Method and apparatus for detecting wafer defects

Abstract

The present application relates to the semiconductor technical field and provides a method and apparatus for detecting wafer defects, the method including: determining repeating pattern units and non-repeating pattern units in the SEM image based on a target SEM image and pattern units in a design layout; measuring the pattern units, repeating pattern units, and non-repeating pattern units in the design layout to determine difference information; and determining whether the repeating pattern units and non-repeating pattern units have defects based on the difference information. In this way, by measuring the SEM image and the pattern units in the design layout, difference information that can represent the SEM image is obtained, and then defect detection is performed on the SEM image based on the difference information. Since the characteristics of the SEM image and the pattern units in the design layout are fully taken into account in the defect detection process, the determined difference information is more comprehensive and reliable, thereby improving the accuracy and reliability of subsequent wafer defect detection.

Description

[Technical Field]

[0001] This application relates to the field of semiconductor technology, and more particularly to a method and apparatus for detecting wafer defects. [Background technology]

[0002] With the development of the semiconductor industry, the application of integrated circuits is becoming more and more widespread. The manufacturing process of integrated circuits involves many processes, and each process may cause wafer contamination, so wafer defect detection is essential during the wafer manufacturing process.

[0003] In related art, when defect detection is performed on a wafer, a certain threshold is usually set, and if the difference between the target wafer and a reference wafer exceeds the threshold, it is determined that the wafer has a defect. However, because the threshold is a fixed value, if the target image is complex, detection omissions or false detections may occur, which may affect the accuracy of wafer defect detection. Therefore, how to improve the accuracy of wafer defect detection is extremely important. Summary of the Invention

[0004] The present application provides a method and apparatus for detecting wafer defects.

[0005] According to a first aspect of the present application, there is provided a method for detecting wafer defects, including: determining repeating pattern units and non-repeating pattern units in an SEM image based on an SEM image to be detected and pattern units in a design layout; measuring the pattern units, the repeating pattern units, and the non-repeating pattern units in the design layout to determine difference information; and determining whether there are defects in the repeating pattern units and the non-repeating pattern units based on the difference information.

[0006] In some embodiments, determining repeating and non-repeating pattern units in the SEM image based on the pattern units in the SEM image and the design layout to be detected includes processing the SEM image to obtain pattern contours in the SEM image, and matching the pattern contours with pattern units in the design layout to determine repeating and non-repeating pattern units in the SEM image.

[0007] In some embodiments, measuring a pattern unit, the repeating pattern unit, and the non-repeating pattern unit in the design layout to determine difference information includes dividing the non-repeating pattern unit to obtain a repeating sub-pattern unit and an isolated sub-pattern unit; setting measurement points on the repeating pattern unit and the repeating sub-pattern unit to determine first measurement data; setting measurement points at the same positions of corresponding target pattern units in the design layout to determine second measurement data; and determining difference information based on the first measurement data and the second measurement data.

[0008] In some embodiments, determining difference information based on the first measurement data and the second measurement data includes determining difference information corresponding to each measurement type based on a measurement type of the first measurement data and a measurement type of the second measurement data, respectively.

[0009] In some embodiments, determining whether the repeating pattern unit and non-repeating pattern unit are defective based on the difference information includes: determining a mean value and a standard deviation corresponding to a measurement type based on a measurement type of first measurement data and second measurement data corresponding to the difference information; and determining whether the repeating pattern unit or repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, the corresponding mean value and the standard deviation.

[0010] In some embodiments, determining whether the repeating pattern unit or repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type and the corresponding mean value and standard deviation includes: determining a measurement threshold corresponding to the measurement type based on the mean value and standard deviation corresponding to the measurement type; if any of the first measurement data is greater than the measurement threshold for the measurement type, determining that the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located is defective; determining the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located as an abnormal pattern unit, and storing the abnormal pattern unit and any of the first measurement data in an abnormal feature library.

[0011] In some embodiments, determining whether the repeating pattern unit and the non-repeating pattern unit are defective based on the difference information includes matching the isolated sub-pattern unit with an abnormal pattern unit in an abnormal feature library to determine a degree of match, and determining whether the isolated sub-pattern unit is defective based on the degree of match.

[0012] According to a second aspect of the present application, there is provided an apparatus for detecting wafer defects, including: a first determination module for determining repeating pattern units and non-repeating pattern units in an SEM image based on an SEM image to be detected and pattern units in a design layout; a measurement module for measuring the pattern units, the repeating pattern units, and the non-repeating pattern units in the design layout to determine difference information; and a second determination module for determining whether there are defects in the repeating pattern units and non-repeating pattern units based on the difference information.

[0013] In some embodiments, the first determination module is specifically used to process the SEM image to obtain pattern contours in the SEM image, and match the pattern contours with pattern units in the design layout to determine repeating and non-repeating pattern units in the SEM image.

