Method and device for detecting cut wafer, computer equipment and storage medium

Abstract

The invention relates to a cut wafer detection method and device, computer equipment and a storage medium, and the method comprises the steps: carrying out the large-view shooting, so as to obtain a complete wafer photo; according to the complete wafer photo, obtaining separation points among a plurality of dies formed by cutting the wafer; acquiring a shooting track according to the separation points; according to the shooting track, small-view shooting is adopted to obtain a plurality of local wafer photos; according to the shooting track, obtaining a die to which each local wafer photo belongs; acquiring overlapped pixels of adjacent local wafer photos according to the shooting track and the sizes of the local wafer photos; splicing the local wafer photos belonging to the target die into a spliced image containing the target die according to the shooting track and the overlapped pixels; and segmenting a target die complete image from the spliced image containing the target die so as to detect the cut wafer. According to the invention, local wafer photos can be spliced into a complete die graph, and resources are saved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and particularly to a method, device, computer equipment and storage medium for detecting a wafer after cutting. Background Art

[0002] A wafer refers to a silicon wafer used for fabricating silicon semiconductor circuits. Wafer dicing, also known as wafer cutting, refers to the process of cutting a single wafer into multiple independent chips / integrated circuits / wafers / grains. The chips / integrated circuits / wafers / grains cut from the wafer can also be referred to as dies. The mainstream wafer dicing methods generally include mechanical dicing, laser dicing, etc.

[0003] Whether it is mechanical dicing or laser dicing, it is possible to cause damage to the edges, corners or even other positions of the die, that is, defective products are generated. Therefore, after wafer cutting, it is necessary to check whether the chips are qualified through a high-definition camera. In order to better check whether the cut chips are qualified, the high-definition camera has a high clarity but a small field of view. Therefore, usually multiple photos need to be taken for one chip, and then the photos are stitched together for inspection.

[0004] In the prior art, in the process of wafer processing and dicing, in order to protect the wafer and chips, a blue film is pasted on one or both sides of the wafer. After wafer cutting, the blue film will deform and the deformation is irregular, resulting in irregular arrangement of the cut chips. And the detection method in the prior art to solve the problem of irregular arrangement of the cut chips is to increase the shooting range of the high-definition camera, that is, to take more photos for one cut chip, which makes the inspection process consume more storage resources and computing resources, with high cost and low efficiency. Summary of the Invention

[0005] In order to solve the above technical problems or at least partially solve the above technical problems, the present invention provides a method, device, computer equipment and storage medium for detecting a wafer after cutting.

[0006] In a first aspect, the present invention provides a method for detecting a wafer after cutting, the method comprising: Performing large-field shooting to obtain a complete wafer photo; According to the complete wafer photo, obtaining separation points between a plurality of dies formed by cutting the wafer; According to the separation points, obtaining a shooting trajectory; According to the shooting trajectory, performing small-field shooting to obtain a plurality of partial wafer photos; According to the shooting trajectory, obtaining the die to which each of the partial wafer photos belongs; According to the shooting trajectory and the size of the partial wafer photos, obtaining overlapping pixels of adjacent partial wafer photos; According to the shooting trajectory and the overlapping pixels, splice the partial wafer photos belonging to the target die into a spliced image including the target die; Extract a complete image of the target die from the spliced image including the target die to detect the wafer after cutting; Wherein, the size of each partial wafer photo is smaller than the size of a complete die.

[0007] Optionally, the obtaining the shooting trajectory according to the separation points includes: Obtain the distance between every two adjacent separation points as the first distance; Obtain the maximum value among all the first distances as the second distance; Obtain the shooting trajectory according to the second distance and the partial wafer photo size.

[0008] Optionally, the shooting trajectory includes a scanning path and shooting points, The obtaining the shooting trajectory according to the second distance and the partial wafer photo size includes: Obtain the number of shooting images between every two adjacent separation points according to the second distance and the partial wafer photo size; Obtain the shooting points according to the number of shooting images; Plan the scanning path according to the shooting points; Wherein, the number of shooting images includes the number of shooting images on the X-axis and the number of shooting images on the Y-axis, and the scanning path is the sequence of multiple shooting points.

[0009] Optionally, the obtaining the overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photo includes: Obtain the point distance between adjacent shooting points in the shooting trajectory; Obtain the overlapping pixels according to the point distance and the size of the partial wafer photo; Wherein, the overlapping pixels include overlapping pixels on the X-axis and overlapping pixels on the Y-axis.

