Wafer positioning method and apparatus

Abstract

The present disclosure relates to a wafer positioning method and device. A global image of a standard wafer can be acquired based on a low magnification lens, and template images of a plurality of target regions in the global image can be acquired based on a high magnification lens, so as to jointly use the low magnification lens and the high magnification lens to ensure that the template images have both a field of view range and positioning accuracy. Next, target images of the target regions on a correction wafer are acquired by the high magnification lens, and initial center positions of the template images in the corresponding target images are determined, so as to perform wafer coarse positioning to achieve the purposes of reducing a search range and adapting to errors. Then, target center positions of the template images in corresponding search regions are determined, so as to perform wafer fine positioning to solve the problem of image angle deviation, thereby improving the matching robustness under a complex attitude. Finally, offset parameters of the correction wafer are determined based on a target affine transformation matrix, so as to not only achieve wafer positioning with micron-level accuracy, but also ensure subsequent process operations of the wafer.

Description

TECHNICAL FIELD

[0001] Embodiments of the present specification belong to the technical field of semiconductor manufacturing, and particularly relate to a wafer positioning method and device. BACKGROUND

[0002] A semiconductor wafer can be understood as a very thin, highly flat and extremely smooth surface of a circular silicon chip (or other semiconductor material), which is the basic material for manufacturing semiconductor devices and integrated circuits (ICs), and can be regarded as the "foundation" of a chip.

[0003] In the production process of a semiconductor wafer, a mechanical arm is usually controlled to perform pick-and-place operations on the semiconductor wafer based on cassette positioning or edge positioning, and the error range of such wafer positioning method is in the order of millimeters. However, subsequent processes such as die packaging and detection on the semiconductor wafer require extremely high positioning accuracy, which needs to control the error in the order of microns. The current positioning technology mainly uses a single magnification lens to achieve the positioning, which has the problems of insufficient accuracy or low efficiency, thereby affecting the subsequent process operations of the semiconductor wafer. SUMMARY

[0004] Embodiments of the present disclosure provide a wafer positioning method and device.

[0005] In a first aspect of the present disclosure, a wafer positioning method is provided. The method includes obtaining a global image of a standard wafer based on a low magnification lens, and obtaining template images corresponding to at least four target regions in the global image based on a high magnification lens, each template image having a corresponding standard center position. The method further includes obtaining target images corresponding to the target regions on a correction wafer based on the high magnification lens, and determining initial center positions of each template image in the corresponding target image. The method further includes determining search regions in the corresponding target image based on size parameters of each template image and the corresponding initial center positions, and determining target center positions of each template image in the corresponding search region. In addition, the method further includes determining a target affine transformation matrix based on the standard center positions and the target center positions of all template images, and determining offset parameters of the correction wafer based on the target affine transformation matrix.

[0006] In a second aspect of the present disclosure, a wafer positioning apparatus is provided. The apparatus comprises an image acquisition module configured to acquire a global image of a standard wafer based on a low magnification lens, and acquire a template image corresponding to each of at least four target regions in the global image based on a high magnification lens, each template image having a corresponding standard center position. The apparatus further comprises a position determination module configured to acquire a target image corresponding to each of the target regions on a correction wafer based on the high magnification lens, and determine an initial center position of each template image in the corresponding target image. The apparatus further comprises a position calculation module configured to determine a search region in the corresponding target image based on a size parameter of each template image and the corresponding initial center position, and determine a target center position of each template image in the corresponding search region. In addition, the apparatus further comprises a parameter generation module configured to determine a target affine transformation matrix based on the standard center positions and the target center positions of all template images, and determine an offset parameter of the correction wafer based on the target affine transformation matrix.

[0007] In a third aspect of the present disclosure, a computer program product is provided, comprising a computer program executable by a processor to implement the method according to the first aspect.

[0008] In a fourth aspect of the present disclosure, a machine readable storage medium is provided. The machine readable storage medium has stored thereon machine executable instructions, wherein the machine executable instructions are executable by a processor to implement the method provided by the first aspect of the present disclosure.

[0009] It should be understood that the description in the summary is not intended to identify key or essential features of embodiments of the present disclosure or limit the scope of the present disclosure. Other features, aspects, and advantages of the present disclosure will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0010] The above and other features, aspects and advantages of embodiments of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings. In the drawings:

[0011] Figure 1 a schematic diagram showing an example environment in which some embodiments of the present disclosure can be implemented;

[0012] Figure 2 a flowchart showing a wafer positioning method according to some embodiments of the present disclosure;

[0013] Figure 3 a schematic diagram showing a global image marked with target regions according to some embodiments of the present disclosure;

[0014] Figure 4A global image schematic diagram marked with a set of target regions and template regions of some embodiments of the present disclosure is shown.

[0015] Figure 5 A wafer positioning effect schematic diagram of some embodiments of the present disclosure is shown.

[0016] Figure 6 A block diagram of a wafer positioning device of some embodiments of the present disclosure is shown.

[0017] Figure 7 A block diagram of an electronic device that can implement a plurality of embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0018] For the purposes of the present application, the term “coupled” is used to describe both an indirect coupling and a direct coupling between two entities, where such an indirect or direct coupling can be through a wired or wireless medium and where the coupling applies to all possible combinations of the elements. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. It is to be further understood that the terms “approximately,” “substantially,” and “about” are used herein to represent an acceptable quality, value, quantity, fact, or state of being sufficiently close to that which is described to experimentally or otherwise verify the desired characteristics of an embodiment of the present disclosure as described herein are met or exceeded. Precise

[0019] The terms “include,” “includes” and “including” as used in the specification and the claims and above and below are intended to be inclusive, in contrast to “comprising” or “comprises,” which are exclusive. For example, a process, method, system, product, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements but can include other steps or elements not expressly listed or inherent to such process, method, system, product, or apparatus. Depending on the context, the word “if’ as used herein can be interpreted to mean “when” or “in response to determining” or “in response to detecting.”

