Charged particle beam device

Abstract

Provided is a charged particle beam device comprising: an extraction electrode that forms an electric field for extracting ions from an opening of a plasma ion source; a current-limiting diaphragm that narrows an ion beam extracted by the extraction electrode and adjusts a beam spot diameter formed on a sample and a beam current applied to the sample; and a control device that controls the voltage applied to the extraction electrode. The control device: stores a first voltage set for the applied voltage, a second voltage set lower than the first voltage, and a prescribed current set for the beam current of the ion beam; sets the applied voltage to the first voltage; drives the current-limiting diaphragm to control the beam spot diameter and change the beam current within a range of the prescribed current or more; and in a range where the beam current falls below the prescribed current, sets the applied voltage to the second voltage and reduces the beam spot diameter as compared with a case where the applied voltage is set to the first voltage.

Description

charged particle beam device

[0001] The present invention relates to a charged particle beam device equipped with a plasma ion source.

[0002] Charged particle beam devices include those using a plasma ion source, as described in Japanese Patent Laid-Open No. 2020-71904 (Patent Document 1). Charged particle beam devices using a plasma ion source can scan a sample with a higher current ion beam than conventional focused ion beam devices using a gallium ion source, which is a liquid metal light source, and can shorten the scanning time for large-volume samples.

[0003] Japanese Patent Application Laid-Open No. 2020-71904

[0004] Compared to charged particle beam devices using gallium ion sources, charged particle beam devices using plasma ion sources have the advantage of being able to irradiate a sample with a high-current ion beam. However, the large beam spot reduces the processing accuracy and the resolution of the observed image.

[0005] An object of the present invention is to provide a high-resolution charged particle beam device using a plasma ion source.

[0006] In order to achieve the above object, the present invention provides a charged particle beam device comprising: a plasma ion source; an extraction electrode that forms an electric field that extracts ions from an opening of the plasma ion source; a current-limiting aperture that limits the ion beam extracted by the extraction electrode and adjusts the beam spot diameter formed on a sample and the beam current irradiated onto the sample; and a control device that controls a voltage applied to the extraction electrode, wherein the control device stores a first voltage that is set for the applied voltage, a second voltage that is set lower than the first voltage, and a predetermined current that is set for the beam current of the ion beam, and sets the applied voltage to the first voltage and drives the current-limiting aperture to control the beam spot diameter and change the beam current within a range equal to or greater than the predetermined current, and sets the applied voltage to the second voltage when the beam current is below the predetermined current, thereby reducing the beam spot diameter compared to when the applied voltage is set to the first voltage.

[0007] According to the present invention, it is possible to improve the resolution of a charged particle beam device using a plasma ion source.

[0008] 1 is a schematic diagram of a charged particle beam device according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a power supply circuit for an extraction electrode provided in the charged particle beam device according to an embodiment of the present invention; FIG. 3 is a diagram schematically showing the shape of an ion emission surface at an aperture of a plasma ion source provided in the charged particle beam device according to an embodiment of the present invention in a high voltage mode; FIG. 4 is a diagram schematically showing the shape of an ion emission surface at an aperture of a plasma ion source provided in the charged particle beam device according to an embodiment of the present invention in a low voltage mode; and FIG. 5 is a diagram showing the relationship between the beam current and the beam spot diameter of an ion beam in the charged particle beam device according to an embodiment of the present invention.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] -Charged particle beam device- Figure 1 is a schematic diagram of a charged particle beam device according to one embodiment of the present invention. The charged particle beam device 1 shown in Figure 1 is a hybrid charged particle beam device (FIB-SEM) equipped with a plasma ion source 31, and is capable of processing and observing a sample S using an ion beam (FIB) extracted from a plasma, and of observing the sample S using an electron beam (EB). The charged particle beam device 1 can irradiate the sample S with a high-current ion beam IB, and the sample S can be, for example, a relatively large (e.g., 300 mm diameter) semiconductor wafer or other large-volume sample.

[0011] The charged particle beam device 1 includes a sample chamber 10, a stage (sample table) 20, an ion beam column 30, an electron beam column 40, a detector 50, and a control device 60. Although not shown in Fig. 1, the charged particle beam device 1 may also include a manipulator that supports a sample piece cut out from the sample S, a gas gun that emits a predetermined gas such as an etching gas or a deposition gas onto the sample S, and the like.

