Wafer alignment method and apparatus based on machine vision, and device and medium

Abstract

A wafer alignment method and apparatus based on machine vision, and a device and a medium. The method comprises: on the basis of a tray image obtained by means of rotating an electric motor, determining the position of a rotation center of a tray (S110), wherein a reference circle scale line having a radius greater than the radius of a target wafer is engraved on the tray; placing the target wafer in the reference circle scale line on the tray, and performing image collection on the tray, so as to obtain a target image (S120); on the basis of the target image, and on the basis of the distance between the reference circle scale line and the target wafer, determining the position of a circle center of the wafer (S130); on the basis of the target image, and on the basis of the reference wafer scale line, the position of the circle center of the wafer and wafer notch identification information, determining an offset angle of the wafer (S140); and on the basis of the position of the rotation center of the tray, the position of the circle center of the wafer and the offset angle of the wafer, performing position alignment on a test point on the target wafer (S150).

Description

Machine vision-based wafer calibration methods, devices, equipment, and media

[0001] This application claims priority to Chinese Patent Application No. 202411577024.3, filed with the Chinese Patent Office on November 6, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of wafer calibration technology, and for example to a wafer calibration method, apparatus, device and medium based on machine vision. Background Technology

[0003] Four-probe resistance meters are used in semiconductor manufacturing processes to measure the sheet resistance or resistivity of thin films such as implanted, diffused, epitaxial, and metal-coated films. A fully automated four-probe resistance meter typically consists of a wafer carrier, a robotic arm, a wafer calibrator, and a measurement unit. Because there is a certain gap between the wafers placed within the wafer carrier, and wafer notches (or gaps) are random, and wafer operations at the process station require precision down to the specific location, calibration of the wafer center point and the wafer notch (or gap) is necessary to ensure the accuracy of wafer operations at the process station.

[0004] The relevant technology uses a wafer calibrator in a fully automated four-probe resistance meter to calibrate the wafer's position. The wafer calibrator is a device for locating the wafer center and wafer edge (or notch). The robotic arm in the fully automated four-probe resistance meter places the wafer on the wafer calibrator. The calibrator rotates, and by identifying the position of the wafer edge (or notch), it adjusts the wafer center point deviation and the orientation of the wafer edge (or notch). The robotic arm then removes the wafer from the calibrator and places it on the process station. After the wafer finishes its work on the process station, the robotic arm removes the wafer from the process station and places it back on the wafer carrier. To continue working, the wafer must be removed from the wafer carrier again, placed on the wafer calibrator for calibration, and then placed back on the process station. This complex process from calibration to operation negatively impacts wafer utilization efficiency. Summary of the Invention

[0005] This application provides a machine vision-based wafer calibration method, apparatus, device, and medium to improve wafer calibration efficiency and avoid the need for repeated wafer retrieving operations from the wafer carrier to the wafer calibrator and then to the process station during wafer calibration.

[0006] According to one aspect of this application, a machine vision-based wafer calibration method is provided, comprising:

[0007] The position of the tray rotation center is determined based on the tray image obtained from the motor rotation; wherein, the tray is engraved with reference circle scale lines with a radius larger than the radius of the target wafer;

[0008] The target wafer is placed within the reference circle scale line on the tray, and an image of the tray is acquired to obtain the target image;

[0009] Based on the target image, the position of the wafer center is determined according to the distance between the reference circular scale line and the target wafer;

[0010] Based on the target image, the wafer offset angle is determined according to the reference circle scale line, the wafer center position, and the wafer notch identification information.

[0011] The test points on the target wafer are calibrated based on the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

[0012] According to another aspect of this application, a machine vision-based wafer calibration apparatus is provided, comprising:

[0013] The rotation center determination module is configured to determine the rotation center position of the tray based on the tray image obtained by the motor rotation; wherein, the tray is engraved with a reference circle scale line with a radius larger than the radius of the target wafer;

[0014] The wafer image acquisition module is configured to place the target wafer within the reference circle scale line on the tray and acquire an image of the tray to obtain the target image;

[0015] The wafer center position determination module is configured to determine the wafer center position based on the target image and the distance between the reference circular scale line and the target wafer.

