Cluster Ion Beam Equipment

Abstract

To provide a focused ion beam device capable of shortening a tact time required for processing a substrate to be processed without damaging the substrate itself during ion beam adjustment.SOLUTION: A focused ion beam device includes a beam emission unit having a focused ion beam optical system that adjusts and emits an ion beam extracted from an ion source into an internal space, an opening that communicates with the internal space and allows the ion beam emitted from the beam emission unit to pass therethrough such that the substrate to be processed can be irradiated with the beam, and the interior space is evacuated, and the focused ion beam device further includes a movable sealing valve capable of opening and closing the opening.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a focused ion beam apparatus.

Background Art

[0002] A charged particle beam lithography apparatus is known (see, for example, Patent Document 1). This charged particle beam lithography apparatus includes a beam irradiation device and a vacuum envelope device. The beam irradiation device has an internal space maintained in a high vacuum state and a tip opening provided at the tip on the beam emission side. The vacuum envelope device is provided so as to surround the tip opening of the beam irradiation device and has a function of locally evacuating the space near the tip opening. By approaching the surface to be processed (the surface) of the semiconductor wafer and making the gap between the surface to be processed extremely small, the space between the tip of the beam irradiation device and the surface to be processed can be maintained in a high vacuum state.

[0003] In this charged particle beam lithography apparatus, in order to perform various adjustments on the position and shape of the charged particle beam, the following detection operations are necessary. That is, the charged particle beam emitted through the above-described tip opening is irradiated onto a reference mark formed on an alignment pad disposed around the semiconductor wafer. Then, based on the information obtained due to the irradiation of the charged particle beam onto this reference mark, adjustments such as the position and shape of the charged particle beam are performed in the beam irradiation device. The reason for performing the detection operation using the reference mark formed on the alignment pad is that the semiconductor wafer is damaged when the semiconductor wafer is directly irradiated with the charged particle beam. Such a detection operation is performed each time the semiconductor wafer is replaced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described charged particle beam lithography apparatus, every time adjustments such as the position of the charged particle beam and the shape of the beam are made, it is necessary to relatively move the charged particle beam lithography apparatus so that it is disposed above the reference mark of the alignment pad. Therefore, there is a problem that the tact time in the processing of the semiconductor wafer becomes long.

[0006] In addition, in the above-described charged particle beam lithography apparatus, when the vacuum envelope apparatus moves away from the surface to be processed of the semiconductor wafer, there is a problem that the space between the tip of the beam irradiation apparatus and the surface to be processed cannot be maintained in a high-vacuum state. Generally, while the charged particle beam lithography apparatus is moved away from the semiconductor wafer to the standby position, the semiconductor wafer is replaced. For this reason, every time the semiconductor wafer is replaced, the inside of the beam irradiation apparatus temporarily becomes a low-vacuum state. Therefore, after replacing the semiconductor wafer with the next one, the charged particle beam lithography apparatus is brought close to the semiconductor wafer, and the internal space of the beam irradiation apparatus is adjusted to be in a high-vacuum state with the vacuum envelope apparatus operating. For this reason, time for moving the charged particle beam lithography apparatus and adjusting the pressure is required. Therefore, in such a charged particle beam lithography apparatus, there is a problem that the tact time in the processing of the semiconductor wafer becomes long.

[0007] The present invention has been made in view of the above problems, and an object thereof is to provide a focused ion beam apparatus capable of shortening the tact time without damaging the substrate to be processed itself during ion beam adjustment.

Means for Solving the Problems

[0008] In order to solve the above-described problems and achieve the object, an aspect of the present invention is a beam emitting unit including a focused ion beam optical system that adjusts and emits an ion beam drawn from an ion source into an internal space, and an opening that communicates with the internal space and allows the ion beam emitted from the beam emitting unit to pass through to enable beam irradiation of a substrate to be processed. The focused ion beam apparatus is characterized in that the internal space is evacuated and includes a movable sealing valve that can open and close the opening.

[0009] As the above aspect, it is preferable that a secondary charged particle detector for detecting secondary charged particles is provided in the internal space, and an adjustment reference pattern is arranged at a position where the ion beam is irradiated when the opening is closed in the movable sealing valve.

[0010] As the above aspect, it is preferable that a galvanometer is connected to the adjustment reference pattern.

