Motion platform position compensation method and device and computer readable storage medium

Abstract

The embodiment of the invention discloses a motion platform position compensation method, motion platform position compensation equipment and a computer readable storage medium, and is used for providing the motion platform position compensation method so as to perform position compensation on a measurement moving position, measured by a position measurement system, of current movement of a to-be-detected object. The method provided by the embodiment of the invention comprises the following steps: after driving a motion platform to drive an object to be detected to move along a preset motion direction, obtaining a measurement movement position corresponding to the current movement of the object to be detected in the preset motion direction measured by a position measurement system, predicting a deviation value corresponding to the current movement of the to-be-detected object in the preset movement direction based on a preset difference value curve, and determining a target movement position corresponding to the current movement of the to-be-detected object in the preset movement direction based on the deviation value corresponding to the current movement and the measurement movement position corresponding to the current movement, and position compensation is carried out on the measurement moving position of the current movement of the to-be-detected object measured by the position measurement system.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of motion platform position compensation, and more specifically, to a motion platform position compensation method, a motion platform position compensation device, and a computer-readable storage medium. Background Art

[0002] Semiconductor inspection is an indispensable part in the semiconductor industry. Semiconductors can be wafers waiting to be inspected, and semiconductor inspection can be defect detection on wafers, etc.

[0003] Specifically, the method for defect detection on the wafer can be to drive the motion platform to move the wafer along the preset motion direction, obtain the measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system, and determine the location and type of the defect by shooting, comparing and analyzing with the camera. If the image and position coordinates of the defect are to be accurately obtained, it is required that the image cannot be distorted such as stretching or compression during the shooting process, and the position coordinates must strictly correspond to the actual wafer one by one. To meet the above requirements, the wafer needs to move at a fixed or stable speed so that the camera can take pictures in accordance with the moving speed of the wafer, and perform subsequent stitching pictures and MAP (bitmap) restoration.

[0004] However, the speed at which a semiconductor (such as a wafer) moves depends on the speed stability of a motion platform. The motion platform is limited by the stiffness and straightness of the guide rail, the stability and dark noise of the control system, the accuracy of the measurement system, etc., and the comprehensive speed stability provided by the motion platform often has some deviations, so that the measured moving position corresponding to the current movement measured by the position measurement system has certain deviations. Therefore, a motion platform position compensation method is urgently needed to compensate for the measured moving position of the current movement of the object to be detected measured by the position measurement system. Summary of the invention

[0005] The embodiments of the present application provide 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 for the measured moving position of the object to be detected measured by a position measurement system.

[0006] In a first aspect, an embodiment of the present application provides a method for compensating a position of a motion platform, comprising:

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

[0008] Predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on a preset difference curve; wherein the preset difference curve is used to characterize the measurement deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction;

[0009] The target moving position corresponding to the current movement of the object to be detected in the preset movement direction is determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the movement of the motion platform is controlled based on the target moving position to perform position compensation for the measured moving position of the current movement of the object to be detected 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 target length;

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

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

[0015] Optionally, the object to be detected 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 target length;

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

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

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

[0021] When the difference between the first moving position and the second moving position corresponding to the P-th movement exceeds the preset threshold range, the difference is eliminated, and the average of the difference p1 between the first moving position and the second moving position corresponding to the P-1-th movement and the difference p3 between the first moving position and the second moving position corresponding to the P+1-th movement is used as the difference p2 between the first moving position and the second moving position corresponding to the P-th movement, where P is an integer and P≥2;

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

[0023] The preset difference curve is obtained by interpolation algorithm based on the difference fitting corresponding to each movement after elimination processing.

[0024] Optionally, a camera is installed in the Z-axis direction of the motion platform; the object to be detected is a wafer, and the wafer includes N*M chips, N≥2, 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 the preset trigger condition is met, the camera is triggered to take a picture according to the preset field of view to obtain an 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;

[0027] After determining the target movement position of the object to be detected corresponding to the current movement 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] A 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 a restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement includes:

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

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

[0032] Converting the target moving position into a restored moving position based on the mapping relationship;

[0033] The image is presented at the restored moved position of 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] Perform defect detection on the restored bitmap based on a preset standard image to obtain a detection result; or

[0036] Defect detection is performed on the restored bitmap based on a defect detection algorithm to obtain a detection result.

