Photoelectron microscope and defect detection method

Abstract

The present invention provides a photoelectron microscope that can easily be switched from the visual field of a low-magnification image to the visual field of a high-magnification image for observing a target ROI at a high magnification. When shifting from a first process for taking a first photoelectron image at a first magnification to a second process for taking a second photoelectron image at a second magnification higher than the first magnification, photoelectrons are deflected by a deflector 17 and the strength of at least one of a plurality of first lenses 16a is changed such that, in a state in which a sample image has been formed at the aperture of a diaphragm 18, the sample image in the second process is an image in which a partial area included in the sample image in the first process is enlarged.

Description

Photoelectron microscope and defect detection method

[0001] The present invention relates to a photoelectron microscope and a defect detection method using the same.

[0002] A photoelectron emission microscope (PEEM) is a device that forms an image using photoelectrons generated by irradiating the surface of a sample with excitation light such as ultraviolet light or X-rays, and can obtain a photoelectron image with contrast resulting from the surface structure of the sample.

[0003] The electron spectrometer disclosed in Patent Document 1 includes an input lens that introduces electrons into an analyzer, and the input lens includes, in order from the sample side, a main magnification control lens L1, an auxiliary magnification control lens L2, an imaging lens L3, and a deceleration lens LR, and a field-limiting aperture is disposed between the auxiliary magnification control lens L2 and the imaging lens L3 to separate the inside of the input lens. The field-limiting aperture is provided to limit the area that captures photoelectrons generated on the sample surface, and this aperture limits the analysis area on the sample.

[0004] US Pat. No. 5,699,499 discloses a PEEM equipped with an aberration corrector that corrects chromatic and spherical aberrations in a photoelectron image.

[0005] JP 2003-187738 A Japanese Patent No. 7381515 A

[0006] Optical inspection systems that use light and scanning electron microscope (SEM) inspection systems that use electron beams are widely used as inspection systems for patterns formed on the surface of semiconductor wafers. Optical inspection systems and SEM inspection systems differ in the size of structures that can be observed on a sample (semiconductor wafer). While optical inspection systems can quickly inspect pattern shapes over a large inspection area, the smaller the defects, the more difficult they are to detect. In contrast, SEM inspection systems are effective at detecting minute defects, but their observation field of view is narrow, and the larger the inspection area, the lower the throughput of pattern shape inspection.

[0007] The inventors have studied an inspection device (PEEM inspection device) that detects pattern defects from photoelectron images taken by PEEM, as an inspection device that can achieve both the throughput of an optical inspection device and the defect detection resolution of an SEM inspection device.

[0008] While PEEM is expected to improve throughput by capturing images of a wide field of view all at once, in order to review the region of interest (ROI) extracted during the inspection in detail, it is necessary to capture an enlarged photoelectron image of the extracted ROI. In this case, if the photoelectrons expand too much inside the column and collide with the column wall, problems such as unexpected electron scattering and contamination of the inner wall may occur.

[0009] Although Patent Document 1 discloses an input lens having a similar structure as an electron optical system, it does not disclose or suggest a method for switching a wide field of view to one suitable for observing an extracted ROI, or a device capable of switching.

[0010] A photoelectron microscope as one embodiment of the present invention comprises an excitation light source that irradiates a sample with excitation light, a camera that captures a photoelectron image due to photoelectrons emitted from the sample irradiated with the excitation light, an imaging electron optical system that forms the photoelectron image on the camera, and a control unit. The imaging electron optical system comprises an aperture having an aperture that allows a portion of the photoelectrons to pass through, a deflector that is arranged on the sample side of the aperture, and a lens group including a plurality of first lenses that are arranged on the sample side of the aperture and a plurality of second lenses that are arranged on the camera side of the aperture. When transitioning from a first step of capturing a first photoelectron image at a first magnification to a second step of capturing a second photoelectron image at a second magnification that is higher than the first magnification, the control unit deflects the photoelectrons using the deflector while the sample image is formed at the aperture opening, and changes the strength of at least one of the plurality of first lenses so that the sample image in the second step is an image in which a portion of the area included in the sample image in the first step is enlarged.