[0020] As described above, the subsequent processes such as die encapsulation and detection on the semiconductor wafer have very high positioning accuracy requirements, and usually need to control the error to the micron level. The current positioning technology is mainly realized through a single magnification lens, which is difficult to balance between a large field of view and high-precision detection. For example, when a low magnification lens is used for wafer positioning, although a larger field of view of the wafer area can be covered, the overall resolution is insufficient, which can easily lead to insufficient accuracy of wafer positioning. For another example, when a high magnification lens is used for wafer positioning, although the positioning accuracy can be ensured to a certain extent, the field of view is limited, and multiple shots are needed to obtain a complete wafer image, which leads to low efficiency of wafer positioning, and further affects the subsequent processes such as die encapsulation and detection on the wafer.

[0021] To this end, embodiments of the present disclosure propose a wafer positioning method. The method comprises obtaining a global image of a standard wafer based on a low magnification lens, and obtaining template images corresponding to at least four target regions in the global image based on a high magnification lens, each template image having a corresponding standard center position. The method further comprises obtaining target images corresponding to the target regions on a correction wafer based on the high magnification lens, and determining initial center positions of each template image in the corresponding target images. The method further comprises determining search regions in the corresponding target images based on size parameters of each template image and the corresponding initial center positions, and determining target center positions of each template image in the corresponding search regions. In addition, the method further comprises determining a target affine transformation matrix based on the standard center positions and the target center positions of all template images, and determining offset parameters of the correction wafer based on the target affine transformation matrix.

[0022] In this way, the global image of the standard wafer can be obtained based on the low magnification lens, and the template images corresponding to the multiple target regions in the global image can be obtained based on the high magnification lens, so as to jointly use the low magnification lens and the high magnification lens to ensure that the template images have both a field of view range and positioning accuracy. Secondly, by determining the initial center positions of each template image in the corresponding target images, coarse positioning of the wafer is performed to achieve the purposes of reducing the search range and adapting to errors. In addition, by determining the target center positions of each template image in the corresponding search regions, fine positioning of the wafer is performed to solve the image angle offset problem, thereby improving the matching robustness under complex postures. Furthermore, the offset parameters of the correction wafer are determined based on the target affine transformation matrix, which not only realizes wafer positioning with micron-level accuracy, but also brings guarantee for subsequent process operations of the wafer.

[0023] Figure 1 A schematic diagram showing an example environment in which some embodiments of the present disclosure can be implemented is shown. As Figure 1As shown, the example environment 100 can include a processing terminal 101 that controls a robot arm 102 to take out a wafer in a cassette by establishing a connection with the robot arm 102, and then calculates an offset angle of the wafer based on a flat edge or a notch of the wafer by using an edge finder or an edge finding station, so as to control the robot arm 102 to perform pose correction on the wafer, and determines a wafer center position based on an identified outer contour of the wafer, and then places the wafer after the pose correction in a designated position of a stage 103 in a relatively horizontal posture in combination with the wafer center position. Here, the robot arm 102 can take out the wafer in the cassette by clamping or vacuum adsorption, and the wafer in the cassette can be divided into a standard wafer and a correction wafer used for subsequent process operations, and the correction wafer can be consistent with the type of the standard wafer, and of course the correction wafer of the embodiment of the present disclosure can also be a standard wafer, that is, the wafer in the cassette only contains a standard wafer, and is not limited thereto. It can be understood that the process of the processing terminal 101 for performing pose correction and center position determination on the wafer, and the process of controlling the robot arm 102 to place the wafer on the stage 103 all belong to the technical means known in the art, and will not be described in detail here.

[0024] In addition, the processing terminal 101 can also establish a connection with a low magnification lens 104 and a high magnification lens 105, so as to control the low magnification lens 104 to move above the wafer to collect a global image of the wafer after controlling the robot arm 102 to place the wafer on the stage 103, and the global image can be understood as an image containing the entire wafer surface, and the high magnification lens 105 is moved above the wafer to collect a template image corresponding to each target area based on at least four target areas in the global image. Here, the low magnification lens 104 and the high magnification lens 105 can be arranged on the same slide rail structure, and the processing terminal 101 can control the low magnification lens 104 to collect the global image by adjusting the height of the slide rail structure and the position of the low magnification lens 104 on the slide rail structure, and can also control the high magnification lens 105 to collect multiple template images by adjusting the height of the slide rail structure and the position of the high magnification lens 105 on the slide rail structure. It can be understood that the wafer will usually etch multiple template areas for positioning during the manufacturing process, and each target area in the above-mentioned global image contains any one template area, and the template image corresponding to each target area can be understood as containing the image of the template area in the corresponding target area, and the size parameter of each target area can be determined based on the magnification of the low magnification lens 104 (for example, when the magnification of the low magnification lens 104 is 5X, the size parameter of the target area can be represented as 6300*12800 pixels, so that each target area contains a complete template area), and the diagonal length of the template area in each target area is less than the shortest side of the target area.

[0025] In addition, after the processing terminal 101 acquires each template image captured by the high-magnification lens 105, the processing terminal 101 can control the mechanical arm 102 to retrieve the wafer to the cassette and control the mechanical arm 102 to place the wafer (or a correction wafer for subsequent process operations) at a designated position of the stage 103, and control the high-magnification lens to move above the wafer to capture a target image corresponding to each target region on the wafer. Here, each target image can include a corresponding target region, and each target region includes any one template region disposed on the wafer. It can be understood that the process of the processing terminal 101 controlling the mechanical arm 102 to place the wafer at the designated position of the stage 103 can be referred to above, and is a technical means well known in the art, which will not be described here.

