not overlap.

[0011] Optionally, the first position information and the second position information are both vertical height values. In the first measurement and the second measurement, each time the projection is onto the measurement point, the vertical height values ​​of the corresponding positions on the substrate measured by all measurement spots are obtained.

[0012] Optionally, averaging all the vertical height values ​​measured by each measuring light spot to obtain an average vertical height value of each measuring light spot;

[0013] The ideal vertical height value is obtained by taking the average of the maximum and minimum average vertical height values ​​of all measured light spots;

[0014] The average vertical height value of each measuring light spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measuring light spot.

[0015] Optionally, the number of the measurement points is at least five, and the measurement points are randomly distributed on the substrate.

[0016] Optionally, after obtaining the second position information of the corresponding position on the substrate, the method further includes:

[0017] Any one of the measurement points is selected, and the selected measurement point is sequentially moved under all the measurement spots for a third measurement, to obtain third position information of a corresponding position on the substrate measured by each measurement spot.

[0018] Optionally, the first position information, the second position information, and the third position information all include horizontal coordinate values ​​and vertical coordinate values. In the first measurement and the second measurement, each time the projection is onto the measurement point, the horizontal coordinate value and the vertical coordinate value of the corresponding position on the substrate measured by the measurement spot aligned with the measurement point are obtained.

[0019] Optionally, the tilt angle change in the horizontal direction is calculated based on the horizontal coordinate value and the vertical coordinate value measured by the measurement spot aligned with the measurement point;

[0020] Obtaining a vertical height correction value for each measuring light spot according to the tilt angle change and the horizontal coordinate value and the vertical coordinate value of each measuring light spot measured during the third measurement;

[0021] The ideal vertical height value is obtained by taking the average of the maximum and minimum vertical height correction values ​​of all measurement spots;

[0022] The vertical height correction value of each measuring light spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measuring light spot.

[0023] Optionally, the horizontal direction includes the X direction and the Y direction, and the vertical direction is the Z direction. The tilt angle changes in the X direction and the Y direction are calculated using the following formula based on the horizontal coordinate value and the vertical coordinate value measured by the measurement spot aligned with the measurement point:

[0024]

[0025] Wherein, n is the number of the measurement points, x1~x n is the X coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, y1~y n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, z1~z n is the Z coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, x n+1 ~x 2n is the X coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, and y n+1 ~y 2n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, z n+1 ~z 2nis the Z coordinate value measured by the measurement spot aligned with the measurement point during the second measurement, Z0_delta is the vertical coordinate value of the center point of the substrate, wwy is the tilt angle of the substrate in the X direction; wwx is the tilt angle of the substrate in the Y direction; szxa_delta is the change in the tilt angle of the substrate in the X direction, and szya_delta is the change in the tilt angle of the substrate in the Y direction.

[0026] Optionally, the vertical height correction value of each measuring spot is calculated according to the tilt angle change and the horizontal coordinate value and the vertical coordinate value of each measuring spot measured during the third measurement using the following formula:

[0027] z i +szxa_delta·x i +szya_delta·y i =Z i

[0028] Wherein, i is a certain measuring light spot, 1≤i≤N, N is the number of measuring light spots; x i and y i is the horizontal coordinate value measured by the measuring spot i, z i is the vertical coordinate value measured by the measuring spot i, Z i is the vertical height correction value of the measurement spot i.

[0029] Optionally, the substrate is disposed on a workpiece stage, and the workpiece stage drives the substrate to move, so that the measurement light spot is projected onto the substrate.

[0030] In a multi-spot zero deviation calibration method provided by the present invention, the first position information and the second position information obtained by the same measuring spot at the same position on the substrate will be different values. The calculation using the first position information and the second position information can offset the scanning tilt deviation and wedge deviation existing in part of the substrate, making the calibration of the zero deviation of each measuring spot more accurate; and the same measuring spot is aligned with at least four measurement points in sequence, and then the position information of the corresponding position on the substrate measured by at least one measuring spot is obtained, so that the position information of the measuring spot corresponding to at least four positions on the substrate can be obtained. The scanning tilt deviation and wedge deviation existing in the substrate can be more accurately judged based on the position information of multiple positions on the substrate, and then the scanning tilt deviation and wedge deviation existing in the substrate can be more accurately offset by calculation based on the first position information and the second position information, thereby further improving the calibration accuracy of the zero deviation of the measuring spot. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1Schematic diagram of the deviation between the zero plane of multiple measurement spots in the focusing and leveling system and any ideal plane;

