Combined beam device

Abstract

A low-acceleration gas ion beam lens tube has a plasma ion source that produces gas ions and emits the same as an ion beam, a first focusing lens that is configured from an extraction electrode for the plasma ion source and a first lens electrode and focuses the ion beam emitted from the plasma ion source, a second focusing lens that focuses the ion beam which has passed through the first focusing lens, a blanker that changes the direction of progression of the ion beam which has passed through the second focusing lens, and switches between an irradiation condition in which a sample is irradiated with the ion beam and a blocked condition in which irradiation of the sample with the ion beam is blocked, and a scanning electrode that scans, across the sample, the ion beam which has passed through the blanker. The low-acceleration gas ion beam lens tube performs blanking control in which the blanker is used to switch to the blocked condition and a voltage that decelerates the ion beam emitted from the plasma ion source is applied to the first lens electrode. As a result, damage to a column inner wall or a diaphragm can be suppressed while radiation of the ion beam is continued.

Description

composite beam device

[0001] The present invention relates to a multiple beam device.

[0002] Techniques for analyzing the internal structure of a sample such as a semiconductor device or for three-dimensional observation include a sample cross-section processing and observation method using a composite beam device such as an FIB-SEM device equipped with a focused ion beam column that processes the cross section of the sample using an FIB (Focused Ion Beam), and an electron beam (EB) column that observes the cross section of the sample processed by the FIB using an SEM (Scanning Electron Microscope). Related techniques include those described in Patent Documents 1 and 2, for example.

[0003] Patent Document 1 discloses a charged particle beam device that includes at least a gallium ion beam column that irradiates a sample with a gallium ion beam to form a cross section of the sample, an electron beam column that has a semi-in-lens type objective lens and irradiates an electron beam toward the sample, and a gas ion beam column that irradiates the cross section of the sample with a gas ion beam to perform finishing processing of the cross section of the sample, wherein the gas ion beam has a beam diameter larger than the maximum diameter of the cross section of the sample.

[0004] Furthermore, Patent Document 2 discloses a charged particle beam system including: a focused ion beam source having an ion source, a source electrode that electrically biases the ion source to a high voltage, and an extraction electrode that extracts ions from the ion source; an ion column including one or more focusing lenses that focus charged particles from the focused ion beam source onto a sample; and a system controller that detects an idle state of the charged particle beam system, and, when the idle state is detected, changes the voltage applied to the source electrode and / or the extraction electrode to prevent ions from passing downward through the ion column.

[0005] JP 2019-145328 A JP 2013-214502 A

[0006] In the cross-section processing and observation of a sample, two layers are generated on the cross-section sample formed by cross-section forming processing: a damaged layer caused by FIB processing and a contaminated layer (a gallium (Ga) contaminant layer when a gallium ion beam is used). These two layers interfere with the surface observation of the sample cross-section using an SEM, so they are removed from the sample surface by irradiating it with a low-acceleration gas ion beam in the sample finishing process.

[0007] In the sample finishing process, for example, a low-acceleration gas ion beam column using a plasma ion source is mounted on the FIB-SEM device, and sample processing (finishing) is performed by irradiating the cross-sectional sample with a low-acceleration gas ion beam, thereby obtaining a high-quality cross-sectional sample that is free of FIB processing damage layers and gallium (Ga) contamination layers.

[0008] On the other hand, in processing steps other than the finishing step, irradiation of the cross-sectional sample with a gas ion beam is not necessary. However, if the emission of the gas ion beam from the plasma ion source (or an ion gun including the plasma ion source; hereinafter, simply referred to as an ion gun) is completely stopped when irradiating the cross-sectional sample with the gas ion beam, a long settling time is required for the gas ion beam emitted from the plasma ion source (or ion gun) to stabilize again. Therefore, a so-called blanking method is known in which, while continuing to emit the gas ion beam from the plasma ion source (or ion gun), the gas ion beam is bent and deflected by a deflector or the like in a low-acceleration gas ion beam column, thereby interrupting the irradiation of the gas ion beam on the sample.

