Contour point processing method and device, medium and product

Abstract

The invention discloses a contour point processing method, contour point processing equipment, a medium and a product, which are applied to the technical field of photoetching modeling. The method comprises the following steps: firstly, extracting a first point sequence of a photoresist pattern, and then filtering out abnormal points in the first point sequence to obtain a second point sequence; finally, redundant points in the second point sequence are filtered out, and a third point sequence is obtained. In the implementation mode, the first point sequence is filtered in two steps, and in the first step, the abnormal contour points are filtered through the first threshold value, so that the accuracy of the residual contour points is ensured, and the photoetching model with higher accuracy can be obtained. And in the second step, redundant contour points are filtered out through a second threshold value, so that the data volume is reduced, and the modeling speed is ensured. According to the scheme, abnormal points and redundant points are filtered out by using the position relation between the first point pair and each intermediate point and the position relation between the second point pair and each intermediate point, so that the data volume is reduced, the data accuracy is ensured, and the modeling speed and accuracy are improved.

Description

Technical Field

[0001] The present application belongs to the field of photolithography modeling technology, and in particular, relates to a contour point processing method, equipment, medium and product. Background Art

[0002] When using key dimension information for photolithography modeling, the data ignores more complex two-dimensional structures such as corners and joints, as well as information on tilted graphics. Therefore, the contour information (multiple contour points) of the photoresist graphics is often extracted through scanning electron microscope (SEM) images. This contour information is then used for modeling to supplement the missing information of complex environments.

[0003] However, due to algorithm limitations, the currently extracted contour points are not only too numerous, but also contain some abnormal points, which will lead to inefficiency and low model accuracy when modeling based on the extracted contour points. Summary of the invention

[0004] The embodiments of the present application provide a contour point processing method, device, medium and product, which can improve modeling efficiency and accuracy when modeling based on extracted contour points.

[0005] On the one hand, an embodiment of the present application provides a contour point processing method, comprising:

[0006] Extracting the contour points of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence;

[0007] Filter out the abnormal points in the first point sequence to obtain a second point sequence; the abnormal points are contour points that meet a first preset condition; the first preset condition includes that there is only one first intermediate point between the first point pair in the first point sequence, and the first distance corresponding to the first intermediate point is greater than a first threshold; the first point pair is determined from the first point sequence using the Douglas-Peucker algorithm based on the first threshold; the first distance is the distance from the first intermediate point to a first straight line, and the first straight line is the straight line where the first point pair is located;

[0008] Redundant points in the second point sequence are filtered out to obtain a third point sequence; the redundant points are contour points in the second point sequence that are located between second point pairs that meet a second preset condition; the second preset condition includes that the distance from each second intermediate point to the second straight line is less than a second threshold; the second intermediate points include contour points in the second point sequence that are located between second point pairs; the second point pairs are determined from the second point sequence using the Douglas-Peucker algorithm based on the second threshold; the second straight line is the straight line where the second point pair is located.

[0009] On the other hand, filtering out abnormal points in the first point sequence to obtain a second point sequence includes:

[0010] Acquire a starting point and an ending point in the first point sequence as the first point pair;

[0011] Acquire the maximum distance between each contour point located between the first point pair in the first point sequence and the first straight line as a first distance;

[0012] In the case where the first distance is greater than the first threshold, the contour point corresponding to the first distance is respectively combined with the two contour points of the first point pair to form two new first point pairs; and the maximum distance between each contour point between the first point pair in the first point sequence and the first straight line is obtained as the first distance; until there is no contour point whose distance from the first straight line is greater than the first threshold among the contour points between the first point pair in the first point sequence;

[0013] Determine the contour points that meet the first preset condition as the abnormal points;

[0014] The abnormal points in the first point sequence are filtered out to obtain the second point sequence.

[0015] On the other hand, filtering out redundant points in the second point sequence to obtain a third point sequence includes:

[0016] Obtaining a starting point and an ending point in the second point sequence as the second point pair;

[0017] Acquire the maximum distance between each contour point located between the second point pair in the second point sequence and the second straight line as the second distance;

[0018] In the case where the second distance is greater than the second threshold, the contour point corresponding to the second distance is respectively combined with the two contour points of the second point pair to form two new second point pairs; and the maximum distance between each contour point between the second point pair in the second point sequence and the second straight line is returned to the step of obtaining the maximum distance between each contour point between the second point pair in the second point sequence and the second straight line as the second distance; until there is no contour point whose distance to the second straight line is greater than the second threshold among each contour point between the second point pair in the second point sequence;

[0019] Determine each contour point between the second point pairs satisfying the second preset condition in the second point sequence as the redundant point;

[0020] The redundant points in the second point sequence are filtered out to obtain the third point sequence.

[0021] On the other hand, extracting the contour points of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence includes:

[0022] Establish multiple initial points;

[0023] Based on the outline of the photoresist pattern in the scanning electron microscope image, each of the initial points is moved to obtain the first point sequence.

[0024] On the other hand, after moving each of the initial points based on the profile of the photoresist pattern in the scanning electron microscope image to obtain the first point sequence, the method further includes:

[0025] Determining the moving distance of each of the initial points toward the outline of the photoresist pattern;

[0026] The first threshold is determined based on the moving distance.

[0027] On the other hand, after moving each of the initial points based on the outline of the photoresist pattern in the scanning electron microscope image to obtain the first point sequence, the method further includes:

[0028] For each of the contour points, determining the curvature of each contour point based on the adjacent contour points of the contour point;

[0029] Based on each of the curvatures, the second threshold is determined.

