A method and device for obtaining a layout

Abstract

The embodiment of the present application discloses a layout acquisition method and device. After obtaining an initial image obtained by scanning an etched pattern using a scanning electron microscope, since the initial image has the characteristics of the etched pattern, the initial image can be used to predict the layout of the etched pattern. Specifically, the contour of the initial image can be extracted to obtain the contour information of the etched pattern. The initial image can have a ruler for characterizing the size of the etched pattern. In this way, using the contour information of the etched pattern and the ruler of the initial image, a predicted layout with size and graphic contour characteristics corresponding to the etched pattern can be generated. The generated predicted layout can accurately reflect the actual characteristics of the etched pattern. The accurate predicted layout is conducive to the analysis of the etched pattern, or the generated predicted layout can be further compared with the actual original layout to analyze the etching process.

Description

Technical Field

[0001] The present application relates to the semiconductor field, and in particular to a layout acquisition method and device. Background Art

[0002] In the semiconductor field, photolithography is an important process in the production of integrated circuits. Specifically, the original design pattern on the mask (i.e., the original layout) can be transferred to the photoresist layer in a certain proportion through exposure, and then transferred from the photoresist layer to the object to be processed to obtain an etched pattern, thereby providing conditions for obtaining a circuit with a predetermined target function. Generally speaking, the shape of the etched pattern is basically the same as that of the original layout.

[0003] For example, a photoresist layer can be formed on a metal layer, and a photoresist pattern can be formed on the metal layer after photolithography. Then, the metal layer is etched using the photoresist pattern to obtain a metal pattern. Normally, the photoresist pattern is almost the same as the original layout, and the metal pattern is almost the same as the photoresist pattern, that is, the metal pattern is also almost the same as the original layout.

[0004] However, the actual etched pattern may have deviations. How to accurately analyze the etched pattern is an important issue in this field. Summary of the invention

[0005] In order to solve the above technical problems, the embodiments of the present application provide a layout acquisition method and device, which can use the etching pattern to acquire the corresponding layout and realize accurate analysis of the etching pattern.

[0006] The present application provides a layout acquisition method, the method comprising:

[0007] Obtaining an initial image obtained by scanning the etched pattern using a scanning electron microscope;

[0008] Performing contour extraction on the initial image to obtain contour information of the etching pattern;

[0009] The predicted layout corresponding to the etched pattern is generated by using the contour information and the scale of the initial image.

[0010] Optionally, the extracting contour of the initial image to obtain contour information of the etched pattern includes:

[0011] Performing grayscale processing on the initial image to obtain a grayscale image;

[0012] Binarizing the grayscale image to obtain a binary image;

[0013] The binary image is subjected to contour extraction to obtain contour information of the etching pattern.

[0014] Optionally, before binarizing the grayscale image, the method further includes:

[0015] Perform median filtering on the grayscale image.

[0016] Optionally, the performing contour extraction on the binary image to obtain contour information of the etching pattern includes:

[0017] Performing contour extraction on the binary image to obtain the contour in the binary image;

[0018] In the contour of the binary image, the contour of the region whose area in the binary image is smaller than the area threshold is removed to obtain the contour information of the etched pattern.

[0019] Optionally, the etched pattern is an etched pattern obtained by etching a metal layer.

[0020] Optionally, the etching pattern is obtained by etching using an original layout, and the method further comprises:

[0021] The original layout is adjusted according to the predicted layout.

[0022] The present application also provides a layout acquisition device, the device comprising:

[0023] An initial image acquisition unit, used to acquire an initial image obtained by scanning the etched pattern using a scanning electron microscope;

[0024] A contour information acquisition unit, used for performing contour extraction on the initial image to obtain contour information of the etching pattern;

[0025] The predicted layout generation unit is used to generate a predicted layout corresponding to the etching pattern by using the contour information and the scale of the initial image.

[0026] Optionally, the profile information acquiring unit includes:

[0027] A grayscale unit, used for grayscale processing the initial image to obtain a grayscale image;

[0028] A binarization unit, used for performing binarization processing on the grayscale image to obtain a binary image;

[0029] The contour information acquisition subunit is used to extract the contour of the binary image to obtain the contour information of the etching pattern.

[0030] Optionally, the device further comprises:

[0031] The filtering unit is used to perform median filtering on the grayscale image before performing binary conversion on the grayscale image.

[0032] Optionally, the profile information acquisition subunit includes:

[0033] A contour extraction unit, used for performing contour extraction on the binary image to obtain a contour in the binary image;

[0034] The contour adjustment unit is used to remove the contour of the region whose area in the binary image is smaller than the area threshold in the contour of the binary image, so as to obtain the contour information of the etching pattern.