[0011] As the above aspect, it is preferable that the beam emitting unit includes a focused ion beam column incorporating the focused ion beam optical system and a head unit including a differential evacuation unit disposed at an end on the emission side of the focused ion beam column.

[0012] As the above aspect, it is preferable that the internal space is a communicating space formed in the focused ion beam column and the head unit, and the opening is formed in the head unit.

[0013] As the above aspect, it is preferable that the internal space is a space formed inside the focused ion beam column, and the opening is formed at an end on the emission side of the focused ion beam column.

[0014] As the above aspect, it is preferable that the movable sealing valve is reciprocally driven between a position where the opening is closed and a standby position where the ion beam in the internal space is not irradiated.

[0015] As the above aspect, it is preferable that the adjustment reference pattern is a metal mesh.

[0016] As the above aspect, it is preferable that the ammeter is a picoammeter.

Effect of the Invention

[0017] According to the focused ion beam apparatus of the present invention, there is an effect of shortening the tact time required for processing a substrate to be processed using a focused ion beam.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0019] The details of the focused ion beam apparatus according to the embodiment of the present invention will be described below with reference to the drawings. However, it should be noted that the drawings are schematic, and the number of each member, the dimensions of each member, the ratio of the dimensions, the shape, etc. are different from the actual ones. Also, there are portions where the relationship, ratio, and shape of the dimensions of each other are different among the drawings.

[0020] [First Embodiment] (Configuration of Focused Ion Beam Apparatus) The focused ion beam apparatus according to the first embodiment of the present invention can be used, for example, as a photomask correction apparatus used in the manufacture of flat panel displays (FPDs) such as liquid crystal displays (LCDs: Liquid Crystal Display) and organic EL displays (OLEDs: Organic Electroluminescence Display).

[0021] As shown in FIG. 1, the focused ion beam apparatus 1 according to the present embodiment includes a substrate support base 2, a focused ion beam column 3, a head unit 4, a differential evacuation unit 5, a secondary charged particle detector 6, a movable seal valve 7, an ammeter 8, a valve drive unit 9, and a control unit 10. The focused ion beam column 3 and the head unit 4 constitute a beam emission unit 11.

[0022] The substrate support base 2 is configured to support the substrate to be processed 12 in a placed state. In the present embodiment, a large photomask is applied as the substrate to be processed 12. The substrate support base 2 is relatively movable in the X - Y direction with respect to the beam emission unit 11. The substrate support base 2 may also be relatively movable in the Z direction with respect to the beam emission unit 11.

[0023] (Focused Ion Beam Column) The focused ion beam column 3 includes an optical column 13. Inside the optical column internal space 13A within the optical column 13, a liquid metal ion source 14 and a focused ion beam optical system 15 are incorporated. Note that a vacuum pump (e.g., an ion pump, etc.) (not shown) is connected to the upper part of the optical column 13 via a connection pipe 13B. At the tip (lower end) of the optical column 13, an optical column tip opening 13C through which the ion beam IB can pass is formed.

[0024] The liquid metal ion source 14 includes, for example, gallium (Ga) which is a liquid metal. In the liquid metal ion source 14, the liquid metal is ionized by field emission, and gallium ions (Ga + ) are emitted from the tip.

[0025] The focused ion beam optical system 15 includes a condenser lens 16, an aperture 17, an astigmatism correction stigmator 18, a blanker 19, a blanking aperture 20, a deflector 21, and an object lens 22. In the present embodiment, the condenser lens 16, the astigmatism correction stigmator 18, the blanker 19, the deflector 21, and the object lens 22 are controlled based on control signals from the control unit 10.

[0026] The condenser lens 16 is an electrostatic lens. The gallium ions (Ga + ) emitted from the liquid metal ion source 14 are accelerated by an acceleration voltage (partially an ion overvoltage) by the extraction electrode (not shown) on the most upstream side in the condenser lens 16 to become the ion beam IB.

[0027] The astigmatism correction stigmator 18 is composed of, for example, eight dipole electrodes (not shown). In this astigmatism correction stigmator 18, based on the control signal from the control unit 10, by changing the magnitude of the voltage values of the eight dipole electrodes, the axial shift amount and the beam shape of the ion beam IB can be changed.

