CN117672896A - Method and device for detecting arc scratches in wafer - Google Patents
Method and device for detecting arc scratches in wafer Download PDFInfo
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Abstract
The embodiment of the specification provides a method and a device for detecting arc scratches in a wafer. One embodiment of the method comprises the following steps: determining at least one abnormal region in the wafer image based on a plurality of abnormal dies contained in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies; removing non-target regions from the at least one abnormal region based on the width of the at least one abnormal region; performing arc fitting based on the position coordinates of the tube cores included in the remaining target area in the at least one abnormal area; and determining whether the target area forms an arc scratch or not according to the fitting result.
Description
Technical Field
The embodiments of the present disclosure relate to the field of micro-electromechanical system chip manufacturing, and in particular, to a method and apparatus for detecting circular arc scratches in a wafer.
Background
In the fabrication of mems chips, wafers (wafer) are the basic raw material for manufacturing chips. In the chip manufacturing process, the etched wafer needs to be polished. At this time, if particles fall or residues are present in the grinding table, arc scratches (arc scratches) are generated during the relative rotation of the grinding table and the wafer, and the chip yield is drastically reduced. Therefore, the arc-shaped scratch in the wafer is detected rapidly and accurately, root cause analysis is performed as soon as possible, and the arc-shaped scratch is an important link for controlling the reduction and expansion of the chip yield.
Disclosure of Invention
The embodiments of the present specification describe a method and apparatus for detecting circular arc scratches in a wafer, which can rapidly and accurately detect circular arc scratches in a wafer.
According to a first aspect, there is provided a method of detecting a circular arc type scratch in a wafer, comprising: determining at least one abnormal region in the wafer image based on a plurality of abnormal dies contained in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies; removing a non-target region from the at least one abnormal region based on a width of the at least one abnormal region; performing arc fitting based on the position coordinates of the tube cores included in the remaining target area in the at least one abnormal area; and determining whether the target area forms an arc scratch according to the fitting result.
According to a second aspect, there is provided an apparatus for detecting circular arc type scratches in a wafer, comprising: a first determination unit configured to determine at least one abnormal region in the wafer image based on a plurality of abnormal dies included in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies; an exclusion unit configured to exclude a non-target area from the at least one abnormal area based on a width of the at least one abnormal area; a fitting unit configured to perform arc fitting based on position coordinates of a die included in a target region remaining in the at least one abnormal region; and a second determination unit configured to determine whether the target area forms a circular arc scratch according to a fitting result.
According to a third aspect, there is provided a computer readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform a method as described in any of the implementations of the first aspect.
According to a fourth aspect, there is provided a computing device comprising a memory and a processor, wherein the memory has executable code stored therein, and wherein the processor, when executing the executable code, implements a method as described in any of the implementations of the first aspect.
According to the method and the device for detecting the circular arc scratches in the wafer, at least one abnormal region in the wafer image is determined according to a plurality of abnormal dies contained in the wafer image, non-target regions are eliminated from the at least one abnormal region based on the width of the abnormal region, circular arc fitting is performed based on the position coordinates of the dies contained in the remaining target regions, and finally whether the target regions form the circular arc scratches is determined according to the fitting result. Because part of non-target areas are eliminated based on the width of the abnormal areas before arc fitting is performed, the number of the abnormal areas in subsequent processing is reduced, and the detection efficiency of arc scratches in the wafer is improved.
Drawings
FIG. 1 shows a schematic diagram of one application scenario in which embodiments of the present description may be applied;
FIG. 2 illustrates a flowchart for detecting circular arc scratches in a wafer, according to one embodiment;
fig. 3 (a) shows an exemplary diagram of mapping the number of abnormal dies of the abnormal region to the coordinate axis by taking the abnormal region 1011 as an example;
FIG. 3 (b) shows an example diagram of mapping the number of abnormal dies of the abnormal region to coordinate axes using the abnormal region 1012 as an example;
FIG. 4 shows a schematic diagram of an example of a common edge;
FIG. 5 shows a schematic diagram of smoothing the position coordinates of a plurality of dies;
FIG. 6 shows a schematic diagram of the center coordinates and radius of curvature of a circle labeled and fitted on a wafer image;
fig. 7 shows a schematic block diagram of an apparatus for detecting circular arc scratches in a wafer, according to one embodiment.
