Charged particle beam apparatus and method for determining the lens intensity thereof

Abstract

To enable wider field-of-view imaging and improved discriminability of observed objects. [Solution] The charged particle beam apparatus 100 includes a deflector that separates the charged particle beam emitted from a sample from 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 causes them to enter 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 enter 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 on the detector.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to technologies such as charged particle beam apparatuses.

BACKGROUND ART

[0002] There is known a charged particle beam apparatus that includes an energy filter for performing energy filtering on charged particles emitted from a sample, the charged particle beam apparatus including a first deflection element that deflects the charged particles emitted from the sample so as to separate the charged particles from the optical axis of the charged particle beam, and a second deflection element (focusing lens) that further deflects the charged particles deflected by the first deflection element (see Patent Document 1 below).

[0003] There is also known a charged particle beam apparatus that includes a passage restricting member for restricting passage of part of charged particles emitted from a sample, a first lens disposed between the passage restricting member and the sample for controlling trajectories of the charged particles emitted from the sample, and a second lens disposed between the passage restricting member and a charged particle source for changing a focusing condition of the charged particle beam in accordance with a control condition of the first lens (see Patent Document 2 below).

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In a process of manufacturing a semiconductor device that 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 apparatus, and signal electrons generated from the sample such as secondary electrons or backscattered electrons are acquired, whereby inspection of the surface state of the sample and measurement of various defects including short circuits in wiring are performed.

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

[0007] With the recent miniaturization and three-dimensionalization of semiconductor devices, the number and diversity of objects to be observed are increasing, and there is a demand for faster inspection or measurement. To speed up inspection or measurement, it is effective to widen the field of view of the captured image by capturing a wider area in a single observation, and to improve the discriminative ability of the objects to be observed.

[0008] The purpose of this disclosure is to provide a technology that enables wider field-of-view imaging and improved discriminability of observed objects in charged particle beam apparatus. [Means for solving the problem]

[0009] A typical embodiment of this disclosure has the following configuration. The charged particle beam apparatus of one embodiment includes a charged particle source that irradiates a sample with a charged particle beam, a deflector that separates the charged particle beam from signal electrons generated based on the charged particle beam irradiated onto 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 causes them to enter 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 enter 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 on the detector.

[0010] A charged particle beam apparatus according to one embodiment includes a charged particle source that irradiates a sample with a charged particle beam, a deflector that separates the charged particle beam from signal electrons generated based on the charged particle beam irradiated onto 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 causes them to enter 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 the charged particle beam apparatus includes the steps of: the computer system changing the intensity of the first lens so that the signal electrons enter the filter at a constant angle; and the computer system changing the intensity of the second lens so that the signal electrons that have passed through the filter are focused on the detector. [Effects of the Invention]

[0011] According to a representative embodiment of this disclosure, a charged particle beam apparatus can be provided that enables wider field-of-view imaging and improved discriminability of observed objects. Other issues, configurations, and effects will be shown in the embodiments for carrying out the invention. [Brief explanation of the drawing]

[0012] [Figure 1] This figure schematically shows an example of the configuration of a charged particle beam apparatus according to the first embodiment. [Figure 2] This is a diagram illustrating the configuration of the imaging unit in the first embodiment. [Figure 3] This figure shows an example where the detector of the first embodiment is composed of five detectors. [Figure 4] This figure shows an example where a part of the detector in the first embodiment is used as an indirect detector. [Figure 5] This figure shows an example where the detection unit of the first embodiment is of a split type. [Figure 6] This shows an example in which the shape of the signal electron conversion member of the first embodiment is a pipe shape. [Figure 7] This is an example in which the shape of the signal electron conversion member of the first embodiment is a mortar shape that is axisymmetric with respect to the optical axis of the secondary optical system. [Figure 8] This is an example in which partitions corresponding to each detector are added to the signal electron conversion member of the first embodiment. [Figure 9] This is a schematic diagram showing an example of an SEM image in which shading of the first embodiment has occurred. [Figure 10] This is a schematic diagram showing an example of an SEM image in which the shading of the first embodiment is suppressed. [Figure 11] This is a diagram showing trajectories of signal electrons when capturing the SEM image of Fig. 9. [Figure 12] This is a diagram showing trajectories of signal electrons when capturing the SEM image of Fig. 10. [Figure 13] This is a flowchart showing an example of processing for determining the intensity of the signal electron control lens of the first embodiment. [Figure 14] This is a diagram for schematically explaining the configuration of the imaging unit of the charged particle beam apparatus of the second embodiment. [Figure 15] This is a schematic diagram showing an example of an SEM image showing a top-down image of the second embodiment. [Figure 16] This is a schematic diagram showing an example of an SEM image showing a top-down image of the second embodiment. [Figure 17] This is a schematic diagram showing an example of the cross section of the sample when observing the SEM image shown in Fig. 15. [Figure 18] This is a schematic diagram showing an example of the cross section of the sample when observing the SEM image shown in Fig. 16. [Figure 19] This is a schematic diagram showing an example of an SEM image showing a shadow image of a low step structure of the second embodiment. [Figure 20] This is a schematic diagram showing an example of an SEM image showing a shadow image captured with enhanced shadow contrast of the second embodiment. [Figure 21]Figure 19 is a schematic diagram showing an example of the trajectory of signal electrons during imaging. [Figure 22] Figure 20 is a schematic diagram showing an example of the trajectory of signal electrons during imaging. [Figure 23] This flowchart shows an example of the process for determining the intensity of the signal electronic control lens in the second embodiment. [Figure 24] This diagram schematically illustrates the configuration of the imaging unit of the charged particle beam apparatus according to the third embodiment. [Figure 25] This flowchart shows an example of the process for determining the intensity of the signal electronic control lens in the third embodiment. [Figure 26] This figure schematically illustrates the configuration of the imaging unit of a charged particle beam apparatus in a modified example of the third embodiment. [Figure 27] This flowchart shows an example of the process for determining the intensity of the signal electronic control lens in a modified example of the third embodiment. [Figure 28] This figure schematically illustrates the configuration of the imaging unit of the charged particle beam apparatus according to the fourth embodiment. [Modes for carrying out the invention]

[0013] <Assumptions for explaining the technology in this disclosure> In inspection or measurement using a scanning electron microscope, it is often required to measure both a top-down image, which is an observation of the sample from directly above, and a shaded image, which is a shadow formed in a specific direction. One method to improve the discriminative ability of the observed object is to optimize the top-down image and the shaded image according to the shape and condition of the observed object. To use 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 according to the observed object. For example, in the case of a sample with significant charge, it is necessary to form a top-down image with suppressed charge using only signal electrons with a specific energy, or, when detecting defects in the lower layer of the sample, it is necessary to increase the proportion of signal electrons in the vertical component of the sample to form a shaded image.