[0016] The wafer offset angle determination module is configured to determine the wafer offset angle based on the target image, according to the reference circle scale line, the wafer center position, and wafer notch identification information.

[0017] The position calibration module is configured to calibrate the position of the test points on the target wafer based on the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

[0018] According to another aspect of this application, an electronic device is provided, comprising:

[0019] At least one processor; and

[0020] A memory communicatively connected to the at least one processor; wherein,

[0021] The memory stores a computer program that can be executed by the at least one processor, which enables the at least one processor to perform the machine vision-based wafer calibration method described in any embodiment of this application.

[0022] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement the machine vision-based wafer calibration method described in any embodiment of this application. Attached Figure Description

[0023] Figure 1 is a flowchart of a machine vision-based wafer calibration method according to Embodiment 1 of this application;

[0024] Figure 2 is a flowchart of another machine vision-based wafer calibration method provided according to Embodiment 2 of this application;

[0025] Figure 3 is a schematic diagram of the reference circular scale lines and vertical positioning points;

[0026] Figure 4 is a schematic diagram of a wafer calibration device based on machine vision according to Embodiment 3 of this application;

[0027] Figure 5 is a schematic diagram of the structure of an electronic device that implements the machine vision-based wafer calibration method according to the embodiments of this application. Detailed Implementation

[0028] The terms "first," "second," "target," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, including processes, methods, systems, products, or devices that, in addition to comprising the series of steps or units shown in the embodiments of this application, may also include processes, methods, systems, products, or devices that do not explicitly list such series of steps or units, or other steps or units inherent to such processes, methods, systems, products, or devices.

[0029] Example 1

[0030] Figure 1 is a flowchart of a machine vision-based wafer calibration method provided in Embodiment 1 of this application. This embodiment is applicable to calibrating the center position and notch angle of a wafer. The method can be executed by a machine vision-based wafer calibration device, which can be implemented in hardware and / or software and can be configured in a device with computing capabilities. As shown in Figure 1, the method includes:

[0031] S110. Determine the position of the center of rotation of the pallet based on the image of the pallet obtained from the motor rotation.

[0032] In this embodiment of the application, a reference circle scale line with a radius larger than that of the target wafer is engraved on the tray.

[0033] A tray is a platform on a wafer fabrication unit used to place wafers, allowing for wafer manipulation at that unit. A motor is a control device that rotates the tray, adjusting the position of the wafers placed on it.

[0034] Typically, a motor drives a tray to rotate, and the tray is fixed to the motor's rotating shaft by structural components. Due to factors such as installation gaps and installation errors, the center of the tray and the center of rotation of the tray are not in the same position, resulting in an error. Therefore, in order to ensure the accuracy of subsequent calibration, it is necessary to calibrate the deviation between the center of the tray and the center of rotation of the tray.

[0035] For example, the position of the tray rotation center is determined based on the position change information of the tray center when the motor rotates. The tray center can be determined by a fixed reference center point mark on the tray, or by the result of a circle fitting of the tray.

[0036] In this embodiment, a reference circular scale line is etched on the tray. The reference circular scale line has its origin at the center of the tray. The radius of the reference circular scale line is larger than the radius of the target wafer. The difference between the radius of the reference circular scale line and the radius of the target wafer is greater than a first difference and less than a second difference. The values ​​of the first difference and the second difference can be determined based on the actual tray size and the target wafer size. For example, the difference between the radius of the reference circular scale line and the radius of the target wafer is 5 millimeters (mm).

[0037] In some feasible embodiments, S110 includes:

[0038] Acquire an image of the first tray when the motor rotates to the first angle, fit the tray position based on the first tray image, and determine the center position of the first tray based on the fitting result;

[0039] The second tray image is acquired when the motor rotates to the second angle. The tray position is fitted based on the second tray image, and the center position of the second tray is determined based on the fitting result. The difference between the second angle and the first angle is a preset angle.

[0040] The center position of the tray rotation is determined based on the center position of the first tray, the center position of the second tray, and the preset angle.

