Method, device, computer equipment and storage medium for detecting wafers after dicing

Abstract

The present invention relates to a post-cut wafer inspection method, apparatus, computer equipment, and storage medium. The method comprises: using a wide field of view to photograph a complete wafer; obtaining separation points between multiple dies cut from the wafer based on the complete wafer photograph; obtaining a shooting trajectory based on the separation points; using a small field of view to photograph a plurality of partial wafer photos based on the shooting trajectory; obtaining the die to which each partial wafer photo belongs based on the shooting trajectory; obtaining overlapping pixels of adjacent partial wafer photos based on the shooting trajectory and the size of the partial wafer photos; splicing the partial wafer photos belonging to a target die into a spliced ​​image containing the target die based on the shooting trajectory and the overlapping pixels; and segmenting a complete target die image from the spliced ​​image containing the target die to inspect the wafer after cutting. The present invention can splice partial wafer photos into a complete die image and save resources.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and in particular to a method, device, computer equipment and storage medium for detecting wafers after dicing. Background Art

[0002] A wafer is the silicon wafer used to manufacture silicon semiconductor circuits. Wafer scribing, also known as wafer dicing, refers to the process of cutting a single wafer into multiple independent chips, integrated circuits, wafers, or dies. The chips, integrated circuits, wafers, or dies cut from a wafer are also called dies. Mainstream wafer scribing methods include mechanical scribing and laser scribing.

[0003] Whether mechanical or laser scribing, there's a risk of damage to the edges, corners, or even other areas of the die, resulting in defective products. Therefore, after wafer dicing, a high-definition camera is needed to inspect the die for quality. To better verify the integrity of the diced chips, high-definition cameras offer high clarity but a narrow field of view, so multiple images of a single die are typically taken and stitched together for inspection.

[0004] In the prior art, during wafer processing and dicing, a blue film is applied to one or both sides of the wafer to protect the wafer and chips. After the wafer is cut, the blue film deforms irregularly, resulting in irregular arrangement of the cut chips. The prior art inspection method to address this irregular arrangement of cut chips is to increase the shooting range of the high-definition camera, that is, to take more photos of each cut chip. This requires more storage and computing resources to be consumed during the inspection process, resulting in 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 wafers after dicing.

[0006] In a first aspect, the present invention provides a method for detecting wafers after dicing, the method comprising:

[0007] Use a wide field of view to capture a full wafer image;

[0008] Obtaining separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0009] According to the separation points, obtaining a shooting trajectory;

[0010] According to the shooting trajectory, a small field of view is used to shoot to obtain multiple local wafer photos;

[0011] According to the shooting trajectory, obtaining the die to which each of the partial wafer photos belongs;

[0012] Acquire overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos;

[0013] 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;

[0014] Segmenting a complete image of the target die from the stitched image containing the target die to inspect the cut wafer;

[0015] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0016] Optionally, obtaining a shooting trajectory according to the separation point includes:

[0017] Obtaining the distance between every two adjacent separation points as a first distance;

[0018] Obtaining the maximum value of all the first distances as the second distance;

[0019] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0020] Optionally, the shooting trajectory includes a scanning path and shooting points.

[0021] The acquiring of the shooting trajectory according to the second distance and the size of the local wafer photograph includes:

[0022] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0023] Obtaining shooting points according to the number of shots;

[0024] Planning a scanning path according to the shooting points;

[0025] The number of shots includes the number of shots along the X-axis and the number of shots along the Y-axis, and the scanning path is the sequence of multiple shooting points.

[0026] Optionally, obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes:

[0027] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0028] Acquire the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0029] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0030] Optionally, stitching the partial wafer photos belonging to the target die into a stitched image including the target die according to the shooting trajectory and the overlapping pixels, including:

[0031] Obtaining a position of the shooting point in the partial wafer photograph as a shooting position;

[0032] According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system;

[0033] Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position;

[0034] Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels;

[0035] Obtaining a location of a divided area according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map;

[0036] splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the divided area positions;

[0037] The divided area position is used to indicate the position of the partial die area in the local wafer photo relative to the complete die image.

