Error compensation method and device for motion platform

Abstract

The invention relates to an error compensation method and device for a motion table, and the method comprises the steps: adjusting the displacement of the motion table moving to each first position based on a first compensation table in a process of controlling the motion table to move so as to detect a first to-be-detected workpiece, the first compensation table comprises a first displacement compensation amount needing to be adjusted when the moving table moves to each first position; determining a current residual table based on a detection position and a theoretical position of a first feature point on the first to-be-detected workpiece in the detection process, wherein the current residual table comprises second displacement compensation amounts needing to be adjusted when the motion table moves to each second position; and determining a second compensation table based on the first compensation table and the current residual table, wherein the second compensation table comprises a third displacement compensation amount which needs to be adjusted when the moving table moves to each third position. According to the method, the residual error is used for further compensating the error, a denser error compensation table can be generated, and the dynamic correction capability of the semiconductor detection equipment on the displacement error of the motion table is remarkably improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to an error compensation method and apparatus for a motion table. Background Technology

[0002] Semiconductor inspection equipment detects defects on wafers to reflect problems in the wafer manufacturing process. To accurately assess defects, it is necessary to accurately locate the imaging position and provide accurate defect coordinates. Since semiconductor inspection equipment often uses a high-speed stage to move the wafer under the imaging system for imaging, and relies on the stage to achieve wafer alignment, imaging position positioning, and defect coordinate calculation, positioning errors of the stage will cause alignment errors and defect coordinate offsets.

[0003] Currently, to address the positioning error of the motion stage, most related technologies employ the method of averaging multiple measurements to obtain the error, without considering the residual error that may still exist after actual compensation. Furthermore, since the sparse sampling used in these technologies can only collect a small number of points within the motion range, when there are sudden changes in local error in the gaps between sampling points, sparse sampling will be unable to measure this error and thus cannot compensate for it, resulting in residual errors still existing when these gaps are actually scanned. Summary of the Invention

[0004] This application discloses an error compensation method and apparatus for a motion table, which is used to solve the technical problem of residual error in the motion table.

[0005] In a first aspect, this application provides an error compensation method for a motion table, wherein the motion table is used to carry a first workpiece to be tested and a second workpiece to be tested. The method includes: during the process of controlling the motion table to move to detect the first workpiece to be tested, adjusting the displacement of the motion table to each first position based on a first compensation table, wherein the first compensation table includes a first displacement compensation amount required for the motion table to move to each first position; determining a current residual table based on the detection position and theoretical position of a first feature point on the first workpiece to be tested during the detection process, wherein the current residual table includes a second displacement compensation amount required for the motion table to move to each second position; determining a second compensation table based on the first compensation table and the current residual table, wherein the second compensation table includes a third displacement compensation amount required for the motion table to move to each third position, wherein the second compensation table is used as a first compensation table for detecting the second workpiece to be tested, and the third position is determined based on the first position and the second position.

[0006] Thus, in the process of controlling the movement of the motion stage to inspect the first workpiece to be tested carried by the motion stage in the semiconductor testing equipment, this application adjusts the displacement of the motion stage to each first position based on a first compensation table. The first compensation table includes the first displacement compensation amount required to adjust the motion stage to each first position. Using the first compensation table can solve the systematic error of the motion stage. Based on the detection position and theoretical position of the first feature point on the first workpiece to be tested during the testing process, a current residual table is determined. The current residual table includes the second displacement compensation amount required to adjust the motion stage to each second position. Through the online testing process, the residual error after the initial compensation is accurately captured, and the non-systematic error of the semiconductor testing equipment in the current state is reflected in real time. The second residual table is determined based on the first compensation table and the current residual table. The compensation table, specifically the second compensation table, includes the third displacement compensation amount required for the motion table to move to each third position. This second compensation table is used for the first compensation table, which is used to inspect the second workpiece to be tested, carried by the motion table. The second compensation table not only includes the original systematic error compensation (i.e., the first compensation table) but also incorporates the dynamic residual error correction amount during the actual inspection process. This helps improve the displacement control accuracy of the second workpiece to be tested, thereby improving the defect detection accuracy. Furthermore, the third position is determined based on the first and second positions, meaning that the coverage of the second compensation table integrates the key positions of the initial design with the actual inspection positions. This composite position sampling strategy can significantly improve the compensation accuracy for error-sensitive positions such as workpiece edges and feature-dense areas.

[0007] In one possible implementation, the method for generating the first compensation table includes: clearing the historical compensation parameters of the motion stage controller; controlling the motion stage to move to perform multiple rounds of scanning measurements on a standard calibration workpiece mounted thereon; in each round, determining the motion stage error based on the deviation between the actual and theoretical positions of the second feature points obtained by scanning; generating compensation parameters for that round based on the motion stage error and sending them to the motion stage controller; iteratively executing multiple rounds of scanning and compensation until the motion stage residual calculated based on the compensation parameters tends to stabilize, and organizing the finally determined compensation parameters to form the first compensation table.

[0008] In this way, this application provides a high-precision benchmark model for subsequent error compensation through a calibration mechanism of "multi-round scanning-dynamic feedback-iterative convergence". It not only eliminates accumulated deviations by clearing historical compensation parameters, but also generates compensation parameters based on the deviation between the actual and theoretical positions of feature points in each round of multi-round scanning using standard calibration workpieces. This can detect the systematic error of the motion table. Furthermore, it updates the compensation parameters by detecting the residual error of the motion table after error compensation, which can make the compensation as accurate as possible and the residual as small as possible, thereby improving the positioning accuracy of the motion table.

[0009] In one possible implementation, the method for generating new compensation parameters in each round includes: superimposing the motion table residual measured in the current round with the compensation parameters issued for each round to obtain the true error of the motion table; and generating new compensation parameters based on the true error.

[0010] In this way, by superimposing the residuals obtained from each round of measurement with the compensation parameters issued for each round, the accuracy bottleneck of traditional single-round error compensation is broken, and the accuracy and robustness of motion table positioning compensation are significantly improved.

[0011] In one possible implementation, the method for measuring the motion table residual includes: after the motion table moves according to the currently issued compensation parameters, scanning the second feature point on the standard calibration workpiece again; calculating the actual position of the second feature point for remeasurement using a template matching algorithm; calculating the deviation between the actual position and the theoretical position for remeasurement, and determining the deviation as the motion table residual for the current cycle.

[0012] In this way, by combining template matching algorithm with feature point depth, a high-precision measurement method of "image recognition - pixel-level positioning - deviation calculation" is constructed, which can significantly improve the positioning accuracy of feature points and ensure the accuracy of residual calculation.

[0013] In one possible implementation, determining the current residual table based on the detection position and theoretical position of the first feature point on the first workpiece under test during the detection process includes: during the process of controlling the movement of the motion table to detect the first workpiece under test, when the motion table moves to a preset second position, acquiring an image of the first feature point on the first workpiece under test; determining the detection position of the first feature point through image recognition based on the image and a pre-stored template image; calculating the positional deviation between the detection position and the corresponding theoretical position; and forming the current residual table based on the positional deviation corresponding to each second position.

[0014] In this way, by triggering residual measurement in real time during the first workpiece inspection process, the pain point of not considering residual error in the traditional solution is solved. The high-precision positioning method based on image recognition can ensure the accuracy of residual quantification. This error measurement method of "real-time image recognition - feature point positioning - deviation quantification" not only realizes the real-time capture of residual error, but also ensures the measurement accuracy of the compensation basis, providing high-quality data input for the subsequent iterative optimization of the second compensation table.

[0015] In one possible implementation, determining the detection location of the first feature point by image recognition based on the image and a pre-stored template image includes: using a template matching algorithm to perform sliding matching of the pre-stored template image in the acquired image; calculating the similarity between the template image and each candidate region in the acquired image; and determining the location of the candidate region with the highest similarity as the detection location of the first feature point.

[0016] In this way, the template matching algorithm achieves accurate positioning of the first feature point detection location, and combines the global search capability of sliding matching with the local discrimination capability of similarity quantification to form a two-layer recognition mechanism of "coarse positioning-fine screening", which provides reliable feature point location data for residual calculation in semiconductor detection.

[0017] In one possible implementation, determining the second compensation table based on the first compensation table and the current residual table includes: determining a target location set, wherein the location density of the target location set is greater than or equal to the location densities of the first location and the second location; obtaining a first set of target compensation values ​​of the first compensation table on the target location set; and obtaining a second set of target compensation values ​​of the current residual table on the target location set; and generating a third displacement compensation amount of the second compensation table on the target location set through data fusion based on the first set of target compensation values ​​and the second set of target compensation values.

[0018] In this way, by constructing a target position set with a higher position density than the first and second positions, the spatial resolution of the compensation table can be improved. In particular, the compensation accuracy of error-sensitive positions such as workpiece edges and feature-dense areas is significantly improved. At the same time, by fusing the first compensation table, which reflects the systematic error of the semiconductor testing equipment, and the current residual table, which reflects the dynamic residual of the semiconductor testing equipment, through a multi-source data fusion algorithm, a second compensation table is obtained. This method has a closed-loop capability of "detection-feedback-evolution", which changes the industry practice of semiconductor testing equipment relying on periodic shutdown calibration.

[0019] In one possible implementation, determining a target location set includes: calculating the greatest common divisor of the sampling intervals of the first location and the sampling intervals of the second location; and generating a target location set with a denser sampling interval based on the greatest common divisor.

