Wafer positioning method and device

Abstract

The present application relates to a wafer positioning method and device, the method comprising: moving a moving stage to a teaching position and recording its calibration position coordinates and rotation angle; using an image acquisition device to acquire characteristic marks of a calibration plate placed on the moving stage and images at different rotation axis angles, so as to obtain a mapping relationship between a pixel coordinate system and a world coordinate system, and to acquire edge images of products to be positioned at different rotation axis angles; the calibration plate at different rotation axis angles and edge images of products to be positioned are acquired by rotating the moving stage at a calibration rotation angle amplitude; acquiring the position coordinates of the edge in the world coordinate system and the center position coordinates of the products to be positioned based on the mapping relationship; acquiring the contour information of the positioning mark on the products to be positioned, and acquiring the position coordinates of the positioning mark based on the mapping relationship. The use of this method can effectively improve the alignment accuracy of wafers.

Description

Technical Field

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

[0002] In the semiconductor industry, wafer production is mostly round wafers. The robot in the mechanical module takes the wafer out of the wafer box and places it on the alignment platform. After alignment, the robot sends the wafer to the processing platform. After the wafer is placed on the alignment platform, the center of the wafer will deviate from the center of the platform, and there will be deviations in the Notch position on the wafer. If positioning and calibration are not performed in time, the processing accuracy will be reduced, affecting subsequent processes and even causing the wafer to be scrapped. Therefore, in the semiconductor process, there are certain requirements for the center deviation and Notch position of the wafer, that is, product posture positioning is required.

[0003] Product positioning generally includes two parts: wafer center positioning and product angle positioning. Product center positioning usually uses wafer edge information to locate the product center, while the product angle is usually determined by the Notch angle of the wafer edge. However, in the prior art, in the process of wafer positioning by obtaining wafer edge information and the Notch angle of the wafer, the obtained wafer edge information is often inaccurate or incomplete, which leads to poor wafer positioning accuracy. Summary of the invention

[0004] Based on this, it is necessary to provide a wafer alignment method and device that can improve the alignment accuracy of the wafer placed on the alignment platform in order to solve the above technical problems.

[0005] In a first aspect, the present application provides a wafer positioning method, the method comprising:

[0006] Moving the motion stage to the teaching position, and recording the calibration position coordinates and the calibration rotation angle when the motion stage is at the teaching position;

[0007] The image acquisition device is used to acquire images of characteristic marks of the calibration plate placed on the moving stage and images of the calibration plate at different rotation axis angles, so as to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system, wherein the images of the calibration plate at different rotation axis angles are acquired by driving the calibration plate to rotate at the calibration rotation angle amplitude driven by the moving stage;

[0008] The image acquisition device is used to acquire images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, wherein the images of the edge of the product to be positioned at different rotation axis angles are acquired by driving the moving stage to rotate the product to be positioned at the calibrated rotation angle amplitude;

[0009] According to the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, the position coordinates of the edge in the corresponding world coordinate system are obtained;

[0010] Based on the acquired position coordinates of the edge, acquiring the center position coordinates of the product to be positioned;

[0011] The image acquisition device is used to acquire contour information of the positioning mark on the product to be positioned, and the position coordinates of the positioning mark are acquired based on the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system.

[0012] In one embodiment, the image acquisition device is used to acquire images of characteristic marks of the calibration plate placed on the moving stage and images of the calibration plate at different rotation axis angles to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system, which includes:

[0013] By acquiring the position information of the feature mark and based on the pixel coordinates of the image acquisition device, the intrinsic parameter matrix of the image acquisition device is calibrated;

[0014] The characteristic marks at different positions on the calibration plate and images of the calibration plate at different rotation axis angles are collected by the image acquisition device to obtain a first external parameter matrix of the image acquisition device at different rotation axis angles;

[0015] Acquire the position coordinates of the rotation center of the motion stage based on the first extrinsic parameter matrix;

[0016] Based on the position coordinates of the rotation center, the intrinsic parameter matrix and the first extrinsic parameter matrix, a second extrinsic parameter matrix of the image acquisition device at any rotation axis angle is calculated to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system.

