Method, system and equipment for measuring three-dimensional structure characteristics

Abstract

The invention provides a method, a system and equipment for measuring three-dimensional structure characteristics, which are applied to a characteristic size scanning electron microscope (CDSEM), and mainly comprise: the CDSEM comprises at least two electron guns; the at least two electron guns are arranged opposite to the to-be-detected structure, and meanwhile the distances from the electron beam emitting ends of the at least two electron guns to the to-be-detected structure are the same; enabling the at least two electron guns to emit electron beams along respective corresponding electron motion paths to scan the to-be-detected structure, and generating at least two two-dimensional scanning images; combining the at least two two-dimensional scanning images according to the electron motion paths corresponding to the at least two electron guns, and generating a total contour image of the to-be-detected structure; and extracting three-dimensional structure features of the to-be-detected structure according to the multiple pieces of feature size information. The at least two electron guns are adopted to scan the to-be-detected structure from different angles, the richness of the obtained image data can be improved, and then the accuracy of measuring the three-dimensional structure characteristics of the to-be-detected structure is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method, system and device for measuring three-dimensional structural features. Background Technology

[0002] As the critical dimension (CD) of semiconductors continues to shrink, its impact on the performance of semiconductor chips is becoming increasingly significant. Therefore, the precision requirements for feature dimensions in manufacturing processes are also increasing. Typically, a critical dimension scanning electron microscope (CDSEM) can be used to inspect the feature dimensions of semiconductors.

[0003] Specifically, in CDSEM, an electron gun emits an electron beam to scan the surface of the structure to be inspected (such as a channel structure or a bump structure) on a wafer. The electron beam interacts with the atoms on the surface of the structure to be inspected, collecting the electron signals excited by the structure (including secondary electron signals, reflected electron signals, backscattered electron signals, X-ray signals, and Auger electron signals, etc.), and generating a two-dimensional image representing the surface morphology of the structure to be inspected. Based on the two-dimensional image, the characteristic dimensions of the structure to be inspected, such as linewidth, aperture, sidewall dimensions, and other important geometric parameters, can be extracted to measure the process quality.

[0004] In related technologies, an electron gun positioned directly above the structure to be inspected first emits an electron beam. When the electron beam scans perpendicular to the structure, a two-dimensional image of the horizontal surface topography of the structure is obtained. When the electron beam scans at an angle to the structure, a two-dimensional image of the side surface topography of the structure is obtained. Next, the two types of two-dimensional images are merged according to the scanning direction to obtain a contour image of the structure. Finally, image processing is performed on the contour image to extract the CD (structure center) of the structure to be inspected.

[0005] However, due to the limitations of the shape of the structure to be detected, when the electron beam is tilted to scan the structure, only a two-dimensional image representing part of the side surface morphology of the structure can be obtained, resulting in the inability to extract all the feature dimensions of the structure. In addition, during the scanning process, the shape of the structure, the surface roughness of the structure, and the scanning environment may affect the obtained two-dimensional image and the structure itself, leading to low accuracy of the extracted CD of the structure. Summary of the Invention

[0006] The technical problem this application aims to solve is that the accuracy of the extracted CD of the structure to be detected is low.

[0007] To address the aforementioned technical problems, this application provides a method for measuring three-dimensional structural features, applied to a feature-size scanning electron microscope (CDSEM). The CDSEM includes at least two electron guns. The method includes: positioning the at least two electron guns relative to the structure to be inspected, ensuring that the distance from the electron beam emission ends of the at least two electron guns to the structure to be inspected is the same; emitting electron beams from the at least two electron guns along their respective electron motion paths to scan the structure to be inspected, generating at least two two-dimensional scan images; merging the at least two two-dimensional scan images according to the electron motion paths of the at least two electron guns to generate a total contour image of the structure to be inspected, the total contour image including multiple feature size information of the structure to be inspected; and extracting the three-dimensional structural features of the structure to be inspected based on the multiple feature size information.

[0008] In some embodiments of this application, there is an angle of inclination between the axis of the electron gun and the plane containing the structure to be detected, and the angle of inclination is between 0 degrees and 90 degrees.

[0009] In some embodiments of this application, at least two of the electron guns have the same tilt angle.

