A wafer center positioning method, device, equipment and medium

Abstract

The present invention discloses a wafer center positioning method, device, equipment and medium. The method comprises: acquiring a wafer image; acquiring position information of at least three points of interest in the wafer image in a rectangular coordinate system; fitting a first reference circle using the at least three points of interest, and calculating a first center position of the first reference circle using the position information of the at least three points of interest; extracting edge curvature information of the wafer image; obtaining a second reference circle by arc fitting according to the edge curvature information, and calculating a second center position of the second reference circle; performing centroid calculation on the first center position and the second center position to obtain the wafer center. The method is used to accurately locate the wafer center.

Description

Technical Field

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

[0002] At present, the angle correction and center position determination of the wafer are important links in the integrated circuit manufacturing process. The current algorithm for the angle correction and center position determination of the wafer is mainly to collect the local edge image of the wafer, record the physical coordinates, and then select the edge point on the image, and locate the center of the circle through three points on non-straight lines. However, the edge points manually selected by this method may have errors. Under the requirement of high-precision center positioning, the calculation results will have errors. Based on the above background, how to improve the detection accuracy of the wafer center has become a technical problem currently faced. Summary of the invention

[0003] The embodiments of the present invention provide a wafer center positioning method, device, equipment and medium, which are used to improve the problem of low accuracy of wafer center positioning results.

[0004] In a first aspect, the present invention provides a wafer center positioning method, comprising: acquiring a wafer image; acquiring position information of at least three points of interest in the wafer image in a rectangular coordinate system; fitting a first reference circle using the at least three points of interest, and calculating a first center position of the first reference circle using the position information of the at least three points of interest; extracting edge curvature information of the wafer image; obtaining a second reference circle by arc fitting based on the edge curvature information, and calculating a second center position of the second reference circle; performing centroid calculation on the first center position and the second center position to obtain the wafer center.

[0005] The beneficial effect of the wafer center positioning method provided by the present invention is that based on the first circle center position calculated by the mark point interest point, the coordinates of the image and the motion system in the current state of the device are also obtained, and the arc of the image is calculated by the visual algorithm for circle fitting to obtain the second circle center position. The first circle center position obtained by fitting and the second circle center position obtained by calculating the interest point are combined, and the centroid of these circle center points is calculated, and the centroid is used as the final wafer center, which helps to improve the accuracy of the wafer center positioning result.

[0006] In a possible embodiment, extracting the edge curvature information of the wafer image includes: extracting the edge curvature information of the wafer image by using an image vision algorithm.

[0007] In another possible embodiment, the acquisition of the wafer image includes: rotating the wafer with a turntable and acquiring the wafer image frame by frame along the outer edge of the wafer; extracting the edge curvature information of the wafer image through an image vision algorithm, including: processing the acquired wafer image frame by frame and extracting the edge feature points of the wafer image; fitting an arc according to the edge feature points to obtain the edge curvature information of the wafer image. This method helps to accurately extract the feature points of the edge of the wafer image, thereby obtaining the edge curvature information of the wafer image.

[0008] In other possible embodiments, before processing the collected wafer images frame by frame and extracting edge feature points of the wafer images, the method further includes: performing Gaussian filtering on the wafer images.

[0009] In yet another possible embodiment, the three interest points are selected at unequal intervals.

[0010] In a second aspect, an embodiment of the present invention further provides a wafer center positioning device, which includes modules / units for executing any possible design method of the first aspect. These modules / units can be implemented by hardware, or by hardware executing corresponding software implementations.

[0011] In a third aspect, an embodiment of the present invention provides an electronic device, including a processor and a memory, wherein the memory is used to store one or more computer programs; when the one or more computer programs stored in the memory are executed by the processor, the electronic device can implement any possible design method of the second aspect.

[0012] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium includes a computer program. When the computer program runs on an electronic device, the electronic device executes any possible design method of any of the above aspects.

[0013] In a fifth aspect, an embodiment of the present invention further provides a method comprising a computer program product, which, when executed on a terminal, enables the electronic device to execute any possible design of any of the above aspects.