[0014] Furthermore, to widen the field of view of scanning electron microscope images, it is necessary to increase the scanning range of the sample by the primary beam. When a sample is scanned with the primary beam, the source position of the signal electrons shifts, and the final destination position of the signal electrons also changes due to the influence of the deflection field caused by scanning. Therefore, as the scanning range increases, shading may occur, where the brightness at the edges of the field of view decreases compared to the center of the field of view.

[0015] For example, the technology described in Patent Document 1 above discloses, in more detail, a method in which signal electrons are separated by a deflection element, and then focused by a detector using a focusing lens and energy filter installed between the element and the detector, thereby preventing a decrease in detection efficiency and selecting the energy of the signal electrons to be acquired without affecting the primary beam.

[0016] Furthermore, for example, the technology described in Patent Document 2 above discloses a method for controlling the emission angle of signal electrons incident on the detector by newly installing a control lens between the sample and the detector to focus or diverge the signal electrons.

[0017] According to the technology described in Patent Document 1 above, it is possible to separate the signal electrons from the primary beam and then perform energy discrimination of the signal electrons using a focusing lens and an energy filter. However, this method does not take into account that the deaxial shift due to the emission angle of the signal electrons and the deaxial shift of the signal electrons generated to scan the sample are different, and the latter cannot be corrected. Therefore, as the scanning range of the object being observed increases due to widening the field of view, the entry angle and entry position into the energy filter of the signal electrons generated from the center of the object and the signal electrons generated from the edges of the object will differ. Consequently, the conditions of the focusing lens cannot be uniquely determined, and in addition to not being able to perform uniform energy filtering within the imaging plane, shading may occur in the captured image.

[0018] Furthermore, according to the technology described in Patent Document 2, it is possible to control the emission angle of signal electrons acquired by the detector. However, this method, like the technology described in Patent Document 1, does not take into account that the deaxial shift due to the emission angle of signal electrons and the deaxial shift of signal electrons caused by scanning the sample are different, and therefore correction for the latter cannot be performed. Consequently, when the scanning range of the object to be observed increases due to widening the field of view, it becomes impossible to acquire a uniform angular component within the imaging plane, and shading may occur in the captured image.

[0019] As described above, when attempting to control the emission angle and emission energy of signal electrons reaching the detector, it becomes impossible to acquire a uniform angular component or uniform energy filtering within the imaging plane depending on the incident direction and position of the signal electrons. As a result, shading occurs, and the selectivity of the emission energy and emission angle of the signal electrons may decrease. However, the above-mentioned Patent Documents 1 and 2 do not explain any countermeasures for shading or changes in the selectivity of signal electrons caused by sample scanning.

[0020] The following describes a charged particle beam apparatus aimed at achieving both reduction of shading caused by sample scanning and high-resolution energy filtering, or at achieving both reduction of shading caused by sample scanning and angle control of signal electrons.

[0021] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same parts are generally denoted by the same reference numerals, and repeated descriptions are omitted. In the drawings, the representation of components may not show their actual location, size, shape, extent, etc., in order to facilitate understanding of the invention.

[0022] In explanations, when describing program-based processing, the focus may sometimes be on the program, functions, or processing units. However, the main hardware component is the processor, or a controller, device, computer system, or other system composed of such a processor. A computer system, using resources such as memory and communication interfaces as appropriate, executes processing according to the program read into memory. This realizes the specified functions and processing units. A processor is composed of semiconductor devices such as a CPU / MPU or GPU. Processing is not limited to software program processing; it can also be implemented using dedicated circuits. FPGAs, ASICs, CPLDs, etc., can be used as dedicated circuits.

[0023] The program may be pre-installed as data on the target computer system, or it may be 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 disk. The program may consist of multiple modules. The computer system may consist of multiple devices. The computer system may consist of a client-server system, a cloud computing system, an IoT system, etc. Various types of data and information may be, but are not limited to, structures such as tables and lists. Representations such as identification information, identifiers, IDs, names, and numbers are interchangeable.

[0024] [First Embodiment] <Configuration of the imaging unit of a charged particle beam apparatus> First, the charged particle beam apparatus 100 will be described with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing an example of the configuration of the charged particle beam apparatus 100. Note that in Figure 1, the detailed illustration of the imaging unit 300 of the charged particle beam apparatus 100 is omitted. Figure 2 is a diagram for schematic explanation of the configuration of the imaging unit 300.

[0025] As shown in Figures 1 and 2, the charged particle beam apparatus 100 includes an imaging unit 300, a computer system 401, and a stage movement 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 movement mechanism 110 moves the stage 11 on which the sample 10 is placed. The computer system 401 is communicated with the imaging unit 300 and the stage movement mechanism 110, respectively. The imaging unit 300 and the stage movement mechanism 110 operate based on the control of the computer system 401. The computer system 401 also receives detection signals detected by detectors 15-17 included in the imaging unit 300.

[0026] The imaging unit 300 includes an electron source 1 (charged particle source), a deflection element 7 (deflector), 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 15-17 (detectors). The electron source 1 irradiates the sample 10 with a charged particle beam 201. The deflection element 7 separates the charged particle beam 201 from the signal electrons generated based on the charged particle beam irradiating the sample 10. The energy filter 14 filters the signal electrons based on their energy level. The signal electron control lens 12 parallelizes the direction of propagation of the signal electrons separated by the deflection element 7 and directs them into the energy filter 14. The signal electron control lens 13 focuses the signal electrons that have passed through the energy filter 14. Detectors 15-17 detect the signal electrons that have passed through the signal electron control lens 13. The following describes the configuration of the imaging unit 300 in more detail, with reference to Figure 2.

[0027] The imaging unit 300 has a primary optical system 301 and a secondary optical system 302 as its electron optical system. The primary optical system 301 performs a series of controls until electrons emitted from the electron source 1 reach the sample 10. The secondary optical system 302 controls signal electrons generated by the interaction between the charged particle beam 201 (hereinafter referred to as "primary beam 201") irradiated from the primary optical system 301 and the sample 10. A deflection element 7 is placed at the junction of the primary optical system 301 and the secondary optical system 302 to deflect the signal electrons towards the secondary optical system 302 and guide them to the detectors 15-17.