[0010] In some embodiments of this application, before the step of emitting electron beams along their respective corresponding electron motion paths to scan the structure to be detected and generating at least two two-dimensional scan images, the method further includes: in response to scanning parameters input by the user, obtaining the electron motion paths corresponding to the at least two electron guns respectively, wherein the scanning parameters include a start position, a scanning width, a scanning direction, and an end position.

[0011] In some embodiments of this application, for any one of the at least two electron guns, the step of emitting electron beams along their respective corresponding electron motion paths to scan the structure to be detected and generate at least two two-dimensional scan images includes: emitting electron beams along the corresponding electron motion paths to scan the structure to be detected, acquiring secondary electrons generated by the excited structure to be detected, generating multiple single-frame images, wherein each single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam; and merging the multiple single-frame images according to the scanning direction to generate the two-dimensional scan image.

[0012] In some embodiments of this application, after merging at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns to generate the overall contour image of the structure to be detected, the method further includes: obtaining a target region image corresponding to the structure to be detected based on the grayscale value of the overall contour image; obtaining the grayscale peak points of the target region image; and extracting the plurality of feature size information of the structure to be detected based on the peak points.

[0013] In some embodiments of this application, the number of electron guns is adapted to the structure of the structure to be detected.

[0014] In some embodiments of this application, when the structure to be detected is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be detected and perpendicular to the plane where the structure to be detected is located.

[0015] In some embodiments of this application, when the structure to be detected is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, with the four electron guns arranged opposite to the structure to be detected in pairs.

[0016] To address the aforementioned technical problems, this application also provides a three-dimensional structural feature measurement system applied to a feature-size scanning electron microscope (CDSEM). The CDSEM includes at least two electron guns and comprises: a setting module, a first generation module, a second generation module, and a first extraction module. The setting module is used to position the at least two electron guns relative to the structure to be detected, while ensuring that the distance from the electron beam emission end of the at least two electron guns to the structure to be detected is the same. The first generation module is used to enable the at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected, generating at least two two-dimensional scan images. The second generation module is used to merge the at least two two-dimensional scan images according to the electron motion paths of the at least two electron guns, generating a total contour image of the structure to be detected, the total contour image including multiple feature size information of the structure to be detected. The first extraction module is used to extract the three-dimensional structural features of the structure to be detected based on the multiple feature size information.

[0017] In some embodiments of this application, there is an angle of inclination between the axis of the electron gun and the plane containing the structure to be detected, and the angle of inclination is between 0 degrees and 90 degrees.

[0018] In some embodiments of this application, at least two of the electron guns have the same tilt angle.

[0019] In some embodiments of this application, the system further includes: a first acquisition module; the first acquisition module is used to acquire, in response to user-inputted scanning parameters, at least two electron guns corresponding to electron motion paths, before the first generation module causes at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected and generate at least two two-dimensional scan images. The scanning parameters include a start position, a scanning width, a scanning direction, and an end position.

[0020] In some embodiments of this application, for any one of at least two electron guns, the first generation module is configured to: cause the electron gun to emit an electron beam along the corresponding electron motion path to scan the structure to be detected, obtain secondary electrons generated by the excited structure to be detected, generate multiple single-frame images, wherein each single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam; and merge the multiple single-frame images according to the scanning direction to generate the two-dimensional scan image.

[0021] In some embodiments of this application, the system further includes: a second acquisition module, a third acquisition module, and a second extraction module; the second acquisition module is used to obtain a target region image corresponding to the structure to be detected based on the grayscale value of the total contour image after the second generation module merges at least two two-dimensional scan images along their respective electron motion paths according to at least two electron guns; the third acquisition module is used to obtain the grayscale peak points of the target region image; the second extraction module is used to extract the plurality of feature size information of the structure to be detected based on the peak points.

[0022] In some embodiments of this application, the number of electron guns is adapted to the structure of the structure to be detected.

[0023] In some embodiments of this application, when the structure to be detected is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be detected and perpendicular to the plane where the structure to be detected is located.

[0024] In some embodiments of this application, when the structure to be detected is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, with the four electron guns arranged opposite to the structure to be detected in pairs.

