Charged particle beam apparatus and method for determining lens strength thereof

Abstract

[Task] To enable wide field of view of captured images and improvement of the discriminability of observed objects. [Solution] A charged particle beam device (100) comprises a charged particle beam emitted onto a sample, a deflector that separates signal electrons generated based on the irradiated charged particle beam, a filter that filters the signal electrons, a first lens that parallelizes the direction of travel of the signal electrons separated by the deflector and directs them to the filter, a second lens that focuses the signal electrons that have passed through the filter, a detector that detects the signal electrons that have passed through the second lens, and a computer system (401) that controls the intensity of the first lens and the intensity of the second lens. The computer system (401) changes the intensity of the first lens so that the signal electrons are directed to the filter at a constant angle, and changes the intensity of the second lens so that the signal electrons that have passed through the filter are focused to the detector.

Description

Technology Field

[0001] The present disclosure relates to technology such as a charged particle beam device. Background Technology

[0002] A charged particle beam device is known to have an energy filter for energy filtering of charged particles emitted from a sample, a first deflection element for deflecting charged particles emitted from a sample away from the optical axis of the charged particle beam, and a second deflection element (focusing lens) for further deflecting the charged particles deflected by the first deflection element (see Patent Document 1 below).

[0003] In addition, a charged particle beam device is known that comprises a passage limiting member that limits the passage of a portion of charged particles emitted from a sample, a first lens disposed between the passage limiting member and the sample to control the trajectory of charged particles emitted from the sample, and a second lens disposed between the passage limiting member and a charged particle source to change the focusing conditions of the charged particle beam according to the control conditions of the first lens (see Patent Document 2 below). Prior art literature

[0004] Japanese Patent Publication No. 5899299 and Japanese Patent Publication No. 2017-16755 The problem to be solved

[0005] In the process of manufacturing a semiconductor device, which is an example of a sample, a charged particle beam, such as an electron beam, is irradiated onto the sample by a charged particle beam device, and signal electrons generated from the sample, such as secondary electrons or reflected electrons, are acquired to inspect the surface condition of the sample and measure various defects, including short circuits in wiring.

[0006] An example of a charged particle beam device is a scanning electron microscope. A scanning electron microscope generates a primary beam from an electron source to scan a sample, and creates an image by detecting signal electrons generated by the interaction between the sample and the electrons, thereby performing inspection or measurement of the object to be observed.

[0007] With the recent miniaturization and three-dimensionalization of semiconductor devices, the number and diversity of objects to be observed are increasing, requiring high-speed inspection or measurement. To achieve high-speed inspection or measurement, it is effective to widen the field of view of the image to capture a wider area in a single observation and to improve the discriminability of the objects to be observed.

[0008] The objective of the present disclosure is to provide a technology that enables wide field of view of an image and improved discrimination of an observation target in a charged particle beam device. means of solving the problem

[0009] Representative embodiments of the present disclosure have the configurations shown below. A charged particle beam device of one embodiment comprises a charged particle source that irradiates a charged particle beam toward a sample; a deflector that separates signal electrons generated based on the charged particle beam and the charged particle beam irradiated toward the sample; a filter that filters the signal electrons based on the energy amount of the signal electrons; a first lens that parallelizes the direction of travel of the signal electrons separated by the deflector and directs them to the filter; a second lens that focuses the signal electrons that have passed through the filter; a detector that detects the signal electrons that have passed through the second lens; and a computer system that controls the intensity of the first lens and the intensity of the second lens. The computer system changes the intensity of the first lens so that the signal electrons are directed to the filter at a certain angle, and changes the intensity of the second lens so that the signal electrons that have passed through the filter are focused to the detector.

[0010] A charged particle beam device of one embodiment comprises a charged particle source that irradiates a charged particle beam toward a sample, a deflector that separates signal electrons generated based on the charged particle beam and the charged particle beam irradiated toward the sample, a filter that filters the signal electrons based on the energy amount of the signal electrons, a first lens that parallelizes the direction of travel of the signal electrons separated by the deflector and directs them to the filter, a second lens that focuses the signal electrons that have passed through the filter, a detector that detects the signal electrons that have passed through the second lens, and a computer system that controls the intensity of the first lens and the intensity of the second lens. A method for determining the lens intensity of a charged particle beam device comprises a step in which the computer system changes the intensity of the first lens so that the signal electrons are incident on the filter at a certain angle, and a step in which the computer system changes the intensity of the second lens so that the signal electrons that have passed through the filter are focused to the detector. Effects of the invention

[0011] According to a representative embodiment of the present disclosure, a charged particle beam device is provided that enables wide field of view of an image and improvement of the discriminability of an observation target. Problems, configurations, effects, etc. other than those described above are described in the embodiments for carrying out the invention. Brief explanation of the drawing

[0012] FIG. 1 is a schematic diagram illustrating an example of the configuration of a charged particle beam device of a first embodiment. FIG. 2 is a diagram for schematically explaining the configuration of an imaging unit of a first embodiment. FIG. 3 is a diagram illustrating an example of a case where the detector of the first embodiment is composed of five detectors. FIG. 4 is a drawing illustrating an example in which a part of the detector of the first embodiment is made into an indirect detector. FIG. 5 is a drawing illustrating an example of a case where the detection unit of the first embodiment is of the divided type. FIG. 6 illustrates an example in which the shape of the signal electronic conversion member of the first embodiment is a pipe shape. FIG. 7 is an example of a case where the shape of the signal electronic conversion member of the first embodiment is an induced shape that is axially symmetric with respect to the optical axis of the second optical system. FIG. 8 is an example of a case in which partitions corresponding to each detector are added to the signal electronic conversion member of the first embodiment. FIG. 9 is a schematic diagram illustrating an example of an SEM image with shading occurring according to the first embodiment. FIG. 10 is a schematic diagram illustrating an example of an SEM image with suppressed shading according to a first embodiment. Figure 11 is a diagram illustrating the trajectory of signal electrons during the imaging of the SEM image of Figure 9. Figure 12 is a diagram illustrating the trajectory of signal electrons during the capture of the SEM image of Figure 10. FIG. 13 is a flowchart illustrating an example of a process for determining the intensity of a signal electronic control lens according to a first embodiment. FIG. 14 is a diagram for schematically explaining the configuration of the imaging unit of a charged particle beam device of a second embodiment. FIG. 15 is a schematic diagram illustrating an example of an SEM image showing a top-down image of a second embodiment. FIG. 16 is a schematic diagram illustrating an example of an SEM image showing a top-down image of a second embodiment. Fig. 17 is a schematic diagram illustrating an example of a cross-section of a sample during observation of the SEM image shown in Fig. 15. FIG. 18 is a schematic diagram illustrating an example of a cross-section of a sample during observation of the SEM image shown in FIG. 16. FIG. 19 is a schematic diagram illustrating an example of an SEM image showing a shaded image of a low step difference structure of the second embodiment. FIG. 20 is a schematic diagram illustrating an example of an SEM image showing a shaded image captured by emphasizing the shaded contrast of the second embodiment. FIG. 21 is a schematic diagram illustrating an example of the trajectory of a signal electron during the imaging of FIG. 19. FIG. 22 is a schematic diagram illustrating an example of the trajectory of a signal electron during the imaging of FIG. 20. FIG. 23 is a flowchart illustrating an example of a process for determining the intensity of a signal electronic control lens according to a second embodiment. FIG. 24 is a diagram for schematically explaining the configuration of the imaging unit of a charged particle beam device of a third embodiment. FIG. 25 is a flowchart illustrating an example of a process for determining the intensity of a signal electronic control lens according to a third embodiment. FIG. 26 is a diagram for schematically explaining the configuration of the imaging unit of a charged particle beam device in a modified example of the third embodiment. FIG. 27 is a flowchart showing an example of a process for determining the strength of a signal electronic control lens in a modified example of the third embodiment. FIG. 28 is a diagram for schematically explaining the configuration of the imaging unit of a charged particle beam device of the fourth embodiment. Specific details for implementing the invention