[0038] Optionally, after segmenting the complete image of the target die from the stitched image containing the target die, the method further includes:

[0039] Obtain the conversion parameters from the small field of view coordinate system to the large field of view coordinate system based on the lens magnification, sampling scaling factor and pixel accuracy;

[0040] Obtaining a position of the target die complete image in the complete wafer photograph according to the conversion parameters;

[0041] The lens magnification is the lens magnification from the large field of view to the small field of view.

[0042] In a second aspect, a post-cut wafer inspection device is provided, the device comprising:

[0043] A shooting unit, used for shooting with a large field of view to obtain a complete wafer photo;

[0044] a separation point acquisition unit, which acquires separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0045] A trajectory acquisition unit, configured to acquire a shooting trajectory according to the separation points;

[0046] The shooting unit is further configured to capture multiple local wafer photos using a small field of view according to the shooting trajectory;

[0047] a stitching unit, configured to obtain the die to which each of the partial wafer photos belongs according to the shooting trajectory;

[0048] The stitching unit is further configured to obtain overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos;

[0049] 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 shooting trajectory and the overlapping pixels;

[0050] The stitching unit is further configured to segment a complete image of the target die from the stitched image containing the target die, so as to inspect the cut wafer;

[0051] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0052] Optionally, the splicing unit is further used for:

[0053] Obtaining a position of the shooting point in the partial wafer photograph as a shooting position;

[0054] According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system;

[0055] Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position;

[0056] Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels;

[0057] Obtaining a location of a divided area according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map;

[0058] splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the divided area positions;

[0059] The divided area position is used to indicate the position of the partial die area in the local wafer photo relative to the complete die image.

[0060] In a third aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the above methods when executing the computer program.

[0061] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the method as described in any one of the above items is implemented.

[0062] The present invention provides a post-cut wafer inspection method, apparatus, computer equipment, and storage medium. The method comprises: using a wide field of view to obtain a complete wafer photograph; obtaining the separation points between multiple dies cut from the wafer based on the complete wafer photograph; obtaining a shooting trajectory based on the separation points; using a small field of view to obtain multiple partial wafer photographs based on the shooting trajectory; obtaining the die to which each partial wafer photograph belongs based on the shooting trajectory; obtaining overlapping pixels of adjacent partial wafer photographs based on the shooting trajectory and the size of the partial wafer photographs; splicing the partial wafer photographs belonging to the target die into a spliced ​​image containing the target die based on the shooting trajectory and the overlapping pixels; segmenting the complete target die image from the spliced ​​image containing the target die to inspect the wafer after cutting; wherein the size of each partial wafer photograph is smaller than the size of a complete die. In the method of an embodiment of the present invention, a wide field of view is first used to obtain a complete wafer photograph; obtaining the separation points between multiple dies cut from the wafer based on the complete wafer photograph; and then switching to a small field of view to obtain multiple partial wafer photographs. When taking photos in a small field of view, the images are taken according to the shooting trajectory. The die to which each partial wafer photo belongs is determined, and overlapping pixels are obtained. Then, stitching is performed based on the shooting trajectory and overlapping pixels, and the complete image of the target die is segmented from the stitched image. Compared to methods that identify overlapping areas through image stitching, the method of the embodiment of the present invention directly stitches through overlapping pixels, which can save a lot of image recognition processes, improve stitching speed, save system resources, and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0064] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0065] Figure 1 FIG2 is a diagram showing an application environment of a method for detecting wafers after dicing according to an embodiment of the present invention;

[0066] Figure 2 FIG2 is a flow chart of a method for inspecting wafers after dicing according to an embodiment of the present invention;

[0067] Figure 3 Shown is a schematic diagram of a complete wafer photograph according to an embodiment of the present invention;

[0068] Figure 4 Shown is a schematic diagram of a partially enlarged photograph of a complete wafer according to an embodiment of the present invention;

[0069] Figure 5 Shown is a schematic diagram of multiple partial wafer photos according to an embodiment of the present invention;

[0070] Figure 6 FIG2 is a schematic diagram of a scanning path according to an embodiment of the present invention;

[0071] Figure 7 FIG2 is a schematic diagram of a scanning path according to an embodiment of the present invention;

[0072] Figure 8 Shown is a spliced ​​image containing the target die according to an embodiment of the present invention;

