Wafer positioning method, device, equipment and medium

Abstract

The invention relates to the technical field of wafer detection, and provides a wafer positioning method, device and equipment and a storage medium, the method carries out circle fitting and straight line fitting through a plurality of contour point coordinates, the more the contour point coordinates participating in fitting are, the higher the positioning precision is, and parameter verification and correction can be carried out through multi-contour point fitting of a circle or a straight line. The precision of the fitting circle and the fitting straight line is higher; meanwhile, the image range for collecting the coordinates of the contour points can be very small, so that the image pixel precision is higher, the fitted circle center coordinates and positioning edge straight lines are more accurate, and the positioning precision and accuracy of the target wafer are improved.

Description

Technical Field

[0001] The present application relates to the field of wafer detection technology, and in particular to a wafer positioning method, device, computer equipment and storage medium. Background Art

[0002] Diffraction optical waveguides are cut from resin wafers, using 4-inch, 6-inch, and 8-inch wafers with diameters of 100.84mm, 152.4mm, and 203.2mm, respectively. Before cutting, the wafer needs to be coded, which requires the wafer to be positioned, and the positioning accuracy must be within 10μm.

[0003] Due to the large radius of the wafer, it is difficult to achieve an accuracy of less than 10μm using a global field of view. Therefore, existing wafer positioning methods usually use a local field of view image stitching method to position the wafer, that is, using the same image content in the two images for matching. Therefore, the two images captured by the acquisition system must have a certain amount of overlapping parts for image stitching.

[0004] However, the existing wafer positioning method requires overlapping content between the stitched pictures. To ensure overlapping content between the stitched pictures, one method is to have a sufficient field of view. A large field of view will lead to reduced positioning accuracy and inaccurate positioning. If a small field of view picture is collected to ensure positioning accuracy, the distance between the sampling points of different stitched pictures will be too small, resulting in poor wafer fitting effect and low positioning accuracy of the wafer center.

[0005] Therefore, how to improve wafer positioning accuracy has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The present application provides a wafer positioning method, device, equipment and storage medium, aiming to improve the accuracy of wafer positioning.

[0007] In a first aspect, the present application provides a wafer positioning method, comprising:

[0008] Based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform, fitting the center of the target wafer to determine the coordinates of the center of the target wafer;

[0009] Fitting the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer;

[0010] Based on the circle center coordinates and the current angle, a current position and posture of the target wafer on the mobile platform coordinate system is determined.

[0011] In a second aspect, the present application further provides a wafer positioning device, comprising:

[0012] A circle center fitting module, used to fit the circle center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform, and determine the coordinates of the circle center of the target wafer;

[0013] A wafer angle determination module, configured to fit the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform, and determine the current angle of the target wafer;

[0014] The wafer positioning module is used to determine the current position of the target wafer on the mobile platform coordinate system based on the center coordinates and the current angle.

[0015] In a third aspect, the present application also provides a computer device, comprising a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of the wafer positioning method as described above are implemented.

[0016] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the wafer positioning method as described above are implemented.

[0017] The present application provides a wafer positioning method, device, equipment and storage medium, the method comprising fitting the center of the target wafer based on at least three arc edge contour point coordinates of the arc edge contour of the target wafer in the mobile platform coordinate system, and determining the center coordinates of the target wafer; fitting the positioning edge straight line of the target wafer based on at least two positioning edge contour point coordinates of the positioning edge contour of the target wafer in the mobile platform coordinate system, and determining the current angle of the target wafer; based on the center coordinates and the current angle, determining the current posture of the target wafer in the mobile platform coordinate system. Through the above method, the present application performs circle fitting and straight line fitting through multiple contour point coordinates, the more contour point coordinates involved in fitting, the higher the positioning accuracy, and the multi-contour point fitting circle or straight line can also perform parameter verification and correction, so that the precision of the fitting circle and the fitting straight line is higher; at the same time, the image range of the contour point coordinates can be very small, so that the image pixel precision is higher, and then the fitting center coordinates and positioning edge straight line are more accurate, thereby improving the positioning precision and accuracy of the target wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of a process flow of a first embodiment of a wafer positioning method provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of a wafer outline structure provided in an embodiment of the present application;

[0021] Figure 3 A schematic diagram of a second embodiment of a wafer positioning method provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of the distribution of image acquisition points at a preset edge contour position of a target wafer provided in an embodiment of the present application;

[0023] Figure 5 It is a structural schematic diagram of a first embodiment of a wafer positioning device provided by the present application;

[0024] Figure 6 It is a schematic block diagram of the structure of a computer device provided in an embodiment of the present application.

[0025] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] The flowcharts shown in the accompanying drawings are only examples and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may also be decomposed, combined or partially merged, so the actual execution order may change according to actual conditions.

[0028] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] Please refer to Figure 1 , Figure 1 A schematic flow chart of a first embodiment of a wafer positioning method provided in an embodiment of the present application.

[0030] like Figure 1 As shown, the wafer positioning method includes steps S101 to S103.

[0031] S101, fitting the center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform to determine the coordinates of the center of the target wafer;

[0032] In one embodiment, a wafer refers to a silicon chip used to manufacture silicon semiconductor integrated circuits. Since it is round in shape, it is called a wafer. Figure 2 As shown, the wafer has a circular shape. At the same time, in order to facilitate positioning, the wafer also has a positioning edge. Therefore, the outer edge contour of the wafer can be divided into a circular arc edge contour and a straight positioning edge contour.

[0033] In one embodiment, the target wafer is fixedly mounted on a two-dimensional mobile platform during the positioning process, so the positioning process of the target wafer is a process of determining the posture of the target wafer in the mobile platform coordinate system where the two-dimensional mobile platform is located, including the physical coordinates of the center of the target wafer in the mobile platform coordinate system, and the deflection angle of the target wafer in the mobile platform coordinate system.