[0025] To address the aforementioned technical problems, this application also provides a measurement device for three-dimensional structural features, used to perform the measurement method for three-dimensional structural features described in any of the preceding claims.

[0026] Compared with existing technologies, the technical solution of this application employs at least two electron guns to measure the three-dimensional feature structure, scanning as many surfaces of the structure to be detected as possible, and scanning the structure from different angles. This improves the richness of the acquired image data, thereby enhancing the accuracy of measuring the three-dimensional structural features of the structure to be detected. Furthermore, the total contour signal obtained from a single measurement can capture all three-dimensional structural features, thus increasing the measurement speed of the three-dimensional structural features. Attached Figure Description

[0027] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale.

[0028] Figure 1 This is a flowchart of a first method for measuring three-dimensional structural features according to some embodiments of this application;

[0029] Figure 2 This is a schematic diagram of the first electron gun position structure shown in some embodiments of this application;

[0030] Figure 3 This is a schematic diagram of a second electron gun position structure according to some embodiments of this application;

[0031] Figure 4 This is a schematic diagram of a third electron gun position structure according to some embodiments of this application;

[0032] Figure 5 This is a flowchart illustrating a second method for measuring three-dimensional structural features according to some embodiments of this application;

[0033] Figure 6 This is a flowchart illustrating a third method for measuring three-dimensional structural features according to some embodiments of this application;

[0034] Figure 7 This is a flowchart illustrating a fourth method for measuring three-dimensional structural features according to some embodiments of this application;

[0035] Figure 8 This is a block diagram of a measurement system for three-dimensional structural features according to some embodiments of this application. Detailed Implementation

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations. It should be clearly understood that the drawings are for illustrative and descriptive purposes only and are not intended to limit the scope of this specification.

[0037] It should be understood that the terms "module" and "circuit" used herein are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they can be replaced by other expressions.

[0038] The terminology used in this application is for the purpose of describing specific example embodiments only and is not restrictive. When used in this specification, the terms "comprising," "including," and / or "containing" mean the presence of the associated integers, steps, operations, elements, and / or components, but do not preclude the presence of one or more other features, integers, steps, operations, elements, components, and / or groups, or the possibility of adding other features, integers, steps, operations, elements, components, and / or groups to the measurement method / system / device of three-dimensional structural features. When different components are described as being associated in this specification, the relationship can be direct or indirect. For example, "A and B are connected" can mean that A and B are directly connected, or that A and B are indirectly connected through other components.

[0039] CDSEM is a device used in semiconductor processes to measure the pattern CD on a semiconductor substrate. Its working principle is as follows: an electron beam emitted from an electron gun is focused by a condenser lens, passes through an opening, and reaches the pattern of the structure to be tested. The emitted secondary electrons are captured by a detector and converted into an electrical signal to obtain a two-dimensional CDSEM image and generate a corresponding CDSEM characteristic curve. Based on the CDSEM image and its corresponding CDSEM characteristic curve, the CD of the structure to be tested is measured.

[0040] In related technologies, a single gun can be used for oblique scanning to collect oblique images of all sidewalls of the top view of the structure to be detected. These images are then combined with normal images scanned from the same direction to obtain the final image. The CD of the structure to be detected is calculated based on the signal intensity of the final image, which can only provide information about the top wall or sidewalls, thus limiting its further application in three-dimensional contour detection (roughness of the lower surface or sidewalls).

[0041] Based on the above analysis, such as Figure 1As shown in the embodiment of this application, the method for measuring three-dimensional structural features includes steps S101 to S104. It is applied to a feature-size scanning electron microscope (CDSEM), which includes at least two electron guns.

[0042] Step S101: At least two of the electron guns are positioned opposite to the structure to be tested, and the distance from the electron beam emitting end of the at least two electron guns to the structure to be tested is the same.

[0043] In this application, the structure to be inspected can be a pattern on the front side of a wafer. At least two electron guns are disposed opposite to the structure to be inspected, and the at least two electron guns can be disposed on one side of the structure to be inspected, that is, at least two electron guns are disposed on the front side of the wafer.