[0028] The dashed lines in Figure 2, representing the central axes 101 and 102, are the mechanical central axes of the columns of the primary optical system 301 and the secondary optical system 302, respectively. In Figure 2, the primary beam 201 is shown as a thick line, the trajectory 202, which spreads according to the emission angle of signal electrons generated from the center of the sample 10, is shown as a dotted line, and the signal electrons 203, which are emitted perpendicularly away from the sample 10 as a result of sample scanning, are shown as a solid line. The emission angle of the signal electrons will be treated as 0 degrees when emitted parallel to the central axis 101 and toward the electron source 1 from the sample 10. Furthermore, signal electrons generated spreading out according to the emission angle from the same location on the sample 10 will be treated as signal electron A (first signal electron), and signal electrons generated in the direction of 0 degrees emission angle from different positions on the sample 10 as a result of sample scanning will be treated as signal electron B (second signal electron).

[0029] The primary optical system 301 includes, between the electron source 1 and the sample 10, an extraction electrode 2 for drawing electrons from the electron source 1, an accelerating 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 scanning deflector 8 for scanning the sample 10, and an objective lens 9 for focusing the primary beam 201 onto the sample 10. The sample 10 is placed on a stage 11. The stage 11 moves in the planar and height directions, in the direction for adjusting the angle of the stage surface, and in the rotational direction for rotating the stage 11, etc., by a stage movement mechanism 110.

[0030] In the secondary optical system 302, two signal electronic control lenses and an energy filter 14 are arranged between the deflection element 7 and the detectors 15-17. At least two signal electronic control lenses are required, but three or more signal electronic control lenses may be provided. In this embodiment, the case in which two signal electronic control lenses, signal electronic control lens 12 and signal electronic control lens 13, are provided in the secondary optical system 302 will be described.

[0031] In addition to the configuration shown in Figure 2, the primary optical system 301 may also include an astigmatism corrector, a multi-stage lens, a detector, and other optical elements that act on the primary beam 201 or the orbits 202 and 203 of the signal electrons.

[0032] Furthermore, the imaging unit 300 includes, in this embodiment, detectors: detector 15 (first detector), detector 16 (second detector), and detector 17 (third detector). The signal electron detection surfaces of detectors 15, 16, and 17 are each positioned facing the filter surface of the energy filter 14. Detector 16 is positioned to face the central part of the energy filter 14. Detectors 15 and 17 are positioned so as to sandwich detector 16 and face different ends of the energy filter 14.

[0033] Furthermore, although the detector installed in the secondary optical system 302 is composed of three direct detectors (detectors 15-17) in Figure 2, the effectiveness of the technology of this disclosure is not lost even if the number of detectors is different, more specifically, four or more. Figure 3 shows an example where the detector is composed of five detectors 151, 15, 16, 17, and 171.

[0034] Furthermore, some or all of the detectors may be changed to indirect detectors or segmented detectors. Figure 4 shows an example where some of the detectors are indirect detectors. As shown in Figure 4, detector 16 is a direct detector, and detectors 15A and 17A are indirect detectors. Detectors 15A and 17A, which are indirect detectors, indirectly detect reflected electrons that are reflected when signal electrons collide with the signal electron conversion member 28, or tertiary electrons generated from the signal electron conversion member 28. Figure 5 shows an example where the detection unit is segmented. As shown in Figure 5, one detector 16A is divided into four parts 16A1 to 16A4, and signal electrons are detected in each of the segmented parts 16A1 to 16A4.

[0035] In addition, the shape of the signal-electron conversion member 28 is not limited to the plate shape shown in Figure 4 described above. Figures 6 to 8 show modified examples of the signal-electron conversion member 28. Figure 6 is an example where the signal-electron conversion member 28 is a pipe-shaped signal-electron conversion member 28A. Figure 7 is an example where the signal-electron conversion member 28 is a mortar-shaped signal-electron conversion member 28B that is axially symmetric with respect to the central axis 102 of the secondary optical system 302. Figure 8 is an example where partitions 29 corresponding to each detector 15A, 16, and 17A are added. By providing the signal-electron conversion members 28A, 28B or partitions 29 in this way, the signal discrimination performance of each detector can be improved.

[0036] Furthermore, although the energy filter 14 is shown as a plate-shaped mesh filter in Figure 1, it can be any structure that forms equipotential surfaces in at least a certain angular direction with respect to the orbits of the signal electrons B, for example, an annular energy filter. The certain angular direction is preferably the vertical direction.

[0037] The computer system 401 controls the operation of the imaging unit 300 and the stage movement mechanism 110. The computer system 401 performs processes such as controlling the intensity of the signal electronic control lens 12 and the signal electronic control lens 13. More specifically, the computer system 401 performs processes 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 (perpendicular in this embodiment), and changing the intensity of the signal electronic control lens 13 so that signal electrons that have passed through the energy filter 14 are focused on the detectors 15-17. The computer system 401 includes, for example, a control unit 402, a signal processing unit 403, an input / output unit 404, and a storage unit 405. In the computer system 401, the communication unit and other components are not shown in the illustration.

[0038] The control unit 402 includes, for example, a processor, ROM, RAM, etc. In addition to controlling operations such as scanning the target of observation of the sample 10 in the imaging unit 300 within the imaging range and the operation of the stage movement mechanism 110, the control unit 402 also performs operations to determine the intensity of the signal electronic control lenses 12 and 13, which will be described later with reference to Figure 13.

[0039] The signal processing unit 403 generates a detection image, such as a SEM image, based on the signal electrons output from the detectors 15-17. The signal processing unit 403 generates SEM image data by storing the detection signal in a frame memory or the like, for example, in synchronization with the scanning of a scanning deflector (not shown).

[0040] The input / output unit 404 includes, for example, input devices such as a keyboard and mouse, and display devices such as a display. The operator operates the input devices of the input / output unit 404 to input various instructions to the charged particle beam apparatus 100. The operator also views various information displayed on the display device of the input / output unit 404, such as SEM images.

[0041] The storage unit 405 is, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The storage unit 405 also functions as a non-temporary recording medium that stores, for example, a program for implementing the process of determining the intensity of the signal electronic control lenses 12 and 13.

[0042] <Sample imaging process> In this embodiment, the primary beam 201 is drawn out from the electron source 1 by the extraction electrode 2 and accelerated by the accelerating electrode 3. Subsequently, the primary beam 201 is adjusted by the aperture angle determination lens 4 so that the required region 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 moved away from the central axis 101 of the primary optical system using the scanning deflector 8, and the imaging range of the sample 10 is scanned.

[0043] Signal electrons generated from the sample 10 are pulled up and separated into the secondary optical system 302 by the deflection element 7. In order to achieve high-resolution energy filtering, it is necessary to always have the signal electrons B incident on the energy filter 14 at the same angle. In this embodiment, the signal electron control lens 12 in the preceding stage controls the signal electrons B so that they are always perpendicular to the energy filter 14. After passing through the energy filter 14, the signal electrons B are controlled by the signal electron control lens 13 in the subsequent stage to be focused on detectors 15-17. Signal electrons B are incident on detector 16, and signal electrons A are incident on detectors 15-17. Therefore, in this embodiment, a top-down image is acquired at detector 16, which is closest to the central axis 102 of the secondary optical system, and a shadow image is acquired at detectors 15 and 17.

