Motion platform position compensation method, apparatus, and computer-readable storage medium

Abstract

This application discloses a motion platform position compensation method, a motion platform position compensation device, and a computer-readable storage medium. The method provides a motion platform position compensation method to compensate for the measured movement position of a target object measured by a position measurement system in a given movement. The method includes: driving a motion platform to move the target object along a preset movement direction; obtaining the measured movement position of the target object in the preset movement direction as measured by the position measurement system; predicting the deviation value of the target object in the preset movement direction based on a preset difference curve; and determining the target movement position of the target object in the preset movement direction based on the deviation value and the measured movement position, thereby compensating for the measured movement position of the target object in the given movement measured by the position measurement system.

Description

Technical Field

[0001] This application relates to the field of motion platform position compensation, and more specifically, to motion platform position compensation methods, motion platform position compensation devices, and computer-readable storage media. Background Technology

[0002] Semiconductor testing is an indispensable part of the semiconductor industry. Semiconductors can be wafers awaiting testing, and semiconductor testing can include defect detection on wafers.

[0003] Specifically, a method for defect detection on a wafer can be achieved by driving a motion platform to move the wafer along a preset motion direction. The position measurement system measures the measured position of the wafer in that specific movement along the preset motion direction. A camera is then used to capture, compare, and analyze the images to determine the location and type of the defect. To accurately obtain the defect's image and position coordinates, the image must not exhibit distortion such as stretching or compression during the capture process, and the position coordinates must strictly correspond one-to-one with the actual wafer. To meet these requirements, the wafer needs to move at a fixed or stable speed so that the camera can capture images in sync with the wafer's movement speed, and subsequent stitching and MAP (bitmap) reconstruction can be performed.

[0004] However, the speed at which semiconductors (such as wafers) move depends on the speed stability of the motion platform. The motion platform is limited by factors such as guide rail stiffness and straightness, control system stability and dark noise, and measurement system accuracy. As a result, the overall speed stability it provides often has some deviations. Consequently, the measured movement position corresponding to the current movement measured by the position measurement system has a certain deviation. Therefore, there is an urgent need for a motion platform position compensation method to compensate for the measured movement position of the object under test measured by the position measurement system in the current movement. Summary of the Invention

[0005] This application provides a motion platform position compensation method, a motion platform position compensation device, and a computer-readable storage medium, which are used to provide a motion platform position compensation method to compensate the measured movement position of the object to be detected in the current movement measured by the position measurement system.

[0006] In a first aspect, embodiments of this application provide a motion platform position compensation method, including:

[0007] After the motion platform is driven to move the object to be detected along the preset motion direction, the measured movement position of the object to be detected in the current movement direction is obtained by the position measurement system.

[0008] The deviation value corresponding to the current movement of the object under test in the preset movement direction is predicted based on the preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object under test measured by the position measurement system and the ideal movement position of the object under test along the preset movement direction;

[0009] Based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, the target movement position of the object to be detected in the preset movement direction is determined. Based on the target movement position, the movement platform is controlled to move in order to perform position compensation on the measured movement position of the object to be detected in the current movement measured by the position measurement system.

[0010] Optionally, the motion platform is equipped with a calibration system; the preset motion direction is the X-axis direction of the motion platform;

[0011] Before predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the method further includes:

[0012] Determine the target length;

[0013] By driving the motion platform to move the object to be detected sequentially along the X-axis by a target length, the difference between the first and second moving positions corresponding to each movement is obtained; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the X-axis direction measured by the position measurement system; and the second moving position corresponding to each movement is the second moving position of the object to be detected in the X-axis direction measured by the calibration system.

[0014] The preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm.

[0015] Optionally, the object to be tested on the motion platform is equipped with a calibration system; the preset motion direction is the Y-axis direction of the motion platform;

[0016] Before predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the method further includes:

[0017] Determine the target length;

[0018] By driving the motion platform to move the object to be detected sequentially along the Y-axis by a target length, the difference between the first and second moving positions corresponding to each movement is obtained; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the Y-axis direction measured by the position measurement system; and the second moving position corresponding to each movement is the second moving position of the object to be detected in the Y-axis direction measured by the calibration system.

[0019] The preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm.

[0020] Optionally, after obtaining the difference between the first and second moving positions corresponding to each movement by driving the motion platform to move the object to be detected sequentially along the Y-axis direction by the target length, the method further includes:

[0021] If the difference between the first and second moving positions corresponding to the Pth move exceeds a preset threshold range, the difference is discarded, and the average of the difference p1 between the first and second moving positions corresponding to the P-1th move and the difference p3 between the first and second moving positions corresponding to the P+1th move is taken as the difference p2 between the first and second moving positions corresponding to the Pth move, where P is an integer and P≥2;

[0022] The step of fitting the preset difference curve based on the difference corresponding to each movement using an interpolation algorithm includes:

[0023] The preset difference curve is obtained by fitting the difference corresponding to each movement after the elimination process using an interpolation algorithm.