[0013] <Prerequisites for explaining the technology of the present disclosure>

[0014] In inspection or measurement using a scanning electron microscope, it is often required to measure both the top-down image, observed directly above the sample, and the shadow image, which forms shadows in a specific direction. One method to improve the discriminability of the observed object is to optimize the top-down image and the shadow image according to the shape or condition of the object. To utilize this method, the scanning electron microscope needs to control at least one of the emission energy and emission angle of the signal electrons acquired by the detector to match the observation symmetry; for instance, when a sample is significantly charged, it is necessary to form a top-down image that suppresses charge by using only signal electrons with a specific energy, or when detecting defects in the lower layer of the sample, it is necessary to form a shadow image by increasing the ratio of signal electrons in the vertical component of the sample.

[0015] In addition, to widen the field of view of the image captured by a scanning electron microscope, it is necessary to increase the scanning range of the sample by the primary beam. When scanning the sample with the primary beam, the position of signal electron generation is biaxial, and the final arrival position of the signal electron also changes because it is affected by the deflection field caused by scanning. Therefore, shading may occur in which the brightness at the edges of the field of view decreases compared to the center of the field of view as the scanning range increases.

[0016] For example, the technology described in the above patent document 1 discloses, more specifically, a method of selecting the energy of the acquired signal electrons without affecting the primary beam by preventing a decrease in detection efficiency by separating the signal electrons by a deflection element and then focusing the signal electrons at the detector by means of a focusing lens and an energy filter installed between the detector and the signal electrons.

[0017] In addition, for example, the technology described in the above patent document 2 discloses, more specifically, a method of controlling the emission angle of signal electrons incident on the detector by newly installing a control lens between the sample and the detector and focusing or diverging signal electrons.

[0018] According to the technology described in the above patent document 1, it is possible to perform energy discrimination of signal electrons using a focusing lens and an energy filter after separating the signal electrons from the primary beam. However, this method does not take into account that the biaxiality caused by the emission angle of the signal electrons and the biaxiality of the signal electrons generated by scanning the sample are different, so the latter cannot be corrected. Consequently, when the scanning range of the observation target increases due to wide field of view, the entry angle and entry position of the signal electrons generated from the center of the observation target and the signal electrons generated from the end of the observation target, respectively, differ from each other. Therefore, the conditions of the focusing lens cannot be determined uniquely, and in addition to being unable to perform uniform energy filtering within the imaging plane, there is a possibility that shading may occur in the imaging image.

[0019] In addition, according to the technology described in Patent Document 2, it is possible to control the emission angle of signal electrons acquired from the detector. However, this method, like the technology described in Patent Document 1, does not take into account that the biaxiality caused by the emission angle of signal electrons and the biaxiality of signal electrons generated by scanning the sample are different, and therefore, the latter cannot be corrected. Consequently, if the scanning range of the observation target increases due to wide field of view, in addition to the inability to acquire uniform angle components within the imaging plane, there is a possibility that shading may occur in the image.

[0020] As described above, when attempting to control the emission angle or emission energy of signal electrons reaching the detector, it is not possible to obtain a uniform angle component or perform uniform energy filtering within the imaging plane due to the incident direction or position of the signal electrons. As a result, in addition to shading, there may be cases where the selectivity of the signal electron emission energy or emission angle is reduced. However, in the above-mentioned patent documents 1 and 2, no explanation is provided regarding countermeasures against shading or changes in the selectivity of signal electrons caused by sample scanning.

[0021] Below, a charged particle beam device is described for the purpose of achieving the reduction of shading caused by sample scanning and high-resolution energy filtering, or the reduction of shading caused by sample scanning and the angle control of signal electrons.

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same reference numerals are given to identical parts in principle, and repetitive descriptions are omitted. In the drawings, the representation of components may not show their actual location, size, shape, range, etc., in order to facilitate understanding of the invention.

[0023] For explanatory purposes, when describing processing by a program, the program, function, or processing unit is often described as the subject; however, the hardware subject for these is the processor, or a controller, device, computer system, or system composed of such processor. A computer system executes processing according to a program read into memory by the processor, while appropriately utilizing resources such as memory and communication interfaces. Through this, a predetermined function or processing unit is realized. The processor is composed of semiconductor devices, such as a CPU / MPU or GPU. Processing is not limited to software program processing and can also be implemented using dedicated circuits. Dedicated circuits such as FPGAs, ASICs, and CPLDs can be applied.

[0024] The program may be pre-installed as data on the target computer system, or distributed as data from the program source to the target computer system. The program source may be a program distribution server on a communication network, or a non-transient computer-readable storage medium, such as a memory card or a disk. The program may be composed of multiple modules. The computer system may be composed of multiple devices. The computer system may be composed of a client-server system, a cloud computing system, an IoT system, etc. Various data and information may be organized into structures such as tables or lists, but are not limited thereto. Representations such as identification information, identifiers, IDs, names, and numbers are interchangeable.

[0025] [First Embodiment]

[0026] <Configuration of the Imaging Unit of the Charged Particle Beam Device>

[0027] First, the charged particle beam device (100) will be described with reference to FIGS. 1 and FIG. 2. FIG. 1 is a schematic diagram illustrating an example of the configuration of the charged particle beam device (100). Also, in FIG. 1, a detailed illustration of the imaging unit (300) of the charged particle beam device (100) is omitted. FIG. 2 is a diagram for schematically explaining the configuration of the imaging unit (300).

[0028] As illustrated in FIGS. 1 and 2, a charged particle beam device (100) includes an imaging unit (300), a computer system (401), and a stage moving mechanism (110). The imaging unit (300) is, for example, a Scanning Electron Microscope (SEM). The computer system (401) is, for example, a personal computer. The stage moving mechanism (110) moves a stage (11) that loads a sample (10). The computer system (401) is connected to communicate with the imaging unit (300) and the stage moving mechanism (110), respectively. The imaging unit (300) and the stage moving mechanism (110) operate based on the control of the computer system (401). Additionally, the computer system (401) receives a detection signal detected by a detector (15 to 17) included in the imaging unit (300).

[0029] The imaging unit (300) has an electron source (1) (charged particle source), a deflection element (7) (deflection device), an energy filter (14) (filter), a signal electron control lens (12) (first lens), a signal electron control lens (13) (second lens), and a plurality of detectors (15 to 17) (detectors). The electron source (1) irradiates a charged particle beam (201) toward a sample (10). The deflection element (7) separates signal electrons generated based on the charged particle beam (201) and the charged particle beam irradiated toward the sample (10). The energy filter (14) filters the signal electrons based on the amount of energy of the signal electrons. The signal electron control lens (12) parallelizes the direction of travel of the signal electrons separated by the deflection element (7) and directs them to the energy filter (14). The signal electron control lens (13) focuses the signal electrons that have passed through the energy filter (14). Detectors (15 to 17) detect signal electrons that have passed through the signal electron control lens (13). Below, a more detailed configuration of the imaging unit (300) will be explained with reference to FIG. 2.

