Cut correction and early warning method in wafer cutting process, wafer cutting equipment

Abstract

The present invention provides a method for correcting and warning a cut in a wafer cutting process, and a wafer cutting device, and belongs to the technical field of wafer laser cutting. In the method, before cutting, the deviation between a target theoretical cutting line and its corresponding target standard cutting line is calculated based on a Mark template image, and when the deviation is not greater than the position tolerance of the cut, or when the deviation is not greater than the measurement tolerance of a camera, and when the signs of the deviations of the previous preset number of times are the same, the target theoretical cutting line is corrected, and then cutting is performed according to the corrected cutting line, thereby improving the cutting accuracy. In addition, after cutting, the measured position deviation of the cut and the measured width of the cut are also detected, so that abnormalities in equipment or process parameters can be discovered in time, wafer scrapping can be avoided, and the yield rate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer laser cutting, and in particular to a cut correction and early warning method in a wafer cutting process, and a wafer cutting device. Background Art

[0002] Wafer dicing is a key step in the semiconductor manufacturing process. Its main function is to cooperate with the splitter to divide a complete wafer into independent semiconductor chips (i.e., grains) for subsequent packaging and application. In order to reduce the average raw material and manufacturing costs of a single chip, reducing the gap between grains and increasing the chip yield per unit area of ​​the wafer is a current development trend. Due to the reduction in the gap between grains, higher requirements are placed on the width, edge quality, and position accuracy of the cut during wafer dicing. The general tolerance needs to be controlled within 5μm, or even within 1 to 2um.

[0003] At present, based on the laser scribing process and the visual alignment technology before cutting, the position accuracy of the cut is guaranteed to a certain extent. That is, through the visual alignment before cutting, the position of a cutting line is found through the Mark point, and then it is offset multiple times according to the size of the grain, so as to accurately find the position of each cut. However, due to the linearity error of the scribing equipment carrier, the accumulation of artificial grain size measurement errors, possible process parameter mismatch, grain distribution deviation in some wafer front-end processes, and micro-displacement during the processing caused by wafer deformation or loose fixation, the actual cut may have deviations in morphology and position, resulting in a decrease in cutting quality and failure to meet the precision requirements of wafer scribing.

[0004] In summary, how to improve the accuracy and yield of the wafer dicing process has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a cut correction and early warning method and wafer cutting equipment in the wafer cutting process to alleviate the technical problems of low precision and low yield of the existing wafer cutting process.

[0006] In a first aspect, an embodiment of the present invention provides a method for correction and early warning of a cut in a wafer cutting process, comprising:

[0007] Determine the theoretical cutting line of the wafer to be cut based on the pre-collected Mark template image, and calculate the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line, wherein the target theoretical cutting line is the current theoretical cutting line in the preset theoretical cutting lines in the theoretical cutting line;

[0008] If the deviation is greater than the preset position tolerance of the cut, a cut position deviation alarm is issued and the cutting operation is suspended;

[0009] If the deviation is not greater than the position tolerance of the cut, and the deviation is greater than the measurement tolerance of a camera in a wafer cutting device, the target theoretical cutting line is corrected according to the deviation to obtain a corrected cutting line;

[0010] If the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, then the mean of the deviations of the previous preset times is calculated to obtain the mean deviation, and the target theoretical cutting line is corrected according to the mean deviation to obtain the corrected cutting line;

[0011] If the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are different, the target theoretical cutting line is used as the corrected cutting line;

[0012] The wafer cutting device is enabled to cut the wafer to be cut according to the corrected cutting line;

[0013] After dicing, obtaining an incision image captured when the camera center of the camera in the wafer cutting device is aligned with the midpoint of the corrected cutting line, and determining the incision upper edge line, the incision lower edge line and the incision center line according to the incision image;

[0014] Projecting the image center of the incision image onto the incision center line to obtain a projection point, and calculating the measured position deviation of the incision according to the projection point and the image center, and calculating the measured width of the incision according to the incision upper edge line and the incision lower edge line;

[0015] If the measured position deviation of the incision is greater than the position tolerance of the incision, or the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, an incision quality alarm is issued.

[0016] Furthermore, the method further comprises:

[0017] If the difference between the actual measured width of all the cuts of the wafer to be cut and the theoretical width of the cut is not greater than the width tolerance, and the signs of the differences between the actual measured width of all the cuts of the wafer to be cut and the theoretical width of the cut are the same, an alarm is issued after the wafer to be cut is cut;

[0018] If the signs of the actually measured position deviations of all the cuts of the wafer to be cut are the same, an alarm is issued after the wafer to be cut is cut.

[0019] Furthermore, determining a theoretical cutting line of the wafer to be cut based on the pre-collected Mark template image includes:

[0020] After the wafer cutting equipment is calibrated, the wafer to be cut is fixed on the XY stage, and then the wafer to be cut is visually aligned and aligned based on the Mark template image, so that the channel direction of the wafer to be cut is parallel to the XY axis of the XY stage, and the target Mark coordinates closest to the center of the wafer to be cut are obtained, and the third distance between the target Mark coordinates and the corresponding target channel center is determined;

[0021] Wherein, the wafer cutting equipment includes: a cutting head, a first camera on the same side of the cutting head and parallel to the cutting head, a second camera on the opposite side of the cutting head and parallel to the cutting head, and an XY stage perpendicular to the cutting head. The positions of the cutting head, the first camera and the second camera are relatively fixed. The XY stage is used to carry the wafer to be cut and drive the wafer to be cut to move in the XY direction relative to the cutting head, and the XY stage can rotate around the Z axis. The calibration includes: a first affine matrix from the pixel coordinates of the first camera to the stage coordinates of the XY stage, a second affine matrix from the pixel coordinates of the second camera to the stage coordinates, a first distance of the first camera relative to the cutting head, and a second distance of the second camera relative to the cutting head. The target Mark coordinates are Mark coordinates obtained based on the Mark template image;

[0022] The theoretical cutting line is determined according to the target Mark coordinates, the third distance, the grain size of the wafer to be cut, and the interval between the grains.

