Method for calculating cutting channel position through wafer visual automatic alignment

Abstract

The invention discloses a method for calculating the position of a cutting channel through wafer visual automatic alignment. A low-precision camera and a high-precision camera are adopted to make a low-precision visual matching template and a high-precision visual matching template for the alpha face and the beta face respectively, and then the difference value from the corresponding visual matching template to the cutting channel intersection position is calibrated; determining the center position O of the wafer; taking a position A at the edge of the wafer in the alpha surface of the wafer, calculating a position B and a position C, calculating angle deviation values of the cutting channels AB and BC, and rotating the wafer to enable the cutting channels AB and BC to be matched with the alpha surface high-precision visual matching template; calculating horizontal positions Xi, starting positions Yi and ending positions Yi of all cutting channels on the alpha surface of the wafer; and calculating the horizontal position Xj, the starting position Yj and the ending position Yj of all cutting channels on the beta surface of the wafer by adopting the same method. The low-precision camera is matched with the high-precision camera, so that the accuracy of the position of the cutting channel is ensured.

Description

Technical field:

[0001] The invention belongs to the technical field of semiconductor wafer production, and in particular relates to a method for calculating cutting path positions by automatic wafer vision alignment. Background technology:

[0002] In the semiconductor chip manufacturing process, wafer laser cutting is one of the most important processes in the packaging and testing stage. In order to ensure the qualified rate of chips, the wafer cutting accuracy is very high. In order to improve the wafer cutting accuracy, a visual method is generally used to determine the location of the wafer cutting path.

[0003] In the existing visual methods, the camera's shooting accuracy is low, and the difference between the cutting path and the visual matching template is large. Therefore, it is a problem that needs to be solved to design a method to reduce the difference between the cutting path and the visual matching template and improve the cutting path position accuracy.

[0004] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention:

[0005] The object of the present invention is to provide a method for calculating the position of a cutting line by automatic wafer vision alignment, thereby overcoming the defects in the above-mentioned prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for calculating the position of a cutting path by automatic wafer vision alignment, the steps of which are as follows: (1) placing a wafer on a wafer fixing turntable, manually leveling the wafer, dividing the wafer cutting surface into an α surface and a β surface, wherein the β surface is obtained by rotating the α surface by 90°, using a low-precision camera and a high-precision camera to make a low-precision visual matching template for the α surface of the wafer and a high-precision visual matching template for the α surface of the wafer respectively, and then calibrating the difference between the low-precision visual matching template for the α surface and the high-precision visual matching template for the α surface to the intersection position of the α surface cutting path, and similarly making a low-precision visual matching template for the β surface and a high-precision visual matching template for the β surface, and then calibrating the difference between the low-precision visual matching template for the β surface and the high-precision visual matching template for the β surface to the intersection position of the β surface cutting path;

[0007] (2) Calculate the positions of the four edge points of the wafer based on the wafer radius r0 and the center of the wafer fixed turntable, use a low-precision camera to find the precise positions of the four edge points from bright to dark, verify whether the circular error composed of the precise positions of the four edge points is within the set range, and determine the wafer center position O based on the precise positions of the four edge points;

[0008] (3) According to the wafer center position O calculated in step (2), position A located at the edge of the wafer is taken within the wafer α surface, and a low-precision camera is used to move spirally on the wafer α surface, and the cutting path intersection position at position A is found by matching with the low-precision visual matching template of the α surface, and the cutting path intersection position at position A is moved downward by N grain size distances from the cutting path intersection position at position A to calculate position B, and then the low-precision visual matching template of the α surface is used to match to find the cutting path intersection position at position B, and the line connecting position A and position B is used as the cutting path AB, and according to the wafer center position O, the angle deviation value between the cutting path AB and the vertical line passing through the wafer center position O is calculated, and according to the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle so that the cutting path AB is parallel to the vertical line, and the high-precision camera matches the cutting path AB with the high-precision visual matching template of the α surface to straighten it;

