Picture processing method and device, electronic equipment and storage medium
By performing pattern merging and signal noise reduction on the reference and scan images of the CDSEM device, the problem of difficult anchor point alignment and matching in semiconductor manufacturing is solved, thus improving measurement efficiency and success rate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2026-03-10
AI Technical Summary
When using a critical dimension scanning electron microscope (CDSEM) to measure critical dimensions, the difficulty in aligning and matching anchor points leads to a decrease in the efficiency and success rate of the measurement process. This is especially true when semiconductor process nodes reach 14nm and below, where the critical dimensions of the pattern decrease, the line spacing layer pattern becomes more uniform, and the difficulty in aligning and matching anchor points increases.
By performing pattern merging processing on the reference image of the target wafer, a first matching image containing blocky patterns is obtained. Then, by performing signal noise reduction processing on the scanned image in the scanning window, a second matching image containing blocky patterns is obtained. Image processing techniques are used to improve the success rate of pattern alignment.
This greatly improves the success rate of anchor point matching, increases the efficiency of the measurement process, and makes the graphic alignment process smoother and more efficient.
Smart Images
Figure CN121639746A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductors, and in particular to a picture processing method and device, electronic equipment and a storage medium. BACKGROUND
[0002] In each link of semiconductor design, manufacturing and packaging, repeated detection and testing are performed to ensure product quality, so as to develop devices meeting system requirements. Therefore, detection equipment plays an irreplaceable important role from design verification to the entire semiconductor manufacturing process. As a key to optimizing process control yield, improving efficiency and reducing cost, the future position of detection equipment in the semiconductor industry will become increasingly prominent.
[0003] Broadly speaking, detection equipment is divided into front-end metrology and back-end testing equipment. The object of metrology is a wafer in the process, and the object of testing is a chip after the process is completed. Front-end metrology measures or checks the quality of each process to ensure that the process meets the preset indicators and prevents unqualified wafers with deviations and defects from entering the next process flow. Front-end metrology is divided into metrology and detection according to the testing purpose. According to the application, it is mainly divided into critical dimension measurement, film thickness measurement, overlay alignment measurement, mask / photomask detection, non-pattern wafer detection, patterned wafer detection and defect review.
[0004] Among them, the critical dimension scanning electron microscope (Critical Dimension Scanning Electronic Microscope, CDSEM) can be used for critical dimension measurement. The working principle of the critical dimension scanning electron microscope CDSEM is that the electron beam emitted from the electron gun is converged through the condenser lens, passes through the aperture to the pattern of the measured object, the secondary electrons emitted are captured by the detector and converted into an electrical signal, and a two-dimensional image is obtained. Based on the two-dimensional image information, the critical dimension of the measured object is measured with high precision.
[0005] However, in the process of using the critical dimension scanning electron microscope CDSEM to measure the critical dimension, there are still some problems that greatly reduce the efficiency and success rate of the measurement process. SUMMARY
[0006] To solve the above technical problems, the present application provides a picture processing method, device, electronic equipment and storage medium.
[0007] In one aspect, the present application discloses a picture processing method, comprising:
[0008] The reference image of the target numeric sample is subjected to pattern merging processing to obtain a first matching image containing blocky graphics; the blocky graphics in the first matching image contain a preset blocky graphic obtained by preset graphic processing;
[0009] The scanned image of the target wafer in the scanning window is subjected to signal denoising processing to obtain a second matching image containing blocky graphics; the reference image and the scanned image contain line elements and spacing elements;
[0010] If, during the alignment process, the blocky graphic in the second matching graphic contains the preset blocky graphic in the first matching image, the alignment is confirmed to be successful.
[0011] In some possible embodiments, before performing pattern merging processing on a reference image of the target wafer to obtain a first matching image containing blocky patterns, the method further includes:
[0012] Determine the reference image of the target wafer and the corresponding location information of the reference image. The reference image contains a preset graphic.
[0013] In some possible embodiments, determining a reference image of the target wafer includes:
[0014] Obtain an initial image of the target wafer; the initial image contains measurement points;
[0015] The candidate region in the initial image is determined based on the measurement points and preset distances in the initial image;
[0016] Reference images are determined from the candidate areas based on preset graphic density and preset graphic difference; the graphic difference of the preset graphics contained in the reference images meets the preset graphic difference.
