Graphic size measurement method and system, equipment, storage medium and computer program product

Abstract

The invention discloses a graph size measuring method and system, equipment, a storage medium and a computer program product, and the method comprises the steps: providing a design layout which comprises a plurality of design graphs; obtaining an image of an actual exposure structure corresponding to the design layout, wherein the image comprises a plurality of exposure patterns; aligning an exposure pattern in the image with a corresponding design pattern in the design layout to obtain an alignment position of the image in the design layout; based on the alignment position, combining the design layout and the image to obtain a target contour of the exposure pattern in the image; and obtaining the size of the exposure pattern through the target contour. The method is beneficial for optimizing the OPC model and improving predictability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a method and system for measuring graphic dimensions, an apparatus, a storage medium, and a computer program product. Background Technology

[0002] In recent years, with the rapid development of semiconductor chip manufacturing technology, feature sizes have become smaller and smaller, and optical proximity effects have become stronger and more difficult to predict. In order to build high-quality optical proximity correction (OPC) models, the number of wafer samples used for OPC models has increased dramatically, from thousands to hundreds of thousands.

[0003] Traditional OPC model sample measurement methods utilize critical-dimensional scanning electron microscopy (CD-SEM) supported by a design scale. Currently, the data collection cycle for a single OPC model layer exceeds one month, which is extremely time-consuming. Furthermore, due to the long CD-SEM measurement cycle, the performance of the photoresist (PR) can change, leading to inaccurate subsequent data. Summary of the Invention

[0004] The problem solved by the embodiments of the present invention is to provide a method, system, device, storage medium and computer program product for measuring graphic dimensions, which is beneficial for optimizing OPC models and improving predictability.

[0005] To address the aforementioned problems, embodiments of the present invention provide a graphic size measurement method, comprising: providing a design layout, including multiple design graphics; acquiring an image of the actual exposure structure corresponding to the design layout, the image including multiple exposure graphics; acquiring an alignment position of the image in the design layout by aligning the exposure graphics in the image with the corresponding design graphics in the design layout; acquiring a target contour of the exposure graphics in the image based on the alignment position, combined with the design layout and the image; and obtaining the size of the exposure graphics through the target contour.

[0006] Optionally, an image of the actual exposure structure corresponding to the design layout is obtained. The image includes multiple exposure patterns, including: image acquisition of the actual exposure structure using electron beam scanning to obtain an image of the actual exposure structure.

[0007] Optionally, an image of the actual exposed structure is acquired using electron beam scanning, including: setting a scanning area in the actual exposed structure; determining the scanning position in the scanning area; setting the scanning field of view of the electron beam scanning; and acquiring an image of the actual exposed structure based on the scanning area, scanning position, and scanning field of view.

[0008] Optionally, the alignment position of the image in the design layout is obtained by aligning the exposure pattern in the image with the corresponding design pattern in the design layout, including: extracting the initial outline of the exposure pattern in the image; and obtaining the alignment position of the image in the design layout by aligning the initial outline with the corresponding design pattern.

[0009] Optionally, extracting the initial contour of the exposed pattern in the image includes: obtaining the grayscale distribution of the image, which includes the grayscale level corresponding to each point in the image; and extracting the position of the point in the image corresponding to the grayscale level higher than a preset threshold as the initial contour.

[0010] Optionally, before extracting the positions of points in the image corresponding to gray levels higher than a preset threshold as the initial contour, the method further includes: performing a first smoothing process on the gray distribution of the image; and extracting the positions of points in the image corresponding to gray levels higher than a preset threshold as the initial contour from the gray distribution after the first smoothing process.

[0011] Optionally, a first Gaussian filter is used to perform a first smoothing process on the grayscale distribution of the image.

[0012] Optionally, in the first smoothing process of the image's grayscale distribution using a first Gaussian filter, the expression is used. Perform the first smoothing process, where (x,y) are the coordinates of the point corresponding to the gray level, and σ is the first preset parameter.

[0013] Optionally, the alignment position of the image in the design layout is obtained by aligning the initial outline with the corresponding design graphic, including: overlapping the image with the corresponding area in the design layout; generating an edge extension area surrounding and covering the edge of the design graphic inside and outside the design graphic based on the edge of the design graphic corresponding to the exposure graphic; and obtaining the relative position of the image in the design layout when the overlap rate between the initial outline and the edge extension area is maximized as the alignment position.

[0014] Optionally, overlapping the image with the corresponding area in the design layout includes: setting a portion of the area corresponding to the image in the design layout as a defined area; overlapping the image into the defined area of ​​the design layout; obtaining the relative position of the image in the design layout when the overlap rate between the initial contour and the edge extension area is maximized as the alignment position, including: setting a search step size; performing multiple search processes in the defined area, the search processes including: moving the image to the search position based on the search step size; obtaining the ratio of the total overlap area between the initial contour and the edge extension area to the total area of ​​the edge extension area in the image at the search position as the overlap rate; obtaining the search position corresponding to the maximum overlap rate as the alignment position.

[0015] Optionally, the corresponding coordinates between the image and the design layout are aligned to overlay the image onto the defined area of ​​the design layout.

[0016] Optionally, based on the alignment position, and in combination with the design layout and the image, the target contour of the exposure graphic in the image is obtained, including: overlapping the image with the design layout at the alignment position; obtaining the grayscale distribution of the image, which includes the grayscale level corresponding to each point in the image; selecting the point corresponding to the grayscale level equal to a preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image; and connecting multiple target edge points to form the target contour.

[0017] Optionally, before selecting a point with a gray level equal to a preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, the method further includes: generating an edge extension region surrounding and covering the edge of the design graphic, based on the edge of the design graphic corresponding to the exposure graphic; using the area mapped by the edge extension region in the image as the detection area; selecting a point with a gray level equal to a preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, including: selecting a point with a gray level equal to a preset threshold as an initial edge point in the detection area; selecting one of the initial edge points as the target edge point in the direction perpendicular to the extension of the detection area when there are two initial edge points in the detection area; and selecting the initial edge point as the target edge point in the direction perpendicular to the extension of the detection area when there is one initial edge point in the detection area.

[0018] Optionally, when there are two initial edge points in the detection area, one of the initial edge points is selected as the target edge point, including: determining whether the exposure pattern corresponding to the detection area is suitable for measuring the structural size or the structural interval; when the exposure pattern corresponding to the detection area is suitable for measuring the structural size, selecting an initial edge point that is far from the interior of the corresponding design pattern in the extension direction perpendicular to the detection area as the target edge point; when the exposure pattern corresponding to the detection area is suitable for measuring the structural interval, selecting an initial edge point that is close to the interior of the corresponding design pattern in the extension direction perpendicular to the detection area as the target edge point.

[0019] Optionally, before selecting the point corresponding to the gray level equal to the preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, the method further includes: performing a second smoothing process on the gray level distribution of the image.

[0020] Optionally, a second Gaussian filter is used to perform a second smoothing process on the grayscale distribution of the image.

[0021] Optionally, in the second smoothing process of the image's grayscale distribution using a second Gaussian filter, the expression is used. A second smoothing process is performed, where (x,y) are the coordinates of the point corresponding to the gray level, ρ1 is the second preset parameter, and ρ2 is the third preset parameter.

[0022] Optionally, multiple target edge points can be connected to form a target contour, and edge fitting can be performed by combining multiple target edge points to obtain the target contour.

[0023] Optionally, before obtaining the size of the exposure pattern from the target contour, the method further includes: overlapping the image with the design layout at the alignment position; calculating the edge placement error between each edge of each target contour in the image and the corresponding design pattern; and adjusting the target contour based on the edge placement error.

[0024] Optionally, adjusting the target contour based on edge placement error includes: obtaining half of the average difference of edge placement errors of opposite sides extending horizontally for each target contour in the image, as a first adjustment value; obtaining half of the average difference of edge placement errors of opposite sides extending vertically for each target contour in the image, as a second adjustment value; shifting each target contour vertically in the opposite direction to the first adjustment value by the absolute value of the first adjustment value; and shifting each target contour horizontally in the opposite direction to the second adjustment value by the absolute value of the second adjustment value.

[0025] Optionally, the dimensions of the exposure pattern are obtained from the target contour, including: defining measurement marks on the image; taking measurements at the locations of the measurement marks; or providing a dimension file, including coordinates corresponding to the image and the measurement type corresponding to the coordinates; and obtaining the measurement results of the image based on the dimension file.