[0026] In addition, after the processing terminal 101 acquires each target image captured by the high-magnification lens 105, the processing terminal 101 can determine the initial center position of each template image in the corresponding target image, then determine a search region in the corresponding target image based on the size parameter of each template image and the corresponding initial center position, and determine the target center position of each template image in the corresponding search region. Subsequently, the processing terminal 101 can determine the target affine transformation matrix based on the standard center position and the target center position corresponding to all template images, and determine the offset parameter of the wafer based on the target affine transformation matrix. It can be understood that the offset parameter of the wafer can include the rotation angle and the translation amount of the wafer in the horizontal plane, and the processing terminal 101 can feed back the rotation angle and the translation amount of the wafer in the horizontal plane to the PLC control system to drive the stage 103 to correct the position of the wafer by the PLC control system, and the single fine adjustment amount is not more than 20um (or can also be determined according to the stability, accuracy and wafer type of the mechanical arm, for example, when the stability of the mechanical arm is poor, it can also be set to 100um or more). Of course, the processing terminal 101 of the embodiments of the present disclosure can also directly drive the stage 103 to correct the position of the wafer based on the rotation angle and the translation amount of the wafer in the horizontal plane, which is not limited thereto.

[0027] In this way, the global image of the standard wafer can be acquired based on the low-magnification lens, and the template images corresponding to the plurality of target regions in the global image can be acquired based on the high-magnification lens, so as to jointly use the low-magnification lens and the high-magnification lens to ensure that the template images have both a field of view range and positioning accuracy. Secondly, the initial center position of each template image in the corresponding target image is determined to perform coarse positioning of the wafer to achieve the purpose of reducing the search range and adapting to errors. In addition, the target center position of each template image in the corresponding search region is determined to perform fine positioning of the wafer to solve the image angle offset problem, thereby improving the matching robustness under complex postures. Furthermore, the offset parameter of the correction wafer is determined based on the target affine transformation matrix, which not only realizes the micron-level precision positioning of the wafer, but also provides protection for subsequent process operations of the wafer.

[0028] It should be understood that the architecture and functionality in example environment 100 are described for illustrative purposes only and do not imply any limitation on the scope of this disclosure. Embodiments of this disclosure can also be applied to other environments with different architectures and / or functionalities.

[0029] Figure 2 A flowchart of a wafer positioning method according to some embodiments of the present disclosure is shown. Method 200 may be, for example, by... Figure 1 The processing terminal in the example environment shown executes. For example... Figure 2 As shown in block 202, method 200 can acquire a global image of the standard wafer based on a low-magnification lens, and acquire template images corresponding to at least four target regions in the global image based on a high-magnification lens. In some implementations, the processing terminal can control a robotic arm to remove the standard wafer from the cassette, and then use an edge finder or edge finding station to calculate the wafer offset angle based on the flat edge or notch of the standard wafer, so as to control the robotic arm to perform pose correction on the standard wafer, and determine the center position of the standard wafer based on the identified outer contour of the standard wafer, and then place the pose-corrected standard wafer in a relatively horizontal posture at a designated position on the stage, based on the center position of the standard wafer.

[0030] Subsequently, the processing terminal can control the low-magnification lens to move above the standard wafer to acquire a global image of the standard wafer. This global image can be understood as an image encompassing the entire surface of the standard wafer. At least four target regions are marked within this global image. Then, the high-magnification lens is switched to move above the standard wafer to acquire a template image corresponding to each target region based on its location. Here, each target region in the global image includes any template region set on the standard wafer. The template image corresponding to each target region can be understood as an image containing the template region within the corresponding target region. The size parameters of each target region can be determined based on the magnification of the low-magnification lens, and the diagonal length of the template region in each target region is less than the shortest side of the target region.

[0031] In some implementations, when the processing terminal acquires template images corresponding to at least four target regions in a global image based on a high-magnification lens, it can mark at least four target regions in the global image. Each target region includes any template region disposed on a standard wafer. In one example, four template regions located at different orientations can be identified in the global image based on an image recognition algorithm. Then, the center position of these four template regions is used as the center position of the corresponding target region. Combined with the target region size parameters determined by the magnification of the low-magnification lens (e.g., different magnifications have corresponding region size parameter correspondences), the corresponding four target regions are marked in the global image (or the template regions within each target region can also be marked simultaneously).

[0032] Referring to Figure 3 A global image diagram marked with a group of target regions and template regions according to some embodiments of the present disclosure is shown. As Figure 3 As shown, the global image 300 contains four target regions, each of which is marked by a rectangle frame with the same size parameter, and each of which contains any one template region disposed on the standard wafer, and each of which can also mark the corresponding template region by a rectangle frame with the same size parameter.

[0033] In addition, referring to Figure 4 A global image diagram marked with a group of target regions and template regions according to some embodiments of the present disclosure is shown. As Figure 4 As shown, the target regions in the global image 400 can be marked by larger rectangle frames, and the corresponding template regions can be marked by smaller rectangle frames. It can be seen that the template regions are in the target regions, and the template image mentioned in the embodiments of the present disclosure can be understood as an image containing the template regions, and the target image mentioned can be understood as an image containing the target regions.

[0034] Of course, the embodiments of the present disclosure can also be marked by the operator on at least four target regions in the global image and the template regions in each target region, and are not limited thereto.