[0028] Based on the control signal from the control unit 10, the blanker 19 has the function of guiding the ion beam IB to the light-shielding part (the area where no opening is formed) of the blanking aperture 20 by applying a blanking voltage, so as to deflect the ion beam IB and prevent the ion beam IB from heading towards the substrate 12 to be processed.

[0029] The deflector 21 can deflect the ion beam IB and scan it in the X-Y directions. The object lens 22 is an electrostatic lens and has the function of focusing the ion beam IB onto the surface of the substrate 12 to be processed based on the control signal from the control unit 10.

[0030] (Head part) As shown in FIG. 1, the head part 4 is a substantially disk-shaped hollow body arranged such that its central axis coincides with the central axis of the lens barrel 13. The head part 4 is composed of an upper main body 41 having a disk shape like the upper part of a cone cut off, a lower main body 42 having a disk shape, and a groove-forming plate 43, and a head internal space 4A is formed inside. This head internal space 4A communicates with the lens barrel internal space 13A inside the lens barrel 13 of the focused ion beam column 3 described above and constitutes the internal space of the beam emission part 11. This internal space is evacuated to a predetermined degree of vacuum by a vacuum pump (not shown) connected via a connection pipe 13B at the upper part of the lens barrel 13.

[0031] A column coupling port 41A in the shape of a cylindrical hole penetrating in the rotation axis direction is formed at the center of the upper main body 41. The lower main body 42 has a lower main body opening 42A formed at its center. A head part tip opening 43A is formed at the center of the groove-forming plate 43. This head part tip opening 43A is an opening that allows the ion beam IB to pass through and enables beam irradiation onto the substrate 12 to be processed. The tip part of the focused ion beam column 3 is coupled to the column coupling port 41A in a penetrating state. A differential exhaust part 5 is provided on the lower surface of the lower main body 42 so as to surround the head part tip opening 43A.

[0032] (Differential exhaust part) The differential exhaust section 5 is composed of the lower main body 42 and the groove forming plate 43. On the lower surface 43B of the groove forming plate 43, for example, three annular grooves 44, 45, 46 are formed concentrically at a predetermined distance in the radial direction so as to surround the head portion tip opening 43A. Further, on the lower surface of the lower main body 42, communication grooves 47, 48, 49, 50 that communicate with these annular grooves 44, 45, 46 as appropriate are formed. These communication grooves 47, 48, 49, 50 are connected to a vacuum pump (not shown) via a path (not shown).

[0033] In the present embodiment, the suction and exhaust performance in the annular grooves 44, 45, 46 is set to gradually increase from the outer annular groove 46 toward the inner annular groove 44 so as to perform differential exhaust. That is, in the annular grooves 44, 45, 46, it is set to gradually become a lower pressure from the outermost annular groove 46 toward the innermost annular groove 44.

[0034] (Secondary charged particle detector) The head portion 4 is provided with a secondary charged particle detector 6. The tip side of this secondary charged particle detector 6 is disposed in the head internal space 4A. This secondary charged particle detector 6 is connected to the control unit 10 and is configured to output the detected information to the control unit 10.

[0035] In the present embodiment, the secondary charged particle detector 6 is composed of a scintillator. The tip portion of the secondary charged particle detector 6 is disposed so as to face the head portion tip opening 43A from the side so that the ion beam IB does not directly hit it. Note that a photomultiplier (not shown) that amplifies the light generated by the secondary charged particle detector 6 is connected to the secondary charged particle detector 6.

[0036] The secondary charged particle detector 6 is configured to capture secondary charged particles emitted when a metal mesh 74, which serves as an adjustment reference pattern provided in a movable sealing valve 7 described later, is irradiated with an ion beam IB, and to acquire surface information of the metal mesh 74. Based on the surface information of the metal mesh 74 obtained from this secondary charged particle detector 6, it is possible to adjust the position of the ion beam IB and various beam parameters.

[0037] (Movable Sealing Valve) As shown in FIGS. 1 and 2, the movable sealing valve 7 has a function of opening and closing the head tip opening 43A from the inside of the head portion 4. As shown in FIGS. 1 to 3, the movable sealing valve 7 includes a rod portion 71, a valve body 72, a vacuum pad 73, and a metal mesh (adjustment reference pattern) 74.