[0044] The electron gun generates an electron beam. For example, the electron gun includes a filament, a U-shaped cap with a central hole, and an anode. The filament generates electrons; the central hole in the U-shaped cap filters electrons that stray elsewhere, initially forming a downward-moving electron beam; the anode accelerates the electrons and constrains their trajectory. This causes the generated electrons to move downwards along the beam until they hit the structure being inspected.

[0045] In some embodiments of this application, there is an angle of inclination between the axis of the electron gun and the plane containing the structure to be detected, and the angle of inclination ranges from 0 degrees to 90 degrees. For example, 15 degrees, 30 degrees, 60 degrees, 75 degrees, etc.

[0046] It is understood that the placement of the electron gun is related to the structure to be detected, and the electron beam emitted by the electron gun can scan all positions on the side of the structure to be detected. The tilt angles corresponding to at least two electron guns can be different or not exactly the same. After obtaining at least two two-dimensional scan images, the deformation degree of the two-dimensional scan image corresponding to each electron gun can be adjusted according to the tilt angle of each electron gun. Then, the adjusted at least two two-dimensional scan images are merged to generate the overall contour image of the structure to be detected. This can avoid the deviation in the degree of deformation of the two-dimensional scan images caused by different tilt angles, and improve the accuracy of the extracted three-dimensional structural features of the structure to be detected.

[0047] In some embodiments of this application, at least two electron guns have the same tilt angle. That is, at least two two-dimensional scan images obtained by at least two electron guns emitting electron beams to scan the structure under test have the same degree of deformation. The at least two two-dimensional scan images can be directly merged to generate the overall contour image of the structure under test. This can avoid the angle error of the tilt angle and the calculation error of adjusting the degree of deformation, improve the consistency between the overall contour image and the wafer, and improve the accuracy of the extracted three-dimensional structural features of the structure under test.

[0048] In some embodiments of this application, the number of electron guns is adapted to the structure of the structure to be detected.

[0049] In the first example, when the structure to be detected is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be detected and perpendicular to the plane where the structure to be detected is located.

[0050] like Figure 2 As shown, the two electron guns are arranged opposite each other on both sides of the preset plane. The electron beams emitted by the two electron guns can scan the entire sidewall (including the top, two sides and the bottom) of the structure to be detected, improve the consistency between the generated two-dimensional scan image and the structure to be detected, and thus improve the accuracy of the extracted three-dimensional structural features of the structure to be detected.

[0051] In a second example, when the structure to be detected is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, which are arranged opposite to the structure to be detected in pairs.

[0052] like Figure 3 As shown, from a top-down view of the structure under test, four electron guns are positioned corresponding to the four sidewalls, with each sidewall corresponding to a specific pair of electron guns. Two electron guns can be positioned opposite each other on either side of a first plane, which passes through the central axis of the first and second sidewalls of the structure under test and is perpendicular to the plane containing the structure. The other two electron guns can be positioned opposite each other on either side of a second plane, which passes through the central axis between the third and fourth sidewalls of the structure under test and is perpendicular to the plane containing the structure.

[0053] In this way, the electron beams emitted by the four electron guns can scan the entire sidewalls of the structure to be detected (including the top, four sides and bottom), improving the consistency between the generated two-dimensional scan image and the structure to be detected, thereby improving the accuracy of the extracted three-dimensional structural features of the structure to be detected.

[0054] In a third example, when the structure to be detected is a hemispherical structure with a spherical upper surface, the CDSEM includes three electron guns; the three electron guns are evenly arranged around the normal of the structure to be detected.

[0055] like Figure 4As shown, from a top-down view of the structure under test, three electron guns are evenly positioned around the normal of the structure, with an angle of 120 degrees between any two electron guns. This allows the electron beams emitted by the electron guns to scan the entire upper surface of the structure under test, improving the consistency between the generated two-dimensional scan image and the structure, thereby increasing the accuracy of the extracted three-dimensional structural features.