[0023] Furthermore, the wafer cutting equipment calibration process includes:

[0024] Using a camera affine calibration method to calibrate a first affine matrix from the pixel coordinates of the first camera to the stage coordinates of the XY stage, and using the camera affine calibration method to calibrate a second affine matrix from the pixel coordinates of the second camera to the stage coordinates;

[0025] Fixing a transparent calibration sheet on the XY stage, turning on the cutting head and moving the XY stage so that the cutting head cuts a marking line on the transparent calibration sheet, and recording a first XY stage coordinate when the cutting head is aligned with the midpoint of the marking line;

[0026] Move the XY stage so that the camera center of the first camera is aligned with the midpoint of the marking line, record the current second XY stage coordinates, and calculate a first distance of the first camera relative to the cutting head according to the first XY stage coordinates and the second XY stage coordinates;

[0027] The XY stage is moved so that the camera center of the second camera is aligned with the midpoint of the marking line, and the current third XY stage coordinates are recorded, and the second distance of the second camera relative to the cutting head is calculated based on the first XY stage coordinates and the third XY stage coordinates.

[0028] Further, calculating the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line includes:

[0029] The XY stage is moved so that the camera center of the camera is aligned with the theoretical Mark point corresponding to the target theoretical cutting line, and a theoretical image is acquired, wherein if the Mark template image is on the upper surface of the wafer, the camera is the first camera, and if the Mark template image is on the lower surface of the wafer, the camera is the second camera, and the theoretical Mark point is calculated according to the target channel center, the grain size, the interval between the grains and the third distance;

[0030] Determine the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image, and calculate the deviation of the target theoretical cutting line and its corresponding target standard cutting line according to the coordinates of the theoretical Mark point and the position coordinates of the Mark point in the theoretical image.

[0031] Further, determining the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image includes:

[0032] Obtaining a Mark image based on matching the Mark template image at the position of the theoretical Mark point;

[0033] The theoretical image and the Mark image are matched by using a feature extraction method to obtain the position coordinates of the Mark point in the Mark image in the theoretical image.

[0034] Further, obtaining a cut image captured when the camera center of a camera in the wafer cutting device is aligned with the midpoint of the corrected cutting line, and determining the cut upper edge line, the cut lower edge line and the cut center line according to the cut image, including:

[0035] Moving the XY stage so that the camera center of the camera is aligned with the midpoint of the corrected cutting line, and acquiring the incision image;

[0036] The upper edge line of the incision is obtained by fitting the upper edge of the incision in the incision image, and the lower edge line of the incision is obtained by fitting the lower edge of the incision in the incision image;

[0037] The incision center line is calculated based on the incision upper edge line and the incision lower edge line.

[0038] Furthermore, the method further comprises:

[0039] For other theoretical cutting lines except the preset theoretical cutting line, correction is performed according to the offset of the last target theoretical cutting line to obtain the corrected cutting line, wherein the offset includes: the deviation or the mean deviation.

[0040] Furthermore, the method further comprises:

[0041] If the wafer cutting device that has been calibrated vibrates, the wafer cutting device is recalibrated.

[0042] In a second aspect, an embodiment of the present invention further provides a wafer cutting device, wherein the wafer cutting device is used to execute the cut correction and early warning method in the wafer cutting process described in any one of the first aspects.

[0043] In an embodiment of the present invention, a method for incision correction and early warning in a wafer cutting process is provided, comprising: determining a theoretical cutting line of a wafer to be cut based on a pre-collected Mark template image, and calculating a deviation between a target theoretical cutting line in the theoretical cutting line and a corresponding target standard cutting line, wherein the target theoretical cutting line is a current theoretical cutting line in a preset theoretical cutting line in the theoretical cutting line; if the deviation is greater than a preset incision position tolerance, an incision position deviation alarm is issued, and the cutting operation is suspended; if the deviation is not greater than the incision position tolerance, and the deviation is greater than the measurement tolerance of a camera in a wafer cutting device, the target theoretical cutting line is corrected according to the deviation to obtain a corrected cutting line; if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, the mean of the deviations of the previous preset times is calculated to obtain the mean deviation, and the target theoretical cutting line is corrected according to the mean deviation. Perform calibration to obtain a calibrated cutting line; if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are different, the target theoretical cutting line is used as the calibrated cutting line; the wafer cutting equipment is enabled to cut the wafer to be cut according to the calibrated cutting line; after cutting, the incision image captured when the camera center of the camera in the wafer cutting equipment is aligned with the midpoint of the calibrated cutting line is obtained, and the upper edge line, the lower edge line and the center line of the incision are determined according to the incision image; the image center of the incision image is projected onto the incision center line to obtain the projection point, and the measured position deviation of the incision is calculated according to the projection point and the image center, and the measured width of the incision is calculated according to the upper edge line and the lower edge line of the incision; if the measured position deviation of the incision is greater than the position tolerance of the incision, or the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, an incision quality alarm is issued. From the above description, it can be seen that in the incision correction and early warning method in the wafer cutting process of the present invention, before cutting, the deviation between the target theoretical cutting line and its corresponding target standard cutting line is calculated based on the Mark template image, and when the deviation is not greater than the position tolerance of the incision, or the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, the target theoretical cutting line is corrected, and then the cutting is performed according to the corrected cutting line, thereby improving the cutting accuracy. In addition, after cutting, the measured position deviation and the measured width of the incision are also detected. In this way, abnormalities in equipment or process parameters can be discovered in time, wafer scrapping can be avoided, and yield can be improved, thereby alleviating the technical problems of low precision and low yield of the existing wafer cutting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0045] Figure 1 A flow chart of a method for correction and early warning of a cut in a wafer cutting process provided by an embodiment of the present invention;

[0046] Figure 2 A schematic structural diagram of a wafer cutting device provided by an embodiment of the present invention;

[0047] Figure 3 A schematic diagram of a theoretical cutting line provided by an embodiment of the present invention;

[0048] Figure 4 A schematic diagram of a corrected cutting line provided by an embodiment of the present invention;

[0049] Figure 5 A schematic diagram of collecting an incision image after cutting in the case where both the incision and the mark provided in the embodiment of the present invention are on the upper surface;

[0050] Figure 6 A schematic diagram of collecting an incision image after cutting in a case where the incision provided in an embodiment of the present invention is on the upper surface and the Mark is on the lower surface;

[0051] Figure 7 A schematic diagram of calibration provided by an embodiment of the present invention;

[0052] Figure 8 A schematic diagram of a theoretical image collected according to an embodiment of the present invention;

[0053] Fig. 9 A schematic diagram of collecting Marks before cutting provided by an embodiment of the present invention;

[0054] Fig.10 A flowchart of another method for cutting correction and early warning in a wafer cutting process provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The traditional wafer dicing process has low precision and low yield.