[0024] Optionally, a camera is mounted on the motion platform along the Z-axis; the object to be detected is a wafer, which includes N*M chips, where N≥2 and M≥2.

[0025] After the motion platform is driven to move the object to be detected along a preset motion direction, the method further includes:

[0026] If a preset trigger condition is met, the camera is triggered to take a picture according to a preset field of view, thereby obtaining the image corresponding to the current movement; wherein, the preset field of view is a parameter pre-configured by the camera; the image capture is performed using at least one chip;

[0027] After determining the target movement position of the object to be detected in the preset movement direction based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, the method further includes:

[0028] The restored bitmap of the object to be detected is obtained based on the image and the target movement position corresponding to the current movement.

[0029] Optionally, obtaining the reconstructed bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement includes:

[0030] Determine the first coordinate system of the motion platform and the second coordinate system of the bitmap display plane;

[0031] Determine the mapping relationship between the first coordinate system and the second coordinate system;

[0032] Based on the mapping relationship, the target movement position is converted into the restored movement position;

[0033] The image is presented at the restored movement position on the bitmap presentation plane to obtain a restored bitmap of the object to be detected.

[0034] Optionally, after obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement, the method further includes:

[0035] Defect detection is performed on the restored bitmap based on a preset standard image to obtain the detection result; or

[0036] The restored bitmap is subjected to defect detection based on a defect detection algorithm to obtain the detection results.

[0037] Secondly, embodiments of this application provide a motion platform position compensation device, comprising:

[0038] The obtaining unit is used to obtain the measured movement position of the object to be detected in the preset movement direction by driving the motion platform to move along the preset movement direction.

[0039] The prediction unit is used to predict the deviation value corresponding to the current movement of the object to be detected in the preset movement direction based on a preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset movement direction.

[0040] The position compensation unit is used to determine the target movement position of the object to be detected in the preset movement direction based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, and to control the movement of the motion platform based on the target movement position to perform position compensation on the measured movement position of the object to be detected measured by the position measurement system in the current movement.

[0041] Thirdly, embodiments of this application provide a motion platform position compensation device, comprising:

[0042] Central processing unit, memory, input / output interfaces, wired or wireless network interfaces, and power supply;

[0043] The memory is either a short-term storage memory or a persistent storage memory;

[0044] The central processing unit is configured to communicate with the memory and execute instructions in the memory to perform the aforementioned motion platform position compensation method.

[0045] Fourthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the aforementioned motion platform position compensation method.

[0046] Fifthly, embodiments of this application provide a computer program product containing instructions that, when run on a computer, cause the computer to execute the aforementioned motion platform position compensation method.

[0047] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: by driving the motion platform to move the object to be detected along a preset motion direction, the measured movement position of the object to be detected in the current movement direction measured by the position measurement system is obtained. Based on the preset difference curve, the deviation value corresponding to the current movement of the object to be detected in the preset motion direction is predicted. The preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction. Based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, the target movement position corresponding to the current movement of the object to be detected in the preset motion direction is determined. Based on the target movement position, the motion platform is controlled to move, so as to perform position compensation on the measured movement position of the object to be detected measured by the position measurement system in the current movement. Attached Figure Description

[0048] Figure 1 This is a schematic flowchart of a motion platform position compensation method disclosed in an embodiment of this application;

[0049] Figure 2This is a flowchart illustrating a method for determining a preset difference curve disclosed in an embodiment of this application;

[0050] Figure 3 This is a schematic diagram of a restored bitmap of an object to be detected, as disclosed in an embodiment of this application;

[0051] Figure 4 This is a schematic diagram of the structure of a motion platform position compensation device disclosed in an embodiment of this application;

[0052] Figure 5 This is a schematic diagram of another motion platform position compensation device disclosed in an embodiment of this application;

[0053] Figure 6 This is a schematic diagram of the structure of another motion platform position compensation device disclosed in the embodiments of this application. Detailed Implementation

[0054] This application provides a motion platform position compensation method, a motion platform position compensation device, and a computer-readable storage medium, which are used to provide a motion platform position compensation method to compensate the measured movement position of the object to be detected in the current movement measured by the position measurement system.

[0055] Please see Figure 1 , Figure 1 This is a flowchart illustrating a motion platform position compensation method disclosed in an embodiment of this application. The method includes:

[0056] 101. After the motion platform is driven to move the object to be detected along the preset motion direction, the measured movement position of the object to be detected in the current movement direction is obtained by the position measurement system.

[0057] In this embodiment, when performing motion platform position compensation, the measured movement position of the object to be detected can be obtained by driving the motion platform to move along a preset movement direction and then measuring the current movement position of the object to be detected in the preset movement direction as measured by the position measurement system.

[0058] 102. Based on the preset difference curve, predict the deviation value corresponding to the current movement of the object under test in the preset movement direction; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object under test measured by the position measurement system and the ideal movement position of the object under test along the preset movement direction.