[0056] In this embodiment, at least two electron guns are used to measure the three-dimensional feature structure. Essentially, this involves scanning as much of the surface of the structure to be detected as possible. Therefore, at least two electron guns can be achieved by multiplexing individual electron guns, moving them to different positions during the multiplexing process. However, before scanning the structure to be detected, the positions of the electron guns or the structure to be detected need to be precisely aligned, requiring a long measurement preparation time. Furthermore, frequent adjustments to the electron gun positions may reduce the accuracy of the position adjustment, causing deviations between the two-dimensional scan image and the structure to be detected, thus failing to improve the accuracy of the extracted three-dimensional structural features of the structure to be detected.

[0057] Step S102: At least two electron guns emit electron beams along their respective electron motion paths to scan the structure to be detected, generating at least two two-dimensional scan images.

[0058] In the embodiments of this application, each electron gun corresponds to an electron motion path. The electron motion path refers to the scanning path of the electron beam emitted by the electron gun on the structure to be detected.

[0059] In some embodiments of this application, prior to step S102, the method for measuring three-dimensional structural features provided in this application further includes: in response to scanning parameters input by the user, acquiring at least two electron motion paths corresponding to the electron guns respectively, wherein the scanning parameters include a start position, a scanning width, a scanning direction, and an end position.

[0060] In this embodiment, the input device for the scanning parameters can be one or more external devices such as a mouse, keyboard, touchscreen, or wireless transceiver. Upon receiving the scanning parameters input by the user, at least two electronic motion paths corresponding to the electron guns are acquired in response to the scanning parameters.

[0061] In this embodiment, the starting position in the scanning parameters can be any position in the structure to be detected, typically an easily identifiable position such as the upper left, lower left, upper right, or lower right corner. The ending position in the scanning parameters corresponds to the starting position. For the area in the structure to be detected that can be scanned by an electron gun, the electron beam starts from the starting position and scans according to the scanning direction and scanning width until it ends at the ending position. The scanning direction in the scanning parameters can be from left to right, from right to left, from top to bottom, or from bottom to top.

[0062] In this embodiment, the scanning width in the scanning parameters is the width of the electron beam irradiating the structure to be inspected, such as 1 nanometer, 0.5 nanometers, etc. The number of scans is determined based on the scanning width and the area of ​​the structure to be inspected that the electron gun can scan.

[0063] For example, if the width of the top feature dimension of the structure to be detected is 10 nanometers and the scan width is 1 nanometer, then 10 scans are required. The scanning directions of the previous and subsequent electron beam scans can be the same or different. For example, the previous electron beam scan is from left to right, and after the current scan ends, the scan width is moved from the end position, and then the scan continues from right to left. Alternatively, the previous electron beam scan is from left to right, and after the current scan ends, the scan width is moved from the start position, and then the scan continues from left to right.

[0064] In some embodiments of this application, such as Figure 5 As shown, for any one of the at least two electron guns, generating a two-dimensional scan image in step S102 may include steps S1021 and S1022.

[0065] Step S1021: The electron gun emits an electron beam along the corresponding electron motion path to scan the structure to be detected, obtain the secondary electrons generated by the excited structure to be detected, and generate multiple single-frame images.

[0066] The single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam. It should be noted that if the width of the top feature dimension of the structure to be detected is 10 nanometers and the scanning width is 1 nanometer, then 10 scans are required to generate 10 single-frame images.

[0067] In one example, each single-frame image includes a valid image obtained by electron beam scanning, as well as a blank image that was not scanned.

[0068] In another example, each single-frame image includes a valid image obtained by electron beam scanning.

[0069] Step S1022: According to the scanning direction, merge multiple single-frame images to generate the two-dimensional scan image.

[0070] In some embodiments of this application, if a single-frame image includes a valid image obtained by electron beam scanning and a blank image that has not been scanned, then multiple single-frame images are merged according to the scanning direction of the previous electron beam scan and the scanning direction of the adjacent subsequent electron beam scan to generate the two-dimensional scan image.

[0071] In some embodiments of this application, if a single-frame image includes a valid image obtained by electron beam scanning, then multiple single-frame images are merged to generate the two-dimensional scan image based on the scanning direction of the previous electron beam scan, the scanning direction of the adjacent subsequent electron beam scan, and the start and end positions of the single-frame image.