[0009] (4) Based on position A, the high-precision camera finds position C on the wafer α surface that is symmetrical to the center of position A. The high-precision camera moves spirally on the wafer α surface. Through the α surface high-precision visual matching template matching, the cutting path intersection position at position A and the cutting path intersection position at position C are found respectively. The line connecting position A and position C is taken as the cutting path AC. Based on the wafer center position O, the angle deviation value between the cutting path AC and the vertical line passing through the wafer center position O is calculated. Based on the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle so that the cutting path AC is parallel to the vertical line. The high-precision camera repeatedly matches the cutting path AC with the α surface high-precision visual matching template until the difference between the cutting path AC and the α surface high-precision visual matching template is within the set range. The midpoint of the cutting path AC is taken as the center of the cutting path on the wafer α surface, and the midpoint of the cutting path AC coincides with position B. Based on position B, the horizontal dimension of the grain, the wafer radius and the wafer center position O, the horizontal position X of all the cutting paths on the wafer α surface is calculated. i , start position Y i and end position Y i` ;

[0010] (5) Rotate position B 90 degrees to obtain the center position B' of the wafer β-surface cutting path. Calculate position A' and position C' upward and downward respectively based on position B'. Use the β-surface low-precision visual matching template to match the cutting path intersection position at position A' and the cutting path intersection position at position C'. Take the line connecting position A' and position C' as the cutting path A'C'. Calculate the angle deviation between the cutting path A'C' and the vertical line passing through the wafer center position O according to the wafer center position O. According to the angle deviation value, the wafer is fixed on the turntable. Drive the wafer to rotate the corresponding angle to make the cutting path A`C` parallel to the vertical line; the high-precision camera repeatedly matches the cutting path A`C` with the high-precision visual matching template of the β surface until the difference between the cutting path A`C` and the high-precision visual matching template of the β surface is within the set range; take the midpoint of the cutting path A`C` as the center of the cutting path on the β surface of the wafer, and the midpoint of the cutting path A`C` coincides with the position B`; according to the position B`, the horizontal size of the grain, the wafer radius and the wafer center position O, calculate the horizontal position X of all the cutting paths on the β surface of the wafer j , start position Y j and end position Y j` .

[0011] Preferably, in the technical solution, in step (1), a low-precision camera or a high-precision camera selects feature points on the α surface of the wafer according to the wafer pattern to make a corresponding visual matching template; when the low-precision camera or the high-precision camera completes the corresponding visual matching template, the feature point is at the center of the image, and the position coordinates of the feature point are recorded, and then the low-precision camera or the high-precision camera is moved so that the center position of the image coincides with the center position of the intersection of the α surface cutting path, and the current position coordinates are subtracted from the position coordinates of the feature point to obtain the difference between the low-precision visual matching template of the α surface or the high-precision visual matching template of the α surface and the intersection position of the α surface cutting path; in the same way, the difference between the low-precision visual matching template of the β surface or the high-precision visual matching template of the β surface and the intersection position of the β surface cutting path is obtained.

[0012] Preferably, in the technical solution, in step (2), the coordinates of the center of the wafer fixing turntable are set to (x`, y`), and the coordinate positions of the four edge points are: the first point (x1, y1), where x1 = r0╳cos45°+x`, y1 = r0╳sin45°+y`, the second point (x2, y2), where x2 = r0╳cos135°+x`, y2 = r0╳sin135°+y`, the third point (x3, y3), where x3 = r0╳cos225°+x`, y3 = r0╳sin225°+y`, and the fourth point (x4, y4), where x4 = r0╳cos315°+x`, y4 = r0╳sin315°+y`.

[0013] Preferably, in the technical solution, in step (3), the coordinates of the center position O of the wafer are set to (xc ,y c ), then the coordinates of position A are (x c ,y c +Nh1), where h1 is the vertical dimension of the grain.

