Wafer pre-alignment system and method and storage medium

Abstract

The invention provides a wafer pre-alignment system and method and a storage medium, and the method comprises the steps: S101, obtaining the first wafer detection information of a wafer through a visual detection device when the wafer is fixed on a main suction cup; s102, acquiring a first wafer adjustment strategy according to the first wafer detection information; s103, controlling the pre-alignment device to execute a first wafer adjustment strategy; s104, second wafer detection information of the wafer is obtained through the visual detection device, and whether the wafer meets the wafer circle center positioning requirement or not is judged according to the second wafer detection information; s105, taking the second wafer detection information as new first wafer detection information and returning to the step S102 when the wafer circle center positioning requirement is not met; and when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle through a main rotating motor of the pre-alignment device. Through continuous detection and adjustment, it is ensured that the circle center of the wafer is consistent with the preset position, and the wafer positioning precision is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a wafer pre-alignment system, method and storage medium. Background Art

[0002] In the existing wafer alignment process, the positioning of the wafer notch is used as a pre-alignment task. It mainly collects edge data during the wafer rotation process through sensors, obtains the approximate orientation of the notch based on the edge data, and uses the approximate orientation corresponding to the notch as a reference point to rotate the wafer so that the notch rotates to a preset direction to achieve wafer pre-alignment. However, if the wafer deviates from the rotation center of the rotating motor before rotation, the wafer positioning accuracy will be unsatisfactory.

[0003] Based on this, the present application provides a wafer pre-alignment system, method and storage medium to improve the existing technology and meet the needs of practical applications. Summary of the invention

[0004] The purpose of the present application is to provide a wafer pre-alignment system, method and storage medium, which solves the problem that if the wafer deviates from the rotation center of the rotating motor before rotation, the wafer positioning accuracy will be unsatisfactory.

[0005] The purpose of this application is achieved by the following technical solutions:

[0006] In a first aspect, the present application provides a wafer pre-alignment system, comprising:

[0007] A visual inspection device for collecting edge data of the wafer as it rotates;

[0008] The pre-alignment device includes a main suction cup, a main linear motor and a main rotary motor, which is used to fix and drive the wafer to rotate through the main suction cup, and move the center of the rotated wafer to a preset center position through the main linear motor;

[0009] The invention also includes a controller, the controller is electrically connected to the visual inspection device and the pre-alignment device, and the controller is configured to:

[0010] S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch;

[0011] S102, acquiring a first wafer adjustment strategy according to the first wafer detection information;

[0012] S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer;

[0013] S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information;

[0014] S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning;

[0015] Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

[0016] In some possible implementations, the pre-alignment device includes a first vacuum suction cup, a second vacuum suction cup, a first linear motor, a first rotary motor, and a first lifting module, wherein the first vacuum suction cup is used as a main suction cup, the first rotary motor is used as a main rotary motor, and the first linear motor is used as a main linear motor; the first rotary motor is connected to the first vacuum suction cup, and when the first rotary motor is started, the wafer is driven to rotate through the first vacuum suction cup; the first lifting module is connected to the first rotary motor or the first vacuum suction cup, and when the first lifting module rises or falls, the height difference between the first vacuum suction cup and the second vacuum suction cup is changed;

[0017] The first wafer adjustment strategy includes:

[0018] Using the first rotary motor to drive the first vacuum chuck to rotate, so as to adjust the eccentric angle of the wafer, so that the connecting line of the wafer motor axis is parallel to the moving direction of the first linear motor;

[0019] Using the first lifting module to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, when the two are on the same horizontal plane, control the second vacuum suction cup to fix the wafer, and then continue to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup to a preset height difference;

[0020] The wafer is driven by the first linear motor to move toward or away from the first rotary motor, so that the center of the wafer approaches a preset center position;

[0021] The first lifting module is used to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, and when the two are in the same plane, the first vacuum suction cup is controlled to fix the wafer, and then the height difference between the first vacuum suction cup and the second vacuum suction cup is restored to a preset height difference.