[0035] Optionally, the etched pattern is an etched pattern obtained by etching a metal layer.

[0036] Optionally, the etching pattern is obtained by etching using an original layout, and the device further comprises:

[0037] A layout adjustment unit is used to adjust the original layout according to the predicted layout.

[0038] The embodiment of the present application provides a layout acquisition method and device. After obtaining an initial image obtained by scanning an etched pattern using a scanning electron microscope, since the initial image has the characteristics of the etched pattern, the initial image can be used to predict the layout of the etched pattern. Specifically, the contour of the initial image can be extracted to obtain the contour information of the etched pattern. The initial image can have a ruler for characterizing the size of the etched pattern. In this way, using the contour information of the etched pattern and the ruler of the initial image, a predicted layout with size and graphic contour characteristics corresponding to the etched pattern can be generated. The generated predicted layout can accurately reflect the actual characteristics of the etched pattern. The accurate predicted layout is conducive to the analysis of the etched pattern, or the generated predicted layout can be further compared with the actual original layout to analyze the etching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0040] Figure 1 A flowchart of a layout acquisition method provided in an embodiment of the present application;

[0041] Figure 2 A schematic diagram of an initial image provided in an embodiment of the present application;

[0042] Figure 3is a schematic diagram of a grayscale image in an embodiment of the present application;

[0043] Figure 4 is a schematic diagram of a grayscale image that has been subjected to median filtering in an embodiment of the present application;

[0044] Figure 5 A schematic diagram of a binary image in an application embodiment;

[0045] Figure 6 A schematic diagram of a portion of a binary image in an embodiment of the present application;

[0046] Figure 7 A schematic diagram of another part of the binary image in an embodiment of the present application;

[0047] Figure 8 A schematic diagram of a prediction layout provided in an embodiment of the present application;

[0048] Fig. 9 A structural block diagram of a layout acquisition device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0050] At present, the etched pattern can be obtained by photolithography and etching. Normally, the etched pattern is almost the same as the original layout. The shape of the etched pattern can be controlled by controlling the shape of the original layout. However, the actual etched pattern may have deviations, so in actual operation, the etched pattern can be analyzed to compare the difference between the etched pattern and the original layout.

[0051] Based on the above technical problems, an embodiment of the present application provides a layout acquisition method and device. After obtaining an initial image obtained by scanning an etched pattern using a scanning electron microscope, since the initial image has the characteristics of the etched pattern, the initial image can be used to predict the layout of the etched pattern. Specifically, the contour of the initial image can be extracted to obtain the contour information of the etched pattern. The initial image can have a ruler used to characterize the size of the etched pattern. In this way, using the contour information of the etched pattern and the ruler of the initial image, a predicted layout with size and graphic contour characteristics corresponding to the etched pattern can be generated. The generated predicted layout can accurately reflect the actual characteristics of the etched pattern. The accurate predicted layout is conducive to the analysis of the etched pattern, or the generated predicted layout can be further compared with the actual original layout to analyze the etching process.

[0052] The specific implementation of a layout acquisition method and device in the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0053] refer to Figure 1 FIG. 1 is a flowchart of a layout acquisition method provided in an embodiment of the present application. The method may include the following steps:

[0054] S101, obtaining an initial image by scanning the etched pattern using a scanning electron microscope.

[0055] In an embodiment of the present application, the etched pattern may be a pattern obtained after photolithography and etching in the film layer to be etched, and the layout used in the photolithography process may be used as the original layout, or it may be said that the film layer to be etched may be etched using the original layout to obtain an etched pattern, and the format of the original layout may be .gds, etc. The etched pattern may be a pattern obtained by etching a semiconductor film layer, or it may be a pattern obtained by etching a conductor film layer. In an embodiment of the present application, the etched pattern is illustrated by taking an etched pattern obtained by etching a metal layer as an example. The etched pattern may include at least one of the following patterns: a line pattern, a square pattern, a rectangular pattern, an L-shaped pattern, a U-shaped pattern, a T-shaped pattern, an H-shaped pattern, etc.

[0056] After etching to obtain the etching pattern, the etching can be scanned using a scanning electron microscope (SEM), which is also called a scanning electron microscope. It is an electron microscope that uses an electron beam to scan the surface of a sample to obtain sample information. Scanning the etching pattern using a scanning electron microscope can obtain an initial image, and the initial image can have the shape characteristics of the etching pattern. Therefore, analyzing the initial image can obtain the characteristics of the etching pattern, and the initial image can also be used to predict the layout of the etching pattern. For example, it can be determined whether there are possible defects such as bad spots, loss, redundancy, etc. in the etching pattern, and the overall circuit performance can also be predicted by analyzing the etching pattern. Among them, the initial image obtained by scanning the etching pattern using a scanning electron microscope can be in a picture format, such as .jpg or .png.