[0014] In some embodiments, the measurement module includes a division submodule for dividing the non-repeating pattern unit to obtain a repeating sub-pattern unit and an isolated sub-pattern unit, a first determination submodule for setting measurement points in the repeating pattern unit and the repeating sub-pattern unit to determine first measurement data, a second determination submodule for setting measurement points at the same positions of a target pattern unit corresponding to the design layout to determine second measurement data, and a third determination submodule for determining difference information based on the first measurement data and the second measurement data.

[0015] In some embodiments, the third determination sub-module is used to determine difference information corresponding to each measurement type based on a measurement type of the first measurement data and a measurement type of the second measurement data.

[0016] In some embodiments, the second determination module includes a fourth determination sub-module for determining a mean value and a standard deviation corresponding to a measurement type based on the measurement type of first measurement data and second measurement data corresponding to the difference information, and a fifth determination sub-module for determining whether the repeating pattern unit or repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, the corresponding mean value and the standard deviation.

[0017] In some embodiments, the fifth determination submodule includes a first determination unit for determining a measurement threshold corresponding to the measurement type based on a mean value and standard deviation corresponding to the measurement type; a second determination unit for determining that the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located is defective if any of the first measurement data is greater than the measurement threshold of the measurement type; and a third determination unit for determining the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located as an abnormal pattern unit, and storing the abnormal pattern unit and any of the first measurement data in an abnormality feature library.

[0018] In some embodiments, the second determination module is specifically used to match the isolated sub-pattern unit with an abnormal pattern unit in an abnormal feature library to determine a degree of match, and to determine whether the isolated sub-pattern unit is defective based on the degree of match.

[0019] According to a third aspect of the present application, there is provided an electronic device including a processor and a memory in which computer program instructions are stored, wherein, when the processor executes the computer program instructions, any of the above methods for detecting wafer defects is realized.

[0020] According to a fourth aspect of the present application, there is provided a computer-readable storage medium having stored thereon computer program instructions that, when executed by a processor, realize any of the above methods for detecting wafer defects.

[0021] As described above, the method and apparatus for detecting wafer defects according to the present application achieve at least the following beneficial effects: first, based on the SEM image and the pattern units in the design layout to be detected, repeating pattern units and non-repeating pattern units in the SEM image are determined; then, the pattern units, repeating pattern units, and non-repeating pattern units in the design layout are measured to determine difference information; and, based on the difference information, it is possible to determine whether the repeating pattern units and non-repeating pattern units have defects. Thus, in the process of detecting wafer defects, the pattern units in the SEM image and the design layout are measured to obtain possible difference information representing the SEM image; and then, defect detection can be performed on the SEM image based on the difference information. Because the characteristics of the pattern units in the SEM image and the design layout are fully taken into account in the defect detection process, the determined difference information is more comprehensive and reliable, thereby improving the accuracy and reliability of subsequent wafer defect detection. [Brief explanation of the drawings]

[0022] The drawings described in this specification are intended to provide a further understanding of the present application and constitute a part of the present application. The illustrative examples and the description thereof are intended to aid in the interpretation of the present application and are not to be construed as undue limitations on the present application. The drawings are as follows: [Figure 1] 1 is a flowchart of a method for detecting wafer defects according to an embodiment of the present application. [Figure 2] 1A and 1B are schematic diagrams of a design layout and an SEM image to be detected according to an embodiment of the present application. [Figure 3] 1 is a flowchart of a method for detecting wafer defects according to an embodiment of the present application. [Figure 4] FIG. 2 is a schematic diagram of an SEM image, which is a detection target according to an embodiment of the present application, after division. [Figure 5] 1 is a structural diagram of an apparatus for detecting wafer defects according to an embodiment of the present application; [Figure 6]1 is a structural diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0023] In order to clarify the above and other features and advantages of the present application, the present application will be further described below with reference to the accompanying drawings. It should be understood that the specific examples provided in this specification are for the purpose of explaining to those skilled in the art and are merely illustrative and not limiting.

[0024] In the following description, numerous specific details are set forth to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that specific details are not required to practice the present application. In other instances, well-known steps or operations have not been described in detail so as not to obscure the present application.

[0025] The method for detecting wafer defects according to the embodiments of the present application can be performed by the apparatus for detecting wafer defects according to the embodiments of the present application, which may be equipped in an electronic device.

[0026] 1, the present application provides a method for detecting wafer defects, the method including the following steps:

[0027] In step 101, repeating pattern units and non-repeating pattern units in the SEM image are determined based on the SEM image to be detected and the pattern units in the design layout.

[0028] Here, a scanning electron microscope (SEM) image, also called a scanning electron microscope image, is an image collected by colliding a finely focused electron beam with the surface of a wafer and collecting secondary electrons, backscattered electrons, etc. generated by the interaction of the electrons with the wafer, and the SEM image can be used to detect and analyze defects on the wafer.

[0029] It can be understood that, in general, for a wafer to be inspected, an SEM image can be first acquired, and then a design layout corresponding to the wafer to be inspected can be acquired, and repeating and non-repeating pattern units in the SEM image can be determined by aligning and matching the SEM image with the pattern units in the corresponding design layout.