[0072] In this way, at least two electron guns emit electron beams along their respective electron motion paths to scan the large detection structure, generating at least two two-dimensional scan images. The two-dimensional scan images are obtained from different angles of the same scheme (the structure to be detected), which can improve the richness of the acquired image data and thus improve the accuracy of measuring the three-dimensional structural features of the structure to be detected.

[0073] Step S103: At least two two-dimensional scan images are merged according to the respective electron motion paths of at least two electron guns to generate the overall contour image of the structure to be detected.

[0074] The overall contour image includes multiple feature size information of the structure to be detected. The feature size information may include length, width, roughness, and other information.

[0075] In some embodiments of this application, after acquiring the overall contour image, the overall contour image can be analyzed to obtain multiple feature size information. For example... Figure 6 As shown, step S103 may include steps S1031 to S1033.

[0076] Step S1031: Obtain the target region image corresponding to the structure to be detected based on the grayscale value of the overall contour image.

[0077] Step S1032: Obtain the grayscale peak points of the target region image.

[0078] Step S1033: Extract the multiple feature size information of the structure to be detected based on the grayscale peak points.

[0079] In this embodiment of the application, image processing is performed on the overall contour image, and multiple feature size information is extracted by the change of grayscale value.

[0080] Step S104: Extract the three-dimensional structural features of the structure to be detected based on the multiple feature size information.

[0081] In this embodiment, at least two electron guns detect the same pattern (the structure to be detected) from different angles. Frames collected from different directions are combined to generate a total contour image, and then the contour signals of the top, sidewalls and bottom are separated to extract the three-dimensional structural features of the structure to be detected.

[0082] In this way, the total contour signal obtained from a single measurement can capture all the three-dimensional structural features, thereby improving the measurement speed of the three-dimensional structural features.

[0083] For example, such as Figure 7 As shown in (a), the cross-section of the structure to be tested is trapezoidal, as shown in Figure (a). Figure 7 As shown in (b), two two-dimensional scan images (first image and second image) are acquired using two electron guns, as shown in Figure (b). Figure 7 As shown in (c), the two two-dimensional scan images are merged to obtain the overall contour image (the third image). Figure 7 As shown in (d), the target region image (fourth image) corresponding to the structure to be detected is obtained. The boundary point of grayscale change in the fourth image is the grayscale peak point. Figure 7 As shown in (e), the fourth image includes four feature size information: the first sidewall size, the second sidewall size, the upper surface size, and the lower surface size.

[0084] The beneficial effects that the embodiments of this application may bring include, but are not limited to: using at least two electron guns to measure the three-dimensional feature structure, scanning as many surfaces of the structure to be detected as possible, and scanning the structure to be detected from different angles can improve the richness of the acquired image data, thereby improving the accuracy of measuring the three-dimensional structural features of the structure to be detected. At the same time, all three-dimensional structural features can be obtained through the total contour signal obtained by a single measurement, which can improve the measurement speed of three-dimensional structural features.

[0085] It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects may be any one or a combination of the above, or any other possible beneficial effects.

[0086] like Figure 8 As shown, this application embodiment also provides a three-dimensional structural feature measurement system applied to a feature size scanning electron microscope (CDSEM). The CDSEM includes at least two electron guns and includes: a setting module 81, a first generation module 82, a second generation module 83, and a first extraction module 84.

[0087] The setting module 81 is used to set at least two electron guns relative to the structure to be detected, and at the same time, to make the distance from the electron beam emitting end of at least two electron guns to the structure to be detected the same.

[0088] The first generation module 82 is used to cause at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected, thereby generating at least two two-dimensional scan images;

[0089] The second generation module 83 is used to merge at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns to generate a total contour image of the structure to be detected, wherein the total contour image includes multiple feature size information of the structure to be detected;

[0090] The first extraction module 84 is used to extract the three-dimensional structural features of the structure to be detected based on the multiple feature size information.

[0091] In some embodiments of this application, there is an angle of inclination between the axis of the electron gun and the plane where the structure to be detected is located, and the angle of inclination is between 0 degrees and 90 degrees.

[0092] In some embodiments of this application, at least two of the electron guns have the same tilt angle.

