Charged particle beam device and analysis method

Abstract

Provided is a charged particle beam device capable of shortening the acquisition time of a feature image. In this charged particle beam device, an image acquisition unit acquires a plurality of feature images by repeating: a process for selecting one mode from a plurality of modes for acquiring the feature images on the basis of the proportion of a region of a feature object in an acquired sample image in the field of view; and a process for acquiring a feature image in the selected mode, the plurality of modes including: a first mode in which a sample image is captured by scanning the sample at a first scanning speed, and the captured sample image is cut to acquire the feature image; and a second mode in which a sample image is captured by scanning the sample at a second scanning speed faster than the first scanning speed, and a feature image is captured by scanning a region of the feature object in the captured sample image at a third scanning speed slower than the second scanning speed.

Description

TECHNICAL FIELD

[0001] The present application relates to a charged particle beam device and an analysis method. BACKGROUND

[0002] Particle analysis using a scanning electron microscope (SEM), an electron probe microanalyzer (EPMA), or the like is known.

[0003] For example, Patent Literature 1 discloses a particle analysis method which extracts particles using a contrast threshold value set in advance with a standard sample or the like while acquiring a reflected electron image or a secondary electron image, and measures characteristic X-rays with an energy dispersive X-ray spectrometer, thereby classifying the particles using intensity values or concentration values thereof, and repeatedly performing the measurement until the measurement of the entire field of view set in advance is completed.

[0004] Prior art documents

[0005] Patent documents

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2015-148499 SUMMARY

[0007] Problems to be solved by the invention

[0008] In particle analysis, a particle image is repeatedly acquired, and a majority of the particles are analyzed. Therefore, in particle analysis, a long time is required for measurement in order to acquire a particle image.

[0009] Solution to the problem

[0010] One aspect of the charged particle beam device of the present application includes:

[0011] a measurement unit that photographs a sample image by scanning a sample with a charged particle beam;

[0012] an image acquisition unit that acquires a plurality of sample images photographed in a plurality of regions of the sample, acquires a characteristic image from each of the plurality of sample images, the characteristic image being an image of a characteristic object included in the sample; and

[0013] an analysis unit that acquires information of the characteristic object based on the characteristic image,

[0014] The image acquisition unit acquires a plurality of the characteristic images by repeatedly performing the following process:

[0015] selecting one mode for taking the feature image from a plurality of modes based on a proportion of an area of the feature in a field of view in a specimen image that has been taken, and

[0016] taking the feature image in the selected mode,

[0017] The plurality of modes include:

[0018] a first mode in which a specimen is scanned at a first scanning speed to take a specimen image, and the taken specimen image is cropped to take the feature image, and

[0019] a second mode in which the specimen is scanned at a second scanning speed faster than the first scanning speed to take a specimen image, and an area of the feature in the taken specimen image is scanned at a third scanning speed slower than the second scanning speed to take the feature image.

[0020] In such a charged particle beam device, it is possible to shorten the time for taking a feature image.

[0021] One aspect of the analysis method of the present application is an analysis method in a charged particle beam device that takes a specimen image by scanning a specimen with a charged particle beam, including:

[0022] a step of taking a plurality of specimen images taken in a plurality of areas of the specimen, and a step of taking a feature image from each of the plurality of specimen images, the feature image being an image of a feature included in the specimen, and

[0023] a step of taking information of the feature based on the feature image,

[0024] The step of taking the feature image takes a plurality of the feature images by repeating the following steps:

[0025] a step of selecting one mode for taking the feature image from a plurality of modes based on a proportion of an area of the feature in a field of view in a specimen image that has been taken, and

[0026] a step of taking the feature image in the selected mode,

[0027] The plurality of modes include:

[0028] a first mode in which a specimen is scanned at a first scanning speed to take a specimen image, and the taken specimen image is cropped to take the feature image, and

[0029] a second mode in which the specimen is scanned at a second scanning speed faster than the first scanning speed to take a specimen image, and an area of the feature in the taken specimen image is scanned at a third scanning speed slower than the second scanning speed to take the feature image.

[0030] In such a resolution method, the acquisition time of the characteristic image can be shortened. BRIEF DESCRIPTION OF DRAWINGS

[0031] Fig. 1 is a view showing one example of the configuration of an electron microscope of Embodiment 1.

[0032] Fig. 2 is a view showing one example of the configuration of a particle resolution apparatus.

[0033] Fig. 3 is a view for explaining the first mode.

[0034] Fig. 4 is a view for explaining the second mode.

[0035] Fig. 5 is a view for explaining a particle resolution method.

[0036] Fig. 6 is a view for explaining a particle resolution method.

[0037] Fig. 7 is a view for explaining a particle resolution method.

[0038] Fig. 8 is a flowchart showing one example of the flow of a particle resolution process of a particle resolution apparatus.

[0039] Fig. 9 is a view for explaining a particle resolution method.

[0040] Fig. 10 is a view for explaining a particle resolution method.

[0041] Fig. 11 is a view for explaining a particle resolution method.

[0042] Fig. 12 is a view for explaining a particle resolution method.

[0043] Fig. 13 is a view for explaining a particle resolution method.

[0044] Fig. 14 is a view for explaining a particle resolution method.

[0045] Fig. 15 is a view for explaining the order of resolution of each region of a sample.

[0046] Explanation of reference numerals

[0047] 10…measurement section, 11…electron source, 12…condenser lens, 13…scanning deflector, 14…objective lens, 15…sample stage, 16…reflection electron detector, 17…secondary electron detector, 18…energy dispersive X-ray spectrometer, 19…wavelength dispersive X-ray spectrometer, 20…particle analysis device, 100…electron microscope, 200…processing section, 202…image acquisition section, 204…analysis section, 210…operation section, 220…display section, 230…storage section. DETAILED DESCRIPTION

[0048] Hereinafter, a preferred embodiment of the present application will be described in detail with reference to the drawings. Furthermore, the embodiment described below is not intended to unduly limit the scope of the present application described in the claims. In addition, all the configurations described below are not necessarily essential components of the present application.

[0049] In addition, hereinafter, as the charged particle beam device of the present application, a scanning electron microscope that images a sample by scanning the sample with an electron beam will be described as an example. Furthermore, the charged particle beam device of the present application can also be a device that images a sample by scanning the sample with a charged particle beam other than an electron beam (ion beam, etc.).

[0050] 1. First Embodiment

[0051] 1.1. Configuration of Electron Microscope

[0052] First, the electron microscope of the first embodiment will be described with reference to the drawings. Fig. 1 is a view showing one example of the configuration of the electron microscope 100 of the first embodiment.

[0053] As shown in Fig. 1 , the electron microscope 100 includes a measurement section 10 and a particle analysis device 20.

