Wafer detection parameter determination method

Abstract

The invention relates to a wafer detection parameter determination method. The method comprises the following steps: determining an expected coordinate of a next crystal grain in a machine coordinate system according to a reference coordinate of a reference crystal grain in the machine coordinate system; controlling the next crystal grain to be in the center of the camera scanning view according to the expected coordinate, calculating the real coordinate of the next crystal grain in the machine coordinate system, and updating the crystal grain interval and the placement angle of the to-be-detected wafer according to the real coordinate; and according to the reference coordinate and the total moving distance of the machine, recalculating a new expected coordinate of the next crystal grain, and circularly executing the process of updating the crystal grain interval and the placement angle of the to-be-detected wafer until the total moving distance of the machine meets a preset condition. And determining the crystal grain interval and the placement angle obtained by the last update as the real crystal grain interval and the real placement angle of the wafer to be detected. By adopting the method, the grain spacing and the wafer placement angle can be accurately calculated.

Description

Technical Field

[0001] The present application relates to the technical field of wafer detection, and particularly to a method for determining wafer detection parameters. Background Art

[0002] Wafer detection is a very important step in the semiconductor manufacturing process, mainly used to detect the electrical properties and surface defects of wafers to ensure that the quality of wafers meets the standards, thereby improving the reliability and stability of products.

[0003] Wafer detection requires calculating the shooting path required for the detection process. In related technologies, the shooting path is usually calculated based on wafer detection parameters, and the main parameters involved include the grain spacing in the wafer and the placement angle of the wafer on the machine platform; among them, the grain spacing is used to determine a suitable shooting field of view to ensure that the number of grains in each shooting field of view is the same, and the placement angle is used to ensure that the position of the wafer in each captured image remains the same.

[0004] Based on this, before wafer detection, how to accurately calculate the grain spacing and wafer placement angle has become a technical problem to be solved urgently. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a method for determining wafer detection parameters that can accurately calculate the grain spacing and wafer placement angle.

[0006] In a first aspect, an embodiment of the present application provides a method for determining wafer detection parameters, including:

[0007] When the wafer to be detected is fixed on the machine platform and the reference grain in the wafer to be detected is at the center of the camera scanning field of view of the machine platform, determine the expected coordinates of the next grain in the machine platform coordinate system according to the reference coordinates of the reference grain in the machine platform coordinate system;

[0008] Control the next grain to be at the center of the camera scanning field of view according to the expected coordinates, and calculate the actual coordinates of the next grain in the machine platform coordinate system. Update the grain spacing and placement angle of the wafer to be detected according to the actual coordinates;

[0009] According to the reference coordinates and the total moving distance of the machine platform, recalculate the expected coordinates of the new next grain, and loop to execute the process of updating the grain spacing and placement angle of the wafer to be detected until the total moving distance of the machine platform meets the preset conditions, and determine the finally updated grain spacing and placement angle as the actual grain spacing and actual placement angle of the wafer to be detected.

[0010] In one of the embodiments, determining the expected coordinates of the next grain in the machine platform coordinate system according to the reference coordinates of the reference grain in the machine platform coordinate system includes:

[0011] Obtain the maximum number of rows of grains that can be accommodated and the maximum number of columns of grains that can be accommodated within the effective field of view of the camera, the initial grain spacing, and the initial placement angle;

[0012] Based on the reference coordinates, the maximum number of rows of grains that can be accommodated, the maximum number of columns of grains that can be accommodated, the initial grain spacing, and the initial placement angle, determine the expected coordinates of the next grain in the machine table coordinate system.

[0013] In one embodiment, obtaining the maximum number of rows of grains that can be accommodated and the maximum number of columns of grains that can be accommodated within the effective field of view of the camera, the initial grain spacing, and the initial placement angle includes:

[0014] Obtain the starting point grain in the wafer template map of the wafer to be detected; the wafer template map is obtained by splicing multiple grain maps scanned according to a preset scanning trajectory;

[0015] Taking the upper right corner of the starting point grain as the starting point for grain search, slide a distance equal to the width of one grain along the horizontal axis direction to search for the horizontally matching grains that match the pre-selected grain features until the preset horizontal search stop condition is met, and obtain the number of horizontally matching grains and the pixel coordinates of each horizontally matching grain; and, taking the lower left corner of the starting point grain as the starting point for grain search, slide a distance equal to the height of one grain along the vertical axis direction to search for the vertically matching grains that match the grain features until the preset vertical search stop condition is met, and obtain the number of vertically matching grains and the pixel coordinates of each vertically matching grain;

[0016] Determine the maximum number of columns of grains that can be accommodated according to the number of horizontally matching grains, determine the maximum number of rows of grains that can be accommodated according to the number of vertically matching grains, and determine the initial grain spacing and the initial placement angle according to the pixel coordinates of each horizontally matching grain and the pixel coordinates of each vertically matching grain.

[0017] In one embodiment, determining the initial grain spacing and the initial placement angle according to the pixel coordinates of each horizontally matching grain and the pixel coordinates of each vertically matching grain includes:

[0018] According to the pixel coordinates of each horizontally matching grain, obtain the pixel coordinates of the first horizontally matching grain and the pixel coordinates of the last horizontally matching grain, and according to the pixel coordinates of each vertically matching grain, obtain the pixel coordinates of the first vertically matching grain and the pixel coordinates of the last vertically matching grain;

[0019] Determine the candidate grain spacing and the candidate placement angle according to the pixel coordinates of the first horizontally matching grain, the pixel coordinates of the last horizontally matching grain, the pixel coordinates of the first vertically matching grain, and the pixel coordinates of the last vertically matching grain;

[0020] Determine the initial grain interval according to the candidate grain interval and the pixel pulse coefficient, and determine the initial placement angle according to the candidate placement angle and the pixel pulse coefficient.

[0021] In one embodiment, the next grain is a valid grain; calculate the true coordinates of the next grain in the machine tool coordinate system, including:

[0022] Obtain the position deviation between the reference grain and the next grain;

[0023] Calibrate the expected coordinates of the next grain according to the position deviation between the reference grain and the next grain, and determine the calibrated coordinates as the true coordinates of the next grain.

[0024] In one embodiment, according to the grain map taken when the next grain is at the center of the camera scanning field of view, search for the matching grains that match the pre-framed grain features, and obtain the pixel coordinates of the matching grains;

[0025] Determine the pixel deviation coordinates of the matching grains relative to the image center point coordinates of the grain map according to the pixel coordinates of the matching grains and the image center point coordinates of the grain map;

[0026] Convert the pixel deviation coordinates according to the pixel pulse coefficient to obtain the position deviation between the reference grain and the next grain.

[0027] In one embodiment, the next grain is an invalid grain; calculate the true coordinates of the next grain in the machine tool coordinate system, including:

[0028] If there are valid grains in the grain map when the next grain is at the center of the camera scanning field of view, determine the true coordinates of the next grain according to the grain map and the expected coordinates of the next grain;

[0029] If there are no valid grains in the grain map, control the machine tool to move to re-obtain the grain map, and determine the true coordinates of the next grain according to the re-obtained grain map and the expected coordinates of the next grain.

[0030] In one embodiment, determine the true coordinates of the next grain according to the grain map and the expected coordinates of the next grain, including:

[0031] Search for valid grains that match the pre-framed grain features in the grain map, and obtain the pixel coordinates of the valid grains;

[0032] Determine the true coordinates of the valid grains in the machine tool coordinate system according to the pixel coordinates of the valid grains, the image center coordinates of the grain map, the pixel pulse coefficient and the expected coordinates of the next grain;

[0033] Determine the true coordinates of the next grain based on the true coordinates of the effective grain, the number of grains between the effective grain and the next grain, the initial grain spacing, and the initial placement angle.

[0034] In one embodiment, to determine the true coordinates of the effective grain in the machine coordinate system based on the pixel coordinates of the effective grain, the image center coordinates of the grain map, the pixel pulse coefficient, and the expected coordinates of the next grain, it includes:

[0035] Determine the true deviation coordinates of the effective grain relative to the image center point according to the pixel coordinates of the effective grain, the image center coordinates of the grain map, and the pixel pulse coefficient;

[0036] Determine the true coordinates of the effective grain according to the sum between the true deviation coordinates and the expected coordinates of the next grain.

[0037] In one embodiment, to determine the true coordinates of the next grain based on the true coordinates of the effective grain, the number of grains between the effective grain and the next grain, the initial grain spacing, and the initial placement angle, it includes:

[0038] Determine the true distance between the effective grain and the next grain according to the number of grain intervals between the effective grain and the next grain, the initial grain spacing, and the initial placement angle;

[0039] Determine the true coordinates of the next grain according to the difference between the true coordinates of the effective grain and the true distance.

[0040] In one embodiment, controlling the machine to move to re-acquire the grain map includes:

[0041] In the eight-connected domain direction centered on the current field of view, after moving the machine by the grain distance of one field of view size, control the camera to scan the image to obtain the re-acquired grain map.

[0042] In one embodiment, to determine the true coordinates of the next grain according to the re-acquired grain map and the expected coordinates of the next grain, it includes:

[0043] Search for the effective grain that matches the pre-framed grain feature in the re-acquired grain map and obtain the pixel coordinates of the effective grain;

[0044] Determine the true coordinates of the effective grain in the machine coordinate system according to the pixel coordinates of the effective grain, the image center coordinates of the grain map, the pixel pulse coefficient, and the expected coordinates of the next grain;

[0045] Determine the true coordinates of the next grain according to the true coordinates of the effective grain, the initial grain spacing, the maximum number of grains that can be accommodated in a row within the effective field of view of the camera, and the maximum number of grains that can be accommodated in a column.

[0046] In one embodiment, determining the true coordinates of the next grain based on the true coordinates of the valid grain, the initial grain spacing, the maximum number of grain rows and the maximum number of grain columns that can be accommodated within the effective field of view of the camera includes:

[0047] Determining the true coordinates of the mapped grain in the machine coordinate system based on the true coordinates of the valid grain, the number of grain spacings between the valid grain and the next grain, the initial grain spacing, and the initial placement angle; the mapped grain is the grain in the re-acquired grain map that has the same pixel coordinates as the next grain within the original field of view;

[0048] Determining the moving distance of the machine based on the initial grain spacing, the maximum number of grain rows and the maximum number of grain columns that can be accommodated;

[0049] Determining the true coordinates of the next grain based on the difference between the true coordinates of the mapped grain and the moving distance.

[0050] In one embodiment, updating the grain spacing and the placement angle of the wafer to be detected based on the true coordinates includes:

[0051] Obtaining the true coordinates of the penultimate next grain in the machine coordinates; the penultimate next grain is the adjacent next grain before the next grain;

[0052] Determining the number of grain spacings between the penultimate next grain and the next grain based on the maximum number of grain rows and the maximum number of grain columns that can be accommodated within the effective field of view of the camera, and the number of field spacings between the penultimate next grain and the next grain;

[0053] Determining the true distance between the penultimate next grain and the next grain based on the true coordinates of the penultimate next grain and the true coordinates of the next grain;

[0054] Updating the grain spacing and the placement angle based on the number of grain spacings and the true distance.

[0055] In one embodiment, the true distance includes the true distance in the horizontal axis direction and the true distance in the vertical axis direction; the number of grain spacings includes the number of grain spacings in the horizontal axis direction and the number of grain spacings in the vertical axis direction; updating the grain spacing based on the number of grain spacings and the true distance includes:

[0056] Determining the grain spacing in the horizontal axis direction based on the ratio between the true distance in the horizontal axis direction and the number of grain spacings in the horizontal axis direction;

[0057] Determining the grain spacing in the vertical axis direction based on the ratio between the true distance in the vertical axis direction and the number of grain spacings in the vertical axis direction;

[0058] Determining the updated grain spacing by taking the grain spacing in the horizontal axis direction and the grain spacing in the vertical axis direction.

