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

Abstract

The present invention relates to a post-cut wafer inspection method, device, 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 photo; 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; identifying corner points based on the partial wafer photos; obtaining the die to which each partial wafer photo belongs based on the shooting trajectory and the corner points; segmenting the partial wafer photos based on the die to which each partial wafer photo belongs to obtain segmented photos; obtaining overlapping pixels of adjacent partial wafer photos based on the shooting trajectory and the size of the partial wafer photos; and splicing the segmented photos and partial wafer photos belonging to the target die into a complete image of the target die based on the shooting trajectory and the overlapping pixels. The present invention can splice the partial wafer photos into a complete image of the target die 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 a silicon wafer used to manufacture silicon semiconductor circuits. Wafer scribing, also known as wafer dicing, is the process of cutting a single wafer into multiple individual chips (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 photo;

[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] identifying corner points according to the partial wafer photograph;

[0012] Obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory and the corner points;

[0013] Segmenting the partial wafer photos according to the die to which each partial wafer photo belongs to obtain segmented photos;

[0014] acquiring overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos;

[0015] splicing the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die according to the shooting trajectory and the overlapping pixels, so as to inspect the cut wafer;

[0016] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0017] Optionally, obtaining a shooting trajectory according to the separation point includes:

[0018] Obtaining the distance between every two adjacent separation points as a first distance;

[0019] Obtaining the maximum value of all the first distances as the second distance;

[0020] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0021] Optionally, the shooting trajectory includes a scanning path and shooting points.

[0022] The acquiring of the shooting trajectory according to the second distance and the size of the local wafer photograph includes:

[0023] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0024] Obtaining shooting points according to the number of shots;

[0025] Planning a scanning path according to the shooting points;

[0026] 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.

[0027] Optionally, identifying corner points based on the partial wafer photograph includes:

[0028] Acquire a photo including a separation point from the partial wafer photo as a first image;

[0029] Corner points are identified from the first image according to the recognition template.

[0030] Optionally, obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory and the corner points includes:

[0031] According to the recognition template, obtaining the position type of each corner point;

[0032] Acquire the first image belonging to the same die according to the position type and the shooting trajectory;

[0033] taking the partial wafer photograph excluding the separation point as a second image;

[0034] According to the shooting trajectory, obtaining the die to which each second image belongs;

[0035] The position types include a first type, a second type, a third type, and a fourth type. The same die includes four corner points, and the position types of the four corner points are different.

[0036] Optionally, obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes:

[0037] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0038] Obtaining the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0039] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0040] Optionally, stitching the segmented photos belonging to the target die and the local wafer photos belonging to the target die into a complete image of the target die according to the shooting trajectory and the overlapping pixels to inspect the cut wafer includes:

[0041] Using a segmented photo of a target die and a partial wafer photo of the target die as images to be stitched;

[0042] Acquire the position of the shooting point in the image to be stitched as the shooting position;

[0043] 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;

[0044] Obtaining a coordinate range of each of the images to be stitched according to the size of the local wafer photo, the point coordinates, and the shooting position;

[0045] According to the coordinates of the corner points, obtain the coordinate range of the complete image of the target die;

[0046] Obtaining the seg position according to the coordinate range of the image to be stitched and the coordinate range of the target die complete image;

[0047] According to the seg positions, the images to be stitched are stitched into a complete target die image;

[0048] The seg position is used to indicate the position of the partial die area in the image to be stitched relative to the complete image of the target die.

[0049] In a second aspect, a post-cut wafer inspection device is provided, the device comprising:

[0050] A shooting unit, used for shooting with a large field of view to obtain a complete wafer photo;

[0051] a separation point acquisition unit, which acquires separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0052] A trajectory acquisition unit, configured to acquire a shooting trajectory according to the separation points;

[0053] The shooting unit is further configured to capture multiple local wafer photos using a small field of view according to the shooting trajectory;

[0054] an identification unit, configured to identify corner points based on the partial wafer photograph;

[0055] a stitching unit, configured to obtain the die to which each of the partial wafer photos belongs based on the shooting trajectory and the corner points;

[0056] The splicing unit is further configured to segment the partial wafer photo according to the die to which each partial wafer photo belongs, so as to obtain segmented photos;

[0057] 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;

[0058] The stitching unit is further configured to stitch the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die, so as to inspect the cut wafer.