[0054] The measurement section 10 images a sample image by detecting electrons generated from a sample S by scanning the sample S with an electron beam EB. The sample image is an image obtained by scanning the sample S with a probe formed by the electron beam EB, etc. and detecting a signal (electron, X-ray, etc.) generated from the sample S. The sample image includes a secondary electron image, a reflection electron image.

[0055] The measurement section 10 includes an electron source 11, a condenser lens 12, a scanning deflector 13, an objective lens 14, a sample stage 15, a reflection electron detector 16, a secondary electron detector 17, an energy dispersive X-ray spectrometer 18, and a wavelength dispersive X-ray spectrometer 19.

[0056] The electron source 11 emits an electron beam EB. The electron source 11 is, for example, an electron gun that accelerates and emits an electron beam EB from an electron emitted from a cathode at an anode.

[0057] The condenser lens 12, together with the objective lens 14, converges the electron beam EB emitted from the electron source 11 to form an electron probe. By the condenser lens 12, the opening angle of the electron beam EB can be adjusted.

[0058] The scanning deflector 13 two-dimensionally deflects the electron beam EB. By deflecting the electron beam EB by the scanning deflector 13, the electron probe can be scanned over the sample S.

[0059] The objective lens 14 is a lens configured immediately in front of the sample S for forming an electron probe. The objective lens 14, for example, includes a coil and a yoke. In the objective lens 14, by enclosing magnetic lines of force generated by the coil in the yoke made of a material having high magnetic permeability, a portion of the yoke is made to have a notch to cause the magnetic lines of force distributed at high density to leak onto the optical axis.

[0060] The sample stage 15 places the sample S. The sample stage 15 supports the sample S. The sample stage 15 has a driving mechanism for moving the sample S. By the movement of the sample stage 15, the irradiation position of the electron beam EB on the sample S can be moved.

[0061] The reflected electron detector 16 detects reflected electrons generated at the sample S by irradiating the electron beam EB to the sample S. The reflected electron is an electron flying out in the process of the electron incident to the sample S being scattered by the elements constituting the sample S. The reflected electron detector 16, for example, is disposed immediately below the objective lens 14. The reflected electron detector 16 has a circular ring shape, and the electron beam EB is irradiated to the sample S through a hole in the center of the reflected electron detector 16. The reflected electron detector 16, for example, is a silicon semiconductor detector.

[0062] The secondary electron detector 17 detects secondary electrons released from the sample S by irradiating the electron beam EB to the sample S. The secondary electron is an electron excited in a solid by non-elastic scattering of incident electrons and released into a vacuum. The secondary electron detector 17, for example, is an ET detector (Everhart-Thornley detector).

[0063] The energy dispersive X-ray spectrometer (EDS) 18 is a detector for energy-resolving X-rays and obtaining a spectrum. The energy dispersive X-ray spectrometer 18 detects characteristic X-rays generated at the sample S by irradiating the electron beam EB to the sample S. Thereby, an EDS spectrum can be obtained.

[0064] The wavelength dispersive X-ray spectrometer 19 (WDS: Wavelength-Dispersive X-ray Spectrometer) separates and detects X-rays of a specific wavelength using Bragg reflection of X-rays by a spectrometer crystal. The wavelength dispersive X-ray spectrometer 19 acquires a spectrum of each wavelength using Bragg reflection by a spectrometer crystal with respect to characteristic X-rays generated in the sample S by irradiation of the electron beam EB to the sample S.

[0065] The particle analysis device 20 performs particle analysis. That is, the particle analysis device 20 captures a plurality of sample images from a plurality of regions of the sample S, acquires a particle image of a particle included in the sample S from each of the plurality of sample images, and acquires information of the particle based on the particle image. The information of the particle includes, for example, information of a shape of the particle such as a size of the particle, and information of a position of the particle. In addition, the particle analysis device 20 performs EDS analysis or WDS analysis on the particle based on the information of the position of the particle, and acquires information of a composition of the particle. The information of the particle includes the information of the composition of the particle.

[0066] Fig. 2 is a view showing one example of a configuration of the particle analysis device 20. As shown in Fig. 2 , the particle analysis device 20 includes a processing unit 200, an operation unit 210, a display unit 220, and a storage unit 230.

[0067] The operation unit 210 is used for a user to input operation information, and outputs the input operation information to the processing unit 200. The function of the operation unit 210 can be implemented by an input device such as a keyboard, a mouse, a button, a touch panel, a touch pad, and the like.

[0068] The display unit 220 displays an image generated by the processing unit 200. The function of the display unit 220 can be implemented by an LCD (Liquid Crystal Display), a touch panel type display, and the like.

[0069] The storage unit 230 stores programs, data, and the like used by the processing unit 200 to perform various calculation processes and various control processes. In addition, the storage unit 230 also functions as a work area of the processing unit 200, and is used to temporarily store calculation results and the like performed by the processing unit 200 according to various programs. The function of the storage unit 230 can be implemented by a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, and the like.

[0070] The functions of the processing unit 200 can be realized by executing programs stored in the storage unit 230 using various processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or a DSP (Digital Signal Processor). The processing unit 200 includes an image acquisition unit 202 and an analysis unit 204 .

[0071] The image acquisition unit 202 acquires the sample image captured by the measurement unit 10 and acquires a particle image from the acquired sample image. The image acquisition unit 202 repeatedly performs the process of acquiring the sample image and the process of acquiring the particle image from the sample image to acquire a plurality of particle images.

[0072] The analyzing unit 204 acquires information on the particles based on the plurality of particle images acquired by the image acquiring unit 202 .

[0073] 1.2. Method of obtaining particle images

[0074] 1.2.1. Particle image acquisition mode

[0075] The electron microscope 100 has a first mode and a second mode as modes for acquiring particle images.

[0076] 1.2.2. Mode 1

[0077] Fig. 3 This is a diagram for explaining the first mode.

[0078] In the first mode, the sample S is first scanned at the first scanning speed in the measurement unit 10 to capture a sample image Is. The first scanning speed is set to a scanning speed that allows confirmation of the particle shape. The scanning speed is the speed at which the electron probe scans, and the shorter the dwell time per pixel, the faster the scanning speed. For example, in the first mode, a 1024×768 pixel sample image is captured at a scanning speed with a dwell time per pixel of 4 μs / pixel. Furthermore, the first scanning speed can be appropriately changed depending on the accuracy required for particle analysis.

[0079] The electron probe scans the sample S using raster scanning. Specifically, the electron probe scans the sample S by repeatedly drawing a scan line in the +X direction, moving the scan line position in the -Y direction perpendicular to the +X direction, and then drawing a scan line in the +X direction.