[0014] For the beneficial effects of the second to fifth aspects, reference may be made to the description of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A schematic diagram of the structure of a wafer center positioning device provided by an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of a wafer center positioning method provided by an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of selecting interest points on a wafer image provided by an embodiment of the present invention;

[0019] Figure 4 A schematic structural diagram of a wafer center positioning device provided by an embodiment of the present invention;

[0020] Figure 5 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] To make the content of the present invention more clear and understandable, the content of the present invention is further described below in conjunction with the accompanying drawings of the specification. Of course, the present invention is not limited to this specific embodiment, and general replacements known to those skilled in the art are also covered within the protection scope of the present invention.

[0022] It should be noted that in the following specific embodiments, when describing the embodiments of the present invention in detail, in order to clearly represent the structure of the present invention for the convenience of explanation, the structures in the accompanying drawings are not drawn according to general proportions, and are partially enlarged, deformed and simplified. Therefore, it should be avoided to understand this as a limitation of the present invention.

[0023] See also Figure 1 The present invention provides a possible wafer center positioning device, which includes a carrier 1, and the carrier 1 is used to carry the wafer to be tested. In addition, the wafer center positioning device also includes an image sensor 2, and the image sensor 2 is used to collect the edge image of the wafer to be tested. The wafer center positioning device also includes a driving device, and the driving device 3 is used to drive the carrier to rotate.

[0024] Figure 2 FIG. 1 is a schematic flow chart of a wafer center positioning method provided by an embodiment of the present invention. Figure 2 As shown, the method can be performed by an electronic device, and the method includes the following steps:

[0025] S201, acquiring a wafer image.

[0026] The turntable rotates the wafer and captures wafer images frame by frame along the outer edge of the wafer;

[0027] S202, obtaining position information of at least three points of interest in the wafer image in a rectangular coordinate system.

[0028] For example, refer to Figure 3 As shown, firstly, the local edge image of the wafer is collected and the physical coordinates are recorded, and then three points of interest are manually selected on the local edge image of the wafer, and the center of the circle is located by the three points of interest on non-straight lines. The selection intervals of the three points of interest are not equal.

[0029] S203: A first reference circle is obtained by fitting the at least three interest points, and a first center position of the first reference circle is calculated by using the position information of the at least three interest points.

[0030] S204, extracting edge curvature information of the wafer image; obtaining a second reference circle by arc fitting according to the edge curvature information, and calculating a second center position of the second reference circle.

[0031] Optionally, before processing the collected wafer images frame by frame and extracting edge feature points of the wafer images, the method further includes: performing Gaussian filtering on the wafer images.

[0032] In this step, the collected wafer images are processed frame by frame and edge feature points of the wafer images are extracted; arcs are fitted according to the edge feature points to obtain edge curvature information of the wafer images.

[0033] S205, performing centroid calculation on the first circle center position and the second circle center position to obtain a wafer center.

[0034] The wafer center obtained in the embodiment of the present invention is mainly used for wafer positioning after loading of semiconductor equipment.

[0035] It can be seen that this embodiment is based on the first circle center position calculated by the mark point interest point, and also obtains the coordinates of the image and motion system in the current state of the device, and calculates the arc of the image through the visual algorithm for circle fitting, so as to obtain the second circle center position. The first circle center position calculated by the interest point and the second circle center position obtained by arc fitting are combined, and the centroid of these circle center points is calculated. This centroid is used as the final wafer center, which helps to improve the accuracy of the wafer center positioning result.

[0036] In summary, compared with the prior art, the wafer center positioning method proposed in the embodiment of the present invention extracts the curvature information of the wafer edge by combining it with the image of the selected edge points, obtains the center of the circle by fitting the arc, and performs centroid calculation on the obtained several center positions to obtain the final wafer center, thereby avoiding the errors caused by traditional manually selected edge points, and the calculation results will be more accurate.