[0026] Accordingly, embodiments of the present invention also provide a graphic size measurement system, comprising: a design layout providing module for providing a design layout, including multiple design graphics; an image acquisition module for acquiring an image of the actual exposure structure corresponding to the design layout, the image including multiple exposure graphics; an image alignment module for acquiring the alignment position of the image in the design layout by aligning the exposure graphics in the image with the corresponding design graphics in the design layout; a target contour acquisition module for acquiring the target contour of the exposure graphics in the image based on the alignment position, combined with the design layout and the image; and a measurement module for obtaining the size of the exposure graphics through the target contour.

[0027] Accordingly, embodiments of the present invention also provide a device including at least one memory and at least one processor, wherein the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the graphic size measurement method provided in the embodiments of the present invention.

[0028] Accordingly, embodiments of the present invention also provide a storage medium storing one or more computer instructions, which are used to implement the graphic dimension measurement method provided in the embodiments of the present invention.

[0029] Accordingly, embodiments of the present invention also provide a computer program product, including computer program / instructions, characterized in that, when the computer program / instructions are executed by a processor, they implement the graphic size measurement method provided in the embodiments of the present invention.

[0030] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0031] In the graphic size measurement method provided by this invention, the alignment position of the image in the design layout is obtained by aligning the exposed graphic in the image with the corresponding design graphic in the design layout. Based on the alignment position, the target contour of the exposed graphic in the image is obtained by combining the design layout and the image. The size of the exposed graphic is obtained through the target contour. In this invention, the alignment position of the image in the design layout is obtained first, and then the target contour of the exposed graphic in the image is obtained based on the alignment position and combining the design layout and the image. This is beneficial for more accurately finding the target contour of the exposed graphic, enabling more accurate measurement of the exposed graphic and obtaining a more accurate size. Therefore, when performing OPC modeling based on the size data of the exposed graphic, it is beneficial for more accurate modeling, which in turn is beneficial for optimizing the OPC model and improving predictability. Attached Figure Description

[0032] Figure 1 This is a flowchart of an embodiment of the graphic dimension measurement method of the present invention;

[0033] Figures 2 to 9 This is a schematic diagram of each step in one embodiment of the graphic dimension measurement method of the present invention;

[0034] Figure 10 This is a functional block diagram of an embodiment of the graphic dimension measurement system of the present invention;

[0035] Figure 11 This is a hardware structure diagram of an embodiment of the device provided by the present invention. Detailed Implementation

[0036] As the background technology indicates, the traditional OPC model sample measurement method uses a critical-size scanning electron microscope (CD-SEM) supported by a design gauge. CD-SEM measurements have several limitations. First, due to the scanning mode of CD-SEM, there is a difference between the parallel and perpendicular scanning directions. To obtain the correct width and length of the feature dimensions, two measurements need to be performed on the chip, one of which requires rotating the wafer by 90 degrees. Second, while CD-SEM provides reliable measurements with high accuracy and precision for one-dimensional features, it faces challenges when handling complex features and multi-point measurements. For complex structures, it is difficult to determine what to measure and how to design an appropriate measurement setup to obtain the required data. Finally, how to perform stable measurements in the correct location and capture asymmetries is also a challenge of CD-SEM measurements.

[0037] However, as design rules shrink and process windows become smaller, two-dimensional features become crucial and increasingly important for optimizing OPC models and improving predictability.

[0038] To address the aforementioned technical problems, embodiments of the present invention provide a method for measuring graphic dimensions. (See reference...) Figure 1 The flowchart of an embodiment of the graphic dimension measurement method of the present invention is shown.

[0039] In this embodiment, the graphic size measurement method includes the following basic steps:

[0040] Step S1: Provide the design layout, including multiple design graphics;

[0041] Step S2: Obtain an image of the actual exposure structure corresponding to the design layout. The image includes multiple exposure patterns.

[0042] Step S3: Align the exposure pattern in the image with the corresponding design pattern in the design layout to obtain the alignment position of the image in the design layout;

[0043] Step S4: Based on the alignment position, and in conjunction with the design layout and image, obtain the target outline of the exposure graphic in the image;

[0044] Step S5: Obtain the size of the exposure pattern through the target contour.

[0045] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Figures 2 to 9 This is a schematic diagram of each step in one embodiment of the layout design method of the present invention.

[0047] refer to Figure 2 Step S1: Provide a design layout 100, including multiple design graphics 110.

[0048] The design pattern 200 of the design layout 100 is the pattern to be transferred onto the wafer. After optical proximity correction is performed on the design pattern 110 of the design layout 100, the obtained pattern is used to make a mask, and then the photolithography process is performed using the mask to form the corresponding mask pattern on the wafer.

[0049] Continue to refer to Figure 2 Step S2: Obtain an image 200 of the actual exposure structure corresponding to the design layout 100. The image 200 includes multiple exposure patterns 210.

[0050] The exposure pattern 210 is the pattern of the after-development inspection (ADI) corresponding to the design pattern 110. That is, after the design layout 100 is exposed and developed and transferred to the wafer to form the actual exposure structure, the exposure pattern 210 is obtained by image acquisition of the actual exposure structure.

[0051] In this embodiment, an image 200 of the actual exposure structure corresponding to the design layout 100 is obtained. The image 200 includes multiple exposure patterns 210, including: using electron beam scanning to acquire an image of the actual exposure structure to obtain the image 200 of the actual exposure structure.

[0052] Electron beam scanning can be used to perform relatively efficient and accurate scanning, thereby obtaining relatively clear images 200.

[0053] Specifically, in this embodiment, an eP5 device is used for electron beam scanning to obtain an image 200 of the actual exposed structure. The eP5 has the characteristics of a large field of view (FOV), high speed, and high precision. When using image data acquired by the eP5 for OPC modeling, it is beneficial to shorten the massive data acquisition cycle required for OPC modeling. Moreover, the eP5 supports rotating scanning direction, so there is no need to take two images for the horizontal and vertical directions. Taking one image can simultaneously ensure the graphic size accuracy in the horizontal and vertical directions, thereby reducing the number of images required by the eP5. Furthermore, the acquired image 200 can ensure the dimensional accuracy in the horizontal and vertical directions, which is crucial for accurate modeling.

[0054] In this embodiment, electron beam scanning is used to acquire an image of the actual exposed structure, resulting in an image 200 of the actual exposed structure. This includes: a scanning region A (e.g., ...) set in the actual exposed structure. Figure 2 (a) is shown.

[0055] The scanning area A in the actual exposure structure is set to determine the scanning area A of the wafer in preparation for scanning.

[0056] In this embodiment, the scanning position in scanning area A is determined (e.g., Figure 2 (b) is shown.

[0057] Figure 2 The black dot in (b) is the determined scanning position, which is used to prepare for scanning.

[0058] In this embodiment, the scanning field of view for electron beam scanning is set.

[0059] Based on the requirements of image acquisition, the scanning field of view for electron beam scanning is set to prepare for scanning.

[0060] In this embodiment, the actual exposed structure is image acquired based on the scanning area A, the scanning position, and the scanning field of view.

[0061] Specifically, based on the scanning area A, the scanning position, and the scanning field of view, the area of ​​the scanning position in the design layout (such as...) Figure 2 (c) The actual exposure structure corresponding to the image is acquired to obtain image 200 (as shown). Figure 2 (d) is shown.

[0062] Reference Figures 3 to 6 Step S3: Align the exposure pattern 210 in image 200 with the corresponding design pattern 110 in design layout 100 to obtain the alignment position of image 200 in design layout 100.

[0063] The alignment position of image 200 in design layout 100 is obtained to prepare for obtaining the target outline of exposed graphic 210 in image 200 at the alignment position.

[0064] In this embodiment, the alignment position of image 200 in design layout 100 is obtained by aligning the exposure pattern 210 in image 200 with the corresponding design pattern 110 in design layout 100, including: extracting the initial outline 220 of exposure pattern 210 in image 200.

[0065] Extract the initial outline 220 of the exposure pattern 210 in image 200, and then find the alignment position of image 200 in design layout 100 based on the initial outline 220.

[0066] refer to Figure 3 Extracting the initial contour 220 of the exposure pattern 210 in the image 200 includes: obtaining the grayscale distribution of the image 200, wherein the grayscale distribution includes the grayscale level corresponding to each point in the image 200.

[0067] Image 200, obtained by acquiring an image of the actual exposure structure, is a grayscale image. The edges of the exposure pattern 210 are highlighted, and the edges are usually white. The white edges can be extracted by judging the grayscale level of image 200.