[0057] Based on this, in the incision correction and early warning method in the wafer cutting process of the present invention, before cutting, the deviation between the target theoretical cutting line and its corresponding target standard cutting line is calculated based on the Mark template image, and when the deviation is not greater than the position tolerance of the incision, or the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, the target theoretical cutting line is corrected, and then cutting is performed according to the corrected cutting line, thereby improving the cutting accuracy. In addition, after cutting, the measured position deviation and the measured width of the incision are also detected. In this way, abnormalities in equipment or process parameters can be discovered in time, wafer scrapping can be avoided, and the yield rate can be improved.

[0058] To facilitate understanding of this embodiment, a cut correction and early warning method in a wafer cutting process disclosed in an embodiment of the present invention is first introduced in detail.

[0059] Embodiment 1:

[0060] According to an embodiment of the present invention, an embodiment of a cut correction and early warning method in a wafer cutting process is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0061] Figure 1 is a flow chart of a method for cutting correction and early warning in a wafer cutting process according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0062] Step S102, determining the theoretical cutting line of the wafer to be cut based on the pre-collected Mark template image, and calculating the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line, wherein the target theoretical cutting line is the current theoretical cutting line in the preset theoretical cutting lines in the theoretical cutting line;

[0063] In an embodiment of the present invention, the above-mentioned cut correction and warning method in the wafer cutting process can be applied to a wafer cutting device with a visual alignment function, such as Figure 2 As shown, the wafer cutting equipment includes: a cutting head, a first camera on the same side of the cutting head and parallel to the cutting head, a second camera on the opposite side of the cutting head and parallel to the cutting head, and an XY stage perpendicular to the cutting head. The positions of the cutting head, the first camera and the second camera are relatively fixed. The XY stage is used to carry the wafer to be cut and drive the wafer to be cut to move in the XY direction relative to the cutting head, and the XY stage can rotate around the Z axis. Figure 2The XY stage shown has the positive direction of the X axis pointing horizontally to the right, the positive direction of the Y axis pointing inward on the paper, and the positive direction of the Z axis pointing vertically upward. In addition, the cutting head, the first camera, and the second camera are mounted on the Z axis and can move up and down to achieve focus on the wafer to be cut.

[0064] The theoretical cutting line of the wafer to be cut is determined as Figure 3 As shown, after the theoretical cutting line is determined, the target theoretical cutting line is determined in the theoretical cutting line, and the target theoretical cutting line is the current theoretical cutting line in the preset theoretical cutting lines in the theoretical cutting lines. When implemented, in order to improve the efficiency of correction, it is not necessary to calibrate each theoretical cutting line, but to calibrate once at intervals of a preset number of theoretical cutting lines, such as calibrating once every 2 theoretical cutting lines. In this way, the preset theoretical cutting line can be determined (that is, the theoretical cutting line obtained every 2 theoretical cutting lines, and the target theoretical cutting line is the current theoretical cutting line in the above preset theoretical cutting lines (that is, the theoretical cutting line to be corrected currently)).

[0065] The target standard cutting line is specifically a standard cutting line without actual deviation.

[0066] Step S104, if the deviation is greater than the preset position tolerance of the cut, a cut position deviation alarm is issued and the cutting operation is suspended;

[0067] Specifically, the wafer dicing process generally has corresponding quality control indicators, including: the position tolerance of the cut tol pos , the theoretical width of the incision w 、Width tolerance tol w The measurement tolerance of the first camera and the second camera (ie, the measurement tolerance of the camera) is tol meas Must be smaller than the position tolerance of the cutout tol pos , to ensure that the visual alignment accuracy before cutting is higher than the accuracy requirement of the dicing process.

[0068] If the deviation is greater than the preset position tolerance of the cutout, that is, |Δy1|>tol pos , indicating that the deviation of the generated target theoretical cutting line relative to the actual cutting position exceeds the deviation allowed by the dicing process, that is, the deviation is very outrageous and the dicing cannot be continued through correction. At this time, there must be an abnormality, which requires an alarm, suspending the dicing, and then manual intervention to avoid scrapping the wafer to be cut after the dicing process.

[0069] Step S106, if the deviation is not greater than the position tolerance of the cut, and the deviation is greater than the measurement tolerance of the camera in the wafer cutting equipment, the target theoretical cutting line is corrected according to the deviation to obtain a corrected cutting line;

[0070] Specifically, if the deviation is not greater than the position tolerance of the cutout, and the deviation is greater than the measurement tolerance of the camera, that is, tol meas <|Δy1|≤tol pos , then the target theoretical cutting line is corrected according to the deviation, that is, the target theoretical cutting line is corrected according to the offset of Δy1 to obtain the corrected cutting line, such as Figure 4 As shown (with Figure 3 The corrected cutting line corresponding to the theoretical cutting line).

[0071] Step S108, if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, then the mean of the deviations of the previous preset times is calculated to obtain the mean deviation, and the target theoretical cutting line is corrected according to the mean deviation to obtain a corrected cutting line;

[0072] Specifically, the deviation is no greater than the measurement tolerance of the camera, that is, |Δy1|≤tol mean , and the signs of the deviations of the previous preset times are the same, that is, the deviations Δy1 of the previous k times (including this time) are all positive or negative (that is, the deviations have a unidirectional drift), indicating that the position of the generated target theoretical cutting line is likely to have a deviation. At this time, the average of the deviations of the previous preset times is calculated, that is, the average of k times Δy1 is taken as the correction amount Δy k , and according to the mean deviation Δy k Correct the target theoretical cutting line to obtain the corrected cutting line, such as Figure 4 As shown (with Figure 3 The corrected cutting line corresponding to the theoretical cutting line).

[0073] Step S110, if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are different, the target theoretical cutting line is used as the corrected cutting line;

[0074] Specifically, the deviation is no greater than the measurement tolerance of the camera, that is, |Δy1|≤tol meas , and the signs of the deviations of the previous preset times are different, that is, the deviations Δy1 of the previous k times (including this time) are not positive or negative at the same time, then Δy1 is a random error caused by measurement, and there is no need to correct the position of the target theoretical cutting line.