[0017] In some possible embodiments, before performing signal denoising processing on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky patterns, the method further includes:
[0018] The scanning window is determined based on the location information corresponding to the reference image and the origin information of the target wafer, using the scanned image obtained from the preset wafer.
[0019] In some possible embodiments, the reference image includes measurement points.
[0020] In some possible embodiments, a reference image of the target wafer is subjected to pattern merging processing to obtain a first matching image containing blocky patterns, including:
[0021] The reference image is pattern merged along the line spacing direction in the reference image, so that the first region in the reference image is converted to the first grayscale color and the second region in the reference image is converted to the second grayscale color, resulting in a first matching image containing blocky graphics; the color of the blocky graphics in the first matching image is the second grayscale color;
[0022] The first region consists of line elements and spacing elements of a preset size for the edges of the line elements; the second region consists of spacing elements of a non-preset size.
[0023] In some possible embodiments, the image processing method is applied to a critical-size scanning electron microscope (CDSEM) device.
[0024] On the other hand, embodiments of this application disclose an image processing apparatus, including:
[0025] The first image processing module is configured to perform pattern merging processing on a reference image of the target nub to obtain a first matching image containing blocky graphics; the blocky graphics in the first matching image include a preset blocky graphic obtained by preset graphic processing;
[0026] The second image processing module is configured to perform signal noise reduction processing on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky graphics; the reference image and the scanned image contain line elements and spacing elements;
[0027] The graphic alignment module is configured to determine that the graphic alignment is successful if, during the graphic alignment process, the block graphic in the second matching graphic contains a preset block graphic in the first matching image.
[0028] In some possible embodiments, the apparatus further includes an image information determination module configured to perform:
[0029] Determine the reference image of the target wafer and the corresponding location information of the reference image. The reference image contains a preset graphic.
[0030] In some possible embodiments, the image information determination module is configured to perform:
[0031] Obtain an initial image of the target wafer; the initial image contains measurement points;
[0032] The candidate region in the initial image is determined based on the measurement points and preset distances in the initial image;
[0033] Reference images are determined from the candidate areas based on preset graphic density and preset graphic difference; the graphic difference of the preset graphics contained in the reference images meets the preset graphic difference.
[0034] In some possible embodiments, the apparatus further includes a scanned image determination module configured to perform:
[0035] The scanning window is determined based on the location information corresponding to the reference image and the origin information of the target wafer, using the scanned image obtained from the preset wafer.
[0036] In some possible embodiments, the reference image includes measurement points.
[0037] In some possible embodiments, the first image processing module is configured to perform:
[0038] The reference image is pattern merged along the line spacing direction in the reference image, so that the first region in the reference image is converted to the first grayscale color and the second region in the reference image is converted to the second grayscale color, resulting in a first matching image containing blocky graphics; the color of the blocky graphics in the first matching image is the second grayscale color;
[0039] The first region consists of line elements and spacing elements of a preset size for the edges of the line elements; the second region consists of spacing elements of a non-preset size.
[0040] In some possible embodiments, the image processing apparatus is applied to a critical-size scanning electron microscope (CDSEM) device.
[0041] On the other hand, embodiments of this application disclose an electronic device, including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute instructions to implement the above-described image processing method.
[0042] On the other hand, embodiments of this application disclose a computer-readable storage medium that, when the instructions in the computer-readable storage medium are executed by the processor of an electronic device, enables the electronic device to perform the above-described image processing method.
[0043] On the other hand, embodiments of this application disclose a computer program product, which includes a computer program stored in a readable storage medium. At least one processor of a computer device reads from the readable storage medium and executes the computer program, causing the device to perform the above-described image processing method.