[0059] The size of each of the partial wafer photos is smaller than the size of a complete die.

[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 method, device, computer equipment and storage medium for detecting wafers after cutting. The method includes: 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 local wafer photos; based on the local wafer photos, identifying corner points; based on the shooting trajectory and the corner points, obtaining the die to which each local wafer photo belongs; based on the die to which each local wafer photo belongs, segmenting the local wafer photos to obtain segmented photos; based on the shooting trajectory and the size of the local wafer photos, obtaining overlapping pixels of adjacent local wafer photos; based on the shooting trajectory and the overlapping pixels, splicing the segmented photos belonging to the target die and the local wafer photos belonging to the target die into a complete image of the target die to detect the wafer after cutting; wherein the size of each local wafer photo is smaller than the size of a complete die. In the method of an embodiment of the present invention, before stitching partial wafer photos into a complete image of the target die, corner points are first identified, the partial wafer photos are segmented according to the corner points, and the parts that do not belong to the target die are cut off before stitching. This saves a lot of image recognition processes in the stitching process, improves the stitching speed, saves system resources, and reduces 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 3Shown 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 The embodiment of the present invention is shown Figure 5 Schematic diagram of the corner points in 1-1, 1-4, 3-1 and 3-4;

[0073] Figure 9 Shown is a schematic diagram of a separated image according to an embodiment of the present invention;

[0074] Figure 10 Schematic diagram of a complete image of a target die after stitching according to an embodiment of the present invention;

[0075] Figure 11 Schematic diagram of a wafer inspection device after dicing according to an embodiment of the present invention;

[0076] Figure 12 FIG. 1 is a diagram showing the internal structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0077] 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.

[0078] Figure 1 FIG. 1 is an application environment diagram of the wafer inspection method after dicing according to an embodiment of the present invention. Figure 1The 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.

[0079] The post-cut wafer detection method of the present invention is applied to the terminal 110 and / or the server 120 .

[0080] Figure 2 FIG. 1 is a flow chart of a method for detecting wafers after dicing according to an embodiment of the present invention. Figure 2 As shown, the method includes:

[0081] Step 210 , photographing with a wide field of view to obtain a complete wafer photograph;

[0082] Step 220 , obtaining separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0083] Step 230: obtaining a shooting trajectory according to the separation point;

[0084] Step 240 , taking a plurality of local wafer photos using a small field of view according to the shooting trajectory;

[0085] Step 250 , identifying corner points based on the partial wafer photograph;

[0086] Step 260 , obtaining the die to which each of the partial wafer photos belongs based on the shooting trajectory and the corner points;

[0087] Step 270 , segmenting the partial wafer photos according to the die to which each partial wafer photo belongs to obtain segmented photos;

[0088] Step 280 , obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos;

[0089] Step 290 , stitching the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die based on the shooting trajectory and the overlapping pixels, so as to inspect the cut wafer;

[0090] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0091] The products after cutting a single wafer can be multiple independent chips / integrated circuits / wafers / die, and the chips / integrated circuits / wafers / die cut from the wafer can also be called die.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] Figure 3 FIG. 1 is a schematic diagram of a complete wafer photograph according to 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.

[0096] 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.

[0097] 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.

[0098] Wide-field imaging allows for a wider field of view, allowing for full wafer image capture. However, this results in lower precision and clarity, making identification and subsequent inspection difficult. 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. Therefore, multiple partial wafer images must be stitched together to create a complete image of the target die.