[0010] Optionally, splicing the partial wafer photos belonging to the target die into a spliced image including the target die according to the shooting trajectory and the overlapping pixels includes: Obtain the position of the shooting point in the partial wafer photo as the shooting position; Obtain the point coordinates of each shooting point in the small field-of-view coordinate system according to the shooting trajectory and the shooting position; Obtain the coordinate range of each partial wafer photo according to the partial wafer photo size, the point coordinates and the shooting position; Obtain the coordinate range of the complete die map based on the coordinate range of the local wafer photo, the shooting trajectory, and the overlapping pixels; Obtain the position of the divided area according to the coordinate range of the local wafer photo and the coordinate range of the complete die map; Stitch the local wafer photos belonging to the target die into a stitched image containing the target die according to the position of the divided area; Among them, the position of the divided area is used to indicate the position of a partial die area in the local wafer photo relative to the complete die map.

[0011] Optionally, after splitting the complete map of the target die from the stitched image containing the target die, the method further includes: Obtain the conversion parameters from the small field of view coordinate system to the large field of view coordinate system according to the lens magnification, the scaling factor of sampling, and the pixel accuracy; Obtain the position of the complete map of the target die in the complete wafer photo according to the conversion parameters; Among them, the lens magnification is the lens magnification from the large field of view to the small field of view.

[0012] In a second aspect, a post-cut wafer detection device is provided, and the device includes: A shooting unit for shooting with a large field of view to obtain a complete wafer photo; A separation point acquisition unit for obtaining separation points between a plurality of dies formed by cutting the wafer according to the complete wafer photo; A trajectory acquisition unit for obtaining a shooting trajectory according to the separation points; The shooting unit is further configured to shoot with a small field of view according to the shooting trajectory to obtain a plurality of local wafer photos; A stitching unit for obtaining the die to which each local wafer photo belongs according to the shooting trajectory; The stitching unit is further configured to obtain overlapping pixels of adjacent local wafer photos according to the shooting trajectory and the size of the local wafer photos; The stitching unit is further configured to stitch the local wafer photos belonging to the target die into a stitched image containing the target die according to the shooting trajectory and the overlapping pixels; The stitching unit is further configured to split the complete map of the target die from the stitched image containing the target die to detect the post-cut wafer; Among them, the size of each local wafer photo is smaller than the size of a complete die.

[0013] Optionally, the splicing unit is further configured to: Obtain the position of the shooting point in the local wafer photo as the shooting position; According to the shooting trajectory and the shooting position, obtain the point coordinates of each shooting point in the small field-of-view coordinate system; According to the local wafer photo size, the point coordinates and the shooting position, obtain the coordinate range of each local wafer photo; According to the coordinate range of the local wafer photo, the shooting trajectory and the overlapping pixels, obtain the coordinate range of the complete die map; According to the coordinate range of the local wafer photo and the coordinate range of the complete die map, obtain the divided area position; According to the divided area position, splice the local wafer photos belonging to the target die into a spliced image including the target die; Wherein, the divided area position is used to indicate the position of a partial die area in the local wafer photo relative to the complete die map.

[0014] In a third aspect, a computer device is provided, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method described in any one of the above is implemented.

[0015] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method described in any one of the above is implemented.

[0016] The present invention provides a method, apparatus, computer device and storage medium for detecting a wafer after cutting. The method includes: performing large-field shooting to obtain a complete wafer photo; obtaining separation points between a plurality of dies formed by cutting the wafer according to the complete wafer photo; obtaining a shooting trajectory according to the separation points; performing small-field shooting according to the shooting trajectory to obtain a plurality of partial wafer photos; obtaining the die to which each partial wafer photo belongs according to the shooting trajectory; obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos; splicing the partial wafer photos belonging to the target die into a spliced image including the target die according to the shooting trajectory and the overlapping pixels; and segmenting a complete target die image from the spliced image including the target die to detect the wafer after cutting; wherein the size of each partial wafer photo is smaller than the size of a complete die. In the method of the embodiment of the present invention, large-field shooting is first performed to obtain a complete wafer photo; separation points between a plurality of dies formed by cutting the wafer are obtained according to the complete wafer photo; and then it is converted to small-field shooting to obtain a plurality of partial wafer photos. When taking small-field photos, shooting is performed according to the shooting trajectory, then the die to which each partial wafer photo belongs is determined, and overlapping pixels are obtained, and then splicing is performed according to the shooting trajectory and the overlapping pixels, and a complete target die image is segmented from the spliced image. Compared with the method of identifying the overlapping area by image recognition and then performing splicing, the method of the embodiment of the present invention directly performs splicing through overlapping pixels, which can save a large amount of image recognition processes, improve the splicing speed, save system resources, and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0019] Figure 1 The following shows an application environment diagram of the method for detecting a wafer after cutting according to an embodiment of the present invention; Figure 2 The following shows a flowchart of the method for detecting a wafer after cutting according to an embodiment of the present invention; Figure 3 The following shows a schematic diagram of a complete wafer photo according to an embodiment of the present invention; Figure 4 The following shows a schematic diagram of a partial enlargement of the complete wafer photo according to an embodiment of the present invention; Figure 5 The figure shows a schematic diagram of multiple partial wafer photos according to an embodiment of the present invention; Figure 6 The figure shows a schematic diagram of a scanning path according to an embodiment of the present invention; Figure 7 The figure shows a schematic diagram of a scanning path according to an embodiment of the present invention; Figure 8 The figure shows a spliced image including the target die according to an embodiment of the present invention; Figure 9 The figure shows a schematic diagram of a complete die map after splicing according to an embodiment of the present invention; Figure 10 The figure shows a schematic diagram of a wafer inspection device after cutting according to an embodiment of the present invention; Figure 11 The figure shows an internal structure diagram of a computer device in an embodiment of the present invention. Detailed implementation manners