[0030] On the other hand, the photoresist pattern is a closed pattern;

[0031] Acquiring a starting point and an ending point in the first point sequence as the first point pair includes:

[0032] Selecting any two adjacent contour points on the photoresist pattern in the first point sequence as the starting point and the ending point of the first point sequence;

[0033] or,

[0034] Acquiring a starting point and an ending point in the second point sequence as the second point pair includes:

[0035] Any two adjacent contour points on the photoresist pattern are selected in the second point sequence as the starting point and the ending point of the second point sequence.

[0036] On the other hand, the photoresist pattern is a non-closed pattern;

[0037] Acquiring a starting point and an ending point in the first point sequence as the first point pair includes:

[0038] Selecting two contour points at both ends of the photoresist pattern in the first point sequence as the starting point and the ending point of the second point sequence;

[0039] or,

[0040] Acquiring a starting point and an ending point in the second point sequence as the second point pair includes:

[0041] Two contour points at both ends of the photoresist pattern are selected in the second point sequence to serve as the starting point and the ending point of the second point sequence.

[0042] In another aspect, an embodiment of the present application provides a contour point processing device, comprising: a processor and a memory storing computer program instructions;

[0043] When the processor executes the computer program instructions, the contour point processing method described above is implemented.

[0044] On the other hand, an embodiment of the present application provides a computer-readable storage medium, on which computer program instructions are stored. When the computer program instructions are executed by a processor, the contour point processing method described above is implemented.

[0045] On the other hand, an embodiment of the present application provides a computer program product. When instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the contour point processing method as described above.

[0046] A method for processing contour points provided in an embodiment of the present application first extracts a first point sequence of a photoresist pattern, then filters out abnormal points in the first point sequence to obtain a second point sequence; finally, filters out redundant points in the second point sequence to obtain a third point sequence. In this implementation, the first point sequence is filtered in two steps. In the first step, abnormal contour points are filtered out by a first threshold value, thereby ensuring the accuracy of the remaining contour points, and thus a more accurate lithography model can be obtained. In the second step, redundant contour points are filtered out by a second threshold value, thereby reducing the amount of data and ensuring the modeling speed. This solution specifically utilizes the positional relationship between the first point pair and the second point pair and each intermediate point to filter out abnormal points and redundant points, which not only reduces the amount of data, but also ensures the accuracy of the data, thereby improving the speed and accuracy of modeling. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] Figure 1A schematic diagram of a flow chart of a contour point processing method provided by an embodiment of the present application is shown;

[0049] Figure 2 A schematic diagram of the process of the Douglas-Peucker algorithm provided by an embodiment of the present application is shown;

[0050] Figure 3 A schematic diagram of performing the first iteration on a specific contour point sequence using the Douglas-Peucker algorithm provided by an embodiment of the present application is shown;

[0051] Figure 4 A schematic diagram of performing a second iteration on a specific contour point sequence using the Douglas-Peucker algorithm provided by an embodiment of the present application is shown;

[0052] Figure 5 A schematic diagram of performing a third iteration on a specific contour point sequence using the Douglas-Peucker algorithm provided by an embodiment of the present application is shown;

[0053] Figure 6 A schematic diagram of performing the fourth iteration on a specific contour point sequence using the Douglas-Peucker algorithm provided by an embodiment of the present application is shown;

[0054] Figure 7 A schematic diagram of a method for extracting contour points of a first photoresist pattern provided by an embodiment of the present application is shown;

[0055] Figure 8 A schematic diagram of a method for extracting contour points of a second photoresist pattern provided by an embodiment of the present application is shown;

[0056] Fig. 9 A schematic diagram of the hardware structure of a contour point processing device provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0057] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0058] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "include..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0059] Ideally, the imaging pattern of the silicon wafer should be consistent with the pattern of the mask. However, as the semiconductor technology node gradually shrinks, the critical dimension (CD) of the mask pattern is smaller than the exposure wavelength, which will cause differences between the two patterns. Therefore, compensation for the optical proximity effect becomes essential. To solve the optical proximity effect, optical proximity effect correction technology is widely used.

[0060] In the optical proximity correction process, a key step is to collect actual exposure and development data based on the current photolithography process, so as to establish a photoresist model that can predict the photoresist patterns of different masks under the current process. Therefore, the accuracy of the photoresist model is crucial for the manufacture of the final mask in optical proximity correction and the reduction of defects. The photoresist model is not a strict simulation, but a compact model that is semi-physical and semi-empirical. In this context, accurately and efficiently providing measurement data is the key to establishing a photoresist model that can accurately predict.

[0061] Generally speaking, the data required to establish a photoresist model is measured by measuring the feature size using a scanning electron microscope (Critical Dimension Scanning Electron Microscope, CD-SEM). The test pattern mask is manufactured based on the designed pattern, and exposed and developed under the actual process. Finally, the size of the photoresist pattern is measured by CD-SEM to obtain the critical size of the test pattern at a certain position.

[0062] This method is currently widely used and can provide the one-dimensional size of the measured position more accurately and conveniently. However, modeling through CD ignores the more complex two-dimensional structures such as corners and connections, as well as the information of tilted graphics, etc. Therefore, the contour information of the entire graphic (i.e., multiple contour points of the graphic) can be extracted through the scanning electron microscope (SEM) image, and modeling can be carried out based on this contour information, thereby making up for the missing information of the complex environment.