[0059] In one embodiment, the true distance includes the true distance in the horizontal axis direction and the true distance in the vertical axis direction; the number of grain intervals includes the number of grain intervals in the horizontal axis direction and the number of grain intervals in the vertical axis direction; updating the placement angle according to the number of grain intervals and the true distance coordinates includes:

[0060] Determining the offset distance in the horizontal axis direction according to the ratio between the true distance in the horizontal axis direction and the number of grain intervals in the horizontal axis direction;

[0061] Determining the offset distance in the vertical axis direction according to the ratio between the true distance in the vertical axis direction and the number of grain intervals in the vertical axis direction;

[0062] Determining the offset distance in the horizontal axis direction and the offset distance in the vertical axis direction as the updated placement angle.

[0063] In one embodiment, the method further includes:

[0064] Controlling the feature point in the wafer to be detected to be at the center of the camera scanning field of view according to the coordinates of the taught feature point in the machine tool coordinate system; the taught feature point is a reference point for positioning the wafer to be detected;

[0065] Determining the true coordinates of the feature point in the wafer to be detected in the machine tool coordinate system according to the currently scanned grain map;

[0066] Determining the reference coordinates of the reference grain according to the true coordinates of the feature point in the wafer to be detected.

[0067] In one embodiment, determining the true coordinates of the feature point in the machine tool coordinate system according to the currently scanned grain map includes:

[0068] Searching for a matching feature point that matches the taught feature point in the grain map, and obtaining the pixel coordinates of the matching feature point;

[0069] Determining the true deviation coordinates of the matching feature point relative to the image center point according to the pixel coordinates of the matching feature point, the image center point coordinates of the grain map, and the pixel pulse coefficient;

[0070] Determining the true coordinates of the feature point according to the sum between the true deviation coordinates and the coordinates of the taught feature point.

[0071] In one embodiment, determining the reference coordinates of the reference grain according to the true coordinates of the feature point in the wafer to be detected includes:

[0072] Controlling the feature point to be at the center of the camera scanning field of view according to the true coordinates of the feature point, and controlling the camera to scan the image to obtain the grain map;

[0073] If the grain map includes valid grains, determine the reference coordinates of the reference grain according to the grain map and the true coordinates of the feature points;

[0074] If the grain map does not include valid grains, control the machine stage to move to re-acquire the grain map, and determine the reference coordinates of the reference grain according to the re-acquired grain map.

[0075] In one embodiment, determining the reference coordinates of the reference grain according to the grain map and the true coordinates of the feature points includes:

[0076] Search for a matching grain in the grain map that matches the pre-selected grain feature, and obtain the pixel coordinates of the matching grain;

[0077] Determine the true deviation coordinates of the matching grain relative to the image center point according to the pixel coordinates of the matching grain, the image center coordinates of the grain map, and the pixel pulse coefficient;

[0078] Determine the reference coordinates of the reference grain according to the sum between the true deviation coordinates and the true coordinates of the feature points.

[0079] In one embodiment, controlling the machine stage to move to re-acquire the grain map includes:

[0080] Control the machine stage to move in the horizontal axis direction of the feature point, and when the machine stage moves to a preset distance from the true coordinates of the feature point, control the camera to scan the image to obtain the re-acquired grain map; the preset distance is the distance of a preset number of field widths.

[0081] In one embodiment, determining the reference coordinates of the reference grain according to the re-acquired grain map includes:

[0082] Determine the true coordinates of the field of view center of the re-acquired grain map in the machine stage coordinate system according to the sum between the true coordinates of the feature point and the preset distance;

[0083] Search for a matching grain in the re-acquired grain map that matches the pre-selected grain feature, and obtain the pixel coordinates of the matching grain;

[0084] Determine the true deviation coordinates of the matching grain relative to the image center point according to the pixel coordinates of the matching grain, the image center point coordinates of the re-acquired grain map, and the pixel pulse coefficient;

[0085] Determine the reference coordinates of the reference grain according to the sum between the true deviation coordinates and the true coordinates of the field of view center.

[0086] In a second aspect, the embodiments of the present application further provide a wafer detection parameter determination device, including:

[0087] An expected coordinate determination module, configured to determine the expected coordinates of the next die in the machine platform coordinate system according to the reference coordinates of a reference die in the machine platform coordinate system when the die to be detected in the wafer to be detected is fixed on the machine platform and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine platform;

[0088] A parameter update module, configured to control the next die to be at the center of the camera scanning field of view according to the expected coordinates, calculate the actual coordinates of the next die in the machine platform coordinate system, and update the die interval and placement angle of the wafer to be detected according to the actual coordinates;

[0089] A parameter determination module, configured to recalculate the expected coordinates of the new next die according to the reference coordinates and the total movement distance of the stage, and loop to execute the process of updating the die interval and placement angle of the wafer to be detected until the total movement distance of the stage meets the preset condition, and determine the die interval and placement angle obtained by the last update as the actual die interval and actual placement angle of the wafer to be detected.

[0090] In a third aspect, an embodiment of the present application further provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of the method in any one of the embodiments in the first aspect are implemented.

[0091] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method in any one of the embodiments in the first aspect are implemented.

[0092] In a fifth aspect, an embodiment of the present application further provides a computer program product, including a computer program, and when the computer program is executed by a processor, the steps of the method in any one of the embodiments in the first aspect are implemented.

[0093] The method for determining wafer detection parameters provided by the embodiments of the present application first determines the expected coordinates of the next die in the machine platform coordinate system according to the reference coordinates of the reference die in the machine platform coordinate system when the reference die in the wafer to be detected is fixed on the machine platform and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine platform. Then, according to the expected coordinates, the next die is controlled to be at the center of the camera scanning field of view, and the actual coordinates of the next die in the machine platform coordinate system are calculated. According to the actual coordinates, the die pitch and placement angle of the wafer to be detected are updated. After that, according to the reference coordinates and the total movement distance of the machine platform, the expected coordinates of the new next die are recalculated, and the process of updating the die pitch and placement angle of the wafer to be detected is cyclically executed until the total movement distance of the machine platform meets the preset conditions, and the die pitch and placement angle obtained by the last update are determined as the actual die pitch and actual placement angle of the wafer to be detected. In this method, when calculating the wafer detection parameters, the expected coordinates of the next die are first calculated, and then the expected coordinates of the next die are calibrated by moving the machine platform to scan the image, the actual coordinates of the next die are calculated, and the die pitch and placement angle of the wafer to be detected are updated according to the actual coordinates. Equivalently, scanning is combined with movement, and the die pitch and placement angle are updated by calculating, verifying and correcting while scanning, making the calculated die pitch and placement angle more accurate; and by continuously moving the machine platform, the actual coordinates of the new next die are recalculated, and the die pitch and placement angle are cyclically updated, which is equivalent to continuously repeating the process of calculation, verification and correction to cyclically update the die pitch and placement angle, further improving the calculation accuracy of the die pitch and placement angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0095] Figure 1 It is a schematic flowchart of the method for determining wafer detection parameters in an embodiment;

[0096] Figure 2 It is a schematic flowchart of determining the expected coordinates of the next die in an embodiment;

[0097] Figure 3 It is a schematic diagram of the starting die in an embodiment;

[0098] Figure 4 It is a schematic diagram of searching for the starting point in an embodiment;

[0099] Figure 5 Schematic diagram of a reference grain and the next grain in an embodiment;

[0100] Figure 6 Schematic diagram of a new next grain in an embodiment;

[0101] Figure 7 Flow schematic diagram for calculating the true coordinates of the next grain in an embodiment;

[0102] Figure 8 Flow schematic diagram for calculating the true coordinates of the next grain in another embodiment;

[0103] Figure 9 Schematic diagram for searching grains in 8 - connected domain directions in an embodiment;

[0104] Figure 10 Flow schematic diagram for updating the grain interval and placement angle in an embodiment;

[0105] Figure 11 Flow schematic diagram for determining the reference coordinates in an embodiment;

[0106] Figure 12a Schematic diagram for searching grains in 4 - connected domain directions in an embodiment;

[0107] Figure 12b Schematic diagram of the search direction of the next grain in an embodiment;

[0108] Figure 13 Schematic diagram of the structure of a wafer detection parameter determination device in an embodiment. Detailed implementation manners

[0109] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0110] The technical background of the embodiments of the present application will be described first below.

[0111] Wafer detection is a very important step in the semiconductor manufacturing process, mainly used to detect the electrical properties and surface defects of wafers to ensure that the quality of the wafers meets the standards, thereby improving the reliability and stability of the products.

[0112] In the related art, the detection of the wafer disk requires calculating the shooting path. Since the intervals between the wafers are relatively fixed, the shooting path needs to be adjusted according to the intervals and sizes of the wafers to obtain a suitable shooting field of view, ensuring that the number of die in each shooting field of view is the same. Additionally, due to the angular deviation in the placement of the wafer disk, the corresponding relationship between the angle and the shooting path needs to be fully considered to ensure that the positions of the wafers in the images obtained from each shooting are consistent. An algorithm is used to achieve a perfect detection effect. However, traditional methods suffer from various problems, such as insufficient accuracy, inability to evaluate the calculated angle, lack of robustness, or high operation complexity. In traditional methods, the intervals and angles are calculated only through images. Due to factors such as the limitation of the image field of view and the size of the wafers, the calculated accuracy is not high, and error accumulation is likely to occur. Alternatively, multiple points need to be taught, and the movement of the machine tool is coordinated with the camera for calculation, which is too cumbersome, increases the operation difficulty, and raises the probability of operation errors. Moreover, all of the above methods lack robustness and cannot handle adverse situations, such as damaged mark points. Without evaluating the calculation results, incorrect results may be accepted, failing to meet the expected situation.

[0113] Based on this, the present application provides a method for determining wafer detection parameters. When calculating the wafer detection parameters, the expected coordinates of the next die are first calculated, and then the machine tool is moved to scan the image to calibrate the expected coordinates of the next die, calculate the true coordinates of the next die, and update the die interval and placement angle of the wafer to be detected based on the true coordinates. In other words, by combining scanning and movement, and using a method of calculating, verifying, and correcting simultaneously, the die interval and placement angle are updated, making the calculated die interval and placement angle more accurate. Moreover, by continuously moving the machine tool, the true coordinates of the new next die are recalculated, and the die interval and placement angle are cyclically updated, which is equivalent to continuously repeating the process of calculation, verification, and correction to further improve the calculation accuracy of the die interval and placement angle. Of course, the technical solutions provided in the embodiments of the present application are not limited to solving only the above problems, and there are other technical effects, which can be specifically seen in the following embodiments.

[0114] It should be noted that the beneficial effects or the technical problems solved by the embodiments of the present application are not limited to this one, and there may be other implicit or related problems, which can be specifically seen in the description of the following embodiments.

[0115] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0116] In an exemplary embodiment, as Figure 1 shown, a method for determining wafer detection parameters is provided. Taking the application of this method to a server as an example, it includes the following steps 201 to 203. Among them:

[0117] S201. When the wafer to be detected is fixed on the machine stage and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine stage, determine the expected coordinates of the next die in the machine stage coordinate system according to the reference coordinates of the reference die in the machine stage coordinate system.

[0118] Among them, the reference die is a representative standard die selected when calculating the die pitch and wafer angle. It can be understood that the reference die is usually complete and defect-free to ensure the accuracy and reliability of the calculation results. The next die refers to any die in the wafer to be detected except the reference die, which is used to calculate the die pitch and placement angle of the wafer to be detected in combination with the reference coordinates of the reference die.