[0032] Figure 2 Schematic diagram of the deviation of the zero plane of two measurement spots in the focusing and leveling system;

[0033] Figure 3 This is a flow chart of the multi-spot zero deviation calibration method provided in Example 1 of the present invention;

[0034] Figure 4 A schematic diagram of the positions of the measurement points and the measurement spots in the multi-spot zero deviation calibration method provided in the first embodiment of the present invention;

[0035] Figure 5 A schematic diagram of the distribution of measurement points of the multi-spot zero deviation calibration method provided in the second embodiment of the present invention;

[0036] Wherein, the accompanying drawings are marked as follows:

[0037] 10 - arbitrary ideal plane; 11, 22 - zero plane of the measurement spot; 20 - workpiece stage; 21 - substrate; 100, 110 - substrate; 200 - light beam; 210 - measurement spot; A, B, C, D, E - measurement points. DETAILED DESCRIPTION

[0038] The following is a more detailed description of the specific embodiments of the present invention with reference to schematic diagrams. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0039] [Example 1]

[0040] This embodiment provides a multi-spot zero deviation calibration method to improve the calibration accuracy of the multi-spot zero deviation. Figure 3 For the flowchart of the multi-spot zero deviation calibration method provided in this embodiment, please refer to Figure 3 , the multi-spot zero deviation calibration method includes:

[0041] Step S1: providing a substrate having at least four measurement points;

[0042] Step S2: The focusing and leveling system projects the same light beam onto each measurement point in sequence for a first measurement. The light beam includes at least two measurement spots. Each time the light beam is projected onto a measurement point, the same measurement spot is aligned with the measurement point, and first position information of a corresponding position on the substrate measured by at least one measurement spot is obtained.

[0043] Step S3: The substrate is rotated horizontally by 180°, and the focusing and leveling system projects the light beam onto each measurement point in sequence for a second measurement. Each time the light beam is projected onto a measurement point, the same measurement spot is aligned with the measurement point, and second position information of the corresponding position on the substrate measured by at least one measurement spot is obtained.

[0044] Step S4: Calculate the zero position deviation value of each measurement spot using the first position information and the second position information corresponding to each measurement point.

[0045] Figure 4 This is a schematic diagram of the positions of the measurement points and the measurement spots in the multi-spot zero deviation calibration method provided in this embodiment. Figure 4 The multi-spot zero deviation calibration method provided in this embodiment is described in detail.

[0046] Execute step S1: provide a substrate, wherein the substrate has at least four measurement points.

[0047] Specifically, the substrate includes, but is not limited to, a silicon wafer, a glass plate, or a ceramic plate. Any circuit pattern may be formed on the substrate. At least four measurement points are provided on the substrate. In this embodiment, the substrate has at least two measurement point groups, each of which includes at least one pair of measurement points. Specifically, the number of measurement points is an even number greater than or equal to four, and each pair of measurement points is symmetrically arranged relative to the center of the substrate. The centers of all measurement points within each measurement point group lie on the same virtual line, and the direction of the virtual line for each measurement point group can be considered a scanning tilt direction for the substrate. The virtual lines of any two measurement point groups do not overlap, meaning that the directions of the virtual lines of multiple measurement point groups correspond to multiple scanning tilt directions for the substrate.

[0048] Please refer to Figure 4 , Figure 4 Four measurement points A, B, C, and D are shown in the example. Measurement points A and B form a pair, and C and D form another pair. These two pairs of measurement points can be used to measure the scanning tilt of the substrate along the AB and CD directions. The center point of substrate 100 serves as the origin, and measurement points A, B, and C, D are symmetrically positioned relative to the center of the substrate.

[0049] Execute step S2: The focusing and leveling system projects the same light beam onto each measuring point in sequence for a first measurement. The light beam includes at least two measuring spots. Each time the light beam is projected onto a measuring point, the same measuring spot is aligned with the measuring point, and first position information of a corresponding position on the substrate measured by at least one measuring spot is obtained.