[0020] In this way, by determining the target position set whose position density is greater than or equal to that of the first and second positions, the third displacement compensation amount generated on the target position set can solve the problem that traditional fixed-interval sampling is prone to missing key errors due to sparse sampling points. Furthermore, the generated second compensation table can retain the systematic error compensation amount of the first compensation table and also cover the dynamic error correction amount of the current residual table, avoiding the loss of compensation information and improving the compensation accuracy.

[0021] In one possible implementation, obtaining the first set of target compensation values ​​of the first compensation table on the target position set includes: using an interpolation algorithm to calculate the first set of target compensation values ​​for each position in the target position set based on the first position and its corresponding first displacement compensation amount; obtaining the second set of target compensation values ​​of the current residual table on the target position set includes: using the interpolation algorithm to calculate the second set of target compensation values ​​for each target position in the target position set based on the second position and its corresponding second displacement compensation amount.

[0022] In this way, by interpolating the first compensation table and the current residual table, mathematical modeling can be used to fill the error gaps between discrete sampling points, which helps to improve the error compensation accuracy of the motion stage of the semiconductor testing equipment.

[0023] In one possible implementation, the interpolation algorithm is any one of bilinear interpolation, nearest neighbor interpolation, or cubic convolution interpolation.

[0024] In this way, by using bilinear interpolation, nearest neighbor interpolation, and cubic convolution interpolation, discrete compensation data can be transformed into a continuous spatial model, which helps to improve the error compensation accuracy and comprehensiveness of the motion stage of semiconductor testing equipment.

[0025] In one possible implementation, the data fusion uses a Kalman filter algorithm, or the data fusion method is direct superposition.

[0026] In this way, the use of the Kalman filter algorithm, which separates error and noise through mathematical modeling, during the data fusion process makes the generated new compensation value more realistic and accurate, eliminates the influence of single abnormal fluctuations, and helps to achieve high-precision data fusion, which is suitable for semiconductor testing scenarios with high precision requirements.

[0027] In one possible implementation, after inspecting the second workpiece to be tested, the method further includes: updating the current residual table based on the inspection of the second workpiece to be tested; determining a third compensation table for inspecting a third workpiece to be tested based on the second compensation table and the updated current residual table; and repeating this process in different workpieces to be tested to adaptively iteratively update the error compensation table.

[0028] In this way, by measuring residual error while performing defect detection, the error of the motion table during actual operation can be obtained, so as to correct the error difference between actual operation and calibration, achieve long-term error tracking and maintain long-term detection accuracy, and perform adaptive iterative updates based on the compensation results of different workpieces to be tested, so as to obtain a more dense and comprehensive error compensation table and improve the adaptability of complex workpiece detection.

[0029] In one possible implementation, the first feature point is a pattern that appears periodically on a wafer or mask and is capable of image recognition and template matching.

[0030] In this way, by using the first feature point located on the first workpiece to be tested for error measurement, it is not necessary to make a special calibration workpiece for error compensation. This allows the residual measurement to be completed directly in the wafer inspection process, i.e., on the corresponding production line of the semiconductor equipment, without the need to switch workpieces or adjust the inspection process, thus simplifying the error detection and compensation process.

[0031] Secondly, this application provides an error compensation device for a motion table, the motion table being used to carry a first workpiece to be tested and a second workpiece to be tested. The device includes: a motion adjustment module, used to adjust the displacement of the motion table to each first position based on a first compensation table during the process of controlling the motion table to move to detect the first workpiece to be tested, the first compensation table including a first displacement compensation amount required for the motion table to move to each first position; a residual determination module, used to determine a current residual table based on the detection position and theoretical position of a first feature point on the first workpiece to be tested during the detection process, the current residual table including a second displacement compensation amount required for the motion table to move to each second position; and a compensation determination module, used to determine a second compensation table based on the first compensation table and the current residual table, the second compensation table including a third displacement compensation amount required for the motion table to move to each third position, the second compensation table being used as a first compensation table for detecting the second workpiece to be tested, the third position being determined based on the first position and the second position.

[0032] In one possible implementation, the device includes a first compensation table generation module, configured to: clear the historical compensation parameters of the motion stage controller; control the motion stage to move to perform multiple rounds of scanning measurements on a standard calibration workpiece mounted thereon; in each round, determine the motion stage error based on the deviation between the actual and theoretical positions of the second feature points obtained by scanning; generate compensation parameters for that round based on the motion stage error and send them to the motion stage controller; iteratively execute multiple rounds of scanning and compensation until the motion stage residual calculated based on the compensation parameters tends to stabilize, and organize the finally determined compensation parameters into the first compensation table.

[0033] In one possible implementation, the device includes a compensation parameter generation module, configured to: superimpose the motion table residual measured in the current round with the compensation parameters issued for each round to obtain the true error of the motion table; and generate new compensation parameters based on the true error.

[0034] In one possible implementation, the device includes a motion table residual measurement module, configured to: scan the second feature point on the standard calibration workpiece again after the motion table moves according to the currently issued compensation parameters; calculate the actual position of the second feature point after remeasurement using a template matching algorithm; calculate the deviation between the actual position and the theoretical position after remeasurement, and determine the deviation as the motion table residual for the current cycle.

[0035] In one possible implementation, the residual determination module includes: an image acquisition module, configured to acquire an image of a first feature point on the first workpiece under test when the motion table moves to a preset second position during the process of controlling the motion table to move and detect the first workpiece under test; an image recognition module, configured to determine the detection position of the first feature point by image recognition based on the image and a pre-stored template image; and calculate the positional deviation between the detection position and the corresponding theoretical position; and a residual formation module, configured to form the current residual table based on the positional deviation corresponding to each second position.

[0036] In one possible implementation, the image recognition module includes: a sliding matching module, used to perform sliding matching of the pre-stored template image in the acquired image using a template matching algorithm; a similarity calculation module, used to calculate the similarity between the template image and each candidate region in the acquired image; and a detection module, used to determine the position of the candidate region with the highest similarity as the detection position of the first feature point.

[0037] In one possible implementation, the compensation determination module includes: a set determination module, configured to determine a target location set, wherein the location density of the target location set is greater than or equal to the location densities of the first location and the second location; a compensation value determination module, configured to obtain a first set of target compensation values ​​of the first compensation table on the target location set, and to obtain a second set of target compensation values ​​of the current residual table on the target location set; and a generation module, configured to generate a third displacement compensation amount of the second compensation table on the target location set through data fusion based on the first set of target compensation values ​​and the second set of target compensation values.

[0038] In one possible implementation, the set determination module includes a first submodule for: calculating the greatest common divisor of the sampling interval of the first position and the sampling interval of the second position; and generating a set of the target positions with a denser sampling interval based on the greatest common divisor.

[0039] In one possible implementation, the compensation value determination module includes a first interpolation module, configured to: use an interpolation algorithm to calculate a first set of target compensation values ​​for each position in the target position set based on the first position and its corresponding first displacement compensation amount; the compensation value determination module further includes a second interpolation module, configured to: use the interpolation algorithm to calculate a second set of target compensation values ​​for each target position in the target position set based on the second position and its corresponding second displacement compensation amount.

[0040] In one possible implementation, the interpolation algorithm is any one of bilinear interpolation, nearest neighbor interpolation, or cubic convolution interpolation.

[0041] In one possible implementation, the data fusion uses a Kalman filter algorithm, or the data fusion method is direct superposition.

[0042] In one possible implementation, after inspecting the second workpiece to be tested, the apparatus further includes an update module for: updating the current residual table based on the inspection of the second workpiece to be tested; determining a third compensation table for inspecting the third workpiece to be tested based on the second compensation table and the updated current residual table; and repeating this process in different workpieces to be tested to adaptively iteratively update the error compensation table.

[0043] In one possible implementation, the first feature point is a pattern that appears periodically on a wafer or mask and is capable of image recognition and template matching.

[0044] Thirdly, this application provides an error compensation device, including a memory, a plurality of processors, and a computer program stored in the memory, wherein one of the plurality of processors executes the computer program to implement the steps of the above method.

[0045] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the architecture of a semiconductor testing device provided in an embodiment of this application;

[0048] Figure 2 This is another schematic diagram of the architecture of the semiconductor testing device provided in the embodiments of this application;

[0049] Figure 3 A flowchart illustrating the error compensation method provided in an embodiment of this application;

[0050] Figure 4 A schematic diagram of a first compensation table provided for an embodiment of this application;

[0051] Figure 5 A schematic diagram of the residual error at each first position provided in the embodiments of this application;

[0052] Figure 6 A schematic diagram illustrating the new compensation parameters provided in the embodiments of this application;

[0053] Figure 7 A schematic diagram of a current residual table provided for an embodiment of this application;

[0054] Figure 8 A schematic diagram of the reference compensation amount in a first compensation table provided for embodiments of this application;

[0055] Figure 9 A schematic diagram of a second compensation table provided for an embodiment of this application;

[0056] Figure 10 A schematic diagram of an interpolated first compensation table provided for an embodiment of this application;

[0057] Figure 11 A schematic diagram of an interpolated current residual table provided for an embodiment of this application;

[0058] Figure 12 A schematic diagram of a second compensation table obtained by directly superimposing and interpolating a first compensation table and the current residual table, as provided in an embodiment of this application;

[0059] Figure 13 A schematic diagram of a portion of the target sampling space corresponding to a second compensation table provided in an embodiment of this application;

[0060] Figure 14 This is a schematic diagram of another interpolated current residual table provided for an embodiment of this application.