[0011] The present invention provides a photoelectron microscope that can easily switch from a low-magnification image field of view to a high-magnification image field of view for observing a target ROI at high magnification. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0012] 1 is a configuration example of a photoelectron microscope. FIG. 2 is a flowchart of an inspection and review process. FIG. 3 is an example of a sample image formed at an aperture of an aperture. FIG. 4 is an example of a sample image formed at an aperture of an aperture. FIG. 5 is a diagram for explaining a method of enlarging a sample image. FIG. 6 is a diagram showing how excitation light is irradiated onto a sample. FIG. 7 is a diagram for explaining a method of adjusting the magnification of an imaging electron optical system. FIG. 8 is a configuration example of a photoelectron microscope equipped with an aberration corrector. FIG. 9 is a configuration example of a photoelectron microscope equipped with an energy analyzer. FIG. 10 is a configuration example of a photoelectron microscope equipped with an energy analyzer. FIG. 11 is a diagram showing the trajectory of photoelectrons that form a normal sample image. FIG. 12 is a diagram showing the trajectory of photoelectrons in an angular distribution acquisition mode. FIG. 13 is a flowchart of defect detection using a photoelectron microscope. FIG. 14 is an example of a recipe setting screen.

[0013] FIG. 1 shows a PEEM (photoelectron image) system that obtains an image of photoelectrons generated by irradiating the surface of a sample with excitation light such as laser light or X-rays. The imaging unit 10 primarily comprises a stage 13 on which a sample 14 is placed, an excitation light source 11 that irradiates the sample 14 with excitation light 12, a camera 19 that captures the photoelectron image, and an imaging electron optical system 15 that focuses the photoelectron image on the camera 19. The imaging electron optical system 15 includes a lens group 16, an aperture 18 with an aperture that passes a portion of the photoelectrons emitted from the sample surface, and a deflector 17. The lens group 16 is arranged along the optical axis of the imaging electron optical system 15 and focuses the photoelectron image on the camera 19 at a desired magnification. The aperture 18 is located midway within the lens group 16. The lens of the lens group 16 located closer to the sample 14 than the aperture 18 is sometimes referred to as the sample-side lens 16a, and the lens of the lens group 16 located closer to the camera 19 than the aperture 18 is sometimes referred to as the camera-side lens 16b. The deflector 17 is disposed closer to the sample 14 than the aperture 18 and controls the amount of deflection of photoelectrons traveling from the sample 14 toward the camera 19 .

[0014] The imaging unit 10 is connected to a control unit 20. The control unit 20 controls the imaging unit 10 in response to instructions from a user input via a GUI (Graphical User Interface) device 22, and also performs image processing of the photoelectron image captured by the camera 19. The control unit 20 includes a storage unit 21, which stores control parameters for the imaging unit 10 and the photoelectron image.

[0015] In the PEEM of this embodiment, it is possible to switch the field of view of the sample to be inspected and to carry out the inspection process and review process consecutively. A flowchart of the inspection and review process is shown in FIG.

[0016] First, an inspection image is acquired (S01). The inspection image is an image with a relatively low magnification. As will be described later, in this embodiment, the imaging electron optical system 15 is adjusted so that the specimen image is formed at the aperture of the diaphragm 18. Fig. 3A shows an example of the specimen image formed at the aperture of the diaphragm 18 in step S01. The specimen image located within the aperture 32 of the diaphragm 18 is enlarged and projected onto the camera 19 and acquired as the inspection image. In this example, a specimen image including a 3 × 3 pattern 33 to be inspected is shown.

[0017] Next, an ROI is extracted (S02). For example, design data and photoelectron image data of the pattern to-be-inspected 33 are registered in advance in a dictionary, and image processing such as template matching is performed to extract the pattern to-be-inspected 33 determined to be abnormal as the ROI. As a result, it is assumed that the pattern to-be-inspected 33R (see FIG. 3A ) is extracted as the ROI.

[0018] Next, the ROI is moved to the center of the field of view (S03). The position of the center coordinates of the ROI (pattern to-be-inspected 33R) relative to the field of view center 31 is calculated from the inspection image, and the specimen image is moved by the deflector 17 (image shift) so that the ROI center coordinates are positioned at the field of view center 31. Fig. 3B shows the specimen image formed at the opening of the diaphragm 18 at this stage.

[0019] Next, the magnification of the photoelectron image is increased, and a review image is acquired (S04). Specifically, the sample image formed at the aperture 32 of the diaphragm 18 is enlarged more than the sample image acquired in step S01 so that the dimensions of the ROI do not exceed the size of the aperture 32. Figure 3C shows an example of the sample image formed at the aperture of the diaphragm 18 at this stage.