[0030] Here, when an SEM image of a wafer to be detected and a design layout are aligned, if a certain pattern unit 1 in the SEM image of the wafer to be detected matches multiple pattern units in the design layout, it can be determined that the pattern unit 1 is a repeating pattern unit. Alternatively, if a certain pattern unit 2 appears multiple times in the design layout, it can be determined that the pattern unit 3 in the SEM image matches pattern unit 2 that appears multiple times in the design layout. Alternatively, if a certain pattern unit 4 appears only once in the design layout, it can be determined that the pattern unit 5 corresponding to the pattern unit 4 in the SEM image is a non-repeating pattern unit.

[0031] It can be understood that the number of repeating pattern units in an SEM image can be one, multiple, or zero, and the number of non-repeating pattern units can be zero, one, multiple, etc., and this application is not limited thereto.

[0032] Optionally, the SEM image can be processed to obtain pattern contours in the SEM image, and then the pattern contours can be matched with pattern units in the design layout to determine repeating and non-repeating pattern units in the SEM image.

[0033] Here, the SEM image can be processed by any suitable method, such as image extraction, contour extraction, etc., to obtain pattern contours in the SEM image, and then each pattern contour in the SEM image can be aligned with each pattern unit in the design layout based on, for example, position coordinates, center points, etc., to perform matching, and then repeating pattern units and non-repeating pattern units in the SEM image can be determined based on the matching results.

[0034] For example, the pattern contour obtained by processing the SEM image is shown in Figure 2(a), the pattern units in the design layout are shown in Figure 2(b), and the two are aligned, and a schematic diagram after alignment is shown in Figure 2(c). Since pattern units 1', 2', 3', and 4' in the design layout are the same pattern that appears repeatedly, pattern units 1, 2, 3, and 4 in the corresponding SEM image are repeating pattern units, and since 5' in the design layout appears only once, 5 in the SEM image is a non-repeating pattern unit.

[0035] It should be noted that the above examples are merely illustrative and do not limit the shapes, numbers, positions, etc. of the repeating pattern units and non-repeating pattern units in the embodiments of the present application.

[0036] In step 102, pattern units, repeating pattern units, and non-repeating pattern units in the design layout are measured to determine difference information.

[0037] Here, the non-repeating pattern unit may be a complex pattern unit, and in the embodiments of the present application, the non-repeating pattern unit may be divided to obtain corresponding repeating sub-pattern units and isolated sub-pattern units, where the number of repeating sub-pattern units obtained by division may be one, multiple, or zero, and the number of isolated sub-pattern units may be one, zero, or multiple, but the present application is not limited thereto.

[0038] For example, if a non-repeating pattern unit is divided to obtain four identical rectangular patterns and one irregular pattern, the four identical rectangular patterns are repeating sub-pattern units, and the irregular pattern is an isolated sub-pattern unit.

[0039] It should be noted that the above examples are merely illustrative and do not limit the shapes, numbers, positions, etc. of the repeating sub-pattern units and isolated sub-pattern units in the embodiments of the present application.

[0040] Here, after determining the repeating pattern unit and the non-repeating pattern unit in the SEM image, the repeating pattern unit and the corresponding target pattern unit in the design layout are measured, and difference information corresponding to the repeating pattern unit can be determined based on the measurement results. Next, the non-repeating pattern unit can be divided to obtain repeating sub-pattern units and isolated sub-pattern units obtained by dividing the non-repeating pattern unit. The repeating sub-pattern unit and the target pattern unit in the design layout are measured, and difference information of the repeating sub-pattern unit can be determined based on the measurement results.

[0041] Furthermore, the difference information may be understood as the difference, ratio, etc. between the measurement results between a repeating pattern unit and a corresponding target pattern unit in the design layout, and the difference, ratio, etc. between the measurement results between a repeating sub-pattern unit and a corresponding target pattern unit in the design layout. The difference information may be used to represent the degree of difference between a repeating pattern unit and a target pattern unit in the design layout, and the degree of difference between a non-repeating pattern unit and a target pattern unit in the design layout, and the difference information may include one difference data or multiple difference data, etc., and the present application is not limited thereto.

[0042] In this way, in the embodiment of the present application, pattern units, repeating pattern units, and non-repeating pattern units in a design layout are measured, and difference information can be determined based on the measurement results. In the process of determining the difference information, the pattern units in the design layout and the pattern units in the SEM image are fully taken into consideration, so the difference information is more comprehensive and reliable and can better reflect the characteristics of the SEM image. This comprehensive and reliable difference information can be used for subsequent wafer defect detection.

[0043] In step 103, it is determined whether the repeating pattern units and the non-repeating pattern units are defective based on the difference information.

[0044] It can be understood that the difference information can be used to represent the degree of difference between the repeating pattern unit and the target pattern unit in the design layout, and the degree of difference between the non-repeating pattern unit and the target pattern unit in the design layout, so that the larger the difference information, the more likely the repeating pattern unit and the non-repeating pattern unit are defective, and the smaller the difference information, the less likely the repeating pattern unit and the non-repeating pattern unit are defective.