[0022] In some possible implementations, the pre-alignment device includes a third vacuum suction cup, a second linear motor, a second rotary motor and a third rotary motor, wherein the third vacuum suction cup is used as a main suction cup, the third rotary motor is used as a main rotary motor, and the second linear motor is used as a main linear motor; the second rotary motor is connected to the third vacuum suction cup so that the wafer is driven to rotate when the third vacuum suction cup fixes the wafer; the third rotary motor is arranged in a direction away from the third vacuum suction cup, and the wafer is driven to rotate through the second rotary motor and the third vacuum suction cup when the third rotary motor is started; the second linear motor is arranged between the second rotary motor and the third rotary motor, and is used to drive the rotation axis of the second rotary motor to approach or move away from the rotation axis of the third rotary motor;

[0023] The first wafer adjustment strategy includes:

[0024] The third vacuum chuck is driven to rotate by the second rotary motor to adjust the eccentric angle of the wafer so that the connecting line of the wafer motor axis is parallel to the moving direction of the second linear motor;

[0025] The second linear motor drives the rotation axis of the second rotary motor to move toward or away from the rotation axis of the third rotary motor, so that the center of the wafer approaches a preset center position.

[0026] In some possible implementations, the controller is further configured to obtain the first wafer detection information of the wafer in the following manner:

[0027] Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup;

[0028] Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device;

[0029] Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

[0030] In some possible implementations, the controller is further configured to obtain first wafer detection information of the wafer based on the template image information and the template image information in the following manner:

[0031] Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data;

[0032] A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer;

[0033] Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data;

[0034] The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

[0035] In some possible implementations, the controller is further configured to rotate the adjusted wafer to a specified angle through a main rotation motor of the pre-alignment device in the following manner:

[0036] The precise position of the notch of the wafer is located by using an image processing algorithm; and the wafer is rotated to a specified angle by a main rotating motor of the pre-alignment device according to the precise position of the notch of the wafer.

[0037] In a second aspect, the present application further provides a wafer pre-alignment method, the wafer pre-alignment method being applied to the wafer pre-alignment system according to any one of the first aspects, the wafer pre-alignment system comprising a visual inspection device and a pre-alignment device; the wafer pre-alignment method comprising:

[0038] S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch;

[0039] S102, acquiring a first wafer adjustment strategy according to the first wafer detection information;

[0040] S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer;

[0041] S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information;

[0042] S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning;

[0043] Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the line between the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

[0044] In some possible implementations, the acquiring the first wafer inspection information of the wafer by the visual inspection device includes:

[0045] Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup;

[0046] Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device;

[0047] Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

[0048] In some possible implementations, the acquiring first wafer detection information of the wafer based on the template image information and the template image information includes:

[0049] Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data;

[0050] A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer;

[0051] Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data;

[0052] The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

[0053] In a third aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the steps of the method described in the second aspect are implemented.

[0054] Compared with the prior art, the wafer pre-alignment system, method and storage medium provided by the present invention, according to the first wafer detection information collected, the controller calculates the adjustment strategy, the purpose is to perform preliminary centroid positioning on the wafer. Then the pre-alignment device is guided to execute the adjustment strategy through the main suction cup, the main linear motor and the main rotary motor to adjust the position and angle of the wafer. The second detection information of the wafer is obtained again through the visual inspection device, and compared with the historical data to evaluate whether the wafer meets the centroid positioning requirements. If the wafer does not meet the positioning requirements, the second detection information is used as the new first detection information, and the adjustment strategy is re-executed. When the wafer meets the positioning requirements, the main rotary motor rotates the wafer to the specified angle to complete the notch positioning (wafer alignment). Therefore, through continuous detection and adjustment, it is ensured that the center of the wafer is consistent with the preset position, thereby improving the accuracy of wafer positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The present application is further described below in conjunction with the accompanying drawings and implementation methods.

[0056] Figure 1 It is a structural block diagram of a wafer alignment system provided in an embodiment of the present application.

[0057] Figure 2 It is a structural schematic diagram of a wafer alignment system provided in an embodiment of the present application.

[0058] Figure 3 This is a front view of a wafer alignment system provided in an embodiment of the present application.

[0059] Figure 4 It is a structural schematic diagram of another wafer alignment system provided in an embodiment of the present application.

[0060] Figure 5 This is a partial wafer image acquired using a camera.

[0061] Figure 6 It is the template of the vertical direction and horizontal direction of the Sobel operator provided in the embodiment of the present application.

[0062] Figure 7 It is a schematic diagram of locating a notch position by notch feature points provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The technical solution in the present application will be described below in conjunction with the drawings and specific implementation methods of the specification of the present application. It should be noted that, under the premise of no conflict, the various implementation methods or technical features described below can be arbitrarily combined to form a new implementation method.