[0068] As an example, such as Figure 3 (b) illustrates the grayscale distribution of an image 200, specifically, Figure 3 (b) is Figure 3 In (a), the grayscale distribution at point aa is represented by the relative position on the horizontal axis and the grayscale level on the vertical axis. In the grayscale distribution, the grayscale level represents the pixel brightness, and its value range is usually from 0 (black) to 255 (white). Thus, the edge of the prominent exposure pattern 210 can be selected as the initial outline 220 by using the grayscale level.

[0069] refer to Figure 4 Before extracting the positions of points in image 200 whose gray levels are higher than a preset threshold as the initial contour 220, the process also includes: performing a first smoothing process on the gray level distribution of image 200.

[0070] The grayscale distribution of image 200 is first smoothed to filter out the effective signal, which helps to reduce the influence of noise and improve the accuracy of subsequent extraction of the initial contour 220 based on the grayscale distribution.

[0071] In this embodiment, a first Gaussian filter is used to perform a first smoothing process on the grayscale distribution of image 200.

[0072] By applying a first Gaussian filter to smooth the grayscale distribution of image 200, noise filtering of the grayscale distribution of image 200 can be effectively achieved.

[0073] Specifically, in this embodiment, during the first smoothing process of the grayscale distribution of image 200 using a first Gaussian filter, the expression is used. Perform the first smoothing process, where (x,y) are the coordinates of the point corresponding to the gray level, and ρ is the first preset parameter.

[0074] As an example, in this embodiment, ρ is 2.

[0075] In this embodiment, the positions of points with gray levels higher than a preset threshold in the image 200 are extracted as the initial contour 220.

[0076] The edges of the exposure pattern 210 will be highlighted, and the edges will usually appear white, meaning that the gray level of the edges of the exposure pattern 210 is high. Therefore, points with a gray level higher than a preset threshold can be used as the initial outline 220 of the exposure pattern 210.

[0077] Accordingly, in this embodiment, the positions of points in image 200 corresponding to gray levels higher than a preset threshold are extracted as the initial contour 220. In the gray distribution after the first smoothing process, the positions of points in image 200 corresponding to gray levels higher than a preset threshold are extracted as the initial contour 220.

[0078] In the grayscale distribution after the first smoothing process, the positions of points with grayscale levels higher than a preset threshold in the image 200 are extracted as the initial contour 220, which helps to improve the efficiency and accuracy of obtaining the initial contour 220.

[0079] refer to Figure 5 By aligning the initial outline 220 with the corresponding design graphic 110, the alignment position of the image 200 in the design layout 100 is obtained.

[0080] The initial outline 220 can preliminarily determine the position of the exposure pattern 210, so that the initial outline 220 of the exposure pattern 210 can be aligned with the design pattern 110 corresponding to the exposure pattern 210 to obtain the alignment position of the image 200 in the design layout 100.

[0081] It should be noted that, for the sake of clarity of the illustration, Figure 5 Only the initial outline 220 is shown; the exposure pattern 200 is not shown.

[0082] In this embodiment, the alignment position of image 200 in design layout 100 is obtained by aligning the initial outline 220 with the corresponding design graphic 110, including: overlapping image 200 with the corresponding area in design layout 100.

[0083] By overlaying the image 200 with the corresponding area in the design layout 100, the corresponding position of the exposed pattern 210 in the image 200 can be found in the design layout 100.

[0084] In this embodiment, overlapping the image 200 with the corresponding area in the design layout 100 includes: setting a portion of the area corresponding to the image 200 in the design layout 100 as a limited area.

[0085] A portion of the area corresponding to image 200 in the design layout 100 is defined as a limited area to preliminarily determine the approximate range of the corresponding position of image 200 in the design layout 100.

[0086] In this embodiment, image 200 is overlaid onto a defined area of ​​design layout 100.

[0087] Image 200 is overlaid onto the defined area of ​​design layout 100 to find the alignment position between exposure pattern 210 and corresponding design pattern 110 through the overlap.

[0088] In this embodiment, the corresponding coordinates between the image 200 and the design layout 100 are aligned so that the image 200 is superimposed on the defined area of ​​the design layout 100.

[0089] Specifically, the origin of image 200 is aligned with the origin of the corresponding area of ​​design layout 100 so that image 200 is superimposed on the defined area of ​​design layout 100.

[0090] In this embodiment, based on the edge of the design pattern 110 corresponding to the exposure pattern 210, an edge extension region 120 is generated inside and outside the design pattern 110 to surround and cover the edge of the design pattern 110.

[0091] Generating an edge extension region 120 that surrounds and covers the edges of the design graphic 110 inside and outside the design graphic 110 means that the edge extension region 120 surrounds the design graphic 110 and simultaneously covers the area inside and outside the design graphic 110.

[0092] An edge extension region 120 is produced to align with the initial outline 220. Since the initial outline 220 is a region and the edge of the design graphic 110 is a line, a region of the edge extension region 120 needs to be generated based on the edge in order to find the alignment position by aligning the regions.

[0093] In this embodiment, when the overlap rate between the initial contour 220 and the edge extension region 120 is maximized, the relative position of the image 200 in the design layout 100 is used as the alignment position.

[0094] When the overlap rate between the initial outline 220 and the edge extension area 120 is at its maximum, it indicates that the exposed pattern 200 and the corresponding design pattern 100 are most aligned at this time. Thus, the relative position of the image 200 in the design layout 100 at this time is used as the alignment position.

[0095] Specifically, in this embodiment, when the overlap rate between the initial contour 220 and the edge extension region 120 is maximized, the relative position of the image 200 in the design layout 100 is used as the alignment position, including setting the search step size.

[0096] The search step size is the displacement of the image by 200 units each time it moves within a defined area.

[0097] In this embodiment, multiple search processes are performed in a defined area. The search processes include: moving the image 200 to the search position based on the search step size; and obtaining the ratio of the total overlapping area of ​​the initial contour 220 and the edge extension region 120 in the image 200 at the search position to the total area of ​​the edge extension region 120 as the overlap rate.

[0098] Multiple search processes are performed, and the ratio of the total overlapping area of ​​the initial contour 220 and the edge extension region 120 in the image 200 to the total area of ​​the edge extension region 120 is compared at each search position. When this ratio is the largest, it indicates that the search position is the position where the image 200 and the design layout 100 are most aligned during the multiple search processes.

[0099] Specifically, in this embodiment, the expression is used. Calculate the overlap ratio for each search location, where Overlap_ratio is the overlap ratio, Overlay area is the total area of ​​overlap between the initial contour 220 and the edge extension region 120 in image 200, and Expansion_region area is the total area of ​​the edge extension region 120 in image 200.

[0100] Accordingly, the search position corresponding to the maximum overlap rate is obtained as the alignment position.

[0101] Reference Figure 6 and Figure 7 Step S4: Based on the alignment position, and combining the design layout 100 and the image 200, obtain the target outline 230 of the exposure pattern 210 in the image 200.

[0102] The target contour 230 is used for subsequent dimensional measurements of the exposure pattern 200.

[0103] In this embodiment, the alignment position of image 200 in design layout 100 is first obtained. Then, based on the alignment position, and combined with design layout 100 and image 200, the target contour 230 of exposure pattern 210 in image 200 is obtained. This helps to more accurately find the target contour 230 of exposure pattern 200, enabling more accurate measurement of exposure pattern 200 and obtaining more accurate dimensions. Therefore, when performing OPC modeling based on the size data of exposure pattern 200, it is beneficial to more accurate modeling, which in turn helps to optimize the OPC model and improve predictability.

[0104] In this embodiment, based on the alignment position, and combining the design layout 100 and the image 200, the target contour 230 of the exposure pattern 210 in the image 200 is obtained, including: overlapping the image 200 with the design layout 100 at the alignment position.

[0105] The image 200 is overlapped with the design layout 100 at the alignment position to place the image 200 in the accurate position in the design layout 100, so that subsequent calculations based on it are more accurate.

[0106] In this embodiment, the grayscale distribution of image 200 is obtained, and the grayscale distribution includes the grayscale level corresponding to each point in image 200.

[0107] As an example, such as Figure 6 (b) illustrates the grayscale distribution of an image 200, specifically, Figure 6 (b) is Figure 6 In (a), the grayscale distribution at point bb is represented by the horizontal axis as the relative position and the vertical axis as the grayscale level. In the grayscale distribution, the grayscale level represents the pixel brightness, and its value range is usually from 0 (black) to 255 (white).