[0050] Specifically, the substrate is placed on a workpiece stage, and the focusing and leveling system projects the same light beam onto each measurement point in sequence for a first measurement. The light beam includes at least two measurement spots, and the substrate is moved by the workpiece stage so that the measurement spots are projected onto the substrate. When the same light beam is projected onto each measurement point in sequence, the same measurement spot in the light beam is aligned with each measurement point. The substrate is moved by the workpiece stage, specifically by translating the substrate along the X and Y directions, so that the same measurement spot is aligned with each measurement point in sequence. First position information is then obtained for the corresponding position on the substrate measured by at least one measurement spot. In this embodiment, after the same measurement spot is aligned with each measurement point in sequence, first position information for the corresponding positions on the substrate measured by all measurement spots is obtained. The first position information is the vertical height value of the corresponding position on the substrate measured by the measurement spot.

[0051] Please refer to Figure 4 , Figure 4 The light beam 200 in the example includes five measuring spots 210, of which four measuring spots 210 are evenly distributed around one measuring spot 210, so that the same measuring spot 210 is aligned with the measuring points A, B, C, and D in sequence. In this embodiment, the central measuring spot 210 can be aligned with the measuring points A, B, C, and D in sequence. During the alignment, the remaining four measuring spots 210 are also projected onto the substrate 100. The positions of the remaining four measuring spots 210 on the substrate 100 are the positions of the corresponding measuring points evenly distributed around the circumference. Then, the vertical height values ​​of the corresponding positions on the substrate measured by all the measuring spots 210 are obtained. When the same measuring spot is aligned with the measuring points A, B, C, and D, the vertical height values ​​of the corresponding positions on the substrate measured by the N measuring spots are set as Z 1A0 ~Z NA0 、Z 1B0 ~Z NB0 、Z 1C0 ~Z NC0 、Z 1D0 ~Z ND0 Each measurement spot measures the vertical height values ​​of the four corresponding positions on the substrate.

[0052] Execute step S3: rotate the substrate horizontally 180°, and adjust the focusing and leveling system to project the light beam onto each measurement point in turn for a second measurement. Each time the light beam is projected onto a measurement point, the same measurement spot is aligned with the measurement point, and second position information of the corresponding position on the substrate measured by at least one measurement spot is obtained.

[0053] Specifically, the substrate is rotated horizontally 180°, and the focusing and leveling system projects the light beam onto each measurement point in turn for a second measurement. The substrate is moved by the workpiece stage so that the measurement spot is projected onto the substrate. When the light beam is projected onto each measurement point in turn, the same measurement spot in the light beam is aligned with each measurement point. The substrate is moved by the workpiece stage, specifically by translating the substrate along the X and Y directions of the substrate so that the same measurement spot is aligned with each measurement point in turn, and then second position information of the corresponding position on the substrate measured by at least one measurement spot is obtained. In this embodiment, after the same measurement spot is aligned with each measurement point in turn, the second position information of the corresponding position on the substrate measured by all measurement spots is obtained. The second position information is the vertical height value of the corresponding position on the substrate measured by the measurement spot. In this embodiment, the substrate is rotated horizontally 180° while the workpiece stage remains stationary, and the substrate is directly adjusted horizontally by 180°.

[0054] Also using Figure 4 The light beam 200 in the example includes five measurement spots 210. After the substrate 100 is rotated horizontally by 180°, the central measurement spot 210 is aligned with the measurement points A, B, C, and D in sequence. During the alignment, the remaining four measurement spots 210 are also projected onto the substrate. The positions of the remaining four measurement spots 210 on the substrate 100 are evenly distributed around the corresponding measurement points. Then, the vertical height values ​​of the corresponding positions on the substrate measured by all the measurement spots 210 are obtained. After the substrate is rotated horizontally by 180°, when the same measurement spot is aligned with the measurement points A, B, C, and D, the vertical height values ​​of the corresponding positions on the substrate measured by the N measurement spots are set as Z. NA180 ~Z NA180 、Z 1B180 ~Z NB180 、Z 1C180 ~Z NC180 、Z 1D180 ~Z ND180 , each measurement spot measures the vertical height values ​​of the corresponding four positions on the substrate.

[0055] Execute step S4: calculate the zero position deviation value of each measuring light spot using the first position information and the second position information corresponding to each measuring point.

[0056] Specifically, since the first position information and the second position information are both vertical height values ​​of corresponding positions on the substrate measured by the measuring spot, the average of all vertical height values ​​measured by each measuring spot is taken to obtain the average vertical height value of each measuring spot. All vertical height values ​​measured by each measuring spot include all vertical height values ​​measured by each measuring spot in the first measurement and all vertical height values ​​measured by each measuring spot in the second measurement.