[0020] The magnification of the specimen image at the aperture of the aperture 18 can be achieved by controlling the intensity of the specimen-side lens 16a. FIG. 4 shows how an image of a pattern 40 on the specimen 14 is formed at the aperture of the aperture 18 when the imaging electron-optical system 15 has a first specimen-side lens 16a-1 and a second specimen-side lens 16a-2. Assume that specimen image 41 is the specimen image at the aperture of the aperture 18 when the inspection image is acquired. By changing the intensity of the specimen-side lenses 16a-1 and 16a-2, a specimen image 42 of the pattern 40, which is larger than specimen image 41, can be obtained. Note that, while an example of magnifying the specimen image by changing the intensity of two specimen-side lenses 16a is shown here, the present invention is not limited to this. The specimen image can also be magnified by changing the intensity of at least one of the multiple specimen-side lenses 16a.

[0021] 5 shows how the excitation light 12 is irradiated onto the sample 14. The photoelectron emission range 51 indicated by the dashed circle is the range in which photoelectrons (indicated by the upward arrow) are emitted when the excitation light 12 is irradiated onto the sample 14, and this range is basically fixed in the inspection and review process shown in FIG. 2. The field of view 52 indicated by the solid circle is the range in which the emitted photoelectrons reach the camera 19. The field of view 52 is included in the photoelectron emission range 51, and a desired photoelectron image is acquired by changing the size of the field of view 52 and the position of the field of view 52 within the photoelectron emission range 51 in the imaging electron optical system 15.

[0022] A method for adjusting the magnification of the imaging electron optical system 15 will be described using Figure 6. Figure 6 schematically shows how images are magnified by lenses on the upstream and downstream sides of the aperture 18 when acquiring low-magnification and high-magnification images. In this embodiment, in the imaging electron optical system 15, the specimen-side lens 16a forms an image of the specimen 14 at the opening of the aperture 18, and the camera-side lens 16b projects the specimen image formed at the opening of the aperture 18 onto the camera 19. Therefore, regardless of the magnification of the photoelectron image captured by the camera 19, the magnification of the image on the camera side relative to the aperture 18 does not change.

[0023] Whether the photoelectron image is a low-magnification image or a high-magnification image is determined by the magnification of the specimen image formed at the opening of the diaphragm 18. Photoelectron images of different magnifications can be obtained by adjusting the size of the specimen image formed at the opening of the diaphragm 18 by the specimen-side lens 16a with the specimen-side lens 16a. Furthermore, to change the position of the field of view, the position where the photoelectrons pass through the opening 32 is adjusted with the deflector 17.

[0024] As described above, according to the optical system adjustment method of this embodiment, when changing the magnification of the photoelectron image, it is not necessary to change the strength of the camera-side lens 16b. If the strength of the camera-side lens 16b were also adjusted when changing the magnification of the photoelectron image, the magnification ratio of the image between the aperture 18 and the camera 19 would be greater than the magnification ratio of the image between the sample 14 and the aperture 18. This could result in photoelectrons colliding with the inner wall of the column during the magnification adjustment and field of view adjustment, resulting in secondary electrons being mixed into the photoelectron image, or gas being generated from the inner wall of the column, causing contamination. In contrast, by adjusting the magnification and field of view using a lens and a deflector located closer to the sample than the aperture 18, it is possible to obtain a desired photoelectron image without causing such problems, and the transition from the inspection process to the review process can be carried out without causing any problems.

[0025] Here, when acquiring a review image in step S04 (see FIG. 2), the magnification may not be simply increased, but the imaging mode may be switched in order to classify defects for the ROI. Examples of imaging modes that can be applied when acquiring a review image will be described below.

[0026] [High-resolution mode] The high-resolution mode can be obtained by correcting the aberration of the imaging electron optical system 15 using an aberration corrector. For example, the structure of an aberration corrector suitable for PEEM is disclosed in Japanese Patent No. 7381515 (Patent Document 2) by the same applicant. An imaging unit 10 equipped with an aberration corrector (excitation light source 11 is omitted) is shown in Figure 7.

[0027] The optical axis 109, which is the center of the trajectory of photoelectrons in the imaging electron optical system, is perpendicular to the sample mounting surface of the stage 13. Therefore, the imaging electron optical system and camera 19 can be housed in an upright column, making it suitable for use in semiconductor manufacturing lines. The imaging electron optical system will be explained by dividing it into three sections, A to C.