[0044] <Control of the lens and energy filter for the first signal electronic control> Next, the control of the signal electron control lens 12 and the energy filter 14 will be described. As previously mentioned, in order to achieve high-resolution energy filtering, the signal electrons B must 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 electrons B perpendicular to the energy filter 14 using the signal electron control lens 12, but it is not necessarily required to be perpendicular. What is important in this embodiment is that the signal electrons B are incident on the energy filter 14 at the same angle. In other words, it is sufficient to control the signal electrons B so that they are incident on the energy filter 14 at a constant angle.

[0045] <Control of the lens for the second signal electronic control> Next, the control of the signal electron control lens 13 will be explained. Figure 9 is an example of a schematic diagram of an SEM image V1 in which shading occurs. Figure 10 is an example of a schematic diagram of an SEM image V2 in which shading is suppressed. Figures 11 and 12 show the trajectories of signal electrons A when acquiring SEM images V1 and V2 in Figures 9 and 10, respectively. Note that in Figures 11 and 12, only the secondary optical system 302 is shown, with the trajectory 204 spreading from the center of the sample 10 shown as a dotted line, and the trajectory 205 spreading from a point far from the center of the sample shown as a dashed line.

[0046] As shown in Figures 9 and 10, a low-step structure M1 is formed in sample 10 for observation. The low-step structure M1 is a structure in which a cross-shaped recess is formed when viewed from above.

[0047] To suppress the shading shown in Figure 9, it is necessary to reduce the difference in signal intensity acquired by the detector 16 when scanning the central and peripheral parts of the field of view. However, as shown in Figure 11, the amount of signal electrons A incident on the detector 16 differs between the central and peripheral parts of the field of view, resulting in a difference in signal intensity. To reduce this difference in signal intensity, as shown in Figure 12, it is necessary to appropriately set the intensity of the signal electron control lens 13 so that, for example, signal electrons A at a certain angle from the sample 10 always incident on the detector 16, and the final arrival position of the signal electrons A does not change depending on the sample scanning, but only changes according to the exit angle from the sample 10.

[0048] The intensities of the signal electronic control lens 12 and the signal electronic control lens 13 may be determined by reading pre-calculated values ​​from a calculation table according to each optical condition, or they may be determined according to the type (material, structure) of the sample 10 and the type and size of the object to be observed.

[0049] <Process for determining the intensity of lenses used for signal electronic control> Next, the process for determining the intensity of the signal electronic control lenses 12 and 13 will be described. Figure 13 is a flowchart showing an example of the process for determining the intensity of the signal electronic control lenses 12 and 13. This process is achieved, for example, by the control unit 402 reading and executing a program stored in the storage unit 405.

[0050] When the optical conditions are set by the operator, the control unit 402 acquires the set optical conditions in step ST101. Next, in step ST102, the control unit 402 reads a calculation table that has been pre-calculated so that the signal electrons take the desired trajectory.

[0051] Next, in step ST103, the control unit 402 determines whether or not to perform additional adjustments to the intensity of the signal electronic control lenses (signal electronic control lens 12 and signal electronic control lens 13) based on the optical condition settings and calculation table. For example, the operator visually inspects the SEM image displayed on the display device of the input / output unit 404. The operator inputs whether or not adjustment is necessary by operating the input device of the input / output unit 404. Based on this input instruction, the control unit 402 makes the determination in step ST103.

[0052] If it is determined that no further adjustment of the signal electronic control lens is necessary (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.

[0053] If it is determined that additional adjustment of the signal electronic control lens is necessary (ST103:YES), the control unit 402 changes the intensity of the signal electronic control lens 12 (first signal electronic control lens) in step ST105. Next, in step ST106, the control unit 402 determines whether or not there is brightness unevenness in the acquired image, i.e., the SEM image captured by the imaging unit 300, when the energy filter 14 is operating. If it is determined that there is brightness unevenness (ST106:YES), the process returns to step ST105, and the control unit 402 changes the intensity of the signal electronic control lens 12 again.

[0054] For example, the operator visually inspects the SEM image displayed on the display device of the input / output unit 404. The operator visually inspects whether or not there are brightness irregularities in the SEM image and inputs the inspection result via the input device of the input / output unit 404. Based on this input instruction, the control unit 402 makes the determination in step ST106. The intensity change is adjusted, for example, based on the operator's input operation of the input device of the input / output unit 404, so that a trend of uneven brightness changes in the acquired image does not occur when the energy filter 14 is operating. As a result, the computer system 401 can obtain an image without brightness irregularities.

[0055] Furthermore, if it is determined that there is no brightness unevenness (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, in step ST108, the control unit 402 determines whether the focal position is at the detector position. More specifically, the control unit 402 determines whether the focal position of the signal electrons that have passed through the signal electronic control lens 13 matches the detection surface of the detectors 15-17. 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.

[0056] For example, the operator visually inspects the SEM image displayed on the display device of the input / output unit 404. The operator visually inspects whether the imaging range is clearly visible in the SEM image and inputs the inspection result via the input device of the input / output unit 404. The control unit 402 makes the determination in step ST108 based on the input instruction. The intensity is changed, for example, based on the operator's input operation of the input device of the input / output unit 404, so that the acquired image is clear. As a result, the charged particle beam apparatus 100 can align the detector position with the focus of the signal electrons and obtain a clear SEM image.

[0057] Next, in step ST109, the control unit 402 determines the intensity of the signal electronic control lens 12 and the signal electronic control lens 13. That is, the intensity of the signal electronic control lens 12 determined by the processing in steps ST105 and ST106, and the intensity of the signal electronic control lens 13 determined by the processing in steps ST107 and ST108 are determined as the final intensity of the signal electronic control lens 12 and the signal electronic control lens 13.

[0058] <Inspection using a charged particle beam device> Next, a means for inspecting a sample 10 using the charged particle beam apparatus 100 will be described. When an operator inspects a desired sample 10, the operator first sets the optical conditions of the imaging unit 300 using the input / output unit 404. Based on the setting of the optical conditions, the voltage of the extraction electrode 2 and the voltage of the accelerating electrode 3 are changed according to a calculation table, and the lens of the primary optical system 301 is appropriately adjusted accordingly. The means for measuring the sample 10 and other objects using the charged particle beam apparatus are similar.

[0059] Subsequently, the deflection element 7 is set so that signal electrons generated perpendicularly from the center of the sample 10 are incident on the center of the detector 16.