[0009] However, during blanking, the gas ion beam continues to be emitted from the plasma ion source (or ion gun), causing the gas ion beam to continuously irradiate the inner wall and aperture of the low-acceleration gas ion beam column. This raises concerns about increased damage to the inner wall and aperture of the low-acceleration gas ion beam column due to the gas ion beam's radiation. Furthermore, the aperture installed at the exit of the ion gun is sputtered by the ion beam, and the particles generated during this process adhere to the ion source, further increasing damage to the ion source. One possible method to suppress this damage is to continue generating gas ions while preventing the gas ion beam from being emitted from the ion gun. Plasma ion sources include PIG (Penning Ionization Gauge) ion sources, duoplasmatrons, ICP (Inductively Coupled Plasma) ion sources, and ECR (Electron Cyclotron Resonance) ion sources. Sources other than the PIG ion source listed here have separate electromagnetic fields for generating plasma and extracting ions, so the number of emitted ions decreases if an extraction voltage is not applied. Plasma can diffuse through holes larger than the Debye length. Generally, plasma has a self-bias potential. This causes extraction electrodes and other components to be etched and damaged by the plasma, shortening their lifespan, so ion emission cannot be stopped. In the case of a PIG ion source, the voltage for plasma generation also serves as the ion extraction voltage, so ions are emitted while the plasma is being generated.

[0010] The present invention has been made in view of the above, and has an object to provide a composite beam device that can suppress damage to the inner wall of the column and the aperture while continuing to emit an ion beam from a plasma ion source.

[0011] The present application includes a plurality of means for solving the above-mentioned problems. One example thereof is a composite beam apparatus for performing sample cross-section processing and observation, which forms and observes a cross-section of a sample to be observed, the composite beam apparatus comprising: an ion beam column for irradiating the sample with a focused ion beam for processing; an electron beam column for irradiating an electron beam for observation of an electron microscope image of the cross-section of the sample processed by the focused ion beam; a low-acceleration gas ion beam column for irradiating a low-acceleration gas ion beam for finishing the cross-section of the sample; and a control device for controlling operations of the ion beam column, the electron beam column, and the low-acceleration gas ion beam column, the low-acceleration gas ion beam column comprising a plasma ion source for generating gas ions and emitting them as an ion beam, an extraction electrode of the plasma ion source, and a first lens electrode, and the low-acceleration gas ion beam column for irradiating a plasma ion source with a low-acceleration gas ion beam for finishing the cross-section of the sample. the control device is configured to switch between an ion beam irradiation control in which the blanker switches to the irradiation state and applies a predetermined voltage to the first lens electrode to accelerate the ion beam emitted from the plasma ion source, and a blanking control in which the blanker switches to the block state and applies a voltage to the first lens electrode to decelerate the ion beam emitted from the plasma ion source.

[0012] According to the present invention, damage to the inner wall of the column and the aperture can be suppressed while continuing the irradiation of the ion beam.

[0013] Fig. 1 is a diagram showing an outline of the overall configuration of a composite beam device according to the present embodiment; Fig. 2 is a diagram showing an extracted low-acceleration gas ion beam column; Fig. 3 is a diagram showing an extracted plasma ion source; Fig. 4 is a diagram showing an outline of a control device; Fig. 5 is a diagram showing applied voltages at each position on the path of a gas ion beam in a low-acceleration gas ion beam column, and a diagram showing the state during sample processing (finishing processing); Fig. 6 is a diagram showing applied voltages at each position on the path of a gas ion beam in a low-acceleration gas ion beam column, and a diagram showing the state when the beam is blocked (finishing processing is stopped);

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a low-acceleration gas ion beam column using a plasma ion source will be described as an example, but the present invention can also be applied to other column types that use charged particle beams, such as ion beam column and electron beam column.

[0015] FIG. 1 is a diagram showing a schematic overall configuration of a composite beam apparatus according to this embodiment.

[0016] In FIG. 1 , the composite beam device 100 performs sample cross-section processing and observation by forming and observing a cross-section of a sample 4 to be observed, and includes a focused ion beam column 2 that irradiates a focused ion beam (FIB) for processing the sample 4, an electron beam column 1 that constitutes a scanning electron microscope (SEM) that irradiates an electron beam (EB) for obtaining and observing an electron microscope image of the cross-section of the sample 4 processed by the focused ion beam, a low-acceleration gas ion beam column 3 that irradiates a low-acceleration gas ion beam 300 for finishing processing the cross-section of the sample 4, and a control device 5 that controls the operations of the focused ion beam column 2, the electron beam column 1, and the low-acceleration gas ion beam column 3.