[0099] In the method of the embodiment of the present invention, corner points are identified based on the partial wafer photos; the die to which each partial wafer photo belongs is obtained based on the shooting trajectory and the corner points; the partial wafer photos are segmented according to the die to which each partial wafer photo belongs to obtain segmented photos; and during stitching, the segmented photos and the partial wafer photos belonging to the target die are stitched together by overlapping pixels. The method of the embodiment of the present invention can save a lot of image recognition processes by stitching segmented photos with overlapping pixels, thereby improving the stitching speed; in addition, by reducing the image recognition process, it can also reduce the stored images. Therefore, the embodiment of the present invention can also save system resources and reduce costs.

[0100] In the embodiment of the present invention, step 230, obtaining the shooting trajectory according to the separation point, includes:

[0101] Obtaining the distance between every two adjacent separation points as a first distance;

[0102] Obtaining the maximum value of all the first distances as the second distance;

[0103] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0104] 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.

[0105] 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.

[0106] The size of a local wafer photo is usually rectangular or square, you can refer to Figure 5 shown.

[0107] In an embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points.

[0108] The acquiring of the shooting trajectory according to the second distance and the size of the local wafer photograph includes:

[0109] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0110] Obtaining shooting points according to the number of shots;

[0111] Planning a scanning path according to the shooting points;

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] In the embodiment of the present invention, the distance between two adjacent shooting points is preferably equidistant.

[0121] In an embodiment of the present invention, in step 250, identifying corner points based on the partial wafer photograph includes:

[0122] Acquire a photo including a separation point from the partial wafer photo as a first image;

[0123] Corner points are identified from the first image according to the recognition template.

[0124] In an embodiment of the present invention, step 260 of obtaining the die to which each of the partial wafer photos belongs based on the shooting trajectory and the corner points includes:

[0125] According to the recognition template, obtaining the position type of each corner point;

[0126] Acquire the first image belonging to the same die according to the position type and the shooting trajectory;

[0127] taking the partial wafer photograph excluding the separation point as a second image;

[0128] According to the shooting trajectory, obtaining the die to which each second image belongs;

[0129] The position types include a first type, a second type, a third type and a fourth type, and the same die includes four corner points, and the position types of the four corner points are different.

[0130] Figure 5 Shown is a schematic diagram of multiple local wafer photos of an embodiment of the present invention. For the convenience 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, 3-4.

[0131] Figure 5 , 1-1, 1-4, 3-1 and 3-4 are first images containing separation points, and the remaining images are second images.

[0132] The die pattern on each wafer can be obtained before dicing. Typically, in high-volume production, the dies on a wafer are identical; in low-volume production, the dies on a wafer may be different.

[0133] Before inspecting the cut wafer, an identification template needs to be made according to the die pattern on the wafer.

[0134] In an embodiment of the present invention, the recognition template may include a pattern pattern near each corner point of the die, or a mark pattern pattern near each corner point, and may also include an internal pattern pattern of the die, etc., which will not be repeated here.

[0135] By identifying the template, it is possible to identify which part of the die the corner points contained in the local wafer image belong to, thereby determining the location type of the corner points.

[0136] Figure 8 Shown Figure 5 Schematic diagram of the corner points 1-1, 1-4, 3-1 and 3-4 in Figure 8As shown in Figure 1-1, there are four corner points, denoted as corner points E, F, G, and H. By comparing them with the recognition template, we can identify corner point E as the lower right corner, corner point F as the lower left corner, corner point G as the upper right corner, and corner point H as the upper left corner. We can also consider corner point E to be of the first type, corner point F to be of the second type, corner point G to be of the third type, and corner point H to be of the fourth type.

[0137] Similarly, Figure 8 1-4 in the figure also include four corner points, which are respectively denoted as corner point I, corner point J, corner point K and corner point L, where I is the lower right corner point, J is the lower left corner point, K is the upper right corner point, and L is the upper left corner point.

[0138] Figure 8 3-1 includes corner point M, corner point N, corner point O and corner point P, and 3-4 includes corner point Q, corner point R, corner point S and corner point T.