[0108] In this embodiment, before selecting the point corresponding to the gray level equal to a preset threshold as the target edge point based on the position of the edge mapping of the design graphic 110 in the image 200, the method further includes: using the area mapped by the edge extension region 120 in the image 200 as the detection area (corresponding to the area in the image 200). Figure 6 (b) is the area within the box.

[0109] Using the area mapped by the edge extension region 120 in the image 200 as the detection area is beneficial for subsequent targeted calculations in the detection area, reducing computing power and also reducing noise interference.

[0110] In this embodiment, before selecting the point corresponding to the gray level equal to the preset threshold as the target edge point based on the position of the edge mapping of the design graphic 110 in the image 200, the method further includes: performing a second smoothing process on the gray level distribution of the image 200.

[0111] A second smoothing process is applied to the grayscale distribution of image 200 to filter out the effective signal and enhance the effective signal. This helps to reduce the influence of noise and improve the accuracy of subsequent extraction of target edge points based on the grayscale distribution.

[0112] In this embodiment, a second Gaussian filter is used to perform a second smoothing process on the grayscale distribution of image 200.

[0113] By employing a second Gaussian filter to perform a second smoothing process on the grayscale distribution of image 200, noise filtering of the grayscale distribution of image 200 can be effectively achieved.

[0114] Specifically, in this embodiment, during the second smoothing process of the grayscale distribution of image 200 using a second Gaussian filter, the expression is used. A second smoothing process is performed, where (x,y) are the coordinates of the point corresponding to the gray level, σ1 is the second preset parameter, and ρ2 is the third preset parameter.

[0115] In this embodiment, based on the position of the edge mapping of the design graphic 110 in the image 200, the point corresponding to the gray level equal to the preset threshold is selected as the target edge point.

[0116] Points with gray levels equal to a preset threshold are selected as target edge points. Based on the characteristic that the edges of the exposure pattern 210 have high gray levels, a preset threshold is set to select points with gray levels equal to the preset threshold as target edge points.

[0117] In this embodiment, based on the position of the edge mapping of the design graphic 110 in the image 200, the points corresponding to the gray level equal to the preset threshold are selected as edge points, including: selecting the points corresponding to the gray level equal to the preset threshold in the detection area as initial edge points.

[0118] like Figure 6 As shown, the box area corresponds to the detection area, and the dashed line corresponds to the preset threshold. In the box area, the intersection of the dashed line and the grayscale distribution curve is the initial edge point.

[0119] The initial edge points are used as a reference for obtaining the target edge points later.

[0120] Specifically, in this embodiment, when there is an initial edge point in the detection area, the initial edge point is selected as the target edge point in the extension direction perpendicular to the detection area.

[0121] In the direction perpendicular to the extension of the detection area, there is an initial edge point in the detection area, that is, in Figure 6 In the boxed area in (b), there is only one intersection point. In this case, the point in image 200 corresponding to the intersection point is selected as the target edge point.

[0122] In this embodiment, when there are two initial edge points in the detection area, one of the initial edge points is selected as the target edge point in the extension direction perpendicular to the detection area.

[0123] In the direction perpendicular to the extension of the detection area, there are two initial edge points in the detection area, namely... Figure 6 In the boxed area in (b), there are two intersection points. In this case, one of the initial edge points is selected as the target edge point.

[0124] In this embodiment, when there are two initial edge points in the detection area, selecting one of the initial edge points as the target edge point includes: determining that the exposure pattern 210 corresponding to the detection area is suitable for measuring the structural size or suitable for measuring the structural interval.

[0125] The exposure pattern 210 corresponding to the detection area is determined to be suitable for measuring the structural dimensions or the structural intervals, and the target edge point is selected according to the measurement target.

[0126] Specifically, in this embodiment, when the exposure pattern 210 corresponding to the detection area is suitable for measuring the structural dimension (line), an initial edge point that is far from the interior of the corresponding design pattern 110 in the extension direction perpendicular to the detection area is selected as the target edge point; when the exposure pattern 210 corresponding to the detection area is suitable for measuring the structural space, an initial edge point that is close to the interior of the corresponding design pattern 110 in the extension direction perpendicular to the detection area is selected as the target edge point.

[0127] As an example, Figure 6 If there is only one intersection point in the left box of (b), then the point corresponding to that intersection point (as shown in the circle) in image 200 is selected as the target edge point. Figure 6 (b) There are two intersection points in the right box. The exposure pattern 210 is suitable for measuring the structural interval. Then, the point in image 200 corresponding to the initial edge point close to the interior of the corresponding design pattern 110, i.e., the left intersection point (as shown in the circle), is selected as the target edge point.

[0128] refer to Figure 7 Connect multiple target edge points to form the target outline 230.

[0129] In this embodiment, multiple target edge points are connected to form a target contour 230. By combining multiple target edge points, edge fitting is performed to obtain the target contour.

[0130] In this embodiment, when connecting multiple target edge points, edge fitting is performed at the locations where the signal is missing in order to obtain a more accurate target contour 230.

[0131] refer to Figure 8 Before obtaining the size of the exposure pattern 210 through the target outline 230, the method further includes: overlapping the image 200 with the design layout 100 at the alignment position.

[0132] Image 200 is aligned with design layout 100 to prepare for further adjustments to the target outline 230.

[0133] In this embodiment, the edge placement error between each edge of each target contour 230 in the image 200 and the corresponding design graphic 110 is calculated.

[0134] The edge position error (EPE) between each edge of each target contour 230 in image 200 and the corresponding design pattern 110 is calculated. The edge position error refers to the deviation between the photoresist pattern edge and the design pattern after exposure during the photolithography process. In other words, the edge position error characterizes the error between the target contour 230 and the design pattern 110. The target contour 230 is then adjusted by the edge position error to make the target contour 230 more accurate.

[0135] Accordingly, in this embodiment, the target contour 230 is adjusted based on the edge placement error.

[0136] In this embodiment, adjusting the target contour 230 based on edge placement error includes: acquiring the horizontal direction (e.g., in the image 200) of each target contour 230. Figure 8 Half of the average difference in edge placement error between opposite sides extending in the X direction (as shown in the middle) is taken as the first adjustment value.

[0137] Specifically, in this embodiment, an expression is used. Calculate the first adjustment value, where Y shift As the first adjustment value, top and bottom are the relative top and bottom edges of each target contour 230 extending horizontally, respectively, EPE. top Errors are placed on the upper edge of each target contour 230. EPE represents the average edge placement error of all target contours 230. bottom For each target contour, place an error at the lower edge of 230. The average value representing the edge placement error of the entire target contour 230 is therefore... In the characterization image 200, half of the average difference in edge placement error between opposite sides of each target contour 230 extending in the horizontal direction is used to adjust the vertical position of the target contour 230 as a whole using a first adjustment value. Therefore, half of the average difference in edge placement error between opposite sides of each target contour 230 extending in the horizontal direction is used as the first adjustment value.

[0138] In this embodiment, each target contour 230 in the acquired image is along the vertical direction (e.g., Figure 8 The second adjustment value is half the average difference of the edge placement errors of the opposite sides extending in the Y direction (as shown in the middle).

[0139] Specifically, in this embodiment, an expression is used. Calculate the first adjustment value, where X shift For the second adjustment value, right and left are the opposite right and left sides of each target contour 230 extending vertically, respectively, EPE.right An error is placed on the right edge of each target contour 230. EPE represents the average edge placement error to the right of all target contours 230. left An error is placed on the left edge of each target contour 230. The average value representing the placement error of the left edge of the entire target contour 230 is therefore... In the characterization image 200, half of the average difference in edge placement error between opposite sides of each target contour 230 extending in the vertical direction is used to adjust the horizontal position of the target contour 230 as a whole. Therefore, half of the average difference in edge placement error between opposite sides of each target contour 230 extending in the vertical direction is used as the second adjustment value.

[0140] In this embodiment, each target contour 230 is shifted vertically by the absolute value of the first adjustment value in the opposite direction.

[0141] The distance by which the absolute value of the first adjustment value is translated in the opposite direction to the first adjustment value refers to the distance by which each target contour 230 is translated along the negative direction of the Y direction to the absolute value of the first adjustment when the first adjustment value is positive (i.e., representing the positive direction of the Y direction), and the distance by which each target contour 230 is translated along the positive direction of the Y direction to the absolute value of the first adjustment when the first adjustment value is negative (i.e., representing the negative direction of the Y direction).

[0142] In this embodiment, each target contour 230 is shifted horizontally by the absolute value of the second adjustment value in the opposite direction.