[0020] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Figure 1 The figure shows an application environment diagram of a method for inspecting a wafer after cutting according to an embodiment of the present invention. Refer to Figure 1 , this method for inspecting a wafer after cutting is applied to a system for inspecting a wafer after cutting. This method for inspecting a wafer after cutting includes a terminal 110 and / or a server 120. The terminal 110 and the server 120 are connected through a network. The terminal 110 may specifically be a desktop terminal or a mobile terminal, and the mobile terminal may specifically be at least one of a mobile phone, a tablet computer, a laptop computer, etc. The server 120 may be implemented by an independent server or a server cluster composed of multiple servers.

[0022] The method for inspecting a wafer after cutting of the present invention is applied to the terminal 110 and / or the server 120.

[0023] Figure 2 The figure shows a flowchart of a method for inspecting a wafer after cutting according to an embodiment of the present invention. As Figure 2 shown, the method includes: Step 210, performing large-field shooting to obtain a complete wafer photo; Step 220: Obtain the separation points between multiple dies formed by cutting the wafer according to the complete wafer photo. Step 230: Obtain the shooting trajectory according to the separation points. Step 240: Take small-field photos according to the shooting trajectory to obtain multiple partial wafer photos. Step 250: Obtain the die to which each of the partial wafer photos belongs according to the shooting trajectory. Step 260: Obtain the overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos. Step 270: Stitch the partial wafer photos belonging to the target die into a stitched image containing the target die according to the shooting trajectory and the overlapping pixels. Step 280: Segment the complete image of the target die from the stitched image containing the target die to detect the cut wafer.

[0024] Wherein, the size of each partial wafer photo is smaller than the size of a complete die.

[0025] The large-field photo taking and the small-field photo taking can be performed by the same camera at different focal lengths or by different cameras. Whether it is the same camera or different cameras, calibration and / or detection need to be performed before detection to confirm the transformation parameters for the transformation from the large field of view to the small field of view.

[0026] The transformation parameters can include the lens magnification, the scaling factor of sampling, and the pixel accuracy, etc. The transformation parameters can be used for coordinate system transformation. For example, the coordinates of a certain point in the large-field coordinate system can be transformed into the coordinates in the small-field coordinate system through the transformation parameters. Similarly, the coordinates in the small-field coordinate system can be transformed into the coordinates in the large-field coordinate system through the transpose of the transformation parameters.

[0027] The separation points in the embodiments of the present invention refer to the points where the boundaries of different dies after wafer cutting intersect.

[0028] Figure 3 The figure shows a schematic diagram of the complete wafer photo in the embodiments of the present invention. Figure 3 In the figure, since it is a large-field photo taking, each die in the wafer is relatively small and the pixels are low, which is not convenient for subsequent detection.

[0029] Figure 3 In the figure, each green frame can be regarded as a die after cutting. The intersection points of the green lines can be used as the separation points.

[0030] Figure 4The figure shows a partially enlarged schematic diagram of a complete wafer photo according to an embodiment of the present invention. As Figure 4 shown, the separation point 410 can be considered as the center of the cross. Figure 4 There are multiple separation points in it, and only one is marked.

[0031] Large-field shooting can capture a larger field of view, so a complete wafer photo can be captured. However, the accuracy and clarity are small, making it difficult to distinguish and perform subsequent inspections. Small-field photography has high precision and high clarity and can be used to detect whether the die after wafer cutting is damaged, etc. To ensure high clarity and high precision, it is difficult for small-field photography to capture a complete die. Therefore, multiple partial wafer photos need to be stitched together into a complete die map.

[0032] In the method of the embodiment of the present invention, first, large-field shooting is adopted to obtain a complete wafer photo; according to the complete wafer photo, the separation points between multiple dies formed by wafer cutting are obtained; then, it is converted to small-field shooting to obtain multiple partial wafer photos. When taking small-field photos, shooting is performed according to the shooting trajectory, and then it is determined which die each of the partial wafer photos belongs to, and the overlapping pixels are obtained. Then, stitching is performed according to the shooting trajectory and the overlapping pixels, and the complete map of the target die is segmented from the stitched image. Compared with the method of stitching by identifying the overlapping area through image recognition, the method of the embodiment of the present invention directly performs stitching through overlapping pixels, which can save a large amount of image recognition processes, improve the stitching speed, save system resources, and reduce costs.