[0034] In one embodiment, the mobile platform coordinate system is a two-dimensional coordinate system, and the mobile platform can move bidirectionally on the mobile platform coordinate system (i.e., move along the X-axis direction and the Y-axis direction), and the center point of the mobile platform can be used as the coordinate positioning point of the mobile platform.

[0035] Exemplarily, the position of the center point of the mobile platform when the mobile platform is reset may be used as the coordinate origin of the mobile platform coordinate system, or the coordinate origin of the mobile platform coordinate system may be artificially defined.

[0036] In one embodiment, fitting is to connect a series of points on a plane with a smooth curve. At least three non-collinear points are required to define a triangle in two-dimensional space, so at least three points are required to define the circumscribed circle of a triangle in two-dimensional space, that is, at least three contour points are required to fit the circle.

[0037] In one embodiment, the physical coordinates of at least three contour points on the arc edge contour of the target wafer to be positioned in the mobile platform coordinate system are obtained, and a circle is fitted to the target wafer using the physical coordinates of the at least three contour points to calculate the coordinates of the center of the target wafer in the mobile platform coordinate system.

[0038] In one embodiment, the least square method may be used to perform circle fitting.

[0039] In one embodiment, the parametric equation of a circle is:

[0040] (X-X0) 2 +(Y-Y0) 2 =R 2 (1)

[0041] The principle of least squares method for fitting a circle is to find the coordinates of the center of the circle that minimizes the distance between the center of the fitted circle and the positions of the points to be fitted.

[0042] Assume that the number of contour points to be fitted in the contour point set is N, and the coordinates of each contour point are (X p , Y p ), where p ranges from 1 to N. The coordinates of the contour point whose X0, Y0 and R values ​​give the minimum value of equation (2) are the center coordinates of the target wafer.

[0043]

[0044]

[0045] in,

[0046] The X0, Y0 and R values ​​are obtained by the above formula (3) to obtain the center coordinates of the target wafer.

[0047] S102, fitting the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer;

[0048] In one embodiment, the calculation of the deflection angle of the target wafer may be determined based on the slope of the straight line where the positioning edge of the target wafer is located.

[0049] In one embodiment, for straight line fitting in two-dimensional space, fitting can be performed based on at least two points on the target straight line, that is, for fitting the straight line where the positioning edge of the target wafer is located, the coordinates of at least two contour points on the positioning edge contour in the mobile platform coordinate system are required.

[0050] Furthermore, at least one of the positioning edge contours and the coordinates of at least two of the positioning edge contour points on each of the positioning edge contours are obtained; based on a preset straight line fitting algorithm and the coordinates of at least two of the positioning edge contour points on each of the positioning edge contours, the positioning edge straight line is fitted and generated; based on the relative position relationship between the positioning edge straight line and the center of the target wafer, the current angle of the target wafer is determined.

[0051] In one embodiment, the straight line fitting algorithm may be a least square method, a Hough transform method, or the like.

[0052] In one embodiment, a straight line can be expressed in the form of y=bx+a, where b is the slope and a is the intercept. The least squares method fits n points so that the overall error of the points from the fitted straight line is as small as possible. The solution is to minimize the vertical error from each point to the straight line. After fitting the straight line, you can also select points that are closer to the straight line for re-fitting. After multiple times, you can get a straight line fitting result with higher accuracy.

[0053] Exemplarily, the least square method for fitting the positioning edge straight line can be used to calculate the slope and intercept of the straight line y=bx+a according to formula (4).

[0054]

[0055] Assuming the residual is e, we have:

[0056] y i =a*x i +b+e i (5)

[0057] Thus, the residual calculation formula can be obtained:

[0058] e i =y i -a*x i -b (6)

[0059] According to the above formula (6), find the residual sum of squares Q = ∑e i 2 The minimum a and b values ​​are obtained by taking the derivatives of a and b respectively, so that the two equations of the above formula (4) are 0 after the derivatives. Then the a and b values ​​can be obtained jointly, that is, the fitting straight line of the positioning edge can be obtained.

[0060] In one embodiment, the Hough transform is to count points by parameters, that is, based on known parameters and parameter ranges, use statistical ideas to determine the belonging of each point, directly count all points on all possible lines, and then vote to select the straight line with the highest number of votes as the fitting line.

[0061] In one embodiment, the deflection angle of the positioning edge in the mobile platform coordinate system can be obtained by fitting the linear slope of the positioning edge straight line of the target wafer, and then combined with the center coordinates of the target wafer, the deflection angle of the target wafer can be determined. For example, according to the center coordinates and the positioning edge straight line, the vertical line from the center of the circle to the positioning edge straight line can be calculated, and according to the slope of the vertical line, the deflection angle of the positioning edge relative to the center position can be determined, and the deflection angle can be used as the deflection angle of the target wafer in the mobile platform coordinate system.

[0062] In one embodiment, the positioning edge of the target wafer may be one or more. For example, the positioning edge of the target wafer may include a main positioning edge and a secondary positioning edge. The lengths of the main positioning edge and the secondary positioning edge may be inconsistent to make the deflection direction of the target wafer more accurate.

[0063] S103 . Determine a current position of the target wafer on the mobile platform coordinate system based on the circle center coordinates and the current angle.

[0064] In one embodiment, the current position of the target wafer can be determined based on the center coordinates of the target wafer in the coordinate system of the mobile platform and the current angle, thereby achieving positioning of the target wafer.

[0065] For example, the current center coordinates of the target wafer in the mobile platform coordinate system are (20, 34), and the deflection angle is -30°. When cutting the target wafer, the center coordinates of the target wafer need to be (40, 40) and the deflection angle is 0°. At this time, the current center coordinates and the current deflection angle of the target wafer can be adjusted so that its posture meets the cutting requirements.

[0066] Alternatively, the angle and position of operating equipment such as cutting tools may be adjusted according to the current posture of the target wafer, so that the relative posture (including relative position and relative angle) of the target wafer and the operating equipment can meet the operating requirements.