[0080] Next, the particle image Ip is obtained by image processing to crop the region of the particle from the sample image Is. For example, first, the sample image Is is binarized, and the outline of the particle is detected from the binarized sample image Is. Thus, the region of the particle can be extracted from the sample image Is. Next, the particle image Ip can be generated by cutting out a region from the sample image Is, which contains the extracted region of the particle. In this way, the particle image Ip can be obtained by the first mode.

[0081] 1.2.3. Second Mode

[0082] Fig. 4 is a view for explaining the second mode.

[0083] In the second mode, first, the sample S is scanned at a second scan speed faster than the first scan speed in the measurement section 10 to take the sample image Is. The second scan speed is set to a speed at which the particle can be confirmed. For example, in the second mode, the sample image of 1024 x 768 pixels is taken at a scan speed of 1 μs / pixel per 1 pixel of dwell time. Further, the second scan speed can be appropriately changed depending on the accuracy required for particle analysis.

[0084] Next, the region of the particle is detected by image processing in the sample image Is, and in the measurement section 10, the region of the particle is scanned at a third scan speed slower than the second scan speed to take the particle image Ip, which contains the region of the particle. The third scan speed is, for example, the same as the first scan speed. For example, in the second mode, the particle image Ip is taken at a scan speed of 4 μs / pixel per 1 pixel of dwell time. Further, the third scan speed is not particularly limited as long as it is slower than the second scan speed, and can be slower than the first scan speed or faster than the first scan speed. In this way, the particle image Ip can be obtained by the second mode.

[0085] 1.2.4. Obtaining Time of Particle Image

[0086] In the first mode, if the number of pixels (resolution) of the sample image Is is R, and the dwell time per 1 pixel is D, the taking time of the sample image Is is represented by the product RxD of the number of pixels R and the dwell time D. Further, the time to crop the sample image Is to obtain the particle image Ip is extremely short compared to the taking time, and thus can be ignored. Therefore, the obtaining time to obtain the particle image Ip by the first mode is represented by the product RxD.

[0087] In the second mode, if the dwell time per 1 pixel at the time of capturing the test image Is is set to Dl, the capturing time of the test image Is is represented by the product RxDl of the number of pixels R and the dwell time Dl. In addition, if the number of pixels of the region of the particle in the test image Is is set to S and the dwell time per 1 pixel is set to D2, the capturing time of the particle image Ip is represented by the product SxD2 of the number of pixels S of the region of the particle and the dwell time D2. Therefore, the acquisition time of the particle image in the second mode is represented by RxDl+SxD2.

[0088] The acquisition time of the particle image Ip in the second mode is shorter than the acquisition time of the particle image Ip in the first mode, or the acquisition time of the particle image Ip in the first mode is shorter than the acquisition time of the particle image Ip in the second mode, depending on the proportion of the region of the particle in the field of view in the test image Is.

[0089] The proportion of the particle in the field of view can be represented by the number of pixels S of the region of the particle in the test image Is, for example, while the resolution of the test image Is is constant. Therefore, if the number of pixels S of the region of the particle is less than a prescribed number, the acquisition time RxDl+SxD2 of the particle image Ip in the second mode is shorter than the acquisition time RxD of the particle image Ip in the first mode. In addition, if the number of pixels S of the region of the particle is more than the prescribed number, the acquisition time RxD of the particle image Ip in the first mode is shorter than the acquisition time RxDl+SxD2 of the particle image Ip in the second mode. Therefore, by switching the mode depending on the number of pixels S of the region of the particle, the acquisition time of the particle image Ip can be shortened.

[0090] In the case where the acquisition time RxD of the particle image Ip in the first mode is shorter than the acquisition time RxDl+SxD2 of the particle image Ip in the second mode, RxD

[0091] In this case, the proportion of the particle in the field of view in the area to be photographed next, i.e., the area before photographing, cannot be known. Therefore, the proportion of the particle in the field of view in the area to be photographed next is estimated from the specimen image Is that has been acquired. Specifically, the average number of pixels of the area of the particle in the specimen image is calculated, and the average number of pixels is compared with a threshold value, to select the acquisition mode of the area to be photographed next.

[0092] 1.3. Particle analysis method

[0093] Figs. 5 to 7 is a diagram for explaining the particle analysis method. In Figs. 5 to 7 , the X-axis and the Y-axis that are orthogonal to each other are illustrated.

[0094] In the particle analysis, as Fig. 5 indicated, analysis is performed in the order of the area S-2, the area S-3, and the area S-4 in the +X direction from the area S-1 of the 1st column. After analysis is performed up to the last area S-4 of the 1st column, movement is made in the -Y direction, and analysis is performed in the order in the +X direction from the first area S-5 of the 2nd column. For the areas after the 3rd column, analysis is also performed in the same order. In this way, analysis is performed from the area S-1 to the area S-n (n is an integer of 2 or more).

[0095] First, analysis of the area S-1 of the specimen S is performed. In the area S-1, since there is no specimen image that has been acquired, the particle image Ip-1 is acquired in the 1st mode that is initially set. Next, information of the position (coordinates) of the particle and information of the shape of the particle are acquired from the particle image Ip-1 through image processing. Next, EDS analysis is performed on the particle, and information of the composition of the particle is acquired. Through the above procedures, information of the particle of the area S-1 can be acquired. Further, in the above, the initial setting is the 1st mode, and the particle image Ip-1 of the area S-1 is acquired in the 1st mode, but the initial setting can be the 2nd mode, and the particle image Ip-1 of the area S-1 can be acquired in the 2nd mode.

[0096] Next, as Fig. 6 indicated, analysis of the area S-2 of the specimen S is performed. First, the mode of acquiring the particle image Ip-2 of the area S-2 is selected. The selection of the mode is performed based on the proportion of the area of the particle in the field of view in the specimen image that has been acquired. In this case, the average number of pixels of the area of the particle in the specimen image is used as the proportion of the particle in the field of view. The number of pixels of the area of the particle in the specimen image is obtained by detecting the outline of the particle from the particle image Ip-1 using image processing and counting the number of pixels within the outline.

[0097] As Fig. 6As shown, the sample image has been acquired only in the region S-1, and therefore, as the average number of pixels S, the number of pixels of the region of the particles in the region S-1 is used. In a case where the average number of pixels S of the acquired sample image is greater than the threshold value (R x (D - D1)) / D2, the sample image Is-2 is acquired in the first mode. In a case where the average number of pixels S is equal to or less than the threshold value, the sample image Is-2 is acquired in the second mode.

[0098] Next, as with the region S-1, the information of the position of the particles and the information of the shape of the particles are acquired from the acquired particle image Ip-2 by image processing, the particles are subjected to EDS analysis, and the information of the composition of the particles is acquired. Through the above procedures, the information of the particles in the region S-2 can be acquired.