[0059] After the motion platform is driven to move the object to be detected along the preset motion direction, the measured movement position of the object to be detected in the current movement direction is obtained by the position measurement system. Then, the deviation value of the object to be detected in the current movement direction can be predicted based on the preset difference curve. The preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction.

[0060] Before predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the preset difference curve can be determined by an interpolation algorithm.

[0061] Specifically, the method for determining the preset difference curve using an interpolation algorithm can be as follows: First, determine the target length. Then, drive the motion platform along the preset motion direction to move the object to be detected sequentially by the target length, and obtain the difference between the first and second moving positions corresponding to each movement. The first moving position corresponding to each movement is the first moving position of the object to be detected in the preset motion direction as measured by the position measurement system. The second moving position corresponding to each movement is the second moving position of the object to be detected in the preset motion direction as measured by the calibration system. Finally, the preset difference curve is fitted based on the difference corresponding to each movement using an interpolation algorithm. The motion platform is equipped with a calibration system, and the preset motion direction can be the pre-determined X-axis direction of the motion platform, the pre-determined Y-axis direction of the motion platform, or other pre-determined reasonable directions of the motion platform; no specific limitation is made here. Understandably, the target length can be a fixed length, meaning that the target length is moved by a fixed amount each time, and the difference between the first and second moving positions corresponding to each move is calculated. The target length can also be a variable value, for example, increasing proportionally or decreasing proportionally, meaning that the target length is in a state of flux each time. In this case, the difference between the first and second moving positions corresponding to each move is calculated.

[0062] 103. Based on the deviation value and the measured movement position of the current movement, determine the target movement position of the object to be detected in the preset movement direction. Control the movement of the motion platform based on the target movement position to compensate for the measured movement position of the object to be detected measured by the position measurement system.

[0063] After predicting the deviation value of the object to be detected in the current movement in the preset motion direction based on the preset difference curve, the target movement position of the object to be detected in the current movement in the preset motion direction can be determined based on the deviation value and the measured movement position of the current movement. Based on the target movement position, the motion platform is controlled to move, so as to perform position compensation on the measured movement position of the object to be detected in the current movement measured by the position measurement system.

[0064] In this embodiment, the motion platform can be driven to move the object to be detected along a preset motion direction to obtain the measured movement position of the object to be detected in the current movement direction as measured by the position measurement system. The deviation value of the object to be detected in the current movement direction is predicted based on the preset difference curve. The preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction. The target movement position of the object to be detected in the current movement direction is determined based on the deviation value and the measured movement position. The motion platform is controlled to move based on the target movement position to compensate for the measured movement position of the object to be detected in the current movement as measured by the position measurement system.

[0065] In the embodiments of this application, there can be various methods for motion platform position compensation, based on... Figure 1 The motion platform position compensation method shown below includes one of the methods described below.

[0066] In this embodiment, when performing motion platform position compensation, the measured movement position of the object to be detected can be obtained by driving the motion platform to move along a preset movement direction and then measuring the current movement position of the object to be detected in the preset movement direction as measured by the position measurement system.

[0067] It is understood that the object to be tested can be a semiconductor, such as a wafer. A wafer refers to a circular silicon wafer used in the semiconductor manufacturing process. The object to be tested can also be other objects that can be tested, and there are no specific limitations here. The position measurement system can be a grating ruler, which consists of a scale grating and a grating reading head. The position measurement system can also be other reasonable position measurement systems, and there are no specific limitations here.

[0068] After the motion platform is driven to move the object to be detected along the preset motion direction, the measured movement position of the object to be detected in the current movement direction is obtained by the position measurement system. Then, the deviation value of the object to be detected in the current movement direction can be predicted based on the preset difference curve. The preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction.

[0069] The preset motion direction can be the X-axis direction of the motion platform, the Y-axis direction of the motion platform, or other reasonable directions; no specific restrictions are imposed here.

[0070] If the preset motion direction is the X-axis direction of the motion platform, the preset difference curve corresponding to the X-axis direction can be pre-determined using an interpolation algorithm before predicting the deviation value corresponding to the current movement of the object under test in the preset motion direction based on the preset difference curve. Specifically, the method for determining the preset difference curve corresponding to the X-axis direction using an interpolation algorithm can be as follows: First, determine the target length. Then, by driving the motion platform along the X-axis direction, move the object under test sequentially along the target length, and obtain the difference between the first and second movement positions corresponding to each movement. Here, the first movement position corresponding to each movement is the first movement position of the object under test in the X-axis direction measured by the position measurement system, and the second movement position corresponding to each movement is the second movement position of the object under test in the X-axis direction measured by the calibration system. Finally, the preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm. The motion platform is equipped with a calibration system.