[0073] Figure 9 FIG2 is a schematic diagram of a complete die image after splicing according to an embodiment of the present invention;

[0074] Figure 10 Schematic diagram of a wafer inspection device after dicing according to an embodiment of the present invention;

[0075] Figure 11 FIG. 1 is a diagram showing the internal structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0076] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0077] Figure 1 FIG2 is an application environment diagram of the wafer inspection method after cutting according to an embodiment of the present invention. Figure 1 The post-cut wafer inspection method is applied to a post-cut wafer inspection system. The post-cut wafer inspection method includes a terminal 110 and / or a server 120. Terminal 110 and server 120 are connected via a network. Terminal 110 can be a desktop terminal or a mobile terminal. The mobile terminal can be at least one of a mobile phone, a tablet computer, and a laptop computer. Server 120 can be implemented as a standalone server or a server cluster consisting of multiple servers.

[0078] The post-cut wafer detection method of the present invention is applied to the terminal 110 and / or the server 120 .

[0079] Figure 2 FIG. 1 is a flow chart of a method for inspecting wafers after dicing according to an embodiment of the present invention. Figure 2 As shown, the method includes:

[0080] Step 210 , photographing with a wide field of view to obtain a complete wafer photograph;

[0081] Step 220 , obtaining separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0082] Step 230: obtaining a shooting trajectory according to the separation point;

[0083] Step 240 , taking a plurality of local wafer photos using a small field of view according to the shooting trajectory;

[0084] Step 250 , obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory;

[0085] Step 260 , obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos;

[0086] Step 270 , stitching the partial wafer photos belonging to the target die into a stitched image including the target die based on the shooting trajectory and the overlapping pixels;

[0087] Step 280 : Segment a complete image of the target die from the stitched image containing the target die to inspect the cut wafer.

[0088] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0089] Large and small FOV images can be taken with the same camera at different focal lengths, or with different cameras. Whether the camera is the same or different, calibration and / or testing are required before testing to confirm the conversion parameters from large to small FOV.

[0090] Transformation parameters can include factors such as lens magnification, sampling scaling factor, and pixel accuracy. Transformation parameters can be used to transform coordinate systems. For example, the coordinates of a point in a large FOV coordinate system can be transformed into coordinates in a small FOV coordinate system using the transformation parameters. Similarly, coordinates in a small FOV coordinate system can be transformed into coordinates in a large FOV coordinate system by transposing the transformation parameters.

[0091] The separation point in the embodiment of the present invention refers to the point where the boundaries of different dies intersect after the wafer is cut.

[0092] Figure 3 FIG. 1 is a schematic diagram of a complete wafer photograph of an embodiment of the present invention. Figure 3 In the image processing, due to the large field of view, each die in the wafer is relatively small and the pixel density is low, which is not convenient for subsequent detection.

[0093] Figure 3 In the figure, each green box can be considered as a cut die. The intersection of the green lines can be used as the separation point.

[0094] Figure 4 FIG. 1 is a schematic diagram showing a magnified portion of a complete wafer photograph according to an embodiment of the present invention. Figure 4 As shown, the separation point 410 can be considered to be the center of the cross. Figure 4 There are multiple separation points in the , only one is marked.

[0095] Wide-field imaging allows for a wider field of view, allowing for complete wafer image capture. However, this results in lower precision and clarity, making it difficult to distinguish and subsequently inspect. Small-field imaging offers high precision and clarity, and can be used to detect damaged dies after wafer dicing. To ensure high clarity and precision, small-field imaging makes it difficult to capture a complete die, so multiple partial wafer images must be stitched together to create a complete die image.

[0096] In the method of the embodiment of the present invention, a wide field of view is first used to shoot to obtain a complete wafer photo; based on the complete wafer photo, the separation points between the multiple dies cut from the wafer are obtained; and then the shooting is converted to a small field of view to obtain multiple partial wafer photos. When taking photos with a small field of view, the shooting is performed according to the shooting trajectory, and then the die to which each of the partial wafer photos belongs is determined, and overlapping pixels are obtained, and then splicing is performed according to the shooting trajectory and overlapping pixels, and the complete image of the target die is segmented from the spliced ​​image. Compared with the method of identifying overlapping areas through images and then performing splicing, the method of the embodiment of the present invention directly performs splicing through overlapping pixels, which can save a lot of image recognition processes, can increase the splicing speed, and can also save system resources and reduce costs.