[0064] In the embodiments of the present application, the words "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any implementation or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other implementations or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0065] The technical solution in this application will be described below in conjunction with the drawings and specific implementation methods of the specification of this application. It should be noted that, under the premise of no conflict, the various implementation methods or technical features described below can be arbitrarily combined to form a new implementation method. The system will be described first, and then the method and storage medium will be described.

[0066] System Embodiments.

[0067] See also Figure 1 , Figure 1 It is a structural block diagram of a wafer alignment system provided in an embodiment of the present application.

[0068] The embodiment of the present application provides a wafer pre-alignment system, comprising:

[0069] A visual inspection device for collecting edge data of the wafer as it rotates;

[0070] A pre-alignment device, including a main suction cup, a main linear motor and a main rotary motor, is used to fix and drive the wafer to rotate through the main suction cup, and move the center of the rotated wafer to a preset center position through the main linear motor (to achieve centroid positioning of the wafer);

[0071] It also includes a controller, which is electrically connected to the visual inspection equipment and the pre-alignment device.

[0072] The controller is configured to:

[0073] S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch;

[0074] S102, acquiring a first wafer adjustment strategy according to the first wafer detection information;

[0075] S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer;

[0076] S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information;

[0077] S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning;

[0078] Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

[0079] Based on the first wafer detection information collected, the controller calculates the adjustment strategy, the purpose of which is to perform preliminary centroid positioning on the wafer. Then the pre-alignment device is guided to execute the adjustment strategy through the main suction cup, main linear motor and main rotary motor to adjust the position and angle of the wafer. The second detection information of the wafer is obtained again through the visual inspection device, and can be compared with historical data to evaluate whether the wafer meets the centroid positioning requirements. If the wafer does not meet the positioning requirements, the second detection information is used as the new first detection information, and the adjustment strategy is re-executed. When the wafer meets the positioning requirements, the main rotary motor is used to rotate the wafer to the specified angle to complete the notch positioning (wafer alignment).

[0080] The advantage of this embodiment is that, through continuous detection and adjustment, the center of the wafer is ensured to be consistent with the preset position, thereby improving the accuracy of wafer positioning.

[0081] In some embodiments, judging whether the wafer meets the wafer center positioning requirement according to the second wafer detection information includes:

[0082] Comparing the second wafer detection information with a plurality of historical wafer detection information, obtaining a historical wafer detection information with the highest similarity to the second wafer detection information as the target wafer detection information; the historical wafer detection information includes detection information of the same type of wafers that have been detected before and an evaluation of whether the wafer center positioning requirement is met; the evaluation is, for example, met, not met, qualified, or unqualified;

[0083] The evaluation of the target wafer detection information is used as an evaluation of whether the wafer meets the wafer center positioning requirement, and whether the wafer meets the wafer center positioning requirement is determined based on the evaluation.

[0084] The present application does not limit the method for obtaining the above similarity, for example: compare each parameter (such as eccentricity, eccentricity angle) in the second wafer detection information with the corresponding parameter in the historical data set (including multiple historical wafer detection information). Calculate the difference or distance between each historical wafer detection information and the current wafer detection information. Select the historical wafer detection information with the smallest difference as the target wafer detection information.

[0085] It can be considered that, based on the first wafer detection information, the process of obtaining the first wafer adjustment strategy is to compare the first wafer detection information with the wafer template information of the wafer (including the center coordinates of the main suction cup or the set of preset contour points when the wafer is fixed on the main suction cup), and the process of judging whether the wafer meets the wafer center positioning requirements is to compare the second wafer detection information with the historical wafer detection information. The first comparison is a comparison with an ideal state, which is a goal-oriented process for generating an adjustment strategy. The second comparison is a comparison with actual historical data, which is a result evaluation process for verifying the effectiveness of the adjustment strategy. By combining the above steps for different purposes, efficient and accurate wafer positioning can be achieved.

[0086] See also Figure 2 and Figure 3 , Figure 2 is a schematic structural diagram of a wafer alignment system provided in an embodiment of the present application, Figure 3 This is a front view of a wafer alignment system provided in an embodiment of the present application.