[0057] by Figure 4 Taking the number of measurement points shown in as an example, the calculation formula for the average vertical height of the measurement spot is as follows:

[0058]

[0059] in, is the average vertical height value corresponding to N measurement spots.

[0060] Furthermore, the maximum and minimum average vertical height values ​​of all measured light spots are averaged to obtain the ideal vertical height value. The calculation formula is as follows:

[0061]

[0062] in, is the maximum of the average vertical height values ​​of all measured light spots, The minimum of the average vertical height values ​​of all measured light spots, Z ref is the ideal vertical height value.

[0063] Furthermore, the average vertical height value of each measurement spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measurement spot. The calculation formula is as follows:

[0064]

[0065] Among them, Z 1delta ~Z Ndelta is the zero position deviation value of N measurement spots.

[0066] In this embodiment, if the substrate has scanning tilt deviation and wedge deviation, the two vertical height values ​​measured by each measuring spot at the same position on the substrate during the first measurement and the second measurement are different. Taking the average of the vertical height value obtained by the first measurement and the vertical height value obtained by the second measurement of each measuring spot can offset the scanning tilt deviation and first-order wedge deviation existing in part of the substrate. The ideal vertical height value is obtained by averaging the vertical height values. The zero deviation value of each measuring spot is then obtained by subtracting the average vertical height value of each measuring spot from the ideal vertical height value, thereby making the calibration of the zero deviation of each measuring spot more accurate. In addition, the same measuring spot is aligned with at least four measuring points in sequence, and then the position information of the corresponding position on the substrate measured by at least one measuring spot is obtained, so that the position information of the measuring spot corresponding to at least four positions on the substrate can be obtained. The scanning tilt deviation and the first-order wedge deviation of the substrate can be more accurately judged through the position information of multiple positions on the substrate. Then, calculation based on the first position information and the second position information can more accurately offset the scanning tilt deviation and the first-order wedge deviation of the substrate, thereby further improving the calibration accuracy of the zero position deviation of the measuring spot.

[0067] [Example 2]

[0068] Figure 5 This is a schematic diagram of the distribution of measurement points for the multi-spot zero deviation calibration method provided in this embodiment. Figure 5 , which is different from the first embodiment, is that in this embodiment, the number of measurement points E is at least five, and the measurement points E are randomly distributed on the substrate 110; in the first measurement and the second measurement, each time the measurement point is projected onto the measurement point, the horizontal coordinate value and the vertical coordinate value of the corresponding position on the substrate measured by the measurement spot aligned with the measurement point are obtained, where the horizontal coordinate value and the vertical coordinate value are the X coordinate value, Y coordinate value, and Z coordinate value corresponding to the horizontal XYZ coordinate system established with the center point of the substrate.

[0069] In this embodiment, after obtaining the second position information of the corresponding position on the substrate, the method further includes:

[0070] Select any measurement point and move the selected measurement point to all measurement spots in turn for a third measurement. Obtain the third position information of the corresponding position on the substrate measured by each measurement spot. The third position information includes horizontal and vertical coordinate values. Similarly, the horizontal and vertical coordinate values ​​are the X, Y, and Z coordinate values ​​corresponding to the horizontal XYZ coordinate system established with the center point of the substrate.

[0071] In this embodiment, the horizontal direction includes the X direction and the Y direction, and the vertical direction is the Z direction. The tilt angle changes in the X and Y directions are calculated based on the horizontal and vertical coordinate values ​​measured by the measurement spot aligned with the measurement point. The calculation formula is as follows:

[0072]

[0073] Among them, n is the number of measurement points, x1~x n The X coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, y1~y n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, z1~z n is the Z coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, x n+1 ~x 2n is the X coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, and y n+1 ~y 2n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, z n+1 ~z 2nis the Z coordinate value measured by the measurement spot aligned with the measurement point during the second measurement, Z0_delta is the vertical coordinate value of the center point of the substrate, wwy is the tilt angle of the substrate in the X direction; wwx is the tilt angle of the substrate in the Y direction; szxa_delta is the change in the tilt angle of the substrate in the X direction, and szya_delta is the change in the tilt angle of the substrate in the Y direction.