[0060] Next, the signal electrons emitted perpendicularly from the sample 10 become parallel at the position of the energy filter 14, due to the signal electron control lens 12 and the signal electron control lens 13. The parallel signal electrons are then focused at the detector position. While maintaining this state, the intensity of the energy filter 14 is changed according to the sample 10 (or object of observation), and the charged particle beam apparatus 100 performs imaging until the desired image is obtained.

[0061] As described above, the charged particle beam apparatus 100 can achieve high-resolution energy filtering while suppressing shading caused by sample scanning during imaging of the sample 10. In other words, the charged particle beam apparatus 100 can achieve both a reduction in shading caused by sample scanning and high-resolution energy filtering.

[0062] Therefore, the charged particle beam apparatus 100 can enable a wider field of view and improved discriminability of observed objects by selectively detecting the angle or energy of signal electrons while suppressing shading. As a result, the charged particle beam apparatus 100 can also achieve faster inspection and measurement.

[0063] [Second Embodiment] <Configuration of the imaging unit of a charged particle beam apparatus> First, the imaging unit 310 of the charged particle beam apparatus 100 will be described with reference to Figure 14. Figure 14 is a diagram for schematicly illustrating the configuration of the imaging unit 310 of the charged particle beam apparatus 100. The overall configuration of the charged particle beam apparatus 100 is the same as that shown in Figure 1. In other words, in the second embodiment, the imaging unit 310 shown in Figure 14 is provided in the charged particle beam apparatus 100 instead of the imaging unit 300 shown in Figure 2 described above.

[0064] As shown in Figure 14, the primary optical system 311 of the imaging unit 310 has a similar configuration to the primary optical system 301 shown in Figure 2. The secondary optical system 312 controls the signal electrons generated by the interaction between the primary beam 201 and the sample 10.

[0065] In the secondary optical system 312, at least three signal electronic control lenses are arranged between the deflection element 7 and the detectors 15-17. In this embodiment, signal electronic control lenses 18, 19, and 20 are arranged. Compared to the case in Figure 2, the imaging unit 310 does not have an energy filter 14.

[0066] In this embodiment, after the signal electrons are incident on the secondary optical system 312, the signal electron control lens 18 focuses the signal electrons B onto the signal electron control lens 19. Furthermore, the signal electron control lens 19 acts only on the signal electrons A, controlling the angle of the signal electrons reaching the detectors 15-17. In addition, the signal electron control lens 20 operates to focus the signal electrons B, which have been spread out 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 shown in Figure 14, signal electrons B with a larger emission angle will be incident on the detector 16. In this embodiment, changing the emission angle of the signal electrons B acquired by the detectors 15-17 can be done by the computer system 401 controlling only the signal electron control lens 19.

[0067] Next, an example will be described in which the object of observation is a hole M2 formed on the sample 10. Figures 15 and 16 are schematic diagrams showing examples of SEM images V3 and V4, which are top-down images of the hole M2 and the hole bottom M2B, and are examples of cases in which signal electrons A are focused by the signal electron control lens 19 and acquired by the detector 16. Figures 17 and 18 are schematic diagrams showing examples of cross-sections of the sample 10 when observing the SEM images V3 and V4 shown in Figures 15 and 16, and are examples of cases in which signal electrons A are diverged by the signal electron control lens 19 and only the vertical component is acquired by the detector 16.

[0068] As shown in Figure 17, consider the case where all signal electrons 601-603 generated from the sample 10 are detected. In this case, signal electrons 602, which have a large emission angle and are generated from hole M2 at the bottom M2B, are blocked by the side wall of hole M2 and are not emitted upward. Therefore, only signal electrons 603, which have a smaller emission angle than signal electrons 602, can be detected by the detector 16. Consequently, the amount of signal detected from hole M2, which is the object of observation, is lower than the amount of signal electrons 601 generated from around hole M2. Therefore, the charged particle beam apparatus 100 can improve the discriminative ability of hole M2 by having the computer system 401 control the intensity of the signal electron control lens 19 and limiting the angle of the signal electrons detected by the detector to an angle below a certain level, as shown in Figure 18.

[0069] Next, as another example, we will describe the case where a low-step structure is used as the object of observation and imaging. The low-step structure M1 is a structure in which a cross-shaped recess is formed when viewed from above, similar to the case in Figure 9. Figure 19 is a schematic diagram showing an example of an SEM image V5 showing a shaded image of the low-step structure M1. Figure 20 is a schematic diagram showing an example of an SEM image V6 showing a shaded image acquired by enhancing the contrast of the shading using the technique of this embodiment. Figures 21 and 22 are schematic diagrams showing examples of the trajectories 207 of signal electron A and 206 of signal electron B generated from the center of the sample 10 during imaging in Figures 19 and 20, respectively. Note that Figures 21 and 22 show the trajectories of signal electrons in the secondary optical system 312 of the second embodiment, with the trajectory 207 of signal electron A generated from the center of the sample 10 shown as a dotted line and the trajectory 206 of signal electron B shown as a solid line.

[0070] When imaging a low-step structure M1, as shown in Figure 19, the computer system 401 may not be able to detect the low-step structure M1, which is the target of observation, because the contrast of the shadow of the low-step structure M1 is weak. To enhance the contrast of the shadow, it is sufficient to form a shadow image using only signal electrons with a larger emission angle. Therefore, the computer system 401 controls the intensity of the signal electron control lens 19 so that only a portion of the trajectory 207 of signal electron A enters the detectors 15 and 17. This enables the computer system 401 to enhance the contrast of the shadow and acquire the SEM image V6 shown in Figure 20.

[0071] As explained above, by having the operator control the angle of the signal electrons acquired by the detectors 15-17 by operating the input device of the input / output unit 404 in accordance with the state of the SEM image of the object being observed, the charged particle beam apparatus 100 becomes capable of generating the image desired by the operator.

[0072] The computer system 401 may determine the intensity of the signal electronic control lenses 18-20 from calculated values ​​calculated in advance according to each optical condition, or it may determine it according to the type and material of the sample 10 and the shape of the object to be observed.

[0073] <Process for determining the intensity of lenses used for signal electronic control> Next, the process for determining the intensity of the signal electronic control lenses 18-20 will be described. Figure 23 is a flowchart showing an example of the process for determining the intensity of the signal electronic control lenses 18-20. This process is achieved, for example, by the control unit 402 reading and executing a program stored in the storage unit 405.

[0074] As the optical conditions are set by the operator, the control unit 402 acquires the optical condition settings in step ST201, reads a calculation table that has been pre-calculated to ensure that the signal electrons follow the desired trajectory in step ST202, and determines in step ST203 whether or not to perform additional intensity adjustments, which are the same as steps ST101 to ST103 described above. If it is determined that no additional adjustment of the signal electron control lenses is necessary (ST203: NO), the control unit 402 determines the intensity of the signal electron control lenses 18 to 20 (third to fifth signal electron control lenses) in step ST204.