[0014] Preferably, in the technical solution, in step (3), after finding the intersection of the cutting paths at position A, the low-precision camera first moves downward from the intersection of the cutting paths at position A by a distance of a grain size to obtain position A0, and uses the α-plane low-precision visual matching template to find the intersection of the cutting paths at position A0, and uses the line connecting position A and position A0 as the cutting path AA0, and calculates the angle deviation value between the cutting path AA0 and the vertical line passing through the wafer center position O according to the wafer center position O, and according to the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle to make the cutting path AA0 parallel to the vertical line, and the high-precision camera straightens the cutting path AA0 by matching with the α-plane high-precision visual matching template.

[0015] Preferably, in the technical solution, in step (3), N is calculated in the low-precision visual matching template on the α surface, N=kr0 / h1, where r0 is the wafer radius, h1 is the vertical dimension of the grain, k is the flattening coefficient, k∈[0.5, 1], and N is an integer.

[0016] Preferably, in the technical solution, in step (4), the coordinates of position B are assumed to be (x0, y0), the left side of position B is negative, and the right side of position B is positive, then the horizontal position X of all the cutting paths on the α surface is i Include X -i and X +i :

[0017] X -i =x0-it1 (1),

[0018] X +i =x0+it1 (2),

[0019] Where t1 is the horizontal dimension of the grain, i = 0, 1, 2, ..., M; M = r0 / t1;

[0020] The starting position Y of all the scribe lines on the wafer α surface i For X i At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer α surface i` For X i Where it intersects with the edge of the wafer in the vertical direction downward.

[0021] Preferably, in the technical solution, in step (5), position B' is shifted upward by M grain sizes to obtain position A', and position B' is shifted downward by M grain sizes to obtain position C'.

[0022] Preferably, in the technical solution, in step (5), the coordinates of position B' are assumed to be (x'0, y'0), the left side of position B' is negative, and the right side of position B' is positive, then the horizontal position x of all the cutting paths on the β surface is j Include X -j and X +j :

[0023] X -j =x`0-jh1 (3),

[0024] X +j =x`0+jh1 (4),

[0025] Wherein, j = 0, 1, 2, ..., N;

[0026] The starting position Y of all the scribe lines on the wafer β surface j For X j At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer β surface j` For X j Where it intersects with the edge of the wafer in the vertical direction downward.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] A low-precision camera and a high-precision camera are used to obtain a low-precision visual matching template and a high-precision visual matching template. A high-precision camera is used to repeatedly match the cutting path with the high-precision visual matching template to reduce the difference between the cutting path and the high-precision visual matching template, thereby ensuring the accuracy of the cutting path position. Description of the drawings:

[0029] Figure 1 A schematic diagram of the flow of a method for calculating the position of a cutting path by automatic wafer alignment using vision according to the present invention;

[0030] Figure 2 This is a schematic diagram of the distribution of the α-plane position A-position C of the present invention;

[0031] Figure 3 This is a schematic diagram of the α-plane cutting path of the present invention;

[0032] Figure 4 This is a schematic diagram of the distribution of the β-plane position A`-position C` of the present invention;

[0033] Figure 5 It is a schematic diagram of the β-plane cutting path of the present invention. Specific implementation method:

[0034] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0035] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0036] like Figure 1 As shown, a method for calculating the position of a cutting path by automatic wafer vision alignment, the steps of which are: (1) placing a wafer on a wafer fixing turntable, manually leveling the wafer, dividing the wafer cutting surface into an α surface and a β surface, wherein the β surface is obtained by rotating the α surface by 90°, using a low-precision camera and a high-precision camera to make a low-precision visual matching template for the α surface of the wafer and a high-precision visual matching template for the α surface of the wafer respectively, and then calibrating the difference between the low-precision visual matching template for the α surface and the high-precision visual matching template for the α surface to the intersection position of the α surface cutting path, and similarly making a low-precision visual matching template for the β surface and a high-precision visual matching template for the β surface, and then calibrating the difference between the low-precision visual matching template for the β surface and the high-precision visual matching template for the β surface to the intersection position of the β surface cutting path;