[0119] After the wafer to be detected is fixed on the machine stage, control the machine stage to move so that the reference die in the wafer to be detected is within the camera scanning field of view. At this time, it is necessary to calculate the expected coordinates of the next die in the machine stage coordinate system according to the reference coordinates of the reference die in the machine stage coordinate system. Among them, when calculating the expected coordinates of the next die, it is necessary to calculate based on the selection method of the next die. For example, if the next die is selected with multiple dies spaced from the reference die, the expected coordinates of the next die can be calculated based on the number of spaced dies, the initial die pitch, and the reference coordinates of the reference die.

[0120] Exemplarily, the reference coordinates of the reference die in the machine stage coordinate system can be calculated through the die map scanned by the camera. For example, when the reference die is at the center of the camera scanning field of view, control the camera to collect the die map of the current field of view, determine the pixel coordinates of the reference die in this die map, and then, according to the conversion relationship between the pixel coordinates and the real coordinates, that is, perform coordinate conversion on the pixel coordinates of the reference die to obtain the reference coordinates of the reference die in the machine stage coordinate system.

[0121] S202. Control the next die to be at the center of the camera scanning field of view according to the expected coordinates, calculate the real coordinates of the next die in the machine stage coordinate system, and update the die pitch and placement angle of the wafer to be detected according to the real coordinates.

[0122] In the embodiment of the present application, after determining the expected coordinates of the next die, control the next die to be at the center of the camera scanning field of view according to the expected coordinates of the next die. For example, control the machine stage to move to the position of the expected coordinates of the next die so that the next die is at the center of the camera scanning field of view.

[0123] After moving the machine stage to the specified position, calculate the true coordinates of the next die in the machine stage coordinate system. Exemplarily, after the machine stage moves to the position of the expected coordinates of the next die, control the camera to collect the die image, and determine the deviation between the expected coordinates and the true coordinates of the next die based on the die image. Then, according to the deviation between the expected coordinates and the true coordinates of the next die and the expected coordinates of the next die, determine the true coordinates of the next die.

[0124] Further, after calculating the true coordinates of the next die, update the die pitch and placement angle of the wafer to be detected according to the true coordinates of the next die. Exemplarily, calculate the true distance between the next die and the reference die according to the true coordinates of the next die and the reference coordinates of the reference die. Then, based on the true distance between the next die and the reference die and the number of die pitches between the next die and the reference die, determine the updated die pitch and the updated placement angle.

[0125] S203, according to the reference coordinates and the total movement distance of the machine stage, recalculate the expected coordinates of the new next die, and loop to execute the process of updating the die pitch and placement angle of the wafer to be detected until the total movement distance of the machine stage meets the preset condition, and determine the die pitch and placement angle obtained by the last update as the true die pitch and true placement angle of the wafer to be detected.

[0126] After updating the die pitch and placement angle based on the first next die, continue to calculate the expected coordinates of the second next die, and update the die pitch and placement angle again based on the second next die. Among them, the expected coordinates of the second next die are determined based on the reference coordinates of the reference die and the total movement distance of the machine stage. Then, continuously repeat the above update process of the next die (that is, calculate the expected coordinates of the third next die, the expected coordinates of the fourth next die... in turn), and at the same time, each time the expected coordinates of the next die are calculated, update the die pitch and placement angle. Until the total movement distance of the machine stage meets the preset condition, determine the die pitch and placement angle obtained by the last update as the true die pitch and true placement angle of the wafer to be detected.

[0127] Among them, each time the grain interval and the placement angle are updated, they are updated based on the true coordinates of the current next grain and the true coordinates of the previous next grain of the current next grain. For example, taking the first next grain as grain A and the second next grain as grain B, if the current next grain is grain B, then when updating the grain interval and the placement angle, it is necessary to determine the true distance between grain B and grain A according to the difference between the true coordinates of grain B and the true coordinates of grain A, and determine the updated grain interval and placement angle according to the true distance and the number of grain intervals between grain B and grain A.

[0128] In the embodiment of the present application, after determining the true grain interval and the true placement angle of the wafer to be detected, when performing wafer detection on the wafer to be detected, the shooting path during detection can be calculated according to the true grain interval and the true placement angle of the wafer to be detected, and wafer detection is performed based on the shooting path. Among them, the method of calculating the shooting path can be to calculate the true coordinates of each grain in the machine tool coordinate system according to the true grain interval and the true placement angle of the wafer to be detected, and then calculate in groups with multiple grains. For example, taking 2×2 grains as a group, according to the true coordinates, the true grain interval and the true placement angle of each grain in the machine tool coordinate system, the center point coordinates of each group of grains are determined, and the center point coordinates of multiple groups of grains can form the shooting path, and different movement trajectories can be adopted for wafer detection according to the shooting path. For example, the s-shaped movement trajectory is adopted to perform wafer detection on the wafer to be detected according to the shooting path.

[0129] The method for determining wafer detection parameters provided by the embodiments of the present application first determines the expected coordinates of the next die in the machine platform coordinate system according to the reference coordinates of the reference die in the machine platform coordinate system when the reference die in the wafer to be detected is fixed on the machine platform and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine platform. Then, according to the expected coordinates, the next die is controlled to be at the center of the camera scanning field of view, and the actual coordinates of the next die in the machine platform coordinate system are calculated. According to the actual coordinates, the die interval and placement angle of the wafer to be detected are updated. After that, according to the reference coordinates and the total moving distance of the machine platform, the expected coordinates of the new next die are recalculated, and the process of updating the die interval and placement angle of the wafer to be detected is cyclically executed until the total moving distance of the machine platform meets the preset conditions. The die interval and placement angle obtained from the last update are determined as the actual die interval and actual placement angle of the wafer to be detected. In this method, when calculating the wafer detection parameters, first calculate the expected coordinates of the next die, and then calibrate the expected coordinates of the next die by moving the machine platform to scan the image, calculate the actual coordinates of the next die, and update the die interval and placement angle of the wafer to be detected according to the actual coordinates. Equivalently, by combining scanning and movement, and using the method of calculating, verifying and correcting while scanning, the die interval and placement angle are updated, making the calculated die interval and placement angle more accurate. And by continuously moving the machine platform, recalculating the actual coordinates of the new next die, and cyclically updating the die interval and placement angle, it is equivalent to continuously repeating the process of calculating, verifying and correcting to cyclically update the die interval and placement angle, further improving the calculation accuracy of the die interval and placement angle.

[0130] Based on the above embodiments, an embodiment for the process of determining the expected coordinates of the next die is provided for description.

[0131] In an exemplary embodiment, as Figure 2 shown, determining the expected coordinates of the next die in the machine platform coordinate system according to the reference coordinates of the reference die in the machine platform coordinate system includes:

[0132] S301, obtain the maximum number of die rows and maximum number of die columns that can be accommodated within the effective field of view of the camera, the initial die interval, and the initial placement angle.

[0133] In one embodiment, obtaining the maximum number of die rows and maximum number of die columns that can be accommodated within the effective field of view of the camera, the initial die interval, and the initial placement angle includes the following steps:

[0134] Step 1, obtain the starting die in the wafer template map of the wafer to be detected; the wafer template map is obtained by splicing a plurality of die maps scanned according to a preset scanning trajectory.

[0135] The starting point grain is the grain selected in the modeling process. In the embodiments of the present application, a modeling process is required to select the grain feature and establish a detection template process.

[0136] The pulse spacing in the X direction of the grain is represented by dX, and the pulse offset in the Y direction caused by the inclination of the crystal disc for every dX distance is represented by dxY. The pulse spacing in the Y direction of the grain is represented by dY, and the pulse offset in the X direction caused by the inclination of the crystal disc for every dY distance is represented by dyX. Among them, dX and dY are the grain spacings of the wafer to be detected, and dxY and dyX are the placement angles of the wafer to be detected.

[0137] According to the S-shaped movement trajectory, the wafer to be detected is scanned to obtain N*N images, and an image stitching technique is used to synthesize a template image to obtain the wafer template image of the wafer to be detected. Among them, for the movement trajectory requirements, the images taken for each movement distance must ensure that there is an overlapping area between adjacent images to meet the requirement that the template image is larger than the camera's field of view.

[0138] Based on the wafer template image, an algorithm template is established on the wafer template image. First, the size range of the grain is selected. The grains within the range should ensure clear features and be free from the influence of dirt, and there are no other grain features within the selected range. Secondly, the grain feature is selected. This feature is the unique feature of the grain and is an important basis for the algorithm to identify the grain. And the grain feature is usually within the size range of the grain. Taking this grain as the starting point grain W1, the position of this grain in the image coordinate system is (W1_X, W1_Y). Figure 3 For example, W1 is the starting point grain, the large dashed box is the selected size range of the grain, and the small dashed box is the selected grain feature.

[0139] Step 2: Taking the upper right corner of the starting point grain as the starting point of grain search, slide a distance equal to the width of one grain along the horizontal axis to search for the horizontally matching grains that match the pre-selected grain feature until the preset horizontal search stop condition is met, and obtain the number of horizontally matching grains and the pixel coordinates of each horizontally matching grain; and taking the lower left corner of the starting point grain as the starting point of grain search, slide a distance equal to the height of one grain along the vertical axis to search for the vertically matching grains that match the grain feature until the preset vertical search stop condition is met, and obtain the number of vertically matching grains and the pixel coordinates of each vertically matching grain.

[0140] As Figure 4 shown, the upper right corner of the starting point grain is point a, and the lower left corner of the starting point grain is point b.

[0141] In the embodiment of the present application, the upper right corner of the W1 grain is used as the starting point for grain search. Slide a distance of one grain width W1_W along the X direction, and call the Opencv template matching function MatchTemplatemo within the search range to search for grain features. The nth horizontal axis matching grain found in this direction is WXn, and its pixel coordinates are (WXn_X, WXn_Y). Each subsequent slide starts from the upper right corner of the WXn grain, slides a distance of W1_W, and searches for grain features until the condition (WXn_X - W1_X) > image width is met, obtaining the pixel coordinates of all the horizontal axis matching grains and the number of horizontal axis matching grains.

[0142] Using the lower left corner of the W1 grain as the starting point for grain search, slide a distance of one grain height W1_H along the Y direction, and call the Opencv template matching function MatchTemplatemo within the search range to search for grain features. The nth vertical axis matching grain found in this direction is WYn, and its pixel coordinates are (WYn_X, WYn_Y). Each subsequent slide starts from the lower left corner of the WYn grain, slides a distance of W1_H, and searches for grain features until the condition (WYn_Y - W1_Y) > image height is met, obtaining the pixel coordinates of all the vertical axis matching grains and the number of vertical axis matching grains.

[0143] Step 3: Determine the maximum number of grain columns that can be accommodated based on the number of horizontal axis matching grains, determine the maximum number of grain rows that can be accommodated based on the number of vertical axis matching grains, and determine the initial grain interval and the initial placement angle based on the pixel coordinates of each horizontal axis matching grain and the pixel coordinates of each vertical axis matching grain.

[0144] In the embodiment of the present application, the value obtained by subtracting 1 from the number of horizontal axis matching grains is determined as the maximum number of columns WCol that can be accommodated, and the value obtained by subtracting 1 from the number of vertical axis matching grains is determined as the maximum number of grain rows WRow that can be accommodated.

[0145] Exemplarily, the method for determining the initial grain interval and the initial placement angle can be as follows: Based on the pixel coordinates of each horizontal axis matching grain, obtain the pixel coordinates of the first horizontal axis matching grain and the pixel coordinates of the last horizontal axis matching grain, and based on the pixel coordinates of each vertical axis matching grain, obtain the pixel coordinates of the first vertical axis matching grain and the pixel coordinates of the last vertical axis matching grain; determine the candidate grain interval and the candidate placement angle based on the pixel coordinates of the first horizontal axis matching grain, the pixel coordinates of the last horizontal axis matching grain, the pixel coordinates of the first vertical axis matching grain, and the pixel coordinates of the last vertical axis matching grain; determine the initial grain interval based on the candidate grain interval and the pixel pulse coefficient, and determine the initial placement angle based on the candidate placement angle and the pixel pulse coefficient.