[0057] Specifically, the color of the initial image can reflect the interaction between the film layer to be etched and the electron beam, and is used to reflect the morphology of the film layer to be etched, thus including the characteristics of the etched pattern in the film layer to be etched. Patterns at the same height can have approximately the same color. The initial image may also include a ruler to indicate the actual distance represented by the pixel distance in the initial image, thereby reflecting the size of the etched pattern. According to the ruler of the initial image, the geometric measurement data such as the line width and spacing of the main pattern can be determined. Figure 2 As shown, it is a schematic diagram of an initial image provided in an embodiment of the present application, wherein the lighter longitudinal strips are metal layers, the lighter circles whose diameters are consistent with the widths of the longitudinal strips are metal through holes on the metal layer (in the middle elliptical circle), the circles whose diameters are smaller than the widths of the longitudinal strips are stray points (in the left elliptical circle), and the darker transverse strips are metal layers of other layers below the metal layer. The lighter longitudinal strips can be used as etching patterns that need to be analyzed, and the distance between the two metal through holes on the right is 125 nanometers (nm).

[0058] After the initial image is obtained by scanning with a scanning electron microscope, the initial image may be saved in a database. Then, obtaining the initial image may specifically include reading the initial image from the database.

[0059] S102, extracting the contour of the initial image to obtain contour information of the etching pattern.

[0060] After the initial image is acquired, contour extraction can be performed on the initial image to obtain contour information of the etched pattern. The contour information can characterize the characteristics of the etched pattern, so that the layout corresponding to the etched pattern can be predicted using the contour information of the etched pattern.

[0061] Before performing contour extraction on the initial image, the initial image can be grayed to obtain a gray image, and then the gray image can be binarized to obtain a binary image, so that contour extraction can be performed on the binary image to obtain contour information of the etching pattern. Compared with directly extracting the polar contour of the initial image, contour extraction on the binary image has higher convenience and accuracy.

[0062] Specifically, grayscale processing refers to the process of changing an image containing brightness and color into a grayscale image. Figure 3 , which is a schematic diagram of a grayscale image in an embodiment of the present application, wherein the grayscale image is a part of the initial image.

[0063] In addition, before the grayscale image is converted into a binary value, the grayscale image can also be subjected to median filtering to suppress the noise in the grayscale image. Specifically, median filtering is a nonlinear signal processing technology based on sorting statistics theory. The basic principle is to replace the value of a point in a digital image or digital sequence with the median value of each point in a neighborhood of the point, so that the surrounding pixel values ​​are close to the true value, thereby eliminating isolated noise points. There are many different ways to median filtering, which can be determined according to actual conditions in actual operations. Reference Figure 4 , which is a schematic diagram of a grayscale image that has undergone median filtering in an embodiment of the present application.

[0064] Specifically, binarization refers to setting the grayscale values ​​of pixels on an image to different values, such as 0 and 255, so that the entire image presents an obvious black and white effect, reducing the amount of data in the image and highlighting the contours in the image. Specifically, a threshold can be set for the grayscale image, so that the numerical values ​​on both sides of the threshold are set to different values. There are many different ways to determine the threshold, such as the Otsu method - maximum between-class variance method (OTSU). Reference Figure 5 FIG. 1 is a schematic diagram of a binary image in an embodiment of the application. Figure 5 In the etching pattern shown in , the boundary of the image will affect the area division, and the white area is the metal area. The width of the outermost black area can be set to zero, thereby forming multiple closed areas in the binary image. The removal of the black area does not affect the shape of the etching pattern.

[0065] After performing contour extraction on the binary image, the contour information of the etched pattern can be obtained. Specifically, contour extraction can be performed on the binary image to obtain the contour in the binary image. After that, the contour in the binary image can be directly used as the contour information of the etched pattern, or after removing the contour of the stray area from the contour of the binary image, the remaining contour can be used as the contour information of the etched pattern.

[0066] The contour extraction of the binary image is based on the pixel difference in the binary image. The contour extraction can be implemented using a contour extraction algorithm. The contour in the binary image obtained by contour extraction is the position where the pixel difference exists in the binary image. Therefore, the contour extracted in the binary image can be used as the contour information of the etching pattern.