[0067] This embodiment provides a wafer positioning method, which performs circle fitting and straight line fitting through multiple contour point coordinates. The more contour point coordinates involved in the fitting, the higher the positioning accuracy. The multi-contour point fitting circle or straight line can also perform parameter verification and correction, so that the precision of the fitted circle and the fitted straight line is higher. At the same time, the image range for collecting contour point coordinates can be very small, so that the image pixel precision is higher, and then the fitted circle center coordinates and the positioning edge straight line are more precise, thereby improving the positioning precision and accuracy of the target wafer.

[0068] Please refer to Figure 3 , Figure 3 A schematic flow chart of a second embodiment of a wafer positioning method provided in an embodiment of the present application.

[0069] like Figure 3 As shown, based on the above Figure 1 In the illustrated embodiment, before step S101, the following steps are further included:

[0070] S201, using an image acquisition device to acquire an edge contour image at a preset edge contour position on the target wafer;

[0071] In one embodiment, the preset edge contour position on the target wafer may be a pre-marked edge contour position or a randomly collected edge contour position.

[0072] In one embodiment, the image acquisition device may include a camera, a scanner, or other device having image recognition and acquisition functions.

[0073] In one embodiment, the acquisition direction of the image acquisition device is perpendicular to the two-dimensional plane where the mobile platform is located.

[0074] In one embodiment, the image acquisition device can be fixedly installed above the mobile platform, and the mobile platform drives the target wafer to move on the two-dimensional platform surface, so that the edge contour position of the target wafer is moved to the acquisition screen of the image acquisition device. The image acquisition device can also be installed on a three-dimensional mobile platform, so that the image acquisition device can move in three directions of X, Y, and Z axes. Among them, the plane where the X and Y axes of the three-dimensional mobile platform are located is parallel to the two-dimensional plane where the mobile platform is located, and the Z axis is perpendicular to the two-dimensional plane where the mobile platform is located. The image acquisition device can also be installed on a device that can move along the Z axis direction, such as a pneumatic slide bar, a mechanical slide bar, etc., so that the image acquisition device can move along the Z axis direction to adjust the acquisition screen size of the image acquisition device, that is, the acquisition accuracy.

[0075] In one embodiment, the mobile platform can be driven to move in the mobile platform coordinate system so that the preset edge contour position of the target wafer is moved below the image acquisition device, and then the edge contour image of the preset edge contour position is acquired by the image acquisition device.

[0076] In one embodiment, the image acquisition device may be driven to move to a preset edge contour position of the target wafer to acquire an edge contour image at the preset edge contour position.

[0077] In one embodiment, to ensure the image acquisition effect, a panel light source can be set under the target wafer for back lighting. To improve the measurement accuracy, a high-resolution image acquisition device can be used, such as a camera with a resolution of 2448×2048.

[0078] It can be understood that when the resolution of the image acquisition device is fixed, the smaller the field of view of the acquisition screen, the smaller the actual size corresponding to a single pixel in the acquisition screen, that is, the higher the single pixel accuracy. Therefore, the image acquisition device can be equipped with a telecentric lens to improve the measurement accuracy, further reduce the field of view of the image acquisition device, and thus improve the single pixel accuracy of the image acquisition device. For example, a camera with a resolution of 2448×2048 and a field of view of 8.4mm*7.1mm has a single pixel accuracy of 0.003mm, which can meet the accuracy requirements of wafer marking.

[0079] In one embodiment, the edge contour image includes an arc edge contour image and a positioning edge contour image; when the image acquisition device acquires the edge contour image, the absolute coordinates of the mobile platform in the mobile platform coordinate system are obtained to determine the first mobile platform coordinates corresponding to the arc edge contour image and the second mobile platform coordinates corresponding to the positioning edge contour image.

[0080] In one embodiment, the wafer is circular, but the wafer also has a direction, and the direction of the wafer is determined based on the positioning edge. Therefore, when positioning the wafer, it is necessary to determine the center coordinates of the wafer and determine the angle of the wafer based on the positioning edge, thereby determining the position information of the wafer based on the center coordinates and the angle.

[0081] In one embodiment, the outer contour of the wafer is circular, and the positioning edge is linear, so the edge contour of the wafer includes an arc contour and a linear contour. There are two types of edge contour images of the target wafer collected by the image acquisition device, namely, an arc edge contour image including an arc contour and a positioning edge contour image including a linear contour.

[0082] In one embodiment, the image acquisition device acquires edge contour images at different preset edge contour positions of the target wafer, so the mobile platform coordinates corresponding to each preset edge contour position are not the same. When the image acquisition device acquires edge contour images, the two-dimensional coordinates of the mobile platform carrying the target wafer in the mobile platform coordinate system when acquiring each frame of edge contour images can be simultaneously recorded. For the arc edge contour image and the positioning edge contour image, they can be recorded as the first mobile platform coordinates corresponding to the arc edge contour image and the second mobile platform coordinates corresponding to the positioning edge contour image, respectively, so as to facilitate the subsequent conversion of the pixel coordinates of the contour points on each edge contour in the edge contour image into the absolute coordinates in the mobile platform coordinate system.

[0083] The absolute coordinates refer to the coordinates of each contour point on the target wafer in the mobile platform coordinate system relative to the origin of the mobile platform coordinate system.

[0084] In one embodiment, the preset edge contour position includes an arc edge contour position, and the arc edge contour position includes one or more.

[0085] In one embodiment, when the arc edge contour position includes a plurality of positions, the arc edge contour position is determined on the target wafer based on a preset interval angle.

[0086] In one embodiment, the edge contour position of the target wafer includes a circular contour edge, and for the circular contour fitting of the target wafer, it is necessary to collect the contour point coordinates on the circular contour edge. The fitting circle requires at least three non-collinear point coordinates, so the contour points are collected from the contour position of the arc edge of the target wafer.