[0012] - Sample Chamber - During processing or observation of the sample S, the sample chamber 10, together with the ion beam column 30 and the electron beam column 40, is depressurized to a predetermined vacuum level.

[0013] -Stage- The stage 20 holds and fixes the sample S inside the sample chamber 10. The stage 20 includes a sample stage on which the sample S is placed and a mechanism for displacing the sample stage with five degrees of freedom. The mechanism for displacing the sample stage has, for example, five degrees of freedom and includes an XYZ movement mechanism for translating the sample stage along the X-, Y-, and Z-axes, a rotation mechanism for rotating the sample stage around the vertical Z-axis, and a tilt mechanism for rotating the sample stage around the horizontal X-axis (or Y-axis). The X-axis and Y-axis are two axes that are orthogonal to each other in a horizontal plane, and the Z-axis is orthogonal to the X-axis and Y-axis. By displacing the sample stage, the stage 20 moves a desired portion of the sample S to the beam spot of the ion beam IB or electron beam IB.

[0014] - Ion beam column - The ion beam column 30 is fixed to the sample chamber 10 and is used for processing or observing the sample S, and irradiates the sample S held on the stage 20 with an ion beam IB. While Fig. 1 shows an example of a configuration in which the ion beam column 30 is installed in the sample chamber 10 in a state inclined relative to the vertical, the ion beam column 30 may also be installed in the sample chamber 10 in a vertical position. The ion beam column 30 is controlled by a control device 60.

[0015] The ion beam column 30 includes a plasma ion source 31 , an extraction electrode 32 , a capacitor electrode (condenser lens) 33 , a current limiting aperture 34 , and a focus electrode (objective lens) 35 .

[0016] The plasma ion source 31 includes, for example, a plasma generation chamber (plasma generator) 31a (FIG. 2) that maintains plasma inside and allows ions to flow out, and a plasma aperture (plasma electrode) 31b (FIG. 2) that draws ions out of the plasma generation chamber 31a. A rare gas is used as the plasma gas that forms the plasma in the plasma ion source 31. The plasma gas is, for example, one or more gases selected from neon, argon, xenon, and krypton.

[0017] The extraction electrode 32 forms an electric field that extracts ions from the opening of the plasma ion source 31, i.e., the orifice 31c (FIG. 2) of the plasma aperture 31b. The extraction electrode 32 is disposed between the plasma ion source 31 and a capacitor electrode 33. The ions extracted from the plasma ion source 31 by the extraction electrode 32 are optically manipulated by the ion optical system and focused, and are then irradiated onto the sample S as an ion beam IB.

[0018] The ion optical system is equipped with the above-mentioned capacitor electrode 33, current-limiting aperture 34, and focus electrode 35, in that order from the plasma ion source 31 toward the sample chamber 10. The capacitor electrode 33 is an element that forms an electric field that collects ions extracted by the extraction electrode 32. The current-limiting aperture 34 is an element that narrows the ion beam IB extracted by the extraction electrode 32 and adjusts the diameter of the beam spot formed on the sample S and the beam current irradiated onto the sample S. The focus electrode 35 is an element that forms an electric field that focuses ions onto the sample S. In addition, although not shown, the ion optical system is equipped with an aligner, a polarizer, etc. The aligner is an element that adjusts the optical axis of the ion beam IB that has passed through the current-limiting aperture 34, for example. The polarizer is an element that scans the ion beam IB over the surface of the sample S.

[0019] -Electron Beam Column- The electron beam column 40 is fixed to the sample chamber 10 and used for observing the sample S. The electron beam column 40 scans the sample S held on the stage 20 by irradiating it with an electron beam extracted from an electron source by an extraction electrode. While FIG. 1 illustrates a configuration in which the electron beam column 40 is installed vertically in the sample chamber 10, the electron beam column 40 may also be installed in the sample chamber 10 at an angle relative to the vertical. The electron beam column 40 is controlled by a control device 60. The charged particle beam device 1 is also provided with a shutter 41 that opens and closes an outlet 42 (electron beam exit port) of the electron beam column 40. For example, by blocking the outlet 42 of the electron beam column 40 with the shutter 41 during processing of the sample S with the ion beam IB, the intrusion of spatter generated during processing into the electron beam column 40 is suppressed, and insulation deterioration of the electron beam column 40 is suppressed.