[0087] In some embodiments, the pre-alignment device includes a first vacuum suction cup, a second vacuum suction cup, a first linear motor, a first rotary motor and a first lifting module, wherein the first vacuum suction cup is used as a main suction cup, the first rotary motor is used as a main rotary motor, and the first linear motor is used as a main linear motor; the first rotary motor is connected to the first vacuum suction cup, and the wafer is driven to rotate through the first vacuum suction cup when the first rotary motor is started; the first lifting module is connected to the first rotary motor or the first vacuum suction cup, and the height difference between the first vacuum suction cup and the second vacuum suction cup is changed when the first lifting module rises or falls;

[0088] The first wafer adjustment strategy includes:

[0089] Using the first rotary motor to drive the first vacuum chuck to rotate, so as to adjust the eccentric angle of the wafer, so that the connecting line of the wafer motor axis is parallel to the moving direction of the first linear motor;

[0090] Using the first lifting module to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, when the two are on the same horizontal plane, control the second vacuum suction cup to fix the wafer, and then continue to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup to a preset height difference;

[0091] The wafer is driven by the first linear motor to move toward or away from the first rotary motor, so that the center of the wafer approaches a preset center position;

[0092] The first lifting module is used to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, and when the two are in the same plane, the first vacuum suction cup is controlled to fix the wafer, and then the height difference between the first vacuum suction cup and the second vacuum suction cup is restored to a preset height difference.

[0093] The pre-alignment device includes two vacuum suction cups (first and second vacuum suction cups) that work together to fix and support the wafer. The first rotary motor (main rotary motor) is connected to the first vacuum suction cup (main suction cup) and drives the wafer to rotate when started. The first rotary motor is used to adjust the rotation angle of the wafer so that the motor shaft connection line of the wafer is parallel to the movement direction of the first linear motor, so as to perform subsequent wafer alignment operations. The first lifting module is connected to the first rotary motor or the first vacuum suction cup, and changes the height difference between the first and second vacuum suction cups by rising or falling. When the two suction cups are in a horizontal plane, the second vacuum suction cup is controlled to fix the wafer, and then continue to adjust to the preset height difference. The first linear motor is used to drive the wafer to move so that the center of the wafer is close to the preset center position. The height difference is adjusted again using the first lifting module to ensure that the first vacuum suction cup fixes the wafer and then returns to the preset height difference.

[0094] The advantage of this embodiment is that the alignment accuracy and production efficiency in the wafer manufacturing process are significantly improved through multi-suction cup fixation, dynamic height difference adjustment and precise automatic control.

[0095] See also Figure 4 , Figure 4 It is a structural schematic diagram of another wafer alignment system provided in an embodiment of the present application.

[0096] In some embodiments, the pre-alignment device includes a third vacuum suction cup, a second linear motor, a second rotary motor and a third rotary motor, wherein the third vacuum suction cup is used as a main suction cup, the third rotary motor is used as a main rotary motor, and the second linear motor is used as a main linear motor; the second rotary motor is connected to the third vacuum suction cup so that the wafer is driven to rotate when the third vacuum suction cup fixes the wafer; the third rotary motor is arranged in a direction away from the third vacuum suction cup, and the wafer is driven to rotate through the second rotary motor and the third vacuum suction cup when the third rotary motor is started; the second linear motor is arranged between the second rotary motor and the third rotary motor, and is used to drive the rotation axis of the second rotary motor to approach or move away from the rotation axis of the third rotary motor;

[0097] The first wafer adjustment strategy includes:

[0098] The third vacuum chuck is driven to rotate by the second rotary motor to adjust the eccentric angle of the wafer so that the connecting line of the wafer motor axis is parallel to the moving direction of the second linear motor;

[0099] The second linear motor drives the rotation axis of the second rotary motor to move toward or away from the rotation axis of the third rotary motor, so that the center of the wafer approaches a preset center position.

[0100] The third vacuum suction cup is used as the main suction cup to fix the wafer; the third rotary motor is used as the main rotary motor to drive the wafer to rotate; the second linear motor and the second rotary motor are used together to adjust the position and angle of the wafer. The third vacuum suction cup is driven to rotate by the second rotary motor to adjust the eccentric angle of the wafer, ensuring that the connection line of the wafer motor axis is parallel to the movement direction of the second linear motor, which helps to accurately align the wafer. The second linear motor is used to drive the second rotary motor to make it close to or away from the rotation axis of the third rotary motor, thereby adjusting the position of the wafer. Through the movement of the second linear motor, the center of the wafer is brought close to the preset center position to achieve precise alignment of the wafer.