[0063] By extracting contour points from SEM images, a large amount of position data can be obtained in a relatively short period of time. This provides convenience while also bringing new challenges. If too much data is input into the modeling process for calculation, the efficiency and speed of modeling will be drastically reduced, thereby delaying the completion of the model. Therefore, it is necessary to solve how to downsample a large amount of position data, and minimize the redundancy of the data while ensuring that sufficient two-dimensional graphic position information can be provided. In addition, due to image noise and other reasons, the contour extraction algorithm will have some abnormal points that are not smooth. How to remove the abnormal points is also very important.

[0064] In order to solve the problems of the traditional solution, the embodiment of the present application provides a contour point processing method, device, medium and product. The contour point processing method provided by the embodiment of the present application is first introduced below. Figure 1 FIG. 1 is a flow chart of a contour point processing method provided by an embodiment of the present application. Figure 1 As shown, the method includes the following steps: S101 to S103.

[0065] S101: extracting contour points of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence.

[0066] The present application does not limit the specific implementation method of extracting contour points. As a feasible implementation method, multiple initial points can be established, and then based on the contour of the photoresist pattern, each initial point is moved, that is, these initial points are moved closer to the contour of the photoresist pattern, thereby obtaining multiple contour points, and these contour points are arranged in a point sequence in the order of the graphic contour, that is, a first point sequence is obtained.

[0067] Usually, the first point sequence includes a large number of contour points; therefore, downsampling is required, that is, filtering out some redundant points. In addition, during contour extraction, due to image noise and other reasons, some abnormal points that are not smooth will appear. In order to ensure the accuracy of the data, the abnormal points need to be filtered out.

[0068] Since the position of the outliers in the entire first point sequence is relatively special, the presence of outliers will cause this algorithm to misjudge the type of some contour points. That is, determining redundant points when there are outliers in the first point sequence will lead to wrong results. Therefore, it is usually possible to first determine the outliers and filter them out, and then filter out the redundant points after filtering out the outliers. The following is a specific explanation.

[0069] S102: Filter out abnormal points in the first point sequence to obtain a second point sequence.

[0070] The abnormal point is a contour point that meets the first preset condition; the first preset condition includes that there is only one first intermediate point between the first point pair in the first point sequence, and the first distance corresponding to the first intermediate point is greater than the first threshold; the first point pair is determined from the first point sequence based on the first threshold using the Douglas-Peucker algorithm; the first distance is the distance from the first intermediate point to the first straight line, and the first straight line is the straight line where the first point pair is located.

[0071] It should be noted that the present application does not simply use the Douglas-Peucker algorithm, but determines the point pairs based on the idea of ​​this algorithm, and then determines the abnormal points and redundant points. The idea of ​​the Douglas-Peucker algorithm adopted in the present application is roughly as follows: Assuming that there is a point sequence to be processed, first select the starting point and the ending point in the point sequence as the first point pair. Then, among the points in the point sequence between the point pairs, find the point farthest from the straight line where the point pair is located. If the distance from the farthest point to the straight line where the point pair is located is greater than the set threshold (i.e., the first threshold and the second threshold), the farthest point is respectively combined with the two points in the point pair to form two new point pairs, and then the above steps are repeated until the iteration stops.

[0072] Based on the content of the Douglas-Peucker algorithm, after setting the first threshold, the Douglas-Peucker algorithm can be used to determine multiple first point pairs in the first point sequence, and multiple first straight lines can be obtained by connecting the first point pairs. Based on each first point pair and the first straight line, an abnormal point that meets the first preset condition can be determined from the first point sequence.

[0073] Specifically, as mentioned above, the first preset condition includes that there is only one first intermediate point between the first point pair in the first point sequence, and the first distance corresponding to the first intermediate point is greater than the first threshold, and the first distance is the distance from the first intermediate point to the first straight line. This is because when there is only one first intermediate point between the first point pair in the first point sequence, the two contour points of the first point pair and the first intermediate point are three adjacent contour points. If the first distance is too large at this time, it indicates that there is a large difference in position between the first intermediate point and the remaining contour points, and it can be determined to be abnormal.

[0074] As an optional implementation for determining an outlier, the first point sequence may be iteratively processed by the Douglas-Peucker algorithm to obtain a plurality of first point pairs, and then a first point pair having only one first intermediate point is found (i.e., the first point sequence has only one contour point between such first point pairs). Then, a first distance between the first intermediate point and the first straight line where the corresponding first point pair is located is determined, and when the first distance is greater than a first threshold, the corresponding first intermediate point is determined as an outlier.

[0075] It should be noted that when determining outliers, some normal contour points may be misjudged as outliers. However, since the amount of data in the first point sequence is large enough and redundant outliers will be filtered out later, filtering out the misjudged outliers at this time will not affect the final result.

[0076] S103: Filter out redundant points in the second point sequence to obtain a third point sequence.

[0077] If too much data is input into the modeling process for calculation, the efficiency and speed of modeling will be drastically reduced, thus delaying the completion of the model. Therefore, it is necessary to filter out the redundant points determined in the second point sequence to obtain the final third point sequence, so as to perform photoresist modeling based on the third point sequence.