[0075] If it is determined that additional adjustment of the signal electronic control lens is necessary (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, in step ST206, the control unit 402 determines whether or not there is brightness unevenness in the SEM image captured by the imaging unit 310. If it is determined that there is brightness unevenness (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 those described in steps ST105 and ST106.

[0076] If it is determined that there is no brightness unevenness (ST206:NO), the control unit 402 changes the intensity of the signal electronic control lens 20 (fifth signal electronic control lens) in step ST207. Next, in step ST208, the control unit 402 determines whether the focal position is at the detector position. If it is determined that the focal 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 in steps ST107 and ST108 described above.

[0077] If it is determined that the focal point is at the detector position (ST208:YES), the control unit 402 changes the intensity of the signal electronic control lens 19 (fourth signal electronic control lens) in step ST209. Next, in step ST210, the control unit 402 determines whether or not the desired image has been obtained. 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.

[0078] For example, the operator visually inspects the SEM image displayed on the display device of the input / output unit 404. The operator inputs whether or not adjustment is necessary by operating the input device of the input / output unit 404. Based on this input instruction, the control unit 402 makes the determination in step ST210. The intensity is changed, for example, based on the operator's operation of the input / output unit 404. This allows the computer system 401 to obtain the image desired by the user.

[0079] If 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 18-20 in step ST211. The intensity thus determined becomes the final intensity of the signal electronic control lenses 18-20.

[0080] As explained above, the charged particle beam apparatus 100 can suppress shading caused by sample scanning while allowing selection of the angle of signal electrons acquired by detectors 15-17. In other words, the charged particle beam apparatus 100 can achieve both a reduction in shading caused by sample scanning and control of the angle of signal electrons.

[0081] [Third Embodiment] The third embodiment is an embodiment that combines the first and second embodiments. It will be described in detail below.

[0082] <Configuration of the imaging unit of a charged particle beam apparatus> First, the imaging unit 320 of the charged particle beam apparatus 100 will be described with reference to Figure 24. Figure 24 is a diagram for schematic explanation of the configuration of the imaging unit 320 of the charged particle beam apparatus 100. The overall configuration of the charged particle beam apparatus 100 is the same as that shown in Figure 1. In other words, in the third embodiment, the imaging unit 320 shown in Figure 24 is provided in the charged particle beam apparatus 100 instead of the imaging unit 300 shown in Figure 2 described above.

[0083] As shown in Figure 24, the primary optical system 321 of the imaging unit 320 has the same configuration as the primary optical system 301 shown in Figure 2. The secondary optical system 322 controls the signal electrons generated by the interaction between the primary beam 201 and the sample 10.

[0084] In the secondary optical system 322, at least four signal electronic control lenses are arranged between the deflection element 7 and the detectors 15-17. In this embodiment, four signal electronic control lenses, 21-24 (6th-9th signal electronic control lenses: 1st-4th lenses), are arranged. Furthermore, an energy filter 25 is arranged in the secondary optical system 322 between signal electronic control lens 21 and signal electronic control lens 22.

[0085] The detection surfaces of detectors 15, 16, and 17 for detecting signal electrons are each positioned facing the filter surface of the energy filter 25. Detector 16 is positioned to face the central part of the energy filter 25. Detectors 15 and 17 are positioned so as to sandwich detector 16 and face different ends of the energy filter 25. Signal electron B is detected by detector 16, and signal electron A is detected by detectors 15 to 17, as in the previously described embodiment.

[0086] The signal electron control lens 21 is a lens that parallelizes the signal electrons B. The signal electron control lens 22 is a lens that focuses the signal electrons B. The signal electron control lens 23 is a lens that controls the angle of the signal electrons reaching the detector. The signal electron control lens 24 is a lens that focuses the signal electrons B.

[0087] After the signal electrons enter the secondary optical system 322, the signal electrons B are propagated so that they are always perpendicular to the energy filter 25 by the control of the preceding signal electron control lens 21 by the computer system 401. After passing through the energy filter 25, the signal electrons B are focused to the center of the signal electron control lens 23 by the control of the subsequent signal electron control lens 22 by the computer system 401, and then focused again by the detector 16 by the control of the subsequent signal electron control lens 24 by the computer system 401.

[0088] While maintaining this state, the computer system 401 changes the intensity of the signal electron control lens 23 and the energy filter 25, allowing the charged particle beam apparatus 100 to control the emission angle and emission energy of the signal electrons A acquired by the detectors 15-17 while keeping the signal electrons B focused at the detector position.

[0089] <Process for determining the intensity of lenses used for signal electronic control> Next, the process for determining the intensity of the signal electronic control lenses 21-24 will be described. Figure 25 is a flowchart showing an example of the process for determining the intensity of the signal electronic control lenses 21-24. This process is achieved, for example, by the control unit 402 reading and executing a program stored in the storage unit 405.

[0090] As the optical conditions are set by the operator, the control unit 402 acquires the optical condition settings in step ST301, reads a calculation table that has been pre-calculated to ensure that the signal electrons follow the desired trajectory in step ST302, and determines in step ST303 whether or not to perform additional intensity adjustments, which are the same processes as described in steps ST101 to ST103. If it is determined that no additional adjustment of the signal electron control lenses is necessary (ST303: NO), the control unit 402 determines the intensity of the signal electron control lenses 21 to 24 (6th to 9th signal electron control lenses) in step ST304.

[0091] If it is determined that additional adjustment of the signal electronic control lens is necessary (ST303:YES), the control unit 402 changes the intensity of the signal electronic control lens 21 (sixth signal electronic control lens) in step ST305. Next, in step ST306, the control unit 402 determines whether or not there is brightness unevenness in the SEM image captured by the imaging unit 320. If it is determined that there is brightness unevenness (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 those described in steps ST105 and ST106.

[0092] If it is determined that there is no brightness unevenness (ST306: NO), the control unit 402 changes the intensity of the signal electronic control lens 22 (seventh signal electronic control lens) in step ST307. Next, in step ST308, the control unit 402 determines whether or not brightness unevenness occurs when the energy filter 25 is operating. If it is determined that brightness unevenness 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.

[0093] For example, the operator visually inspects the SEM image displayed on the display device of the input / output unit 404. The operator operates the energy filter 25 and visually inspects whether or not brightness unevenness occurs in the SEM image when the energy filter 25 is operating, and inputs the inspection result via the input device of the input / output unit 404. The control unit 402 makes the determination in step ST308 based on the input instruction. The intensity change is modified, for example, based on the operator's input operation of the input / output unit 404, so as to reduce the change in brightness of the SEM image. As a result, the charged particle beam apparatus 100 can prevent a trend of unevenness in the brightness change of the SEM image when the energy filter 25 is operating.

