Wafer die standard graph generation method, device and equipment and storage medium

Abstract

The invention relates to the technical field of semiconductors, and discloses a wafer die standard image generation method, device and equipment and a storage medium, and the method comprises the steps: collecting a plurality of current visual field images of a complete die in a wafer, carrying out the template matching of the plurality of current visual field images according to a matching template image, and obtaining a die standard image; obtaining a first feature region in the successfully matched matching template image and a corresponding second feature region in each current view image, calculating radial distortion between the first feature region and each second feature region to obtain a radial distortion coefficient, and correcting each current view image according to the radial distortion coefficient to obtain a corrected current view image. According to the method and the device, the current view images are obtained, the corrected view images corresponding to the current view images are obtained, the corrected view images are spliced to obtain the spliced image, and the wafer die standard image is generated according to the spliced image, so that splicing deviation can be avoided, and the accuracy of manufacturing the wafer die standard image is ensured.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method, device, equipment and storage medium for generating a wafer die standard image. Background Art

[0002] In wafer defect detection, the wafer die standard image is very important. 1. In traditional detection algorithms, the standard image is used as the reference image for positioning the field of view image; 2. In differential detection, the standard image is used as the subtracted image. If the size and die pattern of the standard image are significantly different from those in the field of view image, defects may be missed or over-detected during the detection process, resulting in unsatisfactory detection results. Therefore, it is crucial to obtain a wafer die standard image with high accuracy.

[0003] Especially when the field of view is smaller than the die, one field of view image cannot present a complete die image. Multiple field of view images are stitched together to obtain a complete die image. During the stitching process, pixel offsets often occur at the position of the stitching seams, causing problems when the image algorithm is used for detection. There are many reasons for the offset in stitching, such as camera lens shake, lens distortion, and low axis accuracy. Therefore, how to avoid pixel offsets at the position of the stitching seams during the stitching process, resulting in low accuracy of the generated wafer die standard image, which in turn affects the accuracy of defect detection, is a technical problem that needs to be solved urgently.

[0004] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of the present invention is to provide a method, device, equipment and storage medium for generating a wafer die standard image, aiming to solve the technical problem in the prior art that the position pixel offset of the splicing seam during the splicing process leads to the low accuracy of the generated wafer die standard image, thereby affecting the accuracy of defect detection.

[0006] To achieve the above object, the present invention provides a method for generating a wafer die standard image, the method comprising the following steps:

[0007] Collect multiple current field of view images of a complete die in the wafer;

[0008] Performing template matching on the multiple current field of view images according to the matching template image to obtain a first feature area in the successfully matched matching template image and a corresponding second feature area in each of the current field of view images;

[0009] Calculating the radial distortion between the first characteristic region and each of the second characteristic regions to obtain a radial distortion coefficient;

[0010] Correct each of the current field-of-view images according to the radial distortion coefficient to obtain the corrected field-of-view images corresponding to each of the current field-of-view images;

[0011] Stitch the corrected field-of-view images to obtain a stitched image;

[0012] Generate a standard wafer die map according to the stitched image.

[0013] Preferably, before performing template matching on the multiple current field-of-view images according to the matching template image, it further includes:

[0014] Calculate the seg position information and the overlapping regions between the current field-of-view images according to the multiple current field-of-view images;

[0015] Create a matching template image according to the seg position information and the overlapping regions between the current field-of-view images.

[0016] Preferably, calculating the seg position information and the overlapping regions between the current field-of-view images according to the multiple current field-of-view images includes:

[0017] Calculate the seg position information and the overlapping regions between the field-of-view images according to the overlapping pixels, the image width and height dimensions, and the die dimensions of the multiple current field-of-view images.

[0018] Preferably, generating a standard wafer die map according to the stitched image includes:

[0019] Calculate the center point and the rotation angle of the die according to the stitched image;

[0020] Rotate and crop the stitched image according to the center point and the rotation angle of the die to obtain multiple die images;

[0021] Calculate the median image of the multiple die images as the standard wafer die map.