Detailed Description
The technical scheme provided in the present specification is further described in detail below with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings. It should be noted that, without conflict, the embodiments of the present specification and features in the embodiments may be combined with each other.
In practice, the produced wafer may have various defects, and some defects have the same generation mechanism and are converged into one piece to form a certain specific pattern, so that the pattern characteristics of the wafer are researched, the cause of the pattern is analyzed, and the wafer is beneficial to improving the process and improving the chip yield. As described above, when polishing a wafer, if particles fall off or residues remain in the polishing pad, arc scratches are generated during the relative rotation between the polishing pad and the wafer. Therefore, the arc scratches in the wafer are detected rapidly and accurately, the improvement of the process is facilitated, and the chip yield is improved.
For this reason, the embodiments of the present disclosure provide a method for detecting circular arc scratches in a wafer, which can rapidly and accurately detect circular arc scratches in a wafer. Fig. 1 shows a schematic diagram of one application scenario in which embodiments of the present description may be applied. As shown in fig. 1, first, a wafer image 101 may be acquired, each small lattice on the wafer image 101 may represent one die (die), and a plurality of abnormal dies (abnormal die) may be included in the wafer image 101, and the abnormal dies may refer to dies that are detected to have defects. In the example shown in fig. 1, black squares may represent abnormal dies and white squares may represent normal dies. Then, based on the plurality of abnormal dies included in the wafer image 101, the abnormal region 1011, the abnormal region 1012, and the abnormal region 1013 in the wafer image 101 can be specified, and the abnormal region 1011, the abnormal region 1012, and the abnormal region 1013 are regions formed by connecting the abnormal dies. Since the trace length of the circular arc-shaped scratch should have the lowest value, the number of abnormal dies contained in the abnormal region should have a lower threshold value, in this example, the number of abnormal dies contained in the abnormal region is not less than 6. Then, based on the widths of the abnormal region 1011, the abnormal region 1012, and the abnormal region 1013, the non-target region is excluded from the three abnormal regions. In this example, since the width of the abnormal region 1013 is too wide, the characteristic of the arc scratch is not significantly satisfied, and therefore the abnormal region 1013 is excluded as a non-target region, and the abnormal region 1011 and the abnormal region 1012 are reserved as target regions. Then, arc fitting is performed based on the position coordinates of the die included in the abnormal region 1011 and the abnormal region 1012. Finally, it is determined that the abnormal region 1011 and the abnormal region 1012 form a circular arc scratch according to the fitting result of the circular arc fitting.
With continued reference to fig. 2, fig. 2 illustrates a flowchart of a method of detecting circular arc type scratches in a wafer, according to one embodiment. It is understood that the method may be performed by any apparatus, device, platform, cluster of devices having computing, processing capabilities. As shown in fig. 2, the method for detecting a circular arc scratch in a wafer may include the following steps 201 to 204, specifically:
at step 201, at least one anomaly region in the wafer image is determined based on a plurality of anomaly dies contained in the wafer image.
In this embodiment, a wafer image of a wafer may be acquired, and the wafer image may include a plurality of abnormal dies. Here, the wafer is a carrier for designing an integrated circuit, and an analog circuit or a digital circuit designed by people are finally implemented on the wafer. Each small cell on each wafer is a complete chip circuit unit, such as a CPU or a memory, known as a Die (Die). Here, the abnormal die may refer to a die detected to have a defect, wherein the defect may include various types of defects that may occur on the wafer, such as redundancy of the wafer surface, mechanical scratches, and the like. In this example, each die may be displayed as a small square in the wafer image. At least one abnormal region in the wafer image may be determined from a plurality of abnormal dies contained in the wafer image, wherein the abnormal region may be a region formed by connecting the abnormal dies. For example, connectivity analysis may be performed on a plurality of tiles in the wafer image that represent abnormal dies, for example, using an 8-pass mode to pass a tile corresponding to an abnormal die with tiles corresponding to abnormal dies in 8 directions around it (including: up, down, left, right, up-left, up-right, down-left, down-right), thereby obtaining at least one abnormal region.
In practice, the trace length of the circular arc-shaped scratch should have the lowest value according to the characteristics of the circular arc-shaped scratch, and thus the number of abnormal dies contained in the abnormal region should have a lower threshold value. Thus, in some implementations, step 201 may specifically include: step (1), connectivity analysis is carried out on a plurality of abnormal tube cores, and at least one abnormal region formed by connecting the abnormal tube cores is obtained; and (2) removing the abnormal areas with the number of the contained dies less than a first threshold value to obtain at least one abnormal area.