[0017] The cross-sectional processing and observation of a sample in the composite beam device 100 is performed through the following steps: a cross-section forming processing step in which the sample 4 is processed by irradiating it with a focused ion beam from the focused ion beam column 2 to form a cross-sectional sample; a finishing step in which unnecessary layers are removed (finishing processing) from the surface (particularly the cross-section) of the sample 4 by irradiating it with a low-acceleration gas ion beam 300 from the low-acceleration gas ion beam column 3; and an observation step in which the surface of the sample 4 is observed by irradiating and scanning with an electron beam from the electron beam column 1.

[0018] The focused ion beam column 2 is equipped with a charged particle gun that uses a liquid metal ion source (LMIS) such as a gallium liquid metal ion source as a charged particle source, and two layers are generated on the cross-section sample formed by cross-section forming processing: a damaged layer caused by FIB processing and a gallium (Ga) contamination layer. Since these two layers interfere with surface observation of the sample cross-section using an SEM (observation process), a finishing process is performed in which the two layers (damaged layer and contamination layer) are removed from the surface of the sample 4 by irradiating it with a low-acceleration gas ion beam 300 from the low-acceleration gas ion beam column 3.

[0019] Fig. 2 is a schematic diagram showing the low-acceleration gas ion beam column of the composite beam device, and Fig. 3 is a schematic diagram showing the plasma ion source (gas ion gun) of the low-acceleration gas ion beam column.

[0020] 2 and 3 , the low-acceleration gas ion beam column 3 includes an ion gun 31 that generates gas ions to generate a low-acceleration gas ion beam 300, focuses the beam with a first focusing lens 32, and emits the beam; a second focusing lens 33 that focuses the low-acceleration gas ion beam 300 emitted from the ion gun 31; a blanker deflector 34 and a blanking aperture 341 that constitute a blanker that changes the direction of travel of the low-acceleration gas ion beam 300 that has passed through the second focusing lens 33 and has reached intermediate acceleration energy, thereby switching the irradiation mode (irradiation state and block state, which will be described later) on the sample 4; an intermediate acceleration tube 35 that changes the low-acceleration gas ion beam 300 that has passed through the blanker deflector 34 to intermediate acceleration energy; a beam limiting aperture 36 that limits the beam current of the low-acceleration gas ion beam 300; an objective lens 37 that focuses the low-acceleration gas ion beam 300 that has passed through the blanker; and a scanning electrode 38 that scans the low-acceleration gas ion beam 300 that has passed through the blanker and the objective lens 37 across the sample 4. A fixed aperture is installed at the entrance of each electrode to protect the electrode. Low acceleration refers to an acceleration potential of 5 kV or less.

[0021] The low-accelerated gas ion beam column 3 is also provided with a voltage signal source 35a that generates a voltage signal to be applied to the intermediate accelerating structure 35 relative to a reference potential (GND) (in other words, that adjusts the voltage applied to the intermediate accelerating structure 35), and a voltage signal source 34a that generates a voltage signal to be applied to the blanker deflector 34 relative to the potential of the intermediate accelerating structure 35 (in other words, that adjusts the voltage applied to the blanker deflector 34). The voltage signal sources 34a and 35a constitute a part of a voltage signal generating unit 3b (see FIG. 4 below) that generates voltage signals to be applied to the electrodes, etc. of the low-accelerated gas ion beam column 3.

[0022] 3 , the ion gun 31 is, for example, a PIG-type ion source, and a voltage is applied between an anode 311 and a cathode 312 to convert a gas supplied to the space between the anode 311 and the cathode 312 into plasma, with the cathode 312 functioning as an ion extraction electrode, causing ions in the converted gas to be emitted from a narrow gap provided in the cathode 312 toward a first lens electrode 313. Here, the cathode 312 and the first lens electrode 313, which function as extraction electrodes of the ion gun 31, form a first focusing lens 32 that focuses a low-acceleration gas ion beam 300 emitted from the ion gun 31. An aperture 314 is provided at the outlet (downstream side) of the first focusing lens 32 of the ion gun 31 to protect the second focusing lens 33 from the low-acceleration gas ion beam 300.