[0075] Step S112, causing the wafer cutting equipment to cut the wafer to be cut according to the calibrated cutting line;

[0076] Step S114, after dicing, obtaining a cut image captured when the camera center of a camera in the wafer cutting device is aligned with the midpoint of the corrected cut line, and determining the cut upper edge line, the cut lower edge line and the cut center line according to the cut image;

[0077] Specifically, after cutting along the corrected cutting line, it is necessary to check the cut quality after cutting, and to give an alarm when the cut quality exceeds the tolerance. When implementing, align the camera center of the camera (if the cut is on the upper surface of the wafer, then the camera is the first camera, if the cut is on the lower surface of the wafer, then the camera is the second camera) with the midpoint of the corrected cutting line, and collect the cut image, such as Figure 5 and Figure 6 As shown, the solid line frame is the incision image, and then, the upper edge line, the lower edge line and the center line of the incision are determined according to the incision image.

[0078] Step S116, projecting the image center of the incision image onto the incision center line to obtain a projection point, and calculating the measured position deviation of the incision according to the projection point and the image center, and calculating the measured width of the incision according to the incision upper edge line and the incision lower edge line;

[0079] Specifically, the image center of the incision image is the midpoint of the corrected cutting line. The image center of the incision image is projected onto the incision center line to obtain a projection point.

[0080] The measured position deviation of the incision is the distance Δy2 (including direction) from the projection point to the center of the image, and the measured width of the incision is meas w It is the distance between the upper edge of the incision and the lower edge of the incision.

[0081] Step S118: If the measured position deviation of the incision is greater than the position tolerance of the incision, or the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, an incision quality alarm is issued.

[0082] Specifically, if the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, that is, |meas w -theo w |>tol w , or the measured position deviation of the cutout is greater than the position tolerance of the cutout, that is, |Δy2|>tol pos , there is an abnormality, an alarm is required, the subsequent dicing process is suspended, and then manual intervention is performed to avoid scrapping of wafer processing.

[0083] At this point, the cutting of the target theoretical cutting line is completed, and then the next target theoretical cutting line is operated according to the above process until all the target theoretical cutting lines are processed.

[0084] In an embodiment of the present invention, a method for incision correction and early warning in a wafer cutting process is provided, comprising: determining a theoretical cutting line of a wafer to be cut based on a pre-collected Mark template image, and calculating a deviation between a target theoretical cutting line in the theoretical cutting line and a corresponding target standard cutting line, wherein the target theoretical cutting line is a current theoretical cutting line in a preset theoretical cutting line in the theoretical cutting line; if the deviation is greater than a preset incision position tolerance, an incision position deviation alarm is issued, and the cutting operation is suspended; if the deviation is not greater than the incision position tolerance, and the deviation is greater than the measurement tolerance of a camera in a wafer cutting device, the target theoretical cutting line is corrected according to the deviation to obtain a corrected cutting line; if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, the mean of the deviations of the previous preset times is calculated to obtain the mean deviation, and the target theoretical cutting line is corrected according to the mean deviation. Perform calibration to obtain a calibrated cutting line; if the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are different, the target theoretical cutting line is used as the calibrated cutting line; the wafer cutting equipment is enabled to cut the wafer to be cut according to the calibrated cutting line; after cutting, the incision image captured when the camera center of the camera in the wafer cutting equipment is aligned with the midpoint of the calibrated cutting line is obtained, and the upper edge line, the lower edge line and the center line of the incision are determined according to the incision image; the image center of the incision image is projected onto the incision center line to obtain the projection point, and the measured position deviation of the incision is calculated according to the projection point and the image center, and the measured width of the incision is calculated according to the upper edge line and the lower edge line of the incision; if the measured position deviation of the incision is greater than the position tolerance of the incision, or the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, an incision quality alarm is issued. From the above description, it can be seen that in the incision correction and early warning method in the wafer cutting process of the present invention, before cutting, the deviation between the target theoretical cutting line and its corresponding target standard cutting line is calculated based on the Mark template image, and when the deviation is not greater than the position tolerance of the incision, or the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, the target theoretical cutting line is corrected, and then the cutting is performed according to the corrected cutting line, thereby improving the cutting accuracy. In addition, after cutting, the measured position deviation and the measured width of the incision are also detected. In this way, abnormalities in equipment or process parameters can be discovered in time, wafer scrapping can be avoided, and yield can be improved, thereby alleviating the technical problems of low precision and low yield of the existing wafer cutting process.

[0085] The above content briefly introduces the cut correction and early warning method in the wafer cutting process of the present invention, and the specific contents involved are described in detail below.

[0086] In an optional embodiment of the present invention, the method further comprises the following steps:

[0087] (1) If the difference between the actual measured width of all the cuts on the wafer to be cut and the theoretical width of the cut is not greater than the width tolerance, and the signs of the differences between the actual measured width of all the cuts on the wafer to be cut and the theoretical width of the cut are the same, an alarm is issued after the wafer to be cut is cut;

[0088] Specifically, after all the target theoretical cutting lines of the wafer to be cut are processed, if the difference between the measured width of all the incisions of the wafer to be cut and the theoretical width of the incision is not greater than the width tolerance, that is, all the |meas w -theo w |≤tol w , and the difference between the measured width of all the incisions of the wafer to be cut and the theoretical width of the incision has the same sign, that is, all the meas w -theo w If the value is always positive or negative (i.e. the width error drifts in one direction), an alarm is required after the cutting is completed, and manual intervention is required to check the process parameters, so as to further improve the accuracy of the next wafer cutting.

[0089] (2) If the signs of the measured position deviations of all the cuts on the wafer to be cut are the same, an alarm is issued after the wafer to be cut is cut.

[0090] Specifically, if the signs of the measured position deviations of all the cuts on the wafer to be cut are the same, that is, all Δy2 of the wafer to be cut is always positive or always negative (that is, the position error drifts in one direction), an alarm is also required after the cutting is completed, and manual intervention is required to check whether the distance calibration from the camera to the cutting head is appropriate.