[0028] In section A, a sample image is formed at the opening of the aperture 18 by the sample-side lens 16a. In Fig. 7, the on-axis trajectory before incidence on the mirror aberration corrector 106 is shown as on-axis trajectory 110a, and the off-axis trajectory before incidence on the mirror aberration corrector 106 is shown as off-axis trajectory 110b. The lens 103 is an auxiliary lens, and serves to align the off-axis trajectory 110b parallel to the optical axis 109. The photoelectron image is expanded by the sample-side lens 16a and the auxiliary lens 103 from the distance between the on-axis trajectory 110a and the off-axis trajectory 110b in the sample 14 to the distance between the on-axis trajectory 110a and the off-axis trajectory 110b in the magnetic field sector 104a (indicated by the arrow).

[0029] In section B, the chromatic aberration and spherical aberration of the photoelectron image are corrected. A mirror aberration corrector 106 is used to correct the chromatic aberration and spherical aberration of the photoelectron image. The mirror aberration corrector 106 is composed of multiple electrodes, and a voltage applied to the final stage reflects the trajectory near the electrodes. Spherical aberration and chromatic aberration can be corrected by controlling the voltage applied to the electrodes. A known configuration can be used for the mirror aberration corrector 106. The mirror aberration corrector 106 is arranged so as to be perpendicular to the optical axis 109. Therefore, in section B, the magnetic field sectors 104a to 104c are used to shift the trajectory of the photoelectrons away from the optical axis 109, causing them to enter the mirror aberration corrector 106, and then the trajectory of the photoelectrons that have exited the mirror aberration corrector 106 is controlled so as to return them to the optical axis 109. In Figure 7, the on-axis trajectory after exiting the mirror aberration corrector 106 is shown as on-axis trajectory 110c, and the off-axis trajectory after exiting the mirror aberration corrector 106 is shown as off-axis trajectory 110d. The magnetic field sector 104a is arranged so that its center is at the intersection of the on-axis trajectory 110a and the optical axis 109. Similarly, the magnetic field sector 104c is arranged so that its center is at the intersection of the on-axis trajectory 110c and the optical axis 109. In section B, a photoelectron image (indicated by an arrow in the magnetic field sector 104c) with corrected chromatic aberration and spherical aberration is obtained. The magnification of the photoelectron image does not change (1x) between the entrance (magnetic field sector 104a) and exit (magnetic field sector 104c) of section B. A doublet lens 105 is provided between the magnetic field sectors 104 to cancel out deflection aberrations occurring in the upstream magnetic field sector 104.

[0030] In section C, the aberration-corrected photoelectron image (specimen image) is enlarged and projected onto the imaging surface of the camera 19 by the camera-side lens 16b.

[0031] Although not shown in FIG. 7 , a lens group may be arranged along the optical axis 109 between the magnetic field sectors 104a and 104c to enable the aberration corrector to be turned on and off. In the aberration correction OFF mode, no current flows through the magnetic field sectors 104a-c, so that the on-axis trajectory 110a and the off-axis trajectory 110b proceed straight without being deflected by the magnetic field sector 104. The lens group projects the central plane of the magnetic field sector 104a onto the central plane of the magnetic field sector 104c at 1x magnification. By projecting at 1x magnification, it is possible to maintain the same magnification of the imaging electron optical system regardless of whether the magnetic field sectors are on or off (aberration correction ON mode / aberration correction OFF mode). In this case, a higher-resolution image of the ROI can be acquired by using the aberration correction OFF mode when acquiring a low-magnification photoelectron image (during inspection) and the aberration correction ON mode when acquiring a high-magnification photoelectron image (during review).

[0032] [Analyzer Analysis Mode] In the analyzer analysis mode, a photoelectron image of a desired energy band is obtained by providing an energy analyzer in the imaging electron optical system 15. Fig. 8A shows an example of the configuration of the imaging unit 10. When the energy analyzer 61 is turned on, only photoelectrons of the desired energy band pass through the slit 62, making it possible to acquire a photoelectron image of a specific energy band.

[0033] 8B shows an example of the configuration of the imaging unit 10 when an electrostatic hemispherical analyzer is used as the energy analyzer 61. Photoelectrons that have passed through the aperture 18 are introduced into the energy analyzer 61 via the input lens 63. The photoelectrons pass through the energy analyzer 61 on a trajectory that depends on their energy, and only photoelectrons in a desired energy band pass through the slit 62. The photoelectrons that have passed through the slit 62 are projected onto the camera 19 via the output lens 64 and enlarged by the camera-side lens 16b.