[0087] In one embodiment, the edge contour image captured by the image acquisition device is a regional image, and the image obtained is an image of a segment of an arc on the circular contour edge of the target wafer. Therefore, there are many contour points that can be collected on the edge contour image. Therefore, the arc edge contour position may include one or more, that is, the image acquisition device can collect one or more frames of images at an arc edge contour position on the target wafer to collect contour points, and can also collect one or more frames of images at multiple different arc edge contour positions on the target wafer to collect contour points.

[0088] In one embodiment, when the arc edge contour position is one, the image acquisition device acquires the arc contour at the arc edge contour position, and then acquires at least three points on the arc contour to perform circular contour fitting of the target wafer, and then determines the center coordinates of the target wafer.

[0089] In one embodiment, when there are multiple arc edge contour positions, arc contour images can be collected at different edge contour positions on the target wafer, and the more uniform the distribution of edge contour positions and the more data collected, the more accurate the result of fitting the circle.

[0090] Furthermore, at least one of the arc edge contours and at least three arc edge contour point coordinates on each of the arc edge contours are obtained; based on the at least three arc edge contour point coordinates on each of the arc edge contours, the fitting center of the target wafer corresponding to each of the arc edge contours is fitted respectively; based on the distance error between each of the fitting center of the circle and each of the arc edge contours, the center of the target wafer is determined from each of the fitting center of the circle to obtain the center coordinates.

[0091] Exemplarily, to facilitate understanding by those skilled in the art, the embodiment of the present application is described using three edge contour positions as an example, but the present application only uses this embodiment as an example and does not constitute a limitation on data such as the number of edge contour positions and acquisition positions.

[0092] In one embodiment, if Figure 4 As shown, Figure 4 A schematic diagram of the sampling point position of the target wafer edge contour position provided in an embodiment of the present application. Three arc edge contour positions (such as position 1, position 2 and position 3) for collecting arc edge contour images can be preset to locate the center coordinates of the target wafer.

[0093] In one embodiment, position 1, position 2 and position 3 may be three randomly selected non-overlapping arc edge contour positions. In order to improve the accuracy of the circle fitting result, the three arc edge contour positions may also be specified, that is, the preset interval angles of the three arc edge contour positions are limited.

[0094] In one embodiment, the preset interval angle may be 120°. Because the target wafer is circular, the preset interval angle of 120° can make the three arc edge contour positions evenly distributed on the circular contour of the target wafer. At this time, the effect of fitting the circle is the best and the accuracy is the highest. The arc edge contour images of the three arc edge contour positions are collected, and then the contour points on each arc edge contour image are selected for circle fitting.

[0095] In one embodiment, the preset interval angle may also be a range. For example, when the angle deviation range is about 20° to ensure the accuracy requirement, the interval angles of the three arc edge contour positions may be 100°, 140°, and 120°, respectively.

[0096] In one embodiment, at least one contour point can be selected and merged on each of the arc edge contour images corresponding to the three arc edge contour positions to obtain a contour point set, and then the circular contour of the target wafer is fitted based on the coordinates of at least three contour points in the contour point set.

[0097] In one embodiment, at least three contour points can be selected on each of the arc edge contour images corresponding to the three arc edge contour positions, and then contour point sets corresponding to each arc edge contour image are constructed respectively, and then circle fitting is performed according to the contour point sets corresponding to each arc edge contour image, that is, three fitting circles are obtained, and then one of the center coordinates of the three fitting circles is selected as the center coordinate of the target wafer.

[0098] For example, the position residuals of the center coordinates of the three fitted circles from the contours of each arc edge can be calculated respectively, and the center coordinates of the fitted circle with the smallest position residual are used as the center coordinates of the target wafer.

[0099] In one embodiment, the preset edge contour includes a positioning edge contour, and the positioning edge contour includes one or more.

[0100] Continue as Figure 4 As shown, two arc edge contour positions (such as position 4 and position 5) for collecting positioning edge contour images can be preset to locate the angle of the target wafer.

[0101] In one embodiment, position 4 and position 5 may be two randomly selected non-overlapping positioning edge contour positions. At least two contour point coordinates may be collected from the positioning edge contour image collected at position 4 or position 5 to fit the positioning edge straight line. At least two contour point coordinates may also be collected from the positioning edge contour images collected at two positions to fit the positioning edge straight line.

[0102] S202, extracting the edge contour of the edge contour image and the contour point pixel coordinates of each contour point on the edge contour based on an image processing algorithm to obtain an edge contour pixel coordinate set;

[0103] In one embodiment, the edge contour pixel coordinate set includes an arc edge contour pixel coordinate set and a positioning edge contour pixel coordinate set.

[0104] In one embodiment, the contour points on the arc edge contour in the arc edge contour image are used to locate the center coordinates of the target wafer, and the contour points on the positioning edge contour of the positioning edge contour image are suitable for locating the angle of the target wafer. Therefore, the pixel coordinates of the contour points on the arc edge contour constitute an arc edge contour pixel coordinate set, and the pixel coordinates of the contour points on the positioning edge contour constitute a positioning edge contour pixel coordinate set, which are respectively used to fit the circular contour and the positioning edge straight line of the target wafer.

[0105] In one embodiment, the image processing algorithm may be an edge detection algorithm. The edge detection method relies on the calculation of image gradients, and uses different types of filters to estimate the gradients in the x-direction and y-direction, thereby obtaining the gradient coordinates of the image features in the image.

[0106] Generally, edge detection methods can be roughly divided into two categories: search-based and zero-crossing-based.

[0107] Among them, the search-based edge detection method first calculates the edge strength, usually expressed as a first-order derivative, such as the gradient modulus; then, the local direction of the edge is estimated by calculation, usually using the direction of the gradient, and this direction is used to find the maximum value of the local gradient modulus.