[0045] For example, if the difference value between a repeating pattern unit and the corresponding target pattern unit in the design layout is "0," the repeating pattern unit is considered to match the corresponding target pattern unit in the design layout and not have a defect. If the difference value between a repeating pattern unit and the corresponding target pattern unit in the design layout is "1," the repeating pattern unit is considered to not match the corresponding target pattern unit in the design layout and have a defect.

[0046] It should be noted that the above examples are merely illustrative and do not limit the methods for determining whether repeating pattern units and non-repeating pattern units have defects in the embodiments of the present application.

[0047] In this way, in the embodiment of the present application, the pattern units, repeating pattern units, and non-repeating pattern units in the design layout are measured to determine difference information, and based on the difference information, it can be determined whether there are defects in the repeating pattern units and non-repeating pattern units. In other words, in the process of determining the difference information, the SEM image and the pattern units in the design layout are fully taken into consideration, so that the determined difference information is more comprehensive and reliable and can better reflect the characteristics of the SEM image. Furthermore, when defect detection is performed on a wafer using the comprehensive and reliable difference information, the accuracy and reliability are increased.

[0048] In an embodiment of the present application, first, repeating pattern units and non-repeating pattern units in the SEM image are determined based on the SEM image to be detected and the pattern units in the design layout, then the pattern units, repeating pattern units, and non-repeating pattern units in the design layout are measured to determine difference information, and then it is determined whether there are defects in the repeating pattern units and non-repeating pattern units based on the difference information. In this way, in the process of wafer defect detection, the SEM image and the pattern units in the design layout are measured to obtain difference information that can represent the SEM image, and then defect detection can be performed on the SEM image based on the difference information. In the process of defect detection, the characteristics of the SEM image and the pattern units in the design layout are fully taken into consideration, so that the determined difference information is more comprehensive and reliable, thereby improving the accuracy and reliability of subsequent wafer defect detection.

[0049] As shown in FIG. 3, the method for detecting wafer defects may include the following steps.

[0050] In step 301, repeating pattern units and non-repeating pattern units in the SEM image are determined based on the SEM image to be detected and the pattern units in the design layout.

[0051] In step 302, the non-repeating pattern unit is divided to obtain a repeating sub-pattern unit and an isolated sub-pattern unit.

[0052] Here, any suitable method may be adopted to divide the non-repeating pattern unit to obtain repeating sub-pattern units and isolated sub-pattern units. For example, the non-repeating pattern unit may be divided according to line width, line end, etc. to obtain sub-pattern units such as line width sub-pattern units, line end sub-pattern units, etc. If a certain sub-pattern unit appears multiple times, i.e., there are multiple occurrences, the sub-pattern unit may be determined to be a repeating sub-pattern unit. If a certain sub-pattern unit appears only once, i.e., there is only one occurrence, the sub-pattern unit may be determined to be an isolated sub-pattern unit. This application is not limited to this.

[0053] In step 303, measurement points are set in the repeating pattern unit and the repeating sub-pattern unit to determine first measurement data.

[0054] Here, the number of measurement points may be one or more, and the type of measurement point may be one or more, and the present application is not limited thereto.

[0055] Here, for repeating pattern units and repeating sub-pattern units of the same type, measurement points may be set according to the same rules, and the repeating pattern units and repeating sub-pattern units may be measured respectively to obtain first measurement data corresponding to the repeating pattern units, first measurement data corresponding to the repeating sub-pattern units, etc., and this application is not limited to this.

[0056] Optionally, the non-repeating pattern unit may be divided according to line width, line end, etc. to obtain repeating sub-pattern units and isolated sub-pattern units, and then a detection window may be set within each repeating sub-pattern unit. For example, a corresponding detection window may be set according to the position, features, etc. of each repeating sub-pattern unit, and the present application is not limited thereto.

[0057] It is understood that the number of detection frames installed for each repeating pattern unit or repeating sub-pattern unit may be one or more, and the present application does not limit the number and type of detection frames installed.

[0058] For example, in the schematic diagram shown in Fig. 4, pattern units 1, 2, 3, and 4 in Fig. 4 are repeating pattern units, and pattern unit 5 is a non-repeating pattern unit. Next, the non-repeating pattern unit is divided to obtain repeating subpattern units, such as line width subpattern units and line end subpattern units, and isolated subpattern units. Furthermore, corresponding detection frames are provided for repeating subpattern units, such that a line width region detection frame is provided for the line width subpattern unit and a line end region detection frame is provided for the line end subpattern unit. A line end region detection frame is provided for repeating subpattern unit 1, which is the black hatched region A in Fig. 4, a line width region detection frame is provided for repeating subpattern unit 2, which is the crossing line region B, and an irregular region C is an isolated subpattern unit.

[0059] Next, in repeating subpattern unit 1, which is black hatched area A, measurement points are set at intervals of n1 μm, so that the repeating subpattern unit corresponding to black hatched area A can be measured to obtain first measurement data corresponding to the line end type. Next, in repeating subpattern unit 2, which is crossing line area B, measurement points are set at intervals of n2 μm, so that the repeating subpattern unit corresponding to crossing line area B can be measured to obtain first measurement data corresponding to the line width type.