In this implementation manner, the first threshold in the step (2) may be preset according to actual needs, for example, the first threshold may be set to 6, 8, or the like. Through the implementation mode, abnormal areas which do not accord with the characteristics of the arc scratch can be removed simply and quickly.
Step 202, excluding non-target areas from the at least one abnormal area based on the width of the at least one abnormal area.
In this embodiment, the width of the circular arc type scratch is generally not too wide, as is known from the characteristics of the circular arc type scratch. Taking the abnormal region 1013 in fig. 1 as an example, the abnormal region 1013 is significantly too wide to conform to the characteristics of a circular arc scratch. Therefore, the abnormal region 1013 can be excluded as a non-target region, and the subsequent arc fitting is not performed, thereby improving the calculation speed. In practice, it may be determined in various ways whether the width of one abnormal area is too wide.
In one implementation, it is found through analysis that there is a certain association between the width of the abnormal region and the number of abnormal dies contained in the rows and columns in the abnormal region. For example, if the number of abnormal dies contained in most of the rows or columns in the abnormal region is relatively large, the width of the abnormal region may be large, and the shape of the abnormal region may be biased toward a sheet shape rather than a circular arc shape. Based on this, the above step 202 may specifically include the following steps (a) -step (c), specifically:
step (a), counting, for each of at least one anomaly region, a first proportion of rows in the anomaly region that have a number of dies exceeding a second threshold and a second proportion of columns in the anomaly region that have a number of dies exceeding the second threshold.
In the present embodiment, as a statistical method, fig. 3 (a) shows an example diagram in which the number of abnormal dies in the abnormal region 1011 is mapped to the coordinate axis by taking the abnormal region 1011 as an example. In the example shown in fig. 3 (a), the number of abnormal dies included in each column of the abnormal region 1011 may be mapped to the X axis, and the number of abnormal dies included in each row may be mapped to the Y axis. As also shown in fig. 3 (b), fig. 3 (b) shows an example diagram of mapping the number of abnormal dies of the abnormal region to the coordinate axis, taking the abnormal region 1012 as an example. In the example shown in fig. 3 (b), the number of abnormal dies included in each column of the abnormal region 1012 may be mapped to the X-axis, and the number of abnormal dies included in each row may be mapped to the Y-axis. As can be seen from the examples shown in fig. 3 (a) and 3 (b), the larger the number of abnormal dies, the larger the value of the map.
Then, according to the mapping result of the abnormal die number on the coordinate axis, a first proportion of rows with the die number exceeding a second threshold value in each abnormal region and a second proportion of columns with the die number exceeding the second threshold value can be counted. Here, the above-mentioned second threshold value may be set according to actual conditions, and for example, the second threshold value may be determined according to a statistical value (for example, a mean value, a median value, etc.) of the number of abnormal dies of the rows and columns of the arc-shaped scratch determined. For another example, the second threshold may be set based on human experience, e.g., the second threshold is set to 2.
And (b) determining a judgment index according to the first proportion and the second proportion.
In this implementation, the determination index may be determined in a plurality of manners according to the first ratio and the second ratio obtained by statistics. For example, a smaller one of the first and second ratios may be used as the determination index. For another example, the average of the first proportion and the second proportion may be used as the determination index.
And (c) in response to determining that the determination index exceeds the third threshold, determining that the width of the abnormal region does not conform to the circular arc type scratch.
In this implementation, the third threshold may be preset according to actual needs, for example, the third threshold is set to 0.3. Then, whether the judgment index corresponding to each abnormal region exceeds a third threshold value is judged, if the judgment index exceeds a certain abnormal region, the abnormal region is larger in width and does not conform to the arc scratch, and therefore the abnormal region is determined not to be a target region and can be eliminated as a non-target region.
In another implementation, the analysis finds that there is a certain correlation between the width of the anomaly region and the number of common edges between the anomaly dies in the anomaly region. In general, a larger number of common edges means a denser distribution of abnormal dies, a larger width of an abnormal region, and a shape of the abnormal region is biased to a sheet shape rather than a circular arc shape. Based on this, the above step 202 may further specifically include the following steps S1 to S3, specifically:
step S1, counting the total number of the dies in the abnormal region and the number of the shared edges owned by each die for each abnormal region in at least one abnormal region.