[0023] In this embodiment, a PIG type ion source is used as an example of the ion gun 31, but the present invention is not limited to this, and can also be applied to cases where other types of plasma ion sources, such as an ICP type ion source or an ECR type ion source, are used.

[0024] The low-acceleration gas ion beam column 3 has a bent portion 3a between the ion gun 31 and the scanning electrode 38. That is, the low-acceleration gas ion beam column 3 is formed in a cylindrical shape bent at the bent portion 3a so that the central axis differs between the upstream side and the downstream side of the bent portion 3a, and is formed by bending at the bent portion 3a so that the central axis on the downstream side of the bent portion 3a faces the direction of the sample 4 (here, this means the optical axis of the low-acceleration gas ion beam 300 irradiated onto the sample 4).

[0025] A blanker (blanker deflector 34 and blanking aperture 341) is arranged at the bending portion 3 a of the low-acceleration gas ion beam column 3, and by changing the traveling direction of the low-acceleration gas ion beam 300 that has passed through the second focusing lens 33 with the blanker, it is possible to switch between an irradiation state (see state A in Figure 2) in which the low-acceleration gas ion beam 300 is irradiated onto the sample 4 and a blocking state (see state B in Figure 2) in which the irradiation of the low-acceleration gas ion beam 300 onto the sample 4 is blocked.

[0026] When the blanker is switched to the irradiation state (see state A in Figure 2), the low-acceleration gas ion beam 300 emitted from the ion gun 31 passes through the second focusing lens 33 along the central axis on the upstream side of the bending section 3a of the low-acceleration gas ion beam column 3, is deflected in the bending section 3a by the blanker deflector 34 in a direction along the central axis on the downstream side, passes through the blanking aperture 341, the objective lens 37, etc., and is irradiated onto the sample 4.

[0027] In the ion gun 31, neutral particles are generated simultaneously with the gas ions, and are mixed into the low-acceleration gas ion beam 300 as a so-called neutral beam. On the other hand, since the neutral beam is not deflected by the blanker deflector 34, the neutral beam contained in the low-acceleration gas ion beam 300 travels straight along the central axis on the upstream side of the bending portion 3 a, whether the blanker is in the irradiation state or the blocking state, and is blocked by being irradiated by the blanking aperture 341. That is, the neutral beam contained in the low-acceleration gas ion beam 300 emitted from the ion gun 31 is separated and removed from the low-acceleration gas ion beam 300 irradiated onto the sample 4. When the neutral beam (neutral particles) is irradiated onto the sample 4, secondary electrons are generated on the surface of the sample 4, which interfere with SEM observation during finish processing of the sample 4 using the low-acceleration gas ion beam 300. However, in this embodiment, the neutral beam is separated and removed from the low-acceleration gas ion beam 300 irradiated onto the sample 4, enabling accurate SEM observation.

[0028] When the blanker is switched to the blocked state (see state B in Figure 2), the low-acceleration gas ion beam 300 emitted from the ion gun 31 passes through the second focusing lens 33 along the central axis on the upstream side of the bending section 3a of the low-acceleration gas ion beam column 3, passes through the blanker deflector 34 at the bending section 3a, travels straight in a direction along the central axis on the upstream side, and is blocked by the blanking aperture 341.

[0029] Fig. 4 is a schematic diagram illustrating a control system for a low-acceleration gas ion beam column of a composite beam instrument. Figs. 5 and 6 are schematic diagrams illustrating voltages (potentials of electrodes, etc.) applied to voltages, etc., at various positions on the path of the low-acceleration gas ion beam, with Fig. 5 illustrating the state during sample processing (finishing processing) and Fig. 6 illustrating the state when the beam is blocked (finishing processing is stopped). In Figs. 5 and 6, the horizontal axis represents the position of the electrodes, etc. on the path of the low-acceleration gas ion beam, and the vertical axis represents the potential (applied voltage) of the electrodes, etc., relative to the potential of the sample 4 (sample stage) (reference potential: GND).