[0022] Preferably, performing template matching on the multiple current field-of-view images according to the matching template image to obtain the first feature region in the successfully matched matching template image and the corresponding second feature regions in the current field-of-view images includes:

[0023] According to the matching template image, calculate the matching region of each of the current field-of-view images according to the rule of overlapping the field-of-view maps of the complete die up, down, left, and right, and obtain the first feature region in the successfully matched matching template image and the corresponding second feature regions in the current field-of-view images.

[0024] Preferably, calculating the radial distortion between the first feature region and each of the second feature regions to obtain a radial distortion coefficient includes:

[0025] Extracting a first contour of the first feature region and a second contour of the second feature region;

[0026] Extracting feature points from the first contour and the second contour at a preset pixel point interval to obtain a corresponding first set of feature points and a second set of feature points respectively;

[0027] Calculating the radial distortion coefficient between the matching template image and the current field of view image according to the first set of feature points and the second set of feature points.

[0028] Preferably, stitching the corrected field of view images to obtain a stitched image includes:

[0029] Calculating the correspondence between the first set of feature points and each of the second sets of feature points to obtain a projection transformation matrix between the matching template image and each of the current field of view images;

[0030] Stitching the corrected field of view images according to the projection transformation matrix between the matching template image and each of the current field of view images and the row-column stitching relationship to obtain a stitched image.

[0031] In addition, to achieve the above object, the present invention also provides a wafer die standard map generating device, which includes:

[0032] An acquisition module for acquiring a plurality of current field of view images of a complete die in a wafer;

[0033] A matching module for performing template matching on the plurality of current field of view images according to a matching template image to obtain a first feature region in the successfully matched matching template image and corresponding second feature regions in each of the current field of view images;

[0034] A calculation module for calculating the radial distortion between the first feature region and each of the second feature regions to obtain a radial distortion coefficient;

[0035] A correction module for correcting each of the current field of view images according to the radial distortion coefficient to obtain a corrected field of view image corresponding to each of the current field of view images;

[0036] A stitching module for stitching the corrected field of view images to obtain a stitched image;

[0037] A generation module for generating a wafer die standard map according to the stitched image.

[0038] In addition, to achieve the above object, the present invention further provides a wafer die standard map generation device, which includes a memory, a processor, and a wafer die standard map generation program stored on the memory and executable on the processor. The wafer die standard map generation program is configured to implement the steps of the wafer die standard map generation method as described above.

[0039] In addition, to achieve the above object, the present invention further provides a storage medium on which a wafer die standard map generation program is stored. When the wafer die standard map generation program is executed by a processor, it implements the steps of the wafer die standard map generation method as described above.

[0040] In the present invention, by collecting multiple current field-of-view images of a complete die in a wafer, performing template matching on the multiple current field-of-view images according to a matching template image, obtaining a first feature region in the successfully matched template image and corresponding second feature regions in each of the current field-of-view images, calculating the radial distortion between the first feature region and each of the second feature regions to obtain a radial distortion coefficient, correcting each of the current field-of-view images according to the radial distortion coefficient to obtain corrected field-of-view images corresponding to each of the current field-of-view images, splicing the corrected field-of-view images to obtain a spliced image, generating a wafer die standard map according to the spliced image, calculating the relative relationship between each image according to the result of the template matching, and then splicing, it is possible to avoid offset during splicing, thereby ensuring the accuracy of manufacturing the wafer die standard map. Description of the Drawings

[0041] Figure 1 is a schematic structural diagram of a wafer die standard map generation device in the hardware operating environment related to the embodiment solution of the present invention;

[0042] Figure 2 is a schematic flowchart of the first embodiment of the wafer die standard map generation method of the present invention;

[0043] Figure 3 is the current field-of-view image 1 in the first embodiment of the wafer die standard map generation method of the present invention;

[0044] Figure 4 is the current field-of-view image 2 in the first embodiment of the wafer die standard map generation method of the present invention;

[0045] Figure 5 is the spliced image in the first embodiment of the wafer die standard map generation method of the present invention;

[0046] Figure 6 is a structural block diagram of the first embodiment of the wafer die standard map generation device of the present invention;

[0047] Figure 7 This is the structural block diagram of the first embodiment of the wafer die standard map generation system of the present invention.