In this implementation, a common edge may refer to an adjacent edge between two dies. As shown in fig. 4, fig. 4 shows a schematic diagram of an example of a common edge. In the example shown in fig. 4, for the abnormal dies A, B and C in the abnormal region 1012, there is a common edge between a and B, and a common edge between B and C. In this example, the common edges are represented by gray rectangles.
And S2, taking the dies with the number of the shared edges exceeding a fourth threshold as characteristic dies, and determining the ratio of the number of the characteristic dies to the total number of the dies in the abnormal area.
In this embodiment, the fourth threshold may be set according to the actual situation, and for example, the fourth threshold may be set to 3. Here, the ratio between the number of feature dies in each anomaly region and the total number of dies in that anomaly region may be calculated.
And step S3, in response to the fact that the determined ratio exceeds a fifth threshold value, determining that the width of the abnormal region does not accord with the arc-shaped scratch, and determining that the abnormal region is not a target region.
In this embodiment, the fifth threshold may be set according to the actual situation, and for example, the fifth threshold may be set to 0.2. And judging whether the ratio corresponding to each abnormal region exceeds a fifth threshold value, if so, indicating that the width of the abnormal region is larger and does not accord with the arc scratch, wherein the abnormal region is not a target region and can be excluded as a non-target region.
As other implementations, the total number of shared edges of all shared edges contained in the anomaly region may also be counted. Thereafter, the ratio between the total number of edges and the total number of dies in the abnormal area is calculated. If the ratio is greater than a preset threshold (e.g., 1.05), it indicates that the width of the abnormal region is large, the arc-shaped scratch is not met, the abnormal region is not a target region, and the abnormal region can be excluded as a non-target region.
In step 203, arc fitting is performed based on the position coordinates of the die included in the target area remaining in the at least one abnormal area.
In this embodiment, the wafer image may be mapped into a two-dimensional coordinate system, so as to obtain the position coordinates of each die in the target area, for example, the coordinates of four vertices of the small square corresponding to the die, the coordinates of the center point, and so on. Then, arc fitting may be performed based on the position coordinates of the die in the target area, for example, various arc fitting algorithms may be used to perform arc fitting on the center point coordinates or the vertex coordinates of the die in the target area, where the fitting result may be a segment of an arc, and the fitting result may include the center coordinates, the radius of curvature, and the like of the arc.
It will be appreciated that when selecting the center point coordinates or the vertex coordinates of the die for circular arc fitting, the tendency of circular arc type scratches is easily blurred due to the limited number of dies in the target area. In order to enhance the fitting effect of the arc fitting, the position coordinates of the abnormal die in the target area can be processed before the arc fitting is performed, so that a better fitting effect is obtained. At this time, step 203 may specifically include: step 1), smoothing the position coordinates of a plurality of dies in a target area to obtain smoothed coordinate points; and 2) performing arc fitting on the coordinate points.
In this implementation, the smoothing process may refer to merging the coordinates of the center points of the adjacent dies in the target area into one coordinate, where the value of the coordinate is the midpoint of the coordinates of the two center points, that is, the midpoint of the common edge of the adjacent dies. As shown in fig. 5, fig. 5 shows a schematic diagram of smoothing the position coordinates of a plurality of dies. In fig. 5, for example, the abnormal dies A, B and C in the abnormal region 1012, the coordinates of the center points of the adjacent die a and die B are combined as the coordinates M, and the coordinates of the center points of the adjacent die B and die C are combined as the coordinates N. And so on, the position coordinates of the multiple dies in the abnormal region 1012 may be smoothed to obtain multiple coordinate points. And then, the obtained plurality of coordinate points can be used as the position coordinates of the tube core included in the target area, and arc fitting can be carried out on the plurality of coordinate points, so that a fitting result with better fitting effect can be obtained.
In some implementations, the above step 2) may be specifically performed as follows: and adopting a least square method to perform arc fitting on the coordinate points.
In practice, the least squares method can quickly and accurately fit trends and rules in the data, however, the least squares method is more sensitive to outliers. Since the plurality of coordinate points used in the arc fitting according to the present embodiment are coordinate points obtained based on the position coordinates of the die in the same abnormal region, there is less possibility that abnormal points exist. Therefore, the plurality of coordinate points are more suitable for arc fitting by using a least square method.