[0033] In the embodiment of the present invention, in step 230, the obtaining of the shooting trajectory according to the separation points includes: Obtaining the distance between every two adjacent separation points as the first distance; Obtaining the maximum value among all the first distances as the second distance; Obtaining the shooting trajectory according to the second distance and the size of the partial wafer photo.

[0034] Reference Figure 3 、 Figure 4 shown, the separation points are actually the points where the boundaries between different dies intersect. The distance between adjacent separation points on the X-axis is approximately equivalent to the length of a die on the X-axis. Similarly, the distance between adjacent separation points on the Y-axis is approximately equivalent to the length of a die on the Y-axis.

[0035] Considering the clarity of the complete wafer photo and other errors in the selection of the separation points, in the method of the embodiment of the present invention, obtaining the shooting trajectory according to the maximum distance between the separation points can reduce subsequent errors.

[0036] The size of the partial wafer photo is usually rectangular or square, and reference can be made toFigure 5 as shown

[0037] In an embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points Obtaining the shooting trajectory according to the second distance and the local wafer photo size includes: Obtaining the number of shooting images between every two adjacent separation points according to the second distance and the local wafer photo size Obtaining the shooting points according to the number of shooting images Planning the scanning path according to the shooting points wherein, the number of shooting images includes the number of shooting images on the X-axis and the number of shooting images on the Y-axis, and the scanning path is the sequence of multiple shooting points

[0038] The number of shooting images on the X-axis can be obtained by dividing the second distance on the X-axis by the size of the local wafer photo on the X-axis, then rounding up, and adding 1 or 2

[0039] Rounding up is to ensure a certain margin and overlapping pixels, and adding 1 or 2 is to make the separation points in the local wafer photo located at or near the center of the field of view

[0040] In an embodiment of the present invention, assume that the second distance on the X-axis is 80 and the second distance on the Y-axis is 60. The size of the local wafer photo can be 30 on the X-axis and 30 on the Y-axis. At this time, it can be calculated that 4 or 5 images are taken on the X-axis and 3 or 4 images are taken on the Y-axis

[0041] Actually, the principle of obtaining the number of shooting images is that multiple local wafer photos can cover the entire die and there is a certain overlap between them

[0042] In an embodiment of the present invention, the scanning path can be row-by-row or column-by-column. When row-by-row, the scanning path can be unidirectional along the X-axis or bidirectional along the X-axis Figure 6 As shown in the schematic diagram of the scanning path of the embodiment of the present invention, when scanning row-by-row, from point C1 along the positive X-axis to point C2, return to the shooting point C3 of another row, and then along the positive X-axis to C4

[0043] Figure 7 As shown in the schematic diagram of the scanning path of the embodiment of the present invention, when scanning row-by-row, from point C1 along the positive X-axis to point C2, move down to the shooting point C4 of another row, and then along the negative X-axis to C3

[0044] In an embodiment of the present invention, the distance between two adjacent shooting points can be equidistant or non-equidistant. When non-equidistant, it is necessary to record the distance between every two adjacent shooting points respectively

[0045] In the embodiment of the present invention, the distance between two adjacent shooting points is preferably equidistant.

[0046] In the embodiment of the present invention, in step 250, obtaining the die to which each of the local wafer photos belongs according to the shooting trajectory includes: Obtaining the die to which each of the local wafer photos belongs according to the separation point and the shooting trajectory.

[0047] As Figure 4 、 Figure 5 、 Figure 6 shown, if according to the Figure 6 shooting trajectory, the shooting trajectory is from C1 to C2, then the local wafer photos between the first separation point along the X-axis to another separation point belong to the same die. Refer to Figure 5 , 1-1, 1-2, 1-3 and 1-4 are several local wafer photos between two separation points and belong to the same die, denoted as diaA. Of course, referring to Figure 5 shown, a part of these local wafer photos belongs to dieA, while other parts may belong to other dies. For example, the lower right part of 1-1, the lower half of 1-2, the lower half of 1-3 and the lower left part of 1-4 belong to dieA, while the upper left part, lower left part and upper right part of 1-1 belong to four different dies. Similarly, the upper half of 1-2 also belongs to other dies.

[0048] Referring to Figure 6 the shooting trajectory, according to the X-axis and Y-axis coordinates, the Y-axis coordinates of the center coordinates of 1-1 and 2-1 are the same, and 2-1 is the next row of 1-1 and there is no separation point, so it can also be confirmed that 2-1 belongs to dieA. Similarly, according to the coordinates and the shooting trajectory, it can be confirmed that 2-1, 2-3, 2-4 belong to dieA, while 3-1 and 3-4 have separation points, and it can be confirmed that 3-1, 3-2, 3-3 and 3-4 also belong to dieA.