[0035] After that, the processing terminal can acquire the template images corresponding to each template region in the global image based on the high magnification lens. In an example, the high magnification lens can be switched to move above the standard wafer, and the template images corresponding to the corresponding template regions can be acquired based on the positions of each target region, so that each template image contains the corresponding complete template region. In addition, after acquiring the template images corresponding to each template region, the processing terminal can also determine the physical coordinates of the center of each template image in the plane rectangular coordinate system established based on the stage based on the center pixel coordinates of each template image and the plane rectangular coordinate system established based on the stage, that is, the standard center position of each template image. Here, the plane rectangular coordinate system established based on the stage can be understood as a plane rectangular coordinate system with the center of the stage as the origin, the horizontal right direction of the center of the stage as the horizontal axis direction, and the vertical upward direction of the center of the stage as the vertical axis direction. The processing terminal can determine the conversion matrix between the pixel coordinates on the template image collected by the high magnification lens and the physical coordinates in the plane rectangular coordinate system through the nine-point calibration algorithm, and calculate the standard center position of each template image based on the conversion matrix and the center pixel coordinates of each template image. It can be understood that the process of determining the conversion matrix through the nine-point calibration algorithm belongs to the technical means well known in the art. Of course, the embodiments of the present disclosure can also use other technical means well known in the art to determine the standard center position of each template image, but more details are not described here.

[0036] In addition, after obtaining the template images corresponding to the template regions, the processing terminal can determine the pixel equivalent of the corresponding template image based on the size parameters of the template image and the resolution of the high-magnification lens at the current magnification (the high-magnification lens has a corresponding resolution at different magnifications). Here, the size parameters of the template image can include width and height. The pixel equivalent corresponding to the horizontal direction of the template image can be determined by ratio calculation on the width of the template image and the number of pixels corresponding to the horizontal direction in the resolution of the high-magnification lens at the current magnification. The pixel equivalent corresponding to the vertical direction of the template image can also be determined by ratio calculation on the height of the template image and the number of pixels corresponding to the vertical direction in the resolution of the high-magnification lens at the current magnification, and is not limited thereto.

[0037] At block 204, the method 200 can obtain target images corresponding to the target regions on the correction wafer based on the high-magnification lens, and determine the initial center positions of the template images in the corresponding target images. In some embodiments, the processing terminal can control the mechanical arm to retrieve the standard wafer into the cassette, and then control the mechanical arm to take out the correction wafer (or the standard wafer) for subsequent process operations from the cassette and place it at a designated position of the stage. The high-magnification lens is controlled to move above the standard wafer, and the target images corresponding to the target regions are acquired based on the positions and size parameters of the target regions, so that each target image contains the corresponding complete target region and the template region within the complete target region. Here, the position of each target region can be understood as the physical coordinates of the center of each template image in the planar rectangular coordinate system, so as to control the high-magnification lens to quickly find each target region above the correction wafer, thereby improving the acquisition efficiency of each target image. It can be understood that the process of the processing terminal controlling the mechanical arm to place the correction wafer at a designated position of the stage can be referred to the above, and is a technical means well known in the art, which will not be described in detail here.

[0038] It should be noted that, since the correction wafer and the standard wafer are the same type of wafer (or the correction wafer is the standard wafer), the template regions contained in each target image are exactly the same as the template regions contained in the corresponding template image, so as to ensure the accuracy of the offset parameters of the subsequent correction wafer.

[0039] In some embodiments, when determining the initial center position of each template image in the corresponding target image, the processing terminal can determine whether the pixel equivalent of each template image is consistent with the pixel equivalent of the corresponding target image based on the pixel equivalent of each template image and the pixel equivalent of the corresponding target image. Here, the pixel equivalent determination process of the target image can refer to the above, for example, by calculating the ratio of the number of pixels corresponding to the horizontal direction in the width of the target image and the resolution of the high magnification lens at the corresponding magnification when the target image is acquired, to determine the pixel equivalent corresponding to the horizontal direction of the target image; and also by calculating the ratio of the number of pixels corresponding to the vertical direction in the height of the target image and the resolution of the high magnification lens at the corresponding magnification when the target image is acquired, to determine the pixel equivalent corresponding to the vertical direction of the target image, without being limited thereto.

[0040] It can be understood that when the pixel equivalent corresponding to the horizontal direction of each template image is inconsistent with the pixel equivalent corresponding to the horizontal direction of the corresponding target image, or the pixel equivalent corresponding to the vertical direction of each template image is inconsistent with the pixel equivalent corresponding to the vertical direction of the corresponding target image, it indicates that the pixel equivalent of each template image is inconsistent with the pixel equivalent of the corresponding target image; when the pixel equivalent corresponding to the horizontal direction of each template image is consistent with the pixel equivalent corresponding to the horizontal direction of the corresponding target image, and the pixel equivalent corresponding to the vertical direction is consistent with the pixel equivalent corresponding to the vertical direction of the corresponding target image, it indicates that the pixel equivalent of each template image is consistent with the pixel equivalent of the corresponding target image.

[0041] Subsequently, the processing terminal can perform scaling processing on the corresponding template image based on the pixel equivalent of each target image in response to determining that the pixel equivalent of each template image is inconsistent with the pixel equivalent of the corresponding target image, so that the to-be-matched target (i.e., the template region) in each template image and the corresponding target image after scaling processing remains consistent in the size parameter. In an example, taking the pixel equivalent corresponding to the horizontal direction of each template image being less than the pixel equivalent corresponding to the horizontal direction of the corresponding target image, and the pixel equivalent corresponding to the vertical direction being less than the pixel equivalent corresponding to the vertical direction of the corresponding target image as an example, the corresponding template image can be enlarged based on the pixel equivalent corresponding to the horizontal direction and the vertical direction of the target image, so that the pixel equivalent corresponding to the horizontal direction of each template image after enlargement processing is consistent with the pixel equivalent corresponding to the horizontal direction of the corresponding target image, and the pixel equivalent corresponding to the vertical direction is consistent with the pixel equivalent corresponding to the vertical direction of the corresponding target image.

[0042] After that, the processing terminal can perform down-sampling processing on each template image after the scaling processing and the corresponding target image, and process each template image after the down-sampling processing and the corresponding target image based on a template matching algorithm to determine the initial center position of each template image in the corresponding target image. It can be understood that, since the resolution of each template image and each target image is high, if each template image and each target image is directly processed, it is easy to cause excessive resource consumption, therefore, the down-sampling processing can be performed on each template image after the scaling processing and the corresponding target image to determine the approximate position of each template image in the corresponding target image in the wafer coarse positioning stage. Here, the down-sampling processing on each template image after the scaling processing and the corresponding target image can be understood as fusion processing of pixels in each template image and each target image based on a linear interpolation algorithm, and the processing process is a technical means known in the art, which will not be described here.