Step 204, determining whether the target area forms arc scratches according to the fitting result.
In this embodiment, based on the fitting result, whether or not the target area forms a circular arc scratch may be determined in various ways. For example, it may be determined whether the target area forms a circular arc type scratch based on only the standard deviation between the position coordinates of the die in the target area and the fitting result. For example, when the standard deviation is greater than a certain preset threshold value, it may be determined that the target area cannot form a circular arc scratch; when the standard deviation is less than or equal to the threshold value, it may be determined that the target area forms a circular arc type scratch.
In some implementations, it may further be determined whether the target area forms a circular arc scratch according to the following steps (one) to (four), specifically:
step (one), calculate the standard deviation between die and fit result in the goal area.
In this implementation, the standard deviation between the position coordinates of the die in the target area and the fitting result may be calculated. Here, the standard deviation may be used to describe the fitting degree level, and may reflect the magnitude of the fitting error, and the smaller the standard deviation, the higher the fitting accuracy is proved.
And (II) determining that the target area does not form the circular arc scratch in response to determining that the standard deviation exceeds the sixth threshold.
In this implementation manner, it may be further determined whether the standard deviation calculated in the step (one) exceeds a preset sixth threshold, and if the standard deviation exceeds the sixth threshold, it is determined that the target area does not form a circular arc scratch. Thus, it can be rapidly judged from the standard deviation that those target areas cannot form circular arc scratches by the step (one) and the step (two).
And step three, in response to determining that the standard deviation does not exceed the sixth threshold, further determining whether the radius of curvature and the standard deviation of the fitting result are within a preset range.
It has been found by analysis that the radius of curvature of the circular arc scratches on the wafer is generally not particularly large nor particularly small. Typically between one wafer radius and several wafer radii, e.g., [0.8,5]. Therefore, the range of curvature radius can be empirically preset. The range of values of the standard deviation may also be empirically preset. In this way, in the case where the standard deviation does not exceed (e.g., is less than or equal to) the sixth threshold value, it can be further determined whether the radius of curvature and the standard deviation of the fitting result are both within the corresponding range of values.
And step four, determining that the target area forms a circular arc scratch in response to the fact that the curvature radius and the standard deviation of the fitting result are determined to be in a preset range.
In this implementation manner, when the curvature radius of the fitting result and the standard deviation calculated in the step (a) are both within the corresponding value range, it may be determined that the target area forms a circular arc scratch. In the implementation mode, whether the target area forms the arc scratch or not can be judged through the curvature radius and the standard deviation, so that the judging result is more accurate.
In some implementations, the method for detecting the circular arc scratches in the wafer may further include marking on the wafer image according to circle center coordinates and curvature radius of the circular arc obtained by fitting the circular arc in response to determining that the target area forms the circular arc scratches, which are not shown in fig. 2.
In this implementation manner, when the target area forms the arc scratch, the wafer image may be marked in various manners according to the center coordinates and the radius of curvature of the arc obtained by arc fitting. For example, the center coordinates and radius of curvature of the arc may be annotated on the wafer image in text form. For example, the circle arc obtained by fitting may be displayed on the wafer image, and on the basis of this, the center coordinates, the radius of curvature, and the like corresponding to the circle arc may be displayed. Through the implementation mode, the information such as the circle center coordinates, the curvature radius and the like of the circular arc obtained by fitting the circular arc can be displayed on the wafer image, so that a user can obtain the information. As shown in fig. 6, fig. 6 shows a schematic diagram of circle center coordinates and curvature radius of an arc obtained by labeling fitting on a wafer image. It should be understood that the content, form, location, etc. of the information labeled in fig. 6 are merely illustrative, and are not limiting of the content, form, location, etc. of the information labeled. In practice, the content, form, location, etc. of the marked information can be set according to actual needs.
Referring back to the above procedure, in the embodiment of the present specification, at least one abnormal region in the wafer image is first determined from a plurality of abnormal dies contained in the wafer image, then a non-target region is excluded from the at least one abnormal region based on the width of the abnormal region, and arc fitting is performed based on the position coordinates of the dies included in the remaining target region, and finally whether the target region forms an arc scratch is determined according to the fitting result. Because part of non-target areas are eliminated based on the width of the abnormal areas before arc fitting is performed, the number of the abnormal areas in subsequent processing is reduced, and the detection efficiency of arc scratches in the wafer is improved.