[0071] If the preset motion direction is the Y-axis of the motion platform, the preset difference curve corresponding to the Y-axis direction can be pre-determined using an interpolation algorithm before predicting the deviation value corresponding to the current movement of the object under test in the preset motion direction based on the preset difference curve. Specifically, the method for determining the preset difference curve corresponding to the Y-axis direction using an interpolation algorithm can be as follows: First, determine the target length. Then, by driving the motion platform along the Y-axis direction, move the object under test sequentially along the target length, and obtain the difference between the first and second movement positions corresponding to each movement. Here, the first movement position corresponding to each movement is the first movement position of the object under test in the Y-axis direction measured by the position measurement system, and the second movement position corresponding to each movement is the second movement position of the object under test in the Y-axis direction measured by the calibration system. Finally, the preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm. Here, the motion platform is equipped with a calibration system.

[0072] Specifically, after driving the object to be detected to move sequentially along the Y-axis by the driving motion platform, and obtaining the difference between the first and second moving positions corresponding to each move, if the difference between the first and second moving positions corresponding to the P-th move exceeds a preset threshold, the difference is discarded. The average of the difference p1 between the first and second moving positions corresponding to the P-1-th move and the difference p3 between the first and second moving positions corresponding to the P+1-th move is taken as the difference p2 between the first and second moving positions corresponding to the P-th move, where P is an integer and P≥2. Furthermore, the method for fitting the preset difference curve based on the difference corresponding to each move using an interpolation algorithm can be as follows: the preset difference curve is fitted based on the difference corresponding to each move after the discarding process using an interpolation algorithm.

[0073] It is understandable that interpolation algorithms include, but are not limited to, linear interpolation algorithms or polynomial interpolation algorithms. Using the average of the difference p1 corresponding to the (P-1)th move and the difference p3 corresponding to the (P+1)th move as the difference p2 corresponding to the Pth move can reduce the impact of the error in the difference corresponding to the Pth move on the overall result, and improve the accuracy and stability of determining the difference corresponding to each move.

[0074] It's also understandable that, besides the method described above of using the average of the differences p1 and p3 corresponding to the (P-1)th move as the difference p2 for the Pth move, another way to determine the difference p2 is to use the median of the differences for each move. Specifically, this can be achieved by sorting an unordered array and returning the data at the middle position, or by using other more efficient algorithms. Using the median of the differences for each move as p2 can reduce the impact of outliers. Alternatively, the weighted average of the differences for each move can be used as p2. Specifically, differences closer to a preset threshold can be assigned higher weights. Using the weighted average of the differences for each move as p2 can accurately reflect the overall characteristics and trends of the data.

[0075] It is worth mentioning that a preset difference curve can be fitted based on the difference (i.e., the corrected data points) corresponding to each move after the elimination process. The preset curve can be constructed through more accurate data estimation, thereby improving the accuracy of prediction. Furthermore, by using the difference (i.e., the corrected data points) corresponding to each move after the elimination process for interpolation, the actual changing trend of the difference between the move positions can be better reflected, so that a more accurate difference can be calculated between the move positions for subsequent analysis and decision-making.

[0076] It is also worth mentioning that the method of removing the difference corresponding to a certain movement that exceeds the preset threshold range, correcting the difference corresponding to that movement, and fitting a preset difference curve based on the difference after removal (corrected difference) is applicable not only to the Y-axis direction of the motion platform described above, but also to the X-axis direction of the motion platform, and other reasonable directions, which are not limited here.

[0077] For details, please refer to Figure 2 , Figure 2 This is a flowchart illustrating a method for determining a preset difference curve disclosed in an embodiment of this application. Figure 2 As can be seen, F represents the object to be tested, and G represents the calibration system. The calibration system includes, but is not limited to, interferometers and other reasonable systems used for calibration. The interferometer can be a laser interferometer, for example, a laser interferometer can be used to measure the object to be tested, and the position of the object to be tested can be determined by analyzing the changes in the interference pattern. The second movement position corresponding to each movement of the object to be tested in the preset motion direction measured by the interferometer is obtained. The deviation (error) between the actual movement position measured by the detection position measurement system and the ideal movement position of the object to be tested along the preset motion direction is used, and the positioning accuracy is compensated by an interpolation algorithm (mathematical model). The interference pattern can be a pattern of preset features or a pattern of grains (DIE).

[0078] It is worth mentioning that interpolation algorithms (mathematical models) can be used to analyze positioning compensation using a sufficiently large amount of experimental data, which improves the accuracy of determining the causes of deviations (errors) and enhances the accuracy and effectiveness of positioning compensation.

[0079] Specifically, the method for determining the preset difference curve can be as follows: First, place an interferometer G on the motion platform in advance. Then, drive the motion platform to move the target length sequentially along a preset motion direction (such as the X-axis or Y-axis of the motion platform). Read the difference between the first moving position (measured by a position measurement system, such as a grating ruler) and the second moving position (measured by a calibration system, such as the interferometer) corresponding to each movement. Record the differences at several positions along the preset motion direction (such as the X-axis or Y-axis of the motion platform). Use an interpolation algorithm to obtain a difference curve between the position measurement system and the calibration system over the entire stroke length. This difference curve can be recorded in the controller, and the deviation value at the corresponding position can be read according to the camera parameters and the interval settings required for image capture. The preset difference curve includes, but is not limited to, Formula 1:

[0080]

[0081] Where x is the first movement position (offset) of the object to be detected in the X-axis direction as measured by the position measurement system, and l i (x) Preset difference curve predicts the deviation value (offset) corresponding to the current movement of the object to be detected in the preset movement direction.