[0020] - Detector - The detector 50 detects secondary charged particles (secondary electrons, secondary ions, etc.) generated in the sample S by irradiation with the ion beam IB or electron beam.

[0021] -Control Device- The control device 60 is a computer having an arithmetic unit 60a (e.g., CPU) and a storage device 60b (e.g., RAM, ROM, HHD, SSD), and controls operating devices such as the ion beam column 30, the electron beam column 40, and the stage 20, and generates image data of an observation image (e.g., SIM image, SEM image) of the sample S by detecting secondary charged particles (e.g., secondary electrons) from the sample S and capturing the signal input from the detector 50 in synchronization with the scanning signal of the charged particle beam (ion beam IB or electron beam). The generated image data is stored in the storage device 60b and displayed appropriately on a display device 61 (e.g., monitor). In addition to the display device 61, an input device 62 (e.g., keyboard) is connected to the control device 60. For example, items and conditions related to processing and observation are input via the input device 60b and instructed to the control device 60. The control device 60 loads a program stored in the memory device 60b into the calculation device 60a and executes it, and according to instructions, irradiates the sample S with a charged particle beam to obtain an observation image of the sample S, or irradiates the sample S with an ion beam IB to process the sample S.

[0022] -Power supply circuit for extraction electrode- Fig. 2 is a schematic diagram of the power supply circuit for the extraction electrode. As shown in Fig. 2, the extraction electrode 32 is connected to the control device 60 via a power supply device 70. That is, the power supply device 70 is connected to the extraction electrode 32, and the control device 60 is connected to the power supply device 70.

[0023] The charged particle beam system 1 of this embodiment is provided with two beam modes for the ion beam IB: a low voltage mode and a high voltage mode. For example, in response to a predetermined operation of the input device 62, the control device 60 can cause the display device 61 to display a beam mode setting screen showing button A for selecting the low voltage mode and button B for selecting the high voltage mode. When the operator presses either button A or B to select and set the beam mode, the control device 60 controls the power supply device 70 in accordance with the selection to switch the extraction voltage applied to the extraction electrode 32 and switch the beam mode of the ion beam IB.

[0024] -Beam Mode- FIG. 3 is a diagram showing a schematic view of the shape of the ion emission surface at the opening of the plasma ion source in the high voltage mode, and FIG. 4 is a diagram showing a schematic view of the shape of the ion emission surface at the opening of the plasma ion source in the low voltage mode.

[0025] The plasma ion source 31 is characterized by a high angular current density. Due to this characteristic, the ion emission surface Ps of the plasma P at the opening of the plasma ion source 31 (the orifice 31c of the plasma aperture 31b) becomes more concave (convex toward the plasma ion source 31) as shown in Fig. 3 as the extraction voltage applied to the extraction electrode 32 increases. Conversely, the ion emission surface Ps becomes more convex (convex toward the sample S) as shown in Fig. 4 as the extraction voltage decreases.

[0026] During operation of the charged particle beam device 1, the sample chamber 10 and the ion beam column 30 are maintained in a high vacuum state. Therefore, the plasma P in the plasma generation chamber 31a is drawn into the sample chamber 10 and attempts to flow out of the plasma generation chamber 31a, even when no voltage is applied to the extraction electrode 32. Then, by applying an extraction voltage to the extraction electrode 32 while the plasma P is being generated in the plasma generation chamber 31a, ions are extracted from the plasma P attempting to flow out of the plasma generation chamber 31a and accelerated to form an ion beam IB. In an FIB device, the extraction voltage is typically set so that ions are extracted at a high density from the plasma P so that a high-current ion beam IB can be irradiated onto the sample S. In this case, the ion beam IB is extracted faster than the plasma P is drawn into the sample chamber 10. Therefore, at the opening of the plasma ion source 31 (the orifice 31c of the plasma aperture 31b), the ion emission surface Ps of the plasma P has a concave shape, as shown in FIG. 3 . The extraction voltage set so that the ion emission surface Ps has a concave shape is referred to as a first voltage V1. In contrast, the example shown in Figure 4 illustrates a state in which the extraction voltage is set to a second voltage V2 lower than the first voltage V1 so that the ion emission surface Ps of the plasma P has a convex shape.