According to another embodiment, an apparatus for detecting circular arc type scratches in a wafer is provided. The device for detecting the circular arc scratch in the wafer can be deployed in any equipment, platform or equipment cluster with computing and processing capabilities.
Fig. 7 shows a schematic block diagram of an apparatus for detecting circular arc scratches in a wafer, according to one embodiment. As shown in fig. 7, the apparatus 700 for detecting a circular arc scratch in a wafer includes: a first determining unit 701 configured to determine at least one abnormal region in the wafer image based on a plurality of abnormal dies included in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies; an exclusion unit 702 configured to exclude a non-target area from the at least one abnormal area based on a width of the at least one abnormal area; a fitting unit 703 configured to perform arc fitting based on position coordinates of the die included in the target region remaining in the at least one abnormal region; a second determining unit 704 configured to determine whether the target area forms a circular arc scratch according to a fitting result.
In some optional implementations of this embodiment, the apparatus 700 further includes: and a labeling unit (not shown in the figure) configured to label the wafer image according to the center coordinates and the curvature radius of the arc obtained by fitting the arc in response to determining that the target region forms the arc scratch.
In some optional implementations of the present embodiment, the first determining unit 701 is further configured to: connectivity analysis is carried out on the plurality of abnormal tube cores to obtain at least one abnormal region formed by connecting the abnormal tube cores; and removing the abnormal areas with the number of the contained dies less than the first threshold value to obtain at least one abnormal area.
In some optional implementations of the present embodiment, the exclusion unit 702 is further configured to: for each abnormal region in the at least one abnormal region, counting a first proportion of rows of the abnormal region, the number of the dies of which exceeds a second threshold value, and a second proportion of columns of the abnormal region, the number of the dies of which exceeds the second threshold value; determining a determination index according to the first proportion and the second proportion; in response to determining that the above-mentioned determination index exceeds a third threshold value, it is determined that the width of the abnormal region does not conform to the circular arc type scratch, and it is determined that the abnormal region is not a target region.
In some optional implementations of the present embodiment, the exclusion unit 702 is further configured to: counting the total number of dies in the abnormal region and the number of shared edges owned by each die for each abnormal region in the at least one abnormal region, wherein the shared edges refer to adjacent edges between two dies; taking the dies with the number of the shared edges exceeding a fourth threshold as characteristic dies, and determining the ratio between the number of the characteristic dies and the total number; in response to determining that the ratio exceeds a fifth threshold, it is determined that the width of the abnormal region does not conform to the circular arc type scratch, and it is determined that the abnormal region is not the target region.
In some optional implementations of the present embodiment, the second determining unit 704 is further configured to: calculating a standard deviation between the die in the target area and the fitting result; in response to determining that the standard deviation exceeds a sixth threshold, it is determined that the target area does not form a circular arc scratch.
In some optional implementations of the present embodiment, the second determining unit 704 is further configured to: in response to determining that the standard deviation does not exceed the sixth threshold, further determining whether a radius of curvature of the fitting result and the standard deviation are within a preset range; and determining that the target area forms a circular arc scratch in response to determining that the radius of curvature of the fitting result and the standard deviation are within the preset range.
In some alternative implementations of the present embodiment, the fitting unit 703 includes: a smoothing unit (not shown) configured to perform smoothing processing on the position coordinates of the plurality of dies in the target area to obtain smoothed plurality of coordinate points; and an arc fitting unit (not shown in the figure) configured to perform arc fitting on the plurality of coordinate points.
In some optional implementations of this embodiment, the arc fitting unit is further configured to: and performing arc fitting on the coordinate points by adopting a least square method.
According to an embodiment of another aspect, there is also provided a computer-readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform the method described in fig. 2.
According to an embodiment of yet another aspect, there is also provided a computing device including a memory and a processor, wherein the memory has executable code stored therein, and the processor, when executing the executable code, implements the method described in fig. 2.