[0139] The same die includes four corner points, and the position types of the four corner points are different. For example, the four corner points are of the first type, the second type, the third type and the fourth type respectively. It can also be considered that the four corner points include the lower right corner point, the lower left corner point, the upper right corner point and the upper left corner point.

[0140] by Figure 8 For example, a die includes corner point H, corner point K, corner point N and corner point O. For the convenience of expression, the die including corner point H, corner point K, corner point N and corner point O is denoted as Z, or as the target die.

[0141] Based on the shooting trajectory, we can know that parts of 1-2, 1-3, and 1-1, 1-2 from 1-1 including corner point H to 1-4 including corner point K belong to Z. Similarly, part of 2-1 from 1-1 including corner point H to 3-1 including corner point N also belongs to Z. Based on the shooting trajectory, we can know that 2-2, 2-3, 2-4, 3-2, and 2-3 also belong to Z.

[0142] In this embodiment of the present invention, "belonging to the same die" means that some or all images in a partial wafer photograph belong to the same die. For example, the lower half of 3-2, the lower half of 3-3, the right half of 2-1, all of 2-2, all of 2-3, the upper half of 3-2, and the upper half of 3-3 also belong to Z. However, the upper half of 3-2 does not belong to Z. However, these partial wafer photographs are still considered to belong to Z.

[0143] In an embodiment of the present invention, step 270 of segmenting the partial wafer photo according to the die to which each partial wafer photo belongs to obtain segmented photos includes:

[0144] The partial wafer photos are segmented according to the die to which each partial wafer photo belongs, so that images in the segmented photos belong to a single die.

[0145] refer to Figure 5 and Figure 8 As shown, taking Z as the target die, the lower right portion of 1-1, the lower half of 1-2, the lower half of 1-3, the right half of 2-1, the entirety of 2-2, the entirety of 2-3, the left half of 2-4, the upper right portion of 3-1, the upper half of 3-2, the upper half of 3-3, and the upper left portion of 3-4 belong to Z. For example, the partial wafer photo can be segmented. For example, 1-1 can be divided into the upper left, lower left, upper right, and lower right portions. This means that 1-1 is divided into four segmented images. The lower right portion containing corner point H belongs to Z, while the remaining three portions belong to three different dies. Similarly, 2-1 can be divided into two segmented images. The segmentation methods for other partial wafer photos are not described here.

[0146] When segmenting a local wafer photo, it can be done based on the connection lines between corner points, edge features, edge white / black flow, etc.

[0147] refer to Figure 9 As shown, connecting the corner point in 1-1 to the corner point in 1-4 can have two lines, one of which is the line between the corner points of Z, such as the red line in the figure, and the other is the line between the corner points of other dies, such as the blue line in the figure. For subsequent detection, a certain amount of redundancy needs to be left, so segmentation can be performed along the blue line above; or segmentation can be performed in the middle of the two lines.

[0148] In the embodiment of the present invention, step 280 of obtaining overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes:

[0149] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0150] Obtaining the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0151] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0152] In an embodiment of the present invention, in step 290, based on the shooting trajectory and the overlapping pixels, the segmented photos belonging to the target die and the partial wafer photos belonging to the target die are spliced into a complete image of the target die to inspect the cut wafer, including:

[0153] Using a segmented photo of a target die and a partial wafer photo of the target die as images to be stitched;

[0154] Acquire the position of the shooting point in the image to be stitched as the shooting position;

[0155] 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;

[0156] Obtaining a coordinate range of each of the images to be stitched according to the size of the local wafer photo, the point coordinates, and the shooting position;

[0157] According to the coordinates of the corner points, obtain the coordinate range of the complete image of the target die;

[0158] Obtaining the seg position according to the coordinate range of the image to be stitched and the coordinate range of the target die complete image;

[0159] According to the seg positions, the images to be stitched are stitched into a complete target die image;

[0160] The seg position is used to indicate the position of the partial die area in the image to be stitched relative to the complete image of the target die.