[0027] As shown in FIG. 3 , ions are emitted from the concave ion emission surface Ps toward the sample S with a velocity component in a direction toward the optical axis C of the ion beam IB (inward in the beam radial direction). Therefore, the outer circumferential surface of the ion beam IB emitted from the concave ion emission surface Ps (the outline of the cross section of the ion beam IB including the optical axis C) has a concave, narrowed shape midway along the direction of extension of the optical axis C, as shown in the same figure. Conversely, as shown in FIG. 4 , ions are emitted from the convex ion emission surface Ps toward the sample S with a velocity component in a direction away from the optical axis C of the ion beam IB (outward in the beam radial direction). Therefore, the outer circumferential surface of the ion beam IB emitted from the convex ion emission surface Ps (the outline of the cross section of the ion beam IB including the optical axis C) has a convex, bulging shape midway along the direction of extension of the optical axis C, as shown in the same figure.

[0028] The source of the ion beam IB is projected onto the sample S as a beam spot. In the case of the ion beam IB extracted from the plasma P, the point where the trajectories of the individual ions or their extensions converge most densely is considered to be the virtual light source. In the case of the concavely constricted ion beam IB as shown in FIG. 3 , this virtual light source L corresponds to the constricted portion of the ion beam IB. In this case, the size of the cross section of the constricted portion of the ion beam IB cut along a plane perpendicular to the optical axis C corresponds to the size of the virtual light source L. On the other hand, in the case of the convexly convex ion beam IB as shown in FIG. 4 , the cross section of the extensions (two-dot chain lines) of the trajectories of the individual ions of the ion beam IB extending from the ion emission surface Ps toward the plasma ion source 31 (the opposite side to the sample S) corresponds to the virtual light source L. In this case, the size of the cross section of the focus of the ion trajectories cut along a plane perpendicular to the optical axis C corresponds to the size of the virtual light source L. Therefore, when the applied voltage is set to the first voltage V1 and the ion emission surface Ps has a concave shape, the virtual light source L of ions projected onto the sample S is located closer to the sample S than the extraction electrode 32. When the applied voltage is set to the second voltage V2 and the ion emission surface Ps has a convex shape, the virtual light source L is located closer to the plasma ion source 31 than the extraction electrode 32. Therefore, compared to when the applied voltage is set to the first voltage V1, when the applied voltage is set to the second voltage V2, the virtual light source L is farther from the sample S. Furthermore, compared to when the applied voltage is set to the first voltage V1 in FIG. 3 , the virtual light source L is smaller in FIG. 4 , where the applied voltage is set to the second voltage V2. For example, the virtual light source L in FIG. 4 is smaller than the opening diameter of the orifice 31c of the plasma aperture 31b. Thus, compared to when the applied voltage is set to the high voltage mode in FIG. 3 , in the low voltage mode in FIG. 4 , the virtual light source L is smaller and its distance from the sample S is longer, effectively reducing the optical magnification.

[0029] FIG. 5 is a graph (double logarithmic graph) showing the relationship between the beam current [μA] of the ion beam IB and the beam spot diameter [μm].

[0030] The beam current of the ion beam IB reaching the sample S is substantially proportional to the beam diameter of the ion beam IB, and the beam current decreases as the beam diameter increases. The beam current is adjusted mainly by the amount of ion beam IB blocked by the current-limiting aperture 34 ( FIG. 1 ). For example, the current-limiting aperture 34 is provided with a plurality of orifices with different opening diameters, and the beam diameter and spot diameter of the ion beam IB passing through the orifice change depending on the opening diameter of the selected orifice. The beam current of the ion beam IB reaching the sample S changes depending on the change in the opening diameter of the current-limiting aperture 34, i.e., the change in the beam diameter of the ion beam IB. Alternatively, the beam current value can also be adjusted by, for example, controlling the excitation of the focus electrode 35.

[0031] For high-resolution observation or processing, it is preferable to narrow the beam diameter of the ion beam IB. In this case, in high-voltage mode, the beam current and beam spot diameter are reduced by sequentially switching the orifices of the current-limiting aperture 34 to reduce the aperture diameter. However, the beam spot diameter is limited by factors such as the length of the ion beam column 30, and there is a limit to how much it can be reduced. Therefore, in high-voltage mode, when the beam current falls below a predetermined current Is (e.g., 10 pA), the beam spot diameter does not change even if the beam current is reduced, as shown by the solid line in FIG. 5 . The predetermined current Is corresponds to the beam current of the ion beam IB reaching the sample S when, for example, the first voltage V1 is applied to the extraction electrode 32 (i.e., in high-voltage mode) and the aperture of the current-limiting aperture 34 is set to the minimum (the smallest orifice is selected). However, the predetermined current Is used as a judgment value for switching between the high voltage mode and the low voltage mode does not necessarily have to be a value that depends on the orifice diameter of the current-limiting aperture 34, and a current value that is set in advance in consideration of the appropriateness of switching the beam mode can be adopted.