[0101] The advantage of this embodiment is that the alignment process is simplified through the coordinated work of the motors, making the operation easier and reducing the difficulty of operation.

[0102] In some embodiments, the controller is further configured to obtain first wafer detection information of the wafer in the following manner:

[0103] Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup;

[0104] Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device;

[0105] Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

[0106] The wafer template information may include the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup, which can be used as a reference for subsequent wafer detection and alignment. The edge data of the wafer is collected by a visual inspection device when it rotates, and the edge data is used to generate a grayscale image of the edge of the wafer. The grayscale image is a single-channel image that reflects the brightness changes at the edge of the wafer, which is helpful for subsequent image processing and analysis. The collected grayscale image is matched with the wafer template information, for example, through image processing technology (such as image registration, feature point detection, etc.), to determine the difference between the actual position of the wafer and the template. Based on the template image information and the collected grayscale image, the first wafer detection information of the wafer is calculated.

[0107] The advantage of this embodiment is that detailed detection information of the wafer is obtained, and high-precision data support is provided for subsequent alignment and adjustment, thereby reducing wafer waste due to positioning errors and reducing production costs.

[0108] In some embodiments, the controller is further configured to obtain first wafer detection information of the wafer based on the template image information and the template image information in the following manner:

[0109] Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data;

[0110] A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer;

[0111] Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data;

[0112] The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

[0113] It can be understood that the collected grayscale image is Gaussian blurred to remove noise in the image and improve the accuracy of subsequent processing. The Sobel operator can highlight the edge information in the image. The image after Gaussian blur is processed using the Sobel operator to calculate the gradient amplitude and gradient direction of each pixel in the image. Using the acquired gradient amplitude and gradient direction data, the wafer edge is subjected to non-maximum suppression operation, which helps to determine the exact position of the edge point and remove the pseudo edge in edge detection. After non-maximum suppression, the edge point set of the wafer is obtained, and the points in the edge point set are accurate representations of the wafer edge. The least squares method is a mathematical optimization technique that can find the center and radius of the best fitting circle. Based on the edge point set, the circle is fitted using the least squares method. The fitted center and radius data are compared and calculated with the preset wafer template information to obtain the first wafer detection information of the wafer, such as eccentricity, eccentricity angle, etc.

[0114] The benefit of this embodiment is that the application of Gaussian blur and Sobel operator effectively improves the detection accuracy of edges in the image and reduces noise interference. Non-maximum suppression ensures the precise positioning of edge points and provides an accurate data basis for subsequent circle fitting. The automated circle fitting process of the least squares method reduces manual operations and improves the accuracy of the center and radius data. All detection and alignment strategies are based on precise data collection and analysis, ensuring the scientificity and effectiveness of decision-making. In summary, through automated image acquisition, preprocessing, edge detection and circle fitting, the detection accuracy and efficiency in the wafer manufacturing process are significantly improved.

[0115] As an example, image processing and geometric calculations are relied upon to determine and correct for the eccentricity and eccentricity angle of the wafer.

[0116] First, use a camera (visual inspection device) to record the image of the wafer rotating one circle, see Figure 5 , Figure 5 It is a partial wafer image acquired by a camera. Then image denoising is performed. Specifically, denoising can remove some noise points in the image, so that edge detection is free from noise interference. Generally, the value of the center point of the denoising convolution kernel is determined by the mean of the pixels of the surrounding points. Taking the 8-neighborhood of the 3*3 convolution kernel as an example, the coordinate value of the convolution center point is determined by the mean of the surrounding coordinates and itself. However, this method of determining the center point by the mean is essentially that the surrounding points all use the same weight, but when the convolution kernel becomes larger, it is obviously inappropriate for the point farthest from the center point to have the same weight as the closest point. The Gaussian kernel can be further processed. Gaussian blur (Gaussian smoothing) is to use the two-dimensional Gaussian distribution formula to distribute the weights of points at different positions in the convolution kernel according to the Gaussian distribution (normal distribution).