[0161] In the embodiment of the present invention, seg may also be referred to as a partitioned area.

[0162] 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.

[0163] If the shooting point is located at the center of the local wafer photo, it can be calculated by the following formula:

[0164] X-axis overlap pixels = X-axis size of the local wafer photo - X-axis point distance between adjacent shooting points.

[0165] Y-axis overlap pixels = Y-axis size of the local wafer photo - Y-axis point distance between adjacent shooting points.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] In one embodiment of the present invention, it is assumed that the center of the camera field of view of the first shooting point of the camera is the origin, and the X-coordinate axis and the Y-coordinate axis are both in pixels. The camera field of view, that is, the size of each local wafer photo is 30*30, the distance between adjacent camera shooting points on the X axis is 20, and the distance between two adjacent camera shooting points on the Y axis is also 20. The center of the camera field of view of 1-1 is used as the origin of the coordinate axis, that is, the shooting point is the center of the local wafer photo 1-1, and coincides with the corner point H, the coordinates of the corner point H are (0, 0), then the 1-1 coordinate range is counted as four points: (-15, 15), (15, 15), (15, -15), (-15, -15).

[0170] 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).

[0171] The center coordinates of 2-1 are (0, -20), and the coordinate ranges are (-15, -5), (15, -5), (15, -35), and (-15, -35).

[0172] Assuming that the coordinates of the four corner points of a complete die are H (0, 0), K (K1, 0), N (0, N1), and Q (K1, N1), the seg position of each partial wafer photo can be obtained based on the coordinate range of each partial wafer photo.

[0173] 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.

[0174] Figure 10 FIG. 1 is a schematic diagram of a complete image of a target die after stitching according to an embodiment of the present invention.

[0175] 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.

[0176] In an embodiment of the present invention, after stitching the segmented photos belonging to the target die and the partial wafer photos belonging to the target die into a complete image of the target die according to the shooting trajectory and the overlapping pixels, the method may further include:

[0177] Get the position of each target die complete image in the complete wafer photo.

[0178] Obtaining the position of each target die complete image in the complete wafer photograph includes:

[0179] Obtain the conversion parameters from the small field of view coordinate system to the large field of view coordinate system;

[0180] In the embodiment of the present invention, the conversion parameters from the small field of view coordinate system to the large field of view coordinate system are obtained according to the lens magnification, the sampling scaling factor and the pixel accuracy;

[0181] The lens magnification is the lens magnification from the large field of view to the small field of view.

[0182] 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 target die complete image in the complete wafer photo.

[0183] 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.

[0184] In the embodiment of the present invention, a wide field of view is used to obtain a clear die image in order to obtain a high-definition complete image of the target die for subsequent inspection. In the embodiment of the present invention, when stitching partial wafer photos into a complete image of the target die, corner points are first identified. Combined with the shooting trajectory, partial wafer photos belonging to the same die can be more accurately determined. Furthermore, the embodiment of the present invention performs segmentation before stitching and stitches by overlapping pixels, avoiding large-area image recognition, which consumes a long time and requires computing and storage resources. Therefore, the embodiment of the present invention can save system resources and speed up the image stitching process.

[0185] like Figure 11 As shown, the present invention also provides a post-cut wafer inspection device, the device comprising:

[0186] The photographing unit 1110 is configured to photograph a whole wafer using a wide field of view;

[0187] A separation point acquisition unit 1120 acquires separation points between a plurality of dies cut from the wafer based on the complete wafer photograph;

[0188] The trajectory acquisition unit 1130 is configured to acquire a shooting trajectory according to the separation points;

[0189] The photographing unit 1110 is further configured to acquire multiple local wafer photos using a small field of view according to the photographing trajectory;

[0190] an identification unit 1140, configured to identify corner points based on the partial wafer photograph;

[0191] A stitching unit 1150 is configured to obtain the die to which each of the partial wafer photos belongs based on the shooting trajectory and the corner points;

[0192] The splicing unit 1150 is further configured to segment the partial wafer photo according to the die to which each partial wafer photo belongs, to obtain segmented photos;

[0193] The stitching unit 1150 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;

[0194] The stitching unit 1150 is further configured to stitch the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die, so as to inspect the cut wafer.