[0043] In addition, processing each template image after the down-sampling processing and the corresponding target image based on the template matching algorithm can be understood as performing multiple sliding processing on each template image after the down-sampling processing in the corresponding target image in the order from left to right and from top to bottom, then calculating the matching degree between each template image and the corresponding target image corresponding to each position based on the position of each template image center in the corresponding target image after each sliding processing (i.e. the pixel coordinates of each template image center in the corresponding target image), to count the matching degrees corresponding to multiple positions by constructing a matching degree matrix, and determine the position corresponding to the maximum matching degree as the initial center position of each template image in the corresponding target image. Here, calculating the matching degree between each template image and the corresponding target image corresponding to each position can be understood as performing normalization processing on each template image and the corresponding target image corresponding to each position respectively, then identifying the overlapping area between each template image after the normalization processing and the corresponding target image, and calculating the matching degree based on the multiple position pixel values of each template image in the overlapping area after the normalization processing and the multiple corresponding position pixel values of the corresponding target image in the overlapping area, and the processing process is a technical means known in the art, which will not be described here.

[0044] At block 206, the method 200 can determine a search region in the corresponding target image based on the size parameter of the template image and the corresponding initial center position, and determine a target center position of the template image in the corresponding search region. In some embodiments, when determining the search region in the corresponding target image based on the size parameter of the template image and the corresponding initial center position, the processing terminal can determine the size parameter of the corresponding search region based on the size parameter of the template image and a preset expansion size parameter. It can be understood that the size parameter of the template image includes a width and a height, the preset expansion size parameter includes a preset expansion width and a preset expansion height, and the size parameter of the search region corresponding to the template image includes a width and a height of the search region. In an example, the width of the search region corresponding to the template image can be a sum of the width of the template image and the preset expansion width, and the height of the search region corresponding to the template image can be a sum of the height of the template image and the preset expansion height. In this way, the amount of calculation can be effectively reduced, and the wafer positioning efficiency can be improved.

[0045] Subsequently, the processing terminal can determine the search region in the corresponding target image based on the initial center position corresponding to the template image and the size parameter of the corresponding search region. In an example, the initial center position corresponding to the template image can be identified in the target image as the center position of the search region, and the search region can be determined in the target image based on the size parameter and the center position of the search region, so that the distance between each width side of the search region and the center position is half of the height in the size parameter, and the straight-line distance between each height side of the search region and the center position is half of the width in the size parameter.

[0046] In some embodiments, when determining the target center position of the template image in the corresponding search region, the processing terminal can perform rotation processing on the template image based on a preset rotation angle to obtain at least two rotated images corresponding to the template image. Here, the preset rotation angle can be understood as a plurality of rotation angles determined based on an angle range of -10 degrees to 10 degrees and a step size of 0.5 degrees. By keeping the center position of the template image unchanged, the template image is rotated according to each rotation angle to obtain a rotated image of the template image at each rotation angle.

[0047] Afterwards, the processing terminal can determine a search image of the corresponding search region in each target image, and process each rotated image corresponding to each template image and the search image based on the template matching algorithm to obtain the center pixel position of each template image in the corresponding search region. In an example, the search region in each target image can be cropped to obtain the search image of the corresponding search region, and when each rotated image corresponding to each template image and the search image are processed based on the template matching algorithm, each rotated image corresponding to each template image is slid on the corresponding search image multiple times in the order from left to right and from top to bottom; then, based on the position of each rotated image center on the corresponding search image after each sliding processing (i.e. the pixel coordinates of each rotated image center on the corresponding search image), the matching degree between each rotated image corresponding to each position and the corresponding search image is calculated to count the matching degrees corresponding to multiple positions by constructing a matching degree matrix; then, after obtaining the matching degree matrix between each rotated image corresponding to each template image and the corresponding search image, the position corresponding to the maximum matching degree in all matching degree matrices is determined as the center pixel position of each template image in the corresponding search region. Here, calculating the matching degree between each rotated image corresponding to each position and the corresponding search image can be understood as normalizing each rotated image corresponding to each position and the corresponding search image, then identifying the overlapping region between each normalized rotated image and the corresponding search image, and calculating the matching degree based on the multiple position pixel values of each normalized rotated image in the overlapping region and the multiple corresponding position pixel values of the corresponding search image in the overlapping region, which is a technical means known in the art and will not be described here.

[0048] Of course, the embodiments of the present disclosure can also not need to rotate each template image based on the preset rotation angle, i.e. the preset rotation angle can also be set to 0. In an example, the processing terminal can also determine the search image of the corresponding search region in each target image, and directly process each template image and the search image based on the template matching algorithm to obtain the center pixel position of each template image in the corresponding search region. Here, the process of determining the center pixel position of each template image in the corresponding search region can refer to the above, and will not be described here.