[0049] In the embodiment of the present invention, obtaining the overlapping pixels of adjacent local wafer photos according to the shooting trajectory and the size of the local wafer photos includes: Obtaining the point distance between adjacent shooting points in the shooting trajectory; Obtaining the overlapping pixels according to the point distance and the size of the local wafer photos; wherein, the overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0050] In an embodiment of the present invention, in step 270, according to the shooting trajectory and the overlapping pixels, the partial wafer photos belonging to the target die are stitched into a stitched image including the target die, which includes: Obtain the position of the shooting point in the partial wafer photo as the shooting position; According to the shooting trajectory and the shooting position, obtain the point coordinates of each shooting point in the small field coordinate system; According to the partial wafer photo size, the point coordinates, and the shooting position, obtain the coordinate range of each partial wafer photo; According to the coordinate range of the partial wafer photo, the shooting trajectory, and the overlapping pixels, obtain the coordinate range of the complete die map; According to the coordinate range of the partial wafer photo and the coordinate range of the complete die map, obtain the divided area position; According to the divided area position, stitch the partial wafer photos belonging to the target die into a stitched image including the target die; Wherein, the divided area position is used to indicate the position of a partial die area in the partial wafer photo relative to the complete die map.

[0051] In an embodiment of the present invention, "divided area" can also be denoted as seg.

[0052] Figure 5 The figure shows a schematic diagram of multiple partial wafer photos in an embodiment of the present invention. For ease of description, the multiple partial wafer photos are numbered from left to right and top to bottom as 1-1, 1-2, 1-3, 1-4, 2-1,... 3-2, 3-3.

[0053] Figure 5 Among them, 1-1, 1-4, 3-1, and 3-4 are the first images, and the remaining images are the second images.

[0054] In an embodiment of the present invention, according to the shooting trajectory and the size of the partial wafer photo, the overlapping pixels of adjacent partial wafer photos can be obtained. At this time, first obtain the point distance between adjacent shooting points in the shooting trajectory; according to the point distance and the size of the partial wafer photo, obtain the overlapping pixels.

[0055] If the shooting point is located at the center of the partial wafer photo, then it can be calculated by the following formula: Overlapping pixels on the X axis = Size of the partial wafer photo on the X axis - Point distance on the X axis between adjacent shooting points.

[0056] Overlapping pixels on the Y axis = Size of the partial wafer photo on the Y axis - Point distance on the Y axis between adjacent shooting points.

[0057] For example, the point distance is 20 pixels, the size of the local wafer photo is 30*30, and the overlapping pixels on the X-axis and Y-axis are both 10.

[0058] In the embodiment of the present invention, the shooting point refers to the actual position when the camera shoots. Generally, it can be considered that the shooting point is at the center position of the local wafer photo, and this position is used as the shooting position.

[0059] Before shooting with a small field of view, the origin of the small field of view coordinates can be determined. For example, the shooting position corresponding to the shooting point of the starting local wafer photo can be used as the origin. Then, knowing the pixels between adjacent shooting points, the point coordinates of each shooting point in the small field of view coordinate system can be obtained.

[0060] In an embodiment of the present invention, assume that the center of the camera's field of view when the camera takes the first shooting point is the origin, and the X-axis and Y-axis are both in pixels. The size of the camera's field of view, that is, each local wafer photo, is 30*30. The adjacent camera shooting points on the X-axis are 20 apart, and the adjacent two camera shooting points on the Y-axis are also 20 apart. Taking the center of the camera's field of view 1-1 as the origin of the coordinate axis, that is, the shooting point is the center of the local wafer photo 1-1. Then, the coordinate range of 1-1 is counted by four points as (-15, 15), (15, 15), (15, -15), (-15, -15).

[0061] The center coordinates of the local wafer photo 1-2 are (20, 0), and the coordinate range is (5, 15), (35, 15), (35, -15), (5, -15).

[0062] The center coordinates of the local wafer photo 2-1 are (0, -20), and the coordinate range is (-15, -5), (15, -5), (15, -35), (-15, -35).

[0063] According to the coordinate range of the local wafer photo, the shooting trajectory, and the overlapping pixels, the coordinate range of the complete wafer photo can be obtained.

[0064] The seg position can actually indicate the order during image stitching. For example, 1-2 is on the right side of 1-1, and 2-1 is below 1-1. Through the seg position and the overlapping pixels, the image stitching can be realized more conveniently and quickly.

[0065] In the embodiment of the present invention, multiple local wafer pictures are stitched into a stitched image including the target die, and the complete picture of the target die is segmented from the stitched image including the target die.