[0041] For example, an image acquisition device, such as a camera, is installed above the process station to acquire images of the tray and the target wafer on it, for visual calibration based on the acquired images. The installation requirements for the image acquisition device are that the center of the image acquisition device, the center of the light source, and the center of the tray are on the same axis, and the planes of the image acquisition device, the light source, and the tray are horizontal. The light source is used to provide supplementary lighting during image acquisition to ensure image clarity.

[0042] When the motor rotates to the first angle, an image of the tray is captured, resulting in the first tray image. A circle is fitted to the tray in the first image, and the center of the fitted circle is the center position of the first tray. Similarly, when the motor rotates to the second angle, an image of the tray is captured, resulting in the second tray image. A circle is fitted to the tray in the second image, and the center of the fitted circle is the center position of the second tray. If the tray center coincides with the tray rotation center, then the first and second tray center positions are the same. If the first and second tray center positions differ, it indicates an error between the tray center and the tray rotation center. The position of the tray rotation center can be determined based on the difference between the second and first angles, i.e., the positional relationship between the preset angle and the change in the tray center position. For example, the preset angle is 90 degrees.

[0043] For example, when the motor rotates 0 degrees, an image of the tray is captured, resulting in a first tray image. A circle is fitted to the tray in the first image, and the center of the fitted circle is the center position of the first tray, p1(p1.x, p1.y). Similarly, when the motor rotates 180 degrees, an image of the tray is captured, resulting in a second tray image. A circle is fitted to the tray in the second image, and the center of the fitted circle is the center position of the second tray, p2(p2.x, p2.y). Since the two rotations of the motor differ by 180 degrees, the centers of the first and second trays are symmetrical about the center of rotation. Therefore, the center of rotation of the tray can be p((p1.x + p2.x) / 2, (p1.y + p2.y) / 2).

[0044] In some implementations, for other preset angles, the position of the pallet rotation center can be inferred from the positional relationship between the other preset angles and the change in the pallet center position. For example, when the preset angle is 90 degrees, pallet images can be acquired when the motor rotates 0 degrees and 90 degrees respectively, and the pallet center positions p1' and p2' can be obtained by performing circle fitting on these two pallet images. Since the pallet center (i.e., the center of the reference circle) moves in a circle around the rotation center, the distances from p1' and p2' to the rotation center are equal, and the line connecting p1' and p2' to the rotation center is perpendicular (the vector dot product is 0). By solving these two sets of geometric relationship equations, the coordinates of the pallet rotation center position can be obtained.

[0045] Optionally, multiple preset angles can be used to obtain multiple pallet rotation center positions, and errors can be reduced by taking the average value to ensure the accuracy of the pallet rotation center position determination.

[0046] S120. Place the target wafer within the reference circle scale line on the tray and acquire an image of the tray to obtain the target image.

[0047] In some embodiments, a robotic arm can be controlled to place the target wafer within the reference circular scale lines. For example, based on the position information of the robotic arm, the position information of the tray, and the position information of the reference circular scale lines, the positional movement information of the robotic arm is determined. When placing the target wafer according to this positional movement information, the robotic arm can be controlled to place the target wafer within the reference circular scale lines on the tray. Alternatively, the target wafer can be placed within the reference circular scale lines on the tray using image recognition results acquired by an image acquisition device. After the target wafer is placed, the tray is photographed to obtain a target image.

[0048] S130. Based on the target image, determine the position of the wafer center according to the distance between the reference circular scale line and the target wafer.

[0049] Since both the reference circular scale line and the target wafer are circular, the center position of the target wafer can be determined based on the positional relationship between them. For example, using image recognition information from the target image, the position of a point passing through the center can be determined based on the distance between the reference circular scale line and the target wafer, and then the center position of the wafer can be determined based on this point.

[0050] S140. Based on the target image, determine the wafer offset angle according to the reference circle scale line, the wafer center position, and the wafer notch identification information.

[0051] Wafer offset angle refers to the angle at which a notch on a wafer deviates from the horizontal or vertical direction. For example, the horizontal or vertical direction is determined based on the wafer center position and a reference circular scale line. Then, the angle between the line connecting the notch and the wafer center position and the horizontal or vertical direction is determined based on the wafer notch identification information in the target image.