[0099] Next, as shown in Fig. 7 the region S-3 of the sample S is analyzed. First, the mode of acquiring the particle image Ip-3 of the region S-3 is selected. In the selection of the mode, first, the number of pixels of the region of the particles in the acquired sample image Is-1 and the number of pixels of the region of the particles in the sample image Is-2 are calculated, and the average number of pixels S is calculated. Then, in a case where the average number of pixels S is greater than the threshold value, the particle image Ip-3 is acquired in the first mode. In a case where the average number of pixels S is equal to or less than the threshold value, the particle image Ip-3 is acquired in the second mode. In this way, the mode can be selected. Next, as with the regions S-1 and S-2, the information of the position of the particles and the information of the shape of the particles are acquired from the acquired particle image Ip-3 by image processing, and the information of the composition of the particles is acquired by EDS analysis. Through the above procedures, the information of the particles in the region S-3 can be acquired.

[0100] For example, in a case where the analysis of the region S-m (m is an integer of 2 or more) is performed, in each of the acquired sample image Is-1, the sample image Is-2,..., and the sample image Is-(m-1), the number of pixels of the region of the particles is calculated, and the average number of pixels S is calculated. Then, in a case where the average number of pixels S is greater than the threshold value, the particle image Ip-m is acquired in the first mode. In a case where the average number of pixels S is equal to or less than the threshold value, the particle image Ip-m is acquired in the second mode. Next, the information of the position of the particles and the information of the shape of the particles are acquired from the acquired particle image Ip-m by image processing, and the information of the composition of the particles is acquired by EDS analysis. Through the above procedures, the information of the particles in the region S-m can be acquired. In this way, the analysis is performed up to the region S-n.

[0101] 1.4. Processing

[0102] Fig. 8 is a flowchart showing one example of the flow of the particle analysis processing of the particle analysis apparatus 20.

[0103] Here, the region of the sample S that is to be the analysis target is set in advance by the user. The image acquisition section 202 divides the region to be the analysis target by each scanning range of the electron beam, and determines the region to be analyzed in one time. Here, the image acquisition section 202 divides the region to be the analysis target into n regions, and analyzes in order from the region S-1 (N=l) to the region S-n (N=n).

[0104] When the user inputs an instruction to start particle analysis to the particle analysis apparatus 20 via the operation section 210, the image acquisition section 202 sets N=l, and acquires the particle image Ip-1 in the region S-1 of the sample S in the first mode (step S100). The image acquisition section 202 scans the region S-1 of the sample S at the first scanning speed to acquire the sample image Is-1. Next, the image acquisition section 202 acquires the particle image Ip-1 by detecting the region of the particle from the sample image Is-1, and cropping the region of the particle from the sample image Is-1.

[0105] Next, the analysis section 204 acquires information of the position of the particle and information of the shape of the particle by performing image processing on the acquired particle image Ip-1 (step S102).

[0106] Next, the analysis section 204 acquires information of the composition of the particle from the result of the EDS analysis in the measurement section 10 (step S104). The analysis section 204 determines the particle in the sample S from the information of the position of the particle, and causes the measurement section 10 to irradiate the particle in the sample S with the electron beam EB. The characteristic X-rays emitted from the particle by the irradiation with the electron beam EB are detected by the energy dispersive X-ray spectrometer 18, and an EDS spectrum is obtained. Thus, the analysis section 204 acquires the EDS spectrum. The analysis section 204 performs qualitative analysis and quantitative analysis on the EDS spectrum, and acquires the information of the composition of the particle.

[0107] Further, here, the case where the analysis section 204 performs EDS analysis is described, but the analysis section 204 can perform WDS analysis to acquire the information of the composition of the particle. In addition, the analysis section 204 can perform both EDS analysis and WDS analysis to acquire the information of the composition of the particle.

[0108] Next, the image acquisition section 202 determines whether or not the analysis of the last region S-n of the region of the sample S that is to be the analysis target has ended, that is, whether or not N=n is satisfied (step S106).

[0109] The image acquisition section 202, in the case where it is determined that the analysis of the last region S-n is not ended, that is, in the case where it is determined that N=n is not satisfied (NO in step S106), sets N=N+l, and moves the sample stage 15 to move the scanning range from the region S-1 to the region S-2 (step S108).

[0110] Next, the image acquisition section 202 calculates the number of pixels S of the region of the particle in the already-acquired sample image Is-1 (step S110). The image acquisition section 202 detects the outline of the particle in the sample image Is-1, and counts the number of pixels within the detected outline. Here, the already-acquired sample image Is-1 is only the sample image Is-1, and thus the number of pixels of the region of the particle in the sample image Is-1 is used as the average number of pixels S. Next, the image acquisition section 202 determines whether the average number of pixels S is larger than the threshold value (R x (D - D1)) / D2 (step S112).

[0111] The image acquisition section 202 acquires the particle image Ip-2 in the first mode when it is determined that the average number of pixels S is larger than the threshold value (YES in step S112) (step S114). The image acquisition section 202 causes the measurement section 10 to scan the sample S at the first scan speed to shoot the sample image Is-2, and acquires the particle image Ip-2 by cropping the shot sample image Is-2.

[0112] In addition, the image acquisition section 202 acquires the particle image Ip-2 in the second mode when it is determined that the average number of pixels S is equal to or smaller than the threshold value (NO in step S112) (step S116). The image acquisition section 202 causes the measurement section 10 to scan the sample S at the second scan speed to shoot the sample image Is-2. Next, the image acquisition section 202 detects the region of the particle in the shot sample image Is-2 by image processing, and causes the measurement section 10 to scan the region of the particle in the sample S at the third scan speed slower than the second scan speed to shoot the particle image Ip-2 based on the detection result. Thus, the image acquisition section 202 acquires the particle image Ip-2.

[0113] After the particle image Ip-2 is acquired in the first mode (after step S114) or after the particle image Ip-2 is acquired in the second mode (after step S116), the process returns to step S102, and the analysis section 204 acquires information of the position of the particle and information of the shape of the particle by image processing with respect to the particle image Ip-2 (step S102). Next, the analysis section 204 acquires information of the composition of the particle from the result of the EDS analysis in the measurement section 10 (step S104).

[0114] The image acquisition section 202 determines whether the analysis of the last region S-n has ended (step S106), and when it is determined that the analysis of the last region S-n has not ended (NO in step S106), sets N = N + 1, moves the sample stage 15 to move the sample S, and moves the scan range from the region S-2 to the region S-3 (step S108).