[0078] The redundant points are contour points in the second point sequence that are located between the second point pairs that meet the second preset condition; the second preset condition includes that the distance from each second intermediate point to the second straight line is less than the second threshold; the second intermediate points include contour points in the second point sequence that are located between the second point pairs; the second point pairs are determined from the second point sequence using the Douglas-Peucker algorithm based on the second threshold; the second straight line is the straight line where the second point pair is located.

[0079] Similarly, based on the content of the Douglas-Peucker algorithm, after setting the second threshold, the Douglas-Peucker algorithm can be used to determine multiple second point pairs in the second point sequence, and multiple second straight lines can be obtained by connecting the second point pairs. Based on each second point pair and the second straight line, an abnormal point that meets the second preset condition can be determined from the second point sequence.

[0080] Specifically, as mentioned above, the second preset condition includes that the distance from each second intermediate point to the second straight line is less than the second threshold value. The second intermediate points include contour points of the second point sequence located between the second point pairs. That is, the position difference between the second intermediate points and the second point pairs is not large, and the two contour points based on the second point pairs can represent this segment of the graph, and the corresponding second intermediate points are all redundant data.

[0081] As an optional implementation method for determining redundant points, the second point sequence may be iteratively processed by the Douglas-Peucker algorithm to obtain a plurality of second point pairs. For each second point pair, the distance from each contour point (second intermediate point) of the second point sequence located between the second point pair to the corresponding second straight line is determined, and when the distance from each second intermediate point to the second straight line is less than the second threshold, the second intermediate points are determined as redundant points.

[0082] As an optional implementation, in the process of determining redundant points, the farthest point from the second straight line among the second intermediate points can be directly determined. When the distance between the farthest point and the second straight line is not greater than the second threshold, it indicates that the distance between each second intermediate point and the second straight line is not greater than the second threshold.

[0083] In practical applications, the actual values ​​of the first threshold and the second threshold are not limited and can be set according to actual conditions. Because the contour point processing method provided in the embodiment of the present application includes two parts, filtering out abnormal points and filtering out redundant points, and the two parts have different purposes, the distance thresholds used are also different. When filtering out abnormal points, the first threshold is used; when filtering out redundant points, the second threshold is used. As an optional implementation, the threshold of the first threshold is greater than the second threshold to ensure that the determination of abnormal points and redundant points is more accurate.

[0084] In addition, after filtering out the abnormal points and redundant points to obtain the third point sequence, photolithography modeling can be performed based on the third point sequence. The traditional solution uses CD for modeling, ignoring the more complex two-dimensional structures such as corners and connections, as well as information on tilted graphics, etc. Therefore, as an optional implementation, in the modeling process, the CD information and the third point sequence obtained after the above steps can be mixed and inputted, and the two can be used simultaneously as modeling inputs, thereby building a more accurate and predictive photoresist model.

[0085] A method for processing contour points provided in an embodiment of the present application first extracts a first point sequence of a photoresist pattern, then filters out abnormal points in the first point sequence to obtain a second point sequence; finally, filters out redundant points in the second point sequence to obtain a third point sequence. In this implementation, the first point sequence is filtered in two steps. In the first step, abnormal contour points are filtered out by a first threshold value, thereby ensuring the accuracy of the remaining contour points, and thus a more accurate lithography model can be obtained. In the second step, redundant contour points are filtered out by a second threshold value, thereby reducing the amount of data and ensuring the modeling speed. This solution specifically utilizes the positional relationship between the first point pair and the second point pair and each intermediate point to filter out abnormal points and redundant points, which not only reduces the amount of data, but also ensures the accuracy of the data, thereby improving the speed and accuracy of modeling.

[0086] The embodiment of the present application provides a specific implementation scheme of the Douglas-Peucker algorithm. Figure 2 FIG. 2 shows a schematic diagram of the process of the Douglas-Peucker algorithm provided by an embodiment of the present application. Figure 2 As shown, the algorithm specifically includes the following steps: S201 to S204.

[0087] S201: Acquire the starting point and the ending point of the input contour point sequence to obtain contour point pairs.

[0088] The input contour point sequence may include the first point sequence or the second point sequence mentioned above, and the contour point pair may include the first point pair or the second point pair.

[0089] For different types of photoresist patterns, the definitions of the starting point and the ending point may be different. As some optional implementations, for a non-closed photoresist pattern, the starting point and the ending point are fixed, i.e., the two ends of the pattern. For a closed photoresist pattern, the starting point and the ending point are not fixed, and any two adjacent points can be used as the starting point and the ending point of the closed photoresist pattern, respectively.

[0090] S202: among the contour points in the contour point sequence located between the contour point pairs, obtaining the point farthest from the straight line where the contour point pair is located.

[0091] Connect the two contour points of the contour point pair to obtain a straight line. Then, among the contour points in the contour point sequence between the contour point pair, obtain the contour point farthest from the straight line, that is, the farthest point.

[0092] Normally, among the contour points between the contour point pair, there is usually only one contour point that is farthest from the straight line where the contour point pair is located. In this case, it can be directly determined as the farthest point. However, in special cases, there may be multiple contour points farthest from the straight line where the contour point pair is located. As a feasible implementation method, one of the contour points can be randomly selected as the farthest point.

[0093] S203: Obtain the distance from the farthest point to the straight line where the contour point pair is located, and determine whether the distance is greater than a distance threshold; if the distance is greater than the distance threshold, trigger S204.

[0094] S204: The farthest point is combined with two contour points of the contour point pair to form two new contour point pairs; and the process returns to S202; until the contour point sequence is located between the contour point pairs and there is no contour point whose distance to the straight line where the contour point pair is located is greater than the distance threshold.