[0117] Then edge detection is performed. First, the image gradient information (gradient magnitude and gradient direction) is obtained. The edge is determined based on the image gradient magnitude and gradient direction. The Sobel operator can be used to calculate the gradient magnitude and gradient direction of the image. The Sobel operator is divided into two templates: vertical and horizontal. See Figure 6 , Figure 6 It is the template of the vertical direction and horizontal direction of the Sobel operator provided in the embodiment of the present application. The calculation formula of the gradient amplitude G and the gradient direction θ is as follows:

[0118] ,

[0119] in:

[0120]

[0121]

[0122] in, and It can correspond to the gradient components in the horizontal and vertical directions respectively, and x and y can refer to the position coordinates of the pixel point. After obtaining the gradient amplitude and gradient direction of the image, the image edge is subjected to non-maximum suppression operation through the obtained gradient amplitude and gradient direction. Since the gradient direction is perpendicular to the edge direction, non-maximum suppression can effectively eliminate a large part of non-edge points. The edge points obtained by edge detection are used to obtain an edge point set. The obtained edge point set is used to fit a circle to obtain the center and radius, and then compared and calculated with the preset wafer template information to obtain the first wafer detection information of the wafer, such as eccentricity, eccentricity angle, etc.

[0123] In some embodiments, the controller is further configured to rotate the adjusted wafer to a specified angle through a main rotation motor of the pre-alignment device in the following manner:

[0124] The precise position of the notch of the wafer is located by using an image processing algorithm; and the wafer is rotated to a specified angle by a main rotating motor of the pre-alignment device according to the precise position of the notch of the wafer.

[0125] Use a visual inspection device (such as a camera) to capture an image of the wafer, and use an image processing algorithm to analyze the captured image to determine the exact location of the notch. Identify the feature points of the notch in the image, such as the center point of the notch or the geometric center of the notch. Based on the location of the notch feature point and the preset reference direction, calculate the angle that the wafer needs to rotate so that the notch is aligned with the specified angle. The controller drives the wafer to rotate to the specified angle through the main rotation motor of the pre-alignment device based on the calculated angle.

[0126] The advantage of this embodiment is that the notch position can be accurately located by using the image processing algorithm, ensuring that the wafer can be accurately oriented to the required angle. Accurate orientation helps ensure that the wafer maintains the correct direction during subsequent processing, thereby improving the quality of the final product.

[0127] As an example, in wafer alignment technology, a geometric calculation method is used to find the notch feature point using the feature with the shortest distance from the edge to the suction cup (p-chuck). Among them, the notch is a specific mark on the wafer, usually a semicircular groove, which is used for wafer orientation and identification. The notch feature point refers to the position of the notch center. The main suction cup is a device used to fix and support the wafer, and the center of the main suction cup can be regarded as the center of rotation of the wafer. The distance from any point on the edge of the wafer to the center of the main suction cup can reflect the position of the point relative to the preset center of the wafer. The notch feature point can be the point on the wafer closest to the center of the suction cup, that is, the straight-line distance from the center of the notch to the center of the suction cup is the shortest among all points on the edge of the wafer. By calculating the distance from all points on the edge of the wafer to the center of the suction cup and finding the point with the shortest distance, the position of the notch feature point can be determined, that is, the precise position of the notch is obtained. After finding the notch feature point, the notch feature point is used to orient the wafer. See. Figure 7 , Figure 7 This is a schematic diagram of locating the notch position by notch feature points provided by an embodiment of the present application. Then, the controller can command the rotary motor to rotate the notch to a specific position to facilitate further processing or measurement of the wafer. Because the inherent geometric features on the wafer are used for precise positioning, the reliance on external marks or complex algorithms is reduced, and the accuracy and efficiency of alignment are improved.

[0128] Method embodiment.

[0129] The embodiment of the present application provides a wafer pre-alignment method, which is used in the wafer pre-alignment system described in any one of the system embodiments, and its working principle and beneficial effects are the same or similar to those in the system embodiment, and will not be described in detail. The wafer pre-alignment method includes:

[0130] S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch;

[0131] S102, acquiring a first wafer adjustment strategy according to the first wafer detection information;

[0132] S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer;

[0133] S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information;

[0134] S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning;

[0135] Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the line between the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

[0136] In some embodiments, a method of obtaining first wafer detection information of the wafer includes:

[0137] Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup;

[0138] Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device;

[0139] Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

[0140] In some embodiments, based on the template image information and the template image information, a method of acquiring first wafer detection information of the wafer includes:

[0141] Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data;

[0142] A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer;

[0143] Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data;

[0144] The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

[0145] In some embodiments, rotating the adjusted wafer to a specified angle through a main rotating motor of a pre-alignment device includes:

[0146] The precise position of the notch of the wafer is located by using an image processing algorithm; and the wafer is rotated to a specified angle by a main rotating motor of the pre-alignment device according to the precise position of the notch of the wafer.