[0017] In one embodiment, the step of obtaining the position information of the feature mark and calibrating the intrinsic parameter matrix of the image acquisition device based on the pixel coordinates of the image acquisition device includes:

[0018] Calculating a center offset of the image acquisition device according to a sensor pixel size of the image acquisition device and a focal length of the image acquisition device;

[0019] Calculating the image pixel size according to the pixel spacing and physical distance between the two characteristic marks on the calibration plate in the field of view of the image acquisition device;

[0020] The image acquisition device internal parameters are calculated according to the image pixel size, and the internal parameter matrix of the image acquisition device is calibrated based on the center offset of the image acquisition device and the image acquisition device internal parameters.

[0021] In one embodiment, the capturing of the characteristic marks at different positions of the calibration plate and images of the calibration plate at different rotation axis angles by the image capture device to obtain a first external parameter matrix of the image capture device at different rotation axis angles includes:

[0022] Collecting images of multiple different positions on the calibration plate, and collecting images of the calibration plate at different rotation axis angles;

[0023] Based on the collected images of multiple different positions on the calibration plate, a pixel coordinate group of the feature mark and a corresponding coordinate group of the calibration plate are obtained;

[0024] Calculating the external parameters of the pixel coordinate group and the coordinate group of the calibration plate at the calibration rotation angle by the least square method;

[0025] The first extrinsic parameter matrix is ​​calculated based on the collected images of the calibration plate at different rotation axis angles and the obtained extrinsic parameters of the pixel coordinate group and the coordinate group of the calibration plate at the calibration rotation angle.

[0026] In one embodiment, acquiring the position coordinates of the rotation center of the motion stage based on the first extrinsic parameter matrix includes:

[0027] Based on the first extrinsic parameter matrix, calculating the coordinates of the calibration plate at the center of the image acquisition device at different rotation axis angles;

[0028] Based on the acquired coordinates of the calibration plate at the center of the multiple image acquisition devices, the position coordinates of the rotation center of the motion stage are obtained by least square fitting.

[0029] In one embodiment, the second external parameter matrix of the image acquisition device at any rotation axis angle is calculated based on the position coordinates of the rotation center, the internal parameter matrix and the first external parameter matrix to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system, and the calculation method includes:

[0030] ,

[0031] in Indicates that the rotation axis is at any angle The second external parameter matrix is, represents the position coordinates of the rotation center of the motion stage, Indicates that it is at the specified rotation angle The first external parameter matrix below.

[0032] In one embodiment, the step of acquiring images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles by the image acquisition device also includes:

[0033] An image enhancement device is used to sharpen the edge of the product to be positioned to enhance the image quality of the edge of the product to be positioned.

[0034] In one embodiment, the step of acquiring the center position coordinates of the product to be positioned based on the acquired position coordinates of the edge also includes:

[0035] A random sampling consistency algorithm is used to improve the accuracy of the obtained center position coordinates of the product to be located.

[0036] In a second aspect, the present application further provides a wafer positioning device, the device comprising:

[0037] A calibration plate, wherein a characteristic mark is provided on the calibration plate;

[0038] A moving platform, the moving platform is used to carry the calibration plate and the product to be positioned and drive the calibration plate and the product to be positioned to move and rotate;

[0039] An image acquisition device is used to acquire images of the characteristic marks of the calibration plate placed on the moving stage, images of the calibration plate at different rotation axis angles, images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, and contour information of the positioning marks on the product to be positioned, and the image acquisition device calibrates the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates through the calibration plate;

[0040] An information processing device, used for recording the calibrated position coordinates and the calibrated rotation angle of the motion stage at the teaching position, and for obtaining a mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, obtaining the position coordinates of the edge in the corresponding world coordinate system based on the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates, obtaining the center position coordinates of the product to be positioned based on the acquired position coordinates of the edge in the world coordinate system, and obtaining the position coordinates of the positioning mark based on the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates;

[0041] A mobile control device is used to control the motion platform to be in the teaching position and control the motion platform to rotate within the calibrated rotation angle range.

[0042] In one of the embodiments, the wafer positioning device also includes an image enhancement device, which is used to sharpen the edge of the product to be positioned when the image acquisition device acquires the image of the edge of the product to be positioned on the moving stage in the teaching position at different rotation axis angles, thereby enhancing the image quality of the edge of the product to be positioned.