[0066] In one embodiment of the present invention, after obtaining the splicing sequence of each local wafer from the seg, when splicing 1-1 and 2-1, only need to move 2-1 upward by 10 overlapping pixels to directly splice. Similarly, when splicing 1-1 and 1-2, only need to move 1-2 toward 1-1 by 10 to directly splice.

[0067] Figure 8 The following shows the splicing image including the target die according to the embodiment of the present invention. Figure 9 The following shows the schematic diagram of the complete die map after splicing according to the embodiment of the present invention.

[0068] From Figure 8 it can be seen that in addition to including a complete die map, the splicing image also includes parts of other dies around. Therefore, in the embodiment of the present invention, it is also necessary to segment the complete map of the target die from the splicing image. The complete die map obtained after segmentation is as shown in Figure 9 the following.

[0069] To segment the complete map of the target die from the splicing image, it can be segmented according to the coordinates of the segmentation points. For example, use the connection lines between multiple segmentation points as the segmentation lines for segmentation; or a method combining segmentation points and image recognition can be adopted. As shown in Figure 8 the following, there is a large black area near the segmentation points, and segmentation can be performed through the segmentation points and the recognized large black area; or other methods can be adopted, which will not be elaborated here.

[0070] In the embodiment of the present invention Figure 8 as shown in the following, the background color is black, so the large area near the segmentation points is black. In other embodiments of the present invention, if the background color is other colors, then the large area near the segmentation points is the corresponding background color.

[0071] Through the segmentation by segmentation points and / or large pure color background areas, image recognition is relatively simple and fast.

[0072] In the embodiment of the present invention, after segmenting the complete map of the target die from the splicing image including the target die, the method further includes: Obtaining the conversion parameters from the small field-of-view coordinate system to the large field-of-view coordinate system according to the lens magnification, the scaling factor of sampling, and the pixel accuracy; Obtaining the position of the complete map of the target die in the complete wafer photo according to the conversion parameters; wherein, the lens magnification is the lens magnification from the large field-of-view to the small field-of-view.

[0073] In the embodiments of the present invention, in subsequent inspections, if it is detected that a certain complete die is defective or damaged, it is necessary to locate it in the complete wafer photo to pick it out. Therefore, in the embodiments of the present invention, it is also necessary to obtain the position of each complete die diagram in the complete wafer photo.

[0074] The complete wafer photo uses a large-field coordinate system, while the small-field coordinate system is used during splicing. Therefore, it is necessary to obtain the conversion parameters between the large-field coordinate system and the small-field coordinate system.

[0075] In the embodiments of the present invention, in order to obtain a high-definition complete die diagram for subsequent inspections, large-field photography is used, which can obtain a clear die diagram. In the embodiments of the present invention, when splicing local wafer photos into a complete die diagram, splicing is performed according to overlapping pixels without the need for image recognition, and image recognition consumes a long time and computing and storage resources. Therefore, the embodiments of the present invention can save system resources and speed up the image splicing process. In the embodiments of the present invention, before performing a complete die inspection, the complete die diagram is segmented from the spliced image. Refer to Figure 8 、 Figure 9 As shown, the area of the image to be inspected can be greatly reduced, thereby saving system resources once again.

[0076] As Figure 10 shown, the present invention also provides a post-cut wafer inspection device, and the device includes: A photographing unit 810 for performing large-field photography to obtain a complete wafer photo; A separation point acquisition unit 820 for acquiring separation points between a plurality of dies formed by cutting the wafer according to the complete wafer photo; A trajectory acquisition unit 830 for acquiring a photographing trajectory according to the separation points; The photographing unit 810 is further configured to perform small-field photography according to the photographing trajectory to obtain a plurality of local wafer photos; A splicing unit 840 for acquiring the die to which each local wafer photo belongs according to the photographing trajectory; The splicing unit 840 is further configured to splice the local wafer photos belonging to the target die into a spliced image including the target die according to the photographing trajectory and the overlapping pixels; The splicing unit 840 is further configured to segment the complete target die diagram from the spliced image including the target die to inspect the post-cut wafer; wherein the size of each local wafer photo is smaller than the size of a complete die.

[0077] In an embodiment of the present invention, the trajectory acquisition unit 830 is further configured to: Obtain the distance between every two adjacent separation points as a first distance; Obtain the maximum value among all the first distances as a second distance; Obtain a shooting trajectory according to the second distance and the local wafer photo size.

[0078] In an embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points, The trajectory acquisition unit 830 is further configured to: Obtain the number of shooting images between every two adjacent separation points according to the second distance and the local wafer photo size; Obtain shooting points according to the number of shooting images; Plan a scanning path according to the shooting points; Wherein, the number of shooting images includes the number of shooting images on the X-axis and the number of shooting images on the Y-axis, and the scanning path is the sequence of multiple shooting points.