[0097] In the embodiment of the present invention, step 230, obtaining the shooting trajectory according to the separation point, includes:

[0098] Obtaining the distance between every two adjacent separation points as a first distance;

[0099] Obtaining the maximum value of all the first distances as the second distance;

[0100] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0101] refer to Figure 3 、 Figure 4 As shown, the separation points are actually the points where the boundaries of 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.

[0102] Taking into account the clarity of the complete wafer photo and other errors in the selection of the separation points, the method of the embodiment of the present invention obtains the shooting trajectory according to the maximum distance between the separation points, which can reduce subsequent errors.

[0103] The size of a local wafer photo is usually rectangular or positive, you can refer to Figure 5 shown.

[0104] In an embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points.

[0105] The acquiring of the shooting trajectory according to the second distance and the size of the local wafer photograph includes:

[0106] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0107] Obtaining shooting points according to the number of shots;

[0108] Planning a scanning path according to the shooting points;

[0109] The number of shots includes the number of shots along the X-axis and the number of shots along the Y-axis, and the scanning path is the sequence of multiple shooting points.

[0110] The number of X-axis shots can be calculated by dividing the second X-axis distance by the X-axis size of the local wafer photo, rounding up, and adding 1 or 2.

[0111] Rounding up is to ensure a certain margin and overlapping pixels, and adding 1 or 2 is to make the separation point in the local wafer photo located at the center of the field of view or near the center of the field of view.

[0112] In one embodiment of the present invention, assuming that the second distance along the X axis is 80 and the second distance along the Y axis is 60, the size of the local wafer photo may be 30 along the X axis and 30 along the Y axis. In this case, it can be calculated that 4 or 5 photos are taken along the X axis and 3 or 4 photos are taken along the Y axis.

[0113] In fact, the principle for obtaining the number of shots is that multiple local wafer photos can cover the entire die and there is a certain overlap between them.

[0114] In the embodiment of the present invention, the scanning path can be arranged in rows or columns. When arranged in rows, the scanning path can be unidirectional along the X-axis or bidirectional along the X-axis. Figure 6 FIG. 1 is a schematic diagram of a scanning path according to an embodiment of the present invention. According to row scanning, the scanning path is from point C1 along the positive direction of the X axis to point C2, back to the shooting point C3 of another row, and then along the positive direction of the X axis to C4.

[0115] Figure 7 FIG. 1 is a schematic diagram of a scanning path according to an embodiment of the present invention. According to row scanning, the scanning path is from point C1 along the positive direction of the X axis to point C2, then moves down to the shooting point C4 of another row, and then moves back along the X axis to C3.

[0116] In the embodiment of the present invention, the distance between two adjacent shooting points can be equidistant or unequal. When the distance is unequal, the distance between each two adjacent shooting points needs to be recorded separately.

[0117] In the embodiment of the present invention, the distance between two adjacent shooting points is preferably equidistant.

[0118] In an embodiment of the present invention, in step 250, obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory includes:

[0119] The die to which each of the partial wafer photos belongs is obtained according to the separation points and the shooting trajectory.

[0120] like Figure 4 、 Figure 5 、 Figure 6 As shown, if according to Figure 6 The shooting trajectory is from C1 to C2, then the local wafer photos from the first separation point along the X axis to the other separation point belong to the same die. Figure 5 , 1-1, 1-2, 1-3 and 1-4 are several partial wafer photos between two separation points, belonging to the same die, recorded as diaA. Of course, refer to Figure 5 As shown, parts of these partial wafer photos belong to die A, while other parts may belong to different dies. For example, the lower right portion of 1-1, the lower half of 1-2, the lower half of 1-3, and the lower left portion of 1-4 all belong to die A, while the upper left, lower left, and upper right portions of 1-1 belong to four different dies. Similarly, the upper half of 1-2 also belongs to another die.