[0067] In addition, there may be stray points in the binary image, which may be caused by the uneven distribution of the material of the film to be etched, the uneven distribution of the electron beam during the initial image acquisition process, or the algorithm error of the grayscale processing or binarization process. Therefore, the contour in the binary image includes not only the boundary position of the etched pattern, but also the boundary position of the stray points. The area of ​​the location of the stray points is usually small. Figure 6 and Figure 7 , which is a schematic diagram of a partial area of ​​a binary image in an embodiment of the present application, Figure 6 In the figure on the left, there may be some small white areas in the black area. The white areas can be considered as stray points. The contours in the binary image include the contours of the stray points. Figure 7 In the figure on the left, there may be some smaller black areas in the white area. The black areas can be considered as stray points, and the contours in the binary image include the contours of the stray points.

[0068] Therefore, in an embodiment of the present application, the regions in the binary image whose area is smaller than the area threshold can be regarded as the regions where the stray points are located, and the contours of these regions can be removed. The area threshold can be determined according to the actual situation, for example, according to the critical size that can be achieved by lithography. Figure 6 The figure on the right shows a binary image after removing the small white areas in the black areas. Figure 7 The figure on the right shows a binary image after removing the smaller black areas in the white areas, thereby further removing the noise in the binary image.

[0069] S103, using the contour information and the scale of the initial image, generating a predicted layout corresponding to the etching pattern.

[0070] After obtaining the contour information of the etching pattern, a predicted layout corresponding to the etching pattern can be generated according to the contour information of the etching pattern and the scale of the initial image. The predicted layout can have size and pattern contour features. Figure 8 As shown, a schematic diagram of a predicted layout provided by an embodiment of the present application is shown. Specifically, the coordinates of the outline of the etched pattern can be determined according to the scale of the initial image, the layout can be drawn, and the area surrounded by the outline can be filled to generate a predicted layout. The format of the predicted layout can be .gds, thereby realizing the processing process from the image of the etched pattern to the layout.

[0071] After obtaining the predicted layout, since the predicted layout can accurately reflect the actual characteristics of the etched pattern, the accurate predicted layout is conducive to the analysis of the etched pattern. For example, the predicted layout can be compared with the original layout to obtain the difference between the predicted layout and the original layout, such as possible bad points, loss, redundancy and other problems. Of course, since the predicted layout is the etched pattern in the actual film layer to be etched, the original layout can be adjusted according to the predicted layout, so that the adjusted layout can obtain an etched pattern that is more in line with the expected one and can better meet actual needs.

[0072] After obtaining the predicted layout, you can also use software to simulate the predicted layout to predict the entire circuit. Usually, the simulation software only supports files in .gds format, so it can better meet actual needs.

[0073] The embodiment of the present application provides a layout acquisition method. After obtaining an initial image obtained by scanning an etched pattern using a scanning electron microscope, since the initial image has the characteristics of the etched pattern, the initial image can be used to predict the layout of the etched pattern. Specifically, the initial image can be contour extracted to obtain the contour information of the etched pattern. The initial image can have a ruler used to characterize the size of the etched pattern. In this way, using the contour information of the etched pattern and the ruler of the initial image, a predicted layout with size and graphic contour characteristics corresponding to the etched pattern can be generated. The generated predicted layout can accurately reflect the actual characteristics of the etched pattern. An accurate predicted layout is conducive to the analysis of the etched pattern. Alternatively, in the case of having an actual original layout, the generated predicted layout can be further compared with the original layout, so as to analyze or improve the etching process. Among them, the original layout is the layout actually used to obtain the etched pattern.

[0074] Based on the above layout acquisition method, the present application embodiment also provides a layout acquisition device, referring to Fig. 9 As shown, it is a structural block diagram of a layout acquisition device provided in an embodiment of the present application, and the device may include:

[0075] An initial image acquisition unit 110 is used to acquire an initial image obtained by scanning the etched pattern using a scanning electron microscope;

[0076] A contour information acquisition unit 120, configured to extract contours from the initial image to obtain contour information of the etched pattern;

[0077] The predicted layout generation unit 130 is used to generate a predicted layout corresponding to the etching pattern by using the contour information and the scale of the initial image.

[0078] Optionally, the profile information acquiring unit includes:

[0079] A grayscale unit, used for grayscale processing the initial image to obtain a grayscale image;

[0080] A binarization unit, used for performing binarization processing on the grayscale image to obtain a binary image;

[0081] The contour information acquisition subunit is used to extract the contour of the binary image to obtain the contour information of the etching pattern.

[0082] Optionally, the device further comprises:

[0083] The filtering unit is used to perform median filtering on the grayscale image before performing binary conversion on the grayscale image.