[0043] The above-mentioned wafer positioning method and device, by setting up a calibration plate, and the calibration plate is provided with characteristic marks, and the image information located at different rotation axis angles obtained when the characteristic marks and the calibration plate are rotated at the calibration angle amplitude is collected to obtain the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates, so as to establish an accurate and comprehensive positioning model for the subsequent positioning of the product to be positioned; by collecting the edge image information located at different rotation axis angles obtained by rotating the product to be positioned at the same rotation angle amplitude in the field of view of the image acquisition device, and based on the model of the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates obtained based on the calibration plate, the center position coordinates of the product to be positioned are obtained, and by collecting the image of the contour information of the positioning mark of the product to be positioned in the field of view of a single image acquisition device, the position information of the positioning mark of the product to be positioned is obtained, and the positioning of the product to be positioned is completed by positioning the center position and the positioning mark of the product to be positioned, the positioning accuracy is high, the product yield is improved, and the impact on the subsequent process is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 is a schematic flow chart of a wafer positioning method in one embodiment;

[0046] Figure 2 is a schematic structural diagram of a wafer positioning device in one embodiment;

[0047] Figure 3 An optical image of a product to be positioned collected by an image enhancement device in one embodiment;

[0048] Figure 4 The optical image of another product to be positioned is collected by using an image enhancement device in one embodiment.

[0049] Description of reference numerals:

[0050] 1-moving stage, 2-image acquisition device, 21-positioning camera, 22-lens, 23-illumination part, 24-fixing part, 3-product to be positioned, 4-image enhancement device. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0052] In an exemplary embodiment, Figure 1 As shown, a wafer alignment method is provided, comprising the following steps.

[0053] Step S1: Move and rotate the motion stage 1 to the teaching position, and record the calibrated position coordinates and calibrated rotation angle of the motion stage 1 at the teaching position;

[0054] Step S2: The image acquisition device 2 acquires images of characteristic marks of the calibration plate placed on the moving stage 1 and images of the calibration plate at different rotation axis angles, so as to obtain a mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, wherein the images of the calibration plate at different rotation axis angles are acquired by driving the calibration plate to rotate at a calibration rotation angle amplitude driven by the moving stage 1;

[0055] S3: The image acquisition device 2 is used to acquire images of the edge of the product to be positioned 3 at different rotation axis angles on the moving stage 1 at the teaching position, wherein the images of the edge of the product to be positioned 3 at different rotation axis angles are acquired by driving the moving stage 1 to rotate the product to be positioned 3 at a calibrated rotation angle amplitude;

[0056] S4: according to the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, obtaining the position coordinates of the edge in the corresponding world coordinate system;

[0057] S5: based on the acquired edge position coordinates, acquiring the center position coordinates of the product 3 to be positioned;

[0058] S6: The contour information of the positioning mark on the product to be positioned 3 is collected by the image acquisition device 2, and the position coordinates of the positioning mark are obtained according to the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system.

[0059] Among them, the teaching position in step S1 refers to the position within the field of view of the image acquisition device 2 where the image information of the calibration plate and the product to be positioned 3 can be acquired, and when the product to be positioned 3 is positioned subsequently, the moving stage 1 must move to this position, which is the reference position for positioning; the positioning mark in step S6 refers to a specific groove on the edge of the product to be positioned 3, which is a physical incision used to identify the crystal orientation of the product to be positioned 3, which helps to accurately position and align the product to be positioned 3 during the process, usually in a V-shape or a U-shape, located at the bottom of the edge of the product to be positioned 3, such as Figure 3 to Figure 4 As shown, this positioning mark is more common in 8-inch and 12-inch wafers.

[0060] In the above wafer positioning method, a designed calibration plate is used, and the image acquisition device 2 is used to acquire image information at different rotation axis angles obtained when the feature mark and the calibration plate are rotated at the calibration angle amplitude, so as to obtain the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, and establish an accurate and comprehensive positioning model for the subsequent positioning of the product to be positioned; by acquiring edge image information at different rotation axis angles obtained by rotating the product 3 to be positioned at the same rotation angle amplitude in the field of view of the image acquisition device 2, and based on the model of the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system obtained based on the calibration plate, the center position coordinates of the product 3 to be positioned are obtained, and by acquiring the image of the contour information of the positioning mark of the product 3 to be positioned in the field of view of a single image acquisition device, the position information of the positioning mark of the product 3 to be positioned is obtained, so as to complete the positioning of the product 3 to be positioned, and the positioning accuracy is high, which ensures the smooth progress of the subsequent processes.