[0108] Zero-crossing based methods find the zero-crossing points of the second-order derivative obtained from the image to locate the edge. Usually the zero-crossing points of the Laplace operator or nonlinear differential equations are used.

[0109] Generally, the edge detection algorithm includes an image preprocessing process and a detection process, and its steps may include:

[0110] ① Filtering: The edge detection algorithm is mainly based on the first and second order derivatives of image intensity, but the calculation of derivatives is very sensitive to noise, so filters must be used to improve the performance of edge detectors related to noise.

[0111] ② Enhancement: The basis of edge enhancement is to determine the change value of the neighborhood intensity of each point in the image. The enhancement algorithm can highlight the points with significant changes in neighborhood (or local) intensity values.

[0112] ③Detection: There are many points in the image with large gradient amplitudes, but these points are not all edges in specific application fields, so some method should be used to determine which points are edge points.

[0113] ④ Positioning: If an application requires the determination of the edge position, the edge position can be estimated at sub-pixel resolution, and the orientation of the edge can also be estimated.

[0114] Exemplarily, the processing process of the edge contour image by the image processing algorithm may include: using the automatically determined image segmentation threshold to segment a single-channel gray value image (wherein, the process of determining the image segmentation threshold includes: first, determining the relative histogram of the image gray value; then, extracting the relevant minimum value from the histogram as a parameter of the threshold segmentation operation); obtaining the connected domain of the segmented area, and screening out the corresponding target area by area and length, and this area is the edge to be detected; performing regional expansion processing on the target area; performing regional erosion processing on the target area; subtracting the expanded area from the eroded area, and performing a cutout processing (the purpose is to obtain a real image with an edge, in preparation for the next step of processing); using an edge detection method to extract sub-pixel contours, and synchronously obtaining the pixel coordinate points of the sub-pixel contours.

[0115] S203 . Based on a coordinate conversion algorithm, convert the contour point pixel coordinates in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system to obtain an edge contour point coordinate set.

[0116] The edge contour point coordinate set includes an arc edge contour point coordinate set and a positioning edge contour point coordinate set, the arc edge contour point coordinate set includes at least three arc edge contour point coordinates, and the positioning edge contour point coordinate set includes at least two positioning edge contour point coordinates.

[0117] In one embodiment, when the image acquisition device acquires edge contour images, the coordinates of the mobile platform in the mobile platform coordinate system when each edge contour image is acquired can be synchronously recorded to facilitate converting the pixel coordinates of the contour points in each edge contour image into absolute coordinates in the mobile platform coordinate system.

[0118] In one embodiment, the pixel coordinates of the contour points in the edge contour pixel coordinate set are converted into absolute coordinates in the mobile platform coordinate system by a coordinate conversion algorithm. The edge contour pixel coordinate set includes an arc edge contour pixel coordinate set and a positioning edge contour pixel coordinate set. Accordingly, the pixel coordinates in the arc edge contour pixel coordinate set and the positioning edge contour pixel coordinate set are converted by a coordinate conversion algorithm to obtain an arc edge contour point coordinate set and a positioning edge contour point coordinate set.

[0119] Furthermore, the image center coordinates of the image center of the edge contour image in the mobile platform coordinate system are obtained; based on the coordinate conversion algorithm, the image center coordinates and the first mobile platform coordinates, the contour point pixel coordinates in the arc edge contour pixel coordinate set are converted into the absolute coordinates to obtain the arc edge contour point coordinate set; based on the coordinate conversion algorithm, the image center coordinates and the second mobile platform coordinates, the contour point pixel coordinates in the positioning edge contour pixel coordinate set are converted into the absolute coordinates to obtain the positioning edge contour point coordinate set.

[0120] In one embodiment, the pixel coordinates of the contour points in the image coordinate system are converted into absolute coordinates in the mobile platform coordinate system through coordinate transformation, and coordinate synchronization needs to be achieved based on the point coordinates of the reference point in the two coordinate systems. The two-dimensional coordinates (X, Y axis coordinates) of the image acquisition device in the mobile platform coordinate system can be set, and the position (i.e., height and angle) of the image acquisition device for each acquisition of the edge contour image is fixed, and the parameters used (resolution, telecentric lens, etc.) are the same to ensure that the size of the acquisition area is consistent each time. At this time, the image center of the edge contour image acquired by the image acquisition device can be used as a reference point. The coordinates of the image center of the edge contour image in the mobile platform coordinate system are constant, and the resolution of the edge contour image is also constant. Therefore, based on the resolution, field of view size and focal length of the edge contour image, the single pixel accuracy of the edge contour image can be calculated. For example, for a camera with a resolution of 2448×2048 and a field of view of 8.4mm*7.1mm, the single pixel accuracy is 0.003mm.

[0121] In one embodiment, the movement of the mobile platform can be controlled to move the center point (marker point) of the mobile platform into the field of view of the image acquisition device, and the center point of the mobile platform is adjusted to coincide with the center of the acquisition screen of the image acquisition device. At this time, the coordinates of the mobile platform in the mobile platform coordinate system are read, which are the absolute coordinates of the center point of the acquisition screen of the image acquisition device in the mobile platform coordinate system, that is, the image center coordinates of the edge contour image in the mobile platform coordinate system.

[0122] In one embodiment, a two-dimensional mobile platform carrying a wafer can be moved (the mobile platform can move in both X and Y directions), such as Figure 4As shown, the image acquisition system can acquire the arc edge contour image of the target wafer at position 1, position 2, and position 3 respectively. When acquiring the arc edge contour image at position 1, the coordinates of the X / Y mobile platform are (X1, Y1), when acquiring the arc edge contour image at position 2, the coordinates of the X / Y mobile platform are (X2, Y2), and when acquiring the arc edge contour image at position 3, the coordinates of the X / Y mobile platform are (X3, Y3). The pixel coordinates of the contour points in the arc edge contour images corresponding to the three positions are transformed to obtain the physical coordinate point set (Row1, Col1) of position 1, the physical coordinate point set of the image acquired at position 2 is (Row2+(X2-X1), Col2+(Y2-Y1)), and the physical coordinate point set of the image acquired at position 3 is (Row3+(X3-X1), Col2+(Y3-Y1)). The physical coordinate points obtained at positions 1, 2, and 3 are merged together to obtain the contour point sets (CircleRow, CircleCol) of the three arc edge contour positions.