[0034] It should be noted that by changing the imaging mode, it is possible to obtain a spectrum instead of a real image.

[0035] [Angular distribution acquisition mode] In the angular distribution acquisition mode, photoelectrons with a uniform emission angle θ are imaged at the position of the aperture 18. For comparison, Fig. 9A shows the trajectories of photoelectrons when the specimen-side lens 16a forms a normal specimen image at the position of the aperture 18. Photoelectrons emitted from points 71a, 71b, and 71c on the specimen 14 are imaged at points 72a, 72b, and 72c on the aperture 18, regardless of their emission angles.

[0036] Fig. 9B shows the trajectories of photoelectrons in the angular distribution acquisition mode. Photoelectrons with different emission angles are emitted from points 71a, 71b, and 71c on the sample 14. Fig. 9B shows trajectories 73aL, aC, and aR of photoelectrons with different emission angles from point 71a, trajectories 73bL, bC, and bR of photoelectrons with different emission angles from point 71b, and trajectories 73cL, cC, and cR of photoelectrons with different emission angles from point 71c. Here, the emission angles of the photoelectrons taking the trajectories 73aL, 73bL, and 73cL are θ Ｌ (θ Ｌ <90°), the emission angle of photoelectrons taking orbits 73aC, 73bC, and 73cC is θ Ｃ (θ Ｃ = 90°), the emission angles of the photoelectrons taking the orbits 73aR, 73bR, and 73cR are θ Ｒ (θ Ｒ In the angular distribution acquisition mode, photoelectrons with the same emission angle are imaged at the same position on the aperture 18 (points 74L, C, R in this example) regardless of their emission position.

[0037] In the angular distribution acquisition mode, it is possible to obtain information about the surface structure of the sample 14. For example, if the photoelectron intensity at point 74R is smaller than the photoelectron intensities at points 74L and 74C, the emission angle θ Ｒ It can be assumed that there is a structure that blocks the photoelectrons from reaching the camera 19.

[0038] FIG. 10 is a flowchart of defect detection using PEEM in this embodiment. A series of processes, from ROI extraction using low-magnification images to review and defect classification using high-magnification images, can be performed. In recipe setting (S11), the inspection area and inspection conditions are set, and review conditions are also set. FIG. 11 shows an example of a recipe setting screen. The recipe setting screen 80 shown in FIG. 11 displays an inspection area setting screen 81 and a review condition setting screen 84. The inspection area setting screen 81 displays a wafer map 82 and a die map 83, allowing the user to specify the die on the wafer to be inspected and the chip on that die. The mode selection section 85 of the review condition setting screen 84 allows the user to select the imaging mode used to acquire high-magnification images for review. Selectable modes include the high-resolution mode, analyzer analysis mode, and angular distribution acquisition mode described above. Review images may be acquired using multiple imaging modes. The review condition setting screen 84 also displays a condition setting screen corresponding to the selected imaging mode. The recipe set on the recipe setting screen 80 is stored in the memory unit 21.

[0039] In the inspection (S12) and review (S13) steps, the inspection and review process shown in Fig. 2 is performed. In the acquisition of a review image (S04), an image of the sample (review image) is captured in the imaging mode set in the recipe setting (S11). Based on one or more review images thus acquired, defect classification (S14) is performed.

[0040] The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to add, delete, or replace part of the configuration of the embodiment with other configurations.

[0041] 10: imaging unit, 11: excitation light source, 12: excitation light, 13: stage, 14: specimen, 15: imaging electron optical system, 16: lens group, 16a: specimen-side lens, 16b: camera-side lens, 17: deflector, 18: aperture, 19: camera, 20: control unit, 21: memory unit, 22: GUI device, 31: field of view center, 32: aperture, 33: inspection target pattern, 40: pattern, 41, 42: specimen image, 51: photoelectron emission range, 52: field of view, 61: energy analyzer, 62: slit , 63: input lens, 64: output lens, 71, 72, 74: points, 73: trajectory, 80: recipe setting screen, 81: inspection area setting screen, 82: wafer map, 83: die map, 84: review condition setting screen, 85: mode selection unit, 103: auxiliary lens, 104: magnetic field sector, 105: doublet lens, 106: mirror aberration corrector, 109: optical axis, 110a: on-axis trajectory, 110b: off-axis trajectory, 110c: on-axis trajectory, 110d: off-axis trajectory.