[0052] S150. The test points on the target wafer are calibrated according to the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

[0053] Test points on the target wafer refer to multiple fixed points that are pre-marked on the target wafer.

[0054] In some embodiments, position calibration of test points on the target wafer can eliminate offsets and angular deviations to ensure accurate positioning of test points, providing a precise positioning reference for subsequent process operations (such as probe contact during four-probe resistance measurement).

[0055] For example, the center point offset is determined based on the center position of the tray rotation and the center position of the wafer. Then, the initial test point position is calibrated based on the center point offset and the wafer offset angle. The position calculations for the rotary motor and linear motion motor are performed based on the calibrated test point positions. For example, multiple test points include a test sequence, and the position calculations are performed sequentially according to the test sequence.

[0056] For example, the position of test points on the target wafer can be calibrated based on the following formula, according to the position of the tray rotation center, the position of the wafer center, and the wafer offset angle:

[0057] ;

[0058] Where (x1, y1) is the initial test point position on the target wafer, (x2, y2) is the calibration test point position, (dx, dy) is the center point offset, and θ is the wafer offset angle.

[0059] In some embodiments, the center point offset (dx, dy) is located in a unified coordinate system established by the image acquisition device, where dx is the difference in x-axis coordinate between the center of tray rotation and the center of wafer, and dy is the difference in y-axis coordinate between the center of tray rotation and the center of wafer.

[0060] This application embodiment achieves wafer calibration through simple machine vision operations, which improves the calibration accuracy and efficiency of wafer calibration. It avoids the need to repeatedly pick up and drop the wafer from the process station to the calibrator during wafer calibration, reducing the calibration operation process. Directly calibrating the wafer at the process station also reduces the space required for wafer calibration.

[0061] Example 2

[0062] Figure 2 is a flowchart of a machine vision-based wafer calibration method provided in Embodiment 2 of this application. This embodiment is an improvement on Embodiment 1 described above. As shown in Figure 2, the method includes:

[0063] S210. Determine the position of the center of rotation of the pallet based on the image of the pallet obtained from the rotation of the motor.

[0064] The tray is engraved with a reference circle scale line with a radius larger than that of the target wafer. The reference circle scale line includes two vertical positioning points, and the line connecting the two vertical positioning points passes through the center of the tray.

[0065] The line connecting the vertical positioning points is the vertical diameter on the reference circle scale line, used for reference positioning of the wafer placement position, improving the efficiency of determining the wafer offset angle. Figure 3 shows a schematic diagram of the reference circle scale line and the vertical positioning points, where points A and C are two vertical positioning points.

[0066] S220. Based on the notch of the target wafer and using the target vertical positioning point as a reference point, place the target wafer on the tray and acquire an image of the tray to obtain the target image.

[0067] For example, the target vertical positioning point is the lower vertical positioning point among the two vertical positioning points.

[0068] As shown in Figure 3, point C is the target vertical positioning point. In order to facilitate the subsequent determination of the wafer offset angle, the notch of the target wafer is aligned with the target vertical positioning point and the target wafer is placed. Due to the deviation, the position of the notch of the target wafer is close to but does not coincide with the target vertical positioning point.

[0069] S230. Based on the recognition results of the target image, determine the maximum and minimum distances between the reference circular scale line and the target wafer; based on the line connecting the reference circular scale line corresponding to the maximum distance and the target wafer, determine the maximum distance point on the target wafer; based on the line connecting the reference circular scale line corresponding to the minimum distance and the target wafer, determine the minimum distance point on the target wafer; based on the maximum and minimum distance points, determine the wafer center position.

[0070] The target wafer is located within the reference circle's scale lines. The distances between each point on the reference circle's scale lines and the target wafer are determined sequentially. The maximum and minimum distances are then determined. The point on the target wafer corresponding to the maximum distance is the maximum distance point, and the point on the target wafer corresponding to the minimum distance is the minimum distance point. As shown in Figure 3, point E is the maximum distance point, and point F is the minimum distance point. Based on the characteristics of a circle, the line connecting the maximum and minimum distance points passes through the center of the circle. That is, the line connecting the maximum and minimum distance points is the diameter of the target wafer. Based on the positional information of the maximum and minimum distance points, the midpoint (or the average of the coordinates of the two points) of the line connecting the maximum and minimum distance points is taken to determine the position of the wafer's center.