[0049] Afterwards, the processing terminal can convert the center pixel position corresponding to the respective template image based on the pixel equivalent and the vertex position of each target image to obtain the target center position of each template image in the corresponding search area, i.e. the pixel position of the center of each template image in the corresponding search area, the physical coordinates in the plane rectangular coordinate system corresponding to the stage. Here, the vertex position of each target image can be understood as the physical coordinates of the top-left vertex (of course, it can also be other vertices, not limited to this) of each target image in the plane rectangular coordinate system corresponding to the stage, which can be determined based on the physical coordinates of the center of the corresponding target image in the plane rectangular coordinate system corresponding to the stage, the pixel size and the pixel equivalent of the corresponding target image, for example, taking that the vertex position of each target image is represented as (left_physical, top_physical), the physical coordinates of the center of the corresponding target image in the plane rectangular coordinate system corresponding to the stage is represented as (x_center_physical, y_center_physical), the pixel size of the corresponding target image includes the pixel width and the pixel height, and the pixel equivalent of the corresponding target image includes the pixel equivalent corresponding to the horizontal direction and the pixel equivalent corresponding to the vertical direction as an example, the vertex position of each target image can be determined by the expression shown as follows:

[0050] left_physical = x_center_physical - pixel width * 0.5 * pixel equivalent corresponding to the horizontal direction

[0051] top_physical = y_center_physical + pixel height * 0.5 * pixel equivalent corresponding to the vertical direction

[0052] It can be understood that the physical coordinates of the center of each target image in the plane rectangular coordinate system corresponding to the stage can be determined when the target image corresponding to each target region on the corrected wafer is obtained based on the high magnification lens, of course, it can also be obtained by using the technical means known in the art, but more details are not described here.

[0053] In an example, taking that the pixel equivalent of each target image is represented as including the pixel equivalent corresponding to the horizontal direction and the pixel equivalent corresponding to the vertical direction, the vertex position of each target image is represented as (left_physical, top_physical), the center pixel position corresponding to each template image is represented as (u, v), and the target center position of each template image in the corresponding search area is represented as (x, y) as an example, the target center position of each template image in the corresponding search area can be determined by the expression shown as follows:

[0054] x = left_physical + u * pixel equivalent corresponding to the horizontal direction

[0055] y = top physical - v * pixel equivalent in vertical direction

[0056] At block 208, the method 200 can determine a target affine transformation matrix based on the standard center positions and the target center positions corresponding to all the template images, and determine the offset parameters of the corrected wafer based on the target affine transformation matrix. In some embodiments, when determining the target affine transformation matrix based on the standard center positions and the target center positions corresponding to all the template images, the processing terminal can determine at least two calculation position sets each having the standard center positions and the target center positions corresponding to at least three template images and the verification position sets corresponding to the calculation position sets each having the standard center position and the target center position corresponding to one template image. In an example, when the number of all the template images is four, four calculation position sets each including the standard center positions and the target center positions corresponding to any three template images and the verification position sets corresponding to the calculation position sets each including the standard center position and the target center position corresponding to the remaining one template image can be determined by combination processing of all the template images.

[0057] Subsequently, the processing terminal can construct the initial affine transformation matrix corresponding to each calculation position set based on the calculation position set, and determine the deviation value corresponding to each calculation position set based on the verification position set corresponding to the calculation position set and the initial affine transformation matrix. In an example, the standard center position and the target center position corresponding to each template image in each calculation position set can be substituted into a preset matrix parameter calculation expression, the matrix parameters to be solved in the affine transformation matrix in the preset matrix parameter calculation expression can be calculated by the least square method, and the affine transformation matrix with the substituted matrix parameters can be taken as the initial affine transformation matrix corresponding to each calculation position set. Here, the preset matrix parameter calculation expression can refer to the expression shown as follows:

[0058]

[0059] In the above expression, (x, y) can be the target center position corresponding to the template image, (x', y') can be the standard center position corresponding to the template image, and a, b, c, d, e, and f can be the matrix parameters to be solved in the affine transformation matrix.

[0060] ​​​​After obtaining the initial affine transformation matrix corresponding to each set of calculated positions, the standard center position in the verification position set and the corresponding initial affine transformation matrix corresponding to each set of calculated positions can be substituted into the above-mentioned preset matrix parameter calculation expression to obtain an actual center position, and the deviation value between the actual center position and the target center position in the verification position set is calculated, and the error value is taken as the deviation value corresponding to the corresponding set of calculated positions. Here, the deviation value between the actual center position and the target center position in the verification position set can be calculated by the expression as follows:

[0061] Diff = max(| x - x’|,| y - y’|)

[0062] In the above expression, Diff can be the deviation value between the actual center position and the target center position in the verification position set, max( ) can be the maximum value, (x, y) can be the target center position in the verification position set, and (x', y') can be the actual center position.

[0063] It can be understood that when the deviation value corresponding to a set of calculated positions exceeds the preset deviation threshold, it indicates that the initial affine transformation matrix corresponding to the set of calculated positions is invalid; when the deviation value corresponding to a set of calculated positions does not exceed the preset deviation threshold, it indicates that the initial affine transformation matrix corresponding to the set of calculated positions is valid.

[0064] After that, the processing terminal can determine the mean value calculation result of all initial affine transformation matrices as the target affine transformation matrix in response to determining that the deviation value corresponding to each set of calculated positions does not exceed the preset deviation threshold. It can be understood that the matrix parameters of each position in the target affine transformation matrix can be the mean value calculation result of the corresponding position matrix parameters in all initial affine transformation matrices. In addition, the embodiments of the present disclosure can directly take the initial affine transformation matrix corresponding to the set of calculated positions as the target affine transformation matrix when it is determined that only the deviation value corresponding to one set of calculated positions does not exceed the preset deviation threshold.

[0065] In some embodiments, when the processing terminal determines the offset parameter of the correction wafer based on the target affine transformation matrix, the target rotation angle can be determined based on the matrix parameters in the preset first position in the target affine transformation matrix. Here, the preset first position can be understood as the first row and the first column in the target affine transformation matrix. In an example, the target rotation angle is calculated by substituting the matrix parameters in the preset first position in the target affine transformation matrix into the expression as follows:

[0066] θ = arctan2 (d, a)

[0067] In the above formula, θ can be a target rotation angle, a and d can be matrix parameters in a preset first position in a target affine transformation matrix (a can be a matrix parameter in the first row and the first column in the target affine transformation matrix, and d can be a matrix parameter in the second row and the first column in the target affine transformation matrix).