[0061] In an exemplary embodiment, an image acquisition device is used to acquire images of characteristic marks of a calibration plate placed on a moving stage and images of the calibration plate at different rotation axis angles to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system, including:

[0062] Step S21: calibrating the intrinsic parameter matrix of the image acquisition device 2 by acquiring the position information of the feature mark and based on the pixel coordinates of the image acquisition device 2;

[0063] Step S22: The image acquisition device 2 is used to acquire characteristic marks at different positions on the calibration plate and images of the calibration plate at different rotation axis angles, so as to obtain a first external parameter matrix of the image acquisition device 2 at different rotation axis angles;

[0064] Step S23: acquiring the position coordinates of the rotation center of the motion stage 1 based on the first external parameter matrix;

[0065] Step S24: Based on the position coordinates of the rotation center, the intrinsic parameter matrix and the first extrinsic parameter matrix, a second extrinsic parameter matrix of the image acquisition device 2 at any rotation axis angle is calculated to obtain a mapping relationship between the pixel coordinate system of the image acquisition device 2 and the world coordinate system.

[0066] In an exemplary embodiment, by acquiring the position information of the feature mark and based on the pixel coordinates of the image acquisition device 2, the intrinsic parameter matrix of the image acquisition device 2 is calibrated, including:

[0067] S211: Calculating the center offset of the image acquisition device 2 according to the pixel size of the image acquisition device 2 sensor and the focal length of the image acquisition device 2;

[0068] S212: Calculate the image pixel size according to the pixel spacing and physical distance between two characteristic marks on the calibration plate in the field of view of the image acquisition device 2;

[0069] S213: Calculate the internal parameters of the image acquisition device 2 according to the image pixel size, and calibrate the internal parameter matrix of the image acquisition device 2 based on the center offset of the image acquisition device 2 and the internal parameters of the image acquisition device 2.

[0070] Among them, the pixel size of the sensor of the image acquisition device 2 is , the focal length of the image acquisition device 2 is , the center offset of the image acquisition device 2 is and ,but , , the pixel spacing between two feature markers is , the physical distance is , the image pixel size is and , the internal parameter of image acquisition device 2 is and ,but , , , , then the internal parameter matrix .

[0071] In an exemplary embodiment, the image acquisition device 2 is used to acquire characteristic marks at different positions on the calibration plate and images of the calibration plate at different rotation axis angles to obtain a first external parameter matrix of the image acquisition device at different rotation axis angles, including:

[0072] S221: collecting images of multiple different positions on the calibration plate, and collecting images of the calibration plate at different rotation axis angles;

[0073] S222: based on the collected images of multiple different positions on the calibration plate, obtaining a pixel coordinate group of the feature mark and a corresponding coordinate group of the calibration plate;

[0074] S223: Calculate the external parameters of the pixel coordinate group and the coordinate group obtained by the calibration plate at a specific rotation angle by using the least square method;

[0075] S224: Calculate a first extrinsic parameter matrix based on the acquired images of the calibration plate at different rotation axis angles and the extrinsic parameters of the pixel coordinate group and the coordinate group of the calibration plate at the obtained calibration rotation angle.

[0076] According to the above steps S221 to S224, the calculation process of the first external parameter matrix is ​​as follows: the pixel coordinate group of the feature mark is identified on the images of the calibration plates at different positions collected The coordinate group corresponding to the calibration plate , the pixel coordinate group of the feature marker and the coordinate group of the calibration plate form a transformation matrix: , the least square method is used to solve the above equation to obtain the external parameter matrix of the image coordinates of the image acquisition device 2 and the coordinate system of the calibration plate at a specific angle (i.e., the calibration rotation angle): Based on the coordinate positions of the calibration plate at different rotation axis angles collected by rotating the motion stage at the calibration rotation angle, the external parameter matrix at different rotation axis angles can be calculated. , which is the first external parameter matrix.

[0077] In an exemplary embodiment, obtaining the position coordinates of the rotation center of the motion stage 1 based on the first external parameter matrix includes:

[0078] S231: Calculating the coordinates of the calibration plate at the center of the image acquisition device 2 at different rotation axis angles based on the first extrinsic matrix;

[0079] S232: Based on the acquired coordinates of the calibration plate at the center of the multiple image acquisition devices 2, the position coordinates of the rotation center of the motion stage 1 are obtained by using the least squares fitting method.