[0082] It's important to understand that a preset difference curve corresponding to a preset motion direction can be determined in advance using an interpolation algorithm. This allows for position compensation in the preset motion direction during actual detection. The preset motion direction can be a single axis (such as the X-axis or Y-axis of a motion platform). Determining the preset difference curve for a single axis improves compensation in that direction. Alternatively, the preset motion direction can be multi-axis (such as the X-axis and Y-axis of a motion platform). Determining the preset difference curves for each of the multiple axes improves compensation in their respective directions. Compared to a single axis, this increases the directional dimension of position compensation and improves its accuracy. It's also important to understand that the deviation value can be not only an offset but also a deflection angle or other reasonable deviation values; specific limitations are not specified here.

[0083] It is worth mentioning that for the method of determining the preset difference curve by interpolation algorithm using an interferometer as the calibration system, because the precision of the interferometer can reach the nanometer level, it can greatly improve the precision of the wafer movement position. Therefore, the coordinate alignment, MAP (bitmap) restoration, and defect location can be guaranteed with high precision, thereby improving the authenticity and accuracy of the captured image and the accuracy of the position coordinate restoration.

[0084] After predicting the deviation value of the object to be detected in the current movement in the preset motion direction based on the preset difference curve, the target movement position of the object to be detected in the current movement in the preset motion direction can be determined based on the deviation value and the measured movement position of the object to be detected in the current movement, so as to perform position compensation on the measured movement position of the object to be detected measured by the position measurement system.

[0085] The process involves driving a motion platform to move the object under test along a preset motion direction. If preset trigger conditions are met, a camera is triggered to take a picture according to a preset field of view. With strict coordination between the camera trigger and the wafer's movement, an image corresponding to the current movement is obtained. The preset field of view refers to parameters pre-configured for the camera. The image capture involves at least one chip. After determining the target movement position of the object under test in the preset motion direction based on the deviation value and the measured movement position corresponding to the current movement, a reconstructed bitmap of the object under test can be obtained based on the image and the target movement position. The motion platform has a camera mounted along its Z-axis, and the object under test is a wafer comprising N*M chips, where N≥2 and M≥2.

[0086] It is understandable that the preset trigger conditions can be set in advance based on camera parameters and the movement speed of the motion platform. The preset trigger conditions can be triggered by the position or by other parameters. The specifics are not limited here.

[0087] For details, please refer to Figure 3 , Figure 3 This is a schematic diagram of a restored bitmap of an object to be detected disclosed in an embodiment of this application. Figure 3 It can be seen that there are three different presentation scenarios for the restored bitmap. The restored bitmap in the first row is a presentation of three consecutive adjacent images (features or DIEs) A, B, and C arranged sequentially, and their actual positions on the object to be detected (such as a wafer) should be the non-overlapping and non-spacing arrangement shown in the first row. The restored bitmap in the second row has gaps between the three consecutive adjacent images (features or DIEs) A, B, and C, causing the captured image to miss some areas relative to the actual wafer. The restored bitmap in the third row has partial overlap of the three consecutive adjacent images (features or DIEs) A, B, and C, making it impossible to obtain an accurate image.

[0088] It's important to understand that after performing motion platform position compensation, a reconstructed bitmap of the detected object can be obtained based on the image and the target movement position corresponding to the current movement. The resulting reconstructed bitmap is close to... Figure 3 The effect shown in the first row is good, but without motion platform position compensation, because the wafer is placed on the motion platform during the image capture process and moved at a certain speed by the platform, while the camera takes pictures at fixed intervals, the instability of the motion platform's speed will cause the images from adjacent cameras to not be perfectly stitched together, often resulting in... Figure 3 The phenomena observed in the second and third rows occur when the wafer moves too fast under the influence of the motion platform. This causes gaps to appear between adjacent features, resulting in the captured image missing some areas compared to the actual wafer (e.g., ...). Figure 3 (The second line in the image); or if the wafer moves too slowly, some areas of the image will overlap, making it impossible to obtain an accurate image (e.g., the second line in the image); Figure 3 (The third line in the text), and both of the above situations are unacceptable for a precise detection system. Therefore, position compensation for the motion platform is of great significance.