[0037] In a second aspect, an embodiment of the present application provides a motion platform position compensation device, including:

[0038] An obtaining unit, configured to obtain a measured moving position corresponding to the current movement of the object to be detected in the preset moving direction measured by the position measurement system after the moving platform drives the object to be detected to move in the preset moving direction;

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

[0040] A position compensation unit is used to determine the target movement position corresponding to the current movement 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 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.

[0041] In a third aspect, an embodiment of the present application provides a motion platform position compensation device, including:

[0042] CPU, memory, input and output interfaces, wired or wireless network interfaces, and power supply;

[0043] The memory is 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] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, which includes instructions. When the instructions are executed on a computer, the computer executes the aforementioned motion platform position compensation method.

[0046] In a fifth aspect, an embodiment of the present application provides a computer program product comprising instructions, which, when the computer program product is run on a computer, enables the computer to execute the aforementioned motion platform position compensation method.

[0047] It can be seen from the above technical scheme that the embodiments of the present application have the following advantages: after driving the motion platform to move the object to be detected along the preset motion direction, the measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system can be obtained, and the deviation value corresponding to the current movement of the object to be detected in the preset motion direction is predicted based on the preset difference curve, wherein the preset difference curve is used to characterize the measured deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction, the target moving position corresponding to the current movement of the object to be detected in the preset motion direction is determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the motion platform is controlled to move based on the target moving position to perform position compensation for the measured moving position of the object to be detected measured by the position measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A schematic flow chart of a motion platform position compensation method disclosed in an embodiment of the present application;

[0049] Figure 2A schematic diagram of a flow chart of a method for determining a preset difference curve disclosed in an embodiment of the present application;

[0050] Figure 3 A schematic diagram of a restored bitmap of an object to be detected disclosed in an embodiment of the present application;

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

[0052] Figure 5 It is a structural schematic diagram of another motion platform position compensation device disclosed in an embodiment of the present application;

[0053] Figure 6 This is a schematic structural diagram of another motion platform position compensation device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The embodiments of the present application provide 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 for the measured moving position of the object to be detected measured by a position measurement system.

[0055] See also Figure 1 , Figure 1 The following is a flow chart of a motion platform position compensation method disclosed in an embodiment of the present application, wherein the method comprises:

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

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

[0058] 102. Predicting a deviation value corresponding to the current movement of the object to be detected in a preset motion direction based on a preset difference curve; wherein the preset difference curve is used to characterize the measurement deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction.

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

[0060] Wherein, 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 through the interpolation algorithm can be, first determining the target length, and then driving the motion platform to drive the object to be detected to move the target length in sequence along the preset motion direction, and obtaining 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 corresponding to each movement of the object to be detected in the preset motion direction measured by the position measurement system; the second moving position corresponding to each movement is the second moving position corresponding to each movement of the object to be detected in the preset motion direction measured by the calibration system, and finally, through the interpolation algorithm, the preset difference curve is fitted based on the difference corresponding to each movement, wherein the motion platform is equipped with a calibration system, and the preset motion direction can be a predetermined X-axis direction of the motion platform, or a predetermined Y-axis direction of the motion platform, or other reasonable directions of the predetermined motion platform, which are not limited here. It can be understood that the target length can be a fixed length, that is, the target length is fixed each time, and the difference between the first moving position and the second moving position corresponding to each movement is calculated. The target length can also be a variable value, for example, it is increased proportionally, or it is decreased proportionally, that is, the target length of each movement is in a changing state. In this case, the difference between the first moving position and the second moving position corresponding to each movement is calculated.

[0062] 103. Determine a target moving position corresponding to the current movement of the object to be detected in a preset moving direction based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and control the movement of the motion platform based on the target moving position to perform position compensation on the measured moving position of the current movement of the object to be detected measured by the position measurement system.

[0063] After 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 target movement position corresponding to the current movement of the object to be detected in the preset motion direction can be determined based on the deviation value corresponding to the current movement and the measured movement position corresponding to the current movement, and the movement of the motion platform is controlled 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.