[0044] The technical solution provided in this application has the following technical effects:
[0045] The image processing method includes performing pattern merging processing on a reference image of the target wafer to obtain a first matching image containing blocky graphics. The blocky graphics in the first matching image include a preset blocky graphic obtained by preset graphic processing. Signal denoising processing is performed on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky graphics. The reference image and the scanned image contain line elements and spacing elements. If, during the graphic alignment process, the blocky graphics in the second matching image include the preset blocky graphic in the first matching image, the graphic alignment is determined to be successful. In this embodiment, both the reference image and the scanned image are preprocessed through image processing, making them images with simple structures but obvious features, containing blocky structures, which greatly improves the success rate of anchor point matching and increases the efficiency of the measurement process. Attached Figure Description
[0046] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0047] Figure 1 This is a schematic flowchart of an image processing method provided in an embodiment of this application;
[0048] Figure 2 This is a flowchart illustrating a method for determining a reference image of a target wafer according to an embodiment of this application;
[0049] Figure 3 This is a schematic diagram of a reference image provided in an embodiment of this application;
[0050] Figure 4 This is a schematic diagram of a first matching image provided in an embodiment of this application;
[0051] Figure 5 This is a schematic diagram of a scanned image provided in an embodiment of this application;
[0052] Figure 6 This is a schematic diagram of a second matching image provided in an embodiment of this application;
[0053] Figure 7 This is a schematic diagram illustrating signal changes during image processing, provided in an embodiment of this application.
[0054] Figure 8 This is a block diagram of an image processing device provided in an embodiment of this application. Detailed Implementation
[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0056] It should be noted that the term "an embodiment" or "embodiment" in the specification of the embodiments of this application refers to a specific feature, structure, or characteristic that can be included in at least one implementation of this application. It should be understood that in the specification, claims, and accompanying drawings of the embodiments of this application, the terms "upper," "lower," "top," "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, in the description of this embodiment, unless otherwise stated, "a plurality of" means two or more. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, or product that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.
[0057] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.
[0058] To make the objectives, technical solutions, and advantages disclosed in the embodiments of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of this application and are not intended to limit the embodiments of this application.
[0059] The critical dimension scanning electron microscope (CDSEM) has been widely used in the measurement of critical dimensions in semiconductor manufacturing. Before scanning for process weaknesses, CDSEM is used to measure and evaluate process dimension specifications, process window size, etc., so that the pattern manufacturing meets process requirements and satisfies process window requirements. It has become an industry evaluation standard.
[0060] As semiconductor process nodes enter 14nm and below, the critical dimensions of patterns gradually decrease, and the spacing between patterns gradually becomes closer. The patterns on our single photomask become more and more simple, basically a combination of single lines and spaces, especially in line-space layers (such as mental layers). This makes it difficult to align and match anchor points when using CDSEM for measurement, causing great trouble for the measurement work.
[0061] In one possible embodiment, CDSEM measurement may include the following steps: First, placing the wafer (or bare die) into a wafer cassette placed on the CDSEM and performing basic wafer alignment; Second, after wafer alignment, anchor point alignment and matching on the wafer may be performed; Third, after successful anchor point alignment, calculating the position of the measurement point and measuring the critical dimensions of the measurement point.
[0062] In view of this, embodiments of this application may provide an image processing method to reduce the difficulty of anchor point alignment and matching, laying the groundwork for subsequent measurement of the critical dimensions of measurement points. Figure 1 This is a flowchart illustrating an image processing method according to an exemplary embodiment. It should be noted that this specification provides the method operation steps as shown in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only execution order. In actual systems or products, the methods can be executed sequentially or in parallel (e.g., in a parallel processor or multi-threaded processing environment) as shown in the embodiments or drawings. Specifically, as... Figure 1 As shown, this flowchart includes at least the following steps S101-S105:
[0063] In step S101, the reference image of the target wafer is subjected to pattern merging processing to obtain a first matching image containing blocky patterns; the blocky patterns in the first matching image include preset blocky patterns obtained by preset pattern processing.
[0064] In an optional embodiment, the subject of steps S101-105 and the related implementation methods can be a measurement system, which includes a key-size scanning electron microscope (CDSEM) device and an image processing device. Optionally, the image processing device can perform pattern merging processing on a reference image of the target substrate to obtain a first matching image containing blocky patterns, wherein the blocky patterns in the first matching image include preset blocky patterns obtained by preset pattern processing.