[0061] Explanation of reference numerals in the attached figures:

[0062] 1a-Motion table; 1b-Image acquisition device; 1c-Processor; 1d-Controller; 1e-Terminal device. Detailed Implementation

[0063] To facilitate understanding of the technical solutions provided in the embodiments of this application by those skilled in the art, the technical environment for implementing the technical solutions will be described below.

[0064] This application can be applied to wafer or mask defect detection scenarios. In these scenarios, defects on wafers are detected using semiconductor inspection equipment to reflect problems in the wafer manufacturing process. To accurately assess defects, the defect inspection equipment needs to be able to accurately locate the imaging position and provide accurate defect coordinates. Semiconductor inspection equipment often uses a high-speed stage to move the wafer under the imaging system for imaging. The stage is relied upon to achieve wafer alignment, imaging position positioning, and subsequent defect coordinate calculation. Therefore, positioning errors of the stage can cause alignment errors and defect coordinate offsets.

[0065] To address positioning errors in the motion stage, some solutions obtain a positioning error index by measuring the actual positioning information of the wafer inspection stage. Based on the mechanical structure data and working environment data of the wafer inspection stage, a design error index and a working condition error correction coefficient are obtained. Then, combining these three indices, a positioning error compensation index is derived. Positioning error compensation is then applied to the target wafer inspection stage based on this index, finally yielding an error compensation effect index for evaluation and adjustment. While this solution compensates for positioning errors, it does not correct residual errors. Since there may be a non-linear relationship between the compensation effect and the error value, using directly measured error values ​​for compensation may not fully compensate for the error. Furthermore, this solution does not measure errors during online operation, failing to eliminate the difference between offline calibration errors and actual operating errors. Residual errors may still exist during online operation, and long-term use of the same compensation parameters will fail to detect and correct changes in motion stage errors in a timely manner, potentially leading to residual errors during actual scanning. Additionally, this solution does not address the error problem in the gap area between sampling points.

[0066] Another approach uses a mask on a mask stage to expose a substrate on a motion stage. The mask has X- and Y-axis motion stage positioning error measurement marks. The motion stage or mask stage is moved step-by-step, exposing a series of imaging marks on the substrate. After development, the imaging marks on the substrate are observed using an alignment device to measure the positioning errors of the mask stage and motion stage. Data processing then yields a positioning error compensation table, which is used to perform feedforward compensation on the motion stage control system and the mask stage control system, enabling online compensation and offline calibration. While this approach compensates for positioning errors, it does not correct residual errors after compensation, nor does it address the error problem in the gap region between sampling points.

[0067] In general, current technologies for addressing positioning errors in motion stages mostly obtain the error through a single scan or by taking a statistical average of multiple measurements. However, they fail to consider the actual compensation effect and the residual error that may still exist after compensation. Alternatively, they may use offline calibration and compensation without modification, failing to measure online error and thus unable to eliminate the difference between offline calibration and actual operating errors. This leads to the continued use of the same compensation parameters for motion stage error compensation, which cannot promptly detect and correct changes in motion stage error, resulting in residual errors during actual scanning. Furthermore, offline single or a few measurement methods can only sparsely sample a small number of points within the motion range. The error in the gaps between sampling points can usually only be approximated by linear interpolation based on the sampling point error value or the error values ​​of surrounding points. This estimated error is highly likely to differ from the true error, especially when there are sudden changes in local error in the gap areas. Sparse sampling will fail to measure this error and therefore cannot compensate for it. Consequently, even with error compensation, residual errors may still exist when the motion stage moves into these gap areas.

[0068] To address the aforementioned technical problems, this application provides an error compensation method for a motion stage. During the process of controlling the movement of the motion stage to inspect a first workpiece to be tested carried by the motion stage in a semiconductor testing device, the displacement of the motion stage to each first position is adjusted based on a first compensation table. The first compensation table includes the first displacement compensation amount required to adjust the motion stage to each first position. Using the first compensation table can resolve the systematic error of the motion stage. Based on the detection position and theoretical position of the first feature point on the first workpiece to be tested during the testing process, a current residual table is determined. The current residual table includes the second displacement compensation amount required to adjust the motion stage to each second position. Through the online testing process, the residual error after initial compensation is accurately captured, reflecting the non-systematic error of the semiconductor testing device in the current state in real time. Based on the first... The compensation table and the current residual table determine the second compensation table. The second compensation table includes the third displacement compensation amount required to adjust the motion table to each third position. The second compensation table is used as the first compensation table for detecting the second workpiece to be tested carried by the motion table. The second compensation table not only includes the original systematic error compensation (i.e., the first compensation table) but also integrates the dynamic residual error correction amount in the actual detection process. This helps to improve the displacement control accuracy of the second workpiece to be tested, thereby improving the defect detection accuracy of the second workpiece to be tested. Furthermore, the third position is determined based on the first and second positions, which means that the coverage of the second compensation table integrates the key positions of the initial design and the detection positions in the actual detection. This composite position sampling strategy can significantly improve the compensation accuracy of error-sensitive positions such as workpiece edges and feature-dense areas.

[0069] This application uses a wafer defect location scenario during wafer fabrication as an example for illustration. For ease of understanding, this application first describes the architecture of the semiconductor inspection equipment. For example... Figure 1 As shown, the aforementioned semiconductor inspection equipment may include a motion stage 1a, an image acquisition device 1b, and a terminal device 1e. The terminal device 1e can interact with the devices in the semiconductor inspection equipment, such as the motion stage 1a and the image acquisition device 1b. The motion stage 1a can be used to carry a first workpiece to be tested, a second workpiece to be tested, a third workpiece to be tested, and a standard calibration workpiece; these workpieces can be wafers or photomasks. It is understood that the terminal device 1e can be a tablet, computer, or other device that can store and call program code to execute error compensation methods; the specific device can be determined according to the actual application scenario and is not limited here.

[0070] For ease of understanding, please refer to the following: Figure 2The aforementioned semiconductor testing equipment may include a motion stage 1a, an image acquisition device 1b, a processor 1c, and a controller 1d. Optionally, the processor 1c and controller 1d may be integrated into a functional module of the terminal device 1e, which can be determined according to the actual application scenario and is not limited here. For example, the aforementioned semiconductor testing equipment may include a motion stage 1a, an image acquisition device 1b, and a terminal device 1e. The terminal device 1e has a built-in microprocessor, which is used to execute the implementation method executed by the processor 1c. The terminal device 1e may also have a built-in controller 1d to receive parameters sent by the processor 1c and generate a new compensation table to control the motion stage 1a and other devices. The controller 1d may be a motion controller or other types of controllers. This application embodiment does not limit this, and only uses a motion controller as an example for explanation.

[0071] The aforementioned motion stage 1a can be an X / Y / Theta axis motion stage 1a, or it can be any other movable wafer motion stage 1a. This application embodiment does not limit this; only an X / Y / Theta axis motion stage 1a is used as an example for illustration. It is understood that the aforementioned motion stage 1a can move along the X-axis, Y-axis, and Theta axis, corresponding to lateral movement, longitudinal movement, and rotational angle movement, respectively. The aforementioned motion stage 1a can be used to load wafers and adjust their positions through movement. Wafers loaded on the motion stage 1a can undergo wafer alignment operations. Wafer alignment can be achieved by using an optical microscope to locate periodic feature patterns on the wafer, adjusting the wafer's rotation angle to align it, and determining the wafer's position.

[0072] The image acquisition device 1b described above can be a line scan camera or other device capable of acquiring real-time images of the wafer. This application does not limit this; only a line scan camera is used as an example for explanation. The line scan camera can scan the wafer and acquire workpiece images. The processor 1c described above can be connected to a memory (not shown in the figure). The memory can store programs, workpiece images obtained from the image acquisition device 1b, data obtained after processing by the processor, etc. The processor can process the workpiece images through the programs stored in the memory. The processor 1c can also send data to the controller 1d, such as a first compensation table. The controller 1d can receive the data sent by the processor 1c and send instructions to the motion stage 1a according to the data. The instructions may include, but are not limited to, motion control instructions. The motion control instructions can trigger the motion stage 1a to move according to the motion control instructions.

[0073] To facilitate understanding of the application of the semiconductor testing equipment in the error compensation method, this application embodiment uses the terminal device in the semiconductor testing equipment as the execution subject to illustrate the error compensation method. The terminal device can be a device that integrates functional modules such as processor, controller, and memory.

[0074] like Figure 3 As shown, the error compensation method may include the following steps S101 to S103.

[0075] In step S101, during the process of controlling the movement of the motion table to detect the first workpiece to be tested, the displacement of the motion table to each first position is adjusted based on the first compensation table.

[0076] Before executing step S101, the first workpiece to be tested needs to be uploaded to the motion table and positioned. The terminal device also needs to load the first compensation table into the motion table controller, ensuring that the motion table controlled by the motion table controller performs motion compensation based on the first compensation table during subsequent movements. The first compensation table includes the first displacement compensation amount required for the motion table to move to each first position. In fact, the first compensation table is a mapping table containing the first displacement compensation amount required for each first position the motion table needs to move to. This compensation amount includes the compensation value in the X direction and the compensation value in the Y direction under a preset coordinate system. The terminal device can control the motion table to move to a certain first position through the motion table controller. However, due to the positioning error of the motion table, the position of the motion table after completing the predetermined displacement is not the first position. At this time, it is necessary to control the motion table to adjust an additional displacement amount before the motion table is truly in the first position. This additional displacement adjustment is the first displacement compensation amount. Specifically, the first compensation table includes the amount of movement along the X-axis and the amount of movement along the Y-axis under a preset coordinate system.