[0038] The rod portion 71 penetrates the head portion 4 and is provided so as to be reciprocally movable along the axial direction while maintaining the degree of vacuum in the head internal space 4A. The rod portion 71 is driven by a valve drive portion 9 provided outside the head portion 4. The valve drive portion 9 drives the rod portion 71 based on a control signal from the control portion 10. In this embodiment, for example, an air actuator is used as the valve drive portion 9.

[0039] As shown in FIG. 3, the valve body 72 is provided at the tip of the rod portion 71. A vacuum pad 73 is provided on the lower surface of the valve body 72. The vacuum pad 73 is formed of, for example, a fluororesin. As the rod portion 71 moves, the vacuum pad 73 moves between a position where it releases the head tip opening 43A shown in FIG. 1 and does not interfere with the ion beam IB (standby position) and a position where it closes the head tip opening 43A shown in FIG. 2.

[0040] The metal mesh 74 moves between a position (standby position) where it does not interfere with the ion beam IB shown in FIG. 1 and a position where the ion beam IB is irradiated as shown in FIG. 2 as the rod portion 71 moves. As shown in FIG. 4, the metal mesh 74 is composed of a circular frame body 74A and a circular metal mesh body 74B fixed to this frame body 74A. The metal mesh 74 may be detachably supported with respect to the valve body 72. The valve body 72 may be detachably supported with respect to the rod portion 71. As the metal mesh body 74B, for example, metals such as molybdenum (Mo), tin (Sn), and gold (Au) can be selected.

[0041] As described above, in this focused ion beam apparatus 1, the metal mesh 74 emits secondary charged particles when irradiated with the ion beam IB, and the secondary charged particle detector 6 captures the secondary charged particles. When surface information of the metal mesh 74 is supplied from the secondary charged particle detector 6 to the control unit 10, the irradiation position of the ion beam IB and various adjustments of the beam can be performed.

[0042] In the present embodiment, an ammeter 8 is connected to the metal mesh 74 of the movable seal valve 7 via the rod portion 71. In the present embodiment, this ammeter 8 is a picoammeter that measures a minute direct current. This movable seal valve 7 can detect the current value of the ion beam IB by the ammeter 8. Therefore, the control unit 10 can adjust the beam current of the ion beam IB based on the detected current value by the ammeter 8.

[0043] (Operation and movement of the focused ion beam apparatus) As shown in FIG. 1, when using the focused ion beam apparatus 1 to irradiate the substrate 12 to be processed with the ion beam IB to perform a process such as correcting a mask pattern, etc., in advance, differential evacuation is performed while maintaining a predetermined narrow gap between the lower surface of the groove forming plate 43 constituting the differential evacuation unit 5 and the substrate 12 to be processed.

[0044] At this time, the internal space composed of the internal space 13A of the lens barrel and the internal space 4A of the head is in a state of being evacuated to a predetermined degree of vacuum by a vacuum pump (not shown) connected via a connecting pipe 13B at the upper part of the lens barrel 13.

[0045] As shown in FIG. 1, the movable sealing valve 7 places the valve body 72 in a standby position where it does not interfere with the ion beam IB. That is, since the vacuum pad 73 and the metal mesh 74 are arranged in the standby position, the tip opening 43A of the head portion is in an open state, and the metal mesh 74 is not irradiated with the ion beam IB.

[0046] In such a state, an ion beam IB is generated from the focused ion beam column 3, and the ion beam IB is irradiated onto the substrate 12 to be processed to perform processes such as correction.

[0047] Next, in the focused ion beam apparatus 1, when performing various adjustments of the position and beam of the ion beam IB, as shown in FIG. 2, the movable sealing valve 7 is operated so that the vacuum pad 73 closes the tip opening 42A of the head portion. At this time, since the internal space (the internal space 13A of the lens barrel and the internal space 4A of the head) is blocked from the outside space by the movable sealing valve 7, the internal pressure is maintained.

[0048] Next, as shown in FIG. 2, the ion beam IB is raster scanned onto the metal mesh 74 of the movable sealing valve 7. Secondary charged particles are generated with such irradiation of the ion beam IB. The secondary charged particle detector 6 captures these secondary charged particles and outputs a detection signal to the control unit 10. By mapping the irradiation position of the ion beam IB and the detection signal, it becomes possible to observe the SIM (Scanning Ion Microscope) image of the metal mesh 74. While observing this SIM image, it becomes possible to perform various adjustments such as position adjustment, output adjustment, focus adjustment, axis adjustment, and aberration correction of the ion beam IB, and the ion beam IB can be brought into an optimal state.