[0074] Furthermore, the vertical height correction value of each measuring spot is obtained according to the tilt angle change and the horizontal coordinate value and vertical coordinate value of each measuring spot measured during the third measurement. The calculation formula is as follows:

[0075] z i +szxa_delta·x i +szya_delta·y i =Z i

[0076] Where i is a certain measurement spot, 1≤i≤N, N is the number of measurement spots; x i and y i is the horizontal coordinate value measured by the measuring spot i, z i is the vertical coordinate value measured by the measuring spot i, Z i is the vertical height correction value of the measured light spot i.

[0077] Furthermore, the maximum and minimum vertical height correction values ​​of all measured light spots are averaged to obtain the ideal vertical height value. The calculation formula is as follows:

[0078] z ref =(z max +z min ) / 2

[0079] Among them, Z max The maximum vertical height correction value of all measurement spots, Z min The minimum of all vertical height correction values ​​of the measurement spot, Z ref is the ideal vertical height value.

[0080] Furthermore, the vertical height correction value of each measuring spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measuring spot. The calculation formula is as follows:

[0081]

[0082] Among them, Z 1delta ~Z Ndelta is the zero position deviation value of N measurement spots.

[0083] In this embodiment, the wedge deviation of the substrate is offset by the horizontal and vertical coordinate values ​​obtained from the first and second measurements, and the change in the horizontal tilt angle of the substrate is calculated. The change in the tilt angle is the change in the tilt angle of the substrate during movement. The vertical coordinate value measured by each measurement spot is corrected using the change in the tilt angle to obtain its vertical height correction value. Then, the zero deviation value of each measurement spot is calculated, thereby making the calibration of the zero deviation of each measurement spot more accurate.

[0084] In summary, in a multi-spot zero deviation calibration method provided by the present invention, at least four measuring points are provided on the provided substrate, and the focusing and leveling system projects the same light beam onto each measuring point in turn for a first measurement, and the light beam includes at least two measuring spots. Each time it is projected onto a measuring point, the same measuring spot is aligned with the measuring point, and at least one first position information of the corresponding position on the substrate measured by the measuring spot is obtained; then, the substrate is rotated horizontally 180°, and the focusing and leveling system projects the light beam onto each measuring point in turn for a second measurement, each time it is projected onto a measuring point, the same measuring spot is aligned with the measuring point, and at least one second position information of the corresponding position on the substrate measured by the measuring spot is obtained; the zero deviation value of each measuring spot is calculated using the first position information and the second position information corresponding to each measuring point. In the present invention, if the substrate has scanning tilt deviation and wedge deviation, the first position information and the second position information obtained by the same measuring spot at the same position on the substrate will be different values. The first position information and the second position information are used for calculation to offset the scanning tilt deviation and wedge deviation of part of the substrate, so that the calibration of the zero deviation of each measuring spot is more accurate; and the same measuring spot is aligned with at least four measurement points in sequence, and then the position information of the corresponding position on the substrate measured by at least one measuring spot is obtained, so that the position information of the measuring spot corresponding to at least four positions on the substrate can be obtained. The scanning tilt deviation and wedge deviation of the substrate can be more accurately judged based on the position information of multiple positions on the substrate. Then, the scanning tilt deviation and wedge deviation of the substrate can be more accurately offset by calculation based on the first position information and the second position information, thereby further improving the calibration accuracy of the zero deviation of the measuring spot.

[0085] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any person skilled in the art who, without departing from the scope of the present invention, makes any equivalent substitution, modification, or other changes to the technical solution and technical content disclosed in the present invention shall be deemed to be within the scope of the present invention and still fall within the scope of protection of the present invention.

Claims

1. A multi-spot zero deviation calibration method, characterized in that: include: providing a substrate having at least four measurement points thereon; The focusing and leveling system projects the same light beam onto each of the measurement points in sequence for a first measurement, wherein the light beam includes at least two measurement spots. Each time the light beam is projected onto the measurement point, the same measurement spot is aligned with the measurement point, and first position information of a corresponding position on the substrate measured by at least one measurement spot is obtained. The substrate is horizontally rotated 180 degrees, and the focusing and leveling system projects the light beam onto each of the measurement points in sequence for a second measurement, wherein each time the light beam is projected onto the measurement point, the same measurement spot is aligned with the measurement point, and second position information of a corresponding position on the substrate measured by at least one measurement spot is obtained; The zero position deviation value of each measuring light spot is calculated using the first position information and the second position information corresponding to each measuring point.