[0143] The distance by which the absolute value of the second adjustment value is translated in the opposite direction to the second adjustment value refers to the distance by which each target contour 230 is translated along the negative direction of the X direction to the absolute value of the first adjustment when the second adjustment value is positive (i.e., representing the positive direction of the X direction), and the distance by which each target contour 230 is translated along the positive direction of the X direction to the absolute value of the first adjustment when the second adjustment value is negative (i.e., representing the negative direction of the X direction).

[0144] refer to Figure 9 Step S5: Obtain the size of the exposure pattern 210 through the target contour 230.

[0145] Specifically, in this embodiment, obtaining the size of the exposure pattern 210 through the target contour 230 includes: defining measurement marks on the image 200; and performing measurements at the locations of the measurement marks.

[0146] As an example, Figure 9 (a) Define the measurement mark (as shown by the short vertical line in the figure) for the graphic width (CD). Measure the graphic width at the measurement mark. Figure 9 (b) Define the graphic interval (space) using measurement markers (as shown by the vertical lines in the figure). Measure the graphic interval at these markers. Figure 9 (c) Length Definition: Measurement marks (as shown by the straight lines parallel to and spanning the figure in the diagram) are used to measure the length of the figure. Figure 9 (c) Head-to-Head (HTH) Definition of measurement marks (as shown by the parallel straight lines that span the interval between the ends of the figures in the figure), at which the head-to-head of the figures is measured.

[0147] In this embodiment, after defining measurement marks on image 200, a size file containing the coordinates of all measurement marks and measurement data can be output, realizing the automation of contour measurement, improving measurement efficiency and accuracy. Moreover, users can choose a suitable method to perform contour measurement according to their own needs and obtain the required size data. It has wide application value in applications such as optical proximity correction (OPC) modeling, and can help users analyze and optimize the manufacturing process more accurately.

[0148] In other embodiments, obtaining the size of the exposed pattern through the target contour may further include: providing a size file, including coordinates corresponding to the image and measurement types corresponding to the coordinates; and obtaining measurement results of the image based on the size file.

[0149] Accordingly, the present invention also provides a graphic dimension measurement system. Figure 10 This is a functional block diagram of an embodiment of the graphic dimension measurement system of the present invention.

[0150] In this embodiment, the graphic size measurement system 50 includes: a design layout providing module 501, used to provide a design layout, including multiple design graphics; an image acquisition module 502, used to acquire an image of the actual exposure structure corresponding to the design layout, the image including multiple exposure graphics; an image alignment module 503, used to obtain the alignment position of the image in the design layout by aligning the exposure graphics in the image with the corresponding design graphics in the design layout; a target contour acquisition module 504, used to obtain the target contour of the exposure graphics in the image based on the alignment position, combined with the design layout and the image; and a measurement module 505, used to obtain the size of the exposure graphics through the target contour.

[0151] Design layout provider module 501 is used to provide design layouts, including multiple design graphics.

[0152] The design pattern of the design layout is the pattern that needs to be transferred onto the wafer. After optical proximity correction is performed on the design pattern of the design layout, the resulting pattern is used to create a photomask, which is then used for photolithography to form the corresponding mask pattern on the wafer.

[0153] The image acquisition module 502 is used to acquire an image of the actual exposure structure corresponding to the design layout. The image includes multiple exposure patterns.

[0154] The exposure pattern is the pattern obtained after development inspection (ADI) corresponding to the design pattern. That is, after the design pattern is exposed and developed and transferred to the wafer to form the actual exposure structure, the exposure pattern is obtained by image acquisition of the actual exposure structure.

[0155] In this embodiment, an image of the actual exposure structure corresponding to the design layout is obtained. The image includes multiple exposure patterns, including: using electron beam scanning to acquire an image of the actual exposure structure to obtain an image of the actual exposure structure.

[0156] Electron beam scanning can be used to perform relatively efficient and accurate scanning, thereby obtaining clearer images.

[0157] Specifically, in this embodiment, an eP5 device is used for electron beam scanning to obtain an image of the actual exposed structure. The eP5 has the characteristics of a large field of view (FOV), high speed, and high precision. When using image data acquired by the eP5 for OPC modeling, it is beneficial to shorten the massive data acquisition cycle required for OPC modeling. Moreover, the eP5 supports rotating scanning direction, so there is no need to take two images for the horizontal and vertical directions. Taking one image can simultaneously ensure the graphic size accuracy in both the horizontal and vertical directions, thereby reducing the number of images required by the eP5. Furthermore, the acquired images can ensure the dimensional accuracy in both the horizontal and vertical directions, which is crucial for accurate modeling.

[0158] In this embodiment, an image of the actual exposure structure is acquired by electron beam scanning, including a scanning area A set in the actual exposure structure.

[0159] The scanning area A in the actual exposure structure is set to determine the scanning area A of the wafer in preparation for scanning.

[0160] In this embodiment, the scanning position in scanning area A is determined.

[0161] The designated scanning location is used to prepare for the scan.

[0162] In this embodiment, the scanning field of view for electron beam scanning is set.

[0163] Based on the requirements of image acquisition, the scanning field of view for electron beam scanning is set to prepare for scanning.

[0164] In this embodiment, the actual exposed structure is image acquired based on the scanning area A, the scanning position, and the scanning field of view.

[0165] Specifically, based on the scanning area A, the scanning position, and the scanning field of view, the actual exposure structure corresponding to the scanning position in the design layout is image acquired to obtain an image.

[0166] The image alignment module 503 is used to obtain the alignment position of the image in the design layout by aligning the exposure pattern in the image with the corresponding design pattern in the design layout.

[0167] Obtain the alignment position of the image in the design layout to prepare for obtaining the target outline of the exposed graphic in the image at the alignment position.

[0168] In this embodiment, the alignment position of the image in the design layout is obtained by aligning the exposure pattern in the image with the corresponding design pattern in the design layout, including: extracting the initial outline of the exposure pattern in the image.

[0169] Extract the initial outline of the exposed graphic in the image, and then find the alignment position of the image in the design layout based on the initial outline.

[0170] In this embodiment, extracting the initial contour of the exposed pattern in the image includes: obtaining the grayscale distribution of the image, whereby the grayscale distribution includes the grayscale level corresponding to each point in the image.

[0171] The image obtained by acquiring the actual exposure structure is a grayscale image. In this image, the edges of the exposure pattern will be highlighted, and the edges will usually appear white. Therefore, the white edges can be extracted by judging the grayscale level of the image.

[0172] As an example, such as Figure 3 (b) illustrates a grayscale distribution of an image, specifically, Figure 3 (b) is Figure 3 In (a), the grayscale distribution at point aa is represented by the relative position on the horizontal axis and the grayscale intensity on the vertical axis. In the grayscale distribution, the grayscale intensity represents the pixel brightness, and its value range is usually from 0 (black) to 255 (white). Thus, the edge of the prominent exposure pattern can be selected as the initial outline by using the grayscale intensity.

[0173] In this embodiment, before extracting the positions of points in the image whose gray levels are higher than a preset threshold as the initial contour, the method further includes: performing a first smoothing process on the gray level distribution of the image.

[0174] Performing a first smoothing process on the grayscale distribution of the image filters out the effective signal, which helps to reduce the influence of noise and improve the accuracy of subsequent extraction of the initial contour based on the grayscale distribution.

[0175] In this embodiment, a first Gaussian filter is used to perform a first smoothing process on the grayscale distribution of the image.

[0176] Applying a first Gaussian filter to smooth the grayscale distribution of an image can effectively filter out noise in the grayscale distribution.

[0177] Specifically, in this embodiment, during the first smoothing process of the image's grayscale distribution using a first Gaussian filter, the expression is used. Perform the first smoothing process, where (x,y) are the coordinates of the point corresponding to the gray level, and ρ is the first preset parameter.

[0178] As an example, in this embodiment, σ is 2.

[0179] In this embodiment, the positions of points in the image corresponding to gray levels higher than a preset threshold are extracted as the initial contour.

[0180] The edges of the exposed pattern will be highlighted, and the edges will usually appear white, meaning that the gray level of the edges of the exposed pattern is high. Therefore, points with a gray level higher than the preset threshold can be used as the initial outline of the exposed pattern.

[0181] Accordingly, in this embodiment, the positions of points in the image corresponding to gray levels higher than a preset threshold are extracted as the initial contour. In the gray distribution after the first smoothing process, the positions of points in the image corresponding to gray levels higher than the preset threshold are extracted as the initial contour.