[0077] The terminal device can control the motion stage to move according to the motion control logic shown in steps S1 to S4 below to detect each of the first feature points of the first workpiece to be tested. In step S1, the motion stage controller receives an instruction from the terminal device to move to the theoretical position P. In step S2, the motion stage controller obtains the compensation amount corresponding to the theoretical position P by querying the first compensation table, and determines the actual target position of the motion stage as P' = theoretical position P + the compensation amount corresponding to the theoretical position P. In step S3, the motion stage controller controls the motion stage to move to the target position P'. In step S4, after the motion stage stabilizes, the image acquisition device 1b acquires the image at the first feature point to detect the target position.

[0078] Each first position refers to the location of the graphic marker (i.e., the second feature point) of the standard calibration workpiece described in the following embodiments. The sampling space in which each first position is located can be called the first sampling space. The size of the first sampling space can be flexibly set according to actual needs, but the first sampling space needs to include at least the positions of all the second feature points on the standard calibration workpiece, and the coordinates of each first position in the first sampling space can also be flexibly set according to actual conditions. For example Figure 4As shown, the first sampling space is within the range of [0, 300] in both the x and y axes, and the sampling interval at the first position is 75. The terminal device can obtain the positional error of the sampling motion stage by sampling the positioning error of the motion stage. Figure 4 The first displacement compensation values ​​for 25 first positions in the first sampling space are shown. The coordinates of these 25 first positions include (0,0), (0,75), (75,0), (150,0), (75,300), etc. See details. Figure 4 .by Figure 4 Taking the first displacement compensation amount A1=1.6 as an example, 1.6 represents the additional displacement adjustment required in the x-axis and y-axis directions when the motion table moves to the first position (75, 300). In fact, the first compensation table can be regarded as multiple coordinate-error pairs. Each coordinate represents the first position (x', y'), and the error corresponding to that coordinate represents the first displacement compensation amount (△x1, △y1) corresponding to (x', y'). This means that when the motion table moves to the first position, it actually needs to move x'+△x1 in the x-axis and y'+△y1 in the y-axis.

[0079] The first compensation table can be a preset compensation table, and the compensation values ​​in the table can be pre-stored in the terminal device. Alternatively, the first compensation table can also be obtained by detecting a standard calibration workpiece. The method for generating the first compensation table includes: clearing the historical compensation parameters of the motion table controller, for example, the terminal device can send a command to the motion table controller via the host computer to reset the historical parameters such as the compensation table stored in the motion table controller to zero or set them to the default state; controlling the movement of the motion table, for example, the terminal device can control the motion table to move along a predetermined path via the motion table controller, stopping at the positions of each second feature point on the standard calibration workpiece. After the motion table stabilizes, the terminal device controls the image acquisition device 1b to sequentially acquire the images of each second feature point to determine the actual / measured position of each second feature point. Thus, the standard calibration workpiece carried on the motion table is scanned and measured multiple times according to this motion control process. The standard calibration workpiece has a sufficient number of easily identifiable known second feature points with periodic distributions pre-set on it, and the theoretical positions of the second feature points have been accurately measured and stored in the terminal device in advance. Through each round of scanning... The tracing measurement can obtain the actual position of the second feature point in the standard calibration workpiece. In each round, based on the deviation between the actual position and the theoretical position of the second feature point obtained by scanning, the motion table error of that round is determined. For each second feature point, the corresponding deviation can be calculated by the deviation ΔX in the X direction = actual X coordinate - theoretical X coordinate, and the deviation ΔY in the Y direction = actual Y coordinate - theoretical Y coordinate. For example, if the actual position of a second feature point is (73.4, 298.4) and the theoretical position is (75, 300), then the corresponding deviation can be calculated as (-1.6, -1.6). The motion table error of each round refers to the collected deviation data (ΔX, ΔY) of all second feature points in this round. Based on the motion table error, the compensation parameters for that round are generated and sent to the motion table controller. For example, if the deviation is (-1.6, -1.6), the corresponding compensation parameter is (1.6, 1).6) After the terminal device sends the compensation parameters for this round to the motion table controller, the motion table controller can immediately load and apply these new compensation parameters to perform motion compensation for the motion table. Once the motion table controller has applied the new compensation parameters, it can immediately start the next round of scanning measurement. Multiple rounds of scanning and compensation are iteratively executed until the motion table residual calculated based on the compensation parameters tends to stabilize. The finally determined compensation parameters are then compiled into the first compensation table. After completing each round of scanning, it is necessary not only to calculate the motion table residual after applying the current compensation parameters but also to generate the compensation parameters for that round. The stability of the motion table residual can be determined by judging that it is less than a preset threshold. The specific preset threshold depends on the actual situation. The required positioning accuracy of the motion table can be flexibly set. The round corresponding to the motion table residual that is less than the preset threshold is regarded as the last round. The compensation parameters generated in the last round of iteration that can stabilize the residual and the compensation parameters generated in all previous rounds are organized to obtain the first compensation table. For example, for the same second feature point, if the motion table residual of the third round is 0.01 which is less than the preset threshold, then the compensation parameter for the location of the second feature point is calculated as 0.07 (i.e., 0.01+0.03+0.04) by combining the motion table residuals of the third round and the second round (0.03) and the motion table residual of the first round (0.04). The compensation parameters for the locations of other second feature points are calculated in the same way, and the first compensation table can be obtained in this way. In this way, the calibration mechanism of "multi-round scanning - dynamic feedback - iterative convergence" provides a high-precision benchmark model for subsequent error compensation. It not only eliminates accumulated deviations by clearing historical compensation parameters and uses a standard calibrated workpiece for multi-round scanning, generating compensation parameters in each round based on the deviation between the actual and theoretical positions of feature points, thus detecting systematic errors in the motion stage, but also further updates the compensation parameters by detecting the residual errors of the motion stage after error compensation. This ensures that the compensation is as accurate as possible and the residual error is as small as possible, thereby improving the positioning accuracy of the motion stage.

[0080] In the method for generating the first compensation table, the method for generating new compensation parameters in each round may include: superimposing the motion table residual measured in the current round with the compensation parameters issued in each round to obtain the true error of the motion table; and generating new compensation parameters based on the true error. Considering that the purpose of motion compensation is to offset errors and that the position deviation is obtained by subtracting the theoretical position from the actual / detected position, the compensation parameter should be a negative number of the position deviation / true error. In this way, by superimposing the residual obtained from each round of measurement with the issued compensation parameters, the accuracy bottleneck of traditional single-time error compensation is broken, and the accuracy and robustness of motion table positioning compensation are significantly improved.

[0081] In the method for generating the first compensation table, the method for measuring the motion table residual may include: after the motion table moves according to the currently issued compensation parameters, scanning the second feature point on the standard calibration workpiece again; calculating the actual position of the second feature point after remeasurement using a template matching algorithm; calculating the deviation between the actual position and the theoretical position after remeasurement, and determining this deviation as the motion table residual for the current cycle. In this way, by combining the template matching algorithm with the depth of feature point measurement, a high-precision measurement method of "image recognition - pixel-level positioning - deviation calculation" is constructed, which can significantly improve the positioning accuracy of feature points and ensure the accuracy of residual calculation.

[0082] Specifically, in the first round, the terminal device controls the motion table to move the standard calibration workpiece and controls the image acquisition device to capture an image of the workpiece. The terminal device can then calculate the actual position of the second feature points based on the second feature points in the workpiece image and a template matching algorithm. Furthermore, the terminal device can determine the motion table error for the first round based on the deviation between the actual position and the predetermined theoretical position of the second feature points. This motion table error can include the positioning error corresponding to the position of each second feature point, i.e., each first position. For example, in the first round, the motion table is determined to be in... Figure 4 The positioning error of the first position (75, 300) is (-1.6, -1.6) (represented only by 1.6 in the figure). This means that the actual position of the motion stage is (75-1.6, 300-1.6). If the actual position of the motion stage is to reach (75, 300), the motion stage needs to move an additional 1.6 in both the x-axis and y-axis directions. Based on this positioning error, the first displacement compensation amount (1.6, 1.6) corresponding to the first position (75, 300) in the first round can be generated. (1.6, 1.6) represents the additional displacement adjustment required in the x-axis and y-axis directions when the terminal device controls the motion stage to move to the first position (75, 300). The positioning errors and first displacement compensation amounts of the other first positions are similar to those of the first position (75, 300). For simplicity, only the first position (75, 300) is used to illustrate the scanning and compensation in multiple rounds. The compensation parameters for the first round can be obtained through the scanning measurement in the first round. The compensation parameters for the first round may include the first displacement compensation amount corresponding to each first position.