[0080] Among them, the number of image acquisition devices 2 is one and no rotation occurs, then the first external parameter matrix is ​​used Calculate the coordinates of the calibration plate at the center of the image acquisition device at different rotation axis angles In addition, if the image acquisition device does not rotate, the calibration plate coordinates based on the centers of the multiple image acquisition devices collected are Located on the same rotation arc, the least squares method can be used to obtain the rotation center of the motion stage .

[0081] In an exemplary embodiment, based on the position coordinates of the rotation center of the motion stage 1, the intrinsic parameter matrix and the first extrinsic parameter matrix, the second extrinsic parameter matrix of the image acquisition device 2 at any rotation axis angle is calculated, that is, the mapping relationship between the pixel coordinate system of the image acquisition device at any rotation axis angle and the world coordinate system is obtained, and the calculation method includes:

[0082] ,in Indicates that the rotation axis is at any angle The second external parameter matrix under represents the position coordinates of the rotation center of the motion stage 1, Indicates that it is at the calibration rotation angle The first external parameter matrix under, and based on the above steps S21 to S23, the rotation center of the motion stage 1 , at the calibration angle The first external parameter matrix under is known.

[0083] Exemplarily, when the product 3 to be positioned is placed on the moving stage 1, the moving stage 1 is in a standard unloading state, the moving stage 1 is in a teaching position, and a specific mark on the moving stage 1 is in a standard unloading position, which ensures the accuracy of the image information of the product to be positioned subsequently obtained. In other words, each time the product 3 to be positioned is positioned, the moving stage 1 needs to be adjusted to the teaching position. The product to be positioned includes a wafer.

[0084] In an exemplary embodiment, the image acquisition device 2 acquires images of the edge of the product to be positioned 3 on the moving stage at the teaching position at different rotation axis angles, and also includes:

[0085] Step S31: using the image enhancement device 4 to sharpen the edge of the product to be positioned, so as to enhance the image quality of the edge of the product to be positioned 3.

[0086] In an exemplary embodiment, based on the edge information in the acquired world coordinate system, obtaining the position coordinates of the center of the product 3 to be located also includes:

[0087] Step S41: Use a random sampling consensus algorithm to improve the accuracy of the center position coordinates of the product 3 to be located. The RANSAC (Random Sample Consensus) algorithm is an iterative method for data fitting and a random sampling algorithm for estimating the parameters of a mathematical model from data containing outliers. It can find the best model by repeatedly randomly selecting a subset of data and evaluate the consistency of the model in the entire data set. It has strong robustness to outliers and can effectively extract effective information from data containing a lot of noise. Therefore, when the position coordinates of the center of the product 3 to be located can be calculated by circle fitting based on the edge image of the product 3 to be located in the world coordinate system, the further use of the random sampling consensus algorithm can further improve the robustness of the circle fitting and ensure the accuracy of the fitting.

[0088] Exemplarily, the positioning mark is moved into the field of view of the image acquisition device 2. According to the mapping relationship between the pixel coordinate system of the image acquisition device 2 and the world coordinate system, the position information of the positioning mark can be calibrated based on the contour information of the positioning mark. It will not be repeated here. On this basis, by combining the center position coordinates of the product 3 to be positioned and the position information of the positioning mark, the positioning of the product 3 to be positioned can be completed, and the positioning accuracy is high, which ensures the smooth progress of subsequent processes.

[0089] 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.

[0090] Based on the same inventive concept, the embodiment of the present application also provides a wafer positioning device for implementing the wafer positioning method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more wafer positioning device embodiments provided below can refer to the limitations of the wafer positioning method above, and will not be repeated here.