[0123] In one embodiment, continue as Figure 4 As shown, position 4 and position 5 are the preset edge contour positions of the positioning edge contour. Move the X / Y mobile platform carrying the wafer, and the image acquisition device can collect the positioning edge contour image of the target wafer at position 4 and position 5 respectively. When collecting the positioning edge contour image at position 4, the coordinates of the X / Y mobile platform are (X4, Y4), and when collecting position 5, the coordinates of the X / Y mobile platform are (X5, Y5). Similarly, the physical coordinate point of position 4 (Row4+X4, Col4+Y4) is calculated by the image processing algorithm and the coordinate conversion algorithm, and the physical coordinate point of the image collected at position 5 is (Row5+(X5-X4), Col5+(Y5-Y4)). The physical coordinate points obtained at position 4 and position 5 are merged together to obtain the total contour point set (LineRow, LineCol) of the two positioning edge contour positions.

[0124] In this embodiment, the edge contour image of the target wafer is captured by an image acquisition device, and a small field of view is captured by high-resolution images to improve the image pixel accuracy, thereby improving the acquisition accuracy of the target wafer contour point coordinates, and further making the absolute coordinates of the contour points obtained by converting the contour point pixel coordinates in the mobile platform coordinate system more accurate, so that the fitting results of the circle fitting and the straight line fitting based on the contour point coordinates are more accurate, and the positioning of the center coordinates of the target wafer and the positioning edge straight line is more accurate.

[0125] See also Figure 5 , Figure 5 It is a structural schematic diagram of a first embodiment of a wafer positioning device provided in the present application, and the wafer positioning device is used to execute the aforementioned wafer positioning method.

[0126] like Figure 5 As shown, the wafer positioning device 400 includes: a circle center fitting module 401 , a wafer angle determination module 402 and a wafer positioning module 403 .

[0127] The center fitting module 401 is used to fit the center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform to determine the coordinates of the center of the target wafer;

[0128] The wafer angle determination module 402 is used to fit the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer;

[0129] The wafer positioning module 403 is used to determine the current position of the target wafer on the mobile platform coordinate system based on the center coordinates and the current angle.

[0130] In one embodiment, the wafer positioning device 400 further includes a contour point coordinate acquisition module, and the contour point coordinate acquisition module includes:

[0131] An edge contour image acquisition unit, used for acquiring an edge contour image of a preset edge contour position on the target wafer based on an image acquisition device;

[0132] An image processing unit is used to extract the edge contour of the edge contour image and the contour point pixel coordinates of each contour point on the edge contour based on an image processing algorithm to obtain an edge contour pixel coordinate set;

[0133] A coordinate conversion unit is used to convert the contour point pixel coordinates in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system based on a coordinate conversion algorithm to obtain an edge contour point coordinate set; wherein the edge contour point coordinate set includes an arc edge contour point coordinate set and a positioning edge contour point coordinate set, the arc edge contour point coordinate set includes at least three arc edge contour point coordinates, and the positioning edge contour point coordinate set includes at least two positioning edge contour point coordinates.

[0134] In one embodiment, the preset edge contour position includes an arc edge contour position, and the arc edge contour position includes one or more;

[0135] The contour point coordinate acquisition module also includes:

[0136] The arc edge contour position determining unit is used to determine the arc edge contour position on the target wafer based on a preset interval angle when the arc edge contour position includes multiple arc edge contour positions.

[0137] In one embodiment, the circle center fitting module 401 includes:

[0138] An arc edge contour acquisition unit, used to acquire at least one of the arc edge contours and at least three arc edge contour point coordinates on each of the arc edge contours;

[0139] A circle center fitting unit, used for fitting the circle center of the target wafer corresponding to each of the arc edge contours based on the coordinates of at least three arc edge contour points on each of the arc edge contours;

[0140] The center coordinate determining unit is used to determine the center of the target wafer from each of the fitting centers based on the distance error between each of the fitting centers and each of the arc edge contours, so as to obtain the center coordinates.

[0141] In one embodiment, the edge contour image includes an arc edge contour image and a positioning edge contour image;

[0142] The contour point coordinate acquisition module also includes:

[0143] The absolute coordinate reading unit is used to obtain the absolute coordinates of the mobile platform in the mobile platform coordinate system when the image acquisition device acquires the edge contour image, and to determine the first mobile platform coordinates corresponding to the arc edge contour image and the second mobile platform coordinates corresponding to the positioning edge contour image.

[0144] In one embodiment, the edge contour pixel coordinate set includes an arc edge contour pixel coordinate set and a positioning edge contour pixel coordinate set;

[0145] The coordinate conversion unit comprises:

[0146] An image center coordinate acquisition subunit, used to acquire the image center coordinates of the image center of the edge contour image in the mobile platform coordinate system;

[0147] A first coordinate conversion subunit is used to convert the contour point pixel coordinates in the arc edge contour pixel coordinate set into the absolute coordinates based on the coordinate conversion algorithm, the image center coordinates and the first mobile platform coordinates to obtain the arc edge contour point coordinate set;

[0148] The second coordinate conversion subunit is used to convert the contour point pixel coordinates in the positioning edge contour pixel coordinate set into the absolute coordinates based on the coordinate conversion algorithm, the image center coordinates and the second mobile platform coordinates to obtain the positioning edge contour point coordinate set.