[0049] As described above, after various adjustments of the ion beam IB, the lens voltage of the objective lens 22 may be adjusted so that the ion beam IB is focused on the position of the surface of the substrate 12 to be processed that is separated from the position of the metal mesh 74 by a predetermined design value. Therefore, the substrate 12 to be processed can be processed immediately without actually performing focus adjustment on the surface of the substrate 12. The beam current can be measured simultaneously by the ammeter 8 connected to the movable seal valve 7, and thereby the control unit 10 can adjust the beam current of the ion beam IB.

[0050] (Effect of the First Embodiment) When performing correction processing on a photomask as the substrate 12 to be processed using the focused ion beam apparatus 1, it is necessary to adjust the position of the ion beam IB and various beam adjustments during the work. Regardless of the size of the photomask, in order to perform accurate correction work, it is required to always keep the state of the ion beam IB appropriate. In the focused ion beam apparatus 1 according to the present embodiment, even during the correction work, the adjustment work of the ion beam IB can be quickly performed without breaking the vacuum in the internal space (the lens barrel internal space 13A and the head internal space 4A). Therefore, in the processing of the substrate 12 to be processed, the tact time can be significantly shortened.

[0051] In addition, since the vacuum in the internal space (the lens barrel internal space 13A and the head internal space 4A) is not broken every time the adjustment work of the ion beam IB is performed as described above, the burden on a vacuum pump (not shown) connected to the connection pipe 13B can be significantly reduced.

[0052] In the focused ion beam apparatus 1 according to the present embodiment, by providing the movable seal valve 7 in the head internal space 4A where the secondary charged particle detector 6 is disposed, the opening and closing of the tip opening 43A of the head portion can be efficiently performed without affecting the positional relationship between the beam emission portion 11 and the substrate 12 to be processed.

[0053] In the focused ion beam apparatus 1 according to the present embodiment, when the movable seal valve 7 is closed, the metal mesh 74 is automatically set to be disposed at a position where it can be irradiated with the ion beam IB, so that the ion beam IB can be adjusted immediately.

[0054] In the focused ion beam apparatus 1 according to the present embodiment, when detecting secondary charged particles, irradiation of the ion beam IB onto the substrate 12 to be processed can be avoided, so that damage to the substrate 12 to be processed by the ion beam IB can be prevented.

[0055] Incidentally, conventionally, adjustment operations such as orbit adjustment (alignment), focus adjustment, and aberration correction of the ion beam IB were performed while irradiating the ion beam IB onto the substrate 12 to be processed and detecting secondary charged particles generated from the substrate 12 to be processed.

[0056] As the liquid metal ion source 14, by using an ion beam IB of gallium having a large mass number, the sputtering processing rate can be increased, but there was a problem that the irradiated photomask was always processed.

[0057] That is, when the focused ion beam apparatus is used for photomask correction work, if the adjustment work takes a long time, there was a problem that peripheral portions that do not require correction other than the defective portion (region to be corrected) are also processed. In the above-described focused ion beam apparatus 1, since the substrate 12 to be processed is not used for the adjustment work of the ion beam IB, the substrate 12 to be processed is not damaged.

[0058] [Second Embodiment] FIGS. 5 and 6 show a focused ion beam apparatus 1A according to the second embodiment of the present invention. In the description of the focused ion beam apparatus 1A according to the present embodiment, parts different from the configuration of the first embodiment will be described, and descriptions of the same configurations will be omitted.

[0059] In this focused ion beam apparatus 1A, the internal space 13A of the lens barrel 13 that constitutes the focused ion beam column 3 corresponds to the internal space of the present invention. Further, the lens barrel tip opening 13C corresponds to the opening that is opened and closed in the present invention. In the present embodiment, the portion corresponding to the head portion 4 in the first embodiment is composed of a head plate 51 and a groove forming plate 43. The differential evacuation portion 5 is configured using the head plate 51 and the groove forming plate 43.

[0060] In the present embodiment, the secondary charged particle detector 6 and the movable seal valve 7 are disposed at the lower part of the internal space 13A of the lens barrel 13. The vacuum pad 73 of the movable seal valve 7 is set to open and close the lens barrel tip opening 13C. Other configurations of the focused ion beam apparatus 1A according to the present embodiment are the same as those of the focused ion beam apparatus 1 according to the first embodiment.