[0071] In some embodiments, determining the maximum and minimum distances between the reference circular scale line and the target wafer includes:

[0072] Traverse each point on the reference circular scale line as the target reference point;

[0073] Determine the shortest distance between the target reference point and the target wafer, and use the shortest distance as the target distance between the target reference point and the target wafer;

[0074] The maximum and minimum distances are determined from the target distance between the target reference point and the target wafer.

[0075] The distance between each point on the reference circle scale and the target wafer is determined. For example, when determining a point, that point is used as the target reference point. The shortest distance between the target reference point and each point on the target wafer is the target distance between the target reference point and the target wafer. The target distances between each point on the reference circle scale and the target wafer are obtained. The target distances are sorted according to the target distances to obtain the maximum distance and the minimum distance.

[0076] In some embodiments, before determining the wafer center position based on the maximum and minimum distance points, the method further includes:

[0077] Determine if the maximum distance point is located at the wafer notch location;

[0078] The maximum distance point is redefined in response to the maximum distance point being located at the wafer notch position;

[0079] Accordingly, after determining the wafer center position based on the maximum and minimum distance points, the method further includes:

[0080] Determine the positional offset between the wafer center and the tray rotation center;

[0081] In response to a position offset greater than a preset offset threshold, the operation of placing the target wafer within the reference circle scale line on the tray is re-executed to recalibrate the target wafer.

[0082] After determining the maximum distance point on the target wafer, it is determined whether the maximum distance point is located at the wafer notch. If the maximum distance point is located at the wafer notch, it will cause inaccurate identification of the wafer center position. Therefore, the maximum distance point can be judged. If the maximum distance point is located at the wafer notch, the maximum distance point is re-determined.

[0083] In some embodiments, to avoid identification errors based on the wafer notch position and to prevent the maximum distance point from falling exactly on the wafer notch position when placing the wafer, after determining the wafer center position based on the maximum and minimum distance points, the positional offset between the wafer center position and the tray rotation center position is determined. If the positional offset is large, it proves that the wafer center position is incorrectly determined, that is, the maximum and minimum distance points are not accurately positioned. In this case, the target wafer is repositioned and the calibration process is re-executed to improve the accuracy of the wafer center position determination.

[0084] S240. Determine the wafer notch position based on the wafer notch identification information of the target image; determine the target positioning line based on the position of the two vertical positioning points on the reference circle scale line; determine the offset line based on the wafer center position and the wafer notch position; determine the angle between the target positioning line and the offset line as the wafer offset angle.

[0085] Image recognition is performed on the target image based on the wafer notch features to obtain the wafer notch location. If the wafer notch is a region, the center point of the identified notch region is taken as the wafer notch location. The positions of two vertical positioning points on the reference circle scale line (points A and C as shown in Figure 3) are connected to form the target positioning line. The wafer center position and the wafer notch position are connected to form the offset line. The angle between the target positioning line and the offset line is determined as the wafer offset angle.

[0086] In other embodiments, as shown in FIG3, the reference circular scale line may also include two horizontal positioning points (such as point B and point H which is horizontally opposite to point B) to determine the horizontal target positioning line based on the two horizontal positioning points, and to determine the wafer offset angle based on the angle between the horizontal target positioning line and the offset line.

[0087] S250. Determine the initial test point position on the target wafer; determine the center point offset based on the tray rotation center position and the wafer center position; calibrate the initial test point position based on the center point offset and the wafer offset angle to obtain the calibrated test point position.

[0088] A unified coordinate system is established based on the image acquisition device. All positions in this embodiment are in the same coordinate system to ensure the accuracy of position information determination and improve computational efficiency. Test points on the target wafer are determined, and the initial test point positions of each test point in the camera coordinate system are determined. The center point offset is determined based on the position of the tray rotation center and the wafer center position. Then, the initial test point positions are calibrated based on the center point offset and the wafer offset angle to obtain calibrated test point positions, so that the motor shaft can be motion controlled based on the calibrated test point positions.