[0149] In one embodiment, the preset edge profile includes a positioning edge profile, and the positioning edge profile includes one or more;

[0150] The wafer angle determination module 402 includes:

[0151] A positioning edge contour acquisition unit, used to acquire at least one positioning edge contour and at least two positioning edge contour point coordinates on each positioning edge contour;

[0152] A positioning edge straight line fitting unit, used for fitting and generating the positioning edge straight line based on a preset straight line fitting algorithm and the coordinates of at least two positioning edge contour points on each positioning edge contour;

[0153] The current angle determination unit is used to determine the current angle of the target wafer based on the relative position relationship between the positioning edge straight line and the center of the target wafer.

[0154] It should be noted that those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the above-described device and each module can refer to the corresponding process in the aforementioned wafer positioning method embodiment, and will not be repeated here.

[0155] The apparatus provided in the above embodiment may be implemented in the form of a computer program. The computer program may be Figure 6 Runs on the computer device shown.

[0156] See also Figure 6 , Figure 6 1 is a schematic block diagram of a computer device provided in an embodiment of the present application. The computer device may be a server.

[0157] See also Figure 6 The computer device includes a processor, a memory and a network interface connected through a system bus, wherein the memory may include a non-volatile storage medium and an internal memory.

[0158] The non-volatile storage medium can store an operating system and a computer program. The computer program includes program instructions, and when the program instructions are executed, the processor can execute any wafer positioning method.

[0159] The processor is used to provide computing and control capabilities and support the operation of the entire computer equipment.

[0160] The internal memory provides an environment for the operation of the computer program in the non-volatile storage medium. When the computer program is executed by the processor, the processor can execute any wafer positioning method.

[0161] The network interface is used for network communication, such as sending assigned tasks, etc. Those skilled in the art will understand that Figure 6The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0162] It should be understood that the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Among them, the general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0163] In one embodiment, the processor is used to run a computer program stored in the memory to implement the following steps:

[0164] Based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform, fitting the center of the target wafer to determine the coordinates of the center of the target wafer;

[0165] Fitting the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer;

[0166] Based on the circle center coordinates and the current angle, a current position and posture of the target wafer on the mobile platform coordinate system is determined.

[0167] In one embodiment, before implementing the coordinates of at least three arc edge contour points based on the arc edge contour of the target wafer in the coordinate system of the mobile platform, fitting the center of the target wafer, and determining the coordinates of the center of the target wafer, the processor is further used to implement:

[0168] Based on the image acquisition device, an edge contour image of a preset edge contour position on the target wafer is acquired;

[0169] Based on an image processing algorithm, extract the edge contour of the edge contour image and the contour point pixel coordinates of each contour point on the edge contour to obtain an edge contour pixel coordinate set;

[0170] Based on a coordinate conversion algorithm, the pixel coordinates of the contour points in the edge contour pixel coordinate set are converted into absolute coordinates in the mobile platform coordinate system to obtain an edge contour point coordinate set;

[0171] The edge contour point coordinate set includes an arc edge contour point coordinate set and a positioning edge contour point coordinate set, the arc edge contour point coordinate set includes at least three arc edge contour point coordinates, and the positioning edge contour point coordinate set includes at least two positioning edge contour point coordinates.

[0172] In one embodiment, the preset edge contour position includes an arc edge contour position, and the arc edge contour position includes one or more;

[0173] Before the processor implements the acquisition of the edge contour image at the preset edge contour position on the target wafer based on the image acquisition device, the processor is further used to implement:

[0174] When the arc edge contour position includes a plurality of positions, the arc edge contour position is determined on the target wafer based on a preset interval angle.

[0175] In one embodiment, when the processor implements the coordinates of at least three arc edge contour points based on the arc edge contour of the target wafer in the coordinate system of the mobile platform, fits the center of the target wafer, and determines the coordinates of the center of the target wafer, it is used to implement:

[0176] Obtaining at least one of the arc edge contours and at least three arc edge contour point coordinates on each of the arc edge contours;

[0177] Based on the coordinates of at least three arc edge contour points on each of the arc edge contours, fitting the fitting center of the target wafer corresponding to each of the arc edge contours respectively;

[0178] Based on the distance error between each fitting circle center and each arc edge contour, the center of the target wafer is determined from each fitting circle center to obtain the circle center coordinates.

[0179] In one embodiment, the edge contour image includes an arc edge contour image and a positioning edge contour image;

[0180] Before the processor implements the coordinate conversion algorithm to convert the contour point pixel coordinates in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system to obtain the edge contour point coordinate set, the processor is further used to implement:

[0181] When the image acquisition device acquires the edge contour image, the absolute coordinates of the mobile platform in the mobile platform coordinate system are obtained to determine the first mobile platform coordinates corresponding to the arc edge contour image and the second mobile platform coordinates corresponding to the positioning edge contour image.

[0182] In one embodiment, the edge contour pixel coordinate set includes an arc edge contour pixel coordinate set and a positioning edge contour pixel coordinate set;

[0183] When the processor implements the coordinate conversion algorithm to convert the contour point pixel coordinates in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system to obtain the edge contour point coordinate set, it is used to implement:

[0184] Obtaining the image center coordinates of the image center of the edge contour image in the mobile platform coordinate system;

[0185] Based on the coordinate conversion algorithm, the image center coordinates and the first mobile platform coordinates, the contour point pixel coordinates in the arc edge contour pixel coordinate set are converted into the absolute coordinates to obtain the arc edge contour point coordinate set;

[0186] Based on the coordinate conversion algorithm, the image center coordinates and the second mobile platform coordinates, the contour point pixel coordinates in the positioning edge contour pixel coordinate set are converted into the absolute coordinates to obtain the positioning edge contour point coordinate set.