[0048] The realization of the purpose, functional characteristics and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Specific embodiments

[0049] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0050] Refer to Figure 1 , Figure 1 This is the structural schematic diagram of the wafer die standard map generation device in the hardware operating environment involved in the embodiment solution of the present invention.

[0051] As Figure 1 shown, the wafer die standard map generation device may include: a processor 1001, such as a Central Processing Unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display), and optionally the user interface 1003 may further include a standard wired interface and a wireless interface. For the wired interface of the user interface 1003, it may be a USB interface in the present invention. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a Wireless-Fidelity (WI-FI) interface). The memory 1005 may be a high-speed Random Access Memory (RAM) memory or a stable memory (Non-volatile Memory, NVM), such as a disk memory. The memory 1005 may optionally be a storage device independent of the aforementioned processor 1001.

[0052] Those skilled in the art can understand that Figure 1 the structure shown in

[0053] As Figure 1 shown, in the memory 1005 as a computer storage medium, there may be included an operating system, a network communication module, a user interface module, and a wafer die standard map generation program.

[0054] In Figure 1In the wafer die standard diagram generation device shown, the network interface 1004 is mainly used to connect to the background server and communicate data with the background server; the user interface 1003 is mainly used to connect to the user device; the wafer die standard diagram generation device calls the wafer die standard diagram generation program stored in the memory 1005 through the processor 1001 and executes the wafer die standard diagram generation method provided by the embodiments of the present invention.

[0055] Based on the above hardware structure, an embodiment of the wafer die standard diagram generation method of the present invention is proposed.

[0056] Referring to Figure 2 , a first embodiment of the wafer die standard diagram generation method of the present invention is proposed.

[0057] In the first embodiment, the wafer die standard diagram generation method includes the following steps:

[0058] Step S10: Collect multiple current field-of-view images of a complete die in the wafer.

[0059] It should be noted that the execution subject of this embodiment is the wafer die standard diagram generation device. Among them, the wafer die standard diagram generation device can be an electronic device such as a personal computer or a server, and this embodiment does not limit this. According to the image size, pixel accuracy, overlapping pixels, and the actual size of a complete die, calculate the camera photographing points where multiple pictures can cover the entire die. At the calculated camera photographing points, collect multiple current field-of-view images, and the multiple collected current field-of-view images can cover a complete die.

[0060] Step S20: Perform template matching on the multiple current field-of-view images according to the matching template image to obtain the first feature region in the successfully matched matching template image and the corresponding second feature regions in the current field-of-view images.

[0061] It can be understood that the field-of-view map is matched according to preset rules and regions, and the created matching template image is used for matching.

[0062] Further, in this embodiment, before step S20, it further includes:

[0063] Calculate the seg position information and the overlapping regions between the current field-of-view images according to the multiple current field-of-view images;

[0064] Create a matching template image according to the seg position information and the overlapping regions between the current field-of-view images.

[0065] It should be noted that the seg position information is the coordinates and area of a partial die area in the field of view image relative to the standard complete die image. The overlapping area between each of the current field of view images is specifically calculated based on the overlapping pixels, the width and height dimensions of the image, and the die size to obtain the seg position information and the overlapping area between each of the current field of view images.

[0066] Further, in this embodiment, calculating the seg position information and the overlapping area between each of the current field of view images based on the multiple current field of view images includes:

[0067] Calculating the seg position information and the overlapping area between the field of view images based on the overlapping pixels, the width and height dimensions of the image, and the die size of the multiple current field of view images.