[0094] If it is determined that there is no brightness unevenness (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, in step ST310, the control unit 402 determines whether the focal position is at the detection position. If it is determined that the focal 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 in steps ST107 and ST108 described above.

[0095] If it is determined that the focal point is at the detection position (ST310: YES), the control unit 402 changes the intensity of the signal electronic control lens 23 (8th signal electronic control lens) in step ST311. Next, in step ST312, the control unit 402 determines whether or not the desired image has been obtained. 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 those described in steps ST209 and ST210.

[0096] If 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 21-24 in step ST313. This determined intensity becomes the final intensity of the signal electronic control lenses 21-24.

[0097] By determining the intensity of the signal electron control lenses 21-24 in this way, the charged particle beam apparatus 100 can suppress shading caused by sample scanning, select the angle of the signal electrons acquired by the detectors 15-17, and selectively detect the angle and energy of the signal electrons. Even with this configuration, the charged particle beam apparatus 100 can achieve a wider field of view and improved discriminability of the observed object.

[0098] <Variation> Next, a modified example of the third embodiment will be described. In this modified example, the secondary optical system 322 shown in Figure 24 is transformed into the secondary optical system 332 shown in Figure 26.

[0099] <Configuration of the imaging unit of a charged particle beam apparatus> First, the imaging unit 330 of the charged particle beam apparatus will be described with reference to Figure 26. Figure 26 is a diagram that schematically illustrates the configuration of the imaging unit 330 of the charged particle beam apparatus 100. The overall configuration of the charged particle beam apparatus 100 is the same as that shown in Figure 1.

[0100] As shown in Figure 26, the secondary optical system 332, compared to the secondary optical system 322 shown in Figure 24, has the same signal electronic control lenses 21-24, but the position of the energy filter 25 is different. In the secondary optical system 332, the energy filter 25 is positioned between the signal electronic control lens 23 and the signal electronic control lens 24.

[0101] The signal electron control lens 21 focuses the signal electrons B. The signal electron control lens 22 controls the angle of the signal electrons reaching the detector. The signal electron control lens 23 parallelizes the signal electrons B. The signal electron control lens 24 focuses the signal electrons B to the detector position.

[0102] <Process for determining the intensity of lenses used for signal electronic control> Next, the process for determining the intensity of the signal electronic control lenses 21-24 will be described. Figure 27 is a flowchart showing an example of the process for determining the intensity of the signal electronic control lenses 21-24. This process is achieved, for example, by the control unit 402 reading and executing a program stored in the storage unit 405.

[0103] The processes in steps ST401 to ST404 are identical to those in steps ST301 to ST304 described above. Therefore, the explanation of the processes in steps ST401 to ST404 will be omitted. As in the third embodiment, the intensity of the signal electronic control lenses 21 to 24 is adjusted by the operator operating the input / output unit 404.

[0104] The control unit 402 modifies the intensity of the signal electronic control lens 21 (sixth signal electronic control lens) in steps ST405 and ST406 to suppress brightness unevenness in the SEM image during imaging. As a result, the computer system 401 can suppress brightness unevenness in the SEM image during imaging.

[0105] Next, the control unit 402 modifies the intensity of the signal electronic control lens 23 (eighth signal electronic control lens) in steps ST407 and ST408 so that when the energy filter 25 is operating, a tendency for brightness unevenness to occur in the captured SEM image. This allows the computer system 401 to prevent brightness unevenness from occurring when the energy filter 25 is operating.

[0106] Next, the control unit 402 modifies the intensity of the signal electron control lens 24 (the ninth signal electron control lens) in steps ST409 and ST410 to align the detector position with the focal point of the signal electrons. This allows the computer system 401 to align the detector position with the focal point of the signal electrons.

[0107] Next, the control unit 402 changes the intensity of the signal electronic control lens 22 (seventh signal electronic control lens) in steps ST411, ST412, and ST413 so that the desired image can be obtained. These processes are the same as those described in steps ST311, ST312, and ST313.

[0108] As described above, even when using an imaging unit 330 that includes a secondary optical system 332, the charged particle beam apparatus 100, similar to the third embodiment, can suppress shading due to sample scanning, select the angle of signal electrons acquired by detectors 15-17, and selectively detect the angle and energy of signal electrons. Even with this configuration, the charged particle beam apparatus 100 can achieve a wider field of view and improved discriminability of the observed target.

[0109] [Fourth Embodiment] In the fourth embodiment, a field-of-view selector and an aperture are added to the secondary optical system 322 of the imaging unit 320 of the charged particle beam apparatus 100 of the third embodiment, and the detector configuration is further modified.

[0110] <Configuration of the imaging unit of a charged particle beam apparatus> First, the imaging unit 340 of the charged particle beam apparatus 100 will be described with reference to Figure 28. Figure 28 is a diagram that schematically illustrates the configuration of the imaging unit 340 of the charged particle beam apparatus 100. The overall configuration of the charged particle beam apparatus 100 is the same as that shown in Figure 1. The following description will focus on the secondary optical system 342 of the imaging unit 340.

[0111] As shown in Figure 28, the configuration of the three detectors differs from that in Figure 24. Specifically, the detection surface of detector 16 is positioned opposite the filter surface of the energy filter 25. The detection surfaces of detectors 15A and 17A are positioned at a different angle (90 degrees: perpendicular in this embodiment) than the filter surface of the energy filter 25, and their respective detection surfaces are positioned opposite each other. Signal electron B is detected by detector 16, and signal electron A is detected by detectors 15A, 16, and 17A. In other words, the configuration of the three detectors is the same as that of detectors 15A, 16, and 17A described using Figure 4.

[0112] Furthermore, a field-of-view deflector 26 and an aperture 27 are added between the signal electronic control lens 24 and the detectors 15A, 16, and 17A. The computer system 401 can control the deflection of the deflector 26 and the aperture of the aperture 27 based on the operator's input / output unit 404. The computer system 401 can operate the aperture 27 and the field-of-view deflector 26 and detect the energy spectrum using the signal electrons B detected by the detector 16.

[0113] Next, the method for acquiring the energy spectrum will be described. The signal electron control lenses 21-24 operate in the same manner as described in the third embodiment. In this embodiment, the computer system 401 controls the intensity of the signal electron control lens 24 based on the operator's input to prevent the signal electrons B from being focused at the detector position. Subsequently, the computer system 401 controls the deflection of the field-of-view selector 26 to deaxialize the signal electrons B, and the operator selects the signal electrons at the location where they wish to acquire the energy spectrum using the aperture 27.