[0195] The size of each of the partial wafer photos is smaller than the size of a complete die.

[0196] In the embodiment of the present invention, the trajectory acquisition unit 1130 is further configured to:

[0197] Obtaining the distance between every two adjacent separation points as a first distance;

[0198] Obtaining the maximum value of all the first distances as the second distance;

[0199] A shooting trajectory is obtained according to the second distance and the size of the local wafer photo.

[0200] In the embodiment of the present invention, the shooting trajectory includes a scanning path and shooting points.

[0201] The trajectory acquisition unit 1130 is further configured to:

[0202] Obtaining the number of photographs between every two adjacent separation points according to the second distance and the size of the local wafer photograph;

[0203] Obtaining shooting points according to the number of shots;

[0204] Planning a scanning path according to the shooting points;

[0205] 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.

[0206] In the embodiment of the present invention, the identification unit 1140 is further configured to:

[0207] Acquire a photo including a separation point from the partial wafer photo as a first image;

[0208] Corner points are identified from the first image according to the recognition template.

[0209] In the embodiment of the present invention, the splicing unit 1150 is further configured to:

[0210] According to the recognition template, obtaining the position type of each corner point;

[0211] Acquire the first image belonging to the same die according to the position type and the shooting trajectory;

[0212] taking the partial wafer photograph excluding the separation point as a second image;

[0213] According to the shooting trajectory, obtaining the die to which each second image belongs;

[0214] The position types include a first type, a second type, a third type, and a fourth type. The same die includes four corner points, and the position types of the four corner points are different.

[0215] In the embodiment of the present invention, the splicing unit 1150 is further configured to:

[0216] Obtaining the distance between adjacent shooting points in the shooting trajectory;

[0217] Obtaining the overlapping pixels according to the point distance and the size of the local wafer photograph;

[0218] The overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels.

[0219] In the embodiment of the present invention, the splicing unit 1150 is further configured to:

[0220] Using a segmented photo of a target die and a partial wafer photo of the target die as images to be stitched;

[0221] Acquire the position of the shooting point in the image to be stitched as the shooting position;

[0222] 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;

[0223] Obtaining a coordinate range of each of the images to be stitched according to the size of the local wafer photo, the point coordinates, and the shooting position;

[0224] According to the coordinates of the corner points, obtain the coordinate range of the complete image of the target die;

[0225] Obtaining the seg position according to the coordinate range of the image to be stitched and the coordinate range of the target die complete image;

[0226] According to the seg positions, the images to be stitched are stitched into a complete target die image;

[0227] The seg position is used to indicate the position of the partial die area in the image to be stitched relative to the complete image of the target die.

[0228] The embodiments of the present invention can save a lot of image recognition processes, improve the splicing speed, save system resources and reduce costs.

[0229] An embodiment of the present invention also provides a computer device, including 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 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 partial wafer photos, identifying corner points; based on the shooting trajectory and the corner points, obtaining the die to which each partial wafer photo belongs; based on the die to which each partial wafer photo belongs, segmenting the partial wafer photos to obtain segmented photos; 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 segmented photos belonging to the target die and the partial wafer photos belonging to the target die into a complete image of 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.

[0230] 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 partial wafer photos, identifying corner points; based on the shooting trajectory and the corner points, obtaining the die to which each of the partial wafer photos belongs; based on the die to which each of the partial wafer photos belongs, segmenting the partial wafer photos to obtain segmented photos; 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 segmented photos belonging to the target die and the partial wafer photos belonging to the target die into a complete image of the target die to detect the cut wafer; wherein the size of each of the partial wafer photos is smaller than the size of a complete die.

[0231] 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.

[0232] 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.

[0233] Figure 12 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 12As 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.