[0083] In the second round, the terminal device sends the compensation parameters from the first round to the motion table. After the motion table moves according to the currently sent compensation parameters, it scans the second feature point on the standard calibration workpiece again and calculates the actual position of the second feature point through a template matching algorithm. Then, the terminal device determines the motion table residual for the second round based on the deviation between the actual position of the second feature point and the predetermined theoretical position. This motion table residual may include the residual error corresponding to each first position. For example... Figure 5 As shown, in the second round, the residual error of the motion table at the first position (75, 300) is determined to be -0.1. This indicates that the actual position of the motion table is (75-0.1, 300-0.1). To achieve the actual position of the motion table at (75, 300), the motion table needs to be controlled to move 0.1 less in both the x-axis and y-axis directions. Based on this residual error, the first displacement compensation amount (-0.1, -0.1) corresponding to the first position (75, 300) in the second round can be generated (represented only by -0.1 in the figure). (-0.1, -0.1) represents the additional displacement adjustment required in the x-axis and y-axis directions when the terminal device controls the motion table to move to the first position (75, 300). The terminal device can superimpose the motion table residual measured in the second round with the compensation parameters of the first round that have already been issued to obtain the compensation parameters for the second round. For the first position (75, 300), the compensation parameters of the first round (1.6, 1.6) and the compensation parameters of the second round (-0.1, -0.1) are added along the corresponding axes (i.e., 1.6 - 0.1 is performed on both the x-axis and y-axis) to obtain the first compensation displacement (1.5, 1.5) corresponding to the first position (75, 300) in the second round. This compensation amount can be simplified to... Figure 6 The new compensation parameter 1.5 corresponds to the first position (75,300).

[0084] The calculation of compensation parameters for the third, fourth, ... Nth rounds is similar to that for the second round, and will not be repeated here. In this example, the eighth round is considered the last round when the motion table residual is determined to be less than the preset threshold. The compensation parameters generated in the eighth round to stabilize the residual are then superimposed with the compensation parameters generated in the previous seven rounds to obtain the first compensation table. The superposition process is similar to the superposition process of the compensation parameters from the first and second rounds, and will not be repeated here for the sake of simplicity.

[0085] The following example illustrates the process of calculating the actual position of the second feature point using a template matching algorithm. First, a template image is acquired to construct a high-precision matching benchmark. Specifically, the terminal device controls an image acquisition device to capture an image containing only the second feature point (e.g., a cross mark) of the standard calibration workpiece. The terminal device then binarizes the captured image to separate the target region (cross mark) from the background, extracting its minimum bounding rectangle as the template image and storing it. Next, image matching is performed based on the template image and the acquired workpiece image to quickly find the region most similar to the template image in the real-time acquired workpiece image, achieving pixel-level positioning. Specifically, the terminal device controls the motion stage and image acquisition device to work together to scan and acquire the workpiece image of the standard calibration workpiece, repeating the binarization steps in the template image acquisition, and extracting the minimum bounding rectangle of all connected regions as candidate regions. The terminal device calculates the average gray value and gray-scale ratio array for each candidate region and calculates the matching rate with the pre-stored template image. When the matching rate of a candidate region with the template image is higher than a preset threshold (e.g., the threshold is set to 95%), the candidate region is determined to be the image of the second feature point. The terminal device determines the pixel-level coordinates, i.e., the actual position, of the second feature point at the geometric center of the candidate region.

[0086] In step S102, the current residual table is determined based on the detection position and theoretical position of the first feature point on the first workpiece to be tested during the detection process.

[0087] The residual refers to the deviation between the detected position and the theoretical position, which can be calculated as Residual = Detected Position - Theoretical Position. The residual reflects the remaining operational error of the motion stage after applying the first compensation table, which may originate from placement deviations of the workpiece itself, incompleteness of the compensation table, or random errors. The current residual table is formed by collecting the residual data (detected position - theoretical position) corresponding to all first feature points. The first feature point is a point on a pattern that appears periodically on the wafer or mask, capable of image recognition and template matching. Similarly, the second feature point of the standard calibration workpiece can be a cross mark. The theoretical position of the first feature point can be designed according to actual needs. The process of obtaining the template image of the first feature point is similar to the process of obtaining the image of the second feature point of the standard calibration workpiece described above; for simplicity, it will not be elaborated here. Thus, using the first feature point located on the first workpiece to be tested for error measurement avoids the need to create a dedicated calibration workpiece for error compensation, allowing residual measurement to be completed directly on the wafer inspection process, i.e., on the corresponding semiconductor equipment production line, without switching workpieces or adjusting the inspection process, simplifying the error detection and compensation process.

[0088] The current residual table includes the second displacement compensation amount required for the motion stage to move to each second position. In fact, similar to the first compensation table, the current residual table is also a mapping table, which includes the second displacement compensation amount required for each second position the motion stage needs to move to. This compensation amount includes the compensation value in the X direction and the compensation value in the Y direction under the preset coordinate system. Specifically, the current residual table includes the amount of movement along the X-axis and the amount of movement along the Y-axis under the preset coordinate system. Each second position is the location of the graphic mark (i.e., the first feature point) of the first workpiece under test. Each second position is associated with a first feature point (such as an alignment mark, a specific circuit structure). The second positions are the points where the motion stage needs to stop and perform key feature detection, and can be distributed in the center, edge, four corners, and the entire travel range of the key area of ​​the first workpiece under test. The second positions are different from the dense calibration points (i.e., the first positions) generated when the first compensation table was generated. The sampling space where each second position is located can be called the second sampling space. The size of the second sampling space can be flexibly set according to actual needs, but the second sampling space needs to include at least the positions of all first feature points on the first workpiece under test. The coordinates of each second position in the second sampling space can also be flexibly set according to the actual situation. For example Figure 7 As shown, the second sampling space has a range of [0, 300] in both the x-axis and y-axis directions, and the sampling interval at the second position is 75. In this example, the second sampling space is the same as the first sampling space. However, in reality, the sampling ranges of the second and first sampling spaces can be completely different, and the sampling intervals at the second and first positions can also be different. This application embodiment does not limit this. To generate a denser compensation table, each second position in this application embodiment differs from each first position (see reference...). Figure 4 , Figure 5 , Figure 6 The terminal device obtains the residual error of the sampling motion table. Figure 7 The second displacement compensation values ​​for 16 second positions in the second sampling space are shown. The coordinates of these 16 second positions include (37.5, 37.5), (37.5, 112.5), (112.5, 37.5), (112.5, 262.5), (262.5, 262.5), etc. See details [link to documentation]. Figure 7 .by Figure 7Taking the second displacement compensation A2 as an example, -0.1 represents the additional displacement adjustment required in the x-axis and y-axis directions when the motion table moves to the second position (112.5, 262.5). In fact, the current residual table is similar to the first compensation table and can also be regarded as multiple coordinate-error pairs. Each coordinate represents the second position (x'', y''), and the error corresponding to the coordinate represents the second displacement compensation amount (△x2, △y2) corresponding to (x'', y''). This means that when the motion table moves to the second position, it actually needs to move x'' + △x2 in the x-axis direction and y'' + △y2 in the y-axis direction.

[0089] Step S102 may include: during the process of controlling the movement of the motion table to detect the first workpiece to be tested, when the motion table moves to a preset second position, acquiring an image of the first feature point on the first workpiece to be tested. It should be noted that the first compensation table is pre-stored in the terminal device. Subsequently, the motion table controller can receive the first compensation table from the terminal device and apply the compensation parameters therein to perform motion compensation for the motion table. Thus, during the process of the motion table moving to the preset second position, the second position is the result after applying the first compensation table. Specifically, since each second position is different from each first position, the terminal device can first determine a reference compensation amount from the first compensation table during the process of controlling the motion table to move to the second position. The reference compensation amount includes the first compensation amounts corresponding to multiple first positions adjacent to the second position. For example, if the terminal device controls the motion table to move to the second position (37.5, 262.5), then based on the second position (37.5, 262.5), it determines the four adjacent first positions, namely (0, 225), (0, 300), (75, 225), and (75, 300), and uses the first compensation amount corresponding to these four positions as the reference compensation amount. See [link to relevant documentation]. Figure 8 The compensation parameters for the second position (37.5, 262.5) are estimated based on the reference compensation amount. For example, the compensation parameters are (1.5, 1.7). This means that during the process of controlling the motion stage to move to the second position, the terminal device needs to control the motion stage to move an additional 1.5 on the x-axis and an additional 1.7 on the y-axis. The methods for estimating the compensation parameters for the second position based on the reference compensation amount include, but are not limited to, weighted calculation and bilinear interpolation. The embodiments in this application are not limited to these methods. After compensating the motion stage using the compensation parameters for the second position estimated based on the reference compensation amount, steps such as obtaining the image of the first feature point are then performed. In this way, using the pre-determined first compensation table to perform positioning compensation for the motion stage helps to obtain a more accurate motion stage residual.

[0090] After acquiring the image of the first feature point on the first workpiece to be tested, the detection position of the first feature point can be determined by image recognition based on the image and a pre-stored template image. Specifically, a template matching algorithm can be used to perform sliding matching of the pre-stored template image of the first feature point on the acquired image of the first feature point, extracting multiple candidate regions from the acquired image of the first feature point. By calculating the similarity between the template image and each candidate region, the center position of the candidate region with the highest similarity is determined as the actual / detection position of the first feature point. The positional deviation between the detection position and the corresponding theoretical position is calculated. Image processing and deviation calculation can be performed during the motion between the two feature points without occupying additional motion time, thereby minimizing the impact on detection efficiency. Based on the positional deviation corresponding to each second position... This forms the current residual table, which may include the compensation parameters for the second position corresponding to each first feature point. For each first feature point, the corresponding deviation can be calculated by the deviation ΔX in the X direction = actual X coordinate - theoretical X coordinate, and the deviation ΔY in the Y direction = actual Y coordinate - theoretical Y coordinate. For example, if the actual position of a first feature point is (73.4, 298.4) and the theoretical position is (75, 300), then the corresponding deviation can be calculated as (-1.6, -1.6). Considering that the purpose of motion compensation is to offset the error and the position deviation is obtained by subtracting the theoretical position from the actual / detected position, the compensation parameter should be the negative of the position deviation / true error. In this example, the deviation is (-1.6, -1.6), and the corresponding compensation parameter is (1.6, 1.6). In this way, by triggering residual measurement in real time during the first workpiece inspection process, the pain point of not considering residual error in the traditional solution is solved. The high-precision positioning method based on image recognition can ensure the accuracy of residual quantification. This error measurement method of "real-time image recognition - feature point positioning - deviation quantification" not only realizes the real-time capture of residual error, but also ensures the measurement accuracy of the compensation basis, providing high-quality data input for the subsequent iterative optimization of the second compensation table.