[0068] Afterwards, the processing terminal can further determine a translation based on matrix parameters in a preset second position in the target affine transformation matrix, and determine the target rotation angle and the translation as the offset parameters of the correction wafer. Here, the preset second position can be understood as the first row and the third column and the second row and the third column in the target affine transformation matrix, and the translation can be understood as a horizontal direction offset and a vertical direction translation, the horizontal direction offset being the matrix parameter in the first row and the third column in the target affine transformation matrix, and the vertical direction translation being the matrix parameter in the second row and the third column in the target affine transformation matrix.

[0069] It can be understood that after the offset parameters of the correction wafer are determined, the processing terminal can further feed back the offset parameters of the correction wafer to the PLC control system, so that the PLC control system drives the stage to realize position correction of the correction wafer, so as to ensure that the position-corrected correction wafer is consistent with the standard wafer in position on the stage, and the single fine adjustment amount is not more than 20 um (or can also be determined according to the mechanical arm stability, precision and wafer type, for example, when the mechanical arm stability is poor, it can also be set to 100 um or more). Of course, the processing terminal of the embodiment of the present disclosure can also directly drive the stage to realize position correction of the correction wafer based on the offset parameters of the correction wafer, which is not limited thereto.

[0070] Of course, after the position correction of the correction wafer is processed based on the offset parameters of the correction wafer, the embodiment of the present disclosure can also perform homing verification on the position-corrected correction wafer, for example, the high-magnification lens is controlled again to collect target images corresponding to each target region on the position-corrected correction wafer, and the deviation values corresponding to each calculation position set are calculated again by referring to the above steps. It can be understood that when the deviation values corresponding to each calculation position set calculated again all do not exceed the preset deviation threshold, it indicates that the correction wafer has completed position correction; when the deviation values corresponding to one or more calculation position sets calculated again still exceed the preset deviation threshold, it indicates that the correction wafer has not completed position correction, and then the offset parameters of the correction wafer can be calculated again by referring to the execution of the above steps, until the correction wafer completes position correction.

[0071] Please refer to Figure 5 A wafer positioning effect schematic diagram according to some embodiments of the present disclosure is shown. As shown in FIG. 6, the wafer positioning effect schematic diagram is used to illustrate the wafer positioning effect of the embodiment of the present disclosure. Figure 5The superimposed image between the standard wafer image and the corrected wafer image without position correction is shown in 5A, and it can be seen that ghosting occurs in the superimposed image, i.e., the positions of the corrected wafer and the standard wafer on the stage are inconsistent. The superimposed image between the standard wafer image and the corrected wafer image after position correction is shown in 5B, and it can be seen that no ghosting occurs in the superimposed image, i.e., the positions of the corrected wafer and the standard wafer on the stage are consistent.

[0072] Figure 6 A block diagram of a wafer positioning apparatus according to some embodiments of the present disclosure is shown. Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts between each of the embodiments can be referred to each other. Each of the embodiments focuses on the differences from other embodiments. In particular, for the apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiments. As shown in the drawings, Figure 6 As shown, the wafer positioning apparatus 600 includes an image acquisition module 602 configured to acquire a global image of a standard wafer based on a low magnification lens, and acquire template images corresponding to at least four target regions in the global image based on a high magnification lens, each template image having a corresponding standard center position. The wafer positioning apparatus 600 further includes a position determination module 604 configured to acquire target images corresponding to each target region on a corrected wafer based on the high magnification lens, and determine initial center positions of each template image in the corresponding target image. The wafer positioning apparatus 600 further includes a position calculation module 606 configured to determine search regions in the corresponding target image based on size parameters of each template image and the corresponding initial center positions, and determine target center positions of each template image in the corresponding search region. In addition, the wafer positioning apparatus 600 further includes a parameter generation module 608 configured to determine a target affine transformation matrix based on the standard center positions and the target center positions corresponding to all template images, and determine offset parameters of the corrected wafer based on the target affine transformation matrix.

[0073] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this specification are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., Digital Versatile Discs (DVDs)), or semiconductor media (e.g., Solid State Disks (SSDs)).

[0074] Figure 7 Block diagrams of electronic devices that can implement various embodiments of the present disclosure are shown. For example... Figure 7 As shown, the electronic device 700 includes a processor 701, which can perform various appropriate actions and processes based on computer program instructions loaded into random access memory (RAM) 703 according to computer program instructions stored in read-only memory (ROM) 702. The RAM 703 may also store various programs and data required for the operation of the electronic device 700. The processor 701, ROM 702, and RAM 703 are interconnected via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0075] The various processes and procedures described above, such as method 200, can be executed by processor 701. For example, in some embodiments, method 200 may be implemented as a software program tangibly contained in a machine-readable medium. In some embodiments, part or all of the software program may be loaded into and / or installed onto electronic device 700 via ROM 702. When the software program is loaded into RAM 703 and executed by processor 701, one or more actions of method 200 described above may be performed.

[0076] The functionality described herein above can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Program- specific Integrated Circuits (ASICs), Program- specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0077] Program code for carrying out methods of the present disclosure can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the program code, when executed by the processor or controller, produces a means for implementing the functions / operations specified in the flowchart and / or block diagram block or blocks. The program code can be retrieved from the machine or a remote storage medium, and executed by the processor or controller, or downloaded from a network, e.g., the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A remote server can store, e.g., program code in its memory for downloading to one or more corresponding client computers. A remote server that receives something from, e.g., a client computer, can forward that something to another server, such as sending a program code from a server to a

[0078] The present disclosure can be a method, apparatus, system, and / or program product. Program products can include machine-readable storage media with machine- readable program instructions stored therein to perform various aspects of the present disclosure. The machine-readable program instructions described herein can be downloaded to various computing / processing devices from a machine-readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter of each computing / processing device receives machine-readable program instructions from the network and forwards the machine-readable program instructions to a storage medium within the respective computing / processing device for execution by a processor.