[0146] Optionally, the candidate grain spacing and candidate placement angle are determined according to the following formulas (1)-(4).

[0147] dX_Pix =(WXs_X- WX1_X) / s (1)

[0148] dY_Pix =(WYs_X- WY1_X) / s (2)

[0149] dxY_Pix =(WXs_Y- WX1_Y) / s (3)

[0150] dyX_Pix =(WYs_Y- WY1_Y) / s (4)

[0151] Wherein, dX_Pix and dY_Pix are the candidate grain spacings; dxY_Pix and dyX_Pix are the candidate placement angles; WXs_X and WYs_X are the pixel coordinates of the last horizontally matched grain; WX1_X and WY1_X are the pixel coordinates of the first horizontally matched grain; WXs_Y and WYs_Y are the pixel coordinates of the last vertically matched grain; WX1_Y and WY1_Y are the pixel coordinates of the first vertically matched grain.

[0152] After calculating the candidate grain spacing and candidate placement angle, the initial grain spacing and initial placement angle are determined in combination with the pixel pulse coefficient. Wherein, the pixel pulse coefficient refers to the conversion ratio between the pixel coordinates and the real coordinates.

[0153] dX’ = dX_Pix * XPulesPixRatio (5)

[0154] dY’ = dY_Pix * XPulesPixRatio (6)

[0155] dxY’ = dxY_Pix * YPulesPixRatio (7)

[0156] dyX’ = dyX_Pix * YPulesPixRatio (8)

[0157] Wherein, dX’ and dY’ are the initial grain spacings; dxY’ and dyX’ are the initial placement angles; XPulesPixRatio is the pixel pulse coefficient in the X direction; YPulesPixRatio is the pixel pulse coefficient in the Y direction.

[0158] S302. Determine the expected coordinates of the next grain in the machine tool coordinate system according to the reference coordinates, the maximum number of grains in a row that can be accommodated, the maximum number of grains in a column that can be accommodated, the initial grain spacing, and the initial placement angle.

[0159] Among them, the next grain is the grain determined within the moved field of view by controlling the movement of the machine stage. For example, as Figure 5 shown, the reference grain is A, the next grain is B, ① is the field of view where the reference grain is at the center of the camera scanning field of view, and ② is the field of view where the next grain is at the center of the camera scanning field of view. According to the position of the next grain B, it can be known that the next grain is determined within the moved field of view after controlling the machine stage to move a distance of one field of view. Among them, the grain corresponding to the center of the next field of view is the next grain of the reference grain.

[0160] According to the foregoing content, the next grain is continuously updated, so it is necessary to preset the way of moving the machine stage to determine the new next grain. In the embodiment of the present application, it can be set that the first movement does not exceed one field of view, that is, move a distance of one field of view, and each subsequent movement changes in multiples. For example, the number of fields of view moved n = d * x, where x can be determined according to the size of the crystal disk, and the minimum is 2; d is the number of times the machine stage has moved. If x is 2, then the number of fields of view moved is 2d. Furthermore, the number of fields of view moved for the second time can be determined to be 2 (at this time d is 1), as Figure 6 shown, the new next grain is C. It should be noted that the Figure 5 and Figure 6 are the next grains determined by moving along the X-axis direction, and are on the right side along the X-axis direction, or can also be on the left side along the X-axis direction. The embodiment of the present application does not limit this. In addition, it is also necessary to move along the Y-axis direction to determine the next grain, and its method is the same as the moving direction along the X-axis direction, which will not be elaborated here. Among them, the end condition for X-direction scanning is that the total moving distance of the machine stage in the X direction is greater than the crystal disk diameter WLenth * (2 / 3), that is, Wn_Pos.X - W0_Pox.X > WLenth * (2 / 3). The end condition for Y-direction scanning is that the total moving distance of the machine stage in the Y direction is greater than the crystal disk diameter WLenth * (2 / 3), that is, Wn_Pos.Y - W0_Pox.Y > WLenth * (2 / 3).

[0161] In the embodiment of the present application, the expected coordinates of the next grain are determined according to the reference coordinates of the reference grain, the number of fields of view moved, the maximum number of grains that can be accommodated in a row, the maximum number of grains that can be accommodated in a column, the initial grain interval, and the initial placement angle.

[0162] The determination method of the expected coordinates of the next grain determined in the X direction is shown in the following formulas (8) and (9).

[0163] Wn_Pos_exp.X = W0_ Pos.X + n * WCol * dX’ (8)

[0164] Wn_Pos_exp.Y = W0_Pos.Y + n * WCol * dxY’ (9)

[0165] Wherein, Wn_Pos_exp.X and Wn_Pos_exp.Y are the expected coordinates of the next grain; W0_Pos.X and W0_Pos.Y are the reference coordinates of the reference grain; n * WCol * dX’ and n * WCol * dxY’ are the total moving distances of the machine in the X direction. The determination method of the expected coordinates of the next grain determined in the Y direction is as shown in the following formulas (10) and (11).

[0166] Wn_Pos_exp.X = W0_Pos.X + n * WRow * dyX’ (10)

[0167] Wn_Pos_exp.Y = W0_Pos.Y + n * WRow * dY’ (11)

[0168] Wherein, n * WRow * dyX’ and n * WRow * dY’ are the total moving distances of the machine in the Y direction.

[0169] The method for determining wafer detection parameters provided by the embodiments of the present application first obtains the maximum number of grains in rows and columns that can be accommodated within the effective field of view of the camera, the initial grain spacing, and the initial placement angle, and then determines the expected coordinates of the next grain in the machine coordinate system according to the reference coordinates, the maximum number of grains in rows and columns that can be accommodated, the initial grain spacing, and the initial placement angle. In this method, an optional way to quickly determine the expected coordinates of the next grain is provided; by the maximum number of grains in rows and columns that can be accommodated within the effective field of view of the camera, the initial grain spacing, and the initial placement angle, the total moving distance of the machine is determined, and then the expected coordinates of the next grain are determined according to the sum of the reference coordinates of the reference grain and the total moving distance of the machine, providing a data basis for the subsequent calculation of the grain spacing and the placement angle.

[0170] Based on any of the above embodiments, an embodiment is provided to illustrate the process of calculating the true coordinates of the next grain.

[0171] In an exemplary embodiment, as Figure 7 shown, the next grain is a valid grain; calculating the true coordinates of the next grain in the machine coordinate system includes:

[0172] S401, obtaining the position deviation between the reference grain and the next grain.

[0173] Among them, valid grains refer to grains that can be clearly identified, have a complete form, and meet the calculation requirements. Invalid grains refer to grains that are not suitable for inclusion in the calculation of wafer inspection parameters due to various reasons (such as irregular shape, being blocked, or unable to be clearly identified, etc.).

[0174] In one embodiment, obtaining the position deviation between a reference grain and the next grain includes the following steps:

[0175] Step 1: According to the grain map taken when the next grain is at the center of the camera scanning field of view, search for the matching grain that matches the pre-selected grain feature, and obtain the pixel coordinates of the matching grain.

[0176] The process of obtaining the pixel coordinates of the matching grain in the X direction is as follows: Move the machine stage to the position of the expected coordinates of the next grain (in the X direction) so that the next grain is at the center of the camera scanning field of view. At this time, control the camera to scan the image to obtain the grain map. Call the Opencv template matching function MatchTemplatemo to search for the matching grain W 1 Feature, and obtain the pixel coordinates of the matching grain.

[0177] The process of obtaining the pixel coordinates of the matching grain in the Y direction is as follows: Move the machine stage to the position of the expected coordinates of the next grain (in the Y direction) so that the next grain is at the center of the camera scanning field of view. At this time, control the camera to scan the image to obtain the grain map. Call the Opencv template matching function MatchTemplatemo to search for the matching grain W 1 Feature, and obtain the pixel coordinates of the matching grain.

[0178] Step 2: Determine the pixel deviation coordinates of the matching grain relative to the image center point coordinates according to the pixel coordinates of the matching grain and the image center point coordinates of the grain map.

[0179] Step 3: Convert the pixel deviation coordinates according to the pixel pulse coefficient to obtain the position deviation between the reference grain and the next grain.

[0180] The methods for calculating the position deviation between the reference grain and the next grain in the X direction and the Y direction are the same, and both can use the following formulas (12) and (13).

[0181] XOff =(MatCenter.X – W 1 feature.X)* XPulesPixRatio (12)

[0182] YOff =(MatCenter.Y – W 1feature.Y) * YPulesPixRatio (13)

[0183] Wherein, XOff and YOff are the position deviations between the reference grain and the next grain; MatCenter.X and MatCenter.Y are the coordinates of the center point of the image; W 1 feature.X and W 1 feature.Y are the pixel coordinates of the matching grain; MatCenter.X – W 1 feature.X and MatCenter.Y – W 1 feature.Y are the pixel deviation coordinates of the matching grain relative to the center point of the image.

[0184] S402. Calibrate the expected coordinates of the next grain according to the position deviation between the reference grain and the next grain, and determine the calibrated coordinates as the true coordinates of the next grain.

[0185] In the embodiments of the present application, the methods for calculating the true coordinates of the next grain in the X direction and the Y direction are the same, and both can adopt the following formulas (14) and (15).

[0186] Wn_Pos.X = Wn_Pos_exp.X + XOff (14)

[0187] Wn_Pos.Y = Wn_Pos_exp.Y + YOff (15)

[0188] Wherein, Wn_Pos.X and Wn_Pos.Y are the true coordinates of the next grain.

[0189] The method for determining wafer detection parameters provided by the embodiments of the present application first obtains the position deviation between the reference grain and the next grain, and then calibrates the expected coordinates of the next grain according to the position deviation between the reference grain and the next grain, and determines the calibrated coordinates as the true coordinates of the next grain. In this method, when the next grain is a valid grain, by obtaining the position deviation between the reference grain and the next grain, and then using this position deviation to calibrate the expected coordinates of the next grain, that is, calculating the true coordinates of the next grain, the accuracy of the position of the next grain is improved, thereby improving the accuracy of the grain interval and the placement angle.

[0190] Based on any of the above embodiments, another embodiment is provided to illustrate the process of calculating the true coordinates of the next grain.

[0191] In an exemplary embodiment, such as Figure 8As shown, the next crystal grain is an invalid crystal grain; calculating the true coordinates of the next crystal grain in the machine table coordinate system includes:

[0192] S501, if there is a valid crystal grain in the crystal grain map when the next crystal grain is at the center of the camera scanning field of view, determine the true coordinates of the next crystal grain according to the crystal grain map and the expected coordinates of the next crystal grain.

[0193] In one embodiment, determining the true coordinates of the next crystal grain includes the following steps:

[0194] Step 1, search for valid crystal grains in the crystal grain map that match the pre-selected crystal grain features, and obtain the pixel coordinates of the valid crystal grains.

[0195] In the embodiment of the present application, search for valid crystal grains in the 8-connected domain direction centered on the next crystal grain. The search schematic diagram is as Figure 9 shown. Among them, the black crystal grain is the next crystal grain, and the surrounding gray crystal grains are the valid crystal grains to be searched. Call the Opencv template matching function MatchTemplatemo to search for the valid crystal grain W 2 Feature that matches the crystal grain features, and obtain the pixel coordinates of the valid crystal grains. At the same time, record the number of crystal grain intervals XCount between the valid crystal grains in the X direction and the next crystal grain, and the number of crystal grain intervals YCount between the valid crystal grains in the Y direction and the next crystal grain.