[0091] In determining the current residual table, the process of determining the detection location of the first feature point based on the image and a pre-stored template image through image recognition includes: using a template matching algorithm to perform sliding matching of the pre-stored template image in the acquired image; calculating the similarity between the template image and each candidate region in the acquired image; and determining the location of the candidate region with the highest similarity as the detection location of the first feature point. In this way, the template matching algorithm achieves precise localization of the first feature point detection location, combining the global search capability of sliding matching with the local discrimination capability of similarity quantification to form a two-layer recognition mechanism of "coarse localization-fine screening," providing reliable feature point location data for residual calculation in semiconductor testing.

[0092] When the terminal device compensates the motion table based on the first compensation table to control the motion table to move to the second position, it acquires a workpiece image of the first feature point on the first workpiece to be tested. Using a template matching algorithm, the pre-stored template image of the first feature point is slidably matched in the acquired workpiece image. Specifically, refer to the process described above of calculating the actual position of the second feature point using the template matching algorithm. Multiple candidate regions are extracted from the workpiece image. By calculating the similarity between the template image and each candidate region, the center position of the candidate region with the highest similarity is determined as the actual / detection position of the first feature point. Then, the positional deviation between the actual position of the first feature point and the theoretical position corresponding to the first feature point is calculated, thereby forming the current residual table based on the positional deviation corresponding to each second position. For example, if the calculated result of subtracting the corresponding coordinate of the theoretical position from the actual position's coordinates in the x-axis and y-axis is -0.1, then the second displacement compensation amount for the corresponding second position can be determined as (0.1, 0.1). The second displacement compensation amounts for the other second positions are similarly calculated and will not be elaborated further.

[0093] In step S103, a second compensation table is determined based on the first compensation table and the current residual table.

[0094] A denser second compensation table is determined by using the first displacement compensation amount corresponding to each first position and the second displacement compensation amount corresponding to each second position. The process of generating the second compensation table by associating the first compensation table with the current residual table can be as follows: first, a target position set is determined; then, the first set of target compensation values ​​from the first compensation table and the second set of target compensation values ​​from the current residual table are obtained from the target position set; finally, the second compensation table is generated by data fusion based on the first and second set of target compensation values. The specific process is described later. The second compensation table is used as the first compensation table for detecting the second workpiece under test. After completing the detection of the first workpiece under test, the terminal device can store the second compensation table and use it as the first compensation table (i.e., the initial compensation table) when detecting the second workpiece under test, thereby realizing the transfer and optimization of compensation. The second workpiece under test can be the first workpiece under test or a different workpiece under test. The second compensation table includes the third displacement compensation amount required to adjust the motion table when moving to each third position. It is understandable that, within the same sampling space, the position density of the third position is greater than that of the first position, the position density of the third position is greater than that of the second position, and the position density of the third position is greater than or equal to that of the first and second positions. The same sampling space refers to, for example, a sampling space B with a range of [0, 300] in both the x-axis and y-axis directions. The sampling interval for the third position is 5, the sampling interval for the first position is 10, and the sampling interval for the second position in the current residual table is 15. The third position is determined based on the first and second positions. For example... Figure 9The second compensation table shown includes third displacement compensation amounts for 81 third positions, compared to Figure 4 The first compensation table shown can be seen Figure 9 The second compensation table shown is denser, and the accuracy of the compensation amounts at each third position is also improved. The interpretation of the third displacement compensation amount is the same as that of the first and second displacement compensation amounts, and will not be repeated here for the sake of brevity.

[0095] Step S103 may include: determining a target location set; specifically, first determining the spatial range and resolution of the target location set, then generating a regular grid point set to determine a target location set, wherein the location density of the target location set is greater than or equal to the location density of the first location and the second location; the target location set may include all first locations, all second locations, and other locations for which compensation amounts have not been determined; obtaining the first set of target compensation values ​​of the first compensation table on the target location set; for example, using an interpolation algorithm, calculating the first set of target compensation values ​​for each third location in the target location set based on the first location and its corresponding first displacement compensation amount, such as... Figure 10 As shown, after interpolating the first compensation table, a first set of target compensation values ​​can be obtained. The interpolation process can be understood as follows: if the compensation value for position A is needed, the compensation values ​​of multiple positions surrounding position A can be obtained, and the compensation value for position A can be estimated based on these compensation values. The first set of target compensation values ​​reflects the amount of systematic error compensation. Furthermore, a second set of target compensation values ​​is obtained from the current residual table on the target position set. For example, an interpolation algorithm can be used to calculate the second set of target compensation values ​​for each target position in the target position set based on the second position and its corresponding second displacement compensation amount. Figure 11 As shown, after interpolating the current residual table, the first set of target compensation values ​​can be obtained. Interpolation can be understood as obtaining the compensation values ​​of multiple locations surrounding location A and estimating the compensation value of location A based on these values. The second set of target compensation values ​​reflects the dynamic error correction amount. Based on the first and second sets of target compensation values, a third displacement compensation amount is generated on the target location set through data fusion. Data fusion can be performed using a direct superposition method, such as... Figure 12As shown, the compensation amount 1.2 corresponding to position (0,300) in the first set of target compensation values ​​is added to the compensation amount 0.2 corresponding to position (0,300) in the second set of target compensation values ​​to obtain the third displacement compensation amount 1.4 corresponding to (0,300). The other positions are calculated similarly to (0,300), thus obtaining the third displacement compensation amount on the target position set, i.e., the second compensation table. In this way, by constructing a target position set with a higher position density than the first and second positions, the spatial resolution of the compensation table can be improved, and the compensation accuracy for error-sensitive positions such as workpiece edges and feature-dense areas can be significantly improved. At the same time, by fusing the first compensation table reflecting the systematic error of the semiconductor testing equipment and the current residual table reflecting the dynamic residual of the semiconductor testing equipment through a multi-source data fusion algorithm, the second compensation table is obtained. This method has a closed-loop capability of "detection-feedback-evolution", which changes the industry practice of semiconductor testing equipment relying on periodic shutdown calibration.

[0096] In determining the second compensation table, the aforementioned determination of a target location set may include: calculating the greatest common divisor (GCD) of the sampling intervals of the first and second locations. For example, the sampling interval of the first location can be determined based on the distribution interval of the second feature points on the standard calibration workpiece. If the distribution interval of the feature points on the standard calibration workpiece is 5, then the distribution interval of the feature points on the standard calibration workpiece can be used as the sampling interval of the first location, i.e., the sampling interval of the first location is also 5. Similarly, the sampling interval of the second location can be determined based on the distribution interval of the first feature points on the first workpiece to be tested. Based on the GCD, a target location set with a denser sampling interval is generated, where the GCD is a number that is divisible by both the sampling interval of the first and second locations. To ensure that the final mesh is sufficiently dense, the GCD can be divided by an integer to further increase the density of the target location set, but it should be noted that the new mesh nodes may not completely overlap with some of the original points. Specifically, the process of generating a target location set with a denser sampling interval based on the GCD may include the following three steps. The first step is to determine the grid coverage area by obtaining the minimum and maximum values ​​of the first and second position sets in the X and Y directions, respectively, and using these values ​​to define a rectangular area as the coverage area of ​​the target grid. The second step is to generate a regular grid matrix. In the X direction, starting from Xmin, incrementing by the common divisor of the X-direction until Xmax, a series of X coordinates are generated. In the Y direction, starting from Ymin, incrementing by the common divisor of the Y-direction until Ymax, a series of Y coordinates are generated. All (X,Y) coordinate pairs are generated. The third step is to output the target position set. The set consisting of all the generated (X,Y) coordinate pairs is the target position set. Its position density can be greater than or equal to the density of the original two sets, where the original two sets refer to the first position set consisting of all first positions and the second position set consisting of all second positions. For example, if the sampling interval of the first position includes a sampling interval ΔX1=10mm in the X direction and a sampling interval ΔY1=10mm in the Y direction, and the sampling interval of the second position includes a sampling interval ΔX2=15mm in the X direction and a sampling interval ΔY2=6mm in the Y direction, then the greatest common divisor of the sampling interval of the first position and the sampling interval of the second position in the X direction can be calculated to be 5mm, and the greatest common divisor of the sampling interval of the first position and the sampling interval of the second position in the Y direction is 2mm. The sampling interval / grid spacing of the target position set generated accordingly includes a sampling interval of 5mm in the X direction and a sampling interval of 2mm in the Y direction. It can be seen that the nodes of the grid simultaneously cover all X points with intervals of 10mm and 15mm and all Y points with intervals of 10mm and 6mm.In this way, by determining the target position set whose position density is greater than or equal to that of the first and second positions, the third displacement compensation amount generated on the target position set can solve the problem that traditional fixed-interval sampling is prone to missing key errors due to sparse sampling points. Furthermore, the generated second compensation table can retain the systematic error compensation amount of the first compensation table and also cover the dynamic error correction amount of the current residual table, avoiding the loss of compensation information and improving the compensation accuracy.