[0121] Reference Figure 6 According to the shooting trajectory, the X-axis and Y-axis coordinates, the Y-axis coordinates of the center coordinates of 1-1 and the center coordinates of 2-1 are the same, and 2-1 is the next row of 1-1 and has no separation point, so it can be confirmed that 2-1 belongs to dieA. Similarly, according to the coordinates and shooting trajectory, it can be confirmed that 2-1, 2-3, and 2-4 belong to dieA, and 3-1 and 3-4 have a separation point, so it can be confirmed that 3-1, 3-2, 3-3, and 3-4 also belong to dieA.

[0122] In an embodiment of the present invention, obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes:

[0123] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0124] Acquire the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0125] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0126] In an embodiment of the present invention, in step 270, stitching the partial wafer photos belonging to the target die into a stitched image including the target die according to the shooting trajectory and the overlapping pixels includes:

[0127] Obtaining a position of the shooting point in the partial wafer photograph as a shooting position;

[0128] According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system;

[0129] Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position;

[0130] Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels;

[0131] Obtaining a location of a divided area according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map;

[0132] splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the divided area positions;

[0133] The divided area position is used to indicate the position of the partial die area in the local wafer photo relative to the complete die image.

[0134] In the embodiment of the present invention, “divided area” may also be expressed as seg.

[0135] Figure 5 Shown is a schematic diagram of multiple local wafer photos according to an embodiment of the present invention. For ease of description, the multiple local wafer photos are numbered from left to right and from top to bottom as 1-1, 1-2, 1-3, 1-4, 2-1, ... 3-2, 3-3.

[0136] Figure 5 , 1-1, 1-4, 3-1 and 3-4 are first images, and the remaining images are second images.

[0137] In an embodiment of the present invention, based on the shooting trajectory and the size of the local wafer photo, the overlapping pixels of adjacent local wafer photos can be obtained. At this time, the point distance between adjacent shooting points in the shooting trajectory is first obtained; based on the point distance and the size of the local wafer photo, the overlapping pixels are obtained.

[0138] If the shooting point is located at the center of the local wafer photo, it can be calculated by the following formula:

[0139] X-axis overlap pixels = X-axis size of the local wafer photo - X-axis point distance between adjacent shooting points.

[0140] Y-axis overlap pixels = Y-axis size of the local wafer photo - Y-axis point distance between adjacent shooting points.

[0141] For example, the point distance is 20 pixels, the size of the local wafer photo is 30*30, and the X-axis and Y-axis overlap pixels are both 10.

[0142] In the embodiment of the present invention, the shooting point refers to the actual position of the camera when shooting. Generally, the shooting point can be considered to be the center position in the local wafer photo, and this position is used as the shooting position.

[0143] Before shooting in a small field of view, the origin of a small field of view coordinate system can be determined. For example, the shooting position corresponding to the shooting point where the initial local wafer photo is taken can be used as the origin. Then, by knowing the pixels between adjacent shooting points, the point coordinates of each shooting point in the small field of view coordinate system can be known.

[0144] In one embodiment of the present invention, the center of the camera's field of view, taken at the first camera point, is assumed to be the origin, and both the X- and Y-coordinate axes are measured in pixels. Assuming the camera field of view, i.e., each partial wafer photo, is 30*30 pixels in size, the distance between adjacent camera points on the X-axis is 20 pixels, and the distance between adjacent camera points on the Y-axis is also 20 pixels. With the center of the camera's field of view at 1-1 as the origin of the coordinate axes, i.e., the photo point is the center of partial wafer photo 1-1, then the 1-1 coordinate range, calculated using four points, is (-15, 15), (15, 15), (15, -15), and (-15, -15).

[0145] The center coordinates of the partial wafer photo 1-2 are (20, 0), and the coordinate ranges are (5, 15), (35, 15), (35, -15), and (5, -15).

[0146] The center coordinates of the partial wafer photograph 2-1 are (0, -20), and the coordinate range is (-15, -5), (15, -5), (15, -35), (-15, -35).

[0147] Based on the coordinate range of the partial wafer photo, the shooting trajectory, and overlapping pixels, the coordinate range of the complete wafer photo can be obtained.

[0148] The seg position actually indicates the order in which images are stitched together, for example, 1-2 is to the right of 1-1, and 2-1 is below 1-1. By using the seg position and overlapping pixels, image stitching can be achieved more conveniently and quickly.