[0060] Here, n1 and n2 may be the same or different, and the present application is not limited thereto.

[0061] It can be understood that the area corresponding to the measurement point may have the outline of a repeating pattern unit, the outline of a repeating sub-pattern unit, or may not have the outline of any pattern unit, and this application is not limited thereto.

[0062] It should be noted that the above examples are merely illustrative and do not limit the methods for determining the repeating sub-pattern unit, the isolated sub-pattern unit, and the first measurement data in the embodiments of the present application.

[0063] In step 304, a measurement point is set at the same position of the corresponding target pattern unit in the design layout to determine second measurement data.

[0064] Here, after setting measurement points in the repeating pattern unit and the repeating sub-pattern unit, the same measurement points may be set at the same positions in accordance with the corresponding rules in the target pattern unit corresponding to the repeating pattern unit in the design layout and in the target pattern unit corresponding to the repeating sub-pattern unit, thereby measuring each target pattern unit and obtaining corresponding second measurement data.

[0065] For example, when measurement points are set at intervals of n1 μm in repeating subpattern unit 1, measurement points can be set at the same positions of target pattern unit 1 of the design layout corresponding to repeating subpattern unit 1. For example, measurement points can be set at intervals of n1 μm to measure target pattern unit 1 and obtain second measurement data corresponding to the line end type. When measurement points are set at intervals of n2 μm in repeating subpattern unit 2, measurement points can be set at the same positions of target pattern unit 2 of the design layout corresponding to repeating subpattern unit 2. For example, measurement points can be set at intervals of n2 μm to measure target pattern unit 2 and obtain second measurement data corresponding to the line width type.

[0066] It can be understood that the area corresponding to the measurement point may have an outline of a repeating pattern unit, an outline of a repeating sub-pattern unit, or may not have an outline of any pattern unit, and this application is not limited thereto.

[0067] Here, n1 and n2 may be the same or different, and target pattern unit 1 and target pattern unit 2 may be the same or different, and the present application is not limited thereto.

[0068] In step 305, difference information is determined based on the first measurement data and the second measurement data.

[0069] It can be understood that by measuring a repeating pattern unit, a repeating sub-pattern unit to obtain corresponding first measurement data, and by measuring a target pattern unit in the design layout using the same measurement method to obtain corresponding second measurement data, difference information of the repeating pattern unit in which each measurement point is located relative to the target pattern unit in the design layout, difference information of the repeating sub-pattern unit in which each measurement point is located relative to the target pattern unit in the design layout, etc. can be determined, and the present application is not limited thereto.

[0070] Optionally, the difference information corresponding to each measurement type may be determined based on the measurement type of the first measurement data and the measurement type of the second measurement data, where the measurement type may be multiple, such as a line width type, a line end type, etc., or may be divided into a line width 1 type, a line width 2 type, a line width 3 type, etc. according to different specific values, and the present application is not limited thereto.

[0071] Furthermore, the difference information may be understood as difference data, such as difference values, percentages, etc., between a pattern unit in an SEM image and a pattern unit in a design layout, and is not limited thereto in this application.

[0072] For example, if line width 1 corresponds to interval n1, measurement point 1, measurement point 2, and measurement point 3 are set within repeating subpattern unit 1 at an interval of n1 μm, and the same measurement point 1', measurement point 2', and measurement point 3' are set within target pattern unit 1' in the design layout corresponding to the repeating subpattern unit 1 at an interval of n1 μm, and there is no pattern contour at measurement point 2, then 1 / 3 may be determined as the difference information for contour missing detection corresponding to line width 1; if the first measurement data corresponding to measurement point 1 and measurement point 3 are both 5 μm, and the second measurement data corresponding to measurement point 1' and measurement point 3' are 4.9 μm and 5 μm, respectively, then the difference values ​​between the first measurement data and the second measurement data corresponding to measurement point 1 and measurement point 3 are 0.1 and 0, respectively, and 0.1 and 0 may be determined as the difference information for contour change detection corresponding to line width 1.

[0073] It should be noted that the above examples are merely illustrative and do not limit the method of determining difference information in the embodiments of the present application.

[0074] Optionally, the number of detection frames provided in each of the repeating subpattern unit and the repeating pattern unit may be one or more, and therefore when determining the difference information for missing edge detection, a difference value corresponding to each detection frame may be determined, or a difference value corresponding to a single repeating subpattern unit or repeating pattern unit may be determined. For example, if repeating subpattern unit 3 has a total of three detection frames, each detection frame has five measurement points, and the number of measurement points where a pattern edge does not exist in each detection frame is 1, 0, and 3, respectively, the corresponding difference data for missing edge detection for each detection frame will be 1 / 5, 0, and 3 / 5, respectively, and the corresponding difference data for missing edge detection for repeating subpattern unit 3 will be 4 / 15.

[0075] The above example is merely illustrative and does not limit the method of determining difference information for reliably detecting contours in the embodiments of the present application.