[0061] The focused ion beam apparatus 1A according to the present embodiment exhibits the same effects as the focused ion beam apparatus 1 according to the first embodiment. In addition, in the focused ion beam apparatus 1A according to the present embodiment, by disposing the secondary charged particle detector 6 and the movable seal valve 7 in the internal space 13A of the lens barrel, the apparatus has been made more compact and lighter.

[0062] [Other Embodiments] As described above, the embodiments of the present invention have been described. However, it should not be understood that the descriptions and drawings that form part of the disclosure of the embodiments limit the present invention. Various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art from this disclosure.

[0063] In the above embodiment, a photomask is applied as the substrate 12 to be processed. However, the present invention is not limited to this, and various samples on which processing by the ion beam IB is performed can be applied, and it is not limited to the use of correction.

[0064] In the above embodiment, an air actuator is used as the valve drive unit 9. However, the present invention is not limited to this, and other actuators can also be applied.

[0065] In the above embodiment, the metal mesh 74 is used as the adjustment reference pattern, but the present invention is not limited to this, and patterns of various shapes can be adopted using various materials.

[0066] In the above embodiment, the secondary charged particle detector 6 applies a scintillator, but the present invention is not limited to this, and other means capable of detecting various charged particles, electrons, and ions, such as a microchannel plate (MCP), can be applied.

[0067] In the above embodiment, a picoammeter is applied as the ammeter 8, but a configuration in which the ammeter 8 is omitted may also be used.

Explanation of Reference Numerals

[0068] IB Ion beam 1,1A Focused ion beam apparatus 2 Substrate support stage 3 Focused ion beam column 4 Head part 4A Internal space of the head 5 Differential evacuation part 6 Secondary charged particle detector 7 Movable seal valve 8 Ammeter 9 Valve drive part 10 Control part 11 Beam emission part 12 Substrate to be processed 13 Lens barrel 13A Internal space of the lens barrel 13B Connecting pipe 13C Tip opening of the lens barrel 14 Liquid metal ion source 15 Focused ion beam optical system 16 Condenser lens 17 Aperture 18 Astigmatism correction stigmator 19 Blanker 20 Blanking aperture 21 Deflector 22 Object lens 41 Upper main body 41A Column connection port 42 Lower main body 42A Lower main body opening 43 Groove forming plate 43A Head part tip opening (opening enabling beam irradiation) 43B Bottom surface 44, 45, 46 Annular groove 47, 48, 49, 50 Communication groove 51 Head plate 71 Rod part 72 Valve body 73 Vacuum pad 74 Metal mesh (adjustment reference pattern)

Claims

1. A beam emission unit including a focused ion beam optical system that adjusts and emits an ion beam drawn from an ion source into an internal space, and an opening that communicates with the internal space and allows the ion beam emitted from the beam emission unit to pass through to enable beam irradiation of a substrate to be processed. The focused ion beam apparatus is characterized in that the internal space is evacuated, comprising a movable sealing valve capable of opening and closing the opening, the internal space being provided with a secondary charged particle detector for detecting secondary charged particles, and an adjustment reference pattern being disposed at a position where the ion beam is irradiated when the opening is closed in the movable sealing valve. A focused ion beam apparatus characterized by this.

2. An ammeter is connected to the adjustment reference pattern, The focused ion beam apparatus according to claim 1.

3. The beam emission unit includes a focused ion beam column incorporating the focused ion beam optical system, and a head unit provided with a differential evacuation unit disposed at an end on the emission side of the focused ion beam column, The focused ion beam apparatus according to claim 1 or claim 2.

4. The internal space is a communicating space formed in the focused ion beam column and the head unit, and the opening is formed in the head unit, The focused ion beam apparatus according to claim 3.

5. The internal space is a space formed inside the focused ion beam column, and the opening is formed at an end on the emission side of the focused ion beam column, The focused ion beam apparatus according to claim 3.

6. The movable sealing valve is reciprocally driven between a position closing the opening and a standby position where the ion beam in the internal space is not irradiated, The focused ion beam apparatus according to claim 1 or claim 2.

7. The adjustment reference pattern is a metal mesh, The focused ion beam apparatus according to claim 1.

8. The ammeter is a picoammeter, The focused ion beam apparatus according to claim 2.

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