[0089] For example, the initial test point position can be calibrated based on the center point offset and wafer offset angle using the following formula, including:

[0090] ;

[0091] Where (x1, y1) is the initial test point position, (x2, y2) is the calibration test point position, (dx, dy) is the center point offset, and θ is the wafer offset angle.

[0092] In this embodiment of the application, by determining the position of the wafer center and calibrating other machine vision angles, calibration errors can be effectively detected during the calibration process, thereby improving calibration accuracy.

[0093] Example 3

[0094] Figure 4 is a schematic diagram of a machine vision-based wafer calibration device provided in Embodiment 3 of this application. As shown in Figure 4, the device includes:

[0095] The rotation center determination module 410 is configured to determine the rotation center position of the tray based on the tray image obtained by the motor rotation; wherein, the tray is engraved with a reference circle scale line with a radius larger than the radius of the target wafer;

[0096] The wafer image acquisition module 420 is configured to place the target wafer within the reference circle scale line on the tray and acquire an image of the tray to obtain the target image;

[0097] The wafer center position determination module 430 is configured to determine the wafer center position based on the target image and the distance between the reference circular scale line and the target wafer.

[0098] The wafer offset angle determination module 440 is configured to determine the wafer offset angle based on the target image, according to the reference circle scale line, the wafer center position, and wafer notch identification information.

[0099] The position calibration module 450 is configured to calibrate the position of the test points on the target wafer based on the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

[0100] This application embodiment achieves wafer calibration through simple machine vision operations, which improves the calibration accuracy and efficiency of wafer calibration. It avoids the need to repeatedly pick up and drop the wafer from the process station to the calibrator during wafer calibration, reducing the calibration operation process. Directly calibrating the wafer at the process station also reduces the space required for wafer calibration.

[0101] Optional, the wafer center location determination module includes:

[0102] The distance determination unit is configured to determine the maximum and minimum distances between the reference circular scale line and the target wafer based on the recognition result of the target image.

[0103] The first distance point determination unit is configured to determine the maximum distance point on the target wafer based on the line connecting the reference circular scale line corresponding to the maximum distance and the target wafer.

[0104] The second distance point determination unit is configured to determine the minimum distance point on the target wafer based on the line connecting the reference circular scale line corresponding to the minimum distance and the target wafer.

[0105] The center position determination unit is configured to determine the center position of the wafer based on the maximum distance point and the minimum distance point.

[0106] Optionally, the distance determination unit is set to:

[0107] Traverse each point on the reference circular scale line as the target reference point;

[0108] Determine the shortest distance between the target reference point and the target wafer, and use the shortest distance as the target distance between the target reference point and the target wafer;

[0109] The maximum and minimum distances are determined from the target distance between the target reference point and the target wafer.

[0110] Optionally, the wafer center location determination module also includes a distance point determination unit, configured as follows:

[0111] Before determining the wafer center position based on the maximum and minimum distance points.

[0112] Determine whether the maximum distance point is located at the wafer notch position;

[0113] In response to the maximum distance point being located at the wafer notch position, the maximum distance point is redefined;

[0114] Accordingly, the device also includes a position offset determination module, configured as follows:

[0115] After determining the wafer center position based on the maximum and minimum distance points,

[0116] Determine the positional offset between the wafer center position and the tray rotation center position;

[0117] In response to the position offset being greater than a preset offset threshold, the operation of placing the target wafer within the reference circle scale line on the tray is re-executed to recalibrate the target wafer.

[0118] Optionally, the reference circular scale line includes two vertical positioning points, and the line connecting the two vertical positioning points passes through the center of the tray.

[0119] Correspondingly, the wafer image acquisition module is configured as follows:

[0120] Based on the notch of the target wafer and using the target vertical positioning point as a reference point, the target wafer is placed on a tray; wherein, the target vertical positioning point is the lower vertical positioning point among the two vertical positioning points;

[0121] Correspondingly, the wafer offset angle determination module is set as follows:

[0122] The wafer notch location is determined based on the wafer notch identification information of the target image;

[0123] The target positioning line is determined based on the positions of two vertical positioning points on the reference circular scale line;

[0124] The offset line is determined based on the wafer center position and the wafer notch position;

[0125] The angle between the target positioning line and the offset line is determined as the wafer offset angle.