[0079] In an embodiment of the present invention, the splicing unit 840 is further configured to: Obtain the die to which each local wafer photo belongs according to the separation points and the shooting trajectory.

[0080] In an embodiment of the present invention, the splicing unit 840 is further configured to: Obtain the point distance between adjacent shooting points in the shooting trajectory; Obtain the overlapping pixels according to the point distance and the size of the local wafer photo; Wherein, the overlapping pixels include the overlapping pixels on the X-axis and the overlapping pixels on the Y-axis.

[0081] In an embodiment of the present invention, the splicing unit 840 is further configured to: Obtain the position of the shooting point in the local wafer photo as a shooting position; Obtain the point coordinates of each shooting point in the small field-of-view coordinate system according to the shooting trajectory and the shooting position; Obtain the coordinate range of each local wafer photo according to the local wafer photo size, the point coordinates and the shooting position; Obtain the coordinate range of the complete die map according to the coordinate range of the local wafer photo, the shooting trajectory and the overlapping pixels; Obtain the seg position according to the coordinate range of the local wafer photo and the coordinate range of the complete die map; According to the seg position, splice the partial wafer photos belonging to the target die into a spliced image including the target die; Wherein, the seg position is used to indicate the position of a partial die area in the partial wafer photo relative to the complete die diagram.

[0082] The device according to an embodiment of the present invention further includes a positioning unit for: Obtain conversion parameters from the small field-of-view coordinate system to the large field-of-view coordinate system according to the lens magnification, the sampling scaling factor, and the pixel accuracy; Obtain the position of the complete diagram of the target die in the complete wafer photo according to the conversion parameters; Wherein, the lens magnification is the lens magnification from the large field of view to the small field of view.

[0083] The embodiment of the present invention can save a large amount of image recognition processes, improve the splicing speed, save system resources, and reduce costs.

[0084] The embodiment of the present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the following method is implemented: Take a large field of view to obtain a complete wafer photo; According to the complete wafer photo, obtain the separation points between multiple dies formed by wafer dicing; According to the separation points, obtain the shooting trajectory; According to the shooting trajectory, take a small field of view to obtain multiple partial wafer photos; According to the shooting trajectory, obtain the die to which each partial wafer photo belongs; According to the shooting trajectory and the size of the partial wafer photo, obtain the overlapping pixels of adjacent partial wafer photos; According to the shooting trajectory and the overlapping pixels, splice the partial wafer photos belonging to the target die into a spliced image including the target die; Segment the complete diagram of the target die from the spliced image including the target die to detect the diced wafer; Wherein, the size of each partial wafer photo is smaller than the size of a complete die.

[0085] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following method is implemented: performing large-field shooting to obtain a complete wafer photo; obtaining separation points between multiple dies formed by cutting the wafer according to the complete wafer photo; obtaining a shooting trajectory according to the separation points; performing small-field shooting according to the shooting trajectory to obtain multiple local wafer photos; obtaining the die to which each local wafer photo belongs according to the shooting trajectory; obtaining overlapping pixels of adjacent local wafer photos according to the shooting trajectory and the size of the local wafer photos; splicing the local wafer photos belonging to a target die into a spliced image including the target die according to the shooting trajectory and the overlapping pixels; segmenting a complete image of the target die from the spliced image including the target die to detect the cut wafer; wherein the size of each local wafer photo is smaller than the size of a complete die.

[0086] The above method for detecting a cut wafer achieves the beneficial effect of being able to solve the technical problems proposed in the background art.

[0087] Figure 2 It is a schematic flowchart of a method for detecting a cut wafer in an embodiment. It should be understood that although Figure 2 the steps in the flowchart are shown sequentially according to the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise clearly stated in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, Figure 2 at least a part of the steps in

[0088] Figure 11 show the internal structure diagram of a computer device in an embodiment. The computer device may specifically be Figure 1 the server 120 in Figure 11As shown, the computer device includes a processor, a memory, a network interface, an input device, and a display screen connected via a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the method for detecting a diced wafer. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute the method for detecting a diced wafer. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covering the display screen, or a button, trackball, or touchpad provided on the housing of the computer device, or an external keyboard, touchpad, or mouse, etc.

[0089] Those skilled in the art can understand that Figure 11 the structure shown in

[0090] is only a block diagram of some structures related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0091] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0092] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for detecting a wafer after cutting, characterized in that, The method includes: Performing large - field shooting to obtain a complete wafer photo; According to the complete wafer photo, obtaining the separation points between multiple dies formed by cutting the wafer; According to the separation points, obtaining a shooting trajectory; According to the shooting trajectory, performing small - field shooting to obtain multiple local wafer photos; According to the shooting trajectory, obtaining the die to which each local wafer photo belongs; According to the shooting trajectory and the size of the local wafer photo, obtaining the overlapping pixels of adjacent local wafer photos; According to the shooting trajectory and the overlapping pixels, splicing the local wafer photos belonging to the target die into a spliced image including the target die; Segmenting a complete target die map from the spliced image including the target die to detect the cut wafer; Wherein, the size of each local wafer photo is smaller than the size of a complete die.