[0068] Further, in this embodiment, step S20 includes:

[0069] According to the matching template image, calculating the matching area of each of the current field of view images according to the rule of overlapping the field of view of the complete die up, down, left, and right, and obtaining the first feature area in the matching template image that matches successfully and the corresponding second feature areas in each of the current field of view images.

[0070] It should be understood that as Figure 3 , Figure 4 shown, Figure 3 is the current field of view image 1, Figure 4 is the current field of view image 2, Figure 3 In the current field of view image 1, the green area in the right boundary is the area that matches successfully with the matching template image, that is, the overlapping area. Figure 4 In the current field of view image 2, the green area in the left boundary is the area that matches successfully with the matching template image, that is, the overlapping area.

[0071] Step S30: Calculate the radial distortion between the first feature area and each of the second feature areas to obtain the radial distortion coefficient.

[0072] It should be understood that the coordinates and contour of the matching template image are obtained, and the affine transformation matrix of the matching area between the matching template image and each current field of view image is calculated, that is, the positional relationship of the overlapping areas of each field of view up, down, left, and right is calculated. In the first feature area of the matching template image, the first contour is extracted. In the matched second feature area, the second contour is extracted. The first contour and the second contour are used to obtain the first feature point set and the second feature point set at a set pixel point interval. By automatically finding the corresponding relationship between the points, the projection transformation matrix and the radial distortion coefficient between the two images are calculated.

[0073] Further, in this embodiment, step S30 includes: extracting the first contour of the first feature region and the second contour of the second feature region; extracting feature points at a preset pixel point interval from the first contour and the second contour to obtain corresponding first and second feature point sets respectively; and calculating the radial distortion coefficient between the matching template image and the current field of view image according to the first and second feature point sets.

[0074] It should be noted that first, the gray value correlation of the mask windows around the feature points of the first feature point set and each second feature point set is determined, and the similarity of the windows in the matching template image and the current field of view image is used to generate an initial match between the matching template image and the current field of view image. Then, by setting the size and offset of a rectangle, the search area of the current field of view image is preset as a rectangle. For the points within the window, the offset of the center of the search window in the matching template image relative to the position of the current point in the current field of view image is calculated. If the current field of view image is rotated relative to the matching template image, the calculation of the rotation angle is also included. After the initial match, a random search algorithm is used to calculate the projective transformation matrix and the radial distortion coefficient between the matching template image and the current field of view image.

[0075] Step S40: Correct each current field of view image according to the radial distortion coefficient to obtain a corrected field of view image corresponding to each current field of view image.

[0076] In a specific implementation, the field of view image of the die is corrected according to the radial distortion coefficient to obtain a corrected field of view image.

[0077] Step S50: Stitch each corrected field of view image to obtain a stitched image.

[0078] It should be noted that the images are stitched according to the transformation matrix and the stitching relationship.

[0079] Further, in this embodiment, step S50 includes:

[0080] Calculating the correspondence between the first feature point set and each second feature point set to obtain the projective transformation matrix between the matching template image and each current field of view image;

[0081] According to the projective transformation matrix between the matching template image and each current field of view image, and the row and column stitching relationship, each corrected field of view image is stitched to obtain a stitched image.

[0082] It should be understood that the projection transformation matrix between two images is calculated by calculating the correspondence between the first set of feature points and each of the second sets of feature points. Stitching the images: Stitch the images according to the transformation matrix and the row-column stitching relationship between the field-of-view images, and the stitching relationship is calculated based on the overlapping pixels between the rows and columns of the field-of-view images.

[0083] Step S60: Generate a standard wafer die map according to the stitched map.

[0084] In a specific implementation, as Figure 5 shown, Figure 5 is Figure 3 the stitched map formed after stitching the field-of-view maps of Figure 4 . Calculate the center point and rotation angle of the die according to the stitched map. Then crop the die image: Rotate and crop the stitched map according to the center point and angle of the die to obtain the die image. Calculate the standard map: Calculate the median image of multiple die images as the standard wafer die map.