[0234] Those skilled in the art will understand that Figure 12 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.

[0235] 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).

[0236] 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.

[0237] 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 photo; 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; identifying corner points according to the partial wafer photograph; Obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory and the corner points; Segmenting the partial wafer photos according to the die to which each partial wafer photo belongs to obtain segmented photos; acquiring overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos; splicing the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die according to the shooting trajectory and the overlapping pixels, 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 acquiring overlapping pixels of adjacent partial wafer photos according to the shooting trajectory and the size of the partial wafer photos includes: Obtain the distance between adjacent shooting points in the shooting trajectory, According to the point distance and the size of the local wafer photo, the overlapping pixels are obtained, Wherein, the overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels; The step of stitching the segmented photos of the target die and the partial wafer photos of the target die into a complete image of the target die according to the shooting trajectory and the overlapping pixels, so as to inspect the cut wafer, includes: The segmented photo of the target die and the partial wafer photo of the target die are used as images to be stitched. Acquire the position of the shooting point in the image to be stitched as the shooting position; According to the shooting trajectory and the shooting position, the coordinates of each shooting point in the small field of view coordinate system are obtained. According to the size of the local wafer photo, the point coordinates and the shooting position, the coordinate range of each image to be stitched is obtained, According to the corner point coordinates, the coordinate range of the complete image of the target die is obtained. According to the coordinate range of the image to be stitched and the coordinate range of the target die complete image, the seg position is obtained. According to the seg position, the images to be stitched are stitched into the complete image of the target die, The seg position is used to indicate the position of the partial die area in the image to be stitched relative to the complete image of the target die.

2. The method according to claim 1, characterized in that The acquiring of the shooting trajectory according to the separation point includes: Obtaining the distance between every two adjacent separation points as a first distance; Obtaining 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.

3. The method according to claim 2, 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.

4. The method according to claim 2, characterized in that The step of identifying corner points based on the partial wafer photograph includes: Acquire a photo including a separation point from the partial wafer photo as a first image; Corner points are identified from the first image according to the recognition template.

5. The method according to claim 4, characterized in that The step of obtaining the die to which each of the partial wafer photos belongs according to the shooting trajectory and the corner points includes: According to the recognition template, obtaining the position type of each corner point; Acquire the first image belonging to the same die according to the position type and the shooting trajectory; taking the partial wafer photograph excluding the separation point as a second image; According to the shooting trajectory, obtaining the die to which each second image belongs; The position types include a first type, a second type, a third type, and a fourth type. The same die includes four corner points, and the position types of the four corner points are different.

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; an identification unit, configured to identify corner points based on the partial wafer photograph; a stitching unit, configured to obtain the die to which each of the partial wafer photos belongs based on the shooting trajectory and the corner points; The splicing unit is further configured to segment the partial wafer photo according to the die to which each partial wafer photo belongs, so as to obtain segmented photos; 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 segmented photos of the target die and the partial wafer photos of the target die into a complete image of 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 splicing unit is also used for: Obtain the distance between adjacent shooting points in the shooting trajectory, According to the point distance and the size of the local wafer photo, the overlapping pixels are obtained, Wherein, the overlapping pixels include X-axis overlapping pixels and Y-axis overlapping pixels; The splicing unit is also used for: The segmented photo of the target die and the partial wafer photo of the target die are used as the images to be stitched. Obtaining the position of the shooting point in the image to be stitched as the shooting position, According to the shooting trajectory and the shooting position, the coordinates of each shooting point in the small field of view coordinate system are obtained. According to the size of the local wafer photo, the point coordinates and the shooting position, the coordinate range of each image to be stitched is obtained, According to the corner point coordinates, obtain the coordinate range of the target die complete image, According to the coordinate range of the image to be stitched and the coordinate range of the target die complete image, the seg position is obtained. According to the seg position, the images to be stitched are stitched into a complete target die image. The seg position is used to indicate the position of the partial die area in the image to be stitched relative to the complete image of the target die.

7. 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.

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

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