[0076] It can be understood that for each measurement type, the difference information for contour missing detection and the difference information for contour change detection for each measurement type can be determined respectively, and for the related implementation methods, reference can be made to the description of each embodiment of this application, which will not be repeated here.

[0077] Optionally, the detection frames installed in each of the repeating pattern unit and the repeating sub-pattern unit may be of one type or of multiple types. Next, by setting detection points in each of the detection frames according to a certain rule, each of the repeating pattern unit and the repeating sub-pattern unit can be measured.

[0078] In step 306, a mean value and a standard deviation corresponding to the measurement type are determined based on the measurement types of the first measurement data and the second measurement data corresponding to the difference information.

[0079] For example, if the difference information for contour loss detection corresponding to line width 1 is 1 / 3, 2 / 3, 1 / 3, and 2 / 3, respectively, it can be determined that the corresponding average value is 1 / 2 and the standard deviation is 1 / 6. If the difference information for contour change detection corresponding to line width 1 is 0.1, 0, 0, and 0.1, respectively, it can be determined that the corresponding average value is 0.05 and the standard deviation is 0.05.

[0080] Accordingly, the same method can be used to determine the mean value and standard deviation of contour loss detection and the mean value and standard deviation of contour change detection corresponding to different line widths, and the mean value and standard deviation of contour loss detection and the mean value and standard deviation of contour change detection corresponding to different line ends, thereby determining the mean value and standard deviation corresponding to each measurement type.

[0081] It should be noted that the above examples are merely illustrative and do not limit the methods for determining the mean and standard deviation corresponding to the measurement type in the embodiments of the present application.

[0082] In step 307, it is determined whether the repeating pattern unit or repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, the corresponding mean value and standard deviation.

[0083] Optionally, a measurement threshold corresponding to the measurement type is determined based on the mean value and standard deviation corresponding to the measurement type, and then if any of the first measurement data is greater than the measurement threshold of the measurement type, it can be determined that the repeating pattern unit or repeating sub-pattern unit in which any of the first measurement data is located is defective, and the repeating pattern unit or repeating sub-pattern unit in which any of the first measurement data is located can be determined to be an abnormal pattern unit, and the abnormal pattern unit and any of the first measurement data are stored in an abnormal feature library.

[0084] Here, the measurement threshold may not be a predetermined fixed value, but may be determined for each measurement type based on the relationship satisfied by the mean value and standard deviation corresponding to each measurement type, for example.

[0085] Furthermore, the abnormality feature library may include abnormality pattern units, may include measurement data for each abnormality pattern, or may include both, and the present application is not limited to these.

[0086] For example, the number of first measurement data in contour change detection corresponding to the line width 1 measurement type is n, and the average value is

number

number

number

[0087] The number of first measurement data in the contour loss detection corresponding to the line width 1 measurement type is m, and the average value is

number

number

number

[0088] The above example is merely illustrative and does not limit the method of determining an abnormal pattern unit in the embodiments of the present application.

[0089] In step 308, the isolated subpattern unit is matched with anomaly pattern units in the anomaly feature library to determine the degree of matching.

[0090] In step 309, it is determined whether the isolated sub-pattern unit is defective based on the degree of matching.

[0091] Here, the anomaly feature library may store a large number of abnormal pattern units and measurement data corresponding to each abnormal pattern unit, so that an isolated sub-pattern unit may be obtained after dividing the non-repeating unit, and the isolated sub-pattern unit and the abnormal pattern unit may be matched to determine the matching degree between them, and then it may be determined whether the isolated sub-pattern unit is defective based on the matching degree.

[0092] It can be understood that the degree of matching between the isolated sub-pattern unit and the abnormal pattern unit can be determined in various ways, for example, by aligning the isolated sub-pattern unit and the abnormal pattern unit and determining the degree of matching between them based on the size, shape, contour, position, etc. of each isolated sub-pattern unit and the abnormal pattern unit, and the present application is not limited thereto.

[0093] Optionally, an isolated sub-pattern unit may be determined to be defective if the matching degree of the isolated sub-pattern unit is greater than a certain threshold, and the present application is not limited thereto.

[0094] Optionally, the isolated sub-pattern unit may be measured to obtain third measurement data, and the third measurement data may then be compared with the measurement data of each abnormal pattern in the abnormal feature library to determine whether the isolated sub-pattern unit is defective.

[0095] The above example is merely illustrative and does not limit the method of determining an abnormal pattern unit in the embodiments of the present application.