[0065] In another optional embodiment, the subject of steps S101-105 and the related implementation methods can be a key-size scanning electron microscope (CDSEM) device, which may integrate image processing software. The key-size scanning electron microscope (CDSEM) device uses the image processing software to perform pattern merging processing on a reference image of the target slide to obtain a first matching image containing blocky patterns. The blocky patterns in the first matching image include preset blocky patterns obtained through preset pattern processing.
[0066] The two execution subjects mentioned above, namely the measurement system or the key dimension scanning electron microscope (CDSEM) device, are two optional embodiments of this application. They do not limit the execution subject of this application, and any execution subject applicable to the embodiments of this application can be accepted.
[0067] In this embodiment of the application, before performing pattern merging processing on the reference image of the target wafer to obtain a first matching image containing block-shaped graphics, the process of obtaining the reference image is also included.
[0068] In one optional embodiment, registration can be performed by manually selecting registrable points on the target wafer. This involves manually selecting a suitable pattern on the target wafer and taking a photograph to obtain a reference image containing the appropriate pattern. Optionally, during the selection of a suitable pattern, it can be chosen from patterns with high pattern density, and the suitable pattern needs to be significantly different from other patterns. In other words, the selected suitable pattern should ideally be surrounded by as many other patterns as possible to ensure that the pattern density within the subsequent scanning window meets certain requirements. Furthermore, the selected suitable pattern should be highly different from its surrounding patterns, the more unique the better, to greatly reduce the difficulty of the subsequent matching process. The resulting suitable pattern is the preset pattern.
[0069] In another alternative embodiment, a reference image of the target substrate can be acquired by an image processing device in the measurement system. After performing pattern merging processing on the reference image of the target substrate to obtain a first matching image containing blocky patterns, the image is sent to a key-size scanning electron microscope (CDSEM) device so that the key-size scanning electron microscope (CDSEM) device can use the first matching image to perform subsequent pattern alignment processes.
[0070] In another alternative embodiment, the CDSEM (Critical Dimension Scanning Electron Microscope) device can acquire a reference image of the target slide using image processing software, and perform pattern merging processing on the reference image of the target slide to obtain a first matching image containing blocky patterns. The first matching image is saved so that the CDSEM device can use the first matching image to perform subsequent pattern alignment processes.
[0071] The following describes, through an optional implementation, how an image processing device in a measurement system, or a CDSEM device containing image processing software, determines a reference image for a target wafer. Figure 2 This is a flowchart illustrating a method for determining a reference image of a target wafer according to an exemplary embodiment, such as... Figure 2 As shown, steps S201-S205 are included:
[0072] In step S201, an initial image of the target wafer is obtained; the initial image contains measurement points.
[0073] In one alternative embodiment, the pattern on the entire surface of the target wafer can be photographed to obtain an initial image. Since the measurement points are one or more measurement points on the target wafer, the initial image obtained contains the measurement points.
[0074] In another alternative embodiment, the pattern near the measurement point can be photographed to obtain an initial image containing the measurement point, wherein the pattern contained in the initial image only includes a portion of the pattern on the entire surface of the target wafer.
[0075] Optionally, if there are multiple measurement points that are relatively concentrated, the number of initial images can be one. Optionally, if there are multiple measurement points that are relatively dispersed, the number of initial images can be multiple depending on the degree of clustering of the measurement points. For example, if there are N measurement points that are relatively dispersed, then N initial images can be obtained. For example, if there are N measurement points that are concentrated in two groups, then N-1 initial images can be obtained. Optionally, the same subsequent steps can be performed on each initial image.
[0076] Optionally, if there are multiple measurement points that are relatively scattered, a single image containing all the measurement points can be taken as the initial image.
[0077] In step S203, the candidate area in the initial image is determined based on the measurement points and preset distances in the initial image.
[0078] As can be seen from the above, after the anchor point alignment and matching, that is, after the subsequent graphic alignment process is successfully executed, it is necessary to calculate the measurement points and measure the key dimensions of the measurement points. Therefore, an area close to the measurement points can be determined, and then a suitable graphic can be selected from that area, namely the preset graphic in step S101.