[0030] The imaging unit (300) is an electron optical system and has a primary optical system (301) and a secondary optical system (302). The primary optical system (301) performs a series of controls until electrons emitted from an electron source (1) reach the sample (10). The secondary optical system (302) controls signal electrons generated by the interaction between the sample (10) and a charged particle beam (201) (hereinafter referred to as the "primary beam (201)") irradiated from the primary optical system (301). A deflection element (7) is disposed at the junction of the primary optical system (301) and the secondary optical system (302) to deflect the signal electrons toward the secondary optical system (302) and guide them toward detectors (15 to 17).

[0031] The central axes (101 and 102) shown by the dashed lines in FIG. 2 are the mechanical central axes of the columns of the primary optical system (301) and the secondary optical system (302), respectively. In FIG. 2, the primary beam (201) is shown as a thick line, the orbit (202) that widens due to the emission angle of the signal electrons generated at the center of the sample (10) is shown as a dashed line, and the signal electrons (203) that are emitted vertically from the sample (10) by scanning the sample are shown as a solid line. In addition, regarding the emission angle of the signal electrons, the one emitted from the sample (10) parallel to the central axis (101) and also toward the electron source (1) is treated as an emission angle of 0 degrees. In addition, signal electrons generated by spreading out from the same location of the sample (10) according to the emission angle are treated as signal electron A (first signal electron), and signal electrons generated from another location of the sample (10) in the direction of an emission angle of 0 degrees by sample scanning are treated as signal electron B (second signal electron).

[0032] In the primary optical system (301), between the electron source (1) and the sample (10), an extraction electrode (2) for extracting electrons from the electron source (1), an acceleration electrode (3) for accelerating the extracted electrons as a primary beam (201), a lens (4) for determining the opening angle of the primary beam (201), an aperture (5), a focusing lens (6) for focusing on the deflection element (7), the deflection element (7), a deflection device (8) for scanning the sample (10), and an objective lens (9) for focusing the primary beam (201) onto the sample (10) are arranged. Additionally, the sample (10) is placed on a stage (11). The stage (11) is operated by a stage movement mechanism (110) in the planar direction and height direction of the stage (11), a direction for adjusting the angle of the stage surface of the stage (11), and a rotation direction for rotating the stage (11).

[0033] In the secondary optical system (302), two signal electronic control lenses and an energy filter (14) are disposed between the deflection element (7) and the detectors (15 to 17). At least two signal electronic control lenses may be provided, and three or more signal electronic control lenses may be provided. In this embodiment, the case in which two signal electronic control lenses, a signal electronic control lens (12) and a signal electronic control lens (13), are provided in the secondary optical system (302) is described.

[0034] In addition, the primary optical system (301) may include, in addition to the configuration shown in FIG. 2, an astigmatism corrector, a multi-stage lens, a detector, and any other optical element acting on the primary beam (201) or the trajectory (202) or signal electron (203).

[0035] Additionally, the imaging unit (300) includes, as detectors in this embodiment, detector (15) (first detector), detector (16) (second detector), and detector (17) (third detector). The detection surfaces of the signal electrons of detector (15), detector (16), and detector (17) are each positioned opposite the filter surface of the energy filter (14). Detector (16) is positioned opposite the central part of the energy filter (14). Detector (15) and detector (17) are each positioned opposite the other end of the energy filter (14) with detector (16) in between.

[0036] Additionally, the detector installed in the secondary optical system (302) is composed of three direct detectors (detectors (15 to 17)) in FIG. 2, but the effect of the technology disclosed in this disclosure is not lost even if the number of detectors is other than that, more specifically, four or more. FIG. 3 is a drawing illustrating an example in which the detector is composed of five detectors (151, 15, 16, 17, 171).

[0037] Additionally, some or all of the detectors may be changed to indirect detectors or split-type detectors. FIG. 4 is a diagram illustrating an example in which some of the detectors are indirect detectors. As shown in FIG. 4, detector (16) is a direct detector, and detectors (15A, 17A) are indirect detectors. The indirect detectors (15A, 17A) indirectly detect reflected electrons that are reflected after a signal electron collides with a signal electron conversion member (28), or tertiary electrons generated from the signal electron conversion member (28). FIG. 5 is a diagram illustrating an example in which the detector is of the split type. As shown in FIG. 5, one detector (16A) is divided into four parts (16A1 to 16A4), and signal electrons are detected in each of the divided parts (16A1 to 16A4).

[0038] In addition, the shape of the signal electronic conversion member (28) is not limited to the plate shape shown in FIG. 4, which has already been described. FIGS. 6 to 8 are drawings illustrating variations of the signal electronic conversion member (28), respectively. FIG. 6 is an example where the shape of the signal electronic conversion member (28) is a pipe-shaped signal electronic conversion member (28A). FIG. 7 is an example where the shape of the signal electronic conversion member (28) is an induced shape signal electronic conversion member (28B) that is axially symmetric with respect to the central axis (102) of the secondary optical system (302). FIG. 8 is an example where a partition (29) corresponding to each detector (15A, 16, 17A) is added. By providing the signal electronic conversion members (28A, 28B) or the partition (29) in this way, the signal discrimination performance of each detector can be improved.

[0039] In addition, the energy filter (14) is a plate-shaped mesh filter in FIG. 1, but it may be a structure in which an equipotential surface is formed at least in a certain angle direction with respect to the orbit of the signal electron B, and for example, it may be an annular energy filter. The certain angle direction is preferably a vertical direction.

[0040] The computer system (401) controls the operation of the imaging unit (300) and the operation of the stage moving mechanism (110). The computer system (401) performs processing such as controlling the intensity of the signal electronic control lens (12) and the intensity of the signal electronic control lens (13), for example. More specifically, the computer system (401) performs processing such as changing the intensity of the signal electronic control lens (12) so that signal electrons are incident on the energy filter (14) at a certain angle (vertical in this embodiment), and changing the intensity of the signal electronic control lens (13) so that signal electrons passing through the energy filter (14) are focused on the detectors (15 to 17). The computer system (401) has, for example, a control unit (402), a signal processing unit (403), an input / output unit (404), and a memory unit (405). In the computer system (401), the communication unit, etc., is omitted.

[0041] The control unit (402) includes, for example, a processor, ROM, RAM, etc. In addition to controlling, for example, the operation of scanning the observation target of the sample (10) in the imaging unit (300) within the imaging range and the operation of the stage moving mechanism (110), the control unit (402) performs a process of determining the intensity of the signal electronic control lenses (12, 13) described later with reference to FIG. 13.

[0042] The signal processing unit (403) generates a detection image, for example, an SEM image, based on the signal electrons output from the detectors (15 to 17). The signal processing unit (403) generates image data of the SEM image by storing the detection signal in a frame memory, etc., in synchronization with the scanning of a scanning deflector, for example, not shown.

[0043] The input / output unit (404) is, for example, an input device such as a keyboard or mouse, and a display device such as a display. The operator inputs various instructions for the charged particle beam device (100) by operating the input device of the input / output unit (404). In addition, the operator recognizes various information displayed on the display device of the input / output unit (404), for example, an SEM image.

[0044] The memory unit (405) is, for example, a Hard Disk Drive (HDD) or a Solid State Drive (SSD). The memory unit (405) also functions as a non-temporary recording medium for storing, for example, a program for realizing a process for determining the intensity of the signal electronic control lens (12, 13).