[0089] It's worth noting that many factors affect the stability of wafer movement speed, such as the stability of the control system, the rigidity of the structural system, and the accuracy of the measurement system (position measurement system). These are sources of error that cannot be eliminated through optimization or improvement; they can only be obtained through an external calibration system to achieve a high-precision value. Specifically, for example, the position measurement system uses a linear encoder. The absolute position of the encoder can be directly read, processed, and fed back to the camera. The camera is triggered by pre-setting the spacing between adjacent images. However, during this process, due to factors such as the accuracy of the encoder, twisting or bending during installation, or dirt, the actual reading of the encoder may deviate from the distance the wafer has moved along the direction of motion. Please continue reading... Figure 2 ,Depend on Figure 2 It is known that wafer F should move linearly along the axis to receive the readings from the grating ruler. However, due to the aforementioned reasons, the wafer actually moves to position E-1, while the grating ruler moves to position D. This results in a difference of L between the actual movement and the feedback reading, leading to inaccuracies in the image capture position and reconstruction. Therefore, compensating for the position of the motion platform through an external calibration system is of great significance.

[0090] One method for obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement can be as follows: first, determine the first coordinate system of the motion platform and the second coordinate system of the bitmap presentation plane; then, determine the mapping relationship between the first coordinate system and the second coordinate system; next, convert the target movement position into the restored movement position based on the mapping relationship; and finally, present the image at the restored movement position on the bitmap presentation plane to obtain the restored bitmap of the object to be detected.

[0091] After obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement, defect detection can be performed on the restored bitmap. Specifically, the method for defect detection on the restored bitmap can be to perform defect detection on the restored bitmap based on a preset standard image and obtain the detection result; or to perform defect detection on the restored bitmap based on a defect detection algorithm and obtain the detection result; or other reasonable methods for defect detection on the restored bitmap can be used, which are not limited here.

[0092] It is understandable that after position compensation is performed on the measured movement position of the object to be inspected by the position measurement system, in addition to determining the position of the inspection image and restoring the MAP image, other reasonable operations can be performed to meet the needs of other wafer surface morphology inspection and position determination. Specific details are not limited here.

[0093] It is also understandable that, in addition to the method described above for determining the preset difference curve through interpolation algorithm, in addition to the method described above for obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement, and in addition to the method described above for defect detection of the restored bitmap, there can be other reasonable methods, which are not limited here.

[0094] In this embodiment, by driving a motion platform to move the object to be detected along a preset motion direction, the measured movement position of the object to be detected in the current movement direction, as measured by the position measurement system, is obtained. Based on a preset difference curve, the deviation value corresponding to the current movement of the object to be detected in the preset motion direction is predicted. The preset difference curve characterizes the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction. Based on the deviation value and the measured movement position corresponding to the current movement, the target movement position of the object to be detected in the current movement direction is determined. The motion platform is then controlled to move based on the target movement position to compensate for the measured movement position of the object to be detected measured by the position measurement system. Furthermore, by using an interpolation algorithm (mathematical model) and analyzing a sufficiently large amount of experimental data for positioning compensation, the accuracy of determining the cause of the deviation (error) is improved, thus enhancing the accuracy and effectiveness of position compensation. Next, a preset difference curve can be fitted based on the difference (i.e., the corrected data points) corresponding to each movement after the elimination process. This allows for the construction of a preset curve through more accurate data estimation, thereby improving prediction accuracy. Furthermore, interpolation using the difference (i.e., the corrected data points) corresponding to each movement after the elimination process better reflects the actual changing trend of the difference between movement positions, enabling the calculation of more accurate differences between movement positions for subsequent analysis and decision-making. Finally, the interferometer's precision reaches the nanometer level. Calibration based on the interferometer can significantly improve the accuracy of wafer movement positions, achieving real-time high-precision position compensation for the motion platform. This ensures high precision in coordinate alignment, MAP (bitmap) reconstruction, and defect location, thereby improving the realism and accuracy of captured images and the accuracy of position coordinate reconstruction.

[0095] The above describes the motion platform position compensation method in the embodiments of this application. The following describes the motion platform position compensation device in the embodiments of this application. Please refer to [link / reference]. Figure 4 One embodiment of the motion platform position compensation device in this application includes:

[0096] The obtaining unit 401 is used to obtain the measured movement position of the object to be detected in the preset movement direction by driving the motion platform to move along the preset movement direction.

[0097] The prediction unit 402 is used to predict the deviation value corresponding to the current movement of the object to be detected in the preset movement direction based on a preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset movement direction.

[0098] The position compensation unit 403 is used to determine the target movement position of the object to be detected in the preset movement direction based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, and to control the movement of the motion platform based on the target movement position to perform position compensation on the measured movement position of the object to be detected measured by the position measurement system in the current movement.

[0099] In this embodiment, the motion platform can be driven to move the object to be detected along a preset motion direction to obtain the measured movement position of the object to be detected in the current movement direction as measured by the position measurement system. The deviation value of the object to be detected in the current movement direction is predicted based on the preset difference curve. The preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset motion direction. The target movement position of the object to be detected in the current movement direction is determined based on the deviation value and the measured movement position. The motion platform is controlled to move based on the target movement position to compensate for the measured movement position of the object to be detected in the current movement as measured by the position measurement system.