[0114] While maintaining this state, the computer system 401 changes the intensity of the energy filter 25 and measures the signal amount of signal electrons incident on the detector 16. Subsequently, the computer system 401 can obtain an energy spectrum by correlating the intensity of the energy filter 25 with the signal amount detected by the detector 16.

[0115] Furthermore, the computer system 401 can change the region during energy spectrum acquisition by controlling the spread of signal electrons B with the signal electron control lens 24. This allows the computer system 401 to acquire the energy spectrum of the deflected region.

[0116] Furthermore, the computer system 401 can display the acquired energy spectrum on the input / output unit 404. This allows the operator to visually inspect the energy spectrum of a desired region within the observation area.

[0117] As described above, the charged particle beam apparatus 100 allows the operator to specify a particular position or region of the object to be observed after imaging with a wide field of view, and then acquire the energy spectrum of the observation area of ​​the sample 10.

[0118] Although embodiments of this disclosure have been described in detail above, the invention is not limited to the embodiments described above, and various modifications are possible without departing from the gist of the invention. Each embodiment allows for the addition, deletion, and replacement of components, except for essential components. Unless otherwise specified, each component may be singular or plural. Combinations of each embodiment and its variations are also possible. Each of the above-described configurations, functions, and processing units may be implemented in part or in whole in hardware, such as in the design of 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 can 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 Symbols]

[0119] 1…Electron source, 2…Extraction electrode, 3…Accelerating electrode, 4…Lens, 5…Aperture, 6…Focusing lens, 7…Declining element, 8…Decliner for scanning, 9…Objective lens, 10…Sample, 11…Stage, 12,13…Lenses for signal electron control, 14,25…Energy filter, 15~17…Detector, 18~24…Lenses for signal electron control, 26…Decliner for field of view selection, 27…Aperture, 28,28A,28B…Signal electron conversion component, 29…Partition plate, 100…Charged particle beam apparatus, 101…Central axis of the primary optical system, 102…Central axis of the secondary optical system, 201…Primary beam, 202…Emission angle of signal electrons generated from the center of the sample 203...Orbits that spread depending on the angle, 204...Orbits that spread depending on the emission angle of signal electrons generated from the center of the sample, 205...Orbits that spread depending on the emission angle of signal electrons generated from a point away from the center of the sample, 206...Orbits that spread depending on the emission angle of signal electrons generated from a point away from the center of the sample, 207...Orbits that spread depending on the emission angle of signal electrons generated from the center of the sample, 300, 310, 320, 330, 340...Imaging unit, 301...Primary optical system, 302, 312, 322, 332, 342...Secondary optical system, 401...Computer system, V1~V6...SEM images

Claims

1. A charged particle source that irradiates a sample with a charged particle beam, A deflector that separates the charged particle beam from the signal electrons generated based on the charged particle beam irradiated onto 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 propagation of the signal electrons separated by the deflector and directs them into 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, The system comprises a computer system for controlling the intensity of the first lens and the intensity of the second lens, The aforementioned computer system, The intensity of the first lens is changed so that the signal electrons are incident on the filter at a certain angle. The intensity of the second lens is changed so that the signal electrons that have passed through the filter are focused onto the detector. Charged particle beam device.

2. A charged particle beam apparatus according to claim 1, The aforementioned constant angle is the angle at which the direction of propagation of the signal electrons is perpendicular to the filter. Charged particle beam device.

3. A charged particle beam apparatus according to claim 1, The detector includes a first detector, a second detector, and a third detector. The detection surfaces of the signal electrons of the first detector, the second detector, and the third detector are each positioned opposite the filter surface of the filter. The second detector is positioned so as to face the center of the filter, The first detector and the third detector are arranged so as to sandwich the second detector and so as to face different ends of the filter, The signal electrons include first signal electrons that spread out according to the exit angle from the charged particle beam irradiated to the same location on the sample, and second signal electrons that are generated in the direction of the exit angle from different locations on the sample as the charged particle beam scans the sample. The second signal electron is detected by the second detector, The first signal electron is detected by the first detector, the second detector, and the third detector. Charged particle beam device.

4. A charged particle beam apparatus according to claim 3, A third lens that focuses the first signal electrons that have passed through the second lens onto the first detector, The system further comprises a fourth lens that focuses the second signal electrons that have passed through the second lens onto the second and third detectors, The computer system further controls the intensity of the third lens and the intensity of the fourth lens. Charged particle beam device.

5. A charged particle beam apparatus according to claim 1, The detector includes a first detector, a second detector, and a third detector. The detection surface of the second detector is positioned opposite the filter surface of the filter, The detection surfaces of the first detector and the third detector are arranged at a different angle from the filter surface, and their respective detection surfaces are arranged to face each other. The signal electrons include first signal electrons that spread out according to the exit angle from the charged particle beam irradiated to the same location on the sample, and second signal electrons that are generated in the direction of the exit angle from different locations on the sample as the charged particle beam scans the sample. The second signal electron is detected by the second detector, The first signal electron is detected by the first detector, the second detector and the third detector, The charged particle beam apparatus is A third lens that focuses the first signal electrons that have passed through the second lens onto the first detector, A fourth lens that focuses the second signal electrons that have passed through the second lens onto the second detector and the third detector, A diaphragm that narrows the signal electrons detected by the first detector, It further includes a field-of-view selection deflector that allows selection of the field of view, The computer system further controls the intensity of the third lens and the fourth lens, operates the aperture and the field-of-view selective deflector, and detects the energy spectrum using the first signal electrons detected by the second detector. Charged particle beam device.

6. A charged particle beam apparatus according to claim 1, The aforementioned computer system, The system has a display unit that displays an image generated based on the signal electrons detected by the detector. Charged particle beam device.

7. A charged particle beam apparatus according to claim 6, The aforementioned computer system, The device has an input unit for changing the intensity of the first lens and the second lens, Charged particle beam device.

8. A charged particle beam apparatus according to claim 7, The aforementioned computer system, Based on the instructions received from the input unit in accordance with the image displayed on the display unit, the intensity of at least one of the first lens and the second lens is changed. Charged particle beam device.

9. A charged particle source that irradiates a sample with a charged particle beam, A deflector that separates the charged particle beam from the signal electrons generated based on the charged particle beam irradiated onto 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 propagation of the signal electrons separated by the deflector and directs them into 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, A method for determining the lens intensity of a charged particle beam apparatus, comprising a computer system for controlling the intensity of the first lens and the intensity of the second lens, The lens intensity determination method described above is: The computer system modifies the intensity of the first lens so that the signal electrons are incident on the filter at a certain angle, The computer system includes the step of changing the intensity of the second lens so that the signal electrons that have passed through the filter are focused onto the detector. A method for determining the lens intensity of a charged particle beam apparatus.

Images