[0045] <Image Processing of Sample>

[0046] In this embodiment, the primary beam (201) is drawn from the electron source (1) by the extraction electrode (2) and accelerated by the acceleration electrode (3). Afterward, the primary beam (201) is adjusted by the lens (4) for determining the opening angle so that the required area passes through the aperture (5). The primary beam (201) is focused once at the position of the deflection element (7) by the focusing lens (6), and then focused onto the sample (10) by the objective lens (9). At this time, the primary beam (201) is diverted from the central axis (101) of the primary optical system using a diverter (8) for scanning, and scanning of the imaging range of the sample (10) is performed.

[0047] Signal electrons generated from the sample (10) are lifted and separated into a secondary optical system (302) by a deflection element (7). To achieve high-resolution energy filtering, it is necessary to always induce signal electron B at the same angle with respect to the energy filter (14). In this embodiment, signal electron B is controlled to always be perpendicular to the energy filter (14) by the front signal electron control lens (12). After passing through the energy filter (14), signal electron B is controlled to be focused on the detectors (15 to 17) by the rear signal electron control lens (13). Signal electron B is incident on the detector (16), and signal electron A is incident on the detectors (15 to 17). Accordingly, in this embodiment, a top-down image is acquired at the detector (16) closest to the central axis (102) of the secondary optical system, and a shadow image is acquired at the detector (15) and the detector (17).

[0048] <Control of the first signal electronic control lens and energy filter>

[0049] Next, the control of the signal electron control lens (12) and the energy filter (14) will be described. As previously explained, in order to achieve high-resolution energy filtering, it is necessary for the signal electron B to always be incident on the energy filter (14) at the same angle. In this embodiment, high-resolution energy filtering is achieved by making the trajectory of the signal electron B perpendicular to the energy filter (14) by the signal electron control lens (12), but it is not necessary for it to be perpendicular. What is important in this embodiment is that the signal electron B is incident on the energy filter (14) at the same angle. That is, it is sufficient to control the signal electron B so that it is incident on the energy filter (14) at a constant angle.

[0050] <Control of the second signal electronic control lens>

[0051] Next, the control of the signal electron control lens (13) will be described. FIG. 9 is an example of a schematic diagram of an SEM image (V1) in which shading has occurred. FIG. 10 is an example of a schematic diagram of an SEM image (V2) in which shading has been suppressed. In addition, FIG. 11 and FIG. 12 are diagrams illustrating the trajectories of signal electron A when acquiring the SEM images (V1, V2) of FIG. 9 and FIG. 10, respectively. In FIG. 11 and FIG. 12, only the secondary optical system (302) is shown, and the trajectory (204) of the signal electron A originating from the center of the sample (10) is indicated by a dotted line, and the trajectory (205) of the signal electron A originating from a point away from the center of the sample is indicated by a dashed line.

[0052] As illustrated in FIGS. 9 and 10, a low step structure (M1) is formed in the sample (10) as an object of observation. The low step structure (M1) is a structure in which a cross-shaped concave portion is formed when viewed from the top surface.

[0053] In order to suppress the shading shown in FIG. 9, it is necessary to reduce the difference in signal amount acquired by the detector (16) during scanning of the central and end portions of the field of view. However, as shown in FIG. 11, the amount of signal electron A incident on the detector (16) differs between the central and end portions of the field of view, resulting in a difference in signal amount. To reduce this difference in signal amount, as shown in FIG. 12, for example, signal electron A having a certain angle from the sample (10) must be incident on the detector (16), so that the final arrival position of signal electron A does not change according to the sample scanning, but changes only according to the exit angle from the sample (10), and thus the intensity of the signal electron control lens (13) must be appropriately set.

[0054] The intensity of the signal electronic control lens (12) and the signal electronic control lens (13) may be determined by reading a calculated value from a calculation table that has been calculated in advance according to each optical condition, or it may be determined according to the type (material, structure) of the sample (10) and the type or size of the object to be observed.

[0055] Processing to determine the intensity of lenses for signal electronic control

[0056] Next, a process for determining the intensity of the signal electronic control lenses (12, 13) will be described. FIG. 13 is a flowchart showing an example of a process for determining the intensity of the signal electronic control lenses (12, 13). This process is realized, for example, by the control unit (402) reading and executing a program stored in the memory unit (405).

[0057] As optical conditions are set by the operator, the control unit (402) obtains the setting of optical conditions in step ST101. Next, in step ST102, the control unit (402) reads a calculation table that has been calculated in advance so that the signal electron takes a desired trajectory.

[0058] Next, the control unit (402), in step ST103, determines whether to perform additional adjustment of the intensity of the signal electronic control lens (signal electronic control lens (12) and signal electronic control lens (13)) based on the optical condition setting and calculation table. For example, the operator recognizes the SEM image displayed on the display device of the input / output unit (404). The operator inputs whether adjustment is necessary by operating the input device of the input / output unit (404). Based on this input instruction, the control unit (402) performs the determination in step ST103.

[0059] If it is determined that no further adjustment of the signal electronic control lens is required (ST103: "No"), the control unit (402) determines the intensity of the signal electronic control lens (12) and the signal electronic control lens (13) in step ST104.

[0060] If it is determined that additional adjustment of the signal electronic control lens is required (ST103: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (12) (the first signal electronic control lens) in step ST105. Next, the control unit (402) determines in step ST106 whether there is a luminance deviation in the image acquired during the operation of the energy filter (14), that is, the SEM image captured by the imaging unit (300). If it is determined that there is a luminance deviation (ST106: "Yes"), the process returns to step ST105, and the control unit (402) changes the intensity of the signal electronic control lens (12) again.

[0061] For example, the operator recognizes the SEM image displayed on the display device of the input / output unit (404). The operator recognizes whether there is a luminance deviation in the SEM image and inputs the recognition result through the input device of the input / output unit (404). The control unit (402) performs the determination of step ST106 based on the input instruction. The change in intensity is adjusted, for example, based on the input operation of the input device of the operator's input / output unit (404), so that no unevenness in the luminance change of the acquired image occurs during the operation of the energy filter (14). By doing so, the computer system (401) can obtain an image with no luminance deviation.

[0062] Additionally, if it is determined that there is no luminance deviation (ST106: "No"), the control unit (402) changes the intensity of the signal electronic control lens (13) (second signal electronic control lens) in step ST107. Next, the control unit (402) determines whether the focal position is at the detector position in step ST108. More specifically, the control unit (402) determines whether the focal position of the signal electron passing through the signal electronic control lens (13) corresponds to the detection surface of the detectors (15 to 17). If it is determined that the focal position is not at the detector position (ST108: "No"), the process returns to step ST107, and the control unit (402) changes the intensity of the signal electronic control lens (13) again.

[0063] For example, the operator recognizes the SEM image displayed on the display device of the input / output unit (404). The operator recognizes whether the imaging range is clearly captured in the SEM image and inputs the recognition result through the input device of the input / output unit (404). The control unit (402) performs the determination of step ST108 based on the input instruction. The intensity is changed so that the acquired image becomes clear, for example, based on the input operation of the input device of the input / output unit (404) of the operator. By doing so, the charged particle beam device (100) can obtain a clear SEM image by aligning the detector position with the focus of the signal electron.

[0064] Next, the control unit (402) determines the intensity of the signal electronic control lens (12) and the signal electronic control lens (13) in step ST109. That is, the intensity of the signal electronic control lens (12) determined by the processing of steps ST105 and ST106 above, and the intensity of the signal electronic control lens (13) determined by the processing of steps ST107 and ST108 are determined as the final intensity of the signal electronic control lens (12) and the signal electronic control lens (13).