[0091] In an optional embodiment of the present invention, determining a theoretical cutting line of a wafer to be cut based on a pre-collected Mark template image specifically includes the following steps:

[0092] (1) After the wafer cutting equipment is calibrated, the wafer to be cut is fixed on the XY stage, and then the wafer to be cut is visually aligned and aligned based on the Mark template image, so that the channel direction of the wafer to be cut is parallel to the XY axis of the XY stage, and the target Mark coordinates closest to the center of the wafer to be cut are obtained, and the third distance between the target Mark coordinates and the corresponding target channel center is determined; wherein the calibration includes: a first affine matrix from the pixel coordinates of the first camera to the stage coordinates of the XY stage, a second affine matrix from the pixel coordinates of the second camera to the stage coordinates, a first distance from the first camera to the cutting head and a second distance from the second camera to the cutting head, and the target Mark coordinates are the Mark coordinates obtained based on the Mark template image;

[0093] Before performing incision correction and warning, if the wafer cutting equipment has been installed but not calibrated, then the wafer cutting equipment needs to be calibrated, and subsequent operations can be performed after the calibration is completed; if the wafer cutting equipment has been calibrated before, and the calibrated wafer cutting equipment has not vibrated since the calibration was completed to this moment (for example, there is no collision with the calibrated wafer cutting equipment, and the relative positions of the cutting head, the first camera and the second camera have not changed), then, there is no need to calibrate the wafer cutting equipment at this time; if the calibrated wafer cutting equipment vibrates, the wafer cutting equipment should be recalibrated.

[0094] Specifically, after visual correction and alignment, the channel direction of the wafer to be cut is parallel to the XY axis of the XY stage. There is only one pre-collected Mark template image, but the Mark template image can be matched to obtain the same Mark image around each grain. The center point of the Mark image is the Mark point, and the position of the Mark point (the position on the XY stage) is the Mark coordinate. During implementation, the center of the wafer to be cut can be determined first, and then the candidate Mark image can be obtained by matching the Mark template image around the center of the circle, and the candidate Mark points of each candidate Mark image and their corresponding candidate Mark coordinates can be obtained. Finally, according to the position coordinates of the center of the circle and each candidate Mark coordinate, the target Mark coordinate P0 (x P0 ,y P0 ). The target channel center may be the channel center closest to the target Mark coordinates, and the positions of the channel centers have been determined in advance. The third distance may be expressed as Δ3 (including the distance in the X direction and the distance in the Y direction).

[0095] (2) Determine the theoretical cutting line based on the target Mark coordinates, the third distance, the grain size of the wafer to be cut, and the interval between the grains.

[0096] Specifically, Figure 3 As shown, the target Mark coordinate P0 (x P0 ,y P0 ) is shifted downward by the Y direction distance of the third distance Δ3, the middle theoretical cutting line can be obtained, and then the theoretical cutting line can be determined according to the grain size of the wafer to be cut and the interval between the grains. Figure 3 The step value h in (specifically, the grain height + the interval between grains in the grain size of the wafer to be cut) is set, and then the middle theoretical cutting line is shifted up and down multiple times according to the step value h, so that each theoretical cutting line can be determined (it can be determined that each theoretical cutting line is relative to the target Mark coordinate P0 (x P0 ,y P0) step value).

[0097] In an optional embodiment of the present invention, the process of calibrating the wafer cutting equipment includes the following steps:

[0098] (1) using a camera affine calibration method to calibrate a first affine matrix from pixel coordinates of a first camera to stage coordinates of an XY stage, and using a camera affine calibration method to calibrate a second affine matrix from pixel coordinates of a second camera to stage coordinates;

[0099] Specifically, a camera affine calibration method such as a nine-point calibration method is used to calibrate the affine transformation relationship from the pixel coordinates of the first camera and the second camera to the stage coordinates, respectively, to obtain two affine matrices.

[0100] Because the position measured in the camera is in pixels, but to calculate the offset, it needs to be converted to the unit of the XY stage (usually millimeters). This process requires the use of an affine matrix.

[0101] (2) Fixing the transparent calibration sheet on the XY stage, turning on the cutting head and moving the XY stage so that the cutting head cuts the marking line on the transparent calibration sheet, and recording the first XY stage coordinate when the cutting head is aligned with the midpoint of the marking line;

[0102] Specifically, Figure 7 Referring to the marking lines shown in FIG. 1 , the first XY stage coordinate is marked as (x0, y0).

[0103] (3) moving the XY stage so that the camera center of the first camera is aligned with the midpoint of the marking line, recording the current coordinates of the second XY stage, and calculating a first distance of the first camera relative to the cutting head according to the first XY stage coordinates and the second XY stage coordinates;

[0104] Specifically, Figure 7 As shown, the solid line frame is the field of view of the camera, the coordinates of the second XY stage are marked as (x1, y1), and the first distance Δ1 of the first camera relative to the cutting head is = (x1-x0, y1-y0).

[0105] (4) Move the XY stage so that the camera center of the second camera is aligned with the midpoint of the marking line, and record the current third XY stage coordinates, and calculate the second distance of the second camera relative to the cutting head based on the first XY stage coordinates and the third XY stage coordinates.

[0106] Specifically, the coordinates of the third XY stage are marked as (x2, y2), and the second distance Δ2 between the second camera and the cutting head is = (x2-x0, y2-y0), and the distance calibration between the two cameras and the cutting head is completed.

[0107] In an optional embodiment of the present invention, calculating the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line specifically includes the following steps:

[0108] (1) The XY stage is moved so that the camera center is aligned with the theoretical Mark point corresponding to the target theoretical cutting line, and a theoretical image is acquired, wherein if the Mark template image is on the upper surface of the wafer, the camera is the first camera, and if the Mark template image is on the lower surface of the wafer, the camera is the second camera, and the theoretical Mark point is calculated based on the target channel center, the grain size, the interval between the grains, and the third distance;

[0109] Specifically, for the first target theoretical cutting line, based on the target theoretical cutting line relative to the target Mark coordinate P0 (x P0 ,y P0 ), Δ(first distance or second distance, if the Mark template image is on the upper surface, the camera is the first camera, the corresponding distance is the first distance, that is, Δ=Δ1; if the Mark template image is on the lower surface, the camera is the second camera, the corresponding distance is the second distance, that is, Δ=Δ2), target Mark coordinate P0 (x P0 ,y P0 ) Move the XY stage to move the camera center to the theoretical Mark point corresponding to the theoretical cutting line of the alignment target, and collect the theoretical image, such as Figure 8 The above theoretical Mark point is calculated based on the target channel center, grain size, interval between grains and the third distance. When implemented, first calculate the target channel center + preset number (the number of target theoretical cutting line offsets relative to the target channel center) h step value = the theoretical channel center corresponding to the target theoretical cutting line, and then offset the theoretical channel center corresponding to the target theoretical cutting line by the third distance Δ3 to calculate the theoretical Mark point; it can also be the target theoretical cutting line relative to the target Mark coordinate P0 (x P0 ,y P0 ) step value + target Mark coordinate P0(x P0 ,y P0 ) can calculate the theoretical Mark point.