[0096] In an embodiment of the present application, first, repeating pattern units and non-repeating pattern units in the SEM image can be determined based on the SEM image to be detected and the pattern units in the design layout. Then, the non-repeating pattern units are divided to obtain repeating sub-pattern units and isolated sub-pattern units. Measurement points can be set on the repeating pattern units and the repeating sub-pattern units to determine first measurement data. Then, measurement points are set at the same positions of the corresponding target pattern units in the design layout to determine second measurement data. Difference information can be determined based on the first measurement data and the second measurement data. Then, based on the measurement types of the first measurement data and the second measurement data corresponding to the difference information, an average value and a standard deviation corresponding to the measurement type are determined. Then, based on each of the first measurement data corresponding to the measurement type and the corresponding average value and standard deviation, it is determined whether the repeating pattern unit or the repeating sub-pattern unit has a defect. The isolated sub-pattern unit is matched with an abnormal pattern unit in the abnormality feature library to determine the matching degree. Then, based on the matching degree, it is determined whether the isolated sub-pattern unit has a defect. As a result, in the process of wafer defect detection, the SEM image and the pattern units in the design layout are measured to obtain difference information representing the SEM image, and then defect detection can be performed on the SEM image based on the difference information.Since the characteristics of the SEM image and the pattern units in the design layout are fully taken into account in the process of defect detection, the determined difference information is more comprehensive and reliable, which can improve the accuracy and reliability of subsequent wafer defect detection.

[0097] According to the present application, an apparatus for detecting wafer defects is provided, which includes a first determining module 510, a measurement module 520, and a second determining module 530, as shown in FIG.

[0098] Here, the first determination module 510 is used to determine repeating pattern units and non-repeating pattern units in the SEM image based on the SEM image to be detected and pattern units in the design layout; the measurement module 520 is used to measure the pattern units in the design layout, the repeating pattern units, and the non-repeating pattern units to determine difference information; and the second determination module 530 is used to determine whether there are defects in the repeating pattern units and non-repeating pattern units based on the difference information.

[0099] In some embodiments, the first determination module 510 is specifically used to process the SEM image to obtain pattern contours in the SEM image, and match the pattern contours with pattern units in the design layout to determine repeating and non-repeating pattern units in the SEM image.

[0100] In some embodiments, the measurement module 520 includes a division submodule for dividing the non-repeating pattern unit to obtain a repeating sub-pattern unit and an isolated sub-pattern unit, a first determination submodule for setting measurement points in the repeating pattern unit and the repeating sub-pattern unit to determine first measurement data, a second determination submodule for setting measurement points at the same positions of corresponding target pattern units in the design layout to determine second measurement data, and a third determination submodule for determining difference information based on the first measurement data and the second measurement data.

[0101] In some embodiments, the third determination sub-module is used to determine difference information corresponding to each measurement type based on a measurement type of the first measurement data and a measurement type of the second measurement data.

[0102] In some embodiments, the second determination module 530 includes a fourth determination sub-module for determining a mean value and a standard deviation corresponding to the measurement type based on the measurement type of the first measurement data and the second measurement data corresponding to the difference information, and a fifth determination sub-module for determining whether the repeating pattern unit or repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, the corresponding mean value and the standard deviation.

[0103] In some embodiments, the fifth determination submodule includes a first determination unit for determining a measurement threshold corresponding to the measurement type based on a mean value and standard deviation corresponding to the measurement type; a second determination unit for determining that the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located is defective if any of the first measurement data is greater than the measurement threshold of the measurement type; and a third determination unit for determining the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located as an abnormal pattern unit, and storing the abnormal pattern unit and any of the first measurement data in an abnormality feature library.

[0104] In some embodiments, the second determination module 530 is specifically used to match the isolated sub-pattern unit with an abnormal pattern unit in an abnormal feature library to determine the degree of match, and to determine whether the isolated sub-pattern unit is defective based on the degree of match.

[0105] The wafer defect detection apparatus according to the present application first determines repeating pattern units and non-repeating pattern units in the SEM image based on the SEM image to be detected and the pattern units in the design layout, then measures the pattern units, repeating pattern units, and non-repeating pattern units in the design layout to determine difference information, and then determines whether there are defects in the repeating pattern units and non-repeating pattern units based on the difference information. Thus, in the process of wafer defect detection, the SEM image and the pattern units in the design layout are measured to obtain difference information that can represent the SEM image, and then defect detection can be performed on the SEM image based on the difference information. Because the characteristics of the SEM image and the pattern units in the design layout are fully taken into account in the defect detection process, the determined difference information is more comprehensive and reliable, thereby improving the accuracy and reliability of subsequent wafer defect detection.

[0106] It should be understood that specific features, acts, and details described herein with respect to the methods of the present application may equally apply to the apparatus and systems of the present application, and vice versa, and that each step of the methods of the present application described above may be performed by a corresponding component or unit of the apparatus or system of the present application.

[0107] It should be understood that each module / unit of the device of the present application can be realized in whole or in part by software, hardware, firmware, or a combination thereof. Each module / unit may be incorporated into the processor of the electronic device in the form of hardware or firmware, or may be separate from the processor, or may be stored in the memory of the electronic device in the form of software and called by the processor to perform the operations of each module / unit. Each module / unit may be realized as a separate component or module, or two or more modules / units may be realized as a single component or module.

[0108] 6, the present application provides an electronic device 600 including a processor 601 and a memory 602 having computer program instructions stored therein, where the processor 601, when executing the computer program instructions, performs the steps of the method for detecting wafer defects described above. The electronic device 600 may broadly be a server, a terminal, or any other electronic device having the necessary computing and / or processing capabilities.