[0149] In an embodiment of the present invention, a plurality of partial wafer images are stitched together into a stitched image including the target die, and a complete image of the target die is segmented from the stitched image including the target die.

[0150] In one embodiment of the present invention, after obtaining the splicing order of each local wafer with seg, when splicing 1-1 and 2-1, it is only necessary to move 2-1 up by 10 overlapping pixels to directly splice them. Similarly, when splicing 1-1 and 1-2, it is only necessary to move 1-2 toward 1-1 by 10 to directly splice them.

[0151] Figure 8 FIG. 1 shows a spliced ​​image including the target die according to an embodiment of the present invention. Figure 9 FIG. 1 is a schematic diagram of a complete die image after splicing according to an embodiment of the present invention.

[0152] from Figure 8 As can be seen from the figure, the stitched image includes not only a complete die image, but also parts of other dies around it. Therefore, in the embodiment of the present invention, it is necessary to segment the complete image of the target die from the stitched image. The complete die image obtained after segmentation is as follows: Figure 9 shown.

[0153] To segment the complete image of the target die from the spliced ​​image, segmentation can be performed based on the coordinates of the separation points, for example, using the lines between multiple separation points as the segmentation lines; or a combination of separation points and image recognition can be used, as shown in the following example. Figure 8 As shown, there is a larger black area near the separation point, and segmentation can be performed through the separation point and the identified larger black area; or other methods can be used, which will not be described here.

[0154] The present invention Figure 8 In the embodiment shown, the background color is black, so the larger area near the separation point is black. In other embodiments of the present invention, if the background color is other colors, the larger area near each point is the corresponding background color.

[0155] Image recognition is simpler and faster by segmenting the separation points and / or larger solid background areas.

[0156] In the embodiment of the present invention, after segmenting the complete image of the target die from the stitched image containing the target die, the method further includes:

[0157] Obtain the conversion parameters from the small field of view coordinate system to the large field of view coordinate system based on the lens magnification, sampling scaling factor and pixel accuracy;

[0158] Obtaining a position of the target die complete image in the complete wafer photograph according to the conversion parameters;

[0159] The lens magnification is the lens magnification from the large field of view to the small field of view.

[0160] In the embodiment of the present invention, if a complete die is detected to be defective or damaged during subsequent inspection, it needs to be located in the complete wafer photo to be picked out. Therefore, in the embodiment of the present invention, it is also necessary to obtain the position of each complete die image in the complete wafer photo.

[0161] The complete wafer photo uses a large field of view coordinate system, while the stitching uses a small field of view coordinate system. Therefore, it is necessary to obtain the conversion parameters between the large field of view coordinate system and the small field of view coordinate system.

[0162] In the embodiment of the present invention, in order to obtain a high-definition complete die image and facilitate subsequent detection, a wide field of view is used to take pictures, so that a clear die image can be obtained. In the embodiment of the present invention, when stitching partial wafer photos into a complete die image, stitching is performed based on overlapping pixels, without the need for image recognition. Image recognition consumes a long time and computing and storage resources. Therefore, the embodiment of the present invention can save system resources and speed up the image stitching process. In the embodiment of the present invention, before performing a complete die detection, the complete die image is segmented from the stitched image. Figure 8 、 Figure 9 As shown, the area of ​​the image to be detected can be greatly reduced, thereby saving system resources again.

[0163] like Figure 10 As shown, the present invention also provides a post-cut wafer inspection device, the device comprising:

[0164] The photographing unit 810 is used to photograph with a wide field of view to obtain a complete wafer photograph;

[0165] A separation point acquisition unit 820 acquires separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0166] The trajectory acquisition unit 830 is used to acquire the shooting trajectory according to the separation point;

[0167] The photographing unit 810 is further configured to photograph a plurality of local wafer photos using a small field of view according to the photographing trajectory;

[0168] a stitching unit 840 , configured to obtain the die to which each of the partial wafer photos belongs according to the shooting trajectory;

[0169] The stitching unit 840 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 shooting trajectory and the overlapping pixels;

[0170] The stitching unit 840 is further configured to segment a complete image of the target die from the stitched image containing the target die, so as to inspect the cut wafer;

[0171] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0172] In the embodiment of the present invention, the trajectory acquisition unit 830 is further configured to:

[0173] Obtaining the distance between every two adjacent separation points as a first distance;

[0174] Obtaining the maximum value of all the first distances as the second distance;

[0175] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0176] In the embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points.