[0085] Furthermore, in this embodiment, the step S60 includes:

[0086] Calculate the center point and rotation angle of the die according to the stitched map;

[0087] Rotate and crop the stitched map according to the center point and rotation angle of the die to obtain multiple die images;

[0088] Calculate the median image of the multiple die images as the standard wafer die map.

[0089] In this embodiment, feature positioning and radial distortion correction can solve the problem of pixel offset at the stitching seam position when generating the standard wafer die map, ensure the accuracy of the standard wafer die map, and also greatly improve the accuracy of defect detection.

[0090] In addition, an embodiment of the present invention also provides a storage medium, on which a program for generating a standard wafer die map is stored. When the program for generating a standard wafer die map is executed by a processor, the steps of the method for generating a standard wafer die map as described above are implemented.

[0091] In addition, referring to Figure 6 , an embodiment of the present invention also provides a device for generating a standard wafer die map. The device for generating a standard wafer die map includes:

[0092] An acquisition module 10, configured to acquire multiple current field-of-view images of a complete die in a wafer;

[0093] A matching module 20, configured to perform template matching on multiple current field-of-view images according to a matching template image, and obtain a first feature region in the successfully matched matching template image and corresponding second feature regions in each of the current field-of-view images;

[0094] A calculation module 30, configured to calculate the radial distortion between the first feature region and each of the second feature regions, and obtain a radial distortion coefficient;

[0095] A correction module 40, configured to correct each of the current field-of-view images according to the radial distortion coefficient, and obtain a corrected field-of-view image corresponding to each of the current field-of-view images;

[0096] A stitching module 50, configured to stitch each of the corrected field-of-view images to obtain a stitched image;

[0097] A generation module 60, configured to generate a standard wafer die map according to the stitched image.

[0098] For other embodiments or specific implementation manners of the wafer die standard map generation device of the present invention, reference may be made to the above method embodiments, which will not be elaborated herein.

[0099] In addition, referring to Figure 7 , based on the first embodiment of the above method, an embodiment of the present invention further provides a wafer die standard map generation system, where the wafer die standard map generation system includes: a wafer die standard map generation device 100 as shown in Figure 1 , a microscopic imaging module 200, and a high-precision motion platform 300; the wafer die standard map generation device 100 is respectively connected to the microscopic imaging module 200 and the high-precision motion platform 300, the microscopic imaging module 200 is disposed on the high-precision motion platform 300, and the wafer die standard map generation device 100 controls the microscopic imaging module 200 to collect a field-of-view map of a wafer to be detected. Usually, the wafer is placed on a chunk disk, the wafer is scanned and the obtained current field-of-view images are saved, the chunk disk is placed on the high-precision motion platform 300, and the wafer die standard map generation device 100 controls the high-precision motion platform 300 to move to implement the scanning of the entire wafer disk.

[0100] It should be noted that, in this article, the terms "include", "comprise" or any other variation thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the phrase "including one..." does not exclude the existence of additional identical elements in the process, method, article or system including the element.

[0101] The serial numbers of the embodiments of the present invention above are only for description and do not represent the superiority or inferiority of the embodiments. Among the unit claims listing several devices, several of these devices may be embodied by the same hardware item. The use of the terms "first", "second", and "third", etc. does not indicate any order, and these terms may be interpreted as identifiers.

[0102] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as a Read Only Memory image (ROM) / Random Access Memory (RAM), magnetic disk, optical disc), and includes several instructions for causing a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0103] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A method for generating a wafer die standard image, characterized in that: The wafer die standard image generation method comprises the following steps: Collect multiple current field of view images of a complete die in the wafer; Performing template matching on the multiple current field of view images according to the matching template image to obtain a first feature area in the successfully matched matching template image and a corresponding second feature area in each of the current field of view images; Calculating the radial distortion between the first characteristic region and each of the second characteristic regions to obtain a radial distortion coefficient; Correcting each of the current field of view images according to the radial distortion coefficient to obtain a corrected field of view image corresponding to each of the current field of view images; Stitching the corrected visual field images to obtain a stitching image; A wafer die standard image is generated according to the stitching image.