[0109] In one embodiment, the electronic device 600 may include a processor, memory, a network interface, a communication interface, etc., connected via a system bus. The processor of the electronic device 600 may be used to provide necessary computing, processing, and / or control functions. The memory of the electronic device 600 may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory may provide an environment for the execution of the operating system and computer programs on the non-volatile storage medium. The network interface and communication interface of the electronic device 600 are used to connect and communicate with external devices via a network. When the computer program is executed by the processor, the steps of the method of the present application are performed.

[0110] The present application provides a computer-readable storage medium having stored thereon computer program instructions which, when executed by a processor, implement the above-mentioned method for detecting wafer defects.

[0111] Those skilled in the art will understand that the method steps of the present application can be completed by instructing relevant hardware, such as the electronic device 600 or a processor, through a computer program, which may be stored in a non-transitory computer-readable storage medium, and that the steps of the present application are performed when the computer program is executed. In some cases, any reference to memory, storage, or other medium herein may include non-volatile or volatile memory. Non-volatile memory includes read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid-state disks, etc. Volatile memory includes random access memory (RAM) and external cache memory.

[0112] The above-mentioned technical features can be arbitrarily combined. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be included in the present specification if not contradictory.

[0113] Finally, it should be noted that each of the above embodiments is used only to illustrate the present application, rather than to limit it; although the present application has been described in detail with reference to each of the above examples, those skilled in the art can still modify the technical solutions described in each of the above examples, or equivalently replace some or all of the technical features, and these modifications or replacements will not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the examples of the present application.

Claims

1. determining repeating pattern units and non-repeating pattern units in the SEM image based on the SEM image to be detected and pattern units in the design layout; measuring pattern units, the repeating pattern units, and the non-repeating pattern units in the design layout to determine difference information; determining whether the repeating pattern units and the non-repeating pattern units are defective based on the difference information. A method for detecting wafer defects.

2. Determining the repeating pattern units and the non-repeating pattern units in the SEM image based on the pattern units in the SEM image and the design layout that are the detection target includes: processing the SEM image to obtain a pattern profile within the SEM image; matching the pattern contours with pattern units in the design layout to determine the repeating and non-repeating pattern units in the SEM image; The method for detecting wafer defects according to claim 1 .

3. Measuring pattern units, the repeating pattern units, and the non-repeating pattern units in the design layout to determine difference information includes: Dividing the non-repeating pattern unit to obtain a repeating sub-pattern unit and an isolated sub-pattern unit; setting measurement points in the repeating pattern unit and the repeating sub-pattern unit to determine first measurement data; determining second measurement data by setting a measurement point at the same position of a corresponding target pattern unit in the design layout; determining difference information based on the first measurement data and the second measurement data. The method for detecting wafer defects according to claim 1 .

4. Determining difference information based on the first measurement data and the second measurement data includes: determining difference information corresponding to each measurement type based on a measurement type of the first measurement data and a measurement type of the second measurement data, respectively; The method for detecting wafer defects according to claim 3 .

5. determining whether the repeating pattern units and the non-repeating pattern units are defective based on the difference information; determining a mean value and a standard deviation corresponding to the measurement type based on the measurement type of the first measurement data and the second measurement data corresponding to the difference information; determining whether the repeating pattern unit or the repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, a corresponding mean value and a standard deviation. The method for detecting wafer defects according to claim 4.

6. determining whether the repeating pattern unit or the repeating sub-pattern unit is defective based on each of the first measurement data corresponding to the measurement type, a corresponding mean value and a standard deviation; determining a measurement threshold corresponding to the measurement type based on a mean value and a standard deviation corresponding to the measurement type; determining that the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located is defective if any of the first measurement data is greater than a measurement threshold for the measurement type; determining the repeating pattern unit or the repeating sub-pattern unit in which any of the first measurement data is located as an abnormal pattern unit, and storing the abnormal pattern unit and any of the first measurement data in an abnormality feature library; The method for detecting wafer defects according to claim 5.

7. determining whether the repeating pattern units and the non-repeating pattern units are defective based on the difference information; matching the isolated sub-pattern unit with an abnormal pattern unit in an anomaly feature library to determine a degree of match; and determining whether the isolated sub-pattern unit is defective based on the degree of matching. The method for detecting wafer defects according to claim 3 .

8. a first determination module for determining repeating pattern units and non-repeating pattern units in the SEM image based on the SEM image to be detected and pattern units in the design layout; a measurement module for measuring pattern units, the repeating pattern units, and the non-repeating pattern units in the design layout to determine difference information; a second determining module for determining whether the repeating pattern unit and the non-repeating pattern unit are defective based on the difference information. A device that detects wafer defects.

9. a processor and a memory having computer program instructions stored therein; When the processor executes the computer program instructions, the method for detecting wafer defects according to any one of claims 1 to 7 is implemented. electronic equipment.

10. A computer-readable storage medium having computer program instructions stored thereon, comprising: When the computer program instructions are executed by a processor, the method for detecting wafer defects according to any one of claims 1 to 7 is implemented. A computer-readable storage medium.

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