Those of ordinary skill would further appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be embodied in electronic hardware, in computer software, or in a combination of the two, and that the elements and steps of the examples have been generally described in terms of function in the foregoing description to clearly illustrate the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Those of ordinary skill in the art may implement the described functionality using different approaches for each particular application, but such implementation is not to be considered as beyond the scope of the present application.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in hardware, in a software module executed by a processor, or in a combination of the two. The software modules may be disposed in Random Access Memory (RAM), memory, read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A method of detecting circular arc scratches in a wafer, comprising:
determining at least one abnormal region in the wafer image based on a plurality of abnormal dies contained in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies;
removing non-target regions from the at least one abnormal region based on the width of the at least one abnormal region;
performing arc fitting based on the position coordinates of the tube cores included in the remaining target area in the at least one abnormal area;
and determining whether the target area forms an arc scratch or not according to the fitting result.
2. The method of claim 1, wherein the method further comprises:
and responding to the determination that the target area forms an arc scratch, and marking on the wafer image according to the circle center coordinates and the curvature radius of the arc obtained by arc fitting.
3. The method of claim 1, wherein the determining at least one anomaly region in the wafer image based on a plurality of anomaly dies contained in the wafer image comprises:
connectivity analysis is carried out on the plurality of abnormal tube cores, so that at least one abnormal region formed by connecting the abnormal tube cores is obtained;
and removing the abnormal areas with the number of the contained dies less than the first threshold value to obtain at least one abnormal area.
4. The method of claim 1, wherein the excluding non-target regions from the at least one anomaly region based on a width of the at least one anomaly region comprises:
for each of the at least one anomaly region, counting a first proportion of rows in the anomaly region for which the number of dies exceeds a second threshold and a second proportion of columns in the anomaly region for which the number of dies exceeds the second threshold;
determining a judgment index according to the first proportion and the second proportion;
in response to determining that the determination index exceeds a third threshold, determining that the width of the abnormal region does not conform to the circular arc type scratch, and determining that the abnormal region is not a target region.
5. The method of claim 1, wherein the excluding non-target regions from the at least one anomaly region based on a width of the at least one anomaly region comprises:
counting the total number of dies in the abnormal region and the number of shared edges owned by each die for each abnormal region in the at least one abnormal region, wherein the shared edges refer to adjacent edges between two dies;
taking the dies with the number of the shared edges exceeding a fourth threshold as characteristic dies, and determining the ratio between the number of the characteristic dies and the total number;
in response to determining that the ratio exceeds a fifth threshold, determining that the width of the abnormal region does not conform to the arcuate scratch, and determining that the abnormal region is not the target region.
6. The method of claim 1, wherein the determining whether the target area forms a circular arc scratch according to the fitting result comprises:
calculating a standard deviation between the die in the target area and the fitting result;
in response to determining that the standard deviation exceeds a sixth threshold, it is determined that the target region does not form a circular arc scratch.
7. The method of claim 6, wherein the determining whether the target area forms a circular arc scratch according to the fitting result further comprises:
in response to determining that the standard deviation does not exceed the sixth threshold, further determining whether a radius of curvature of the fitting result and the standard deviation are within a preset range;
and determining that the target area forms a circular arc scratch in response to determining that the curvature radius of the fitting result and the standard deviation are in the preset range.
8. The method of claim 1, wherein the performing a circular arc fit based on the position coordinates of the die included in the remaining target area of the at least one anomaly area comprises:
smoothing the position coordinates of a plurality of dies in the target area to obtain smoothed coordinate points;
and performing arc fitting on the coordinate points.
9. The method of claim 8, wherein the performing an arc fit to the plurality of coordinate points comprises:
and adopting a least square method to perform arc fitting on the coordinate points.
10. An apparatus for detecting circular arc scratches in a wafer, comprising:
a first determining unit configured to determine at least one abnormal region in a wafer image based on a plurality of abnormal dies contained in the wafer image, wherein the abnormal region is a region formed by connecting the abnormal dies;
an exclusion unit configured to exclude a non-target area from the at least one abnormal area based on a width of the at least one abnormal area;
a fitting unit configured to perform arc fitting based on position coordinates of dies included in a target area remaining in the at least one abnormal area;
and a second determination unit configured to determine whether the target area forms a circular arc scratch according to a fitting result.
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| CN202311673904.6A CN117672896A (en) | 2023-12-06 | 2023-12-06 | Method and device for detecting arc scratches in wafer |
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| CN202311673904.6A CN117672896A (en) | 2023-12-06 | 2023-12-06 | Method and device for detecting arc scratches in wafer |
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