[0065] Inspection using a charged particle beam device

[0066] Next, a means for inspecting a sample (10) using a charged particle beam device (100) is described. When an operator inspects a desired sample (10), first, the operator sets the optical conditions of the imaging unit (300) using the input / output unit (404). By setting the optical conditions, the voltage of the extraction electrode (2) and the voltage of the acceleration electrode (3) are changed based on a calculation table, and accordingly, the lens of the primary optical system (301) is appropriately adjusted. In addition, the means for measuring the sample (10), etc. using a charged particle beam device is also the same.

[0067] After that, a deflection element (7) is set so that signal electrons generated vertically from the center of the sample (10) are incident on the center of the detector (16).

[0068] Next, signal electrons emitted vertically from the sample (10) by the signal electronic control lens (12) and the signal electronic control lens (13) become parallel at the position of the energy filter (14). The parallel signal electrons are focused at the position of the detector. While maintaining this state, the intensity of the energy filter (14) is changed according to the sample (10) (or object to be observed), and the charged particle beam device (100) performs imaging until a desired image is obtained.

[0069] As described above, the charged particle beam device (100) can achieve high-resolution energy filtering while suppressing shading caused by sample scanning when imaging a sample (10). That is, the charged particle beam device (100) can achieve both the reduction of shading caused by sample scanning and high-resolution energy filtering.

[0070] Accordingly, the charged particle beam device (100) can enable wide field of view and improved discrimination of the observation target by selectively detecting the angle or energy of the signal electron while suppressing shading. As a result, the charged particle beam device (100) can also realize high speed of inspection and measurement.

[0071] [Second Embodiment]

[0072] <Configuration of the Imaging Unit of the Charged Particle Beam Device>

[0073] First, the imaging unit (310) of the charged particle beam device (100) will be described with reference to FIG. 14. FIG. 14 is a diagram for schematically explaining the configuration of the imaging unit (310) of the charged particle beam device (100). Also, the overall configuration of the charged particle beam device (100) is the same as that shown in FIG. 1. That is, in the second embodiment, the imaging unit (310) shown in FIG. 14 is provided in the charged particle beam device (100) instead of the imaging unit (300) shown in FIG. 2, which has already been described.

[0074] As shown in FIG. 14, the primary optical system (311) of the imaging unit (310) has the same configuration as the primary optical system (301) shown in FIG. 2. The secondary optical system (312) controls signal electrons generated by the interaction between the primary beam (201) and the sample (10).

[0075] In the secondary optical system (312), at least three signal electronic control lenses are arranged between the deflection element (7) and the detectors (15 to 17). In this embodiment, a signal electronic control lens (18), a signal electronic control lens (19), and a signal electronic control lens (20) are arranged. Compared to the case of FIG. 2, the imaging unit (310) is not provided with an energy filter (14).

[0076] In this embodiment, after the signal electrons are incident on the secondary optical system (312), the signal electrons B are focused onto the signal electron control lens (19) by the signal electron control lens (18). Additionally, the signal electron control lens (19) operates to act only on the signal electrons A to control the angle of the signal electrons reaching the detectors (15 to 17). Furthermore, the signal electron control lens (20) operates to focus the signal electrons B, which are widened by the signal electron control lens (19), onto the detector (16). For example, if the intensity of the signal electron control lens (19) is set to a weaker intensity than the state shown in FIG. 14, signal electrons B having a larger emission angle are incident on the detector (16). In this embodiment, when changing the emission angle of the signal electrons B acquired by the detectors (15 to 17), the computer system (401) can do so by controlling only the signal electron control lens (19).

[0077] Next, an example is described in which the object of observation is a hole (M2) formed on a sample (10). FIGS. 15 and 16 are schematic diagrams illustrating an example of SEM images (V3, V4) showing a top-down view of the hole (M2) and the bottom of the hole (M2B), and also an example of a case where signal electron A is focused by a signal electron control lens (19) and acquired by a detector (16). FIGS. 17 and 18 are schematic diagrams illustrating an example of a cross-section of the sample (10) during observation of the SEM images (V3, V4) shown in FIGS. 15 and 16, and also an example of a case where signal electron A is diverged by a signal electron control lens (19) and only the vertical component is acquired by a detector (16).

[0078] Consider the case where all signal electrons (601 to 603) generated from the sample (10) are detected, as illustrated in FIG. 17. In this case, signal electrons (602) with a large emission angle generated from the hole (M2) at the bottom of the hole (M2B) are blocked by the side wall of the hole (M2) and are not radiated upward. Because of this, only signal electrons (603) with a smaller emission angle than signal electrons (602) can be detected by the detector (16). Consequently, the amount of signal detected from the hole (M2) to be observed is reduced compared to the amount of signal electrons (601) generated from the surroundings of the hole (M2). For this reason, the computer system (401) controls the intensity of the signal electron control lens (19) and, as shown in FIG. 18, limits the angle of the signal electron detected by the detector to an angle below a certain level, thereby making it possible for the charged particle beam device (100) to improve the discriminability of the hole (M2).

[0079] Next, as another example, a case in which a low step structure is captured as an observation target will be described. The low step structure (M1) is a structure in which a cross-shaped concave portion is formed when viewed from the top surface, similar to the case in FIG. 9. FIG. 19 is a schematic diagram illustrating an example of an SEM image (V5) showing a shaded image of the low step structure (M1). FIG. 20 is a schematic diagram illustrating an example of an SEM image (V6) showing a shaded image captured by emphasizing the contrast of the shade using the technology of the present embodiment. FIG. 21 and FIG. 22 are schematic diagrams illustrating examples of the trajectory (207) of signal electron A and the trajectory (206) of signal electron B generated from the center of the sample (10) during the imaging of FIG. 19 and FIG. 20, respectively. Additionally, FIGS. 21 and 22 illustrate the trajectory of a signal electron in a secondary optical system (312) in a second embodiment, and the trajectory (207) of signal electron A originating from the center of the sample (10) is shown as a dotted line, and the trajectory (206) of signal electron B is shown as a solid line.

[0080] When capturing a low-step structure (M1), as shown in FIG. 19, the computer system (401) may not be able to detect the low-step structure (M1) to be observed because the contrast of the shading of the low-step structure (M1) is weak. To emphasize the contrast of the shading, the shading image can be formed using only signal electrons having a larger emission angle. Accordingly, the computer system (401) controls the intensity of the signal electron control lens (19) so that only a portion of the orbit (207) of signal electron A is incident on the detector (15) and the detector (17). By doing so, the computer system (401) can emphasize the contrast of the shading, making it possible to acquire the SEM image (V6) shown in FIG. 20.

[0081] As explained above, by controlling the angle of the signal electrons acquired by the detectors (15 to 17) by inputting the input device of the input / output unit (404) according to the state of the SEM image of the object to be observed, the charged particle beam device (100) can generate an image desired by the operator.

[0082] Additionally, the computer system (401) may determine the intensity of the signal electronic control lenses (18 to 20) from a calculated value calculated in advance according to each optical condition, or may determine it according to the type and material of the sample (10) and the shape of the object to be observed.

[0083] Processing to determine the intensity of lenses for signal electronic control

[0084] Next, a process for determining the intensity of the signal electronic control lenses (18 to 20) will be described. FIG. 23 is a flowchart showing an example of a process for determining the intensity of the signal electronic control lenses (18 to 20). This process is realized, for example, by the control unit (402) reading and executing a program stored in the memory unit (405).