[0093] In some embodiments of this application, the system further includes: a first acquisition module 85;

[0094] The first acquisition module 85 is used to acquire the electron motion paths corresponding to the at least two electron guns respectively in response to the scanning parameters input by the user before the first generation module 82 causes the at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected and generate at least two two-dimensional scan images. The scanning parameters include the start position, scanning width, scanning direction and end position.

[0095] In some embodiments of this application, for any one of at least two electron guns, the first generation module 82 is configured to: cause the electron gun to emit an electron beam along the corresponding electron motion path to scan the structure to be detected, obtain secondary electrons generated by the excited structure to be detected, generate multiple single-frame images, wherein the single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam; and merge the multiple single-frame images according to the scanning direction to generate the two-dimensional scan image.

[0096] In some embodiments of this application, the system further includes: a second acquisition module 86, a third acquisition module 87, and a second extraction module 88;

[0097] The second acquisition module 86 is used to obtain the target region image corresponding to the structure to be detected based on the grayscale value of the total contour image after the second generation module 83 merges at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns to generate the total contour image of the structure to be detected.

[0098] The third acquisition module 87 is used to acquire the grayscale peak points of the target region image;

[0099] The second extraction module 88 is used to extract the multiple feature size information of the structure to be detected based on the peak points.

[0100] In some embodiments of this application, the number of electron guns is adapted to the structure of the structure to be detected.

[0101] In some embodiments of this application, when the structure to be detected is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be detected and perpendicular to the plane where the structure to be detected is located.

[0102] In some embodiments of this application, when the structure to be detected is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, with the four electron guns arranged opposite to the structure to be detected in pairs.

[0103] In addition, this application also provides a measurement device for three-dimensional structural features for performing the aforementioned measurement method for three-dimensional structural features.

[0104] In summary, after reading this application, those skilled in the art will understand that the foregoing application content is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are all within the spirit and scope of the exemplary embodiments of this application.

[0105] It should also be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Therefore, without departing from the teachings of this application, a first element in some embodiments may be referred to as a second element in other embodiments. The same reference numerals or the same reference signs denote the same elements throughout the specification.

Claims

1. A method for measuring three-dimensional structural features, applied to a feature-dimension scanning electron microscope (CDSEM), characterized in that, The CDSEM includes at least two electron guns; including: At least two of the electron guns are positioned opposite to the structure to be tested, and the distance from the electron beam emitting end of at least two of the electron guns to the structure to be tested is the same. At least two electron guns are respectively made to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected, generating at least two two-dimensional scan images; At least two two-dimensional scan images are merged according to the respective electron motion paths of at least two electron guns to generate a total contour image of the structure to be detected, the total contour image including multiple feature size information of the structure to be detected; Based on the multiple feature size information, the three-dimensional structural features of the structure to be detected are extracted.

2. The method for measuring three-dimensional structural features as described in claim 1, characterized in that, There is an angle between the axis of the electron gun and the plane of the structure to be detected, and the angle ranges from 0 degrees to 90 degrees.

3. The method for measuring three-dimensional structural features as described in claim 2, characterized in that, At least two of the electron guns have the same tilt angle.

4. The method for measuring three-dimensional structural features as described in claim 1, characterized in that, Before generating at least two two-dimensional scan images by emitting electron beams along their respective corresponding electron motion paths from at least two electron guns to scan the structure to be detected, the method further includes: In response to the scanning parameters input by the user, at least two electron motion paths corresponding to the electron guns are obtained, wherein the scanning parameters include the start position, scanning width, scanning direction and end position.

5. The method for measuring three-dimensional structural features as described in claim 4, characterized in that, For any one of the at least two electron guns, the step of emitting electron beams from the at least two electron guns along their respective corresponding electron motion paths to scan the structure to be detected and generate at least two two-dimensional scan images includes: The electron gun emits an electron beam along the corresponding electron motion path to scan the structure to be detected, acquires the secondary electrons generated by the excited structure to be detected, and generates multiple single-frame images. Each single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam. According to the scanning direction, multiple single-frame images are merged to generate the two-dimensional scan image.

6. The method for measuring three-dimensional structural features as described in claim 1, characterized in that, After generating the overall contour image of the structure to be detected by merging at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns, the method further includes: Based on the grayscale values ​​of the overall contour image, obtain the target region image corresponding to the structure to be detected; Obtain the grayscale peak points of the target region image; Based on the peak points, extract the multiple feature size information of the structure to be detected.