[0182] In the grayscale distribution after the first smoothing process, the positions of points with grayscale levels higher than a preset threshold in the image are extracted as the initial contours, which helps to improve the efficiency and accuracy of obtaining the initial contours.

[0183] In this embodiment, the alignment position of the image in the design layout is obtained by aligning the initial outline with the corresponding design graphic.

[0184] The initial outline can preliminarily determine the position of the exposed graphic, so that the initial outline of the exposed graphic can be aligned with the corresponding design graphic to obtain the alignment position of the image in the design layout.

[0185] In this embodiment, the alignment position of the image in the design layout is obtained by aligning the initial outline with the corresponding design graphic, including: overlapping the image with the corresponding area in the design layout.

[0186] By overlaying the image with the corresponding area in the design layout, it is possible to find the corresponding position of the exposed graphic in the image within the design layout.

[0187] In this embodiment, overlapping the image with the corresponding area in the design layout includes: setting a portion of the area corresponding to the image in the design layout as a limited area.

[0188] Define a limited area corresponding to the image in the design layout as a preliminary range for determining the approximate location of the image in the design layout.

[0189] In this embodiment, the image is overlaid onto a defined area of ​​the design layout.

[0190] The image is overlaid onto a defined area of ​​the design layout to determine the alignment between the exposed graphic and the corresponding design graphic through the overlap.

[0191] In this embodiment, the corresponding coordinates between the image and the design layout are aligned so that the image is overlaid onto the defined area of ​​the design layout.

[0192] Specifically, the origin of the image is aligned with the origin of the corresponding area of ​​the design layout to overlay the image onto the defined area of ​​the design layout.

[0193] In this embodiment, based on the edge of the design graphic corresponding to the exposure graphic, an edge extension region is generated inside and outside the design graphic to surround and cover the edge of the design graphic.

[0194] Generating an edge extension region that surrounds and covers the edges of the design graphic means that the edge extension region surrounds the design graphic and simultaneously covers the areas inside and outside the design graphic.

[0195] The edge extension region is generated to align with the initial outline. The initial outline is a region, while the edges of the design are lines. Therefore, an edge extension region needs to be generated based on the edges in order to find the alignment position by aligning the regions.

[0196] In this embodiment, the relative position of the image in the design layout is used as the alignment position when the overlap rate between the initial contour and the edge extension area is maximized.

[0197] When the overlap rate between the initial outline and the edge extension area is at its maximum, it indicates that the exposed graphic and the corresponding design graphic are most aligned. Therefore, the relative position of the image in the design layout at this time is used as the alignment position.

[0198] Specifically, in this embodiment, when the overlap rate between the initial contour and the edge extension area is maximized, the relative position of the image in the design layout is used as the alignment position, including setting the search step size.

[0199] The search step size is the displacement of the image each time it is moved within a defined area.

[0200] In this embodiment, multiple search processes are performed within a defined area. The search processes include: moving the image to the search position based on the search step size; and obtaining the ratio of the total overlapping area of ​​the initial contour and the edge extension area to the total area of ​​the edge extension area in the image at the search position as the overlap rate.

[0201] Perform multiple search processes and compare the ratio of the total overlapping area of ​​the initial contour and the edge extension area to the total area of ​​the edge extension area in the image at each search location. When this ratio is the largest, it indicates that the search location is the one where the image and the design layout are most aligned during the multiple search processes.

[0202] Specifically, in this embodiment, the expression is used. Calculate the overlap ratio for each search location, where Overlap_ratio is the overlap ratio, Overlay area is the total area of ​​overlap between the initial contour and the edge extension region in the image, and Expansion_region area is the total area of ​​the edge extension region in the image.

[0203] Accordingly, the search position corresponding to the maximum overlap rate is obtained as the alignment position.

[0204] The target contour acquisition module 504 is used to acquire the target contour of the exposure pattern in the image based on the alignment position, combined with the design layout and the image.

[0205] The target profile is used for subsequent dimensional measurements of the exposure pattern.

[0206] In this embodiment, the alignment position of the image in the design layout is first obtained. Then, based on the alignment position, the target contour of the exposure graphic in the image is obtained by combining the design layout and the image. This helps to find the target contour of the exposure graphic more accurately, so that the exposure graphic can be measured more accurately and the size can be obtained more accurately. Therefore, when performing OPC modeling based on the size data of the exposure graphic, it is beneficial to model more accurately, which in turn helps to optimize the OPC model and improve predictability.

[0207] In this embodiment, based on the alignment position, combined with the design layout and the image, the target outline of the exposure pattern in the image is obtained, including: overlapping the image with the design layout at the alignment position.

[0208] Overlay the image with the design layout at the alignment point to place the image in the accurate position on the design layout, so that subsequent calculations based on it are more accurate.

[0209] In this embodiment, the grayscale distribution of the image is obtained, which includes the grayscale level corresponding to each point in the image.

[0210] As an example, such as Figure 6(b) illustrates a grayscale distribution of an image, specifically, Figure 6 (b) is Figure 6 In (a), the grayscale distribution at point bb is represented by the horizontal axis as the relative position and the vertical axis as the grayscale level. In the grayscale distribution, the grayscale level represents the pixel brightness, and its value range is usually from 0 (black) to 255 (white).

[0211] In this embodiment, before selecting the point corresponding to the gray level equal to the preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, it further includes: using the area mapped by the edge extension region in the image as the detection area.

[0212] Using the region mapped in the image by the edge extension area as the detection area is beneficial for subsequent targeted calculations in the detection area, reducing computing power and also reducing noise interference.

[0213] In this embodiment, before selecting the point corresponding to the gray level equal to the preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, the method further includes: performing a second smoothing process on the gray level distribution of the image.

[0214] A second smoothing process is applied to the grayscale distribution of the image to filter out the effective signal and enhance the effective signal. This helps to reduce the influence of noise and improve the accuracy of subsequent extraction of target edge points based on the grayscale distribution.

[0215] In this embodiment, a second Gaussian filter is used to perform a second smoothing process on the grayscale distribution of the image.

[0216] By employing a second Gaussian filter to perform a second smoothing process on the grayscale distribution of the image, noise filtering of the grayscale distribution of the image can be effectively achieved.

[0217] Specifically, in this embodiment, during the second smoothing process of the image's grayscale distribution using a second Gaussian filter, the expression is used. A second smoothing process is performed, where (x,y) are the coordinates of the point corresponding to the gray level, σ1 is the second preset parameter, and σ2 is the third preset parameter.

[0218] In this embodiment, based on the position of the edge mapping of the design graphic in the image, the point corresponding to the gray level equal to the preset threshold is selected as the target edge point.

[0219] Points with gray levels equal to a preset threshold are selected as target edge points. Based on the characteristic that the edges of the exposed image have higher gray levels, a preset threshold is set to select points with gray levels equal to the preset threshold as target edge points.

[0220] In this embodiment, based on the position of the edge mapping of the design graphic in the image, points corresponding to gray levels equal to a preset threshold are selected as edge points, including: selecting points in the detection area corresponding to gray levels equal to a preset threshold as initial edge points.

[0221] The intersection of the preset threshold and the grayscale distribution curve is the initial edge point.

[0222] The initial edge points are used as a reference for obtaining the target edge points later.

[0223] Specifically, in this embodiment, when there is an initial edge point in the detection area, the initial edge point is selected as the target edge point in the extension direction perpendicular to the detection area.

[0224] In the direction perpendicular to the extension of the detection area, there is an initial edge point in the detection area, that is, the detection area has only one intersection point. At this time, the point in the image corresponding to the intersection point is selected as the target edge point.

[0225] In this embodiment, when there are two initial edge points in the detection area, one of the initial edge points is selected as the target edge point in the extension direction perpendicular to the detection area.

[0226] In the direction perpendicular to the extension of the detection area, there are two initial edge points in the detection area, that is, the detection area has two intersection points. At this time, one of the initial edge points is selected as the target edge point.

[0227] In this embodiment, when there are two initial edge points in the detection area, selecting one of the initial edge points as the target edge point includes: determining that the exposure pattern corresponding to the detection area is suitable for measuring the structural size or suitable for measuring the structural interval.

[0228] The system determines whether the exposure pattern corresponding to the detection area is suitable for measuring the structural dimensions or the structural spacing, and then selects the target edge point based on the measurement target.

[0229] Specifically, in this embodiment, when the exposure pattern corresponding to the detection area is suitable for measuring the structural size, an initial edge point that is far from the interior of the corresponding design pattern in the extension direction perpendicular to the detection area is selected as the target edge point; when the exposure pattern corresponding to the detection area is suitable for measuring the structural interval, an initial edge point that is close to the interior of the corresponding design pattern in the extension direction perpendicular to the detection area is selected as the target edge point.