[0079] In this embodiment, the candidate region in the initial image can be determined based on the measurement points and preset distances in the initial image. Optionally, a circular candidate region can be obtained with the measurement points as the origin and the preset distance as the radius. Optionally, a polygonal candidate region can be obtained with the measurement points as the center point and the preset distance as the shortest distance from the center point to the edge.
[0080] In step S205, a reference image is determined from the candidate area based on a preset graphic density and a preset graphic difference degree; the graphic difference degree of the preset graphics contained in the reference image meets the preset graphic difference degree.
[0081] In this embodiment of the application, a reference image can be determined from the candidate area according to a preset graphic density and a preset graphic difference degree, wherein the graphic difference degree of the preset graphic contained in the reference image satisfies the preset graphic difference degree.
[0082] Specifically, a suitable graphic, i.e. a preset graphic, can be determined from the candidate area based on the preset graphic density and preset graphic difference. Then, a reference image containing the preset graphic can be cropped based on the candidate area.
[0083] Figure 3 This is a schematic diagram of a reference image according to an exemplary embodiment, such as... Figure 3 As shown, this includes reference image 300, and the preset graphic 301 enclosed by the dashed rectangle on reference image 300. (As shown...) Figure 3 As shown, reference image 300 includes line elements and spacing elements. That is, the reference image reflects a combination of a single line and a space. In semiconductor structures, the combination of line and space can generally be referred to as a line-space layer.
[0084] In another optional embodiment, measurement points on the target wafer can be determined first, an initial image of the target wafer can be determined based on the measurement points in the initial image and a preset distance, and a reference image can be determined from the initial image of the target wafer according to a preset pattern density and a preset pattern difference degree, wherein the pattern difference degree of the preset pattern contained in the reference image satisfies the preset pattern difference degree.
[0085] Optionally, an initial circular image can be obtained by using the measurement point as the origin and a preset distance as the radius. Optionally, an initial polygonal image can be obtained by using the measurement point as the center point and a preset distance as the shortest distance from the center point to the edge.
[0086] Thus, this application can obtain reference images according to different implementation methods, and the preset graphics contained in the reference images should preferably be very different from the surrounding graphics, and there should be as many graphics as possible around the preset graphics, so as to ensure that the graphic density in the subsequent scanning window meets certain requirements.
[0087] In this embodiment of the application, after determining the reference image containing the special preset graphic, it is possible to... Figure 3 The reference image shown is processed to make the processed image easier and faster in the subsequent graphic alignment process.
[0088] In one optional embodiment, the reference image can be pattern merged along the line spacing direction in the reference image, so that the first region in the reference image is converted into a first grayscale color, and the second region in the reference image is converted into a second grayscale color, resulting in a first matching image containing blocky graphics; the color of the blocky graphics in the first matching image is the second grayscale color. The first region consists of line elements and spacing elements of a preset size for the edges of the line elements, while the second region consists of spacing elements of a non-preset size.
[0089] Figure 4 This is a schematic diagram illustrating a first matching image according to an exemplary embodiment, such as... Figure 4 As shown, including by Figure 3 The reference image 300 shown is processed by pattern merging to obtain the first matching image 400.
[0090] like Figure 3 As shown, the reference image consists of vertical lines and spacing intervals. Based on this, the horizontal direction can be regarded as the direction of line spacing in the embodiments of this application.
[0091] In this embodiment of the application, if the line-space layer does not contain [a specific element]... Figure 3 The blank areas of the preset graphic shown have the same spacing between adjacent lines, all of which are of the same preset size. Figure 3 The blank areas in the preset graphics shown generally represent areas without any components, such as metal lines.
[0092] Therefore, the reference image can be pattern merged along the line spacing direction in the reference image, so that the first region in the reference image, containing the lines and the spacing of a preset size next to the lines, is converted into a first grayscale color. Figure 4 The black color shown includes spacing that is not a preset size. Figure 3 The second area of the blank area shown is converted to the second grayscale color. Figure 4 (shown as white), to obtain the first matching image containing a blocky graphic, which is obtained by converting the blank area to grayscale.
[0093] In step S103, the scanned image of the target wafer in the scanning window is subjected to signal denoising processing to obtain a second matching image containing blocky graphics; the reference image and the scanned image contain line elements and spacing elements.