[0095] The distance from the farthest point to the straight line where the contour point pair is located is the length of the perpendicular segment from the farthest point to the straight line. It can be calculated using the commonly used formula for calculating the distance from a point to a straight line.

[0096] At this point, multiple sets of corresponding contour point pairs, the straight lines on which the contour point pairs are located, the farthest points, and the distances between the points and the straight lines are obtained; then, based on different situations, abnormal points or redundant points are determined according to this information.

[0097] A specific embodiment is provided here, which performs iterative operations on a specific contour point sequence based on the Douglas-Peucker algorithm. Figure 3 FIG. 1 is a schematic diagram showing the first iteration of the Douglas-Peucker algorithm provided by an embodiment of the present application on a specific contour point sequence. Figure 3 As shown, this contour point sequence specifically includes P1 to P10. The figure corresponding to this contour point sequence is a non-closed figure, with the contour points P1 and P10 at both ends as the starting point and the end point of the figure, that is, the first group of contour point pairs. Connect the contour points P1 and P10, and the resulting dotted line is the straight line (P1-P10). Among the contour points (P1 to P9) between the two contour points P1 and P10 of the contour point pair, obtain the contour point farthest from the straight line (P1-P10) to obtain the farthest point P7. Obtain the distance from the farthest point P7 to the straight line (P1-P10). Assuming that this distance is greater than the preset distance threshold, enter the next iteration.

[0098] Figure 4 FIG. 1 is a schematic diagram showing a second iteration of a specific contour point sequence using the Douglas-Peucker algorithm provided by an embodiment of the present application. Figure 4 As shown in the figure, assuming that the distance from the farthest point P7 to the straight line where the contour point pair is located is greater than the distance threshold, the farthest point P7 is combined with the two contour points P1 and P10 of the contour point pair to form two new contour point pairs, namely P1 and P7, and P10 and P7. Then, the above process is executed for the two new contour point pairs to obtain the new farthest points P4 and P8.

[0099] The farthest point corresponding to the contour point pair P1 and P7 is P4. The distance from the farthest point P4 to the straight line (P1-P7) where the contour point pair is located is obtained. If this distance is greater than the distance threshold, the next iteration is entered.

[0100] The farthest point corresponding to the contour point pair P10 and P7 is P8. The distance from the farthest point P8 to the straight line (P10-P7) is obtained. If this distance is not greater than the preset distance threshold, the iteration of this branch stops.

[0101] Figure 5 FIG. 1 is a schematic diagram showing the third iteration of the Douglas-Peucker algorithm provided by an embodiment of the present application on a specific contour point sequence. Figure 5As shown in the figure, assuming that the distance between the farthest point P4 and the straight line (P1-P7) is greater than the distance threshold, the farthest point P4 is combined with the two contour points P1 and P7 of the contour point pair to form two new contour point pairs, namely P1 and P4, and P7 and P4. Then, the above process is executed for the two new contour point pairs to obtain the new farthest points P2 and P6.

[0102] The farthest point corresponding to the contour point pair P1 and P4 is P2. Get the distance from the farthest point P2 to the straight line (P1-P4). If this distance is not greater than the distance threshold, the iteration of this branch stops.

[0103] The farthest point corresponding to the contour point pair P7 and P4 is P6. Get the distance from the farthest point P6 to the straight line (P7-P4). If this distance is not greater than the distance threshold, the iteration of this branch stops.

[0104] At this point, the iteration of the Douglas-Peucker algorithm on the entire contour point sequence (P1 to P10) ends. For each contour point pair, there is no contour point between the two contour points whose distance to the straight line where the contour point pair is located is greater than the distance threshold.

[0105] Figure 6 FIG. 4 is a schematic diagram showing the fourth iteration of the Douglas-Peucker algorithm provided by an embodiment of the present application on a specific contour point sequence. Figure 6 As shown in the figure, it is assumed that it is necessary to filter out the redundant points in the contour point sequence, that is, when the distance between each intermediate point and the straight line where the contour point pair is located is not greater than the distance threshold, the corresponding intermediate points are determined as redundant points and filtered out. The remaining contour points are P1, P4, P7 and P10.

[0106] As mentioned above, the outliers in the first point sequence can be determined based on the Douglas-Peucker algorithm. The specific determination process can be set according to the actual situation. As an optional implementation, the outlier determination process specifically includes:

[0107] First, the starting point and the ending point in the first point sequence are obtained as the first point pair. For closed figures and non-closed figures, the first set of first point pairs can be determined in different ways. Then, the maximum distance between each contour point between the first point pair in the first point sequence and the first straight line is obtained as the first distance.

[0108] Furthermore, when the first distance is greater than the first threshold, the contour points corresponding to the first distance are respectively combined with the two contour points of the first point pair to form two new first point pairs; and the maximum distance between each contour point between the first point pair in the first point sequence and the first straight line is obtained as the first distance step; until there is no contour point whose distance to the first straight line is greater than the first threshold among the contour points between the first point pair in the first point sequence.

[0109] Finally, the contour points that meet the first preset condition are determined as abnormal points; and the second point sequence can be obtained by filtering out the abnormal points in the first point sequence.

[0110] The embodiment of the present application provides a specific implementation method for filtering outliers, inputting a first point sequence into the Douglas-Peucker algorithm, and obtaining multiple groups of corresponding first point pairs, first straight lines, first distances and other information through continuous iteration.