[0230] In this embodiment, multiple target edge points are connected to form the target outline.

[0231] In this embodiment, multiple target edge points are connected to form the target contour. By combining multiple target edge points, edge fitting is performed to obtain the target contour.

[0232] In this embodiment, when connecting multiple target edge points, edge fitting is performed at the locations where the signal is missing in order to obtain a more accurate target contour.

[0233] In this embodiment, before obtaining the size of the exposed pattern through the target contour, the method further includes: overlapping the image with the design layout at the alignment position.

[0234] Overlay the image with the design layout at the alignment point to prepare for further adjustments to the target outline.

[0235] In this embodiment, the edge placement error between each edge of each target contour in the image and the corresponding design graphic is calculated.

[0236] The edge position error (EPE) is calculated between each edge of each target contour in the image and the corresponding design pattern. The edge position error refers to the deviation between the edge of the photoresist pattern and the design pattern after exposure during the photolithography process. In other words, the edge position error characterizes the error between the target contour and the design pattern. The target contour is then adjusted by the edge position error to make the target contour more accurate.

[0237] Accordingly, in this embodiment, the target contour is adjusted based on the edge placement error.

[0238] In this embodiment, adjusting the target contour based on edge placement error includes: obtaining half of the average difference in edge placement error between opposite sides of each target contour extending horizontally in the image, as the first adjustment value.

[0239] Specifically, in this embodiment, an expression is used. Calculate the first adjustment value, where Y shift The first adjustment value is denoted by 'top' and 'bottom', which represent the top and bottom edges of each target contour extending horizontally, respectively. EPE top Errors are placed on the edges of each target contour. EPE represents the average edge placement error of all target contours. bottom Errors are placed at the lower edge of each target contour. The average value representing the edge placement error of the entire target contour is, therefore, The average value of the difference in edge placement error between opposite sides of each target contour extending horizontally in the characterization image is half of the average value. Subsequently, the vertical position of the target contour is adjusted as a whole by the first adjustment value. Therefore, half of the average value of the difference in edge placement error between opposite sides of each target contour extending horizontally is used as the first adjustment value.

[0240] In this embodiment, half of the average difference in edge placement error between opposite sides of each target contour extending vertically in the image is obtained as the second adjustment value.

[0241] Specifically, in this embodiment, an expression is used. Calculate the first adjustment value, where X shift The second adjustment value is 'right', where 'right' and 'left' represent the opposite right and left sides of each target contour extending vertically, respectively. EPE right Place an error on the right edge of each target contour. EPE represents the average edge placement error on the right side of all target contours. left Place an error on the left edge of each target contour. The average value representing the edge placement error on the left side of all target contours, therefore, The average difference in edge placement error between opposite sides of each target contour extending vertically in the characterization image is half of the average difference in edge placement error. Subsequently, the horizontal position of the target contour is adjusted as a whole by a second adjustment value. Therefore, half of the average difference in edge placement error between opposite sides of each target contour extending vertically is used as the second adjustment value.

[0242] In this embodiment, each target contour is shifted vertically by the absolute value of the first adjustment value in the opposite direction.

[0243] The distance by which the absolute value of the first adjustment value is shifted in the opposite direction to the first adjustment value refers to the distance by which each target contour is shifted to the absolute value of the first adjustment in the negative direction of the Y direction when the first adjustment value is positive (i.e., representing the positive direction of the Y direction), and the distance by which each target contour is shifted to the absolute value of the first adjustment in the positive direction of the Y direction when the first adjustment value is negative (i.e., representing the negative direction of the Y direction).

[0244] In this embodiment, each target contour is shifted horizontally by the absolute value of the second adjustment value in the opposite direction.

[0245] The distance of shifting the absolute value of the second adjustment value in the opposite direction to the second adjustment value refers to the distance by which each target contour is shifted to the absolute value of the first adjustment along the negative direction of the X direction when the second adjustment value is positive (i.e., representing the positive direction of the X direction), and the distance by which each target contour is shifted to the absolute value of the first adjustment along the positive direction of the X direction when the second adjustment value is negative (i.e., representing the negative direction of the X direction).

[0246] The measurement module 505 is used to obtain the size of the exposure pattern through the target contour.

[0247] Specifically, in this embodiment, obtaining the size of the exposure pattern through the target contour includes: defining measurement marks on the image; and performing measurements at the locations of the measurement marks.

[0248] In this embodiment, after defining measurement marks on the image, a dimension file containing the coordinates of all measurement marks and measurement data can be output, realizing the automation of contour measurement, improving measurement efficiency and accuracy. Moreover, users can choose a suitable method to perform contour measurement according to their own needs and obtain the required dimension data. It has wide application value in applications such as optical proximity correction (OPC) modeling, and can help users analyze and optimize the manufacturing process more accurately.

[0249] In other embodiments, obtaining the size of the exposed pattern through the target contour may further include: providing a size file, including coordinates corresponding to the image and measurement types corresponding to the coordinates; and obtaining measurement results of the image based on the size file.

[0250] This invention also provides a device that can implement the graphic size measurement method provided in this invention by loading a program, as described above. An optional hardware structure of the terminal device provided in this invention can be as follows: Figure 11 As shown, it includes: at least one processor 01, at least one communication interface 02, at least one memory 03, and at least one communication bus 04.

[0251] In this embodiment, the number of processor 01, communication interface 02, memory 03, and communication bus 04 is at least one, and the processor 01, communication interface 02, and memory 03 communicate with each other through communication bus 04. Communication interface 02 can be an interface of a communication module for network communication, such as the interface of a GSM module. Processor 01 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. Memory 03 may include high-speed RAM and may also include non-volatile memory (NVM), such as at least one disk storage device. Memory 03 stores one or more computer instructions, which are executed by processor 01 to implement the graphic size measurement method provided in this embodiment of the present invention.

[0252] It should be noted that the aforementioned terminal device may also include other devices (not shown) that may not be essential to understanding the content disclosed in the embodiments of the present invention; given that these other devices may not be essential for understanding the content disclosed in the embodiments of the present invention, the embodiments of the present invention will not describe them one by one.

[0253] This invention also provides a storage medium storing one or more computer instructions for implementing the graphic dimension measurement method provided in this invention.

[0254] In this embodiment of the invention, the alignment position of the image in the design layout is first obtained. Then, based on the alignment position, the target contour of the exposed graphic in the image is obtained by combining the design layout and the image. This is beneficial for finding the target contour of the exposed graphic more accurately, so that the exposed graphic can be measured more accurately and the size can be obtained more accurately. Therefore, when performing OPC modeling based on the size data of the exposed graphic, it is beneficial for more accurate modeling, which in turn is beneficial for optimizing the OPC model and improving predictability.

[0255] The embodiments of the present invention described above are combinations of elements and features of the present invention. Unless otherwise stated, the elements or features described are optional. Individual elements or features may be practiced without combination with other elements or features. Furthermore, embodiments of the present invention may be constructed by combining some elements and / or features. The order of operations described in the embodiments of the present invention may be rearranged. Some constructions of any embodiment may be included in another embodiment and may be replaced by corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims in the appended claims that are not expressly referenced to each other may be combined to form embodiments of the present invention, or may be included as new claims in amendments made after the filing of this application.

[0256] Embodiments of the present invention can be implemented by various means, such as hardware, firmware, software, or combinations thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc. In a firmware or software configuration, embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. Software code can be stored in memory units and executed by a processor. The memory units are located inside or outside the processor and can send data to and receive data from the processor via various known means.

[0257] This invention also provides a computer program product, including computer programs / instructions, which, when executed by a processor, implement the graphic size measurement method provided in this invention.

[0258] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is accorded the widest scope consistent with the principles and novel features disclosed herein.

[0259] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for measuring the dimensions of a graphic, characterized in that, include: Provides a design layout, including multiple design graphics; Obtain an image of the actual exposure structure corresponding to the design layout, the image including multiple exposure patterns; The alignment position of the image in the design layout is obtained by aligning the exposure pattern in the image with the corresponding design pattern in the design layout. Based on the alignment position, and in conjunction with the design layout and the image, the target outline of the exposure pattern in the image is obtained; The size of the exposure pattern is obtained by using the target contour.

2. The graphic dimension measurement method as described in claim 1, characterized in that, Obtain an image of the actual exposure structure corresponding to the design layout. The image includes multiple exposure patterns, including: acquiring an image of the actual exposure structure using electron beam scanning to obtain an image of the actual exposure structure.