[0115] The image acquisition unit 202 calculates the number of pixels of the region of the particle in the specimen image Is-1 that has been acquired and the number of pixels of the region of the particle in the specimen image Is-2, calculates the average number of pixels S (step S110), and determines whether the average number of pixels S is greater than a threshold value (step S112). The image acquisition unit 202 acquires the particle image Ip-3 in the first mode in a case where it is determined that the average number of pixels S is greater than the threshold value (YES in step S112) (step S114). The image acquisition unit 202 acquires the particle image Ip-3 in the second mode in a case where it is determined that the average number of pixels S is equal to or less than the threshold value (NO in step S112) (step S116). The analysis unit 204 acquires information of the position of the particle and information of the shape of the particle from the particle image Ip-3 (step S102), and acquires information of the composition of the particle from the result of the EDS analysis (step S104).

[0116] The image acquisition unit 202 and the analysis unit 204 repeatedly perform the processes of step S108, step S110, step S112, step S114, step S116, step S102, step S104, and step S106 until it is determined that the analysis of the last region S-n has ended.

[0117] The image acquisition unit 202 ends the particle analysis process in a case where it is determined that the analysis of the last region S-n has ended (YES in step S106).

[0118] 1.5. Effects

[0119] The electron microscope 100 includes: the measurement unit 10 that photographs a specimen image by scanning the specimen S with the electron beam EB; the image acquisition unit 202 that acquires a plurality of specimen images Is photographed in a plurality of regions of the specimen S, acquires a particle image Ip of a particle included in the specimen S from each of the plurality of specimen images Is, and acquires information of the particle based on the particle image Ip; and the analysis unit 204. In addition, the image acquisition unit 202 repeatedly performs the following processes to acquire a plurality of particle images Ip: a process of selecting one mode from a plurality of modes for acquiring the particle image Ip based on a proportion of a region of the particle in the field of view in a specimen image Is that has been acquired; and a process of acquiring the particle image Ip in the selected mode. In addition, the plurality of modes include: a first mode of photographing a specimen image Is by scanning the specimen S at a first scanning speed, and acquiring the particle image Ip by cropping the photographed specimen image Is; and a second mode of photographing a specimen image Is by scanning the specimen S at a second scanning speed faster than the first scanning speed, and photographing the particle image Ip by scanning a region of the particle in the photographed specimen image Is at a third scanning speed slower than the second scanning speed.

[0120] Therefore, in the electron microscope 100, it is possible to shorten the time to acquire the particle image. Therefore, for example, in the electron microscope 100, it is possible to perform particle analysis in a short time. In addition, for example, in the electron microscope 100, by shortening the time to acquire the particle image, the measurement time for EDS analysis is lengthened, and thus it is possible to improve the accuracy of EDS analysis.

[0121] In the electron microscope 100, the image acquisition unit 202 calculates the average of the number of pixels of the region of the particle in the already-acquired sample image in the process of selecting the mode, and selects one mode from the plurality of modes on the basis of the average. Therefore, in the electron microscope 100, it is possible to accurately estimate the proportion of the region of the particle in the field of view. Therefore, in the electron microscope 100, it is possible to accurately select the acquisition mode, and shorten the time to acquire the particle image.

[0122] In the electron microscope 100, the image acquisition unit 202 calculates the number of pixels of the region of the particle in each of the already-acquired sample images in the process of selecting the mode, calculates the average number of pixels, and acquires the particle image in the first mode when the average number of pixels is greater than a threshold value. In addition, if the number of pixels of the sample image is R, the dwell time per 1 pixel when the sample image is captured in the first mode is D, the dwell time per 1 pixel when the sample image is captured in the second mode is D1, and the dwell time per 1 pixel when the particle image is captured in the second mode is D2, the threshold value is (R x (D - D1)) / D2. Therefore, in the electron microscope 100, it is possible to shorten the time to acquire the particle image.

[0123] In the electron microscope 100, the dwell time per 1 pixel of the electron beam EB when the sample image is captured in the second mode is shorter than the dwell time per 1 pixel of the electron beam EB when the sample image is captured in the first mode. Therefore, it is possible to make the second scan speed faster than the first scan speed.

[0124] The analysis method in the electron microscope 100 includes: a process of acquiring a plurality of sample images captured in a plurality of regions of the sample S; a process of acquiring a particle image including an image of a particle included in the sample S from each of the plurality of sample images; and a process of acquiring information of the particle based on the particle image. In addition, the process of acquiring the particle image repeatedly performs the following processes to acquire a plurality of particle images: a process of selecting one mode from a plurality of modes for acquiring the particle image based on a proportion of a region of the particle in the field of view in the already-acquired sample image; and a process of acquiring the particle image in the selected mode. In addition, the plurality of modes includes: a first mode of capturing a sample image by scanning the sample S at a first scanning speed, and acquiring a particle image by cropping the captured sample image; and a second mode of capturing a sample image by scanning the sample S at a second scanning speed faster than the first scanning speed, and capturing a particle image by scanning a region of the particle in the captured sample image at a third scanning speed slower than the second scanning speed.

[0125] Therefore, in the analysis method in the electron microscope 100, it is possible to shorten the acquisition time of the particle image.

[0126] 2. Second Embodiment

[0127] 2.1. Electron Microscope

[0128] Next, the electron microscope of the second embodiment will be described. The configuration of the electron microscope of the second embodiment is the same as that of the electron microscope 100 shown in the above-described Fig. 1 and Fig. 2 The description thereof will be omitted.

[0129] 2.2. Particle Analysis Method

[0130] Figs. 9 to 11 is a diagram for explaining the particle analysis method. Hereinafter, the differences from the example of the particle analysis method in the above-described first embodiment will be described, and the same will be omitted.

[0131] In the above-described first embodiment shown in Fig. 6 and Fig. 7 , the average number of pixels of the region of the particle is calculated in the already-acquired sample image, and the mode is selected depending on whether the average number of pixels is larger than a threshold value.

[0132] In contrast, in the second embodiment, in the case of capturing a sample image of a first region of the sample S, the average number of pixels of the region of the particle is calculated in an already-acquired sample image of a second region adjacent to the first region, and the mode is selected depending on whether the average number of pixels is larger than a threshold value. Hereinafter, the particle analysis method in the second embodiment will be described with reference to Figs. 9 to 11

[0133] ​First, the analysis of the region S-1 of the sample S is performed. The analysis of the region S-1 is performed in the same manner as in the first embodiment described above. Next, the analysis of the region S-2 of the sample S is performed. In the region S-2, the sample image of the adjacent region that has been acquired is only the sample image Is-1 of the region S-1. Therefore, the analysis of the region S-2 of the sample S is performed in the same manner as the process of performing the analysis of the region S-2 in the first embodiment described above.