[0030] As shown in Fig. 4, the control system for the low-acceleration gas ion beam column 3 includes a control device 5 and a voltage signal generator 3b that generates voltage signals to be applied to the electrodes of the low-acceleration gas ion beam column 3 based on control signals from the control device 5. In Fig. 4, of the multiple voltage signals generated by the voltage signal generator 3b and applied to the electrodes of the low-acceleration gas ion beam column 3, a voltage signal (V ３４ ), and a voltage signal (V ３２ ) are shown as representative examples.

[0031] When a control signal for finish machining (sample machining) is input from the control device 5, the voltage signal generating unit 3b outputs a voltage signal V ３２ =A1 [V] is applied to the blanker deflector 34, and a voltage signal V ３４ = A2 [V] is applied. Here, the voltage signal V ３２ = A1 [V] is the acceleration voltage (V ３１１ = 0.1 [kV] to 5.0 [kV]) as a reference, and is, for example, a voltage signal of about -0.1 [kV] to -2.0 [kV]. ３４=A2 [V] is based on the voltage applied to the intermediate accelerating tube 35, and is a voltage signal that deflects the low-acceleration gas ion beam 300 that has been incident on the blanker deflector 34 from the upstream side of the bending portion 3a in a direction that causes the beam to be incident on the objective lens 37 on the downstream side of the bending portion 3a and irradiate the sample 4. Therefore, the voltage signal V ３４ is determined using the acceleration voltage and the intermediate acceleration voltage as variables, and the set values ​​are stored in a control device or the like, and can be called up at any time and easily output from the voltage signal generating unit 3b. ３４ When the voltage A2 [V] is applied, the low-acceleration gas ion beam 300 is bent at the bending portion 3a and irradiated onto the sample 4 (irradiation state), thereby performing finish processing.

[0032] As shown in FIG. 5, the potential of each electrode during sample processing (finish processing) is the acceleration voltage V applied to the anode 311. ３１１ indicates the energy of the low-acceleration gas ion beam 300 irradiated onto the sample 4 placed on the sample stage. The cathode 312 (ion extraction electrode) is applied with an acceleration voltage V ３１１ With reference to the voltage signal V ３１２ Similarly, an acceleration voltage V ３１１ With reference to the voltage signal V ３２ Furthermore, a voltage signal V = A1 [V] is applied to the second focusing lens 33 with respect to the reference potential (GND). ３３ However, the intermediate accelerating tube 35 receives a voltage signal V ３５ However, the objective lens 37 receives a voltage signal V ３７ are applied, respectively.

[0033] During sample processing (finish processing), a low-acceleration gas ion beam 300 generated by the ion gun 31 is accelerated by a cathode 312 (extraction electrode), and is then accelerated and focused by a first focusing lens 32. The low-acceleration gas ion beam 300 that has passed through a first lens electrode 313 of the first focusing lens 32 is partially restricted by an aperture 314, and is then decelerated and focused by a second focusing lens 33, accelerated by an intermediate accelerating tube 35, and decelerated and focused by an objective lens 37, before being irradiated onto a sample 4.

[0034] Furthermore, when a control signal for stopping the finishing process (when the beam is interrupted) is input from the control device 5, the voltage signal generating unit 3b applies a voltage signal V ３２ =0 [V] is applied to the blanker deflector 34, and a voltage signal V ３４ = 0 [V]. Voltage signal V ３２ = 0 [V] is the acceleration voltage (V ３１１ = 0.1 [kV] to 5.0 [kV]) as a reference, and the potential of the first lens electrode 313 at this time is the acceleration voltage (V ３１１ ) Also, the voltage signal V ３４ =0 [V] is based on the voltage applied to the intermediate accelerating tube 35, and is a voltage signal that causes the low-accelerated gas ion beam 300, which has been incident on the blanker deflector 34 from the upstream side of the bending portion 3 a, to travel straight without deflection and to be irradiated onto the blanking aperture 341 on the downstream side of the bending portion 3 a. At this time, irradiation of the low-accelerated gas ion beam 300 onto the sample 4 is blocked (blocked state), and the finishing process is stopped.