[0100] The motion platform position compensation device in the embodiments of this application is described in detail below. Please refer to [link / reference]. Figure 5 Another embodiment of the motion platform position compensation device in this application includes:

[0101] The obtaining unit 501 is used to obtain the measured movement position of the object to be detected in the preset movement direction by driving the motion platform to move along the preset movement direction.

[0102] The prediction unit 502 is used to predict the deviation value corresponding to the current movement of the object to be detected in the preset movement direction based on a preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset movement direction.

[0103] The position compensation unit 503 is used to determine the target movement position of the object to be detected in the preset movement direction based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, and to control the movement of the motion platform based on the target movement position to perform position compensation on the measured movement position of the object to be detected measured by the position measurement system in the current movement.

[0104] The motion platform position compensation device also includes:

[0105] Determining unit 504 is used to determine the target length;

[0106] The obtaining unit 501 is further configured to, by driving the motion platform to move the object to be detected sequentially along the X-axis direction by a target length, obtain the difference between the first moving position and the second moving position corresponding to each movement; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the X-axis direction measured by the position measurement system; the second moving position corresponding to each movement is the second moving position of the object to be detected in the X-axis direction measured by the calibration system; the motion platform is equipped with a calibration system; the preset motion direction is the X-axis direction of the motion platform;

[0107] The fitting unit 505 is used to fit the preset difference curve based on the difference corresponding to each movement using an interpolation algorithm.

[0108] The determining unit 504 is also used to determine the target length;

[0109] The obtaining unit 501 is further configured to, by driving the motion platform to move the object to be detected sequentially along the Y-axis direction by a target length, obtain the difference between the first moving position and the second moving position corresponding to each movement; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the Y-axis direction measured by the position measurement system; the second moving position corresponding to each movement is the second moving position of the object to be detected in the Y-axis direction measured by the calibration system; the motion platform is equipped with a calibration system; the preset motion direction is the Y-axis direction of the motion platform;

[0110] The fitting unit 505 is further configured to obtain the preset difference curve by fitting the difference corresponding to each movement using an interpolation algorithm.

[0111] The motion platform position compensation device also includes:

[0112] The elimination unit 506 is used to eliminate the difference when the difference between the first moving position and the second moving position corresponding to the Pth move exceeds a preset threshold range, and to take the average of the difference p1 between the first moving position and the second moving position corresponding to the P-1th move and the difference p3 between the first moving position and the second moving position corresponding to the P+1th move as the difference p2 between the first moving position and the second moving position corresponding to the Pth move, where P is an integer and P≥2;

[0113] The fitting unit 505 is specifically used to fit the preset difference curve based on the difference corresponding to each move after the elimination process using an interpolation algorithm.

[0114] The motion platform position compensation device also includes:

[0115] Trigger unit 507 is used to trigger the camera to take pictures according to a preset field of view if a preset trigger condition is met, so as to obtain the image corresponding to the current movement; wherein, the preset field of view is a parameter pre-configured by the camera; the image is captured by at least one chip; the camera is mounted in the Z-axis direction of the motion platform; the object to be detected includes N*M chips, where N≥2 and M≥2;

[0116] The obtaining unit 501 is further configured to obtain a restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement.

[0117] The obtaining unit 501 is specifically used to determine the first coordinate system of the motion platform and the second coordinate system of the bitmap presentation plane, determine the mapping relationship between the first coordinate system and the second coordinate system, convert the target movement position into a restored movement position based on the mapping relationship, and present the image at the restored movement position on the bitmap presentation plane to obtain the restored bitmap of the object to be detected.

[0118] The motion platform position compensation device also includes:

[0119] The defect detection unit 508 is used to perform defect detection on the restored bitmap based on a preset standard image to obtain a detection result; or to perform defect detection on the restored bitmap based on a defect detection algorithm to obtain a detection result.

[0120] In this embodiment, each unit in the motion platform position compensation device performs the functions described above. Figure 1 The operation of the motion platform position compensation device in the illustrated embodiment will not be described in detail here.

[0121] Please refer to the following: Figure 6 Another embodiment of the motion platform position compensation device 600 in this application includes:

[0122] Central processing unit 601, memory 605, input / output interface 604, wired or wireless network interface 603, and power supply 602;

[0123] Memory 605 is either a short-term storage memory or a persistent storage memory;

[0124] The central processing unit 601 is configured to communicate with the memory 605 and execute instructions stored in the memory 605 to perform the aforementioned operations. Figure 1 The method in the illustrated embodiment.

[0125] This application also provides a computer-readable storage medium, which includes instructions that, when executed on a computer, cause the computer to perform the aforementioned actions. Figure 1 The method in the illustrated embodiment.

[0126] This application also provides a computer program product containing instructions, which, when run on a computer, causes the computer to perform the aforementioned... Figure 1 The method in the illustrated embodiment.