[0091] In an exemplary embodiment, Figure 2As shown, a wafer positioning device is provided, comprising: a calibration plate, a moving stage 1, an image acquisition device 2, an information processing device and a mobile control device, wherein:

[0092] A calibration plate, provided with marking characteristic information;

[0093] The moving stage 1 is used to carry the calibration plate and the product to be positioned 3, and drive the calibration plate and the product to be positioned 3 to move and rotate;

[0094] The image acquisition device 2 is used to acquire images of characteristic marks of the calibration plate placed on the moving stage 1, images of the calibration plate at different rotation axis angles, images of the edge of the product to be positioned on the moving stage 1 at different rotation axis angles, and contour information of the positioning marks on the product to be positioned, and the image acquisition device 2 calibrates the mapping relationship between the pixel coordinates of the image acquisition device 2 and the world coordinates through the calibration plate;

[0095] An information processing device, used to obtain a mapping relationship between pixel coordinates of the image acquisition device 2 and world coordinates, obtain pixel coordinates of edge information, obtain objective coordinates of edge information in a corresponding world coordinate system based on the mapping relationship between pixel coordinates of the image acquisition device 2 and world coordinates, obtain center position coordinates of the product to be positioned based on the objective coordinates of edge information in the world coordinate system obtained, and calibrate position information of the positioning mark based on the mapping relationship between the pixel coordinate system of the image acquisition device 2 and the world coordinate system;

[0096] The mobile control device is used to control the motion platform 1 to be in the teaching position and control the motion platform 1 to rotate within a calibrated rotation angle range.

[0097] In an exemplary embodiment, Figure 3 and Figure 4 As shown, the wafer positioning device also includes an image enhancement device 4, which is used to sharpen the edge of the product to be positioned 3 when the image acquisition device 2 acquires images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, thereby enhancing the image quality of the edge of the product to be positioned 3. The image enhancement device 4 includes a backlight source.

[0098] Exemplarily, the image acquisition device 2 includes a positioning camera 21, a lens 22, a lighting unit 23 and a fixing unit 24. The lens 22 is used to acquire images of the calibration plate and the product 3 to be positioned. The positioning camera 21 is used to pre-process the images of the calibration plate and the product 3 to be positioned acquired by the lens 22. The lighting unit 23 is used to illuminate the process of the lens 22 acquiring the images of the calibration plate and the product 3 to be positioned so as to enhance the clarity of the acquired images of the calibration plate and the product 3 to be positioned. The fixing unit 24 is used to fix the positioning camera 21 and the lens 22.

[0099] The information acquisition device in the above-mentioned wafer positioning device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned information acquisition device can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0100] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0101] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A wafer positioning method, characterized in that: The method comprises: Moving the motion stage to the teaching position, and recording the calibration position coordinates and the calibration rotation angle when the motion stage is at the teaching position; The image acquisition device is used to acquire images of characteristic marks of the calibration plate placed on the moving stage and images of the calibration plate at different rotation axis angles, so as to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system, wherein the images of the calibration plate at different rotation axis angles are acquired by driving the calibration plate to rotate at a calibration rotation angle amplitude by the moving stage; The image acquisition device is used to acquire images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, wherein the images of the edge of the product to be positioned at different rotation axis angles are acquired by driving the moving stage to rotate the product to be positioned at a calibrated rotation angle amplitude; According to the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, the position coordinates of the edge in the corresponding world coordinate system are obtained; Based on the acquired position coordinates of the edge, acquiring the center position coordinates of the product to be positioned; The image acquisition device is used to acquire contour information of the positioning mark on the product to be positioned, and the position coordinates of the positioning mark are acquired based on the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system.

2. The method according to claim 1, characterized in that The step of acquiring the image of the characteristic mark of the calibration plate placed on the moving stage and the image of the calibration plate at different rotation axis angles by the image acquisition device to obtain the mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system includes: By acquiring the position information of the feature mark and based on the pixel coordinates of the image acquisition device, the intrinsic parameter matrix of the image acquisition device is calibrated; The characteristic marks at different positions on the calibration plate and images of the calibration plate at different rotation axis angles are collected by the image acquisition device to obtain a first external parameter matrix of the image acquisition device at different rotation axis angles; Acquire the position coordinates of the rotation center of the motion stage based on the first extrinsic parameter matrix; Based on the position coordinates of the rotation center, the intrinsic parameter matrix and the first extrinsic parameter matrix, a second extrinsic parameter matrix of the image acquisition device at any rotation axis angle is calculated to obtain a mapping relationship between a pixel coordinate system of the image acquisition device and a world coordinate system.