[0032] In this embodiment, in order to further reduce the beam spot diameter in the region where the beam current is below a predetermined current Is, the beam mode is switched to a low voltage mode, and the light source itself projected onto the sample S is reduced. In the low voltage mode, as shown by the dashed line in Fig. 5, the beam spot diameter is further reduced beyond the minimum beam spot diameter in the high voltage mode as the beam current decreases.

[0033] In the charged particle beam device 1, data relating to the relationship between beam current and beam spot diameter, as shown in FIG. 5 , which has been experimentally or theoretically determined in advance, is stored in the storage device 60b of the control device 60. For example, the storage device 60b stores the first voltage V1 set for the applied voltage, the second voltage V2 set lower than the first voltage V1, and the predetermined current Is set for the beam current of the ion beam IB. The control device 60 then reads these data and programs from the storage device 60b, and in a high-voltage mode in which the applied voltage is set to the first voltage V1, the control device 60 drives the current-limiting aperture 34 to control the beam spot diameter and change the beam current within a range equal to or greater than the predetermined current Is. In a low-voltage mode in which the applied voltage is set to the second voltage V2, the control device 60 can reduce the beam spot diameter compared to the high-voltage mode when the beam current is below the predetermined current Is. For example, the control device 60 controls the beam current based on the relationship shown in FIG. 5 in accordance with the beam mode and beam spot diameter input via the input device 62. The control device 60 can also be configured so that the beam mode is automatically switched in accordance with the input beam spot diameter or beam current.

[0034] Effect (1) In this embodiment, the voltage applied to the extraction electrode 32 is set to a first voltage V1 to drive the current-limiting aperture 34, thereby controlling the beam spot diameter and varying the beam current within a range equal to or greater than a predetermined current Is. Furthermore, when the beam current is below the predetermined current Is, the voltage applied to the extraction electrode 32 is set to a second voltage V2, which is lower than the first voltage V1, to reduce the beam spot diameter compared to when the applied voltage is set to the first voltage V1. In other words, by lowering the voltage applied to the extraction electrode 32 to the second voltage V2 (switching to the low-voltage mode), higher-resolution observation or processing can be performed than when the first voltage V1 is applied to the extraction electrode 32 (high-voltage mode). Therefore, for example, during processing, a large volume of sample S can be efficiently processed with a large beam current in the high voltage mode, and if the resolution in the high voltage mode is insufficient for detailed observation of the sample S, the voltage applied to the extraction electrode 32 can be reduced from the first voltage V1 to the second voltage V2 and switched to the low voltage mode, thereby making it possible to observe with a higher resolution than during processing. Of course, it is also possible to finely process the sample S in the low voltage mode.

[0035] (2) The first voltage V1 is set so that the ion emission surface Ps has a concave shape, and the second voltage V2 is set so that the ion emission surface Ps has a convex shape. By storing such first voltage V1 and second voltage V2 in the storage device 60b, the control device 60 can change the extraction voltage in accordance with the magnitude of the beam current of the ion beam IB to be irradiated onto the sample S, thereby changing the shape of the ion emission surface Ps and switching the beam mode.

[0036] (3) When the applied voltage is set to the second voltage V2, the virtual light source L of the ion beam IB is farther away from the sample S than when the applied voltage is set to the first voltage V1. In this way, by switching the extraction voltage, the distance between the sample S and the light source can be changed, thereby controlling the effective optical magnification.

[0037] (4) Furthermore, the virtual light source L is smaller when the applied voltage is set to the second voltage V2 than when the applied voltage is set to the first voltage V1. As a result, the resolution is improved in the low voltage mode of FIG. 4 compared to the high voltage mode of FIG. 3.

[0038] (5) The charged particle beam device 1 is a composite charged particle beam device equipped with an electron beam column 40, and can process the sample S with an ion beam IB while observing the sample S with an electron beam, for example. However, the maximum resolution when using the ion beam IB in high-voltage mode is lower than the maximum resolution when using an electron beam with the electron beam column 40. In contrast, in this embodiment, by lowering the voltage applied to the extraction electrode 32 from the first voltage V1 to the second voltage V2 and switching to the low-voltage mode, it becomes possible to process the sample S more finely than in the high-voltage mode.