[0064] In an embodiment of the present application, the motion platform can be driven to move the object to be detected along a preset motion direction, and the measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system can be obtained. The deviation value corresponding to the current movement of the object to be detected in the preset motion direction is predicted based on a preset difference curve, wherein the preset difference curve is used to characterize the measured deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction. The target moving position corresponding to the current movement of the object to be detected in the preset motion direction is determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the motion platform is controlled to move based on the target moving position to perform position compensation for the measured moving position of the current movement of the object to be detected measured by the position measurement system.

[0065] In the embodiment of the present application, there are many methods for compensating the position of the motion platform. Figure 1 The motion platform position compensation method shown in the figure, one of the methods is described below.

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

[0067] It is understandable that the object to be detected can be a semiconductor, such as a wafer, etc. Wafer refers to a round silicon wafer used in the semiconductor manufacturing process. The object to be detected can also be other objects that can be detected, which are not limited 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, which are not limited here.

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

[0069] The preset motion direction may be the X-axis direction of the motion platform, the Y-axis direction of the motion platform, or other reasonable directions, which are not specifically limited here.

[0070] Wherein, 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 determined in advance by an interpolation algorithm 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. Specifically, the method for determining the preset difference curve corresponding to the X-axis direction by the interpolation algorithm can be, first determining the target length, and then driving the motion platform to drive the object to be detected to move the target length in sequence along the X-axis direction, and obtaining 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 corresponding to each movement 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 corresponding to each movement of the object to be detected in the X-axis direction measured by the calibration system, and finally, the preset difference curve is obtained by fitting based on the difference corresponding to each movement by the interpolation algorithm, wherein the motion platform is equipped with a calibration system.

[0071] Wherein, if the preset motion direction is the Y-axis direction of the motion platform, the preset difference curve corresponding to the Y-axis direction can be determined in advance by an interpolation algorithm 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. Specifically, the method for determining the preset difference curve corresponding to the Y-axis direction by the interpolation algorithm can be, first determining the target length, and then driving the motion platform to drive the object to be detected to move the target length in sequence along the Y-axis direction, and obtaining 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 corresponding to each movement 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 corresponding to each movement of the object to be detected in the Y-axis direction measured by the calibration system, and finally, the preset difference curve is obtained by fitting based on the difference corresponding to each movement by the interpolation algorithm, wherein the motion platform is equipped with a calibration system.

[0072] Among them, after driving the motion platform to move the object to be detected in sequence by the target length along the Y-axis direction, after obtaining the difference between the first moving position and the second moving position corresponding to each movement, when the difference between the first moving position and the second moving position corresponding to the P-th movement exceeds the preset threshold range, the difference can be eliminated, and the average value of the difference p1 between the first moving position and the second moving position corresponding to the P-1-th movement and the difference p3 between the first moving position and the second moving position corresponding to the P+1-th movement is used as the difference p2 between the first moving position and the second moving position corresponding to the P-th movement, wherein P is an integer, and P≥2; and wherein, the method of obtaining a preset difference curve based on the difference corresponding to each movement through an interpolation algorithm may be to obtain a preset difference curve based on the difference corresponding to each movement after the elimination process through an interpolation algorithm.

[0073] It is understandable that the interpolation algorithm includes but is not limited to a linear interpolation algorithm or a polynomial interpolation algorithm, etc. Taking the average of the difference p1 corresponding to the P-1th movement and the difference p3 corresponding to the P+1th movement as the difference p2 corresponding to the Pth movement can reduce the impact of the error of the difference corresponding to the Pth movement on the overall result and improve the accuracy and stability of the determination of the difference corresponding to each movement.

[0074] It can also be understood that, in addition to the method described above of using the average of the difference p1 corresponding to the P-1th movement and the difference p3 corresponding to the P+1th movement as the difference p2 corresponding to the Pth movement, the method of determining the difference p2 can also use the median of the difference corresponding to each movement as the difference p2. Specifically, an array of an unordered array can be sorted first, and then the data in the middle of the array can be returned. It can also be solved by other algorithms with higher processing efficiency, which are not limited here. Using the median of the difference corresponding to each movement as the difference p2 can reduce the impact of outliers. The weighted average of the difference corresponding to each movement can also be used as the difference p2. Specifically, the difference closer to the preset difference threshold can be given a higher weight, and the weighted average of the difference corresponding to each movement is used as the difference p2, which can accurately reflect the overall characteristics and trends of the data.