2. The method for generating a wafer die standard image according to claim 1, wherein: Before performing template matching on the multiple current field of view images according to the matching template image, the method further includes: Calculating seg position information and overlapping areas between the current field of view images according to the multiple current field of view images; A matching template image is created according to the seg position information and the overlapping area between the current field of view images.

3. The method for generating a wafer die standard image according to claim 2, wherein: Calculating seg position information and overlapping areas between the current field of view images according to the multiple current field of view images includes: According to the overlapping pixels, image width and height dimensions and die size of the multiple current field of view images, the seg position information and the overlapping area between the field of view images are calculated.

4. The method for generating a wafer die standard image according to claim 1, wherein: According to the stitching diagram, a wafer die standard diagram is generated, including: According to the splicing graph, the center point and rotation angle of the die are calculated; Rotate and crop the mosaic image according to the center point and rotation angle of the die to obtain multiple die images; Calculate the median image of the multiple die images as the wafer die standard image.

5. The method for generating a wafer die standard image according to claim 1, wherein: Performing template matching on the multiple current field of view images according to the matching template image to obtain a first feature area in the successfully matched matching template image and a corresponding second feature area in each of the current field of view images, including: According to the matching template image, the matching area of ​​each current field of view image is calculated for the multiple current field of view images according to the rule that the field of view of the complete die overlaps up and down and left and right, and the first feature area in the successfully matched matching template image and the corresponding second feature area in each current field of view image are obtained.

6. The method for generating a wafer die standard image as claimed in any one of claims 1 to 5, characterized in that: Calculating the radial distortion between the first characteristic region and each of the second characteristic regions to obtain a radial distortion coefficient includes: Extracting a first contour of the first feature area, and extracting a second contour of the second feature area; Extracting feature points from the first contour and the second contour according to a preset pixel point interval to obtain a first feature point set and a second feature point set corresponding to each other; A radial distortion coefficient between the matching template image and the current field of view image is calculated according to the first feature point set and the second feature point set.

7. The method for generating a wafer die standard image according to claim 6, wherein: The corrected visual field images are stitched together to obtain a stitched image, including: Calculating the correspondence between the first feature point set and each of the second feature point sets to obtain a projection transformation matrix between the matching template image and each of the current field of view images; According to the projection transformation matrix between the matching template image and each of the current field of view images, and the row-column splicing relationship, each of the corrected field of view images is spliced ​​to obtain a spliced ​​image.

8. A wafer die standard image generating device, characterized in that: The wafer die standard image generating device comprises: The acquisition module is used to acquire multiple current field of view images of a complete die in the wafer; A matching module, used for performing template matching on the multiple current field of view images according to a matching template image, to obtain a first feature region in the successfully matched matching template image and a corresponding second feature region in each of the current field of view images; A calculation module, used for calculating the radial distortion between the first characteristic region and each of the second characteristic regions, and obtaining a radial distortion coefficient; A correction module, used for correcting each of the current field of view images according to the radial distortion coefficient to obtain a corrected field of view image corresponding to each of the current field of view images; A stitching module, used for stitching the corrected visual field images to obtain a stitching image; A generation module is used to generate a wafer die standard image according to the stitching image.

9. A wafer die standard image generating device, characterized in that: The wafer die standard image generating device comprises: a memory, a processor, and a wafer die standard image generating program stored in the memory and executable on the processor. When the wafer die standard image generating program is executed by the processor, the steps of the wafer die standard image generating method as described in any one of claims 1 to 7 are implemented.

10. A storage medium, characterized in that: The storage medium stores a wafer die standard image generation program, and when the wafer die standard image generation program is executed by the processor, the steps of the wafer die standard image generation method according to any one of claims 1 to 7 are implemented.

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