[0111] In the method for determining abnormal points provided by the present implementation, when there is only one first intermediate point between the first point pair, the corresponding first point pair and the first intermediate point are three adjacent contour points, and the positional relationship of the three points can be determined by the corresponding first distance. When the first distance is too large, it indicates that the first intermediate point is likely to be an abnormal contour point, and filtering it out can ensure the data accuracy of the contour point sequence.

[0112] After filtering out the abnormal points in the first point sequence, a second point sequence is obtained, and the redundant points in the second point sequence need to be determined based on the Douglas-Peucker algorithm. The specific determination process can be set according to the actual situation. As an optional implementation, the redundant point determination process specifically includes:

[0113] First, the starting point and the ending point in the second point sequence are obtained as the second point pair. Similarly, for closed figures and non-closed figures, the first set of second point pairs can be determined in different ways. It should be noted that the first set of second point pairs determined here can be the same as the first set of first point pairs determined. Then, the maximum distance between each contour point located between the second point pairs in the second point sequence and the second straight line is obtained as the second distance.

[0114] Furthermore, when the second distance is greater than the second threshold, the contour points corresponding to the second distance are respectively combined with the two contour points of the second point pair to form two new second point pairs; and the maximum distance between each contour point located between the second point pair in the second point sequence and the second straight line is obtained as the step of the second distance; until there is no contour point whose distance to the second straight line is greater than the second threshold among the contour points located between the second point pair in the second point sequence.

[0115] Finally, each contour point between the second point pairs satisfying the second preset condition in the second point sequence is determined as a redundant point; the redundant points in the second point sequence are filtered out to obtain the third point sequence.

[0116] Here, a specific implementation method for filtering out redundant points is provided. The second point sequence is input into the Douglas-Peucker algorithm, and through continuous iteration, multiple groups of corresponding second point pairs, second straight lines, second distances and other information are obtained.

[0117] In the method for determining redundant points provided by the present implementation, when the distance from each second intermediate point to the second straight line is not greater than the second threshold, the two contour points of the second point pair can represent this segment of the graphic, and the corresponding second intermediate points can be considered as redundant points. Therefore, these contour points can be filtered out to reduce the data volume of the contour point sequence, thereby improving the modeling efficiency.

[0118] The present application does not limit how to extract contour points. As an optional implementation, multiple initial points can be established first, and then the initial points can be moved based on the contour of the photoresist pattern in the SEM image to obtain a first point sequence.

[0119] Figure 7 A schematic diagram of a method for extracting contour points of a first photoresist pattern provided by an embodiment of the present application is shown. Figure 7 As shown in the figure, the points on the outer square box are the initial points, and the inner side is the normal photoresist pattern. When extracting the contour points, the initial points are moved according to the signal direction of the SEM image, that is, these initial points are moved to the contour of the photoresist pattern, and finally the contour points on the inner photoresist pattern are obtained. Finally, based on the order of the contour of the photoresist pattern, the first point sequence is obtained.

[0120] Figure 8 FIG. 1 is a schematic diagram showing a method for extracting the contour points of a second photoresist pattern provided by an embodiment of the present application. Figure 8 As shown, the point on the outer square box is the initial point, and the inner side is an abnormal photoresist pattern. The initial point is moved in the same way as above. Since the outline of the pattern is abnormal, there are abnormal points in the first point sequence finally obtained.

[0121] The embodiment of the present application proposes a contour point extraction solution, which can efficiently extract the contour points of the photoresist pattern based on the SEM image.

[0122] In practical applications, both the first threshold and the second threshold can be set based on demand. A suitable first threshold can more accurately determine the outliers and avoid misjudging some useful contour points as outliers.

[0123] As an optional implementation, after moving each initial point based on the outline of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence, the moving distance of each initial point toward the outline of the photoresist pattern is determined; and then the first threshold is determined based on the moving distance.

[0124] The moving distance of the abnormal point is usually significantly different from the moving distance of the surrounding normal contour points, so the first threshold can be determined based on the moving distance. As an optional implementation, the moving distances of all points in the entire SEM image can be evaluated and fitted with a Gaussian distribution, and the sigma value of this Gaussian function can be used to determine the first threshold.

[0125] In this implementation, the first threshold is adaptively adjusted through the displacement distance of each contour point during the extraction process to ensure the accuracy of screening; not only can the outliers be determined more accurately, but also some useful contour points can be avoided from being misjudged as outliers.

[0126] Furthermore, a suitable second threshold can avoid filtering out useful contour points while achieving downsampling as much as possible.

[0127] As an optional implementation, after moving each initial point based on the contour of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence, the curvature of each contour point can be determined based on the adjacent contour points of the contour point; finally, the second threshold is determined based on each curvature.

[0128] As an optional implementation, the vector value can be calculated by two adjacent contour points of each contour point, so as to calculate the curvature of the current contour point. Assume that the current point is P2, and the previous and next points are P1 and P3:

[0129] cost(θ)=(v 12 *v 23 ) / (|v 12 |*|v 23 |) (1)

[0130]

[0131] Among them, cost(θ) is, v 12 is the vector from P1 to P2, v 23 is the vector from P2 to P3, d 12 is the distance from P1 to P2, d 23 is the distance from P2 to P3, θ is v 12 With v 23 , κ is the curvature corresponding to point P2.

[0132] The curvatures of all contour points may be traversed and calculated, wherein the minimum curvature among all contour points may be used to determine the second threshold.