[0196] Step 2, determine the true coordinates of the valid crystal grain in the machine table coordinate system according to the pixel coordinates of the valid crystal grain, the image center coordinates of the crystal grain map, the pixel pulse coefficient, and the expected coordinates of the next crystal grain.

[0197] Exemplarily, the way to determine the true coordinates of the valid crystal grain can be to determine the true deviation coordinates of the valid crystal grain relative to the image center point according to the pixel coordinates of the valid crystal grain, the image center coordinates of the crystal grain map, and the pixel pulse coefficient; determine the true coordinates of the valid crystal grain according to the sum between the true deviation coordinates and the expected coordinates of the next crystal grain. For example, calculate the true coordinates of the valid crystal grain according to the following formulas (16) and (17).

[0198] Wtemp_Pos.X = (MatCenter.X - W 2 Feature.X) * XPulesPixRatio + Wn_Pos_exp.X (16)

[0200] Wtemp_Pos.Y = (MatCenter.Y - W 2 Feature.Y) * YPulesPixRatio + Wn_Pos_exp.Y (17)

[0202] Among them, Wtemp_Pos.X and Wtemp_Pos.Y are the true coordinates of the valid grains; MatCenter.X and MatCenter.Y are the coordinates of the center point of the image; W 2 Feature.X and W 2 Feature.Y are the pixel coordinates of the valid grains; (MatCenter.X - W 2 Feature.X)*XPulesPixRatio and (MatCenter.Y - W 2 Feature.Y)*YPulesPixRatio are the true deviation coordinates of the valid grains relative to the center point of the image.

[0203] Step 3, determine the true coordinates of the next grain according to the true coordinates of the valid grains, the number of grains between the valid grain and the next grain, the initial grain interval, and the initial placement angle.

[0204] Exemplarily, the way to determine the true coordinates of the next grain can be to determine the true distance between the valid grain and the next grain according to the number of grain intervals between the valid grain and the next grain, the initial grain interval, and the initial placement angle; determine the true coordinates of the next grain according to the difference between the true coordinates of the valid grain and the true distance. For example, calculate the true coordinates of the next grain according to the following formulas (18) and (19).

[0205] Wn_Pos.X = Wtemp_Pos.X - (XCount * dX’ + YCount * dyX’) (18)

[0206] Wn_Pos.Y = Wtemp_Pos.Y - (XCount * dxY’ + YCount * dY’) (19)

[0207] Among them, XCount * dX’ + YCount * dyX’ and XCount * dxY’ + YCount * dY’ are the true distances between the valid grain and the next grain.

[0208] S502, if there is no valid grain in the grain map, control the machine platform to move to re - obtain the grain map, and determine the true coordinates of the next grain according to the re - obtained grain map and the expected coordinates of the next grain.

[0209] Exemplarily, the way to control the machine platform to move to re - obtain the grain map can be in the eight - connected domain direction centered on the current field of view. After moving the machine platform by the distance of the number of grains of one field of view size, control the camera to scan the image to obtain the re - obtained grain map.

[0210] When there is no valid grain in the current field of view, move a grain distance equal to the size of one field of view in the direction of the eight-connected domain centered on the current field of view. The machine coordinates of the center of the moved field of view are CameTempPos. CameTempPos.X = Wn_Pos_exp.X + dX' * WCol; CameTempPos.Y = Wn_Pos_exp.Y + dY' * WRow. The mapping relationship between the grains in the moved field of view and the grains in the original field of view, that is, the pixel coordinates where they are located are exactly the same. At this time, control the camera to scan the image to obtain the newly acquired grain map.

[0211] In one embodiment, determining the true coordinates of the next grain according to the newly acquired grain map and the expected coordinates of the next grain includes the following steps:

[0212] Step 1, search for valid grains that match the pre-selected grain features in the newly acquired grain map, and obtain the pixel coordinates of the valid grains.

[0213] Call the Opencv template matching function MatchTemplatemo to search for valid grains that match the grain features in the newly acquired grain map, and obtain the pixel coordinates of the valid grains. This step is the same as Step 1 of the above S501 and will not be elaborated here.

[0214] Step 2, determine the true coordinates of the valid grains in the machine coordinate system according to the pixel coordinates of the valid grains, the image center coordinates of the grain map, the pixel pulse coefficient, and the expected coordinates of the next grain.

[0215] Exemplarily, determine the true deviation coordinates of the valid grains relative to the image center point according to the pixel coordinates of the valid grains, the image center coordinates of the grain map, and the pixel pulse coefficient; determine the true coordinates of the valid grains according to the sum between the true deviation coordinates and the expected coordinates of the next grain. Specifically, refer to the above formulas (16) and (17).

[0216] Step 3, determine the true coordinates of the next grain according to the true coordinates of the valid grains, the initial grain interval, the maximum number of grains that can be accommodated in the row and the maximum number of grains that can be accommodated in the column within the effective field of view of the camera.

[0217] Exemplarily, determine the true coordinates of the mapped grains in the machine coordinate system according to the true coordinates of the valid grains, the number of grain intervals between the valid grains and the next grain, the initial grain interval, and the initial placement angle; the mapped grains are the grains in the newly acquired grain map that have the same pixel coordinates as the next grain in the original field of view; determine the moving distance of the machine according to the initial grain interval, the maximum number of grains that can be accommodated in the row and the maximum number of grains that can be accommodated in the column; determine the true coordinates of the next grain according to the difference between the true coordinates of the mapped grains and the moving distance.

[0218] Wn_map_Pos.X = Wtemp_Pos.X - (XCount * dX’ + YCount * dyX’) (20)

[0219] Wn_map_Pos.Y = Wtemp_Pos.Y - (XCount * dxY’ + YCount * dY’) (21)

[0220] Wn_Pos.X = Wn_map_Pos.X - dX’ * WCol (22)

[0221] Wn_Pos.Y = Wn_map_Pos.Y - dY’ * WRow (23)

[0222] Wherein, Wn_map_Pos.X and Wn_map_Pos.Y are the true coordinates of the mapped die; dX’ * WCol and dY’ * WRow are the moving distances of the machine

[0223] For the method for determining wafer detection parameters provided in the embodiments of the present application, if there is a valid die in the die map when the next die is at the center of the camera scanning field of view, the true coordinates of the next die are determined according to the die map and the expected coordinates of the next die; if there is no valid die in the die map, the machine is controlled to move to re-acquire the die map, and the true coordinates of the next die are determined according to the re-acquired die map and the expected coordinates of the next die. In this method, when the next die is an invalid die, the exact position of the next die is deduced through the valid dies around the invalid die. Equivalently, in the calculation process of the placement angle of the die interval, the influence of the defective die on the algorithm is considered, and the influence of the defective die is reduced by reverse derivation through the surrounding valid points, improving the robustness of the algorithm.

[0224] Based on the above embodiments, an embodiment is provided to illustrate the process of updating the die interval and placement angle.

[0225] In an exemplary embodiment, as Figure 10 shown, updating the die interval and placement angle of the wafer to be detected according to the true coordinates includes:

[0226] S601, obtaining the true coordinates of the penultimate die in the machine coordinates; the penultimate die is the adjacent next die before the next die.

[0227] Continue to refer to Figure 6, if the current next grain is Grain B, then the previous next grain is Grain A. After each movement of the machine, the true coordinates of the next grain are calculated, and the true coordinates of the next grain calculated after the previous movement can be directly obtained, which are the true coordinates of the previous next grain.

[0228] S602. Determine the number of grain intervals between the previous next grain and the next grain according to the maximum number of grains in a row and the maximum number of grains in a column that can be accommodated within the effective field of view of the camera, and the number of field of view intervals between the previous next grain and the next grain.

[0229] In the embodiments of the present application, the number of grain intervals between the previous next grain and the next grain in the X direction is the product of the number of moving fields of view and the maximum number of columns, that is, n * WCol. The number of grain intervals between the previous next grain and the next grain in the Y direction is the product of the number of moving fields of view and the maximum number of rows, that is, n * WRow.

[0230] S603. Determine the true distance between the previous next grain and the next grain according to the true coordinates of the previous next grain and the true coordinates of the next grain.

[0231] In the embodiments of the present application, the true distance between the previous next grain and the next grain in the X direction is the difference between the true coordinate value of the next grain in the X direction and the true coordinate value of the previous next grain in the X direction, that is, Wn_Pos.X - Wn-1_Pos.X. The true distance between the previous next grain and the next grain in the Y direction is the difference between the true coordinate value of the next grain in the Y direction and the true coordinate value of the previous next grain in the Y direction, that is, Wn_Pos.Y - Wn-1_Pos.Y.

[0232] S604. Update the grain interval and the placement angle according to the number of grain intervals and the true distance.

[0233] The true distance includes the true distance Wn_Pos.X - Wn-1_Pos.X in the horizontal axis direction and the true distance Wn_Pos.Y - Wn-1_Pos.Y in the vertical axis direction; the number of grain intervals includes the number of grain intervals n * WCol in the horizontal axis direction and the number of grain intervals n * WRow in the vertical axis direction.

[0234] Exemplarily, the way to update the grain interval according to the number of grain intervals and the true distance can be to determine the grain interval in the horizontal axis direction according to the ratio between the true distance in the horizontal axis direction and the number of grain intervals in the horizontal axis direction; determine the grain interval in the vertical axis direction according to the ratio between the true distance in the vertical axis direction and the number of grain intervals in the vertical axis direction; and determine the grain intervals in the horizontal axis direction and the vertical axis direction as the updated grain intervals. For example, calculate the updated grain intervals according to the following formulas (24) and (25).

[0235] dX = (Wn_Pos.X - Wn-1_Pos.X) / n * WCol (24)

[0236] dY = (Wn_Pos.Y - Wn-1_Pos.Y) / n * WRow (25)

[0237] Wherein, dX is the grain interval in the horizontal axis direction; dY is the grain interval in the vertical axis direction.

[0238] Exemplarily, according to the number of grain intervals and the true distance coordinates, the way to update the placement angle can be to determine the offset distance in the horizontal axis direction according to the ratio between the true distance in the horizontal axis direction and the number of grain intervals in the vertical axis direction; determine the offset distance in the vertical axis direction according to the ratio between the true distance in the vertical axis direction and the number of grain intervals in the horizontal axis direction; determine the offset distances in the horizontal axis direction and the vertical axis direction as the updated placement angle. For example, calculate the updated placement angle according to the following formulas (26) and (27).

[0239] dxY = (Wn_Pos.Y - Wn-1_Pos.Y) / n * WCol (26)

[0240] dyX = (Wn_Pos.X - Wn-1_Pos.X) / n * WRow (27)

[0241] Wherein, dxY is the offset distance in the vertical axis direction; dyX is the offset distance in the horizontal axis direction.

[0242] The method for determining wafer detection parameters provided by the embodiments of the present application first obtains the true coordinates of the previous-next grain in the machine coordinates; the previous-next grain is the adjacent next grain before the next grain, and then determines the number of grain intervals between the previous-next grain and the next grain according to the maximum number of grain rows and the maximum number of grain columns that can be accommodated within the effective field of view of the camera, and the number of field-of-view intervals between the previous-next grain and the next grain. After that, according to the true coordinates of the previous-next grain and the true coordinates of the next grain, the true distance between the previous-next grain and the next grain is determined. Finally, according to the number of grain intervals and the true distance, the grain interval and the placement angle are updated. In this method, by calculating the number of grain intervals between the previous grain and the next grain, and the true distance between the previous-next grain and the next grain, the grain interval and the placement angle can be quickly calculated based on the number of grain intervals and the true distance, and the true distance between the previous-next grain and the next grain is calculated based on the true coordinates of the next grain, which improves the accuracy of the true distance calculation, and thus improves the update accuracy of the grain interval and the placement angle.