[0035] As shown in FIG. 6, the potential of each electrode when sample processing is stopped (when finish processing is stopped) is the acceleration voltage V applied to the anode 311. ３１１ indicates the energy of the low-acceleration gas ion beam 300 irradiated onto the sample 4 placed on the sample stage. The cathode 312 (ion extraction electrode) is applied with an acceleration voltage V ３１１ With reference to the voltage signal V ３１２ Similarly, an acceleration voltage V ３１１ With reference to the voltage signal V ３２ = 0 [V] is applied to the second focusing lens 33. ３３ However, the intermediate accelerating tube 35 receives a voltage signal V ３５ However, the objective lens 37 receives a voltage signal V ３７ are applied, respectively.

[0036] When sample processing is stopped (finish processing is stopped), the low-acceleration gas ion beam 300 generated by the ion gun 31 is accelerated by the cathode 312 (extraction electrode) and decelerated by the first focusing lens 32. The low-acceleration gas ion beam 300 that passes through the first lens electrode 313 of the first focusing lens 32 is partially restricted by the aperture 314, passes through the second focusing lens 33 and the blanker deflector 34, and is blocked by the blanker aperture 341. At this time, the energy of the low-acceleration gas ion beam 300 becomes almost zero at the first lens electrode 313, thereby reducing the sputtering capability. Furthermore, since the low-acceleration gas ion beam 300 that passes through the first focusing lens 32 has almost zero energy, it spreads on the aperture 314 and reduces the current density. That is, the low-acceleration gas ion beam that passes through the aperture 314 has low energy and a low current density, which can prevent damage to the aperture.

[0037] The effects of the present embodiment configured as above will be described.

[0038] In the cross-section processing and observation of a sample, two layers are generated on the cross-section sample formed by cross-section forming processing: a damaged layer caused by FIB processing and a contaminated layer (a gallium (Ga) contaminant layer when a gallium ion beam is used). These two layers interfere with the surface observation of the sample cross-section using an SEM, so they are removed from the sample surface by irradiating it with a low-acceleration gas ion beam in the sample finishing process.

[0039] In the sample finishing process, for example, a low-acceleration gas ion beam column using a plasma ion source is mounted on the FIB-SEM device, and sample processing (finishing) is performed by irradiating the cross-sectional sample with a low-acceleration gas ion beam, thereby obtaining a high-quality cross-sectional sample that is free of FIB processing damage layers and gallium (Ga) contamination layers.

[0040] On the other hand, in processing steps other than the finishing step, irradiation of the cross-sectional sample with a gas ion beam is not necessary. However, if the emission of the gas ion beam from the plasma ion source (or an ion gun including the plasma ion source; hereinafter, simply referred to as the ion gun) is completely stopped when irradiating the cross-sectional sample with the gas ion beam, a long settling time is required for the gas ion beam emitted from the plasma ion source (or ion gun) to stabilize again. Therefore, in this embodiment, while continuing to emit the low-acceleration gas ion beam 300 from the ion gun 31, the blanker deflector 34 in the low-acceleration gas ion beam column 3 deflects the low-acceleration gas ion beam 300 to deviate from the irradiation direction, thereby blocking the irradiation of the low-acceleration gas ion beam 300 onto the sample 4, i.e., performing so-called blanking. This allows the irradiation of the low-acceleration gas ion beam 300 onto the sample 4 to be blocked while continuing to emit the ion beam from the plasma ion source.

[0041] In addition, the low-acceleration gas ion beam column 3 has a bending portion 3a between the ion gun 31 and the scanning electrode 38, and is configured to have a blanker (blanker deflector 34 and blanking aperture 341) disposed at the bending portion 3a, so that the low-acceleration gas ion beam 300 is deflected by the blanker toward the sample 4 when irradiating the sample 4, thereby making it possible to remove neutral beams (neutral particles) contained in the low-acceleration gas ion beam 300 irradiated onto the sample 4.