[0133] In this implementation, the second threshold is adaptively adjusted according to the curvature of the photoresist pattern to ensure the accuracy of screening; not only useless redundant points can be filtered out as much as possible, but also useful contour points can be avoided from being filtered out.

[0134] As mentioned above, for closed graphics and non-closed graphics, the first set of contour point pairs can be determined in different ways. For a closed photoresist graphic, as an optional implementation, the starting point and the ending point in the first point sequence are obtained as the first point pair, including:

[0135] In the first point sequence, any two adjacent contour points on the photoresist pattern are selected as the starting point and the ending point of the first point sequence;

[0136] or,

[0137] Get the starting point and ending point in the second point sequence as the second point pair, including:

[0138] In the second point sequence, any two adjacent contour points on the photoresist pattern are selected as the starting point and the ending point of the second point sequence.

[0139] This is because all points of the closed photoresist pattern are continuous, and any two adjacent contour points as the starting point and the ending point of the photoresist pattern can include all the remaining contour points between the first group of contour point pairs.

[0140] In this implementation, for a closed photoresist pattern, any two adjacent contour points can be used as the starting point and the ending point of the photoresist pattern. In practical applications, more possibilities for selecting contour point pairs can be provided, thereby improving the accuracy of data screening.

[0141] For a non-closed photoresist pattern, as an optional implementation, a starting point and an ending point in a first point sequence are obtained as a first point pair, including:

[0142] Selecting two contour points at both ends of the photoresist pattern in the first point sequence as the starting point and the ending point of the second point sequence;

[0143] or,

[0144] Get the starting point and ending point in the second point sequence as the second point pair, including:

[0145] In the second point sequence, two contour points at both ends of the photoresist pattern are selected as the starting point and the ending point of the second point sequence.

[0146] Because the non-closed photoresist pattern has two endpoints, only by taking the contour points corresponding to the two endpoints as the starting point and the ending point of the photoresist pattern can all the remaining contour points be included between the first group of contour point pairs.

[0147] In this implementation, for a non-closed photoresist pattern, only two contour points at both ends of the photoresist pattern can be used as the starting point and the ending point of the photoresist pattern, thereby ensuring that no contour points are missed and ensuring the effect of data screening.

[0148] Fig. 9 FIG. 1 is a schematic diagram showing the hardware structure of the contour point processing device provided in the embodiment of the present application. Fig. 9 As shown, the contour point processing device may include a processor 901 and a memory 902 storing computer program instructions.

[0149] Specifically, the processor 901 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0150] The memory 902 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 902 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In appropriate cases, the memory 902 may include a removable or non-removable (or fixed) medium. In appropriate cases, the memory 902 may be inside or outside the integrated gateway disaster recovery device. In a specific embodiment, the memory 902 is a non-volatile solid-state memory.

[0151] The memory 902 may include a read-only memory (ROM), a random access memory (RAM), a magnetic disk storage medium device, an optical storage medium device, a flash memory device, an electrical, optical or other physical / tangible memory storage device. Therefore, generally, the memory includes one or more tangible (non-transitory) computer-readable storage media (e.g., a memory device) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processors), it is operable to perform the operations described with reference to the method according to one aspect of the present disclosure.

[0152] The processor 901 implements any one of the contour point processing methods in the above embodiments by reading and executing computer program instructions stored in the memory 902 .

[0153] In one example, the contour point processing device may further include a communication interface 903 and a bus 904. The processor 901, the memory 902, and the communication interface 903 are connected via the bus 904 and communicate with each other.

[0154] The communication interface 903 is mainly used to implement communication between various modules, devices, units and / or equipment in the embodiments of the present application.

[0155] Bus 904 comprises hardware, software or both, and the parts of outline point processing equipment are coupled to each other.For example, but not limitation, bus may comprise accelerated graphics port (Accelerate Graphical Port, AGP) or other graphics bus, enhanced industry standard architecture (Enhanced Industry Standard Architecture, EISA) bus, front side bus (Front Side Bus, FSB), hypertransmission (Hyper Transport, HT) interconnection, industry standard architecture (IndustryStandard Architecture, ISA) bus, infinite bandwidth interconnection, low pin count (Low Pin Count, LPC) bus, memory bus, micro channel architecture (Micro Channel Architecture, MCA) bus, peripheral component interconnection (Peripheral Component Interconnect, PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (Serial Advanced Technology Attachment, SATA) bus, video electronics standard association local (Video Electronics Standards Association Local Bus, VLB) bus or other suitable bus or two or more of these combinations.In suitable cases, bus 904 may comprise one or more buses. Although embodiments of the present application describe and illustrate a particular bus, the present application contemplates any suitable bus or interconnect.

[0156] In addition, in combination with the contour point processing method in the above embodiment, the embodiment of the present application can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any contour point processing method in the above embodiment is implemented.

[0157] An embodiment of the present application also provides a computer program product, including a computer program, which implements any one of the contour point processing methods in the above embodiments when the computer program is processed and executed.

[0158] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0159] The functional blocks shown in the block diagram above can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an ASIC, appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (Erasable ROM, EROM), floppy disks, compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM), optical discs, hard disks, optical fiber media, radio frequency (Radio Frequency, RF) links, etc. Code segments can be downloaded via computer networks such as the Internet, intranets, etc.