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

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

[0077] For details, please refer to Figure 2 , Figure 2 A schematic diagram of a flow chart of a method for determining a preset difference curve disclosed in an embodiment of the present application, comprising Figure 2 It can be seen that F is the object to be detected, G is the calibration system, and the calibration system includes but is not limited to other reasonable systems for calibration such as interferometers. The interferometer can be a laser interferometer, etc. For example, a laser interferometer can be used to measure the object to be detected, and the position of the object to be detected can be determined by analyzing the change of the interference pattern, and the second moving position corresponding to each movement of the object to be detected in the preset movement direction measured by the interferometer is obtained to detect the deviation (error) between the moving position actually measured by the position measurement system and the ideal moving position of the object to be detected along the preset movement direction, and the interpolation algorithm (mathematical model) is used to compensate for the positioning accuracy. Among them, the interference pattern can be a pattern of preset features or a pattern of grains (DIE).

[0078] It is worth mentioning that the interpolation algorithm (mathematical model) can be used to analyze the positioning compensation through a sufficiently large amount of experimental data, which improves the accuracy of determining the cause of the deviation (error) and improves the accuracy and effectiveness of the position compensation.

[0079] Specifically, the method for determining the preset difference curve may be to first place the interferometer G on the motion platform in advance, and then drive the motion platform to move the target length in sequence along the preset motion direction (such as the X-axis or Y-axis of the motion platform, etc.), and then read the difference between the first moving position (the value measured by the position measurement system such as a grating ruler) and the second moving position (the value measured by the calibration system such as an interferometer) corresponding to each movement, record the difference of several positions along the preset motion direction (such as the X-axis or Y-axis of the motion platform, etc.), and obtain a difference curve measured between the position measurement system and the calibration system within the full stroke length range through an interpolation algorithm, and this difference curve can be recorded to the controller, so that the deviation value of the corresponding position of this difference curve can be read according to the interval setting of the camera parameters and the image taking requirements. Among them, the preset difference curve includes but is not limited to Formula 1:

[0080]

[0081] Wherein, x is the first moving position (offset) corresponding to each movement of the object to be detected in the X-axis direction measured by the position measurement system, l i (x) The 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 should be understood that the preset difference curve corresponding to the preset motion direction can be determined in advance through an interpolation algorithm to perform position compensation for the preset motion direction during the actual detection process, and the preset motion direction can be a single axis (such as the X-axis or Y-axis of the motion platform, etc.), and determining the preset difference curve corresponding to the single axis can improve the compensation in the single-axis direction; the preset motion direction can also be multi-axis (such as the X-axis and Y-axis of the motion platform, etc.), and determining the preset difference curve corresponding to each of the multiple axes can improve the compensation in the corresponding directions of the multiple axes. Compared with a single axis, the directional dimension of the position compensation can be increased, and the accuracy of the position compensation can be improved. It should also be understood that in addition to the offset, the deviation value can also be a deflection angle or other reasonable deviation values, which are not limited here.

[0083] It is worth mentioning that for the method of determining the preset difference curve through the interpolation algorithm of the calibration system being an interferometer, because the accuracy of the interferometer can reach the nanometer level, the accuracy of the wafer movement position can be greatly improved, so the coordinate alignment, MAP map (bitmap) restoration, and defect position positioning 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 corresponding to the current movement of the object to be detected in the preset motion direction based on the preset difference curve, the target movement position corresponding to the current movement of the object to be detected in the preset motion direction can be determined based on the deviation value corresponding to the current movement and the measured movement position corresponding to 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] After the motion platform is driven to move the object to be detected along the preset motion direction, if the preset trigger condition is met, the camera can be triggered to take pictures according to the preset field of view, and the image corresponding to the current movement can be obtained under the condition that the triggering of the camera is strictly coordinated with the movement of the wafer; wherein the preset field of view is a parameter pre-configured by the camera; the image capture has at least one chip. After determining the target moving position corresponding to the current movement of the object to be detected in the preset motion direction based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, the restored bitmap of the object to be detected can be obtained based on the image and the target moving position corresponding to the current movement, wherein a camera is installed in the Z-axis direction of the motion platform, the object to be detected is a wafer, and the wafer includes N*M chips, N≥2, M≥2.