[0097] Sometimes the sampling intervals at the first and second positions may not have a common divisor. In such cases, the target position set can be directly taken as the set with the smaller sampling interval between the two compensation tables (i.e., the first compensation table and the current residual table). Alternatively, an arbitrary sampling interval smaller than both current sampling intervals (the sampling intervals at the first and second positions) can be set to generate the target position set, such as half of the minimum sampling interval. This way, when using interpolation algorithms later, the value of any target position can be resampled from the first compensation table or the current residual table. For example, the neighboring positions of the target position in the first compensation table or the current residual table can be found, and the compensation value of the target position can be calculated based on the distance between the neighboring positions and the target position.

[0098] In determining the second compensation table, obtaining the first set of target compensation values ​​for the first compensation table on the target position set can include: using an interpolation algorithm to calculate the first set of target compensation values ​​for each position in the target position set based on the first position and its corresponding first displacement compensation amount. For example... Figure 10 As shown, if the compensation value for position (37.5, 262.5) is needed, several surrounding positions can be determined first, such as (0, 225), (0, 300), (75, 225), and (75, 300). Then, the compensation value for position (37.5, 262.5) can be calculated based on the compensation values ​​corresponding to these four positions. The compensation value can be calculated using a weighted average. Assuming that the weights of the four positions in the example above are all 1, the compensation value for position (37.5, 262.5) can be calculated using (1.2*1 + 1.4*1 + 1.8*1 + 1.6*1) / 4. However, in reality, the specific calculation method for the compensation value depends on the interpolation algorithm used. In the process of determining the second compensation table, obtaining the second set of target compensation values ​​for the current residual table on the target position set can include: using an interpolation algorithm, calculating the second set of target compensation values ​​for each target position in the target position set based on the second position and its corresponding second displacement compensation amount. For example... Figure 11As shown, if the compensation value for position (75, 225) is needed, several surrounding positions can be determined first, such as (37.5, 225), (37.5, 262.5), (112.5, 187.5), and (112.5, 262.5). Then, the compensation value for position (37.5, 262.5) can be calculated based on the compensation values ​​corresponding to these four positions. Taking the weighted average as an example, assuming the weights of the four positions in the above example are all 0.5, the compensation value for position (37.5, 262.5) can be calculated using (1.2*0.5 + 1.4*0.5 + 1.8*0.5 + 1.6*0.5) / 4. In this way, by interpolating the first compensation table and the current residual table, mathematical modeling can be used to fill the error gaps between discrete sampling points, which helps improve the error compensation accuracy of the semiconductor testing equipment's motion stage.

[0099] Specifically, since the first sampling space and sampling interval corresponding to the first position may differ from the second sampling space and sampling interval corresponding to the second position, in order to achieve data fusion of the first displacement compensation amount and the second displacement compensation amount corresponding to the same position, this embodiment first calculates the greatest common divisor of the sampling interval of the first position and the sampling interval of the second position. For example Figure 13 The sampling interval of the first position in the first compensation table shown is 10, and the sampling interval of the second position in the current residual table is 15. Therefore, the greatest common divisor of 10 and 15 is 5. Thus, a target sampling space with a sampling interval of 5 can be formed. Each third position in the target sampling space constitutes the target position set, including... Figure 10 The values ​​(0,0), (0,5), (0,30), and (30,0) are used. The size of the target sampling space can encompass both the first and second sampling spaces. Figure 10 The second compensation table only shows a portion of the target sampling space. After the terminal device determines the sampling interval of the third position in the target sampling space, it can determine the specific coordinates of each third position. Then, the first displacement compensation amount of each first position in the first compensation table and the second displacement compensation amount of each second position in the current residual table can be directly used as the third displacement compensation amount of the corresponding position in the second compensation table. See [link to details] for more information. Figure 13 This yields a second compensation table. This second compensation table can then be directly used in the subsequent testing process of the second workpiece.

[0100] In addition to the aforementioned method for determining the second compensation table, the terminal device can also, after determining the target position set, first use an interpolation algorithm to interpolate the first compensation table and the current residual table respectively, to obtain the interpolated first compensation table and the interpolated current residual table. The terminal device can use bilinear interpolation, nearest neighbor interpolation, cubic convolution interpolation, or other resampling methods to interpolate the first compensation table and the current residual table; this application does not limit this. Thus, by using resampling methods such as bilinear interpolation, nearest neighbor interpolation, and cubic convolution interpolation, discrete compensation data can be transformed into a continuous spatial model, which helps improve the error compensation accuracy and comprehensiveness of the semiconductor testing equipment's motion stage. For example... Figure 14 As shown, the second set of target compensation values ​​is calculated based on the second position and corresponding second displacement compensation amount in the current residual table. The second set of target compensation values ​​includes the second target compensation value for each third position in the target position set. For example, the second target compensation value corresponding to the third position (5,5) is 0.11. The process of determining the first set of target compensation values ​​is similar to that of determining the second set of target compensation values, and will not be repeated here. Through interpolation, two error compensation tables with the same sampling range and the same sampling interval can be obtained: the interpolated first compensation table and the interpolated current residual table. The terminal device can use a direct superposition data fusion method to superimpose these two error compensation tables to obtain the second compensation table. For details, please refer to [link to relevant documentation]. Figure 12 Besides direct data fusion, terminal devices can also use the Kalman filter algorithm for data fusion. In this way, using the Kalman filter algorithm, which separates error and noise through mathematical modeling, during the data fusion process results in more realistic and accurate new compensation values, eliminating the influence of single abnormal fluctuations. This helps achieve high-precision data fusion and is suitable for semiconductor testing scenarios with high precision requirements. In fact, other data fusion algorithms can be selected based on the actual situation, and this application does not limit this choice.

[0101] After generating the second compensation table, the terminal device can use the second compensation table as the first compensation table when testing the second workpiece. That is, during the process of controlling the movement of the motion table to test the second workpiece, the displacement of the motion table to each third position is adjusted based on the second compensation table.

[0102] After the terminal device detects the second workpiece to be tested, the method may further include: updating the current residual table based on the detection of the second workpiece to be tested, that is, updating the current residual table based on the detection / actual position and theoretical position of the second feature point on the second workpiece to be tested during the detection process. This update process is similar to the process described above of determining the current residual table based on the detection position and theoretical position of the first feature point on the first workpiece to be tested during the detection process. For details, please refer to the relevant content of step S102 above. For the sake of brevity, it will not be repeated here. Based on the second compensation table and the updated current residual table, a third compensation table for detecting the third workpiece to be tested is determined. The third workpiece to be tested may be a workpiece to be tested that is different from the second workpiece to be tested. The process of determining the third compensation table is similar to the process of determining the second compensation table. For the sake of brevity, please refer to the relevant content of step S103 above. For the sake of brevity, it will not be repeated here. This process is repeated in different workpieces to be tested to adaptively and iteratively update the error compensation table. In this way, by measuring residual error while performing defect detection, the error of the motion table during actual operation can be obtained, so as to correct the error difference between actual operation and calibration, achieve long-term error tracking and maintain long-term detection accuracy, and perform adaptive iterative updates based on the compensation results of different workpieces to be tested, so as to obtain a more dense and comprehensive error compensation table and improve the adaptability of complex workpiece detection.

[0103] This application embodiment also provides an error compensation device for a motion table, the motion table being used to carry a first workpiece to be tested and a second workpiece to be tested. The device includes: a motion adjustment module, used to adjust the displacement of the motion table to each first position based on a first compensation table during the process of controlling the motion table to move to detect the first workpiece to be tested, the first compensation table including a first displacement compensation amount required for the motion table to move to each first position; a residual determination module, used to determine a current residual table based on the detection position and theoretical position of a first feature point on the first workpiece to be tested during the detection process, the current residual table including a second displacement compensation amount required for the motion table to move to each second position; and a compensation determination module, used to determine a second compensation table based on the first compensation table and the current residual table, the second compensation table including a third displacement compensation amount required for the motion table to move to each third position, the second compensation table being used as a first compensation table for detecting the second workpiece to be tested, the third position being determined based on the first position and the second position.

[0104] In one possible implementation, the device includes a first compensation table generation module, configured to: clear the historical compensation parameters of the motion stage controller; control the motion stage to move to perform multiple rounds of scanning measurements on a standard calibration workpiece mounted thereon; in each round, determine the motion stage error based on the deviation between the actual and theoretical positions of the second feature points obtained by scanning; generate compensation parameters for that round based on the motion stage error and send them to the motion stage controller; iteratively execute multiple rounds of scanning and compensation until the motion stage residual calculated based on the compensation parameters tends to stabilize, and organize the finally determined compensation parameters into the first compensation table.

[0105] In one possible implementation, the device includes a compensation parameter generation module, configured to: superimpose the motion table residual measured in the current round with the currently issued compensation parameters; process the superimposed data to estimate the true error of the motion table; and generate new compensation parameters based on the estimated true error.