[0177] The trajectory acquisition unit 830 is further configured to:

[0178] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0179] Obtaining shooting points according to the number of shots;

[0180] Planning a scanning path according to the shooting points;

[0181] The number of shots includes the number of shots along the X-axis and the number of shots along the Y-axis, and the scanning path is the sequence of multiple shooting points.

[0182] In the embodiment of the present invention, the splicing unit 840 is further configured to:

[0183] The die to which each of the partial wafer photos belongs is obtained according to the separation points and the shooting trajectory.

[0184] In the embodiment of the present invention, the splicing unit 840 is further configured to:

[0185] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0186] Obtaining the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0187] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0188] In the embodiment of the present invention, the splicing unit 840 is further configured to:

[0189] Obtaining a position of the shooting point in the partial wafer photograph as a shooting position;

[0190] According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system;

[0191] Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position;

[0192] Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels;

[0193] Obtaining a seg position according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map;

[0194] splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the seg positions;

[0195] The seg position is used to indicate the position of a partial die area in the local wafer photo relative to the complete die image.

[0196] The device according to the embodiment of the present invention further includes a positioning unit, configured to:

[0197] Obtain the conversion parameters from the small field of view coordinate system to the large field of view coordinate system based on the lens magnification, sampling scaling factor and pixel accuracy;

[0198] Obtaining a position of the target die complete image in the complete wafer photograph according to the conversion parameters;

[0199] The lens magnification is the lens magnification from the large field of view to the small field of view.

[0200] The embodiments of the present invention can save a lot of image recognition processes, improve the splicing speed, save system resources and reduce costs.

[0201] An embodiment of the present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following method when executing the computer program: using a large field of view to obtain a complete wafer photo; based on the complete wafer photo, obtaining the separation points between multiple dies cut from the wafer; based on the separation points, obtaining a shooting trajectory; based on the shooting trajectory, using a small field of view to obtain multiple partial wafer photos; based on the shooting trajectory, obtaining the die to which each partial wafer photo belongs; based on the shooting trajectory and the size of the partial wafer photos, obtaining overlapping pixels of adjacent partial wafer photos; based on the shooting trajectory and the overlapping pixels, splicing the partial wafer photos belonging to the target die into a spliced ​​image containing the target die; segmenting the complete image of the target die from the spliced ​​image containing the target die to inspect the cut wafer; wherein the size of each partial wafer photo is smaller than the size of a complete die.

[0202] An embodiment of the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following method: using a large field of view to shoot to obtain a complete wafer photo; based on the complete wafer photo, obtaining the separation points between multiple dies cut from the wafer; based on the separation points, obtaining a shooting trajectory; based on the shooting trajectory, using a small field of view to shoot to obtain multiple partial wafer photos; based on the shooting trajectory, obtaining the die to which each of the partial wafer photos belongs; based on the shooting trajectory and the size of the partial wafer photos, obtaining overlapping pixels of adjacent partial wafer photos; based on the shooting trajectory and the overlapping pixels, splicing the partial wafer photos belonging to the target die into a spliced ​​image containing the target die; segmenting the complete image of the target die from the spliced ​​image containing the target die to inspect the cut wafer; wherein the size of each of the partial wafer photos is smaller than the size of a complete die.

[0203] The above-mentioned method for detecting wafers after dicing achieves the beneficial effect of being able to solve the technical problems raised in the background technology.

[0204] Figure 2 FIG. 1 is a flow chart of a method for detecting wafers after dicing in one embodiment. It should be understood that although Figure 2 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. In addition, Figure 2 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0205] Figure 11 The internal structure diagram of a computer device in one embodiment is shown. The computer device may 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. 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 may implement the post-cut wafer inspection method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor may implement the post-cut wafer inspection method. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the computer device housing, or an external keyboard, touchpad or mouse.

[0206] Those skilled in the art will understand that Figure 11 The structure shown in the figure is merely a block diagram of a portion of the structure 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 shown in the figure, or combine certain components, or have a different component arrangement.