[0134] Next, as shown in Fig. 6, the analysis of the region S-3 of the sample S is performed. In the region S-3, the sample image of the adjacent region that has been acquired is only the sample image Is-2. Therefore, the number of pixels of the region of the particle in the sample image Is-2 is calculated. Then, in a case where the average number of pixels S calculated is larger than the threshold value (R x (D - D1)) / D2, the particle image Ip-3 is acquired in the first mode, and in a case where the average number of pixels is equal to or smaller than the threshold value, the particle image Ip-3 is acquired in the second mode. Fig. 9 Next, the analysis of the region S-4 of the sample S is performed. In the region S-4, the sample image of the adjacent region that has been acquired is only the sample image Is-3. Therefore, the number of pixels of the region of the particle in the sample image Is-3 is calculated. Then, in a case where the average number of pixels S calculated is larger than the threshold value (R x (D - D1)) / D2, the particle image Ip-4 is acquired in the first mode, and in a case where the average number of pixels is equal to or smaller than the threshold value, the particle image Ip-4 is acquired in the second mode.

[0135] Next, as shown in Fig. 6, the analysis of the region S-3 of the sample S is performed. In the region S-3, the sample image of the adjacent region that has been acquired is only the sample image Is-2. Therefore, the number of pixels of the region of the particle in the sample image Is-2 is calculated. Then, in a case where the average number of pixels S calculated is larger than the threshold value (R x (D - D1)) / D2, the particle image Ip-3 is acquired in the first mode, and in a case where the average number of pixels is equal to or smaller than the threshold value, the particle image Ip-3 is acquired in the second mode.

[0136] Fig. 10 Next, as shown in Fig. 6, the analysis of the region S-3 of the sample S is performed. In the region S-3, the sample image of the adjacent region that has been acquired is only the sample image Is-2. Therefore, the number of pixels of the region of the particle in the sample image Is-2 is calculated. Then, in a case where the average number of pixels S calculated is larger than the threshold value (R x (D - D1)) / D2, the particle image Ip-3 is acquired in the first mode, and in a case where the average number of pixels is equal to or smaller than the threshold value, the particle image Ip-3 is acquired in the second mode.

[0137] Next, as shown in Fig. 6, the analysis of the region S-3 of the sample S is performed. In the region S-3, the sample image of the adjacent region that has been acquired is only the sample image Is-2. Therefore, the number of pixels of the region of the particle in the sample image Is-2 is calculated. Then, in a case where the average number of pixels S calculated is larger than the threshold value (R x (D - D1)) / D2, the particle image Ip-3 is acquired in the first mode, and in a case where the average number of pixels is equal to or smaller than the threshold value, the particle image Ip-3 is acquired in the second mode. Fig. 11 ​As shown, the analysis of the region S-6 of the sample S is performed. In the region S-6, four sample images, i.e., the sample image Is-1, the sample image Is-2, the sample image Is-3, and the sample image Is-5, which are adjacent to the region S-6, have been acquired. Therefore, in each of the four sample images, the number of pixels of the region of the particle is calculated, and the average number of pixels S is found. Then, in a case where the calculated average number of pixels S is larger than a threshold value (R x (D - D1)) / D2, the particle image Ip-6 is acquired in the first mode, and in a case where the average number of pixels S is equal to or smaller than the threshold value, the particle image Ip-6 is acquired in the second mode. In this way, the analysis is performed from the region S-1 to the region S-n.

[0138] 2.3. Processing

[0139] The particle analysis processing in the electron microscope 100 of the second embodiment is the same as the particle analysis processing in the electron microscope 100 of the first embodiment except for the processing of calculating the average number of pixels S of the region of the particle shown in the step S110. Hereinafter, the difference from the example of the particle analysis method in the first embodiment described above will be described, and the same will be omitted. Fig. 8

[0140] In the step S110, in a case where the sample image of the first region of the sample S is captured, the image acquisition section 202 calculates the average number of pixels S of the region of the particle in the sample image of the second region, which is adjacent to the first region, that has been acquired, and determines whether the average number of pixels S is larger than a threshold value. Then, the image acquisition section 202 acquires the particle image in the first mode in a case where the average number of pixels S is larger than the threshold value, and acquires the particle image in the second mode in a case where the average number of pixels S is equal to or smaller than the threshold value.

[0141] 2.4. Effects

[0142] In the electron microscope 100, the image acquisition section 202 calculates, in the processing of selecting the mode, the average value of the number of pixels of the region of the particle in the sample image of the second region, which is adjacent to the first region, that has been acquired, in a case where the sample image of the first region of the sample S is captured, and selects one mode from the plurality of modes on the basis of the average value. Therefore, in the electron microscope 100, the proportion of the region of the particle in the field of view can be accurately estimated. Thus, in the electron microscope 100, the acquisition mode can be accurately selected, and the time of acquisition of the particle image can be shortened.

[0143] 3. Third Embodiment

[0144] 3.1. Electron Microscope

[0145] Next, the electron microscope of the third embodiment will be described. The configuration of the electron microscope of the third embodiment is the same as that of the electron microscope of the first embodiment described above except for the processing of calculating the average number of pixels S of the region of the particle shown in the step S110. Fig. 1 ​and Fig. 2 The structure of the electron microscope 100 shown is the same, and its description is omitted.

[0146] 3.2. Particle analysis method

[0147] Figs. 12 to 14 1 and 2 are diagrams for explaining a particle analysis method. Hereinafter, differences from the example of the particle analysis method in the first embodiment described above will be described, and descriptions of the same points will be omitted.

[0148] In the above Fig. 6 and Fig. 7 In the first embodiment shown, the average number of pixels S of the particle region in the acquired sample image is calculated, and a mode is selected based on whether the average number of pixels S is larger than a threshold value.

[0149] In contrast, in the third embodiment, when a sample image of the second region is captured following a sample image of the first region, if the sample image of the first region and the sample image of the second region are adjacent to each other, the number of pixels in the region of particles is calculated in the sample image of the first region, and a mode is selected based on whether this number of pixels is greater than a threshold value. In other words, the number of pixels in the region of particles is calculated in the sample image captured immediately before, and this number of pixels is compared with the threshold value to select a mode.

[0150] On the other hand, when the sample image of the first area is not adjacent to the sample image of the second area, the number of pixels of the particle area is calculated in the sample image of the third area adjacent to the second area, and the mode is selected based on whether the number of pixels is larger than the threshold.

[0151] First, the area S-1 of the sample S is analyzed. The analysis of the area S-1 is performed in the same manner as in the first embodiment described above. Next, the area S-2 of the sample S is analyzed. In the area S-2, the area that was photographed just before is the area S-1. Therefore, the number of pixels of the particle area is calculated in the sample image Is-1. Then, when the calculated number of pixels S is greater than the threshold value (R×(D-D1)) / D2, the particle image Ip-2 is obtained in the first mode, and when the number of pixels S is less than the threshold value, the particle image Ip-2 is obtained in the second mode.