[0085] When optical conditions are set by the operator, the control unit (402) obtains the setting of optical conditions in step ST201, reads a calculation table that has been calculated in advance so that the signal electron takes a desired trajectory in step ST202, and determines whether to perform additional adjustment of intensity in step ST203, respectively, which is the same as steps ST101 to ST103 described above. If it is determined that additional adjustment of the signal electron control lens is not necessary (ST203: "No"), the control unit (402) determines the intensity of the signal electron control lens (18 to 20) (third to fifth signal electron control lens) in step ST204.

[0086] If it is determined that additional adjustment of the signal electronic control lens is required (ST203: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (18) (third signal electronic control lens) in step ST205. Next, the control unit (402) determines whether there is a luminance deviation in the SEM image captured by the imaging unit (310) in step ST206. If it is determined that there is a luminance deviation (ST206: "Yes"), the process returns to step ST205, and the control unit (402) changes the intensity of the signal electronic control lens (18) again. These processes are the same as the processes of steps ST105 and ST106 described above.

[0087] If it is determined that there is no luminance deviation (ST206: "No"), the control unit (402) changes the intensity of the signal electronic control lens (20) (the fifth signal electronic control lens) in step ST207. Next, the control unit (402) determines whether the focus position is at the detector position in step ST208. If it is determined that the focus position is not at the detector position (ST208: "No"), the process returns to step ST207, and the control unit (402) changes the intensity of the signal electronic control lens (20) again. These processes are the same as the processes of steps ST107 and ST108 described earlier.

[0088] If it is determined that the focal position is at the detector position (ST208: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (19) (the fourth signal electronic control lens) in step ST209. Next, the control unit (402) determines whether the desired image has been obtained in step ST210. If it is determined that the desired image has not been obtained (ST210: "No"), the process returns to step ST209, and the control unit (402) changes the intensity of the signal electronic control lens (19).

[0089] For example, the operator recognizes the SEM image displayed on the display device of the input / output unit (404). The operator determines whether adjustment is necessary by operating the input device of the input / output unit (404). Based on this input instruction, the control unit (402) makes a determination in step ST210. The change in intensity is changed, for example, based on the operator's operation of the input / output unit (404). By doing so, the computer system (401) can obtain the image desired by the user.

[0090] When it is determined that the desired image has been obtained (ST210: "Yes"), the control unit (402) determines the intensity of the signal electronic control lenses (18 to 20) in step ST211. The intensity determined in this way becomes the final intensity of the signal electronic control lenses (18 to 20).

[0091] As described above, the charged particle beam device (100) can select the angle of signal electrons acquired from detectors (15 to 17) while suppressing shading caused by sample scanning. That is, the charged particle beam device (100) can achieve both the reduction of shading caused by sample scanning and the control of the angle of signal electrons.

[0092] [Third Embodiment]

[0093] The third embodiment is an embodiment that combines the first and second embodiments. It will be described in detail below.

[0094] <Configuration of the Imaging Unit of the Charged Particle Beam Device>

[0095] First, the imaging unit (320) of the charged particle beam device (100) will be described with reference to FIG. 24. FIG. 24 is a diagram for schematically explaining the configuration of the imaging unit (320) of the charged particle beam device (100). In addition, the overall configuration of the charged particle beam device (100) is the same as that shown in FIG. 1. That is, in the third embodiment, the imaging unit (320) shown in FIG. 24 is provided in the charged particle beam device (100) instead of the imaging unit (300) shown in FIG. 2, which has already been described.

[0096] As shown in FIG. 24, the primary optical system (321) of the imaging unit (320) has the same configuration as the primary optical system (301) shown in FIG. 2. The secondary optical system (322) controls signal electrons generated by the interaction between the primary beam (201) and the sample (10).

[0097] In the secondary optical system (322), at least four signal electronic control lenses are arranged between the deflection element (7) and the detectors (15 to 17). In this embodiment, four signal electronic control lenses (21 to 24) (6th to 9th signal electronic control lenses: 1st to 4th lenses) are arranged. Additionally, in the secondary optical system (322), an energy filter (25) is arranged between the signal electronic control lens (21) and the signal electronic control lens (22).

[0098] The detection surfaces of the signal electrons of the detectors (15), detector (16), and detector (17) are each positioned opposite the filter surface of the energy filter (25). The detector (16) is positioned opposite the central part of the energy filter (25). The detectors (15) and detector (17) are each positioned opposite the other end of the energy filter (25) with the detector (16) in between. Signal electron B is detected by the detector (16), and signal electron A is detected by the detectors (15) to (17), just as in the previously described embodiment.

[0099] The signal electronic control lens (21) is a lens that parallelizes the signal electron B. The signal electronic control lens (22) is a lens that focuses the signal electron B. The signal electronic control lens (23) is a lens that controls the angle of the signal electron reaching the detector. The signal electronic control lens (24) is a lens that focuses the signal electron B.

[0100] After the signal electron enters the secondary optical system (322), the signal electron B proceeds so that it is always perpendicular to the energy filter (25) by controlling the signal electron control lens (21) at the front end with the computer system (401). After passing through the energy filter (25), the signal electron B is focused at the center position of the signal electron control lens (23) by controlling the signal electron control lens (22) at the rear end with the computer system (401), and is also focused again at the detector (16) by controlling the signal electron control lens (24) at the rear end with the computer system (401).

[0101] While maintaining this state, the computer system (401) changes the intensity of the signal electronic control lens (23) and the intensity of the energy filter (25), so that the charged particle beam device (100) can control the emission angle and emission energy of signal electron A acquired from the detectors (15 to 17) while focusing signal electron B at the detector location.

[0102] Processing to determine the intensity of lenses for signal electronic control

[0103] Next, a process for determining the intensity of the signal electronic control lenses (21 to 24) will be described. FIG. 25 is a flowchart illustrating an example of a process for determining the intensity of the signal electronic control lenses (21 to 24). This process is realized, for example, by the control unit (402) reading and executing a program stored in the memory unit (405).

[0104] When optical conditions are set by the operator, the control unit (402) obtains the setting of optical conditions in step ST301, reads a calculation table that has been calculated in advance so that the signal electron takes a desired trajectory in step ST302, and determines whether to perform additional adjustment of intensity in step ST303, respectively, which is the same as steps ST101 to ST103 described above. If it is determined that additional adjustment of the signal electron control lens is not necessary (ST303: "No"), the control unit (402) determines the intensity of the signal electron control lens (21 to 24) (6th to 9th signal electron control lens) in step ST304.

[0105] If it is determined that additional adjustment of the signal electronic control lens is required (ST303: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (21) (the sixth signal electronic control lens) in step ST305. Next, the control unit (402) determines whether there is a luminance deviation in the SEM image captured by the imaging unit (320) in step ST306. If it is determined that there is a luminance deviation (ST306: "Yes"), the process returns to step ST305, and the control unit (402) changes the intensity of the signal electronic control lens (21) again. These processes are the same as the processes of steps ST105 and ST106 described above.

[0106] If it is determined that there is no luminance deviation (ST306: "No"), the control unit (402) changes the intensity of the signal electronic control lens (22) (the seventh signal electronic control lens) in step ST307. Next, the control unit (402) determines whether a luminance deviation occurs during the operation of the energy filter (25) in step ST308. If it is determined that a luminance deviation occurs (ST308: "No"), the process returns to step ST307, and the control unit (402) changes the intensity of the signal electronic control lens (22) again.