[0094] In this embodiment, signal denoising processing can be performed on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky patterns. Optionally, pattern merging processing can be performed on the reference image of the target wafer first to obtain a first matching image containing blocky patterns, and then signal denoising processing can be performed on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky patterns. Alternatively, signal denoising processing can be performed on the scanned image of the target wafer in the scanning window first to obtain a second matching image containing blocky patterns, and then pattern merging processing can be performed on the reference image of the target wafer to obtain a first matching image containing blocky patterns.
[0095] In this embodiment of the application, before performing signal denoising processing on the scanned image of the target die in the scanning window to obtain a second matching image containing blocky patterns, the position information corresponding to the reference image can be determined first, so that the scanning window can be moved to a suitable position of the target die in the wafer cassette placed on the CDSEM device according to the position information corresponding to the reference image.
[0096] In this embodiment, the positional information corresponding to the reference image can be the coordinate information of the corresponding graphic on the target wafer relative to the origin of the target wafer. Specifically, it can be a point in the corresponding graphic on the target wafer (e.g., Figure 3 The coordinates of the top right corner of the first rectangle from top to bottom relative to the origin of the target wafer.
[0097] When the coordinates of a point in the corresponding pattern on the target die relative to the origin of the target die are obtained, and the origin of the target die within the wafer cell on the CDSEM device coincides with the center point of the scanning window (i.e., basic die alignment is achieved), the target die on the CDSEM device can be moved according to the position information corresponding to the reference image and the origin information of the target die. This is to move the corresponding pattern of the preset pattern in the reference image onto the target die into the scanning window. For example, ... Figure 3 The top right corner of the first rectangle from top to bottom is moved to coincide with the center point of the scanning window, and the scanned image is obtained based on the graphic on the target wafer within the scanning window.
[0098] In one optional embodiment, when the preset pattern in the reference image corresponds to the pattern on the target wafer, the scanning window is moved in, for example, by... Figure 3 Once the point at the upper right corner of the first rectangle from top to bottom is moved to coincide with the center point of the scanning window, the key dimension scanning electron microscope (CDSEM) can focus the electron beam emitted from the electron gun through the condenser lens, pass through the aperture, and reach the pattern of the object being measured. The detector captures the emitted secondary electrons and converts them into electrical signals to obtain a two-dimensional image, i.e., a scanned image.
[0099] Figure 5 This is a schematic diagram illustrating a scanned image according to an exemplary embodiment, such as... Figure 5 As shown, this includes scanned image 500 corresponding to the scanned window. Similarly, as... Figure 5 As shown, the scanned image 500 includes line elements and spacing elements, meaning the reference image reflects a combination of a single line and a space.
[0100] In this embodiment of the application, after obtaining the scanned image, signal noise reduction processing can be performed on the scanned image to obtain a second matching image containing blocky graphics.Figure 6 This is a schematic diagram illustrating a second matching image according to an exemplary embodiment, such as... Figure 6 As shown, it contains the second matching image 600.
[0101] In this embodiment of the application, the scanned image can be subjected to signal noise reduction processing to obtain a second matching image. Figure 7 This is a schematic diagram illustrating signal changes during image processing according to an exemplary embodiment, combined with... Figure 7 The process begins by denoising the CDSEM scan signal (scanned image) at its anchor point. Using typical image processing programs, algorithms based on grayscale and frequency differences are employed to reduce background noise and enhance key graphics, filtering out unwanted elements. Figure 7 The first image in the diagram features a repetitive background structure, preserving key strong signals, such as... Figure 7 The second image shown. Thus, the scanned image becomes as follows. Figure 6 The second matching image shown is a large, easily distinguishable image containing blocky graphics.
[0102] Thus, embodiments of this application can obtain a second matching image based on CDSEM scan signals and signal processing.
[0103] In step S105, if during the graphic alignment process, the block graphic in the second matching graphic contains the preset block graphic in the first matching image, the graphic alignment is determined to be successful.
[0104] Next, the first and second matching images can be aligned graphically. Since the scanned images mentioned above are determined based on the positional information corresponding to the reference images, there are patterns in the scanned images that match the preset patterns in the reference images. However, because the patterns on the bare wafer are very small, there may still be some deviation in positioning based on the positional information. Therefore, the first and second matching images can be aligned graphically to achieve alignment through the alignment anchor points of the special preset patterns.