[0110] Figure 8 In the figure, the solid-line frame is the Mark image obtained by matching the Mark template image near the target theoretical cutting line (i.e., the Mark image obtained based on the Mark template image, and the center point of the Mark image is the Mark point obtained based on the Mark template image below), and the dotted-line frame is the theoretical image.

[0111] It should be noted that before executing this process, if it is found that there is a risk of rotation error on the XY stage of the wafer to be cut, you can Fig. 9 As shown, the deviations of the two marks on the left and right edges are measured for alarm judgment respectively; the average of the deviations of the two marks is taken for position correction.

[0112] (2) Determine the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image, and calculate the deviation between the target theoretical cutting line and its corresponding target standard cutting line according to the coordinates of the theoretical Mark point and the position coordinates of the Mark point in the theoretical image.

[0113] Specifically, the above deviation is equal to the distance (Δx1, Δy1) from the coordinates of the theoretical Mark point to the position coordinates of the Mark point in the theoretical image.

[0114] Determining the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image specifically includes the following steps:

[0115] (21) Obtaining a Mark image based on the position matching of the Mark template image at the theoretical Mark point;

[0116] (22) The feature extraction method is used to match the theoretical image and the Mark image to obtain the position coordinates of the Mark point in the Mark image in the theoretical image.

[0117] Specifically, by matching the Mark image and the theoretical image, the position coordinates of the Mark point of the Mark image in the theoretical image are obtained. In implementation, the acquired theoretical image and the Mark image are matched based on feature extraction methods such as contour feature fitting or template matching to obtain the position coordinates of the Mark point in the Mark image in the theoretical image.

[0118] In an optional embodiment of the present invention, an incision image acquired when the camera center of a camera in a wafer cutting device is aligned with the midpoint of a corrected cutting line is obtained, and an incision upper edge line, an incision lower edge line and an incision center line are determined according to the incision image, specifically comprising the following steps:

[0119] (1) moving the XY stage so that the camera center is aligned with the midpoint of the calibrated cutting line, and acquiring the incision image;

[0120] When implemented, based on the step value, Δ, Δ3 and P0 of the target theoretical cutting line corresponding to the corrected cutting line relative to P0, the XY stage is moved so that the camera center of the camera moves to the midpoint of the aligned corrected cutting line, and the incision image is collected, such as Figure 5 and Figure 6 As shown, the solid line frame is the incision image.

[0121] (2) fitting the upper edge of the incision in the incision image to obtain an upper edge line of the incision, and fitting the lower edge of the incision in the incision image to obtain a lower edge line of the incision;

[0122] (3) The incision center line is calculated based on the incision upper edge line and the incision lower edge line.

[0123] In an optional embodiment of the present invention, the method further comprises the following steps:

[0124] For other theoretical cutting lines except the preset theoretical cutting line, correction is performed according to the offset of the last target theoretical cutting line to obtain a corrected cutting line, wherein the offset includes: deviation or mean deviation.

[0125] Specifically, for some theoretical cutting lines that do not need to be corrected according to the above process (such as the theoretical cutting lines in the aforementioned content that are corrected every 2 theoretical cutting lines), they can be simplified corrected according to the offset of the target theoretical cutting line of the last correction, and then cut. After cutting, there is no need to perform incision quality inspection.

[0126] in addition, Figure 3 and Figure 4 What is shown in the figure is the scribing of the wafer to be cut in one direction. After the scribing is completed, the wafer to be cut is rotated 90 degrees, and the process of visually straightening and aligning the wafer to be cut based on the pre-collected Mark template image is returned until the scribing of the wafer to be cut in the other direction is completed. At this point, the scribing of the entire wafer to be cut is completed.

[0127] In order to facilitate a better understanding of the incision correction and early warning method in the wafer cutting process of the present invention, the specific process is described again below. Fig.10 As shown:

[0128] Step 1, using a camera affine calibration method such as a nine-point calibration method, respectively calibrate the affine transformation relationship from the pixel coordinates of the first camera and the second camera to the XY stage coordinates to obtain two affine matrices;

[0129] Step 2, calibrating the distance between the first camera and the second camera and the cutting head; before the wafer cutting equipment vibrates, replace different wafers, and step 2 and step 1 do not need to be performed again;

[0130] Step 2.1, fix the transparent calibration film on the XY stage, turn on the cutting head and move the XY stage so that the cutting head draws a mark line on the calibration film, and record the first XY stage coordinate (x0, y0) when the cutting head is aligned with the midpoint of the mark line, such as Figure 7 As shown;

[0131] Step 2.2, move the XY stage until the center of the first camera is aligned with the midpoint of the marking line, and record the coordinates of the second XY stage at this time (x1, y1). The first distance between the first camera and the cutting head is Δ1 = (x1-x0, y1-y0);

[0132] Step 2.3, move the XY stage until the center of the second camera is aligned with the midpoint of the marking line, and record the coordinates of the third XY stage at this time (x2, y2). The second distance of the second camera relative to the cutting head is Δ2 = (x2-x0, y2-y0). The distance calibration of the two cameras relative to the cutting head is now completed.