7. The method for measuring three-dimensional structural features as described in claim 1, characterized in that, The number of electron guns is adapted to the structure of the structure to be detected.

8. The method for measuring three-dimensional structural features as described in claim 7, characterized in that, When the structure to be tested is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be tested and perpendicular to the plane where the structure to be tested is located.

9. The method for measuring three-dimensional structural features as described in claim 7, characterized in that, When the structure to be tested is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, which are arranged opposite to the structure to be tested in pairs.

10. A measurement system for three-dimensional structural features, applied to a feature-dimension scanning electron microscope (CDSEM), characterized in that, The CDSEM includes at least two electron guns; it includes: a setting module, a first generation module, a second generation module, and a first extraction module; The setting module is used to set at least two of the electron guns relative to the structure to be detected, and at the same time, to ensure that the distance from the electron beam emitting end of at least two of the electron guns to the structure to be detected is the same. The first generation module is used to cause at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected, thereby generating at least two two-dimensional scan images; The second generation module is used to merge at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns to generate a total contour image of the structure to be detected, wherein the total contour image includes multiple feature size information of the structure to be detected; The first extraction module is used to extract the three-dimensional structural features of the structure to be detected based on the multiple feature size information.

11. The measurement system for three-dimensional structural features as described in claim 10, characterized in that, There is an angle between the axis of the electron gun and the plane of the structure to be detected, and the angle ranges from 0 degrees to 90 degrees.

12. The measurement system for three-dimensional structural features as described in claim 11, characterized in that, At least two of the electron guns have the same tilt angle.

13. The measurement system for three-dimensional structural features as described in claim 10, characterized in that, The system further includes: a first acquisition module; The first acquisition module is used to acquire the electron motion paths corresponding to the at least two electron guns respectively in response to the scanning parameters input by the user before the first generation module causes at least two electron guns to emit electron beams along their respective corresponding electron motion paths to scan the structure to be detected and generate at least two two-dimensional scan images. The scanning parameters include the start position, scanning width, scanning direction and end position.

14. The measurement system for three-dimensional structural features as described in claim 13, characterized in that, For any one of at least two of the electron guns, the first generation module is configured to: The electron gun emits an electron beam along the corresponding electron motion path to scan the structure to be detected, acquires the secondary electrons generated by the excited structure to be detected, and generates multiple single-frame images. Each single-frame image is an image corresponding to a region of the scanning width of the surface of the structure to be detected by the electron beam. According to the scanning direction, multiple single-frame images are merged to generate the two-dimensional scan image.

15. The measurement system for three-dimensional structural features as described in claim 10, characterized in that, The system further includes: a second acquisition module, a third acquisition module, and a second extraction module; The second acquisition module is used to obtain the target region image corresponding to the structure to be detected based on the grayscale value of the total contour image after the second generation module merges at least two two-dimensional scan images according to the respective electron motion paths of at least two electron guns to generate the total contour image of the structure to be detected. The third acquisition module is used to acquire the grayscale peak points of the target region image; The second extraction module is used to extract the multiple feature size information of the structure to be detected based on the peak points.

16. The measurement system for three-dimensional structural features as described in claim 10, characterized in that, The number of electron guns is adapted to the structure of the structure to be detected.

17. The measurement system for three-dimensional structural features as described in claim 16, characterized in that, When the structure to be tested is a channel structure or a protrusion structure with a sidewall length exceeding a preset length, the CDSEM includes two electron guns; the two electron guns are arranged opposite each other on both sides of a preset plane, the preset plane passing through the axis of the structure to be tested and perpendicular to the plane where the structure to be tested is located.

18. The measurement system for three-dimensional structural features as described in claim 16, characterized in that, When the structure to be tested is a multifaceted structure with four sidewalls, the CDSEM includes four electron guns, which are arranged opposite to the structure to be tested in pairs.

19. A measurement device for three-dimensional structural features, characterized in that, A measurement method for performing any three-dimensional structural features as described in any one of claims 1-9.

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