3. The method according to claim 2, characterized in that The step of acquiring the position information of the feature mark and calibrating the intrinsic parameter matrix of the image acquisition device based on the pixel coordinates of the image acquisition device includes: Calculating a center offset of the image acquisition device according to a sensor pixel size of the image acquisition device and a focal length of the image acquisition device; Calculating the image pixel size according to the pixel spacing and physical distance between the two characteristic marks on the calibration plate in the field of view of the image acquisition device; The intrinsic parameters of the image acquisition device are calculated according to the pixel size of the image, and the intrinsic parameter matrix of the image acquisition device is calibrated based on the center offset of the image acquisition device and the intrinsic parameters of the image acquisition device.

4. The method according to claim 2, characterized in that: The step of acquiring the characteristic marks at different positions on the calibration plate and the images of the calibration plate at different rotation axis angles by the image acquisition device to obtain the first external parameter matrix of the image acquisition device at different rotation axis angles includes: Collecting images of multiple different positions on the calibration plate, and collecting images of the calibration plate at different rotation axis angles; Based on the collected images of multiple different positions on the calibration plate, a pixel coordinate group of the feature mark and a corresponding coordinate group of the calibration plate are obtained; Calculating the external parameters of the pixel coordinate group and the coordinate group of the calibration plate at the calibration rotation angle by the least square method; The first extrinsic parameter matrix is ​​calculated based on the collected images of the calibration plate at different rotation axis angles and the obtained extrinsic parameters of the pixel coordinate group and the coordinate group of the calibration plate at the calibration rotation angle.

5. The method according to claim 2, characterized in that: The acquiring the position coordinates of the rotation center of the motion stage based on the first external parameter matrix comprises: Based on the first extrinsic parameter matrix, calculating the coordinates of the calibration plate at the center of the image acquisition device at different rotation axis angles; Based on the acquired coordinates of the calibration plate at the center of the multiple image acquisition devices, the position coordinates of the rotation center of the motion stage are obtained by least square fitting.

6. The method according to claim 2, characterized in that The second external parameter matrix of the image acquisition device at any rotation axis angle is calculated based on the position coordinates of the rotation center, the internal parameter matrix and the first external parameter matrix to obtain a mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, and the calculation method includes: ， in Indicates that the axis is at any rotation angle The second external parameter matrix is, represents the position coordinates of the rotation center of the motion stage, Indicates that it is at the specified rotation angle The first external parameter matrix below.

7. The method according to claim 1, characterized in that The image acquisition device is used to acquire images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, and also includes: An image enhancement device is used to sharpen the edge of the product to be positioned to enhance the image quality of the edge of the product to be positioned.

8. The method according to claim 1, characterized in that: The step of acquiring the center position coordinates of the product to be positioned based on the acquired position coordinates of the edge also includes: A random sampling consistency algorithm is used to improve the accuracy of the obtained center position coordinates of the product to be located.

9. A wafer positioning device, characterized in that: The device comprises: A calibration plate, wherein a characteristic mark is provided on the calibration plate; A moving platform, the moving platform is used to carry the calibration plate and the product to be positioned and drive the calibration plate and the product to be positioned to move and rotate; An image acquisition device is used to acquire images of the characteristic marks of the calibration plate placed on the moving stage, images of the calibration plate at different rotation axis angles, images of the edge of the product to be positioned on the moving stage at the teaching position at different rotation axis angles, and contour information of the positioning marks on the product to be positioned, and the image acquisition device calibrates the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates through the calibration plate; An information processing device, used for recording the calibrated position coordinates and the calibrated rotation angle of the motion stage at the teaching position, and for obtaining a mapping relationship between the pixel coordinate system of the image acquisition device and the world coordinate system, obtaining the position coordinates of the edge in the corresponding world coordinate system based on the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates, obtaining the center position coordinates of the product to be positioned based on the acquired position coordinates of the edge in the world coordinate system, and obtaining the position coordinates of the positioning mark based on the mapping relationship between the pixel coordinates of the image acquisition device and the world coordinates; A mobile control device is used to control the motion platform to be in the teaching position and control the motion platform to rotate within the calibrated rotation angle range.

10. The device according to claim 9, characterized in that The wafer positioning device also includes an image enhancement device, which is used to sharpen the edge of the product to be positioned when the image acquisition device acquires the image of the edge of the product to be positioned on the moving stage in the teaching position at different rotation axis angles, thereby enhancing the image quality of the edge of the product to be positioned.

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