[0243] Based on the above embodiments, an embodiment for the process of obtaining the reference coordinates of the reference grains is provided for description.

[0244] In an exemplary embodiment, as Figure 11 shown, the method further includes:

[0245] S701, according to the coordinates of the taught feature points in the machine table coordinate system, control the feature points in the wafer to be detected to be at the center of the camera scanning field of view; the taught feature points are reference points for positioning the wafer to be detected.

[0246] In the embodiments of the present application, before calculating the grain interval and the placement angle, another wafer is fixed on the machine table, and the machine table is controlled to move into the camera field of view until the taught feature point Make appears, and the Make feature is framed for wafer disk positioning. Among them, Make is required to be the only feature point in the camera field of view. For example, Make is the only special shape in the wafer. Record the platform position MakeCame unit pulse Pules, and this position will be used as the starting position when positioning Make. Among them, MakeCame is the coordinate of the taught feature point in the machine table coordinate system.

[0247] Move the camera to be controlled to the MakeCame position, make the feature points in the wafer to be detected be at the center of the camera scanning field of view, and control the camera to scan the image to obtain the currently scanned grain map. Among them, the feature points in the wafer to be detected are similar or the same as the taught feature points. For example, it is the only special shape in the wafer to be detected.

[0248] S702, determine the true coordinates of the feature points in the wafer to be detected in the machine table coordinate system according to the currently scanned grain map.

[0249] In one embodiment, the steps of determining the true coordinates of the feature points include:

[0250] Step 1, search for matching feature points that match the taught feature points in the grain map, and obtain the pixel coordinates of the matching feature points.

[0251] The platform moves to the MakeCame position to obtain the grain map. At this time, there is a mapping relationship between the image center MatCenter and MakeCame. Call the Opencv template matching function MatchTemplatemo to search for matching feature points that match the taught feature points, and obtain the pixel coordinates MakeFeature of the matching feature points.

[0252] Step 2, according to the pixel coordinates of the matching feature points, the image center point coordinates of the grain map, and the pixel pulse coefficient, determine the true deviation coordinates of the matching feature points relative to the image center point.

[0253] Step 3: Determine the true coordinates of the feature points based on the sum between the true deviation coordinates and the coordinates of the taught feature points.

[0254] Calculate the true coordinates of the feature points in the wafer to be detected according to the following formulas (28) and (29).

[0255] MakePos.X = (MatCenter.X - MakeFeature.X) * XPulesPixRatio + MakeCame.X (28)

[0256] MakePos.Y = (MatCenter.Y - MakeFeature.Y) * YPulesPixRatio + MakeCame.Y (29)

[0257] Where MakePos.X and MakePos.Y are the true coordinates of the feature points; MakeFeature.X and MakeFeature.Y are the pixel coordinates of the matched feature points; MakeCame.X and MakeCame.Y are the coordinates of the taught feature points; (MatCenter.X - MakeFeature.X) * XPulesPixRatio and (MatCenter.Y - MakeFeature.Y) * YPulesPixRatio are the true deviation coordinates of the matched feature points relative to the center point of the image.

[0258] S703: Determine the reference coordinates of the reference die according to the true coordinates of the feature points in the wafer to be detected.

[0259] In one embodiment, determining the reference coordinates of the reference die according to the true coordinates of the feature points in the wafer to be detected includes the following steps:

[0260] Step 1: Control the feature points to be at the center of the camera scanning field of view according to the true coordinates of the feature points, and control the camera to scan the image to obtain a die map.

[0261] In the embodiments of the present application, the control machine is moved to the position of the true coordinates of the feature points, so that the true coordinates of the feature points are at the center of the camera scanning field of view. At this time, the camera is controlled to scan the image to obtain a die map.

[0262] Step 2: If the die map includes valid dies, determine the reference coordinates of the reference die according to the die map and the true coordinates of the feature points.

[0263] Exemplarily, the method for determining the reference coordinates of the reference grain according to the grain map and the true coordinates of the feature points may be to search for a matching grain in the grain map that matches the pre-selected grain feature, and obtain the pixel coordinates of the matching grain; according to the pixel coordinates of the matching grain, the image center coordinates of the grain map, and the pixel pulse coefficient, determine the true deviation coordinates of the matching grain relative to the image center point; determine the reference coordinates of the reference grain according to the sum between the true deviation coordinates and the true coordinates of the feature points.

[0264] Call the Opencv template matching function MatchTemplatemo to search for a matching grain W in the grain map that matches the pre-selected grain feature. 3 Feature, and obtain the pixel coordinates of the matching grain. Further, determine the reference coordinates of the reference grain based on the following formulas (30) and (31).

[0265] W0_Pos.X = (MatCenter.X - W 3 Feature.X) * XPulesPixRatio + MakePos.X (30)

[0266] W0_Pos.Y = (MatCenter.Y - W 3 Feature.Y) * YPulesPixRatio + MakePos.Y (31)

[0267] Among them, W0_Pos.X and W0_Pos.Y are the reference coordinates of the reference grain; W 3 Feature.X and W 3 Feature.Y are the pixel coordinates of the matching grain; (MatCenter.X - W 3 Feature.X) * XPulesPixRatio and (MatCenter.Y - W 3 Feature.Y) * YPulesPixRatio are the true deviation coordinates of the matching grain relative to the image center point.

[0268] Step 3, if the grain map does not include valid grains, control the machine stage to move to re-acquire the grain map, and determine the reference coordinates of the reference grain according to the re-acquired grain map.

[0269] Exemplarily, the method for controlling the machine stage to move to re-acquire the grain map may be to control the machine stage to move in the horizontal axis direction of the feature point, and when the machine stage moves to a preset distance from the true coordinates of the feature point, control the camera to scan the image to obtain the re-acquired grain map; the preset distance is the distance of a preset number of field widths.

[0270] When there are no valid grains in the grain map, the machine stage needs to be moved to search for reference grains outside the shooting field of MakePos. The moving methods include, for example, moving in a certain direction or moving around MakePos as the center. In the embodiment of the present application, after moving N view widths ViewW in the X direction, the camera is controlled to scan the image to obtain a newly acquired grain map.

[0271] Exemplarily, determining the reference coordinates of the reference grain according to the newly acquired grain map includes the following steps:

[0272] Step (1), determining the true coordinates of the center of the field of view of the newly acquired grain map in the machine stage coordinate system according to the sum of the true coordinates of the feature points and the preset distance.

[0273] CamePosN.X = MakePos.X + N * ViewW (32)

[0274] CamePosN.Y = MakePos.Y + N * ViewH (33)

[0275] Wherein, CamePosN.X and CamePosN.Y are the true coordinates of the center of the field of view of the newly acquired grain map; ViewW is the view width; ViewH is the view height.

[0276] Step (2), searching for matching grains that match the pre-selected grain features in the newly acquired grain map, and obtaining the pixel coordinates of the matching grains.

[0277] Call the Opencv template matching function MatchTemplatemo to search for matching grains W that match the pre-selected grain features in the newly acquired grain map 4 Feature, and obtain the pixel coordinates of the matching grains.

[0278] Step (3), determining the true deviation coordinates of the matching grain relative to the image center point according to the pixel coordinates of the matching grain, the image center point coordinates of the newly acquired grain map, and the pixel pulse coefficient.

[0279] Step (4), determining the reference coordinates of the reference grain according to the sum of the true deviation coordinates and the true coordinates of the center of the field of view.

[0280] W0_Pos.X = (MatCenter.X - W 4 Feature.X) * XPulesPixRatio + CamePosN.X (34)

[0281] W0_Pos.Y = (MatCenter.Y - W 4Feature.Y) * YPulesPixRatio + CamePosN.Y (35)

[0282] The method for determining wafer detection parameters provided by the embodiments of the present application first controls the feature points in the wafer to be detected to be at the center of the camera scanning field of view according to the coordinates of the taught feature points in the machine tool coordinate system. The taught feature points are reference points for positioning the wafer to be detected. Then, according to the actual coordinates of the feature points in the wafer to be detected in the machine tool coordinate system determined from the currently scanned die map, the reference coordinates of the reference die are determined. In this method, by teaching one feature point, and then finding the valid dies around the feature point based on the taught feature point, selecting one valid die as the reference die, and calculating the reference coordinates of the reference die based on the coordinates of the taught feature point, it provides data support for the calculation of wafer detection parameters. And in the embodiments of the present application, only one feature point needs to be taught to run the algorithm to calculate the die pitch and placement angle, which simplifies the modeling steps, reduces the probability of operation errors, and further improves the calculation accuracy of wafer detection parameters.

[0283] In addition, in one embodiment, the complete process of calculating wafer detection parameters is described.

[0284] In wafer detection, a modeling process is required to select die features and establish a detection template process. In the modeling process of the embodiments of the present application, while selecting the feature dies, the initial pitch between dies and the initial inclination of the die disk are calculated, which are used as the basic data for subsequent algorithms.

[0285] Among them, the pulse pitch in the X direction of the die is represented by dX, and the Y direction pulse offset caused by the inclination of the die disk for every dX distance is represented by dxY. The pulse pitch in the Y direction of the die is represented by dY, and the X direction pulse offset caused by the inclination of the die disk for every dY distance is represented by dyX. The die feature is the only feature for the algorithm to identify the die.

[0286] (1) Specific implementation one: Die scanning algorithm within the effective field of view

[0287] (2) Take N * N pictures according to the S-shaped movement trajectory, and use image stitching technology to synthesize a template picture for algorithm input. The movement trajectory requires that for each picture taken at each movement distance, there must be an overlapping area between adjacent pictures to meet the requirement that the template picture is larger than the camera field of view.

[0288] (3) Based on the template image, an algorithm template is established on the template image. First, select the size range of the grains. The grains within the range should ensure clear features and be free from the influence of dirt. There should be no other grain features within the selected range. Here, the selected grain range is called a grain. Secondly, select the grain feature, which serves as the unique feature of the grain and is an important basis for the algorithm to identify the grain. And the grain feature is usually included within the grain size. Taking this grain as the starting grain W1, the position of this grain in the image coordinate system is (W1_X, W1_Y).

[0289] (4) Taking the upper right corner of the W1 grain as the starting point for grain search. Slide a distance equal to the width of one grain W1_W along the X direction, and call the Opencv template matching function MatchTemplatemo to search for grain features within the search range. The nth grain found in this direction is WXn, and its coordinate position is (WXn_X, WXn_Y), and update dX_Pix and dxY_Pix. For each subsequent slide, take the upper right corner of the WXn grain as the starting point, slide a distance of W1_W, and search for grain features, updating dX_Pix and dxY_Pix until the condition (WXn_X - W1_X) > the width of the image is met. At this point, n - 1 is the maximum number of columns, WCol, that the grains can accommodate within one field of view.

[0290] (5) Taking the lower left corner of the W1 grain as the starting point for grain search. Slide a distance equal to the height of one grain W1_H along the Y direction, and call the Opencv template matching function MatchTemplatemo to search for grain features within the search range. The nth grain found in this direction is WYn, and its coordinate position is (WYn_X, WYn_Y), and update dY_Pix and dyX_Pix. For each subsequent slide, take the LeftDown of the WYn grain as the starting point, slide a distance of W1_H, search for grain features, and update dY_Pix and dyX_Pix until the condition (WYn_Y - W1_Y) > the height of the image is met. At this point, n - 1 is the maximum number of rows, WRow, that the grains can accommodate within one field of view.