[0079] Machine program instructions for performing operations of the present disclosure can be assembly instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The machine readable program instructions may, in entirety, be executed on the user's computer, executed partially on the user's computer, executed as a standalone software package, executed partially on the user's computer and partially on a remote computer, or executed entirely on a remote computer or server. In situations

[0080] In the context of the present disclosure, a machine readable medium can be a tangible medium that can contain or store program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium can be a machine readable signal medium or a machine readable storage medium. Machine readable medium can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of machine readable storage medium would include one or more lines of electrical wire, portable computer diskette, hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination of the foregoing. Further, while operations are depicted in a particular order, this should not be understood as requiring such order or sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Likewise, while specific implementations are discussed herein, these should not be construed as limiting the scope of the present disclosure. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination.

[0081] Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A wafer positioning method, characterized in that, include: A global image of a standard wafer is acquired using a low-magnification lens, and template images corresponding to at least four target regions in the global image are acquired using a high-magnification lens. Each template image has a corresponding standard center position. Based on the high-magnification lens, target images corresponding to each target region on the calibration wafer are acquired, and the initial center position of each template image in the corresponding target image is determined; Based on the size parameters of each template image and the corresponding initial center position, a search area is determined in the corresponding target image, and the target center position of each template image in the corresponding search area is determined. as well as Based on the standard center position and the target center position corresponding to all the template images, the target affine transformation matrix is ​​determined, and the offset parameter of the correction wafer is determined based on the target affine transformation matrix.

2. The method according to claim 1, characterized in that, The step of acquiring template images corresponding to at least four target regions in the global image based on a high-magnification lens includes: At least four target regions are marked in the global image, each target region having a corresponding template region; and The template images corresponding to each template region in the global image are obtained using a high-magnification lens.

3. The method according to claim 1, characterized in that, Determining the initial center position of each template image in the corresponding target image includes: Based on the pixel equivalent of each template image and the pixel equivalent of the corresponding target image, determine whether the pixel equivalent of each template image is consistent with the pixel equivalent of the corresponding target image; In response to determining that the pixel equivalent of each of the template images is inconsistent with the pixel equivalent of the corresponding target image, the corresponding template image is scaled based on the pixel equivalent of each of the target images; and The scaled template images and corresponding target images are downsampled, and the downsampled template images and corresponding target images are processed based on a template matching algorithm to determine the initial center position of each template image in the corresponding target image.

4. The method according to claim 1, characterized in that, The step of determining the search region in the corresponding target image based on the size parameters of each template image and the corresponding initial center position includes: Based on the size parameters of each template image and the preset extended size parameters, the size parameters of the corresponding search area are determined; and Based on the initial center position corresponding to each template image and the size parameters of the corresponding search region, a search region is determined in the corresponding target image.

5. The method according to claim 4, characterized in that, Determining the target center position of each template image in the corresponding search area includes: The template images are rotated based on a preset rotation angle to obtain at least two rotated images corresponding to each template image; In each of the target images, a search image corresponding to the search region is determined, and based on a template matching algorithm, each of the rotated images corresponding to each template image and the search image are processed to obtain the center pixel position of each template image in the corresponding search region; and Based on the pixel equivalent and vertex position of each target image, the center pixel position corresponding to the template image is transformed to obtain the target center position of each template image in the corresponding search area.

6. The method according to any one of claims 1-5, characterized in that, The step of determining the target affine transformation matrix based on the standard center position and the target center position corresponding to all the template images includes: Based on the standard center positions corresponding to all the template images, at least two sets of calculated positions and a set of verified positions corresponding to each set of calculated positions are determined. Each set of calculated positions has at least three standard center positions and target center positions corresponding to the template images. Each set of verified positions has one standard center position and one target center position corresponding to the template image. Construct corresponding initial affine transformation matrices based on each set of computational locations, and determine corresponding deviation values ​​based on the verification location set corresponding to each set of computational locations and the initial affine transformation matrices. Determine whether the deviation value corresponding to each of the calculated location sets exceeds a preset deviation threshold; and In response to determining that the deviation value corresponding to each of the calculated position sets does not exceed the preset deviation threshold, the mean calculation result of all the initial affine transformation matrices is determined as the target affine transformation matrix.

7. The method according to claim 6, characterized in that, Determining the offset parameters of the calibration wafer based on the target affine transformation matrix includes: The target rotation angle is determined based on the matrix parameters at a preset first position in the target affine transformation matrix; and The translation amount is determined based on the matrix parameters at the preset second position in the target affine transformation matrix, and the target rotation angle and the translation amount are determined as the offset parameters of the correction wafer.

8. A wafer positioning device, characterized in that, include: The image acquisition module is configured to acquire a global image of a standard wafer based on a low-magnification lens, and to acquire template images corresponding to at least four target regions in the global image based on a high-magnification lens, each template image having a corresponding standard center position; The position determination module is configured to acquire target images corresponding to each target region on the calibration wafer based on the high-magnification lens, and determine the initial center position of each template image in the corresponding target image; The position calculation module is configured to determine a search area in the corresponding target image based on the size parameters of each template image and the corresponding initial center position, and to determine the target center position of each template image in the corresponding search area; as well as The parameter generation module is configured to determine the target affine transformation matrix based on the standard center position and the target center position corresponding to all the template images, and to determine the offset parameters of the calibration wafer based on the target affine transformation matrix.

9. A computer-readable storage medium having a computer program stored thereon, the computer-readable storage medium storing instructions that, when executed on a computer or processor, cause the computer or processor to perform the steps of the method as claimed in any one of claims 1-7.

10. An electronic device, characterized in that, include: One or more processors, and A memory associated with the one or more processors, the memory being used to store program instructions that, when read and executed by the one or more processors, perform the steps of the method according to any one of claims 1-7.

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