2. The multi-spot zero deviation calibration method according to claim 1, characterized in that: The substrate has at least two measurement point groups, each of the measurement point groups includes at least one pair of measurement points, each pair of measurement points is symmetrically arranged relative to the center of the substrate, the centers of all measurement points in each measurement point group are located on the same virtual line, and the virtual lines of any two measurement point groups do not overlap.

3. The multi-spot zero deviation calibration method according to claim 1, characterized in that: The first position information and the second position information are both vertical height values. In the first measurement and the second measurement, each time the projection is onto the measurement point, the vertical height values ​​of the corresponding positions on the substrate measured by all measurement spots are obtained.

4. The multi-spot zero deviation calibration method according to claim 3, characterized in that: averaging all the vertical height values ​​measured by each measuring light spot to obtain an average vertical height value of each measuring light spot; The ideal vertical height value is obtained by taking the average of the maximum and minimum average vertical height values ​​of all measured light spots; The average vertical height value of each measuring light spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measuring light spot.

5. The multi-spot zero deviation calibration method according to claim 1, characterized in that: The number of the measurement points is at least five, and the measurement points are randomly distributed on the substrate.

6. The multi-spot zero deviation calibration method according to claim 1, wherein: After obtaining the second position information of the corresponding position on the substrate, the method further includes: Any one of the measurement points is selected, and the selected measurement point is sequentially moved under all the measurement spots for a third measurement, to obtain third position information of a corresponding position on the substrate measured by each measurement spot.

7. The multi-spot zero deviation calibration method according to claim 6, characterized in that: The first position information, the second position information, and the third position information all include horizontal coordinate values ​​and vertical coordinate values. In the first measurement and the second measurement, each time the projection is onto the measurement point, the horizontal coordinate value and the vertical coordinate value of the corresponding position on the substrate measured by the measurement spot aligned with the measurement point are obtained.

8. The multi-spot zero deviation calibration method according to claim 7, characterized in that: Calculating a change in the tilt angle in the horizontal direction based on the horizontal coordinate value and the vertical coordinate value measured by the measuring light spot aligned with the measuring point; Obtaining a vertical height correction value for each measuring light spot according to the tilt angle change and the horizontal coordinate value and the vertical coordinate value of each measuring light spot measured during the third measurement; The ideal vertical height value is obtained by taking the average of the maximum and minimum vertical height correction values ​​of all measurement spots; The vertical height correction value of each measuring light spot is subtracted from the ideal vertical height value to obtain the zero position deviation value of each measuring light spot.

9. The multi-spot zero deviation calibration method according to claim 8, characterized in that: The horizontal direction includes the X direction and the Y direction, and the vertical direction is the Z direction. The tilt angle changes in the X and Y directions are calculated using the following formulas based on the horizontal and vertical coordinate values ​​measured by the measurement spot aligned with the measurement point: Wherein, n is the number of the measurement points, x1~x n is the X coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, y1~y n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, z1~z n is the Z coordinate value measured by the measuring spot aligned with the measuring point during the first measurement, x n+1 ~x 2n is the X coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, and y n+1 ~y 2n is the Y coordinate value measured by the measuring spot aligned with the measuring point during the second measurement, z n+1 ~z 2n is the Z coordinate value measured by the measurement spot aligned with the measurement point during the second measurement, Z0_delta is the vertical coordinate value of the center point of the substrate, wwy is the tilt angle of the substrate in the X direction; wwx is the tilt angle of the substrate in the Y direction; szxa_delta is the change in the tilt angle of the substrate in the X direction, and szya_delta is the change in the tilt angle of the substrate in the Y direction.

10. The multi-spot zero deviation calibration method according to claim 9, characterized in that: The vertical height correction value of each measuring light spot is calculated according to the tilt angle change and the horizontal coordinate value and the vertical coordinate value of each measuring light spot measured during the third measurement using the following formula: With i +szxa_delta x i +neck_delta·y i =Z i Wherein, i is a certain measuring light spot, 1≤i≤N, N is the number of measuring light spots; x i and y i is the horizontal coordinate value measured by the measuring spot i, z i is the vertical coordinate value measured by the measuring spot i, Z i is the vertical height correction value of the measurement spot i.

11. The multi-spot zero deviation calibration method according to claim 1, wherein: The substrate is placed on a workpiece stage, and the workpiece stage drives the substrate to move, so that the measuring light spot is projected onto the substrate.

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