[0147] Computer readable storage medium embodiments.

[0148] The computer-readable storage medium stores program codes for execution by a device, and the program codes include steps for executing a method as described in any one of the method embodiments. The specific embodiments are consistent with the embodiments and technical effects recorded in the above method embodiments, and some contents are not repeated here.

[0149] The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the steps of any of the above methods are implemented.

[0150] Computer readable medium can be a computer readable signal medium or a computer readable storage medium. In the present application embodiment, computer readable storage medium can be any tangible medium containing or storing a program, and the program can be used by an instruction execution system, device or device or used in combination with it. Computer readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of computer readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0151] The computer-readable storage medium may include a data signal propagated in a baseband or as part of a carrier wave, wherein a readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable storage medium may also be any computer-readable medium that can send, propagate, or transmit a program for use by an instruction execution system, an apparatus, or a device or for use in combination with it. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above. The program code for performing the operation of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and also conventional procedural programming languages ​​such as C language or similar programming languages. The program code may be executed entirely on a user computing device, partially on a user device, as an independent software package, partially on a user computing device, partially on a remote computing device, or entirely on a remote computing device or server. Where a remote computing device is involved, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0152] It should be noted that in the embodiments of the present application, "at least one" refers to one or more, and "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can represent: a, b, c, a and b, a and c, b and c or a and b and c, where a, b and c can be single or multiple. It is worth noting that "at least one" can also be interpreted as "one or more items".

[0153] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are configured to distinguish similar objects, and are not necessarily configured to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0154] This application is explained from the perspectives of purpose of use, effectiveness, progress and novelty, and has met the functional enhancement and usage requirements emphasized by the Patent Law. The above description and drawings of this application are only the preferred embodiments of this application, and are not intended to limit this application. Therefore, all structures, devices, features, etc. that are similar or identical to this application, that is, all equivalent replacements or modifications made in accordance with the scope of the patent application of this application, should fall within the scope of protection of the patent application of this application.

Claims

1. A wafer pre-alignment system, characterized in that: include: A visual inspection device for collecting edge data of the wafer as it rotates; The pre-alignment device includes a main suction cup, a main linear motor and a main rotary motor, which is used to fix and drive the wafer to rotate through the main suction cup, and move the center of the rotated wafer to a preset center position through the main linear motor; The invention also includes a controller, the controller is electrically connected to the visual inspection device and the pre-alignment device, and the controller is configured to: S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch; S102, acquiring a first wafer adjustment strategy according to the first wafer detection information; S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer; S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information; S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning; Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the line between the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

2. The wafer pre-alignment system according to claim 1, characterized in that: The pre-alignment device comprises a first vacuum suction cup, a second vacuum suction cup, a first linear motor, a first rotary motor and a first lifting module, wherein the first vacuum suction cup is used as a main suction cup, the first rotary motor is used as a main rotary motor, and the first linear motor is used as a main linear motor; the first rotary motor is connected to the first vacuum suction cup, and when the first rotary motor is started, the wafer is driven to rotate through the first vacuum suction cup; The first lifting module is connected to the first rotating motor or the first vacuum suction cup, and changes the height difference between the first vacuum suction cup and the second vacuum suction cup when the first lifting module rises or falls; The first wafer adjustment strategy includes: Using the first rotary motor to drive the first vacuum chuck to rotate, so as to adjust the eccentric angle of the wafer, so that the connecting line of the wafer motor axis is parallel to the moving direction of the first linear motor; Using the first lifting module to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, when the two are on the same horizontal plane, control the second vacuum suction cup to fix the wafer, and then continue to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup to a preset height difference; The wafer is driven by the first linear motor to move toward or away from the first rotary motor, so that the center of the wafer approaches a preset center position; The first lifting module is used to adjust the height difference between the first vacuum suction cup and the second vacuum suction cup, and when the two are in the same plane, the first vacuum suction cup is controlled to fix the wafer, and then the height difference between the first vacuum suction cup and the second vacuum suction cup is restored to a preset height difference.