[0126] Optionally, the position calibration module is configured as follows:

[0127] Determine the initial test point positions on the target wafer;

[0128] The center point offset is determined based on the position of the tray rotation center and the position of the wafer center.

[0129] The initial test point position is calibrated based on the center point offset and the wafer offset angle to obtain the calibrated test point position.

[0130] The initial test point position is calibrated based on the center point offset and the wafer offset angle according to the following formula, including:

[0131] ;

[0132] Where (x1, y1) is the initial test point position, (x2, y2) is the calibration test point position, (dx, dy) is the center point offset, and θ is the wafer offset angle.

[0133] Optionally, the rotation center determination module is set to:

[0134] Acquire an image of the first tray when the motor rotates at a first angle, fit the tray position based on the first tray image, and determine the center position of the first tray based on the fitting result.

[0135] A second tray image is acquired when the motor rotates to the second angle. The tray position is fitted based on the second tray image, and the center position of the second tray is determined based on the fitting result. The difference between the second angle and the first angle is a preset angle.

[0136] The center position of the tray rotation is determined based on the center position of the first tray, the center position of the second tray, and a preset angle.

[0137] The machine vision-based wafer calibration device provided in this application embodiment can execute the machine vision-based wafer calibration method provided in any embodiment of this application, and has the corresponding functional modules and beneficial effects of executing the method.

[0138] The acquisition, storage, use, and processing of data in this application comply with relevant national laws and regulations and do not violate public order and good morals.

[0139] Example 4

[0140] According to embodiments of this disclosure, this disclosure also provides an electronic device, a readable storage medium, and a computer program product.

[0141] Figure 5 shows a schematic diagram of the structure of an electronic device 10 that can be used to implement embodiments of this application. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples.

[0142] As shown in Figure 5, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0143] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0144] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 may include a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as machine vision-based wafer calibration methods.

[0145] In some embodiments, the machine vision-based wafer calibration method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or mounted on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the machine vision-based wafer calibration method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the machine vision-based wafer calibration method by any other suitable means (e.g., by means of firmware).

[0146] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard parts (ASSPs), system-on-chips (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0147] Computer programs used to implement the methods of this application may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0148] In the context of this application, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. Examples of machine-readable storage media may include electrical connections based on one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, compact disc-read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0149] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a cathode ray tube (CRT), liquid crystal display (LCD), or monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0150] The systems and technologies described herein can be implemented in computing systems that include back-end components (e.g., as data servers), or computing systems that include switching components (e.g., application servers), or computing systems that include front-end components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such back-end, switching, or front-end components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0151] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system. It addresses the shortcomings of traditional physical hosts and Virtual Private Server (VPS) services, such as high management difficulty and weak business scalability.

[0152] The various processes shown above can be used to reorder, add, or delete steps. For example, the multiple steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved.

Claims

1. A machine vision-based wafer calibration method, comprising: The position of the tray rotation center is determined based on the tray image obtained from the motor rotation; wherein, the tray is engraved with reference circle scale lines with a radius larger than the radius of the target wafer; The target wafer is placed within the reference circle scale line on the tray, and an image of the tray is acquired to obtain the target image; Based on the target image, the position of the wafer center is determined according to the distance between the reference circular scale line and the target wafer; Based on the target image, the wafer offset angle is determined according to the reference circle scale line, the wafer center position, and the wafer notch identification information. The test points on the target wafer are calibrated based on the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

2. The method according to claim 1, wherein, Based on the target image, determining the wafer center position according to the distance between the reference circular scale line and the target wafer includes: Based on the recognition results of the target image, determine the maximum and minimum distances between the reference circular scale line and the target wafer; The maximum distance point on the target wafer is determined based on the line connecting the reference circular scale line corresponding to the maximum distance and the target wafer. The minimum distance point on the target wafer is determined based on the line connecting the reference circular scale line corresponding to the minimum distance and the target wafer. The wafer center position is determined based on the maximum and minimum distance points.