2. The method according to claim 1, wherein The obtaining the shooting trajectory according to the separation points includes: Obtaining the distance between every two adjacent separation points as a first distance; Obtaining the maximum value among all the first distances as a second distance; According to the second distance and the local wafer photo size, obtaining the shooting trajectory.

3. The method according to claim 2, wherein The shooting trajectory includes a scanning path and shooting points, The obtaining the shooting trajectory according to the second distance and the local wafer photo size includes: According to the second distance and the local wafer photo size, obtaining the number of shooting times between every two adjacent separation points; According to the number of shooting times, obtaining the shooting points; According to the shooting points, planning the scanning path; Wherein, the number of shooting times includes the number of shooting times on the X - axis and the number of shooting times on the Y - axis, and the scanning path is the sequence of multiple shooting points.

4. The method according to claim 3, characterized in that, The obtaining the overlapping pixels of adjacent local wafer photos according to the shooting trajectory and the size of the local wafer photo includes: Obtaining the point - to - point distance between adjacent shooting points in the shooting trajectory; According to the point - to - point distance and the size of the local wafer photo, obtaining the overlapping pixels; Wherein, the overlapping pixels include overlapping pixels on the X - axis and overlapping pixels on the Y - axis.

5. The method according to claim 4, characterized in that, The splicing the local wafer photos belonging to the target die into a spliced image including the target die according to the shooting trajectory and the overlapping pixels includes: Obtaining the position of the shooting point in the local wafer photo as the shooting position; According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in the small - field coordinate system; According to the local wafer photo size, the point coordinates and the shooting position, obtaining the coordinate range of each local wafer photo; According to the coordinate range of the local wafer photo, the shooting trajectory and the overlapping pixels, obtaining the coordinate range of the complete die map; According to the coordinate range of the local wafer photo and the coordinate range of the complete die map, obtaining the divided area position; According to the divided area position, splicing the local wafer photos belonging to the target die into a spliced image including the target die; Wherein, the position of the divided area is used to indicate the position of a partial die area in the partial wafer photo relative to the complete die map.

6. The method according to claim 1, wherein After segmenting the complete map of the target die from the stitched image including the target die, the method further includes: Obtaining conversion parameters from the small field-of-view coordinate system to the large field-of-view coordinate system according to the lens magnification, the sampling scaling factor, and the pixel accuracy; Obtaining the position of the complete map of the target die in the complete wafer photo according to the conversion parameters; Wherein, the lens magnification is the lens magnification from the large field-of-view to the small field-of-view.

7. A wafer inspection device after cutting, characterized in that, The apparatus includes: A photographing unit, configured to perform photographing with a large field-of-view to obtain a complete wafer photo; A dividing point obtaining unit, configured to obtain dividing points between a plurality of dies formed by wafer cutting according to the complete wafer photo; A trajectory obtaining unit, configured to obtain a photographing trajectory according to the dividing points; The photographing unit is further configured to perform photographing with a small field-of-view according to the photographing trajectory to obtain a plurality of partial wafer photos; A stitching unit, configured to obtain the die to which each partial wafer photo belongs according to the photographing trajectory; The stitching unit is further configured to obtain overlapping pixels of adjacent partial wafer photos according to the photographing trajectory and the size of the partial wafer photos; The stitching unit is further configured to stitch the partial wafer photos belonging to the target die into a stitched image including the target die according to the photographing trajectory and the overlapping pixels; The stitching unit is further configured to segment a complete map of the target die from the stitched image including the target die for inspecting the cut wafer; Wherein, the size of each partial wafer photo is smaller than the size of a complete die.

8. The device according to claim 7, wherein The stitching unit is further configured to: Obtain the position of the photographing point in the partial wafer photo as the photographing position; Obtain the point coordinates of each photographing point in the small field-of-view coordinate system according to the photographing trajectory and the photographing position; Obtain the coordinate range of each partial wafer photo according to the size of the partial wafer photo, the point coordinates, and the photographing position; Obtain the coordinate range of the complete die map according to the coordinate range of the partial wafer photo, the photographing trajectory, and the overlapping pixels; Obtain the position of the divided area according to the coordinate range of the partial wafer photo and the coordinate range of the complete die map; Stitch the partial wafer photos belonging to the target die into a stitched image including the target die according to the position of the divided area; Wherein, the position of the divided area is used to indicate the position of a partial die area in the partial wafer photo relative to the complete die map.

9. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the method according to any one of claims 1 to 6 is implemented.

Images