[0152] Then, if Fig. 12 As shown, analysis is performed on region S-3. Within region S-3, the area captured immediately before is region S-2. Therefore, the number of pixels in the particle region is calculated in sample image Is-2. If the calculated number of pixels S is greater than the threshold (R × (D - D1)) / D2, particle image Ip-3 is acquired using the first mode. If the number of pixels S is below the threshold, particle image Ip-3 is acquired using the second mode.

[0153] Then, if Fig. 13As shown, analysis is performed on area S-4. The area captured immediately before in area S-4 is area S-3. Therefore, the number of pixels in the particle area is calculated in sample image Is-3. If the calculated number of pixels S is greater than the threshold (R×(D-D1)) / D2, particle image Ip-4 is acquired using the first mode. If the number of pixels is below the threshold, particle image Ip-4 is acquired using the second mode.

[0154] Then, if Fig. 14 As shown, the analysis of area S-5 is performed. In area S-5, the area photographed just before is area S-4. However, area S-4 is located at the end of the area to be analyzed in the +X direction, and area S-5 is located at the end of the -X direction. That is, area S-4 and area S-5 are not adjacent. In this case, the number of pixels S of the particle area is calculated in the sample image Is-1 of area S-1 adjacent to area S-5. Then, when the calculated number of pixels S is greater than the threshold value (R×(D-D1)) / D2, the particle image Ip-5 is obtained in the first mode, and when the number of pixels S is less than the threshold value, the particle image Ip-5 is obtained in the second mode.

[0155] Here, as a region adjacent to region S-5, region S-1, whose side adjacent to region S-5 is the longest, is selected. Alternatively, as a region adjacent to region S-5, the number of pixels in the particle region can be calculated in the sample images obtained for all regions adjacent to region S-5, thereby calculating the average number of pixels. For example, in region S-5, region S-1 is adjacent to region S-2. Therefore, the number of pixels in the particle region in sample image Is-1 and the number of pixels in the particle region in sample image Is-2 can also be calculated to calculate the average number of pixels.

[0156] 3.3. Processing

[0157] The particle analysis process in the electron microscope 100 of the third embodiment is Fig. 8 Except for the difference in the process of calculating the average number of pixels S in the particle area shown in step S110, the particle analysis process is the same as the particle analysis process in the electron microscope 100 of the first embodiment. The following describes the differences from the example of the particle analysis method in the first embodiment described above, and the description of the same points is omitted.

[0158] In step S110, in a case where the image taking section 202 takes the sample image of the 2nd region after the sample image of the 1st region, when the sample image of the 1st region is adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle is calculated in the sample image of the 1st region, and the mode is selected depending on whether the number of pixels is larger than the threshold value. In addition, when the sample image of the 1st region is not adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle is calculated in the sample image of the 3rd region adjacent to the 2nd region, and the mode is selected depending on whether the number of pixels is larger than the threshold value.

[0159] 3.4. Effects

[0160] In the electron microscope 100, in the process of selecting the mode, in a case where the image taking section 202 takes the sample image of the 2nd region after the sample image of the 1st region, when the sample image of the 1st region is adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle is calculated in the sample image of the 1st region, and the mode is selected depending on whether the number of pixels is larger than the threshold value. In addition, when the sample image of the 1st region is not adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle is calculated in the sample image of the 3rd region adjacent to the 2nd region, and the mode is selected depending on whether the number of pixels is larger than the threshold value. Therefore, in the electron microscope 100, the proportion of the region of the particle in the field of view can be accurately estimated. Thus, in the electron microscope 100, the mode can be accurately selected, and the time of taking the particle image can be shortened.

[0161] 3.5. Modification

[0162] In the above-described 3rd embodiment, in a case where the image taking section 202 takes the sample image of the 2nd region after the sample image of the 1st region, when the sample image of the 1st region is not adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle is calculated in the sample image of the 3rd region adjacent to the 2nd region, but even when the sample image of the 1st region is not adjacent to the sample image of the 2nd region, the number of pixels of the region of the particle can be calculated in the sample image of the 1st region. That is, in the process of selecting the mode, in a case where the image taking section 202 takes the sample image of the 2nd region after the sample image of the 1st region, the number of pixels of the region of the particle can always be calculated in the sample image of the 1st region, and the mode can be selected depending on whether the number of pixels is larger than the threshold value.

[0163] 4. Modification

[0164] 4.1. 1st Modification

[0165] In the above-described first to third embodiments, the dwell time of the electron beam per 1 pixel at the time of capturing the specimen image in the second mode is shorter than the dwell time of the electron beam per 1 pixel at the time of capturing the specimen image in the first mode. Therefore, the second scan speed at the time of capturing the specimen image in the second mode is faster than the first scan speed at the time of capturing the specimen image in the first mode.

[0166] In relation to this, the dwell time of the electron beam per 1 pixel can also be made constant, and the resolution of the specimen image in the second mode can be made lower than the resolution of the specimen image in the first mode. Thereby, the second scan speed at the time of capturing the specimen image in the second mode can be made faster than the first scan speed at the time of capturing the specimen image in the first mode. The resolution of the specimen image corresponds to the number of pixels of the specimen image. The scan speed is inversely proportional to the resolution (number of pixels) of the specimen image. Therefore, by making the resolution of the specimen image lower, that is, by making the number of pixels of the specimen image smaller, the scan speed can be increased. The resolution of the specimen image in the second mode is, for example, set to a resolution at which the particles can be confirmed. Further, the resolution of the specimen image in the second mode can be appropriately changed according to the accuracy required for particle analysis.

[0167] The resolution of the particle image in the second mode is higher than the resolution of the specimen image in the second mode. The resolution of the particle image in the second mode can be the same as the resolution of the specimen image in the first mode, or can be higher than the resolution of the specimen image in the first mode.

[0168] 4.2. Second Modified Example

[0169] In the above-described first to third embodiments, the information of the particles included in the specimen S is acquired from the particle image acquired from the specimen image. That is, the particles included in the specimen S are taken as the object of analysis, but the object of analysis is not limited to the particles.

[0170] For example, in the electron microscope 100, the information of the characteristic object included in the specimen S can also be acquired from the characteristic image acquired from the specimen image. The characteristic object can be, for example, a defect such as a crystal defect, or an inclusion in steel. These defects and inclusions are captured in the specimen image such as the secondary electron image and the reflection electron image with a contrast different from the base material of the specimen S, like the particles. Therefore, the characteristic object such as the defect and the inclusion can be extracted from the specimen image by image processing, like the particles described above. Thus, the characteristic object such as the defect and the inclusion can be analyzed in the same manner as the particle analysis described above.

[0171] 4.3. Third Modified Example

[0172] Fig. 15 is a view for explaining the order of analysis of each region of the specimen S.