3. The method according to claim 2, wherein, Determining the maximum and minimum distances between the reference circular scale line and the target wafer includes: Traverse each point on the reference circular scale line as the target reference point; Determine the shortest distance between the target reference point and the target wafer, and use the shortest distance as the target distance between the target reference point and the target wafer; The maximum and minimum distances are determined from the target distance between the target reference point and the target wafer.

4. The method according to claim 2 or 3, before determining the wafer center position based on the maximum distance point and the minimum distance point, the method further includes: Determine whether the maximum distance point is located at the wafer notch position; In response to the maximum distance point being located at the wafer notch position, the maximum distance point is redefined; After determining the wafer center position based on the maximum and minimum distance points, the method further includes: Determine the positional offset between the wafer center position and the tray rotation center position; In response to the position offset being greater than a preset offset threshold, the operation of placing the target wafer within the reference circle scale line on the tray is re-executed to recalibrate the target wafer.

5. The method according to claim 1, wherein, The reference circular scale line includes two vertical positioning points, and the line connecting the two vertical positioning points passes through the center of the tray. Placing the target wafer within the reference circle scale lines on the tray includes: Based on the notch of the target wafer and using the target vertical positioning point as a reference point, the target wafer is placed on a tray; wherein, the target vertical positioning point is the lower vertical positioning point among the two vertical positioning points; Based on the target image, the wafer offset angle is determined according to the reference circular scale line, the wafer center position, and the wafer notch identification information, including: The wafer notch location is determined based on the wafer notch identification information of the target image; The target positioning line is determined based on the positions of two vertical positioning points on the reference circular scale line; The offset line is determined based on the wafer center position and the wafer notch position; The angle between the target positioning line and the offset line is determined as the wafer offset angle.

6. The method according to claim 1, wherein, The test points on the target wafer are calibrated based on the tray rotation center position, the wafer center position, and the wafer offset angle, including: Determine the initial test point positions on the target wafer; The center point offset is determined based on the position of the tray rotation center and the position of the wafer center. The initial test point position is calibrated based on the center point offset and the wafer offset angle to obtain the calibrated test point position. The initial test point position is calibrated based on the center point offset and the wafer offset angle according to the following formula, including: ； Where (x1, y1) is the initial test point position, (x2, y2) is the calibration test point position, (dx, dy) is the center point offset, and θ is the wafer offset angle.

7. The method according to claim 1, wherein, The position of the tray rotation center is determined based on the image of the tray obtained from the motor rotation, including: Acquire an image of the first tray when the motor rotates at a first angle, fit the tray position based on the first tray image, and determine the center position of the first tray based on the fitting result. A second tray image is acquired when the motor rotates to the second angle. The tray position is fitted based on the second tray image, and the center position of the second tray is determined based on the fitting result. The difference between the second angle and the first angle is a preset angle. The center position of the tray rotation is determined based on the center position of the first tray, the center position of the second tray, and the preset angle.

8. A machine vision-based wafer calibration device, comprising: The rotation center determination module is configured to determine the rotation center position of the tray based on the tray image obtained by the motor rotation; wherein, the tray is engraved with a reference circle scale line with a radius larger than the radius of the target wafer; The wafer image acquisition module is configured to place the target wafer within the reference circle scale line on the tray and acquire an image of the tray to obtain the target image; The wafer center position determination module is configured to determine the wafer center position based on the target image and the distance between the reference circular scale line and the target wafer. The wafer offset angle determination module is configured to determine the wafer offset angle based on the target image, according to the reference circle scale line, the wafer center position, and wafer notch identification information. The position calibration module is configured to calibrate the position of the test points on the target wafer based on the position of the tray rotation center, the position of the wafer center, and the wafer offset angle.

9. An electronic device, comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor to enable the at least one processor to perform the machine vision-based wafer calibration method according to any one of claims 1-7.

10. A computer-readable storage medium storing computer instructions for causing a processor to execute the machine vision-based wafer calibration method according to any one of claims 1-7.

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