Focused ion beam device

Abstract

A focused ion beam device is provided, which includes a differential exhaust device and a focused ion beam column, and also includes: a vacuum pad, which has an intake surface exposed to surround the outside of the surface direction of a processed substrate and is made of a porous material; a substrate support table, which carries the processed substrate and the vacuum pad; and a vacuum pump, which performs vacuum suction on the vacuum pad. When the head of the differential exhaust device moves toward the outside of the surface direction of the processed substrate, the intake surface sucks the space between the intake surface and the head. The focused ion beam device does not require a large vacuum chamber and can process the vicinity of the periphery of the processed substrate, thereby increasing the processing area in the processed substrate.

Description

Technical Field

[0001] The present invention relates to a focused ion beam device having a differential exhaust device. Background Art

[0002] In recent years, a scanning electron microscope equipped with a local vacuum device at the front end of an ion beam irradiation device has been proposed (for example, refer to Patent Document 1). In this scanning electron microscope, a vacuum space can be locally formed on the surface of a sample by the local vacuum device, so a vacuum chamber is not required. In this scanning electron microscope, exhaust ports are provided at predetermined intervals along the direction in which the groove extends at the bottom of a groove between a sample mounted on a support member and a retreat member for retreating the ion beam irradiation device. In the above-mentioned scanning electron microscope, when the local vacuum device arranged on the retreat member is moved above the sample supported on the support member, the vacuum state of the vacuum region formed directly below the local vacuum device can be maintained.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-179751 Summary of the invention

[0006] Problems to be solved by the present invention

[0007] However, in the above-mentioned scanning electron microscope, the local vacuum device requires that the height level of the upper surface of the retreat member and the height level of the upper surface of the sample be matched with good accuracy. The reason is that if the height level of the upper surface of the retreat member and the height level of the upper surface of the sample are different, the gap between the side with the lower height level and the lower surface of the local vacuum device will become larger, and there is a case where a predetermined vacuum state cannot be maintained.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a focused ion beam apparatus that can process the vicinity of the periphery of a substrate to be processed using an ion beam without requiring a large vacuum chamber, thereby expanding a processing region in the substrate to be processed.

[0009] Solutions to Solve Problems

[0010] In order to solve the above-mentioned problems and achieve the purpose, the scheme of the present invention involves a focused ion beam device comprising: a differential exhaust device, which has a head portion opposite to an arbitrary area of ​​a processed surface of a processed substrate, an exhaust groove is formed in a manner surrounding the center of the head on an opposing surface of the head portion opposite to the processed surface, an opening portion is provided in an area inside the exhaust groove of the head portion, the opening portion forms a processing space capable of processing the processed surface, and the differential exhaust device sets the processing space to a high vacuum by utilizing the suction effect of the exhaust groove when the opposing surface is opposite to the processed surface; and a focused ion beam column, which is arranged on the side of the head portion opposite to the opposing surface and has an exhaust groove arranged thereon. The opening is connected to a lens barrel capable of communicating with the processing space, and a focused ion beam optical system is built into the lens barrel to emit an ion beam in a manner of passing through the opening. The focused ion beam device is characterized in that it also comprises: a vacuum pad, which is located outside the surface direction of the processed substrate, exposes a suction surface surrounding the processed substrate, and is made of a porous material; a substrate support table, which carries the processed substrate and the vacuum pad; and a vacuum pump, which performs vacuum suction on the vacuum pad, and when a part of the head moves to the outside in the surface direction closer to the peripheral portion of the processed substrate, the suction surface sucks the air in the space between the suction surface and the head to maintain the pressure of the processing space.

[0011] As the above aspect, it is preferred that the vacuum pad is formed only in a region surrounding the substrate to be processed, and an upper surface of the vacuum pad and a surface facing an outer peripheral surface of the substrate to be processed constitute the suction surface.

[0012] As the above aspect, it is preferable that when a part of the head moves outward in a surface direction of the substrate to be processed, the upper surface faces the facing surface of the head.

[0013] As the above-mentioned scheme, it is preferred that the vacuum pad is formed into a rectangular plate shape having a larger outline than the processed substrate, and is arranged on the upper surface of the substrate support table. The processed substrate and the support pad are arranged on the vacuum pad, and the support pad surrounds the outer side of the surface direction of the processed substrate with a gap of a specified width dimension.

[0014] As the above aspect, it is preferable that the support pad is made of a porous material.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to realize a focused ion beam apparatus that can process the vicinity of the periphery of a substrate to be processed and can increase a processing region in the substrate to be processed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram showing the structure of a focused ion beam device according to a first embodiment of the present invention.

[0018] Figure 2 It is a cross-sectional view of the main parts of the focused ion beam device according to the first embodiment of the present invention.