[0173] In the above-described first to third embodiments, as described above,Fig. 5 As shown, after sequentially analyzing the regions of the first column in the +X direction, the regions of the second column are sequentially analyzed in the +X direction by moving in the -Y direction. The regions of the sample S to be analyzed are sequentially analyzed in the same order for the third column and thereafter.

[0174] In the third modification, as shown in FIG. 9, after sequentially analyzing the regions of the first column in the +X direction, the regions of the second column are sequentially analyzed in the -X direction by moving in the -Y direction. After the analysis of the regions of the second column is performed, the regions of the third column are sequentially analyzed in the +X direction by moving in the -Y direction. The regions of the sample S to be analyzed are sequentially analyzed in the same order for the fourth column and thereafter. Fig. 15

[0175] In addition, the order in which the regions of the sample S are analyzed is not limited to the examples shown in FIGS. 8 and 9, and the regions can be analyzed in any order. Fig. 5 Fig. 15

[0176] 4.4. Fourth Modification

[0177] In the first embodiment described above, the average value (average number of pixels S) of the number of pixels of the regions of the particles in the plurality of sample images that have been acquired is compared with the threshold value, but the representative value of the number of pixels of the regions of the representative particles is not limited to the average value. For example, a central value or a mode value of the number of pixels of the regions of the particles can be compared with the threshold value as the representative value.

[0178] 4.5. Fifth Modification

[0179] In the first to third embodiments described above, the charged particle beam device of the present application is described as a scanning electron microscope, but the charged particle beam device of the present application is not limited to a scanning electron microscope. The charged particle beam device of the present application can be, for example, a scanning transmission electron microscope (STEM), an electron probe microanalyzer (EPMA), a focused ion beam device (FIB), or the like. That is, the charged particle beam device of the present application is not particularly limited as long as it is a device that can capture a sample image by scanning a sample with a charged particle beam such as an electron beam or an ion beam.

[0180] In addition, the embodiments and modifications described above are one example and are not limited thereto. For example, the embodiments and the modifications can be appropriately combined.

[0181] ​​​The present application is not limited to the above-described embodiments, and various modifications can be made. For example, the present application includes configurations substantially the same as those described in the embodiments. By substantially the same, for example, configurations having the same functions, methods, and results, or configurations having the same objects and effects are meant. In addition, the present application includes configurations in which non-essential parts among the configurations described in the embodiments are replaced. In addition, the present application includes configurations that have the same effects as the configurations described in the embodiments or configurations that can achieve the same objects. In addition, the present application includes configurations to which publicly known technologies are added to the configurations described in the embodiments.

Claims

1. A charged particle beam device, characterized in that Include: a measuring unit that scans a sample with a charged particle beam to capture an image of the sample; an image acquisition unit that acquires a plurality of sample images captured in a plurality of regions of the sample, and acquires a characteristic image from each of the plurality of sample images, the characteristic image being an image of a characteristic object included in the sample; and an analyzing unit that obtains information about the feature object based on the feature image, The image acquisition unit repeatedly performs the following processing to acquire a plurality of characteristic images: A process of selecting one mode from a plurality of modes for acquiring the characteristic image based on the ratio of the region of the characteristic object in the field of view in the already acquired sample image; and Acquiring the feature image in the selected mode, The multiple modes include: a first mode of scanning the sample at a first scanning speed to capture a sample image, and cropping the captured sample image to obtain the characteristic image; as well as The second mode scans the sample at a second scanning speed faster than the first scanning speed to capture a sample image, and scans the region of the characteristic object in the captured sample image at a third scanning speed slower than the second scanning speed to capture the characteristic image.

2. The charged particle beam device according to claim 1, wherein The image acquisition unit is processing in the selection mode. Calculate the representative value of the ratio in the sample image that has been obtained, Based on the representative value, one pattern is selected from the plurality of patterns.

3. The charged particle beam device according to claim 2, wherein: The image acquisition unit is processing in the selection mode. The number of pixels in the region of the characteristic object is obtained in each sample image obtained, and the average number of pixels is calculated. When the average number of pixels is greater than a threshold value, the characteristic image is acquired in the first mode. If the number of pixels of the sample image is set to R, the dwell time of each pixel when the sample image is photographed in the first mode is set to D, the dwell time of each pixel when the sample image is photographed in the second mode is set to D1, and the dwell time of each pixel when the feature image is photographed in the second mode is set to D2, then the threshold value is (R×(D-D1)) / D2.

4. The charged particle beam device according to claim 1, wherein The image acquisition unit is processing in the selection mode. When a sample image of a first area of ​​the sample is captured, a representative value of the ratio is calculated in a sample image of a second area adjacent to the first area that has already been captured. Based on the representative value, one pattern is selected from the plurality of patterns. The charged particle beam device according to claim 1 , wherein: The image acquisition unit is processing in the selection mode. When a sample image of a second region is captured subsequent to a sample image of a first region, the ratio is calculated in the sample image of the first region. One mode is selected from the plurality of modes based on the ratio in the sample image of the first region. The charged particle beam device according to claim 1 , wherein: When the image acquisition unit captures the sample image of the second area after the sample image of the first area in the process of the selection mode, When the first area is adjacent to the second area, the ratio is calculated in the sample image of the first area, and one mode is selected from the plurality of modes based on the ratio in the sample image of the first area. When the first region and the second region are not adjacent to each other, the ratio is calculated in a sample image of a third region adjacent to the second region, and one mode is selected from the plurality of modes based on the ratio in the sample image of the third region.

7. The charged particle beam device according to any one of claims 1 to 6, wherein: The residence time of the charged particle beam per pixel when capturing the sample image in the second mode is shorter than the residence time of the charged particle beam per pixel when capturing the sample image in the first mode.

8. The charged particle beam device according to any one of claims 1 to 6, wherein The resolution of the sample image in the second mode is lower than the resolution of the sample image in the first mode.

9. An analysis method using a charged particle beam device that scans a sample with a charged particle beam to capture an image of the sample, characterized in that: Include: a step of obtaining a plurality of sample images captured in a plurality of regions of the sample, and obtaining a characteristic image from each of the plurality of sample images, wherein the characteristic image is an image of a characteristic object included in the sample; and A step of obtaining information of the feature object based on the feature image, The process of obtaining the characteristic image is to repeatedly perform the following process to obtain a plurality of the characteristic images: a step of selecting one mode from a plurality of modes for obtaining the characteristic image based on a ratio of a region of the characteristic object in a field of view in an already obtained sample image; and The step of obtaining the characteristic image in the selected mode, The multiple modes include: a first mode of scanning the sample at a first scanning speed to capture a sample image, and cropping the captured sample image to obtain the characteristic image; as well as The second mode scans the sample at a second scanning speed faster than the first scanning speed to capture a sample image, and scans the region of the characteristic object in the captured sample image at a third scanning speed slower than the second scanning speed to capture the characteristic image.

Images