[0106] In one possible implementation, the device includes a motion table residual measurement module, configured to: scan the second feature point on the standard calibration workpiece again after the motion table moves according to the currently issued compensation parameters; calculate the actual position of the second feature point after remeasurement using a template matching algorithm; calculate the deviation between the actual position and the theoretical position after remeasurement, and determine the deviation as the motion table residual for the current cycle.

[0107] In one possible implementation, the residual determination module includes: an image acquisition module, configured to acquire an image of a first feature point on the first workpiece under test when the motion table moves to a preset second position during the process of controlling the motion table to move and detect the first workpiece under test; an image recognition module, configured to determine the detection position of the first feature point by image recognition based on the image and a pre-stored template image; and calculate the positional deviation between the detection position and the corresponding theoretical position; and a residual formation module, configured to form the current residual table based on the positional deviation corresponding to each second position.

[0108] In one possible implementation, the image recognition module includes: a sliding matching module, used to perform sliding matching of the pre-stored template image in the acquired image using a template matching algorithm; a similarity calculation module, used to calculate the similarity between the template image and each candidate region in the acquired image; and a detection module, used to determine the position of the candidate region with the highest similarity as the detection position of the first feature point.

[0109] In one possible implementation, the compensation determination module includes: a set determination module, configured to determine a target location set, wherein the location density of the target location set is greater than or equal to the location densities of the first location and the second location; a compensation value determination module, configured to obtain a first set of target compensation values ​​of the first compensation table on the target location set, and to obtain a second set of target compensation values ​​of the current residual table on the target location set; and a generation module, configured to generate a third displacement compensation amount of the second compensation table on the target location set through data fusion based on the first set of target compensation values ​​and the second set of target compensation values.

[0110] In one possible implementation, the set determination module includes a first submodule for: calculating the greatest common divisor of the sampling interval of the first position and the sampling interval of the second position; and generating a set of the target positions with a denser sampling interval based on the greatest common divisor.

[0111] In one possible implementation, the compensation value determination module includes a first interpolation module, configured to: use an interpolation algorithm to calculate a first set of target compensation values ​​for each position in the target position set based on the first position and its corresponding first displacement compensation amount; the compensation value determination module further includes a second interpolation module, configured to: use the interpolation algorithm to calculate a second set of target compensation values ​​for each target position in the target position set based on the second position and its corresponding second displacement compensation amount.

[0112] In one possible implementation, the interpolation algorithm is any one of bilinear interpolation, nearest neighbor interpolation, or cubic convolution interpolation.

[0113] In one possible implementation, the data fusion uses a Kalman filter algorithm, or the data fusion method is direct superposition.

[0114] In one possible implementation, after inspecting the second workpiece to be tested, the apparatus further includes an update module for: updating the current residual table based on the inspection of the second workpiece to be tested; determining a third compensation table for inspecting the third workpiece to be tested based on the second compensation table and the updated current residual table; and repeating this process in different workpieces to be tested to adaptively iteratively update the error compensation table.

[0115] In one possible implementation, the first feature point is a pattern that appears periodically on a wafer or mask and is capable of image recognition and template matching.

[0116] In some embodiments, the functions or modules of the apparatus provided in this application can be used to perform the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0117] This application also provides an error compensation device, including a memory, a plurality of processors, and a computer program stored in the memory, wherein one of the plurality of processors executes the computer program to implement the steps of the above method.

[0118] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0119] Computer-readable storage media can be tangible devices capable of holding and storing programs / instructions used by instruction execution devices. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0120] The computer program (or computer-readable program instructions) described herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage medium in the respective computing / processing device.

[0121] The computer program (or computer program instructions) used to perform the operations of this application may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of this application.

[0122] Various aspects of this application are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0123] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0124] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0125] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0126] The foregoing preferred embodiments have further illustrated the objectives, technical solutions, and advantages of the present invention. It should be understood that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An error compensation method for a motion table, wherein the motion table is used to support a first workpiece to be measured and a second workpiece to be measured, characterized in that, The method includes: During the process of controlling the movement of the motion table to detect the first workpiece to be tested, the displacement of the motion table to each first position is adjusted based on the first compensation table, which includes the first displacement compensation amount required for the motion table to move to each first position. The current residual table is determined based on the detection position and theoretical position of the first feature point on the first workpiece under test during the detection process. The current residual table includes the second displacement compensation amount that needs to be adjusted when the motion table moves to each second position. A second compensation table is determined based on the first compensation table and the current residual table. The second compensation table includes the third displacement compensation amount required to adjust the motion table to each third position. The second compensation table is used as a first compensation table for detecting the second workpiece to be tested. The third position is determined based on the first position and the second position.

2. The method according to claim 1, characterized in that, The method for generating the first compensation table includes: Clear the historical compensation parameters of the motion table controller; The motion table is controlled to move so as to perform multiple rounds of scanning measurements on the standard calibration workpiece mounted on it; In each round, the motion table error for that round is determined based on the deviation between the actual and theoretical positions of the second feature point obtained by scanning. The compensation parameters for this round are generated based on the motion table error and sent to the motion table controller; The scanning and compensation are performed iteratively multiple times until the motion stage residual calculated based on the compensation parameters tends to stabilize. The finally determined compensation parameters are then organized into the first compensation table.

3. The method according to claim 2, characterized in that, Methods for generating new compensation parameters in each round include: The motion table residuals obtained from the current round of measurement are superimposed with the compensation parameters of each round that have been issued to obtain the true error of the motion table. New compensation parameters are generated based on the actual error.

4. The method according to claim 3, characterized in that, Methods for measuring motion table residuals include: After the motion table moves according to the currently issued compensation parameters, the second feature point on the standard calibration workpiece is scanned again. The actual position of the second feature point is calculated by re-measurement using a template matching algorithm; Calculate the deviation between the actual position and the theoretical position of the remeasured position, and determine the deviation as the motion table residual for the current cycle.

5. The method according to any one of claims 1 to 3, characterized in that, The current residual table is determined based on the detection position and theoretical position of the first feature point on the first workpiece under test during the detection process, including: During the process of controlling the movement of the motion table to detect the first workpiece to be tested, when the motion table moves to the preset second position, an image of the first feature point on the first workpiece to be tested is acquired; Based on the image and the pre-stored template image, the detection position of the first feature point is determined by image recognition; Calculate the positional deviation between the detected position and the corresponding theoretical position; The current residual table is formed based on the position deviation corresponding to each of the second positions.

6. The method according to claim 5, characterized in that, The step of determining the detection location of the first feature point through image recognition based on the image and the pre-stored template image includes: Using a template matching algorithm, the pre-stored template image is used for sliding matching in the acquired image; Calculate the similarity between the template image and each candidate region in the acquired image; The location of the candidate region with the highest similarity is determined as the detection location of the first feature point.

7. The method according to any one of claims 1 to 6, characterized in that, The step of determining the second compensation table based on the first compensation table and the current residual table includes: A target location set is determined, wherein the location density of the target location set is greater than or equal to the location densities of the first location and the second location; Obtain the first set of target compensation values ​​of the first compensation table on the target location set, and obtain the second set of target compensation values ​​of the current residual table on the target location set; Based on the first set of target compensation values ​​and the second set of target compensation values, the third displacement compensation amount of the second compensation table on the target position set is generated through data fusion.

8. The method according to claim 7, characterized in that, Determining a set of target locations includes: Calculate the greatest common divisor of the sampling interval at the first position and the sampling interval at the second position; Based on the greatest common divisor, a set of target locations with a denser sampling interval is generated.

9. The method according to claim 7 or 8, characterized in that, Obtaining the first set of target compensation values ​​from the first compensation table on the target location set includes: Using an interpolation algorithm, the first set of target compensation values ​​for each position in the target position set is calculated based on the first position and its corresponding first displacement compensation amount. The step of obtaining the second set of target compensation values ​​of the current residual table on the target location set includes: Using the interpolation algorithm, the second set of target compensation values ​​for each target position in the target position set is calculated based on the second position and its corresponding second displacement compensation amount.

10. The method according to claim 9, characterized in that, The interpolation algorithm is any one of bilinear interpolation, nearest neighbor interpolation, or cubic convolution interpolation.

11. The method according to any one of claims 7 to 9, characterized in that, The data fusion algorithm used is the Kalman filter algorithm, or the data fusion method used is direct superposition.

12. The method according to any one of claims 1 to 11, characterized in that, After inspecting the second workpiece to be tested, the method further includes: Update the current residual table based on the detection of the second workpiece to be tested; Based on the second compensation table and the updated current residual table, a third compensation table is determined for the detection of the third workpiece to be tested; This process is repeated on different workpieces to be tested, and the error compensation table is updated adaptively and iteratively.

13. An error compensation device for a motion table, the motion table being used to support a first workpiece to be measured and a second workpiece to be measured, characterized in that, The device includes: The motion adjustment module is used to adjust the displacement of the motion table to each first position based on a first compensation table during the process of controlling the movement of the motion table to detect the first workpiece to be tested. The first compensation table includes the first displacement compensation amount required for the motion table to move to each first position. The residual determination module is used to determine the current residual table based on the detection position and theoretical position of the first feature point on the first workpiece to be tested during the detection process. The current residual table includes the second displacement compensation amount required to adjust the motion table when it moves to each second position. The compensation determination module is used to determine a second compensation table based on the first compensation table and the current residual table. The second compensation table includes the third displacement compensation amount required for the motion table to move to each third position. The second compensation table is used as the first compensation table for detecting the second workpiece to be tested. The third position is determined based on the first position and the second position.

14. An error compensation device for a motion table, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 12.

Images