[0039] (6) Furthermore, the charged particle beam device 1 equipped with the electron beam tube 40 may process the sample S while observing it with the ion beam IB. In this case, if sputter generated during processing enters the inside of the electron beam tube 40, there is a possibility that the insulation of the electron beam tube 40 may deteriorate. In contrast, the charged particle beam device 1 of this embodiment is equipped with a shutter 41 that opens and closes the exit 42 of the electron beam tube 40, and therefore, it is possible to prevent sputter from entering the inside of the electron beam tube 40 and, ultimately, to prevent insulation deterioration of the electron beam tube 40.

[0040] -Modifications- The present invention is not limited to the above-described embodiments and may include various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. For example, it is possible to replace some of the configurations with other configurations. It is also possible to delete some of the configurations of the embodiments or add other configurations.

[0041] For example, in the above embodiment, an example has been described in which the invention is applied to a composite charged particle beam system having an electron beam column 40, but the invention can also be applied to an FIB system that does not have an electron beam column 40, and the same essential effects can be obtained. Also, an example has been described in which the invention is applied to a charged particle beam system having only one ion beam column 30, but the invention can also be applied to a charged particle beam system having multiple ion beam columns, and the same essential effects can be obtained. In this case, the ion beam column added in addition to the ion beam column 30 may use a plasma ion source or a liquid metal light source such as a gallium ion source.

[0042] 1...Charged particle beam device, 31...Plasma ion source, 31c...Orifice (opening of plasma ion source), 32...Extraction electrode, 33...Capacitor electrode, 34...Current limiting aperture, 35...Focus electrode, 40...Electron beam column, 41...Shutter, 42...Outlet, 60...Control device, IB...Ion beam, Is...Predetermined current, L...Virtual light source, Ps...Ion emission surface, S...Sample, V1...First voltage, V2...Second voltage

Claims

1. A charged particle beam device comprising a plasma ion source, an extraction electrode that forms an electric field for extracting ions from an opening of the plasma ion source, a current limiting aperture that narrows an ion beam extracted by the extraction electrode and adjusts a beam spot diameter formed on a sample and a beam current irradiated on the sample, and a control device that controls an applied voltage to the extraction electrode, wherein the control device stores a first voltage set for the applied voltage, a second voltage set lower than the first voltage, and a predetermined current set for the beam current of the ion beam, sets the applied voltage to the first voltage, drives the current limiting aperture to control the beam spot diameter, and varies the beam current within a range equal to or greater than the predetermined current, and in a range where the beam current is less than the predetermined current, sets the applied voltage to the second voltage and reduces the beam spot diameter compared to when the applied voltage is set to the first voltage.

2. The charged particle beam device according to claim 1, wherein the predetermined current corresponds to a beam current of an ion beam that reaches the sample when the first voltage is applied to the extraction electrode and the opening of the current limiting aperture is set to a minimum.

3. The charged particle beam device according to claim 1, further comprising a capacitor electrode that forms an electric field for collecting ions extracted by the extraction electrode, and a focus electrode that forms an electric field for focusing the ions on the sample, wherein the extraction electrode is disposed between the plasma ion source and the capacitor electrode.

4. The charged particle beam device according to claim 1, wherein the first voltage is set such that an ion emission surface at an opening of the plasma ion source has a concave shape, and the second voltage is set such that the ion emission surface has a convex shape.

5. The charged particle beam device according to claim 1, wherein a virtual light source of the ion beam is configured to be farther from the sample when the applied voltage is set to the second voltage than when the applied voltage is set to the first voltage.

6. In the charged particle beam device according to claim 5, the virtual light source is smaller when the applied voltage is set to the second voltage than when the applied voltage is set to the first voltage. A charged particle beam device characterized by this.

7. In the charged particle beam device according to claim 6, the virtual light source is a location where the ion orbits or their extension lines gather most densely. A charged particle beam device characterized by this.

8. In the charged particle beam device according to claim 1, it is characterized by comprising an electron beam column.

9. In the charged particle beam device according to claim 8, it is characterized by comprising a shutter for opening and closing the exit of the electron beam column.

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