[0207] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When executed, the program can include the processes of the above-described method embodiments. Any reference to memory, storage, database, or other media used in the various embodiments provided herein may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct RAMbus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM).

[0208] It should be noted that, in this document, relational terms such as "first" and "second" are used only 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 terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0209] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for detecting wafers after dicing, characterized in that: The method comprises: Use a wide field of view to capture a full wafer image; Obtaining separation points between a plurality of dies cut from the wafer based on the complete wafer photograph; According to the separation points, obtaining a shooting trajectory; According to the shooting trajectory, a small field of view is used to shoot to obtain multiple local wafer photos; According to the shooting trajectory, obtaining the die to which each of the partial wafer photos belongs; Acquire 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; Segmenting a complete image of the target die from the stitched image containing the target die to inspect the cut wafer; wherein the size of each of the partial wafer photos is smaller than the size of a complete die; The acquiring of the shooting trajectory according to the separation point includes: Obtain the distance between every two adjacent separation points as the first distance, Get the maximum value of all the first distances as the second distance, A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

2. The method according to claim 1, characterized in that The shooting trajectory includes a scanning path and shooting points. The acquiring of the shooting trajectory according to the second distance and the size of the local wafer photograph includes: Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph; Obtaining shooting points according to the number of shots; Planning a scanning path according to the shooting points; The number of shots includes the number of shots along the X-axis and the number of shots along the Y-axis, and the scanning path is the sequence of multiple shooting points.

3. The method according to claim 2, characterized in that The acquiring overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes: Obtaining the 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 photograph; The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

4. The method according to claim 3, characterized in that The step of stitching the partial wafer photos belonging to the target die into a stitched image including the target die according to the shooting trajectory and the overlapping pixels includes: Obtaining a position of the shooting point in the partial wafer photograph as a shooting position; According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system; Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position; Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels; Obtaining a location of a divided area according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map; splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the divided area positions; The divided area position is used to indicate the position of the partial die area in the local wafer photo relative to the complete die image.

5. The method according to claim 1, characterized in that After segmenting the complete image of the target die from the spliced ​​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 based on the lens magnification, sampling scaling factor and pixel accuracy; Obtaining a position of the target die complete image in the complete wafer photograph according to the conversion parameters; The lens magnification is the lens magnification from the large field of view to the small field of view.

6. A wafer inspection device after dicing, characterized in that: The device comprises: A shooting unit, used for shooting with a large field of view to obtain a complete wafer photo; a separation point acquisition unit, which acquires separation points between a plurality of dies cut from the wafer based on the complete wafer photograph; A trajectory acquisition unit, configured to acquire a shooting trajectory according to the separation points; The shooting unit is further configured to capture multiple local wafer photos using a small field of view according to the shooting trajectory; a stitching unit, configured to obtain the die to which each of the partial wafer photos belongs according to the shooting trajectory; The stitching unit is further configured to obtain overlapping pixels of adjacent partial wafer photos according to the shooting 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 shooting trajectory and the overlapping pixels; The stitching unit is further configured to segment a complete image of the target die from the stitched image containing the target die, so as to inspect the cut wafer; wherein the size of each of the partial wafer photos is smaller than the size of a complete die; The trajectory acquisition unit is further configured to: Obtain the distance between every two adjacent separation points as the first distance, Get the maximum value of all the first distances as the second distance, A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

7. The device according to claim 6, characterized in that The splicing unit is also used for: Obtaining a position of the shooting point in the partial wafer photograph as a shooting position; According to the shooting trajectory and the shooting position, obtaining the point coordinates of each shooting point in a small field of view coordinate system; Obtaining a coordinate range of each of the partial wafer photos according to the size of the partial wafer photos, the point coordinates, and the shooting position; Obtaining a coordinate range of a complete die image according to the coordinate range of the partial wafer photograph, the shooting trajectory, and the overlapping pixels; Obtaining a location of a divided area according to a coordinate range of the partial wafer photo and a coordinate range of the complete die map; splicing the partial wafer photos belonging to the target die into a spliced ​​image including the target die according to the divided area positions; The divided area position is used to indicate the position of the partial die area in the local wafer photo relative to the complete die image.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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