[0291] (6) Specific implementation two: Grain scanning based on the crystal disk

[0292] Input data required for Implementation 2 calculated by the "grain scanning algorithm within the effective field of view" in (1): The field of view includes the grain column WCol, the grain row WRow in the field of view, the grain width W1_W, the grain height W1_H, the grain pixel pitch dX_Pix, the grain pixel pitch dY_Pix, the y-direction offset dxY_Pix (pixel offset) caused by the tilt of the tray for each dx, and the x-direction offset dyX_Pix (pixel offset) caused by the tilt of the tray for each dy. In addition, it is also necessary to calculate the ratio between pixels and pulses through measurement means, which is XPulesPixRatio in the X direction and YPulesPixRatio in the Y direction.

[0293] (7) Perform Make point teaching. The machine moves until Make appears within the camera's field of view, and then select the Make feature by drawing a box for crystal disk positioning. Make is required to be the only feature point in the camera's field of view. Record the platform position MakeCame in unit pulses Pules, and this position will be used as the starting position for Make positioning.

[0294] (8) The machine moves to the MakeCame position to obtain an image. At this time, there is a mapping relationship between the image center MatCenter and MakeCame. Call the Opencv template matching function MatchTemplatemo to search for the pixel coordinates MakeFeature of the Make feature, calculate the pulse distance between Make and the image center, and then calculate the machine coordinates MakePos corresponding to Make.

[0295] (9) Search for the starting grain of the algorithm with MakePos as the center. To improve robustness, consider two cases. Take pictures at the MakePos position, where the pictures contain valid grains and the pictures contain invalid grains.

[0296] (10) If the picture contains valid grains, the Opencv template matching function MatchTemplatemo can be called to search for the grain feature WFeature and calculate the machine coordinates W0_Pos corresponding to the valid grain (reference grain).

[0297] (11) If the picture does not contain valid grains, the platform needs to be moved to search for grains outside the field of view at the MakePos position. The moving methods include, for example, moving in a certain direction or moving with MakePos as the center. Only one of the methods is implemented below. Move a distance of N field widths ViewW in the X direction, and the machine coordinates corresponding to the center of the field of view should be CamePosN. Each time it moves, it will search for valid grains in the field of view until valid grains are found and then stop searching. The machine coordinates W0_Pos corresponding to the valid grain (reference grain).

[0298] (12) Starting from the effective grain, calculate the position of the next grain. The calculation direction of the next grain position should be the four-connected domain direction centered on the effective grain, as shown in Figure 12a (The black part is the field of view where the reference grain is located, and the gray part is the field of view where the next grain is located). Take any direction as the starting scanning direction, but note that the scanning direction must ensure sufficient movement distance. After the starting direction scanning is completed, continue to scan the vertical direction of the four-connected domain, and the position of the grains scanned historically can be used as the starting point of the next scanning direction. As shown in Figure 12b . This implementation only demonstrates one of them. Determine the initial scanning direction X, then scan the Y direction, and calculate the initial grain interval and the initial wafer tilt degree (initial placement angle).

[0299] (13) Calculate the expected position Wn_Pos_exp of the next grain, where n is the number of fields of view. The first movement should ensure that the movement does not exceed one field of view after the movement, that is, n is 1. The machine moves to the position Wn_Pox_exp, takes an image, calls the Opencv template matching function MatchTemplatemo to search for the grain feature WFeature, calculates the deviation XOff, YOff between the real position and the expected position of the next grain, and then calculates the real position Wn_Pos of the next grain, and updates the pulse pitch of the grain and the wafer tilt degree.

[0300] (14) Loop and execute (13). After each loop, the number of fields of view moved will show a multiple change. For example, n = n * x. x can be determined according to the size of the crystal disc, and the minimum is 2. The end condition for scanning in the X direction is that the movement distance is greater than the crystal disc diameter WLenth * (2 / 3).

[0301] (15) Calculate the expected position Wn_Pos_exp of the next grain, where n is the number of fields of view. The first movement should ensure that the movement does not exceed one field of view after the movement, that is, n is 1. The camera moves to the position Wn_Pox_exp, takes an image, calls the Opencv template matching function MatchTemplatemo to search for the grain feature WFeature, calculates the deviation XOff, YOff between the real position and the expected position of the next grain, and the real position Wn_Pos. And update the pulse pitch of the grain.

[0302] (16) Loop and execute (15). After each loop, the number of fields of view moved will show a multiple change. For example: n = n * x. x can be determined according to the size of the crystal disc, and the minimum is 2. The end condition for scanning in the Y direction is that the movement distance is greater than the crystal disc diameter WLenth * (2 / 3).

[0303] (17) During the scanning process, there may be bad points when moving to the desired position of the crystal grain. At this time, it is necessary to use other surrounding crystal grains to reverse-deduce the true position of the desired crystal grain. Two situations will occur here: there are other valid crystal grains within the field of view, and there are no valid crystal grains within the field of view.

[0304] (18) When there are valid crystal grains within the field of view, search for valid crystal grains in the 8-connected domain direction with the bad-point crystal grain as the center. Call the Opencv template matching function MatchTemplatemo to search for the crystal grain feature WFeature, and calculate and record the number of searches in the x direction XCount and the number of searches in the y direction YCount. First, calculate the machine coordinates corresponding to WFeature, and then reverse-deduce the bad point Wn_Pos.

[0305] (19) When there are no valid crystal grains within the field of view, move a distance equal to the size of one field of view in the 8-connected domain direction with the current field of view as the center. The machine coordinates after movement are CameTempPos. The crystal grains within the moved field of view and the crystal grains within the original field of view are in a mutual mapping relationship, that is, their pixel coordinates are exactly the same. Refer to step (18) to calculate the true coordinates Wn_map_Pox of the mapped position of the bad point within the moved field of view, and then deduce the true coordinates of the bad point.

[0306] (20) Steps 1 to 19 are used to obtain the crystal grain spacing dX, dY, and the tilting degree of the wafer tray dxY, dYx. The true machine coordinates corresponding to all crystal grains can be calculated through the data.

[0307] In this embodiment, the teaching is simplified; only one make point needs to be taught. Starting from a certain crystal grain around the make point, calculate the crystal grain interval and the angle of the crystal disk through an L-shaped movement trajectory. Improve the accuracy; a. Combine shooting and movement, and use the method of calculating while verifying, repeating the three steps of calculation, verification, and correction. b. According to the initial crystal grain spacing obtained during modeling, calculate the true distance between the specified number of crystal grains, move to the specified position, and then use the camera to verify and correct, and update the crystal grain spacing. c. Repeat step b, and the number of crystal grains participating in the calculation each time is a multiple of the previous time. The more crystal grains participate in the calculation, the higher the accuracy. Improve the robustness; during the execution of the algorithm, the existence of bad points will directly affect the effect of the algorithm. Considering the influence of bad-point crystal grains on the algorithm, there are the following two solutions for bad-point situations: 1) Calculate the exact position where the bad point originally was through the positions of surrounding good-point crystal grains. 2) Avoid the influence of bad points by changing the number of particles participating in the calculation. Improve the robustness, overcome the influence of bad points on the algorithm, and reduce the influence of bad points through the reverse deduction of surrounding valid points. Simplify the modeling steps, and the algorithm can be run only by setting one anchor point, reducing the operation difficulty of employees. Improve the accuracy, and the scanning method of running while correcting prevents error accumulation, and gradually increases the scanning length to improve the calculation accuracy.

[0308] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are sequentially shown according to the indications of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0309] Based on the same inventive concept, an embodiment of the present application also provides a wafer detection parameter determination device for implementing the wafer detection parameter determination method involved above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the wafer detection parameter determination device provided below can refer to the limitations on the wafer detection parameter determination method in the above text, and will not be repeated here.

[0310] In an exemplary embodiment, as Figure 13 shown, a wafer detection parameter determination device 1 is provided, including: an expected coordinate determination module 10, a parameter update module 20, and a parameter determination module 30, where:

[0311] The expected coordinate determination module 10 is configured to, when the reference die in the wafer to be detected is fixed on the machine stage and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine stage, determine the expected coordinate of the next die in the machine stage coordinate system according to the reference coordinate of the reference die in the machine stage coordinate system;

[0312] The parameter update module 20 is configured to control the next die to be at the center of the camera scanning field of view according to the expected coordinate, calculate the actual coordinate of the next die in the machine stage coordinate system, and update the die interval and placement angle of the wafer to be detected according to the actual coordinate;

[0313] The parameter determination module 30 is configured to recalculate the expected coordinate of the new next die according to the reference coordinate and the total movement distance of the machine stage, and loop to execute the process of updating the die interval and placement angle of the wafer to be detected until the total movement distance of the machine stage meets the preset condition, and determine the actual die interval and actual placement angle of the wafer to be detected as the die interval and placement angle obtained in the last update.

[0314] In one of the embodiments, the above-mentioned expected coordinate determination module 10 is further configured to:

[0315] Obtain the maximum number of grains in a row and the maximum number of grains in a column that can be accommodated within the effective field of view of the camera, the initial grain spacing, and the initial placement angle; based on the reference coordinates, the maximum number of grains in a row, the maximum number of grains in a column, the initial grain spacing, and the initial placement angle, determine the expected coordinates of the next grain in the machine tool coordinate system.

[0316] In one embodiment, the above-mentioned expected coordinate determination module 10 is further configured to:

[0317] Obtain the starting point grain in the wafer template map of the wafer to be detected; the wafer template map is obtained by splicing a plurality of grain maps scanned according to a preset scanning trajectory; using the upper right corner of the starting point grain as the starting point for grain search, slide a distance equal to the width of one grain along the horizontal axis direction, search for the horizontally matching grains that match the pre-selected grain features until the preset horizontal search stop condition is met, and obtain the number of horizontally matching grains and the pixel coordinates of each horizontally matching grain; and, using the lower left corner of the starting point grain as the starting point for grain search, slide a distance equal to the height of one grain along the vertical axis direction, search for the vertically matching grains that match the grain features until the preset vertical search stop condition is met, and obtain the number of vertically matching grains and the pixel coordinates of each vertically matching grain.

[0318] Determine the maximum number of grains in a column according to the number of horizontally matching grains, determine the maximum number of grains in a row according to the number of vertically matching grains, and determine the initial grain spacing and the initial placement angle according to the pixel coordinates of each horizontally matching grain and the pixel coordinates of each vertically matching grain.

[0319] In one embodiment, the above-mentioned parameter update module 20 is further configured to:

[0320] Obtain the position deviation between the reference grain and the next grain; according to the position deviation between the reference grain and the next grain, calibrate the expected coordinates of the next grain, and determine the calibrated coordinates as the true coordinates of the next grain.

[0321] In one embodiment, the above-mentioned parameter update module 20 is further configured to:

[0322] According to the grain map taken when the next grain is at the center of the camera scanning field of view, search for the matching grains that match the pre-selected grain features, and obtain the pixel coordinates of the matching grains; according to the pixel coordinates of the matching grains and the image center point coordinates of the grain map, determine the pixel deviation coordinates of the matching grains relative to the image center point; convert the pixel deviation coordinates according to the pixel pulse coefficient to obtain the position deviation between the reference grain and the next grain.

[0323] In one embodiment, the above-mentioned parameter update module 20 is further configured to:

[0324] If there is a valid grain in the grain map when the next grain is at the center of the camera scanning field of view, determine the true coordinates of the next grain according to the grain map and the expected coordinates of the next grain; if there is no valid grain in the grain map, control the machine stage to move to re-acquire the grain map, and determine the true coordinates of the next grain according to the re-acquired grain map and the expected coordinates of the next grain.

[0325] In one embodiment, the above parameter update module 20 is further configured to:

[0326] In the eight-connected domain direction centered on the current field of view, move the machine stage by a number of grain distances equal to the size of one field of view, and then control the camera to scan the image to obtain the re-acquired grain map.