[0086] It is understandable that the preset trigger condition can be pre-set based on the camera parameters and the movement speed of the motion platform. The preset trigger condition can be that the position reaches the trigger condition, or it can be that other parameters reach the trigger condition, which is not specifically limited here.

[0087] For details, please refer to Figure 3 , Figure 3 A schematic diagram of a restored bitmap of an object to be detected disclosed in an embodiment of the present application, comprising Figure 3 It can be seen that there are three different presentations of restored bitmaps, among which the restored bitmap in the first row is a presentation of three consecutive adjacent images (features or DIE) A, B and C arranged in sequence, and the actual position on the object to be detected (such as a wafer) should be the arrangement without overlap and spacing as shown in the first row; the restored bitmap in the second row is that there are gaps between the three consecutive adjacent images (features or DIE) A, B and C, so that the captured picture will miss some areas relative to the real wafer; the restored bitmap in the third row is that some areas of the three consecutive adjacent images (features or DIE) A, B and C overlap, and an accurate picture cannot be obtained.

[0088] It should be understood that after the motion platform position compensation is performed, a restored bitmap of the object to be detected can be obtained based on the image and the target movement position corresponding to the current movement. The obtained restored bitmap is close to Figure 3 However, if the motion platform position compensation is not performed, the wafer is placed on the motion platform during the shooting process, and the motion platform drives it to move at a certain speed. At the same time, the camera takes pictures at fixed intervals. Due to the unstable speed of the motion platform, the pictures taken by the cameras at two adjacent positions cannot be perfectly stitched, which often results in Figure 3 The phenomenon in the second and third rows is that if the wafer moves too fast under the motion platform, gaps will appear between adjacent features, causing the captured image to miss some areas relative to the real wafer (for example, Figure 3 or the wafer moves too slowly, causing some areas of the image to overlap and making it impossible to obtain an accurate image (e.g. Figure 3 The third line in the figure), and the above two situations are not allowed to occur for the accurate detection system. Therefore, it is of great significance to compensate the position of the motion platform.

[0089] It is worth mentioning that there are many factors that affect the stability of the wafer movement speed, such as the stability of the control system, the stiffness of the structural system, and the accuracy of the measurement system (position measurement system). These are all sources of error that cannot be eliminated, so they cannot be eliminated through optimization and improvement. They can only be obtained through an external calibration system to obtain a high-precision value. Specifically, for example, the position measurement system is a grating ruler, which can directly read the absolute position of the motion system grating ruler, and feed it back to the camera after signal processing, and trigger the photo by setting the distance between two adjacent pictures in advance. However, in this process, due to the accuracy of the grating ruler, the distortion or bending and dirt of the installation, etc., the actual reading of the grating ruler and the distance the wafer moves along the direction of movement have a certain deviation. Please continue to refer to Figure 2 ,Depend on Figure 2 It can be seen that the wafer F should move along the axis in a straight line to receive the reading of the grating ruler feedback, but due to the above reasons, the actual wafer moves to the E-1 position, and the grating ruler moves to the D position, that is, there is a difference of L between the actual movement and the feedback reading, resulting in inaccurate image position and restoration. Therefore, it is of great significance to compensate the position of the motion platform through an external calibration system.

[0090] Among them, the method for obtaining a restored bitmap of the object to be detected based on the image and the target moving position corresponding to the current movement can be, first, determining the first coordinate system of the motion platform and the second coordinate system of the bitmap presentation plane, then determining the mapping relationship between the first coordinate system and the second coordinate system, and then converting the target moving position into the restored moving position based on the mapping relationship, and finally presenting the image at the restored moving position of 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 performing defect detection on the restored bitmap can be 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, or other reasonable methods for defect detection on the restored bitmap, which are not specifically limited here.

[0092] It can be understood that after the position measurement system compensates for the measured movement position of the object to be inspected, in addition to determining the position of the inspection image, restoring the MAP image, and other operations, other reasonable operations can also be performed to solve other wafer surface morphology detection and position determination needs, which are not limited here.