[0037] The calculation process of the difference is as follows: the low-precision camera or the high-precision camera selects feature points on the α surface of the wafer according to the wafer pattern to make the corresponding visual matching template; when the low-precision camera or the high-precision camera completes the corresponding visual matching template, the feature point is at the center of the image, and the position coordinates of the feature point are recorded, and then the low-precision camera or the high-precision camera is moved to make the image center position coincide with the intersection center position of the α surface cutting road, and the current position coordinates are subtracted from the position coordinates of the feature point to obtain the difference between the α surface low-precision visual matching template or the α surface high-precision visual matching template and the α surface cutting road intersection position; in the same way, the difference between the β surface low-precision visual matching template or the β surface high-precision visual matching template and the β surface cutting road intersection position is obtained;

[0038] (2) Calculate the positions of the four edge points of the wafer according to the wafer radius r0 and the center of the wafer fixed turntable. Assume that the coordinates of the center of the wafer fixed turntable are (x`, y`). The coordinate positions of the four edge points are: the first point (x1, y1), where x1 = r0╳cos45°+x`, y1 = r0╳sin45°+y`, the second point (x2, y2), where x2 = r0╳cos135°+x`, y2 = r0╳sin135°+y`, the third point (x3, y3), where x3 = r0╳cos225°+x`, y3 = r0╳sin225°+y`, the fourth point (x4, y4), where x4 = r0╳cos315°+x`, y4 = r0╳sin315°+y`;

[0039] Use a low-precision camera to find the precise positions of four edge points from bright to dark, verify whether the circular error composed of the precise positions of the four edge points is within the set range, and determine the wafer center position O based on the precise positions of the four edge points;

[0040] (3) Based on the wafer center position O calculated in step (2), take position A at the edge of the wafer in the wafer α plane, and set the coordinates of the wafer center position O to (x c ,y c ), then the coordinates of position A are (x c ,y c +Nh1), where h1 is the size of the grain in the vertical direction; use a low-precision camera to move spirally on the α surface of the wafer, match with the low-precision visual matching template of the α surface to find the intersection of the cutting path at position A, move down N grain size distances from the intersection of the cutting path at position A to calculate position B, calculate N in the low-precision visual matching template of the α surface, N = kr0 / h1, where r0 is the wafer radius, k is the flattening coefficient, k∈[0.5,1], k is generally 0.9, and N is an integer; then use the low-precision visual matching template of the α surface to find the intersection of the cutting path at position B, take the line connecting position A and position B as the cutting path AB, and calculate the angle deviation value between the cutting path AB and the vertical line passing through the center position O of the wafer according to the wafer center position O. According to the angle deviation value, the wafer fixed turntable drives the wafer to rotate the corresponding angle to make the cutting path AB parallel to the vertical line, and the high-precision camera matches the cutting path AB with the high-precision visual matching template of the α surface to straighten it;

[0041] Before calculating position B, the low-precision camera first moves downward from the cutting path intersection position at position A by a grain size distance to obtain position A0, and uses the α-plane low-precision visual matching template to find the cutting path intersection position at position A0. The line connecting position A and position A0 is used as cutting path AA0. According to the wafer center position O, the angle deviation value between cutting path AA0 and the vertical line passing through the wafer center position O is calculated. According to the angle deviation value, the wafer fixed turntable drives the wafer to rotate the corresponding angle to make the cutting path AA0 parallel to the vertical line. The high-precision camera matches the cutting path AA0 with the α-plane high-precision visual matching template to straighten it.