[0327] In one embodiment, the above parameter update module 20 is further configured to:

[0328] Search for valid grains that match the pre-selected grain features in the re-acquired grain map, and obtain the pixel coordinates of the valid grains; determine the true coordinates of the valid grains in the machine stage coordinate system according to the pixel coordinates of the valid grains, the image center coordinates of the grain map, the pixel pulse coefficient, and the expected coordinates of the next grain; determine the true coordinates of the next grain according to the true coordinates of the valid grains, the initial grain interval, the maximum number of grains that can be accommodated in a row within the effective field of view of the camera, and the maximum number of grains that can be accommodated in a column.

[0329] In one embodiment, the above parameter update module 20 is further configured to:

[0330] Determine the true coordinates of the mapped grain in the machine stage coordinate system according to the true coordinates of the valid grain, the number of grain intervals between the valid grain and the next grain, the initial grain interval, and the initial placement angle; the mapped grain is the grain in the re-acquired grain map that has the same pixel coordinates as the next grain in the original field of view; determine the moving distance of the machine stage according to the initial grain interval, the maximum number of grains that can be accommodated in a row, and the maximum number of grains that can be accommodated in a column; determine the true coordinates of the next grain according to the difference between the true coordinates of the mapped grain and the moving distance.

[0331] In one embodiment, the above parameter update module 20 is further configured to:

[0332] Obtain the true coordinates of the previous next die in the machine coordinates; the previous next die is the adjacent next die before the next die; determine the die interval number between the previous next die and the next die according to the maximum number of die rows and the maximum number of die columns that can be accommodated within the effective field of view of the camera, and the number of field of view intervals between the previous next die and the next die; determine the true distance between the previous next die and the next die according to the true coordinates of the previous next die and the true coordinates of the next die; update the die interval and the placement angle according to the die interval number and the true distance.

[0333] Each module in the above wafer detection parameter determination device can be implemented in whole or in part by software, hardware, and their combination. Each of the above modules can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form so that the processor can call and execute the operations corresponding to each of the above modules.

[0334] In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the following steps are implemented:

[0335] When the reference die in the wafer to be detected is fixed on the machine and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine, determine the expected coordinates of the next die in the machine coordinate system according to the reference coordinates of the reference die in the machine coordinate system;

[0336] Control the next die to be at the center of the camera scanning field of view according to the expected coordinates, calculate the true coordinates of the next die in the machine coordinate system, and update the die interval and the placement angle of the wafer to be detected according to the true coordinates;

[0337] Recalculate the expected coordinates of the new next die according to the reference coordinates and the total moving distance of the machine, and loop to execute the process of updating the die interval and the placement angle of the wafer to be detected until the total moving distance of the machine meets the preset condition, and determine the true die interval and the true placement angle of the wafer to be detected as the die interval and the placement angle obtained in the last update.

[0338] The implementation principles and technical effects of the steps implemented by the processor in the embodiments of the present application are similar to the principles of the above wafer detection parameter determination method, and will not be elaborated here.

[0339] In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0340] When the reference die in the wafer to be detected is fixed on the machine stage and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine stage, determine the expected coordinates of the next die in the machine stage coordinate system according to the reference coordinates of the reference die in the machine stage coordinate system;

[0341] Control the next die to be at the center of the camera scanning field of view according to the expected coordinates, calculate the actual coordinates of the next die in the machine stage coordinate system, and update the die interval and placement angle of the wafer to be detected according to the actual coordinates;

[0342] Recalculate the expected coordinates of the new next die according to the reference coordinates and the total moving distance of the machine stage, and loop through the process of updating the die interval and placement angle of the wafer to be detected until the total moving distance of the machine stage meets the preset conditions, and determine the die interval and placement angle obtained from the last update as the actual die interval and actual placement angle of the wafer to be detected.

[0343] The implementation principles and technical effects of the steps implemented when the computer program in the embodiments of the present application is executed by the processor are similar to the principles of the above wafer detection parameter determination method, and will not be elaborated here.

[0344] In one embodiment, a computer program product is provided, including a computer program, which when executed by a processor implements the following steps:

[0345] When the reference die in the wafer to be detected is fixed on the machine stage and the reference die in the wafer to be detected is at the center of the camera scanning field of view of the machine stage, determine the expected coordinates of the next die in the machine stage coordinate system according to the reference coordinates of the reference die in the machine stage coordinate system;

[0346] Control the next die to be at the center of the camera scanning field of view according to the expected coordinates, calculate the actual coordinates of the next die in the machine stage coordinate system, and update the die interval and placement angle of the wafer to be detected according to the actual coordinates;

[0347] Recalculate the expected coordinates of the new next die according to the reference coordinates and the total moving distance of the machine stage, and loop through the process of updating the die interval and placement angle of the wafer to be detected until the total moving distance of the machine stage meets the preset conditions, and determine the die interval and placement angle obtained from the last update as the actual die interval and actual placement angle of the wafer to be detected.

[0348] The implementation principles and technical effects of the steps implemented when the computer program in the embodiments of the present application is executed by the processor are similar to the principles of the above wafer detection parameter determination method, and will not be elaborated here.

[0349] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0350] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0351] The above-described embodiments only represent several implementation manners of this application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application should be subject to the appended claims.

Claims

1. A method for determining wafer inspection parameters, characterized in that: The method comprises: When a wafer to be inspected is fixed on a platform and a reference grain in the wafer to be inspected is located at the center of a camera scanning field of view of the platform, determining the expected coordinates of the next grain in the platform coordinate system according to the reference coordinates of the reference grain in the platform coordinate system; Controlling the next die to be located at the center of the camera scanning field of view according to the expected coordinates, calculating the real coordinates of the next die in the machine coordinate system, and updating the die spacing and placement angle of the wafer to be inspected according to the real coordinates; According to the reference coordinates and the total moving distance of the machine, the expected coordinates of the new next grain are recalculated, and the process of updating the grain spacing and placement angle of the wafer to be inspected is cyclically executed until the total moving distance of the machine meets the preset conditions, and the grain spacing and placement angle obtained from the last update are determined as the actual grain spacing and actual placement angle of the wafer to be inspected.

2. The method according to claim 1, characterized in that The step of determining the expected coordinates of the next crystal grain in the machine coordinate system according to the reference coordinates of the reference crystal grain in the machine coordinate system comprises: Obtain the maximum accommodating die row and the maximum accommodating die column, the initial die spacing, and the initial placement angle within the effective field of view of the camera; Determine the expected coordinates of the next die in the machine coordinate system according to the reference coordinates, the maximum accommodating die row, the maximum accommodating die column, the initial die spacing and the initial placement angle.

3. The method according to claim 2, characterized in that The step of obtaining the maximum accommodating grain row and the maximum accommodating grain column, the initial grain spacing, and the initial placement angle within the effective field of view of the camera includes: Obtaining a starting point grain in a wafer template image of a wafer to be inspected; the wafer template image is obtained by splicing a plurality of grain images scanned according to a preset scanning trajectory; Taking the upper right corner of the starting point grain as the starting point of the grain search, sliding a distance of a grain width along the horizontal axis direction, searching for horizontal axis matching grains that match the pre-selected grain features, until the preset horizontal axis search stop condition is met, and obtaining the number of horizontal axis matching grains and the pixel coordinates of each horizontal axis matching grain; and taking the lower left corner of the starting point grain as the starting point of the grain search, sliding a distance of a grain height along the vertical axis direction, searching for vertical axis matching grains that match the grain features, until the preset vertical axis search stop condition is met, and obtaining the number of vertical axis matching grains and the pixel coordinates of each vertical axis matching grain; The maximum accommodating grain column is determined according to the number of grains matched on the horizontal axis, the maximum accommodating grain row is determined according to the number of grains matched on the vertical axis, and the initial grain spacing and the initial placement angle are determined according to the pixel coordinates of each grain matched on the horizontal axis and the pixel coordinates of each grain matched on the vertical axis.

4. The method according to any one of claims 1 to 3, characterized in that The next crystal grain is a valid crystal grain; and the calculating of the real coordinates of the next crystal grain in the machine coordinate system includes: Obtaining a position deviation between the reference grain and the next grain; According to the position deviation between the reference grain and the next grain, the expected coordinates of the next grain are calibrated, and the obtained calibrated coordinates are determined as the real coordinates of the next grain.

5. The method according to claim 4, characterized in that The obtaining of the position deviation between the reference grain and the next grain comprises: Searching for a matching grain that matches the pre-selected grain features according to a grain image taken when the next grain is at the center of the camera scanning field of view, and acquiring pixel coordinates of the matching grain; Determining pixel deviation coordinates of the matching grain relative to the center point of the image according to the pixel coordinates of the matching grain and the coordinates of the center point of the image of the grain map; The pixel deviation coordinates are converted according to the pixel pulse coefficient to obtain the position deviation between the reference grain and the next grain.

6. The method according to any one of claims 1 to 3, characterized in that The next crystal grain is an invalid crystal grain; and the calculating of the real coordinates of the next crystal grain in the machine coordinate system includes: If there is a valid grain in the grain map when the next grain is at the center of the camera scanning field of view, determining the real coordinates of the next grain according to the grain map and the expected coordinates of the next grain; If there is no valid grain in the grain map, the machine is controlled to move to reacquire the grain map, and the real coordinates of the next grain are determined according to the reacquired grain map and the expected coordinates of the next grain.

7. The method according to claim 6, characterized in that The controlling the machine to move and reacquire the grain map comprises: The machine is moved in the direction of the eight-connected domain centered on the current field of view by a grain distance equal to the field of view size, and the camera is controlled to scan the image to obtain the re-acquired grain map.

8. The method according to claim 7, characterized in that The step of determining the actual coordinates of the next grain according to the reacquired grain map and the expected coordinates of the next grain comprises: Searching for valid grains matching the pre-selected grain features in the re-acquired grain image, and acquiring pixel coordinates of the valid grains; Determine the real coordinates of the effective grain in the machine coordinate system according to the pixel coordinates of the effective grain, the image center coordinates of the grain map, the pixel pulse coefficient and the expected coordinates of the next grain; The real coordinates of the next grain are determined according to the real coordinates of the effective grains, the initial grain spacing, the maximum accommodating grain row and the maximum accommodating grain column within the effective field of view of the camera.

9. The method according to claim 8, characterized in that The determining the real coordinates of the next grain according to the real coordinates of the effective grain, the initial grain spacing, the maximum accommodating grain row and the maximum accommodating grain column within the effective field of view of the camera comprises: Determine the real coordinates of the mapped grain in the machine coordinate system according to the real coordinates of the effective grain, the number of grain intervals between the effective grain and the next grain, the initial grain interval, and the initial placement angle; the mapped grain is a grain in the re-acquired grain map having the same pixel coordinates as the next grain in the original field of view; Determining a moving distance of the machine according to the initial die spacing, the maximum accommodating die row, and the maximum accommodating die column; The real coordinates of the next grain are determined according to the difference between the real coordinates of the mapped grain and the moving distance.

10. The method according to any one of claims 1 to 3, characterized in that: The updating of the grain spacing and placement angle of the wafer to be inspected according to the real coordinates includes: Acquire the real coordinates of the previous next crystal grain in the machine coordinates; the previous next crystal grain is the next adjacent crystal grain before the next crystal grain; Determine the number of grain intervals between the previous next grain and the next grain according to the maximum grain row and the maximum grain column within the effective field of view of the camera and the number of field of view intervals between the previous next grain and the next grain; Determine the real distance between the previous next grain and the next grain according to the real coordinates of the previous next grain and the real coordinates of the next grain; The grain spacing and the placement angle are updated according to the number of grain spacings and the real distance.

Images