[0127] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0128] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0130] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0131] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0132] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for position compensation of a motion platform, characterized in that, include: After the motion platform is driven to move the object to be detected along the preset motion direction, the measured movement position of the object to be detected in the current movement direction is obtained by the position measurement system. The deviation value corresponding to the current movement of the object under test in the preset movement direction is predicted based on a preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object under test measured by the position measurement system and the ideal movement position of the object under test along the preset movement direction; the preset difference curve is obtained based on historical data fitting; Based on the predicted deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, the target movement position of the object to be detected in the preset movement direction is determined. Based on the target movement position, the movement platform is controlled to move in order to perform position compensation on the measured movement position of the object to be detected in the current movement measured by the position measurement system.

2. The method according to claim 1, characterized in that, The motion platform is equipped with a calibration system; the preset motion direction is the X-axis direction of the motion platform; Before predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the method further includes: Determine the target length; By driving the motion platform to move the object to be detected sequentially along the X-axis by a target length, the difference between the first and second moving positions corresponding to each movement is obtained; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the X-axis direction measured by the position measurement system; and the second moving position corresponding to each movement is the second moving position of the object to be detected in the X-axis direction measured by the calibration system. The preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm.

3. The method according to claim 1, characterized in that, The object to be tested on the motion platform is equipped with a calibration system; the preset motion direction is the Y-axis direction of the motion platform; Before predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the method further includes: Determine the target length; By driving the motion platform to move the object to be detected sequentially along the Y-axis by a target length, the difference between the first and second moving positions corresponding to each movement is obtained; wherein, the first moving position corresponding to each movement is the first moving position of the object to be detected in the Y-axis direction measured by the position measurement system; and the second moving position corresponding to each movement is the second moving position of the object to be detected in the Y-axis direction measured by the calibration system. The preset difference curve is obtained by fitting the difference corresponding to each movement using an interpolation algorithm.

4. The method according to claim 3, characterized in that, After the method involves driving the motion platform to move the object to be detected sequentially along the Y-axis by a target length, and obtaining the difference between the first and second moving positions corresponding to each movement, the method further includes: If the difference between the first and second moving positions corresponding to the Pth move exceeds a preset threshold range, the difference is discarded, and the average of the difference p1 between the first and second moving positions corresponding to the P-1th move and the difference p3 between the first and second moving positions corresponding to the P+1th move is taken as the difference p2 between the first and second moving positions corresponding to the Pth move, where P is an integer and P≥2; The step of fitting the preset difference curve based on the difference corresponding to each movement using an interpolation algorithm includes: The preset difference curve is obtained by fitting the difference corresponding to each movement after the elimination process using an interpolation algorithm.

5. The method according to claim 1, characterized in that, A camera is mounted on the motion platform along the Z-axis; the object to be detected is a wafer, which includes N*M chips, where N≥2 and M≥2. After the motion platform is driven to move the object to be detected along a preset motion direction, the method further includes: If a preset trigger condition is met, the camera is triggered to take a picture according to a preset field of view, thereby obtaining the image corresponding to the current movement; wherein, the preset field of view is a parameter pre-configured by the camera; the image capture is performed using at least one chip; After determining the target movement position of the object to be detected in the preset movement direction based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, the method further includes: The restored bitmap of the object to be detected is obtained based on the image and the target movement position corresponding to the current movement.

6. The method according to claim 5, characterized in that, The step of obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement includes: Determine the first coordinate system of the motion platform and the second coordinate system of the bitmap display plane; Determine the mapping relationship between the first coordinate system and the second coordinate system; Based on the mapping relationship, the target movement position is converted into the restored movement position; The image is presented at the restored movement position on the bitmap presentation plane to obtain a restored bitmap of the object to be detected.

7. The method according to claim 5, characterized in that, After obtaining the restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement, the method further includes: Defect detection is performed on the restored bitmap based on a preset standard image to obtain the detection result; or The restored bitmap is subjected to defect detection based on a defect detection algorithm to obtain the detection results.

8. A motion platform position compensation device, characterized in that, include: The obtaining unit is used to obtain the measured movement position of the object to be detected in the preset movement direction by driving the motion platform to move along the preset movement direction. The prediction unit is used to predict the deviation value corresponding to the current movement of the object to be detected in the preset movement direction based on a preset difference curve; wherein, the preset difference curve is used to characterize the measurement deviation between the actual movement position of the object to be detected measured by the position measurement system and the ideal movement position of the object to be detected along the preset movement direction; the preset difference curve is obtained based on historical data fitting; The position compensation unit is used to determine the target movement position of the object to be detected in the preset movement direction based on the predicted deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, and to control the movement of the motion platform based on the target movement position to perform position compensation on the measured movement position of the object to be detected in the current movement measured by the position measurement system.

9. A motion platform position compensation device, characterized in that, include: Central processing unit and memory; The memory is either a short-term storage memory or a persistent storage memory; The central processing unit is configured to communicate with the memory and execute instructions in the memory to perform the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1 to 7.

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