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

[0094] In this embodiment, after the motion platform is driven to move the object to be detected along the preset motion direction, the measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system can be obtained, and the deviation value corresponding to the current movement of the object to be detected in the preset motion direction can be predicted based on the preset difference curve, wherein the preset difference curve is used to characterize the measured deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction, and the target moving position corresponding to the current movement of the object to be detected in the preset motion direction can be determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the motion platform can be controlled to move based on the target moving position, so as to perform position compensation on the measured moving position of the object to be detected in the current movement measured by the position measurement system. Secondly, the interpolation algorithm (mathematical model) can be used to analyze the positioning compensation through a sufficiently large number of experimental data, thereby improving the accuracy of determining the cause of the deviation (error) and improving the accuracy and effectiveness of the position compensation. Next, the preset difference curve can be fitted based on the difference corresponding to each movement after the elimination process (i.e., the corrected data point), and the preset curve can be constructed through more accurate data estimation, thereby improving the accuracy of the prediction, and by interpolating the difference corresponding to each movement after the elimination process (i.e., the corrected data point), the actual change trend of the difference between the moving positions can be better reflected, so that a more accurate difference can be calculated between the moving positions for subsequent analysis and decision-making. Finally, the accuracy of the interferometer can reach the nanometer level, and calibration based on the interferometer can greatly improve the accuracy of the wafer movement position, thereby achieving the effect of high-precision compensation of the real-time position of the moving platform, so that the coordinate alignment, MAP map (bitmap) restoration, and defect position positioning can be guaranteed with high precision, thereby improving the authenticity and accuracy of the captured image and the accuracy of position coordinate restoration.

[0095] The above describes the motion platform position compensation method in the embodiment of the present application. The following describes the motion platform position compensation device in the embodiment of the present application. Figure 4 , one embodiment of the motion platform position compensation device in the embodiment of the present application includes:

[0096] An obtaining unit 401 is used to obtain a measured moving position corresponding to the current movement of the object to be detected in the preset moving direction measured by a position measurement system after the moving platform drives the object to be detected to move in the preset moving direction;

[0097] A 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 represent 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 moving along the preset movement direction;

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

[0099] In an embodiment of the present application, the motion platform can be driven to move the object to be detected along a preset motion direction, and the measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system can be obtained. The deviation value corresponding to the current movement of the object to be detected in the preset motion direction is predicted based on a preset difference curve, wherein the preset difference curve is used to characterize the measured deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction. The target moving position corresponding to the current movement of the object to be detected in the preset motion direction is determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the motion platform is controlled to move based on the target moving position to perform position compensation for the measured moving position of the current movement of the object to be detected measured by the position measurement system.

[0100] The following is a detailed description of the motion platform position compensation device in the embodiment of the present application, please refer to Figure 5 Another embodiment of the motion platform position compensation device in the embodiment of the present application includes:

[0101] An obtaining unit 501 is used to obtain a measured moving position corresponding to the current movement of the object to be detected in the preset moving direction measured by a position measurement system after the moving platform drives the object to be detected to move in the preset moving direction;

[0102] A 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 represent 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 moving along the preset movement direction;

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

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

[0105] A determination unit 504, configured to determine a target length;

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

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

[0108] The determining unit 504 is further used to determine a target length;

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

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

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

[0112] a removing unit 506, configured to remove the difference between the first moving position and the second moving position corresponding to the P-th movement if the difference between the first moving position and the second moving position exceeds a preset threshold range, and take the average of the difference p1 between the first moving position and the second moving position corresponding to the P-1-th movement and the difference p3 between the first moving position and the second moving position corresponding to the P+1-th movement as the difference p2 between the first moving position and the second moving position corresponding to the P-th movement, where P is an integer and P≥2;

[0113] The fitting unit 505 is specifically configured to obtain the preset difference curve based on the difference fitting corresponding to each movement after the elimination process by using an interpolation algorithm.

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

[0115] The trigger unit 507 is used to trigger the camera to take pictures according to the preset field of view if the 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 taken by at least one chip; a camera is installed in the Z-axis direction of the motion platform; the object to be detected includes N*M chips, N≥2, 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 acquisition 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 moving position into a restored moving position based on the mapping relationship, and present the image at the restored moving position on the bitmap presentation plane to obtain a 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 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 above Figure 1 The operation of the motion platform position compensation device in the illustrated embodiment will not be described in detail here.