[0105] Optionally, if during pattern alignment, the block pattern in the second matching pattern includes the preset block pattern in the first matching image, the pattern alignment is determined to be successful. If during pattern alignment, the block pattern in the second matching pattern does not include the preset block pattern in the first matching image, the pattern alignment is determined to be unsuccessful. In such cases, it is possible to check whether the positional information corresponding to the reference image is incorrect, whether the wafer alignment is incorrect, etc.
[0106] Once the graphic is successfully aligned, i.e. the anchor point is successfully aligned and matched, the position of the measurement point can be measured and the key dimensions of the measurement point can be measured. In an optional embodiment, the reference image may contain the measurement point or the measurement point may be within a certain distance from the graphic in the reference image.
[0107] In summary, the implementation method of this application is applicable to all line-space layers under advanced nodes. Furthermore, both the reference image and the scanned image have undergone image processing preprocessing, transforming them into images with simple structures but distinct features, containing block-like structures. This significantly improves the success rate of anchor point matching and enhances the efficiency of the measurement process.
[0108] Figure 8 This is a block diagram of an image processing apparatus according to an exemplary embodiment. The apparatus is applied to an image processing method and has the function of implementing the data processing method in the above-described method embodiment. The function can be implemented in hardware or by hardware executing corresponding software. (Refer to...) Figure 8 The device includes a first image processing module 801, a second image processing module 802, and an image alignment module 803.
[0109] The first image processing module 801 is configured to perform pattern merging processing on a reference image of the target nub to obtain a first matching image containing blocky graphics; the blocky graphics in the first matching image include a preset blocky graphic obtained by preset graphic processing;
[0110] The second image processing module 802 is configured to perform signal noise reduction processing on the scanned image of the target wafer in the scanning window to obtain a second matching image containing blocky graphics; the reference image and the scanned image contain line elements and spacing elements;
[0111] The graphic alignment module 803 is configured to determine that the graphic alignment is successful if, during the graphic alignment process, the block graphic in the second matching graphic contains a preset block graphic in the first matching image.
[0112] In some possible embodiments, the apparatus further includes an image information determination module configured to perform:
[0113] Determine the reference image of the target wafer and the corresponding location information of the reference image. The reference image contains a preset graphic.
[0114] In some possible embodiments, the image information determination module is configured to perform:
[0115] Obtain an initial image of the target wafer; the initial image contains measurement points;
[0116] The candidate region in the initial image is determined based on the measurement points and preset distances in the initial image;
[0117] Reference images are determined from the candidate areas based on preset graphic density and preset graphic difference; the graphic difference of the preset graphics contained in the reference images meets the preset graphic difference.
[0118] In some possible embodiments, the apparatus further includes a scanned image determination module configured to perform:
[0119] The scanning window is determined based on the location information corresponding to the reference image and the origin information of the target wafer, using the scanned image obtained from the preset wafer.
[0120] In some possible embodiments, the reference image includes measurement points.
[0121] In some possible embodiments, the first image processing module is configured to perform:
[0122] The reference image is pattern merged along the line spacing direction in the reference image, so that the first region in the reference image is converted to the first grayscale color and the second region in the reference image is converted to the second grayscale color, resulting in a first matching image containing blocky graphics; the color of the blocky graphics in the first matching image is the second grayscale color;
[0123] The first region consists of line elements and spacing elements of a preset size for the edges of the line elements; the second region consists of spacing elements of a non-preset size.
[0124] In some possible embodiments, the image processing apparatus is applied to a critical-size scanning electron microscope (CDSEM) device.
[0125] It should be noted that the apparatus provided in the above embodiments is only illustrated by the division of the above functional modules when implementing its functions. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.
[0126] On the other hand, embodiments of this application disclose an electronic device, including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to execute instructions to implement the above-described image processing method.
[0127] On the other hand, embodiments of this application disclose a computer-readable storage medium that, when the instructions in the computer-readable storage medium are executed by the processor of an electronic device, enables the electronic device to perform the above-described image processing method.