[0042] (4) Based on position A, the high-precision camera finds position C on the wafer α surface that is symmetrical to the center of position A, such as Figure 2As shown in the figure, the high-precision camera moves spirally on the wafer α surface, and finds the intersection position of the cutting road at position A and the intersection position of the cutting road at position C through the high-precision visual matching template matching of the α surface respectively, and takes the line connecting position A and position C as the cutting road AC. According to the wafer center position O, the angle deviation value between the cutting road AC and the vertical line passing through the wafer center position O is calculated. According to the angle deviation value, the wafer fixed turntable drives the wafer to rotate the corresponding angle to make the cutting road AC parallel to the vertical line; the high-precision camera repeatedly matches the cutting road AC with the α surface high-precision visual matching template until the difference between the cutting road AC and the α surface high-precision visual matching template is within the set range; the midpoint of the cutting road AC is taken as the center of the cutting road on the wafer α surface, and the midpoint of the cutting road AC coincides with position B; according to position B, the size of the grain in the horizontal direction, the wafer radius and the wafer center position O, the horizontal position X of all the cutting roads on the wafer α surface is calculated. i , start position Y i and end position Y i` ,like Figure 3 As shown;

[0043] Assume that the coordinates of position B are (x0, y0), the left side of position B is negative, and the right side of position B is positive, then the horizontal position X of all the cutting paths on the α surface is i Include X -i and X +i :

[0044] X -i =x0-it1 (1),

[0045] X +i =x0+it1 (2),

[0046] Where t1 is the horizontal dimension of the grain, i = 0, 1, 2, ..., M; M = r0 / t1;

[0047] The starting position Y of all the scribe lines on the wafer α surface i For X i At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer α surface i` For X i Where it intersects with the edge of the wafer in the vertical downward direction;

[0048] (5) Position B is rotated 90 degrees to obtain the center position B' of the wafer β-surface cutting path. Position B' is offset upward by M grain sizes to obtain position A', and position B' is offset downward by M grain sizes to obtain position C'. The β-surface low-precision visual matching template is used to match the cutting path intersection position at position A' and the cutting path intersection position at position C', respectively. The line connecting position A' and position C' is used as the cutting path A'C'. According to the wafer center position O, the angle deviation value between the cutting path A'C' and the vertical line passing through the wafer center position O is calculated. According to the angle deviation The wafer fixed turntable drives the wafer to rotate the corresponding angle to make the cutting path A`C` parallel to the vertical line; the high-precision camera repeatedly matches the cutting path A`C` with the β-surface high-precision visual matching template until the difference between the cutting path A`C` and the β-surface high-precision visual matching template is within the set range; the midpoint of the cutting path A`C` is taken as the center of the cutting path on the β-surface of the wafer, and the midpoint of the cutting path A`C` coincides with the position B`; according to the position B`, the horizontal size of the grain, the wafer radius and the wafer center position O, the horizontal position X of all the cutting paths on the β-surface of the wafer is calculated j , start position Y j and end position Y j` ,like Figure 5 As shown;

[0049] Assume that the coordinates of position B' are (x'0, y'0), the left side of position B' is negative, and the right side of position B' is positive, then the horizontal position X of all the cutting paths on the β surface is j Include X -j and X +j :

[0050] X -j =x`0-jh1 (3),

[0051] X +j =x`0+jh1 (4),

[0052] Wherein, j = 0, 1, 2, ..., N;

[0053] The starting position Y of all the scribe lines on the wafer β surface j For X j At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer β surface j` For X j Where it intersects with the edge of the wafer in the vertical direction downward.

[0054] A low-precision camera and a high-precision camera are used to obtain a low-precision visual matching template and a high-precision visual matching template. A high-precision camera is used to repeatedly match the cutting path with the high-precision visual matching template to reduce the difference between the cutting path and the high-precision visual matching template, thereby ensuring the accuracy of the cutting path position.