[0187] In one embodiment, the preset edge profile includes a positioning edge profile, and the positioning edge profile includes one or more;

[0188] When the processor implements fitting the positioning edge straight line of the target wafer based on the at least two positioning edge contour point coordinates of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer, it is used to implement:

[0189] Acquire at least one of the positioning edge contours and at least two of the positioning edge contour point coordinates on each of the positioning edge contours;

[0190] Based on a preset straight line fitting algorithm and the coordinates of at least two positioning edge contour points on each positioning edge contour, fitting and generating the positioning edge straight line;

[0191] Based on the relative position relationship between the positioning edge straight line and the center of the target wafer, the current angle of the target wafer is determined.

[0192] A computer-readable storage medium is also provided in an embodiment of the present application. The computer-readable storage medium stores a computer program. The computer program includes program instructions. The processor executes the program instructions to implement any wafer positioning method provided in the embodiment of the present application.

[0193] The computer-readable storage medium may be an internal storage unit of the computer device described in the above embodiment, such as a hard disk or memory of the computer device. The computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a smart memory card (SmartMediaCard, SMC), a secure digital (SecureDigital, SD) card, a flash card (FlashCard), etc. equipped on the computer device.

[0194] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A wafer positioning method, characterized in that: The method comprises: Based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform, fitting the center of the target wafer to determine the coordinates of the center of the target wafer; Fitting the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer; Based on the circle center coordinates and the current angle, a current position and posture of the target wafer on the mobile platform coordinate system is determined.

2. The wafer positioning method according to claim 1, characterized in that: Before fitting the center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform and determining the coordinates of the center of the target wafer, the method further includes: Based on the image acquisition device, an edge contour image of a preset edge contour position on the target wafer is acquired; Based on an image processing algorithm, extract the edge contour of the edge contour image and the contour point pixel coordinates of each contour point on the edge contour to obtain an edge contour pixel coordinate set; Based on a coordinate conversion algorithm, the pixel coordinates of the contour points in the edge contour pixel coordinate set are converted into absolute coordinates in the mobile platform coordinate system to obtain an edge contour point coordinate set; The edge contour point coordinate set includes an arc edge contour point coordinate set and a positioning edge contour point coordinate set, the arc edge contour point coordinate set includes at least three arc edge contour point coordinates, and the positioning edge contour point coordinate set includes at least two positioning edge contour point coordinates.

3. The wafer positioning method according to claim 2, characterized in that: The preset edge contour position includes an arc edge contour position, and the arc edge contour position includes one or more; Before acquiring the edge contour image of the preset edge contour position on the target wafer based on the image acquisition device, the method further includes: When the arc edge contour position includes a plurality of positions, the arc edge contour position is determined on the target wafer based on a preset interval angle.

4. The wafer positioning method according to claim 3, characterized in that: The method of fitting the center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform to determine the coordinates of the center of the target wafer includes: Obtaining at least one of the arc edge contours and at least three arc edge contour point coordinates on each of the arc edge contours; Based on the coordinates of at least three arc edge contour points on each of the arc edge contours, fitting the fitting center of the target wafer corresponding to each of the arc edge contours respectively; Based on the distance error between each fitting circle center and each arc edge contour, the center of the target wafer is determined from each fitting circle center to obtain the circle center coordinates.

5. The wafer positioning method according to claim 2, characterized in that: The edge contour image includes an arc edge contour image and a positioning edge contour image; The step of converting the pixel coordinates of the contour points in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system based on a coordinate conversion algorithm, before obtaining the edge contour point coordinate set, further comprises: When the image acquisition device acquires the edge contour image, the absolute coordinates of the mobile platform in the mobile platform coordinate system are obtained to determine the first mobile platform coordinates corresponding to the arc edge contour image and the second mobile platform coordinates corresponding to the positioning edge contour image.

6. The wafer positioning method according to claim 5, characterized in that: The edge contour pixel coordinate set includes an arc edge contour pixel coordinate set and a positioning edge contour pixel coordinate set; The step of converting the pixel coordinates of the contour points in the edge contour pixel coordinate set into absolute coordinates in the mobile platform coordinate system based on a coordinate conversion algorithm to obtain the edge contour point coordinate set includes: Obtaining the image center coordinates of the image center of the edge contour image in the mobile platform coordinate system; Based on the coordinate conversion algorithm, the image center coordinates and the first mobile platform coordinates, the contour point pixel coordinates in the arc edge contour pixel coordinate set are converted into the absolute coordinates to obtain the arc edge contour point coordinate set; Based on the coordinate conversion algorithm, the image center coordinates and the second mobile platform coordinates, the contour point pixel coordinates in the positioning edge contour pixel coordinate set are converted into the absolute coordinates to obtain the positioning edge contour point coordinate set.

7. The wafer positioning method according to claim 2, characterized in that: The preset edge contour includes a positioning edge contour, and the positioning edge contour includes one or more; The method of fitting the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform to determine the current angle of the target wafer includes: Acquire at least one of the positioning edge contours and at least two of the positioning edge contour point coordinates on each of the positioning edge contours; Based on a preset straight line fitting algorithm and the coordinates of at least two positioning edge contour points on each positioning edge contour, fitting and generating the positioning edge straight line; Based on the relative position relationship between the positioning edge straight line and the center of the target wafer, the current angle of the target wafer is determined.

8. A wafer positioning device, characterized in that: The wafer positioning device comprises: A circle center fitting module, used to fit the circle center of the target wafer based on the coordinates of at least three arc edge contour points of the arc edge contour of the target wafer in the coordinate system of the mobile platform, and determine the coordinates of the circle center of the target wafer; A wafer angle determination module, configured to fit the positioning edge straight line of the target wafer based on the coordinates of at least two positioning edge contour points of the positioning edge contour of the target wafer in the coordinate system of the mobile platform, and determine the current angle of the target wafer; The wafer positioning module is used to determine the current position of the target wafer on the mobile platform coordinate system based on the center coordinates and the current angle.

9. A computer device, characterized in that: The computer device includes a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of the wafer positioning method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the steps of the wafer positioning method according to any one of claims 1 to 7 are implemented.

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