[0037] In some embodiments of the present application, the present invention also discloses a wafer center positioning device, such as Figure 4 As shown, the device is used to implement the methods described in the above method embodiments, which includes: an acquisition unit 401, used to acquire a wafer image; and to acquire the position information of at least three points of interest in the wafer image in a rectangular coordinate system; a processing unit 402, used to fit a first reference circle using the at least three points of interest, and to calculate the first center position of the first reference circle using the position information of the at least three points of interest. An extraction unit 403 is used to extract the edge curvature information of the wafer image. The processing unit 402 is also used to obtain a second reference circle by arc fitting according to the edge curvature information, and calculate the second center position of the second reference circle; perform centroid calculation on the first center position and the second center position to obtain the wafer center.

[0038] Optionally, before the extraction unit processes the collected wafer image frame by frame and extracts edge feature points of the wafer image, the device further includes a filtering unit 404 for: performing Gaussian filtering on the wafer image.

[0039] All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, and will not be repeated here.

[0040] In other embodiments of the present application, the present invention discloses an electronic device, such as Figure 5 As shown, the electronic device may include: one or more processors 501; a memory 502; a display 503; one or more applications (not shown); and one or more computer programs 504. The above components may be connected via one or more communication buses 505. The one or more computer programs 504 are stored in the memory 502 and configured to be executed by the one or more processors 501. The one or more computer programs 504 include instructions. The instructions may be used to execute the following: Figure 2 And each step in the corresponding embodiment.

[0041] Through the description of the above implementation methods, technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device and unit described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0042] Each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0043] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, electronic device, or network device, etc.) or a processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: flash memory, mobile hard disk, read-only memory, random access memory, disk or optical disk and other media that can store program code.

[0044] The above is only a specific implementation of the embodiment of the present invention, but the protection scope of the embodiment of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiment of the present invention should be included in the protection scope of the embodiment of the present invention. Therefore, the protection scope of the embodiment of the present invention should be based on the protection scope of the claims.

Claims

1. A wafer center positioning method, characterized in that: include: Acquiring wafer images, including rotating the wafer on a turntable and capturing wafer images frame by frame along the outer edge of the wafer, Acquire position information of at least three points of interest in the wafer image in a rectangular coordinate system; Using the at least three interest points to fit a first reference circle, and using the position information of the at least three interest points to calculate a first center position of the first reference circle; Extracting edge curvature information of the wafer image, including processing the collected wafer image frame by frame through an image vision algorithm and extracting edge feature points of the wafer image, fitting arcs according to the edge feature points, and obtaining edge curvature information of the wafer image; Obtain a second reference circle by arc fitting according to the edge curvature information, and calculate a second center position of the second reference circle; The centroids of the first circle center position and the second circle center position are calculated to obtain the wafer center.

2. The method according to claim 1, characterized in that Before processing the acquired wafer images frame by frame and extracting edge feature points of the wafer images, the following steps are also included: Gaussian filtering is performed on the wafer image.

3. The method according to claim 1 or 2, characterized in that: The selection intervals of the three interest points are not equal.

4. A wafer center positioning device, characterized in that: include: An acquisition unit is used to acquire a wafer image, wherein the turntable rotates the wafer and collects the wafer image frame by frame along the outer edge of the wafer, and acquires position information of at least three points of interest in the wafer image in a rectangular coordinate system; a processing unit, configured to obtain a first reference circle by fitting the at least three interest points, and calculate a first center position of the first reference circle by using position information of the at least three interest points; An extraction unit is used to extract the edge curvature information of the wafer image, and to process the collected wafer image frame by frame through an image vision algorithm and extract edge feature points of the wafer image, and fit an arc according to the edge feature points to obtain the edge curvature information of the wafer image; The processing unit is further used to obtain a second reference circle by arc fitting according to the edge curvature information, calculate the second center position of the second reference circle; and perform centroid calculation on the first center position and the second center position to obtain the wafer center.

5. The device according to claim 4, characterized in that Before the extraction unit processes the collected wafer images frame by frame and extracts edge feature points of the wafer images, the device further includes a filtering unit for: Gaussian filtering is performed on the wafer image.

6. The device according to claim 4 or 5, characterized in that The selection intervals of the three interest points are not equal.

7. An electronic device, characterized in that: include: A processor and a memory, wherein the memory is used to store a computer program; The processor is configured to execute the computer program stored in the memory so as to enable the electronic device to perform the method according to any one of claims 1 to 3.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.

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