[0128] On the other hand, embodiments of this application disclose a computer program product, which includes a computer program stored in a readable storage medium. At least one processor of a computer device reads from the readable storage medium and executes the computer program, causing the device to perform the above-described image processing method.
[0129] The electronic devices described in this application can be any electronic product or device such as smartphones, desktop computers, tablets, laptops, digital assistants, augmented reality (AR) / virtual reality (VR) devices, smart voice interaction devices, smart home appliances, smart wearable devices, and in-vehicle terminal devices, or any intermediate product including the aforementioned storage devices.
[0130] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0131] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.
[0132] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.
[0133] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A picture processing method, characterized by, The method comprises the following steps: performing pattern merging processing on a reference picture of a target wafer to obtain a first matching picture containing block patterns; the block patterns in the first matching picture contain preset block patterns obtained by preset pattern processing; performing signal noise reduction processing on a scan picture of the target wafer in a scan window to obtain a second matching picture containing block patterns; the reference picture and the scan picture contain line elements and pitch elements; if the block patterns in the second matching picture contain the preset block patterns in the first matching picture during pattern alignment, it is determined that the pattern alignment is successful.
2. The picture processing method of claim 1, wherein, Before the step of performing pattern merging processing on the reference picture of the target wafer to obtain the first matching picture containing block patterns, the method further comprises the following steps: determining the reference picture of the target wafer and position information corresponding to the reference picture; the reference picture contains the preset pattern.
3. The picture processing method of claim 2, wherein, The step of determining the reference picture of the target wafer comprises the following steps: obtaining an initial picture of the target wafer; the initial picture contains measurement points; determining a candidate region in the initial picture based on the measurement points in the initial picture and a preset distance; determining the reference picture from the candidate region according to a preset pattern density and a preset pattern difference; the pattern difference of the preset pattern contained in the reference picture meets the preset pattern difference.
4. The picture processing method of claim 2, wherein, Before the step of performing signal noise reduction processing on the scan picture of the target wafer in the scan window to obtain the second matching picture containing block patterns, the method further comprises the following steps: determining a scan picture of the target wafer based on the preset wafer obtained by the scan window according to the position information corresponding to the reference picture and origin information of the target wafer.
5. The picture processing method of any of claims 1-4, wherein, The reference picture contains the measurement points.
6. The picture processing method of claim 1, wherein, The step of performing pattern merging processing on the reference picture of the target wafer to obtain the first matching picture containing block patterns comprises the following steps: performing pattern merging processing on the reference picture along the line pitch direction in the reference picture to convert a first region in the reference picture into a first gray color and a second region in the reference picture into a second gray color, so as to obtain the first matching picture containing block patterns; the color of the block patterns in the first matching picture is the second gray color; wherein the first region is composed of line elements and pitch elements with a preset size of the edges of the line elements; and the second region is composed of pitch elements with a non-pre-set size.
7. The picture processing method of claim 1, wherein, The picture processing method is applied to a critical dimension scanning electron microscope (CDSEM) device.
8. An image processing apparatus, characterized by comprising: The method comprises the following steps: a first picture processing module configured to perform pattern merging processing on a reference picture of a target wafer to obtain a first matching picture containing block patterns; the block patterns in the first matching picture contain preset block patterns obtained by preset pattern processing; a second picture processing module configured to perform signal noise reduction processing on a scan picture of the target wafer in a scan window to obtain a second matching picture containing block patterns; the reference picture and the scan picture contain line elements and pitch elements; The pattern alignment module is configured to determine that the pattern alignment is successful if, in the pattern alignment process, a block pattern in the second matching picture contains the preset block pattern in the first matching picture.
9. An electronic device, comprising: The method comprises: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to execute the instructions to implement the picture processing method of any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, When the instructions in the computer readable storage medium are executed by the processor of the electronic device, the electronic device is enabled to perform the picture processing method of any one of claims 1 to 7.
11. A computer program product, characterised in that, The computer program product comprises a computer program stored in a readable storage medium, and at least one processor of a computer device reads and executes the computer program from the readable storage medium, so that the device performs the picture processing method of any one of claims 1 to 7.