[0121] See below Figure 6 Another embodiment of the motion platform position compensation device 600 in the embodiment of the present application includes:

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

[0123] The memory 605 is a temporary storage memory or a permanent storage memory;

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

[0125] The embodiment of the present application also provides a computer-readable storage medium, the computer-readable storage medium includes instructions, when the instructions are executed on a computer, the computer executes the aforementioned Figure 1 The method in the illustrated embodiment.

[0126] The present application also provides a computer program product including instructions, which, when executed on a computer, enables the computer to execute the aforementioned Figure 1 The method in the illustrated embodiment.

[0127] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

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

[0129] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

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

[0131] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0132] If the integrated unit is implemented in the form of 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 the present application is essentially 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, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk and other media that can store program code.

Claims

1. A motion platform position compensation method, characterized in that: include: After the motion platform is driven to move the object to be detected along the preset motion direction, a measured moving position corresponding to the current movement of the object to be detected in the preset motion direction measured by the position measurement system is obtained; Predicting the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on a preset difference curve; wherein the preset difference curve is used to characterize the measurement deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction; The target moving position corresponding to the current movement of the object to be detected in the preset movement direction is determined based on the deviation value corresponding to the current movement and the measured moving position corresponding to the current movement, and the movement of the motion platform is controlled based on the target moving position to perform position compensation for the measured moving position of the current movement of the object to be detected 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 target length; After driving the motion platform to move the object to be detected in sequence by the target length along the X-axis direction, the difference between the first moving position and the second moving position corresponding to each movement is obtained; wherein the first moving position corresponding to each movement is the first moving position corresponding to each movement 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 corresponding to each movement of the object to be detected in the X-axis direction measured by the calibration system; The preset difference curve is obtained by fitting based on the difference corresponding to each movement through an interpolation algorithm.

3. The method according to claim 1, characterized in that The object to be detected 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 target length; After driving the motion platform to move the object to be detected in sequence by the target length along the Y-axis direction, the difference between the first moving position and the second moving position corresponding to each movement is obtained; wherein the first moving position corresponding to each movement is the first moving position corresponding to each movement 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 corresponding to each movement of the object to be detected in the Y-axis direction measured by the calibration system; The preset difference curve is obtained by fitting based on the difference corresponding to each movement through an interpolation algorithm.

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

5. The method according to claim 1, characterized in that A camera is installed in the Z-axis direction of the motion platform; the object to be detected is a wafer, and the wafer includes N*M chips, N≥2, 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 the preset trigger condition is met, the camera is triggered to take a picture according to the preset field of view to obtain an 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; After determining the target movement position of the object to be detected corresponding to the current movement 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: A 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 a restored bitmap of the object to be detected based on the image and the target movement position corresponding to the current movement includes: Determine a first coordinate system of the motion platform and a second coordinate system of the bitmap presentation plane; Determine a mapping relationship between the first coordinate system and the second coordinate system; Converting the target moving position into a restored moving position based on the mapping relationship; The image is presented at the restored moved position of 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: Perform defect detection on the restored bitmap based on a preset standard image to obtain a detection result; or Defect detection is performed on the restored bitmap based on a defect detection algorithm to obtain a detection result.

8. A motion platform position compensation device, characterized in that: include: An obtaining unit, configured to obtain a measured moving position corresponding to the current movement of the object to be detected in the preset moving direction measured by the position measurement system after the moving platform drives the object to be detected to move in the preset moving direction; A prediction unit, used to predict the deviation value corresponding to the current movement of the object to be detected in the preset motion direction based on a preset difference curve; wherein the preset difference curve is used to characterize the measurement deviation between the actual moving position of the object to be detected measured by the position measurement system and the ideal moving position of the object to be detected moving along the preset motion direction; A position compensation unit is used to determine the target movement position corresponding to the current movement 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 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.

9. A motion platform position compensation device, characterized in that: include: CPU and memory; The memory is a transient 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 comprises instructions, and when the instructions are executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 7.

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