3. The wafer pre-alignment system according to claim 1, characterized in that: The pre-alignment device comprises a third vacuum suction cup, a second linear motor, a second rotary motor and a third rotary motor, wherein the third vacuum suction cup is used as a main suction cup, the third rotary motor is used as a main rotary motor, and the second linear motor is used as a main linear motor; the second rotary motor is connected to the third vacuum suction cup so that the wafer is driven to rotate when the third vacuum suction cup fixes the wafer; the third rotary motor is arranged in a direction away from the third vacuum suction cup, and the wafer is driven to rotate through the second rotary motor and the third vacuum suction cup when the third rotary motor is started; the second linear motor is arranged between the second rotary motor and the third rotary motor, and is used to drive the rotation axis of the second rotary motor to approach or move away from the rotation axis of the third rotary motor; The first wafer adjustment strategy includes: The third vacuum chuck is driven to rotate by the second rotary motor to adjust the eccentric angle of the wafer so that the connecting line of the wafer motor axis is parallel to the moving direction of the second linear motor; The second linear motor drives the rotation axis of the second rotary motor to move toward or away from the rotation axis of the third rotary motor, so that the center of the wafer approaches a preset center position.

4. The wafer pre-alignment system according to claim 2 or 3, characterized in that: The controller is further configured to obtain first wafer detection information of the wafer in the following manner: Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup; Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device; Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

5. The wafer pre-alignment system according to claim 4, characterized in that: The controller is further configured to obtain first wafer detection information of the wafer based on the template image information and the template image information in the following manner: Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data; A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer; Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data; The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

6. The wafer pre-alignment system according to claim 1, characterized in that: The controller is further configured to rotate the adjusted wafer to a specified angle through a main rotating motor of the pre-alignment device in the following manner: The precise position of the notch of the wafer is located by using an image processing algorithm; and the wafer is rotated to a specified angle by a main rotating motor of the pre-alignment device according to the precise position of the notch of the wafer.

7. A wafer pre-alignment method, characterized in that: The wafer pre-alignment method is applied to the wafer pre-alignment system according to any one of claims 1 to 6, wherein the wafer pre-alignment system comprises a visual inspection device and a pre-alignment device; the wafer pre-alignment method comprises: S101, when the wafer is fixed on the main suction cup, obtaining first wafer detection information of the wafer through the visual inspection device, the first wafer detection information including eccentricity data, eccentricity angle data and rough position of the notch; S102, acquiring a first wafer adjustment strategy according to the first wafer detection information; S103, controlling the pre-alignment device to execute the first wafer adjustment strategy to achieve centroid positioning of the wafer; S104, obtaining second wafer inspection information of the wafer through the visual inspection device, and judging whether the wafer meets the wafer center positioning requirement according to the second wafer inspection information; S105, when the wafer center positioning requirement is not met, the second wafer detection information is used as the new first wafer detection information and the process returns to S102; when the wafer center positioning requirement is met, the adjusted wafer is rotated to a specified angle by a main rotating motor of a pre-alignment device to complete the wafer notch positioning; Among them, the first wafer adjustment strategy includes: rotating the wafer to adjust the eccentric angle so that the wafer motor axis line is parallel to the movement direction of the main linear motor, and the wafer motor axis line refers to the line between the center of the wafer and the axis of the main rotary motor; then controlling the movement of the wafer so that the center of the wafer is close to the preset center position.

8. The wafer pre-alignment method according to claim 7, characterized in that: The step of obtaining first wafer inspection information of the wafer by using the visual inspection device includes: Acquire wafer template information of the wafer, wherein the wafer template information includes the center coordinates of the main suction cup or a set of preset contour points when the wafer is fixed on the main suction cup; Obtaining a grayscale image of the wafer edge using the edge data acquired by the visual inspection device; Based on the template image information and the template image information, first wafer detection information of the wafer is acquired.

9. The wafer pre-alignment method according to claim 8, characterized in that: The acquiring first wafer detection information of the wafer based on the template image information and the template image information includes: Performing Gaussian blur on the grayscale image to remove noise, and then using the Sobel operator to calculate the gradient magnitude and gradient direction to obtain gradient magnitude and gradient direction data; A non-maximum suppression operation is performed on the edge of the wafer by using the acquired gradient amplitude and gradient direction data to obtain a set of edge points of the wafer; Based on the edge point set, a least square method is used to fit a circle to obtain the center and radius data; The first wafer detection information of the wafer is obtained by calculating based on the obtained circle center and radius data and preset wafer template information.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the steps of the method according to any one of claims 7 to 9 are implemented.

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