[0160] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0161] The above reference is to a flow chart and / or block diagram of a contour point processing method, device, medium and product according to an embodiment of the present disclosure, and describes various aspects of the present disclosure. It should be understood that each box in the flow chart and / or block diagram and the combination of each box in the flow chart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flow chart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flow chart and the combination of boxes in the block diagram and / or flow chart can also be implemented by special-purpose hardware that performs a specified function or action, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0162] The above contents are only specific implementation methods of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application.

Claims

1. A contour point processing method, characterized in that: include: Extracting the contour points of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence; Filter out abnormal points in the first point sequence to obtain a second point sequence; The abnormal point is a contour point that satisfies a first preset condition; the first preset condition includes that there is only one first intermediate point between the first point pair in the first point sequence, and the first distance corresponding to the first intermediate point is greater than a first threshold; The first point pair is determined from the first point sequence based on the first threshold by using the Douglas-Peucker algorithm; the first distance is the distance from the first intermediate point to a first straight line, and the first straight line is the straight line where the first point pair is located; Redundant points in the second point sequence are filtered out to obtain a third point sequence; the redundant points are contour points in the second point sequence that are located between second point pairs that meet a second preset condition; the second preset condition includes that the distance from each second intermediate point to the second straight line is less than a second threshold; the second intermediate points include contour points in the second point sequence that are located between second point pairs; the second point pairs are determined from the second point sequence using the Douglas-Peucker algorithm based on the second threshold; the second straight line is the straight line where the second point pair is located.

2. The contour point processing method according to claim 1, characterized in that: The filtering out the abnormal points in the first point sequence to obtain the second point sequence includes: Acquire a starting point and an ending point in the first point sequence as the first point pair; Acquire the maximum distance between each contour point located between the first point pair in the first point sequence and the first straight line as a first distance; In the case where the first distance is greater than the first threshold, the contour point corresponding to the first distance is respectively combined with the two contour points of the first point pair to form two new first point pairs; and the maximum distance between each contour point between the first point pair in the first point sequence and the first straight line is obtained as the first distance; until there is no contour point whose distance from the first straight line is greater than the first threshold among the contour points between the first point pair in the first point sequence; Determine the contour points that meet the first preset condition as the abnormal points; The abnormal points in the first point sequence are filtered out to obtain the second point sequence.

3. The contour point processing method according to claim 1, characterized in that: The filtering out redundant points in the second point sequence to obtain a third point sequence includes: Obtaining a starting point and an ending point in the second point sequence as the second point pair; Acquire the maximum distance between each contour point located between the second point pair in the second point sequence and the second straight line as the second distance; In the case where the second distance is greater than the second threshold, the contour point corresponding to the second distance is respectively combined with the two contour points of the second point pair to form two new second point pairs; and the maximum distance between each contour point between the second point pair in the second point sequence and the second straight line is returned to the step of obtaining the maximum distance between each contour point between the second point pair in the second point sequence and the second straight line as the second distance; until there is no contour point whose distance to the second straight line is greater than the second threshold among each contour point between the second point pair in the second point sequence; Determine each contour point located between the second point pairs satisfying the second preset condition in the second point sequence as the redundant point; The redundant points in the second point sequence are filtered out to obtain the third point sequence.

4. The contour point processing method according to any one of claims 1 to 3, characterized in that: The step of extracting the contour points of the photoresist pattern in the scanning electron microscope image to obtain a first point sequence includes: Establish multiple initial points; Based on the outline of the photoresist pattern in the scanning electron microscope image, each of the initial points is moved to obtain the first point sequence.

5. The contour point processing method according to claim 4, characterized in that: After moving each of the initial points based on the profile of the photoresist pattern in the scanning electron microscope image to obtain the first point sequence, the method further includes: Determining the moving distance of each of the initial points toward the outline of the photoresist pattern; The first threshold is determined based on the moving distance.

6. The contour point processing method according to claim 4, characterized in that: After moving each of the initial points based on the outline of the photoresist pattern in the scanning electron microscope image to obtain the first point sequence, the method further includes: For each of the contour points, determining the curvature of each contour point based on the adjacent contour points of the contour point; Based on each of the curvatures, the second threshold is determined.

7. The contour point processing method according to claim 2 or 3, characterized in that: The photoresist pattern is a closed pattern; Acquiring a starting point and an ending point in the first point sequence as the first point pair includes: Selecting any two adjacent contour points on the photoresist pattern in the first point sequence as the starting point and the ending point of the first point sequence; or, Acquiring a starting point and an ending point in the second point sequence as the second point pair includes: Any two adjacent contour points on the photoresist pattern are selected in the second point sequence as the starting point and the ending point of the second point sequence.

8. The contour point processing method according to claim 2 or 3, characterized in that: The photoresist pattern is a non-closed pattern; Acquiring a starting point and an ending point in the first point sequence as the first point pair includes: Selecting two contour points at both ends of the photoresist pattern in the first point sequence as the starting point and the ending point of the second point sequence; or, Acquiring a starting point and an ending point in the second point sequence as the second point pair includes: Two contour points at both ends of the photoresist pattern are selected in the second point sequence to serve as the starting point and the ending point of the second point sequence.

9. A contour point processing device, characterized in that: include: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the contour point processing method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions, and when the computer program instructions are executed by a processor, the contour point processing method according to any one of claims 1 to 8 is implemented.

11. A computer program product, characterized in that When the instructions in the computer program product are executed by a processor of an electronic device, the electronic device executes the contour point processing method as described in any one of claims 1 to 8.

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