Claims

1. A photoelectron microscope comprising: an excitation light source that irradiates a sample with excitation light; a camera that captures a photoelectron image formed by photoelectrons emitted from the sample irradiated with the excitation light; an imaging electron optical system that forms the photoelectron image on the camera; and a control unit, wherein the imaging electron optical system comprises an aperture having an aperture that allows some of the photoelectrons to pass, a deflector that is arranged on the sample side of the aperture, and a lens group including a plurality of first lenses that are arranged on the sample side of the aperture and a plurality of second lenses that are arranged on the camera side of the aperture, wherein when transitioning from a first step of capturing a first photoelectron image at a first magnification to a second step of capturing a second photoelectron image at a second magnification that is higher than the first magnification, the control unit deflects the photoelectrons using the deflector and changes the strength of at least one of the plurality of first lenses so that the sample image in the second step is an enlarged image of a portion of the area included in the sample image in the first step, while the sample image is formed at the aperture opening.

2. A photoelectron microscope according to claim 1, wherein the control unit does not change the strength of the plurality of second lenses to change the magnification of the photoelectron image from the first magnification to the second magnification when transitioning from the first step to the second step.

3. A photoelectron microscope according to claim 1, wherein the control unit performs image processing on the first photoelectron image using data registered in a dictionary in advance, and extracts the partial region.

4. A photoelectron microscope according to claim 3, wherein the control unit registers design data or photoelectron image data of a pattern to be inspected formed on the sample in a dictionary in advance, and performs template matching on the first photoelectron image using the design data or the photoelectron image data to extract the partial region.

5. A photoelectron microscope according to claim 1, wherein the control unit captures the second photoelectron image in the second step in an imaging mode selected from high resolution mode, analyzer analysis mode, and angular distribution acquisition mode.

6. A photoelectron microscope according to claim 5, wherein the control unit, in the second step, captures the second photoelectron image in one or more imaging modes selected from the high resolution mode, analyzer analysis mode and angular distribution acquisition mode, and performs defect classification for the region of the sample corresponding to the partial region based on the one or more second photoelectron images.

7. A defect detection method using a photoelectron microscope, wherein the photoelectron microscope comprises an excitation light source that irradiates a sample with excitation light, a camera that captures a photoelectron image formed by photoelectrons emitted from the sample irradiated with the excitation light, an imaging electron optical system that forms the photoelectron image on the camera, and a control unit, wherein the imaging electron optical system comprises an aperture having an aperture that passes a portion of the photoelectrons, a deflector that is arranged on the sample side of the aperture, and a lens group including a plurality of first lenses that are arranged on the sample side of the aperture and a plurality of second lenses that are arranged on the camera side of the aperture, A defect detection method in which, when transitioning from a first step of taking a first photoelectron image at a first magnification to a second step of taking a second photoelectron image at a second magnification higher than the first magnification, the control unit deflects the photoelectrons using the deflector while forming a sample image at the aperture of the diaphragm, so that the sample image in the second step is an enlarged image of a portion of the area included in the sample image in the first step, and changes the strength of at least one of the plurality of first lenses.

8. A defect detection method according to claim 7, wherein the control unit does not change the strength of the plurality of second lenses in order to change the magnification of the photoelectron image from the first magnification to the second magnification when transitioning from the first process to the second process.

9. A defect detection method according to claim 7, wherein the control unit performs image processing on the first photoelectron image using data registered in a dictionary in advance, and extracts the partial region.

10. A defect detection method as set forth in claim 9, wherein the control unit has registered design data or photoelectron image data of a pattern to be inspected formed on the sample in a dictionary in advance, and performs template matching on the first photoelectron image using the design data or the photoelectron image data to extract the partial area.

11. A defect detection method according to claim 7, wherein the control unit captures the second photoelectron image in the second step in an imaging mode selected from high resolution mode, analyzer analysis mode, and angular distribution acquisition mode.

12. A defect detection method as set forth in claim 11, wherein in the second step, the control unit captures the second photoelectron image in one or more imaging modes selected from the high resolution mode, analyzer analysis mode, and angular distribution acquisition mode, and performs defect classification for the region of the sample corresponding to the partial region based on one or more of the second photoelectron images.

Images