[0107] For example, the operator recognizes the SEM image displayed on the display device of the input / output unit (404). The operator operates the energy filter (25) to recognize whether a brightness deviation occurs in the SEM image during the operation of the energy filter (25), and inputs the recognition result through the input device of the input / output unit (404). The control unit (402) performs the determination of step ST308 based on the input instruction. The change in intensity is, for example, based on the input operation of the operator's input / output unit (404), so that the change in brightness of the SEM image is reduced. By doing so, the charged particle beam device (100) can prevent a tendency of non-uniformity in the change in brightness of the SEM image from occurring during the operation of the energy filter (25).

[0108] If it is determined that there is no luminance deviation (ST308: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (24) (the ninth signal electronic control lens) in step ST309. Next, the control unit (402) determines whether the focus position is at the detection position in step ST310. If it is determined that the focus position is not at the detector position (ST310: "No"), the process returns to step ST309, and the control unit (402) changes the intensity of the signal electronic control lens (24) again. These processes are the same as the processes of steps ST107 and ST108 described earlier.

[0109] If it is determined that the focal position is at the detection position (ST310: "Yes"), the control unit (402) changes the intensity of the signal electronic control lens (23) (the eighth signal electronic control lens) in step ST311. Next, the control unit (402) determines whether the desired image has been obtained in step ST312. If it is determined that the desired image has not been obtained (ST312: "No"), the process returns to step ST311, and the control unit (402) changes the intensity of the signal electronic control lens (23). These processes are the same as the processes of steps ST209 and ST210 described earlier.

[0110] When it is determined that the desired image has been obtained (ST312: "Yes"), the control unit (402) determines the intensity of the signal electronic control lenses (21 to 24) in step ST313. This determined intensity becomes the final intensity of the signal electronic control lenses (21 to 24).

[0111] By determining the intensity of the signal electron control lenses (21 to 24) in this manner, the charged particle beam device (100) can selectively detect the angle and energy of the signal electrons while suppressing shading caused by sample scanning and enabling the selection of the angle of the signal electrons acquired by the detectors (15 to 17). Even with this configuration, the charged particle beam device (100) can enable wide field of view and improved discrimination of the observation target.

[0112] <Variation Example>

[0113] Next, a modified example of the third embodiment will be described. In this modified example, the secondary optical system (322) shown in FIG. 24 is modified into the secondary optical system (332) shown in FIG. 26.

[0114] <Configuration of the Imaging Unit of the Charged Particle Beam Device>

[0115] First, the imaging unit (330) of the charged particle beam device will be described with reference to FIG. 26. FIG. 26 is a diagram for schematically explaining the configuration of the imaging unit (330) of the charged particle beam device (100). In addition, the overall configuration of the charged particle beam device (100) is the same as that shown in FIG. 1.

[0116] As shown in FIG. 26, the secondary optical system (332) is similar to the secondary optical system (322) shown in FIG. 24 in that it has signal electronic control lenses (21 to 24), but the position where the energy filter (25) is placed is different. In the secondary optical system (332), the energy filter (25) is placed between the signal electronic control lens (23) and the signal electronic control lens (24).

[0117] The signal electronic control lens (21) focuses the signal electron B. The signal electronic control lens (22) controls the angle of the signal electron reaching the detector. The signal electronic control lens (23) parallelizes the signal electron B. The signal electronic control lens (24) focuses the signal electron B at the detector location.

[0118] Processing to determine the intensity of lenses for signal electronic control

[0119] Next, a process for determining the intensity of the signal electronic control lenses (21 to 24) will be described. FIG. 27 is a flowchart illustrating an example of a process for determining the intensity of the signal electronic control lenses (21 to 24). This process is realized, for example, by the control unit (402) reading and executing a program stored in the memory unit (405).

[0120] The processing of steps ST401 to ST404 is identical to the processing of steps ST301 to ST304 that has already been described. For this reason, the description of the processing of steps ST401 to ST404 is omitted. In addition, the adjustment of the intensity of the signal electronic control lenses (21 to 24) is performed by the operator operating the input / output unit (404), just as in the third embodiment.

[0121] The control unit (402) changes the intensity of the signal electronic control lens (21) (the sixth signal electronic control lens) to suppress the brightness deviation of the SEM image during imaging by processing steps ST405 and ST406. By doing so, the computer system (401) can suppress the brightness deviation of the SEM image during imaging.

[0122] Next, the control unit (402), by processing steps ST407 and ST408, changes the intensity of the signal electronic control lens (23) (the 8th signal electronic control lens) so that no tendency of brightness deviation occurs in the captured SEM image when the energy filter (25) is operated. By doing so, the computer system (401) can prevent brightness deviation from occurring when the energy filter (25) is operated.

[0123] Next, the control unit (402) changes the intensity of the signal electronic control lens (24) (the ninth signal electronic control lens) so that the detector position and the focus of the signal electronic are aligned by processing steps ST409 and ST410. By doing so, the computer system (401) can align the detector position and the focus of the signal electronic.

[0124] Next, the control unit (402) changes the intensity of the signal electronic control lens (22) (the seventh signal electronic control lens) so that a desired image is obtained by processing steps ST411, ST412, and ST413. These processing steps are the same as those previously described, ST311, ST312, and ST313.

[0125] Even when using an imaging unit (330) that includes a secondary optical system (332) as described above, the charged particle beam device (100), like the third embodiment, can selectively detect the angle and energy of signal electrons while suppressing shading caused by sample scanning and enabling the selection of the angle of signal electrons acquired from detectors (15 to 17). Even with such a configuration, the charged particle beam device (100) can enable wide field of view and improved discrimination of the observation target.

[0126] [Fourth Embodiment]

[0127] In the fourth embodiment, a deflector and an aperture for selecting the field of view are added to the secondary optical system (322) of the imaging unit (320) of the charged particle beam device (100) of the third embodiment, thereby further modifying the configuration of the detector.

[0128] <Configuration of the Imaging Unit of the Charged Particle Beam Device>

[0129] First, the imaging unit (340) of the charged particle beam device (100) will be described with reference to FIG. 28. FIG. 28 is a diagram for schematically explaining the configuration of the imaging unit (340) of the charged particle beam device (100). In addition, the overall configuration of the charged particle beam device (100) is the same as that shown in FIG. 1. Below, the secondary optical system (342) of the imaging unit (340) will be described in detail.

[0130] As illustrated in FIG. 28, the configuration of the three detectors is different from that of FIG. 24. Specifically, the detection surface of the detector (16) is positioned opposite the filter surface of the energy filter (25). The detection surfaces of the detector (15A) and the detector (17A) are positioned at a different angle (90 degrees: vertical in this embodiment) from the filter surface of the energy filter (25), and each detection surface is positioned opposite to the other. Signal electron B is detected by the detector (16), and signal electron A is detected by the detectors (15A, 16, 17A). That is, the configuration of the three detectors is the same as the configuration of the detectors (15A, 16, 17A) described using FIG. 4.

[0131] Additionally, a deflector (26) and an aperture (27) for field selection are added between the signal electronic control lens (24) and the detectors (15A, 16, 17A). The computer system (401) is capable of controlling the deflection of the deflector (26) and controlling the aperture of the aperture (27) based on the operation of the operator's input / output unit (404). The computer system (401) can detect an energy spectrum by operating the aperture (27) and the deflector (26) for field selection, using the signal electronic B detected by the detector (16).