[0019] Figure 3 This is a bottom view of the differential exhaust device in the focused ion beam device according to the first embodiment of the present invention, as viewed from below.

[0020] Figure 4 It is an example of setting the upper surface of the vacuum pad to a height level lower than the upper surface of the processed substrate in the focused ion beam device of the first embodiment of the present invention, and is a cross-sectional illustration showing the state of the differential exhaust device being configured above the peripheral portion of the processed substrate.

[0021] Figure 5 1 is a schematic structural diagram of a focused ion beam apparatus according to a second embodiment of the present invention, and shows a state in which an optical alignment microscope is arranged above an alignment mark near the peripheral edge of a substrate to be processed.

[0022] Figure 6 1 is a schematic structural diagram of a focused ion beam apparatus according to a second embodiment of the present invention, and shows a state in which a differential exhaust device is located above a center portion of a substrate to be processed.

[0023] Figure 7 1 is a schematic structural diagram of a focused ion beam apparatus according to a second embodiment of the present invention, and shows a state in which a differential exhaust device is located above the peripheral portion of a substrate to be processed.

[0024] Figure 8 yes Figure 6 An enlarged illustration of the area A surrounded by a dotted line in FIG.

[0025] Fig. 9 yes Figure 7 An enlarged illustration of the area B surrounded by a dotted line in FIG.

[0026] Fig.10 This is a schematic diagram showing the structure of a focused ion beam device according to another embodiment of the present invention.

[0027] Fig.11 This is an enlarged explanatory diagram showing a case where there is no vacuum pad in the second embodiment (comparative example). DETAILED DESCRIPTION

[0028] The following is a detailed description of the focused ion beam device according to the embodiment of the present invention based on the accompanying drawings. It should be noted that the accompanying drawings are schematic, and the dimensions, ratios, numbers, shapes, etc. of the components are different from the actual ones. In addition, the drawings also include parts with different dimensional relationships, ratios, and shapes.

[0029] [First Embodiment] (Schematic Structure of Focused Ion Beam Device)

[0030] The focused ion beam device of this embodiment can be used to correct a photomask of a processed substrate, a TFT substrate, etc. It should be noted that the focused ion beam device of the present invention can also be applied to an exposure device that directly exposes the processed substrate, a scanning electron microscope that can observe the surface state of the processed substrate, etc.

[0031] Figure 1 The following is a schematic diagram of a focused ion beam apparatus 1 according to the first embodiment. The focused ion beam apparatus 1 includes a differential exhaust device 2, a focused ion beam column (hereinafter also referred to as a FIB column) 3, a substrate support 4, and an X-Y stage 5 for moving the substrate support 4 in the X-Y direction.

[0032] A vacuum pump 6 is connected to the FIB column 3 , and a predetermined low pressure can be maintained in the FIB column 3 . A stage control power supply 7 is connected to the XY stage 5 .

[0033] (Structure of substrate support table)

[0034] The substrate support table 4 includes a substrate support portion 4A and a peripheral support portion 4B. The substrate support portion 4A supports the substrate 8 to be processed while placing the substrate 8 thereon. The peripheral support portion 4B is formed along the peripheral portion of the substrate support portion 4A to surround the substrate support portion 4A.

[0035] A vacuum pad 40 made of a continuous porous material is arranged on the peripheral support portion 4B. The vacuum pad 40 is set in a frame shape so as to surround the substrate 8 to be processed arranged on the substrate support portion 4A with a predetermined groove portion (gap) 4C therebetween. The vacuum pad 40 is set to be exhausted to the lower side by a vacuum pump (not shown). The end portion (side wall of the inner peripheral edge) 41 of the vacuum pad 40 is exposed to the groove portion 4C as a suction surface.

[0036] In other words, the end portion 41 of the vacuum pad 40 forms the inner wall of the groove portion 4C. The vacuum pad 40 can be formed of, for example, a ceramic sintered porous body, a heat-resistant metal fiber filter material, or the like.

[0037] In the focused ion beam apparatus 1 of the present embodiment, the processing surface 8A of the processing substrate 8 placed on the substrate support 4A and the upper surface 40A of the vacuum pad 40 do not need to be at the same height level.

[0038] like Figure 4 As shown, the height level of the upper surface 40A of the vacuum pad 40 may be lower than the height level of the processed surface 8A. Figure 5 As shown, the height level of the upper surface 40A of the vacuum pad 40 may also be higher than the height level of the processed surface 8A.

[0039] Among them, the height level of the upper surface 40A of the vacuum pad 40 is to be set to the following height: when a part of the head 9 is moved from the periphery of the processed substrate 8 to the outside in the planar direction until it extends out while maintaining an appropriate gap G1 between the opposing surface (lower surface) 9A of the head 9 and the processed surface 8A, the vacuum pad 40 will not contact the head 9.