[0042] Furthermore, in a state where the irradiation of the low-acceleration gas ion beam 300 onto the sample 4 is cut off, the first focusing lens 32 functions as a deceleration lens while continuing to emit the low-acceleration gas ion beam 300 from the ion gun 31, thereby suppressing the energy of the low-acceleration gas ion beam 300 at the first lens electrode 313 and the aperture 314 to almost zero, thereby suppressing damage to the column inner wall and aperture of the low-acceleration gas ion beam column 3 caused by the low-acceleration gas ion beam 300. Furthermore, if there is a current leaking downstream of the blanker deflector, this current can be reduced, thereby reducing background noise in the SEM image.

[0043] That is, in this embodiment, it is possible to suppress damage to the inner wall of the column and the aperture while continuing to emit an ion beam from the plasma ion source.

[0044] <Notes> The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist thereof. Furthermore, the present invention is not limited to those including all of the configurations described in the above-described embodiments, and also includes those in which some of the configurations are omitted. Furthermore, the above-described configurations, functions, etc. may be realized in part or in whole by designing them as, for example, integrated circuits. Furthermore, the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function.

[0045] 1...electron beam column, 2...focused ion beam column, 3...low-acceleration gas ion beam column, 3a...bending portion, 3b...voltage signal generating portion, 4...sample, 5...control device, 31...ion gun (plasma ion source), 32...first focusing lens, 33...second focusing lens, 34...blanker deflector, 34a...voltage signal source, 35...intermediate acceleration tube, 35a...voltage signal source, 37...objective lens, 38...scanning electrode, 100...composite beam device, 300...low-acceleration gas ion beam, 311...anode, 312...cathode, 313...first lens electrode

Claims

1. A composite beam apparatus for processing and observing a cross section of a sample to be observed, which forms and observes a cross section of the sample, the composite beam apparatus comprising: an ion beam column that irradiates the sample with a focused ion beam for processing the sample; an electron beam column that irradiates an electron beam for observation using an electron microscope image of the cross section of the sample processed by the focused ion beam; a low-acceleration gas ion beam column that irradiates a low-acceleration gas ion beam for finishing the cross section of the sample; and a control device that controls the operations of the ion beam column, the electron beam column, and the low-acceleration gas ion beam column, wherein the low-acceleration gas ion beam column comprises: a plasma ion source that generates gas ions and emits them as an ion beam; a first focusing lens that is composed of an extraction electrode and a first lens electrode of the plasma ion source and that focuses the ion beam emitted from the plasma ion source; and a second focusing lens that focuses the ion beam that has passed through the first focusing lens. a blanker that changes the traveling direction of the ion beam that has passed through the second focusing lens to switch between an irradiation state in which the ion beam is irradiated onto the sample and a blocking state in which irradiation of the ion beam onto the sample is blocked, and a scanning electrode that scans the sample with the ion beam that has passed through the blanker, wherein the control device switches between an ion beam irradiation control that uses the blanker to switch to the irradiation state and applies to the first lens electrode a predetermined voltage that accelerates the ion beam emitted from the plasma ion source, and a blanking control that uses the blanker to switch to the blocking state and applies to the first lens electrode a voltage that decelerates the ion beam emitted from the plasma ion source.

2. A composite beam device according to claim 1, wherein the control device applies to the first lens electrode, during the blanking control, a voltage that is smaller than the acceleration voltage applied to the ion beam by the plasma ion source and that decelerates the ion beam.

3. A composite beam device according to claim 1, characterized in that the control device applies to the first lens electrode a voltage equal to the acceleration voltage applied to the ion beam by the plasma ion source during the blanking control.

4. A composite beam device according to claim 1, characterized in that the control device applies to the first lens electrode, during the blanking control, a voltage that reduces the kinetic energy of the ion beam emitted from the plasma ion source.

5. A composite beam device according to claim 1, wherein the control device applies to the first lens electrode a voltage that makes the kinetic energy of the ion beam emitted from the plasma ion source zero during the blanking control.

6. A composite beam device according to claim 1, wherein the low-acceleration gas ion beam column has a bent portion between the plasma ion source and the scanning electrode, and the blanker has a blanker deflector and a blanking aperture disposed at the bent portion.

7. A composite beam device according to claim 1, characterized in that the plasma ion source is a plasma ion source that applies a voltage to an anode and a cathode to generate plasma in the space between the anode and the cathode.

Images