3. The graphic dimension measurement method as described in claim 2, characterized in that, Image acquisition of the actual exposure structure using electron beam scanning to obtain an image of the actual exposure structure includes: setting a scanning area in the actual exposure structure; Determine the scanning position within the scanning area; Set the scanning field of view for the electron beam scanning; Based on the scanning area, scanning position, and scanning field of view, an image is acquired of the actual exposed structure.

4. The graphic dimension measurement method as described in claim 1, characterized in that, The alignment position of the image in the design layout is obtained by aligning the exposure pattern in the image with the corresponding design pattern in the design layout, including: extracting the initial outline of the exposure pattern in the image; By aligning the initial outline with the corresponding design drawing, the alignment position of the image in the design layout is obtained.

5. The graphic dimension measurement method as described in claim 4, characterized in that, Extracting the initial outline of the exposure pattern in the image includes: obtaining the grayscale distribution of the image, wherein the grayscale distribution includes the grayscale level corresponding to each point in the image; The positions of points in the image corresponding to gray levels higher than a preset threshold are extracted as the initial contour.

6. The graphic dimension measurement method as described in claim 5, characterized in that, Before extracting the positions of points in the image whose gray levels are higher than a preset threshold as the initial contour, the method further includes: The grayscale distribution of the image is subjected to a first smoothing process; The positions of points in the image whose gray levels are higher than a preset threshold are extracted as the initial contour. In the gray distribution after the first smoothing process, the positions of points in the image whose gray levels are higher than the preset threshold are extracted as the initial contour.

7. The graphic dimension measurement method as described in claim 6, characterized in that, The first smoothing process is applied to the grayscale distribution of the image using a first Gaussian filter.

8. The graphic dimension measurement method as described in claim 7, characterized in that, In the first smoothing process of the gray-level distribution of the image using a first Gaussian filter, the expression is used. Perform the first smoothing process, where (x,y) are the coordinates of the point corresponding to the gray level, and σ is a first preset parameter.

9. The graphic dimension measurement method as described in claim 4, characterized in that, Obtaining the alignment position of the image in the design layout by aligning the initial outline with the corresponding design drawing includes: Overlay the image with the corresponding area in the design layout; Based on the edge of the design graphic corresponding to the exposure graphic, an edge extension region is generated inside and outside the design graphic, surrounding and covering the edge of the design graphic. When the overlap rate between the initial contour and the edge extension region is maximized, the relative position of the image in the design layout is taken as the alignment position.

10. The graphic dimension measurement method as described in claim 9, characterized in that, Overlaying the image with the corresponding area in the design layout includes: setting a portion of the area in the design layout corresponding to the image as a defined area; Overlay the image onto the defined area of ​​the design layout; When the overlap rate between the initial contour and the edge extension region is maximized, the relative position of the image in the design layout is used as the alignment position, including: setting a search step size; Multiple search processes are performed within the defined region. The search process includes: moving the image to the search position based on the search step size; and obtaining the ratio of the total overlapping area of ​​the initial contour and the edge extension region to the total area of ​​the edge extension region in the image at the search position as the overlap rate. The search position corresponding to the maximum overlap rate is obtained as the alignment position.

11. The graphic dimension measurement method as described in claim 10, characterized in that, Align the corresponding coordinates between the image and the design layout to overlay the image onto the defined area of ​​the design layout.

12. The graphic dimension measurement method as described in claim 1, characterized in that, Based on the alignment position, and in conjunction with the design layout and the image, obtaining the target outline of the exposure graphic in the image includes: overlapping the image with the design layout at the alignment position; Obtain the grayscale distribution of the image, wherein the grayscale distribution includes the grayscale level corresponding to each point in the image; Based on the position of the edge mapping of the design graphic in the image, the point corresponding to the gray level equal to the preset threshold is selected as the target edge point; Connecting multiple target edge points forms the target contour.

13. The graphic dimension measurement method as described in claim 12, characterized in that, Before selecting the point corresponding to the gray level equal to the preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, the method further includes: generating an edge extension region surrounding and covering the edge of the design graphic inside and outside the design graphic, based on the edge of the design graphic corresponding to the exposure graphic. The region in the image mapped by the edge extension region is used as the detection area; Based on the position of the edge mapping of the design graphic in the image, points corresponding to gray levels equal to a preset threshold are selected as target edge points, including: selecting points corresponding to gray levels equal to a preset threshold in the detection area as initial edge points; In the extension direction perpendicular to the detection area, when there are two initial edge points in the detection area, one of the initial edge points is selected as the target edge point; In the direction perpendicular to the extension of the detection area, when there is an initial edge point in the detection area, the initial edge point is selected as the target edge point.

14. The graphic dimension measurement method as described in claim 13, characterized in that, When there are two initial edge points in the detection area, selecting one of the initial edge points as the target edge point includes: determining that the exposure pattern corresponding to the detection area is suitable for measuring the structural size or suitable for measuring the structural interval. When the exposure pattern corresponding to the detection area is suitable for measuring the structural dimensions, the initial edge point that is far from the interior of the corresponding design pattern in the extension direction perpendicular to the detection area is selected as the target edge point; When the exposure pattern corresponding to the detection area is suitable for measuring the structural interval, the initial edge point that is close to the interior of the corresponding design pattern in the extension direction perpendicular to the detection area is selected as the target edge point.

15. The graphic dimension measurement method as described in claim 12, characterized in that, Before selecting the point corresponding to the gray level equal to a preset threshold as the target edge point based on the position of the edge mapping of the design graphic in the image, the method further includes: performing a second smoothing process on the gray level distribution of the image.

16. The graphic dimension measurement method as described in claim 15, characterized in that, A second Gaussian filter is used to perform a second smoothing process on the grayscale distribution of the image.

17. The graphic dimension measurement method as described in claim 16, characterized in that, In the second smoothing process of the image's grayscale distribution using a second Gaussian filter, the expression is used. The second smoothing process is performed, where (x,y) are the coordinates of the point corresponding to the gray level, σ1 is the second preset parameter, and σ2 is the third preset parameter.

18. The graphic dimension measurement method as described in claim 12, characterized in that, By connecting multiple target edge points to form the target contour, edge fitting is performed by combining multiple target edge points to obtain the target contour.

19. The graphic dimension measurement method as described in claim 1, characterized in that, Before obtaining the size of the exposure pattern through the target contour, the method further includes: overlapping the image with the design layout at the alignment position; Calculate the edge placement error between each edge of each target contour in the image and the corresponding design graphic; The target contour is adjusted based on the edge placement error.

20. The graphic dimension measurement method as described in claim 19, characterized in that, Adjusting the target contour based on the edge placement error includes: obtaining half of the average difference of the edge placement errors of the opposite sides of each target contour extending in the horizontal direction in the image, as a first adjustment value; In the image, half of the average difference in edge placement error between opposite sides of each target contour extending in the vertical direction is taken as the second adjustment value. Each of the target contours is shifted vertically by the distance of the absolute value of the first adjustment value in the opposite direction to the first adjustment value. Each of the target contours is shifted horizontally by the absolute value of the second adjustment value in the opposite direction.

21. The graphic dimension measurement method as described in claim 1, characterized in that, Obtaining the size of the exposure pattern from the target contour includes: defining measurement marks on the image; The measurement is performed at the location of the measurement mark; or, Provide a dimension file, including coordinates corresponding to the image and measurement types corresponding to the coordinates; Based on the size file, the measurement results of the image are obtained.

22. A graphic dimension measurement system, characterized in that, include: The design layout module provides a design layout, which includes multiple design graphics. The image acquisition module is used to acquire an image of the actual exposure structure corresponding to the design layout, the image including multiple exposure patterns; The image alignment module is used to obtain the alignment position of the image in the design layout by aligning the exposure pattern in the image with the corresponding design pattern in the design layout; The target contour acquisition module is used to acquire the target contour of the exposure pattern in the image based on the alignment position, combined with the design layout and the image; A measurement module is used to obtain the size of the exposure pattern through the target contour.

23. A device, characterized in that, It includes at least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the graphic dimension measurement method as described in any one of claims 1-21.

24. A storage medium, characterized in that, The storage medium stores one or more computer instructions, which are used to implement the graphic dimension measurement method as described in any one of claims 1-21.

25. A computer program product comprising computer instructions, characterized in that, When executed by a processor, the computer instructions implement the graphic dimension measurement method according to any one of claims 1-21.

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