[0084] Optionally, the profile information acquisition subunit includes:

[0085] A contour extraction unit, used for performing contour extraction on the binary image to obtain a contour in the binary image;

[0086] The contour adjustment unit is used to remove the contour of the region whose area in the binary image is smaller than the area threshold in the contour of the binary image, so as to obtain the contour information of the etching pattern.

[0087] Optionally, the etched pattern is an etched pattern obtained by etching a metal layer.

[0088] Optionally, the etching pattern is obtained by etching using an original layout, and the device further comprises:

[0089] A layout adjustment unit is used to adjust the original layout according to the predicted layout.

[0090] The embodiment of the present application provides a layout acquisition device. After obtaining the initial image obtained by scanning the etching pattern using a scanning electron microscope, since the initial image has the characteristics of the etching pattern, the initial image can be used to predict the layout of the etching pattern. Specifically, the initial image can be contour extracted to obtain the contour information of the etching pattern. The initial image can have a ruler used to characterize the size of the etching pattern. In this way, using the contour information of the etching pattern and the ruler of the initial image, a predicted layout with size and graphic contour characteristics corresponding to the etching pattern can be generated. The generated predicted layout can accurately reflect the actual characteristics of the etching pattern. An accurate predicted layout is conducive to the analysis of the etching pattern, or in the case of having an actual original layout, the generated predicted layout can be further compared with the original layout, so as to analyze or improve the etching process. Among them, the original layout is the layout actually used to obtain the etching pattern.

[0091] Through the description of the above implementation methods, it can be known that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a storage medium, such as a read-only memory (ROM) / RAM, a magnetic disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in each embodiment of the present application or some parts of the embodiments.

[0092] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The equipment and system embodiments described above are merely schematic, in which the modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[0093] The above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the present application, and these improvements and modifications should also be regarded as the protection scope of the present application.

Claims

1. A layout acquisition method, characterized in that: The method comprises: Acquire an initial image obtained by scanning an etched pattern using a scanning electron microscope, wherein the etched pattern is a pattern obtained by photolithography and etching in the film layer to be etched, and the color of the initial image is used to reflect the morphology of the film layer to be etched; Performing contour extraction on the initial image to obtain contour information of the etched pattern, wherein the etched pattern is a pattern with a preset color in the initial image, and the etched pattern is an etched pattern obtained by etching the metal layer; Using the outline information and the scale of the initial image, a predicted layout corresponding to the etched pattern is generated, wherein the predicted layout has size and pattern outline features; Simulating the predicted layout to perform circuit prediction; The step of extracting the contour of the initial image to obtain contour information of the etching pattern includes: Performing grayscale processing on the initial image to obtain a grayscale image; Performing median filtering on the grayscale image; Binarizing the grayscale image to obtain a binary image; Performing contour extraction on the binary image to obtain contour information of the etching pattern; The step of extracting the contour of the binary image to obtain the contour information of the etching pattern includes: Performing contour extraction on the binary image to obtain the contour in the binary image; In the contour of the binary image, the contour of the region whose area in the binary image is smaller than the area threshold is removed to obtain the contour information of the etched pattern.

2. The method according to claim 1, characterized in that The etching pattern is obtained by etching using the original layout, and the method further comprises: The original layout is adjusted according to the predicted layout.

3. A layout acquisition device, characterized in that: The device comprises: An initial image acquisition unit, used to acquire an initial image obtained by scanning an etching pattern using a scanning electron microscope, wherein the etching pattern is a pattern obtained by photolithography and etching in the film layer to be etched, and the color of the initial image is used to reflect the morphology of the film layer to be etched; A contour information acquisition unit, used to extract the contour of the initial image to obtain contour information of the etched pattern, wherein the etched pattern is a pattern with a preset color in the initial image, and the etched pattern is an etched pattern obtained by etching the metal layer; A predicted layout generation unit is used to generate a predicted layout corresponding to the etched pattern using the contour information and the scale of the initial image, wherein the predicted layout has size and pattern contour features; and simulate the predicted layout to perform circuit prediction; The contour information acquisition unit comprises: A grayscale unit, used for grayscale processing the initial image to obtain a grayscale image; A binarization unit, used for performing binarization processing on the grayscale image to obtain a binary image; A contour information acquisition subunit, used for performing contour extraction on the binary image to obtain contour information of the etching pattern; A filtering unit, used for performing median filtering on the grayscale image before performing binary conversion on the grayscale image; The profile information acquisition subunit includes: A contour extraction unit, used for performing contour extraction on the binary image to obtain a contour in the binary image; The contour adjustment unit is used to remove the contour of the region whose area in the binary image is smaller than the area threshold in the contour of the binary image, so as to obtain the contour information of the etching pattern.

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