[0132] Next, a method for acquiring an energy spectrum is described. The signal electronic control lenses (21 to 24) operate in the same manner as described in the third embodiment. In this embodiment, the computer system (401) controls the intensity of the signal electronic control lenses (24) based on the operation of the operator to prevent the signal electrons B from being focused at the detector location. Then, the computer system (401) controls the deflection of the deflector (26) for field selection to divert the signal electrons B, and the operator selects the signal electrons at the location where the energy spectrum is to be acquired using the aperture (27).

[0133] While maintaining this state, the computer system (401) changes the intensity of the energy filter (25) to measure the signal amount of signal electrons incident on the detector (16). Then, the computer system (401) can obtain an energy spectrum by matching the intensity of the energy filter (25) with the signal amount detected by the detector (16).

[0134] Additionally, the computer system (401) can change the region when acquiring the energy spectrum by controlling the magnification of signal electron B with a signal electron control lens (24). By doing so, the computer system (401) can acquire the energy spectrum of the biased region.

[0135] Additionally, the computer system (401) can display the acquired energy spectrum on the input / output unit (404). By doing so, the operator can see the energy spectrum of a desired area within the observation area.

[0136] As described above, the charged particle beam device (100) can acquire the energy spectrum of the observation area of ​​the sample (10) after imaging with wide field of view, by having the operator specify a specific location or specific area of ​​the object to be observed.

[0137] Although embodiments of the present disclosure have been described in detail above, they are not limited to the aforementioned embodiments and can be modified in various ways without departing from the gist of the content. Each embodiment may include, with the exception of essential components, components may be added, deleted, or substituted. Unless specifically limited, each component may be singular or plural. A combination of each embodiment or a modified example is also possible. Each of the aforementioned components, functions, processing units, etc., may be realized in part or in whole in hardware, for example, by designing an integrated circuit, or in software by a processor interpreting and executing a program. Data and information such as programs, tables, and files that realize each function may be stored in a recording device such as memory, a hard disk, or an SSD, or in a recording medium such as an IC card, an SD card, or a DVD. Explanation of the symbols

[0138] 1: Electron source, 2: Extraction electrode, 3: Acceleration electrode, 4: Lens, 5: Aperture, 6: Focusing lens, 7: Deflection element, 8: Deflection device for primary use, 9: Objective lens, 10: Sample, 11: Stage, 12, 13: Lenses for signal electronic control, 14, 25: Energy filter, 15 to 17: Detector, 18 to 24: Lenses for signal electronic control, 26: Deflection device for field of view selection, 27: Aperture, 28, 28A, 28B: Signal electronic conversion element, 29: Partition plate, 100: Charged particle beam device, 101: Central axis of the primary optical system, 102: Central axis of the secondary optical system, 201: Primary beam, 202: Trajectory widened by the emission angle of signal electrons generated from the center of the sample, 203: From the sample by sample scanning Biaxially emitted signal electrons, 204: Orbit widened by the emission angle of signal electrons originating from the sample center, 205: Magnification by the emission angle of signal electrons originating from a point away from the sample center, 206: Orbit of signal electrons biaxially emitted from the sample by sample scanning, 207: Orbit widened by the emission angle of signal electrons originating from the sample center, 300, 310, 320, 330, 340: Imaging unit, 301: Primary optical system, 302, 312, 322, 332, 342: Secondary optical system, 401: Computer system, V1 to V6: SEM images

Claims

Claim 1 A charged particle beam device comprising: a charged particle source that irradiates a charged particle beam toward a sample; a deflector that separates signal electrons generated based on the charged particle beam and the charged particle beam irradiated toward the sample; a filter that filters the signal electrons based on the amount of energy of the signal electrons; a first lens that parallelizes the direction of travel of the signal electrons separated by the deflector and directs them to the filter; a second lens that focuses the signal electrons that have passed through the filter; a detector that detects the signal electrons that have passed through the second lens; and a computer system that controls the intensity of the first lens and the intensity of the second lens, wherein the computer system changes the intensity of the first lens so that the signal electrons are directed to the filter at a certain angle, and changes the intensity of the second lens so that the signal electrons that have passed through the filter are focused to the detector. Claim 2 A charged particle beam device according to claim 1, wherein the constant angle is an angle in which the direction of propagation of the signal electron is perpendicular to the filter. Claim 3 A charged particle beam device according to claim 1, wherein the detector comprises a first detector, a second detector, and a third detector, and the detection surfaces of the signal electrons of the first detector, the second detector, and the third detector are each positioned opposite to the filter surface of the filter, the second detector is positioned opposite to the center of the filter, and the first detector and the third detector are each positioned opposite to the other end of the filter with the second detector in between, and the signal electrons include a first signal electron that is generated by spreading out according to the emission angle from the charged particle beam irradiated at the same location of the sample, and a second signal electron that is generated in the direction of the emission angle from another location of the sample by scanning the sample with the charged particle beam, wherein the second signal electron is detected by the second detector, and the first signal electron is detected by the first detector, the second detector, and the third detector. Claim 4 In paragraph 3, the charged particle beam device further comprises a third lens for focusing the first signal electron that has passed through the second lens to the first detector, and a fourth lens for focusing the second signal electron that has passed through the second lens to the second detector and the third detector, and the computer system further controls the intensity of the third lens and the intensity of the fourth lens. Claim 5 In claim 1, the detector comprises a first detector, a second detector, and a third detector, wherein the detection surface of the second detector is positioned opposite to the filter surface of the filter, and the detection surfaces of the first detector and the third detector are positioned at an angle different from the filter surface and their respective detection surfaces are positioned opposite to each other, and the signal electrons comprise a first signal electron generated by spreading out according to the emission angle from the charged particle beam irradiated at the same location of the sample, and a second signal electron generated in the direction of the emission angle from another location of the sample by scanning the sample with the charged particle beam, wherein the second signal electrons are detected by the second detector, and the first signal electrons are detected by the first detector, the second detector, and the third detector, and the charged particle beam device comprises a third lens that focuses the first signal electrons passing through the second lens to the first detector, and the second signal electrons passing through the second lens to the second detector and the third detector. A charged particle beam device further comprising a fourth lens for focusing, an aperture for narrowing the signal electrons detected by the first detector, and a field selection deflector for selecting a field of view, wherein the computer system also controls the intensity of the third lens and the intensity of the fourth lens, and operates the aperture and the field selection deflector to detect an energy spectrum by the first signal electrons detected by the second detector. Claim 6 In claim 1, the computer system is a charged particle beam device having a display unit that displays an image generated based on the signal electrons detected by the detector. Claim 7 In claim 6, the computer system is a charged particle beam device having an input section for changing the intensity of the first lens and the second lens. Claim 8 In claim 7, the computer system changes at least one of the intensities of the first lens and the second lens based on instructions input from the input unit according to an image displayed on the display unit, a charged particle beam device. Claim 9 A method for determining lens intensity of a charged particle beam device comprising: a charged particle source that irradiates a charged particle beam toward a sample; a deflector that separates signal electrons generated based on the charged particle beam and the charged particle beam irradiated toward the sample; a filter that filters the signal electrons based on the amount of energy of the signal electrons; a first lens that parallelizes the direction of travel of the signal electrons separated by the deflector and directs them to the filter; a second lens that focuses the signal electrons that have passed through the filter; a detector that detects the signal electrons that have passed through the second lens; and a computer system that controls the intensity of the first lens and the intensity of the second lens. The method for determining lens intensity comprises a step in which the computer system changes the intensity of the first lens so that the signal electrons are directed to the filter at a certain angle, and a step in which the computer system changes the intensity of the second lens so that the signal electrons that have passed through the filter are focused to the detector.

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