[0133] Step 3: After the wafer is fixed on the XY stage, the wafer is visually aligned and aligned based on the pre-collected Mark template image, so that the channel direction of the wafer is parallel to the XY axis of the XY stage, and a target Mark coordinate P0 (x P0 ,y P0 ) (i.e., obtaining the target Mark coordinates closest to the center of the wafer), assuming that the third distance between the created target Mark coordinates and the corresponding target channel center is Δ3 (including the distance in the X direction and the distance in the Y direction);

[0134] Step 4: Based on the height of the grain and the target Mark coordinate P0 (x P0 ,y P0 ), the third distance Δ3 and the interval between the grains can generate a theoretical cutting line (such as Figure 3 As shown), each theoretical cutting line has a step value relative to P0;

[0135] Step 5, take the first theoretical cutting line;

[0136] Step 6: Before cutting the theoretical cutting line, the cutting line position is corrected or an alarm is issued based on the Mark. In this step, if the Mark is on the upper surface of the wafer, the camera is the first camera, and Δ=Δ1; if the Mark is on the lower surface of the wafer, the camera is the second camera, and Δ=Δ2.

[0137] Step 6.1: For the theoretical cutting line, move the XY stage based on the step value relative to P0, Δ and P0, so that the center of the camera moves to the theoretical Mark point corresponding to the theoretical cutting line of the target, such as Figure 8 As shown, theoretical images are collected;

[0138] Step 6.2, based on feature extraction methods such as contour feature fitting or template matching, match the captured theoretical image and Mark image to obtain the position coordinates of the Mark point in the theoretical image. The deviation of the theoretical cutting line relative to the actual standard cutting line without deviation is the distance (Δx1, Δy1) from the coordinates of the theoretical Mark point to the position coordinates of the Mark point in the theoretical image.

[0139] Step 6.3, alarm suspension: if |Δy1|>tol pos , indicating that the deviation of the generated theoretical cutting line position relative to the actual cutting position exceeds the deviation allowed by the dicing process. At this time, there must be an abnormality, and an alarm is required for manual intervention to avoid wafer processing scrapping;

[0140] Step 6.4, theoretical cutting line position correction: If tol meas <|Δy1|≤tol pos , indicating that the generated theoretical cutting line position has a deviation. At this time, the position of the theoretical cutting line needs to be corrected according to the offset of Δy1; if |Δy1|>tol meas , but the deviations Δy1 of the previous k (k ≥ 5) times (including this time) are all positive or negative (that is, the deviation has a unidirectional drift), which indicates that the position of the generated theoretical cutting line is likely to have a deviation. In this case, the average of k times Δy1 is taken as the correction value Δy k , according to the mean deviation Δy k Correct the position of the theoretical cutting line; if |Δy1|≤tol meas , and the previous k deviations Δy1 are not positive or negative at the same time, then Δy1 is a random error caused by measurement, and there is no need to correct the position of the theoretical cutting line;

[0141] Step 7, use the cutting head to scribe the corrected cutting line on the wafer; if the equipment stability is good, in order to improve efficiency, the same correction amount Δy1 can be used to continuously correct multiple subsequent theoretical cutting lines and cut, and the subsequent cutting lines may not perform step 8;

[0142] Step 8, after the calibrated cutting line is cut, the cut quality is checked and an out-of-tolerance alarm is executed;

[0143] Step 8.1, based on the step value relative to P0, Δ, Δ3 and P0, the camera center is moved to the midpoint of the aligned and corrected cutting line, and the incision image (such as Figure 5 and Figure 6 shown);

[0144] Step 8.2, grab the upper and lower edges of the incision in the incision image and fit straight lines to obtain the upper edge line and the lower edge line of the incision respectively, and solve the center lines of the two to obtain the incision center line;

[0145] Step 8.3, project the image center of the incision image along the Y direction onto the incision centerline to obtain the projection point. The measured position deviation of the incision is the distance Δy2 (including direction) from the projection point to the image center. The distance between the upper edge line of the straight incision and the lower edge line of the incision is the measured width of the incision meas w ;

[0146] Step 8.4, alarm pause: if |meas w -theo w |>tol w , or, |Δy2|>tol pos , then there is an abnormality, and an alarm is required for manual intervention to avoid scrapping of wafer processing;

[0147] Step 9, take the next theoretical cutting line, and repeat steps 6 to 8 until all theoretical cutting lines are processed;

[0148] Step 10, rotate 90 degrees, and execute steps 3 to 9 again to cut the vertical cutting line;

[0149] Step 11, alarm after processing: If all cutting lines have |meas during incision detection w -theo w |≤tol w And meas w -theo w If Δy2 is always positive or always negative (i.e., the width error drifts in one direction), an alarm is required after the cutting is completed, and manual intervention is required to check the process parameters; if Δy2 is always positive or always negative (i.e., the position error drifts in one direction) for all cutting lines during incision detection, an alarm is also required after the cutting is completed, and manual intervention is required to check whether the distance calibration from the camera to the cutting head is appropriate.

[0150] For step 6, if there is a risk of rotation error on the XY stage, Fig. 9 As shown, the deviations of the two marks on the left and right edges are measured for alarm judgment respectively; the average of the deviations of the two marks is taken for position correction.

[0151] The incision correction and early warning method in the wafer cutting process of the present invention has the following advantages:

[0152] 1. The accuracy of wafer dicing can be improved by correcting the theoretical cutting line before wafer dicing.

[0153] 2. Through the alarm based on the mark and the cut before and after the theoretical cutting line, abnormal equipment or process parameters can be discovered in time to avoid wafer scrapping and improve the yield;

[0154] 3. The unidirectional drift error after the whole wafer is cut can be used as an indication of equipment calibration or the rationality of process parameters, and timely inspection and correction can be made to further improve the processing accuracy of the equipment.

[0155] Embodiment 2:

[0156] The embodiment of the present invention further provides a wafer cutting device, which is used to execute the cut correction and early warning method in the wafer cutting process in the first embodiment.