[0055] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for calculating the position of a cutting line by automatic wafer alignment using vision, characterized in that: The steps are as follows: (1) placing a wafer on a wafer fixing turntable, manually leveling the wafer, dividing the wafer cutting surface into an α surface and a β surface, wherein the β surface is obtained by rotating the α surface by 90°, using a low-precision camera and a high-precision camera to respectively make a low-precision visual matching template for the α surface of the wafer and a high-precision visual matching template for the α surface, and then calibrating the difference between the low-precision visual matching template for the α surface and the high-precision visual matching template for the α surface to the intersection position of the α surface cutting path, and similarly making a low-precision visual matching template for the β surface and a high-precision visual matching template for the β surface, and then calibrating the difference between the low-precision visual matching template for the β surface and the high-precision visual matching template for the β surface to the intersection position of the β surface cutting path; (2) Calculate the positions of the four edge points of the wafer based on the wafer radius r0 and the center of the wafer fixed turntable, use a low-precision camera to find the precise positions of the four edge points from bright to dark, verify whether the circular error composed of the precise positions of the four edge points is within the set range, and determine the wafer center position O based on the precise positions of the four edge points; (3) According to the wafer center position O calculated in step (2), position A located at the edge of the wafer is taken within the wafer α surface, and a low-precision camera is used to move spirally on the wafer α surface, and the cutting path intersection position at position A is found by matching with the low-precision visual matching template of the α surface, and the cutting path intersection position at position A is moved downward by N grain size distances from the cutting path intersection position at position A to calculate position B, and then the low-precision visual matching template of the α surface is used to match to find the cutting path intersection position at position B, and the line connecting position A and position B is used as the cutting path AB, and according to the wafer center position O, the angle deviation value between the cutting path AB and the vertical line passing through the wafer center position O is calculated, and according to the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle so that the cutting path AB is parallel to the vertical line, and the high-precision camera matches the cutting path AB with the high-precision visual matching template of the α surface to straighten it; (4) Based on position A, the high-precision camera finds position C on the wafer α surface that is symmetrical to the center of position A. The high-precision camera moves spirally on the wafer α surface, and finds the cutting path intersection position at position A and the cutting path intersection position at position C through α surface high-precision visual matching template matching. The line connecting position A and position C is used as the cutting path AC. Based on the wafer center position O, the angle deviation value between the cutting path AC and the vertical line passing through the wafer center position O is calculated. Based on the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle so that the cutting path AC is parallel to the vertical line. The high-precision camera repeatedly matches the cutting path AC with the high-precision visual matching template of the α surface until the difference between the cutting path AC and the high-precision visual matching template of the α surface is within the set range; the midpoint of the cutting path AC is taken as the center of the cutting path on the α surface of the wafer, and the midpoint of the cutting path AC coincides with position B; according to position B, the horizontal size of the grain, the wafer radius and the wafer center position O, the horizontal position X of all the cutting paths on the α surface of the wafer is calculated i , start position Y i and end position Y i` ; (5) Rotate position B 90 degrees to obtain the center position B' of the wafer β-surface cutting path. Calculate position A' and position C' upward and downward respectively based on position B'. Use the β-surface low-precision visual matching template to match the cutting path intersection position at position A' and the cutting path intersection position at position C'. Take the line connecting position A' and position C' as the cutting path A'C'. Calculate the angle deviation between the cutting path A'C' and the vertical line passing through the wafer center position O according to the wafer center position O. According to the angle deviation value, the wafer is fixed on the turntable. Drive the wafer to rotate the corresponding angle to make the cutting path A`C` parallel to the vertical line; the high-precision camera repeatedly matches the cutting path A`C` with the high-precision visual matching template of the β surface until the difference between the cutting path A`C` and the high-precision visual matching template of the β surface is within the set range; take the midpoint of the cutting path A`C` as the center of the cutting path on the β surface of the wafer, and the midpoint of the cutting path A`C` coincides with the position B`; according to the position B`, the horizontal size of the grain, the wafer radius and the wafer center position O, calculate the horizontal position X of all the cutting paths on the β surface of the wafer j , start position Y j and end position Y j` .

2. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (1), a low-precision camera or a high-precision camera selects feature points on the α surface of the wafer according to the wafer pattern to make a corresponding visual matching template; when the low-precision camera or the high-precision camera completes the corresponding visual matching template, the feature point is at the center of the image, and the position coordinates of the feature point are recorded. Then, the low-precision camera or the high-precision camera is moved so that the center position of the image coincides with the center position of the intersection of the α surface cutting path, and the current position coordinates are subtracted from the position coordinates of the feature point to obtain the difference between the low-precision visual matching template of the α surface or the high-precision visual matching template of the α surface and the intersection position of the α surface cutting path; in the same way, the difference between the low-precision visual matching template of the β surface or the high-precision visual matching template of the β surface and the intersection position of the β surface cutting path is obtained.

3. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (2), assume that the coordinates of the center of the wafer fixing turntable are (x`, y`), and the coordinate positions of the four edge points are: the first point (x1, y1), where x1 = r0╳cos45°+x`, y1 = r0╳sin45°+y`, the second point (x2, y2), where x2 = r0╳cos135°+x`, y2 = r0╳sin135°+y`, the third point (x3, y3), where x3 = r0╳cos225°+x`, y3 = r0╳sin225°+y`, and the fourth point (x4, y4), where x4 = r0╳cos315°+x`, y4 = r0╳sin315°+y`.

4. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (3), let the coordinates of the wafer center position O be (x c ,y c ), then the coordinates of position A are (x c ,y c +Nh1), where h1 is the vertical dimension of the grain.

5. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (3), after finding the intersection of the cutting paths at position A, the low-precision camera first moves downward from the intersection of the cutting paths at position A by a distance of a grain size to obtain position A0, and uses the α-plane low-precision visual matching template to find the intersection of the cutting paths at position A0. The line connecting position A and position A0 is used as the cutting path AA0, and according to the wafer center position O, the angle deviation value between the cutting path AA0 and the vertical line passing through the wafer center position O is calculated. According to the angle deviation value, the wafer fixed turntable drives the wafer to rotate a corresponding angle so that the cutting path AA0 is parallel to the vertical line, and the high-precision camera straightens the cutting path AA0 by matching with the α-plane high-precision visual matching template.

6. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (3), N is calculated in the low-precision visual matching template of the α surface, N = kr0 / h1, where r0 is the wafer radius, k is the flattening coefficient, k∈[0.5, 1], and N is an integer.

7. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (4), let the coordinates of position B be (x0, y0), the left side of position B is negative, and the right side of position B is positive, then the horizontal position X of all the cutting paths on the α surface is i Include X -i and X +i : X -i =x0-it1 (1), X +i =x0+it1 (2), Where t1 is the horizontal dimension of the grain, i = 0, 1, 2, ..., M; M = r0 / t1; The starting position Y of all the scribe lines on the wafer α surface i For X i At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer α surface i` For X i Where it intersects with the edge of the wafer in the vertical direction downward.

8. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (5), position B' is deviated upward by M grain sizes to obtain position A', and position B' is deviated downward by M grain sizes to obtain position C'.

9. The method for calculating the position of the cutting line by automatic wafer alignment by vision according to claim 1, characterized in that: In step (5), let the coordinates of position B' be (x'0, y'0), the left side of position B' is negative, and the right side of position B' is positive, then the horizontal position X of all the cutting paths on the β surface is j Include X -j and X +j : X -j =x`0-jh1 (3), X +j =x`0+jh1 (4), Wherein, j = 0, 1, 2, ..., N; The starting position Y of all the scribe lines on the wafer β surface j For X j At the intersection of the vertical direction and the wafer edge, the end position Y of all the cutting paths on the wafer β surface j` For X j Where it intersects with the edge of the wafer in the vertical direction downward.

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