[0157] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0158] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0159] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for correction and early warning of cuts during wafer cutting, characterized in that: include: Determine the theoretical cutting line of the wafer to be cut based on the pre-collected Mark template image, and calculate the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line, wherein the target theoretical cutting line is the current theoretical cutting line in the preset theoretical cutting lines in the theoretical cutting line; If the deviation is greater than the preset position tolerance of the cut, a cut position deviation alarm is issued and the cutting operation is suspended; If the deviation is not greater than the position tolerance of the cut, and the deviation is greater than the measurement tolerance of a camera in a wafer cutting device, the target theoretical cutting line is corrected according to the deviation to obtain a corrected cutting line; If the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are the same, then the mean of the deviations of the previous preset times is calculated to obtain the mean deviation, and the target theoretical cutting line is corrected according to the mean deviation to obtain the corrected cutting line; If the deviation is not greater than the measurement tolerance of the camera, and the signs of the deviations of the previous preset times are different, the target theoretical cutting line is used as the corrected cutting line; The wafer cutting device is enabled to cut the wafer to be cut according to the corrected cutting line; After dicing, obtaining an incision image captured when the camera center of the camera in the wafer cutting device is aligned with the midpoint of the corrected cutting line, and determining the incision upper edge line, the incision lower edge line and the incision center line according to the incision image; Projecting the image center of the incision image onto the incision center line to obtain a projection point, and calculating the measured position deviation of the incision according to the projection point and the image center, and calculating the measured width of the incision according to the incision upper edge line and the incision lower edge line; If the measured position deviation of the incision is greater than the position tolerance of the incision, or the difference between the measured width of the incision and the preset theoretical width of the incision is greater than the preset width tolerance, an incision quality alarm is issued.

2. The method according to claim 1, characterized in that The method further comprises: If the difference between the actual measured width of all the cuts of the wafer to be cut and the theoretical width of the cut is not greater than the width tolerance, and the signs of the differences between the actual measured width of all the cuts of the wafer to be cut and the theoretical width of the cut are the same, an alarm is issued after the wafer to be cut is cut; If the signs of the actually measured position deviations of all the cuts of the wafer to be cut are the same, an alarm is issued after the wafer to be cut is cut.

3. The method according to claim 1, characterized in that Determine the theoretical cutting line of the wafer to be cut based on the pre-collected Mark template image, including: After the wafer cutting equipment is calibrated, the wafer to be cut is fixed on the XY stage, and then the wafer to be cut is visually aligned and aligned based on the Mark template image, so that the channel direction of the wafer to be cut is parallel to the XY axis of the XY stage, and the target Mark coordinates closest to the center of the wafer to be cut are obtained, and the third distance between the target Mark coordinates and the corresponding target channel center is determined; Wherein, the wafer cutting equipment includes: a cutting head, a first camera on the same side of the cutting head and parallel to the cutting head, a second camera on the opposite side of the cutting head and parallel to the cutting head, and an XY stage perpendicular to the cutting head. The positions of the cutting head, the first camera and the second camera are relatively fixed. The XY stage is used to carry the wafer to be cut and drive the wafer to be cut to move in the XY direction relative to the cutting head, and the XY stage can rotate around the Z axis. The calibration includes: a first affine matrix from the pixel coordinates of the first camera to the stage coordinates of the XY stage, a second affine matrix from the pixel coordinates of the second camera to the stage coordinates, a first distance of the first camera relative to the cutting head, and a second distance of the second camera relative to the cutting head. The target Mark coordinates are Mark coordinates obtained based on the Mark template image; The theoretical cutting line is determined according to the target Mark coordinates, the third distance, the grain size of the wafer to be cut, and the interval between the grains.

4. The method according to claim 3, characterized in that The wafer cutting equipment calibration process includes: Using a camera affine calibration method to calibrate a first affine matrix from the pixel coordinates of the first camera to the stage coordinates of the XY stage, and using the camera affine calibration method to calibrate a second affine matrix from the pixel coordinates of the second camera to the stage coordinates; Fixing a transparent calibration sheet on the XY stage, turning on the cutting head and moving the XY stage so that the cutting head cuts a marking line on the transparent calibration sheet, and recording a first XY stage coordinate when the cutting head is aligned with the midpoint of the marking line; Move the XY stage so that the camera center of the first camera is aligned with the midpoint of the marking line, record the current second XY stage coordinates, and calculate a first distance of the first camera relative to the cutting head according to the first XY stage coordinates and the second XY stage coordinates; The XY stage is moved so that the camera center of the second camera is aligned with the midpoint of the marking line, and the current third XY stage coordinates are recorded, and the second distance of the second camera relative to the cutting head is calculated based on the first XY stage coordinates and the third XY stage coordinates.

5. The method according to claim 3, characterized in that: Calculating the deviation between the target theoretical cutting line in the theoretical cutting line and the corresponding target standard cutting line includes: The XY stage is moved so that the camera center of the camera is aligned with the theoretical Mark point corresponding to the target theoretical cutting line, and a theoretical image is acquired, wherein if the Mark template image is on the upper surface of the wafer, the camera is the first camera, and if the Mark template image is on the lower surface of the wafer, the camera is the second camera, and the theoretical Mark point is calculated according to the target channel center, the grain size, the interval between the grains and the third distance; Determine the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image, and calculate the deviation of the target theoretical cutting line and its corresponding target standard cutting line according to the coordinates of the theoretical Mark point and the position coordinates of the Mark point in the theoretical image.

6. The method according to claim 5, characterized in that Determining the position coordinates of the Mark point obtained based on the Mark template image in the theoretical image includes: Obtaining a Mark image based on matching the Mark template image at the position of the theoretical Mark point; The theoretical image and the Mark image are matched by using a feature extraction method to obtain the position coordinates of the Mark point in the Mark image in the theoretical image.

7. The method according to claim 3, characterized in that Acquiring an incision image acquired when the camera center of a camera in the wafer cutting device is aligned with the midpoint of the corrected cutting line, and determining an incision upper edge line, an incision lower edge line, and an incision center line according to the incision image, including: Moving the XY stage to align the camera center of the camera with the midpoint of the corrected cutting line, and acquiring the incision image; The upper edge line of the incision is obtained by fitting the upper edge of the incision in the incision image, and the lower edge line of the incision is obtained by fitting the lower edge of the incision in the incision image; The incision center line is calculated based on the incision upper edge line and the incision lower edge line.

8. The method according to claim 1, characterized in that The method further comprises: For other theoretical cutting lines except the preset theoretical cutting line, correction is performed according to the offset of the last target theoretical cutting line to obtain the corrected cutting line, wherein the offset includes: the deviation or the mean deviation.

9. The method according to claim 3, characterized in that: The method further comprises: If the wafer cutting device that has been calibrated vibrates, the wafer cutting device is recalibrated.

10. A wafer cutting device, characterized in that: The wafer cutting equipment is used to execute the cut correction and early warning method in the wafer cutting process according to any one of claims 1 to 9.

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