[0040] (Structure of differential exhaust device)

[0041] use Figure 1 to Figure 3 The structure of the differential exhaust device 2 is described below. Figure 3 It is a bottom view of the differential exhaust device 2. The differential exhaust device 2 includes a head 9 and a vacuum pump (not shown).

[0042] The head 9 is formed of a disk-shaped metal plate having an area extremely small compared to the area of ​​the processed surface 8A of the processed substrate 8. By moving the substrate support 4 in the XY direction using the XY stage 5, the head 9 can face any area of ​​the processed surface 8A.

[0043] like Figure 3 As shown, four annular grooves 10A, 10B, 10C, and 10D are concentrically formed on the facing surface 9A of the head 9. An opening 11 for forming a processing space Sp is provided in the inner region of the innermost annular groove 10A among the plurality of annular grooves 10A, 10B, 10C, and 10D of the head 9. In the processing space Sp, the processing surface 8A of the processing substrate 8 can be processed (film forming processing based on ion beam irradiation, etc.).

[0044] The FIB column 3 described later is connected to the opening 11 in a communicating manner. It should be noted that in this description, the groove formed in a manner surrounding the center of the head 9 is referred to as an "annular groove", which is a definition including a circular annular groove, a square annular groove, a C-shaped groove in which a part of the ring is missing, and a plurality of grooves arranged intermittently in an annular shape.

[0045] At least one (three in this embodiment) of the plurality of annular grooves 10A, 10B, 10C, and 10D is connected to the substrate via a connecting pipe 12 (see FIG. 1 ). Figure 2 ) is connected to a vacuum pump (not shown). The innermost annular groove 10A is connected to the vacuum pump via a connecting pipe 13 (see Figure 2 ) is connected to a deposition gas supply source (not shown) for supplying deposition gas (deposition gas, CVD gas).

[0046] The head 9 has a function of making the processing space Sp a low pressure by using the air suction effect from the annular grooves 10B, 10C, and 10D in a state where the facing surface 9A is facing the processed surface 8A. In addition, the head 9 reliably supplies the deposition gas from the innermost annular groove 10A to the processing space Sp adjusted to a low pressure, thereby enabling CVD film formation to be performed on the area of ​​the processed surface 8A facing the opening 11.

[0047] By setting a predetermined gap G1 between the facing surface 9A of the head 9 and the processed surface 8A while the facing surface 9A and the processed surface 8A are kept parallel, the vacuum state inside the processing space Sp can be maintained without destroying the high vacuum state.

[0048] (Focused ion beam column: FIB column)

[0049] like Figure 2 As shown, the FIB columnar body 3 is disposed on the surface side (upper surface side) opposite to the facing surface 9A of the head 9 , and the FIB columnar body 3 is connected to the head 9 in a state where the front end portion is embedded in the opening 11 of the head 9 .

[0050] The FIB column 3 includes a column 16 communicating with the processing space Sp and a focused ion beam optical system 17 built in the column 16. The ion beam Ib can be emitted from the front end of the FIB column 3 toward the processing surface 8A of the processing substrate 8 through the opening 11.

[0051] (Action / Effect)

[0052] The following describes the operation and function of the focused ion beam device 1 of this embodiment. In the focused ion beam device 1, the focused ion beam column 3 having the differential exhaust device 2 is moved relative to the substrate 8 to be processed, thereby enabling ion beam Ib to be irradiated to any position.

[0053] In the present embodiment, by setting the gap G1 between the facing surface 9A of the head 9 and the processed surface 8A of the processed substrate 8 to, for example, about 30 μm, the vacuum state inside the processing space Sp can be maintained without destroying the high vacuum state.

[0054] By moving the substrate support table 4 in the XY direction using the XY stage 5 , the head 9 of the differential exhaust device 2 can face any region of the processing surface 8A.

[0055] In this embodiment, even if the differential exhaust device 2 extends from the area of ​​the substrate 8 to be processed, a high vacuum state can be maintained due to the configuration of the vacuum pad 40. Figure 4 When the upper surface 40A of the vacuum pad 40 is lower than the periphery of the processed surface 8A of the processed substrate 8 as shown in the figure, the gap G2 between the upper surface 40A of the vacuum pad 40 and the opposing surface 9A of the differential exhaust device 2 is larger than the gap G1. In this case, the space below the area extending outward from the periphery of the processed substrate 8 in the opposing surface 9A of the head 9 is evacuated by the vacuum pad 40 and can maintain a high vacuum state.

[0056] In this state, if Figure 3 As shown, even when a portion of the facing surface 9A of the head 9 protrudes outward from the periphery of the substrate 8, appropriate processing using the ion beam Ib can be performed while maintaining an appropriate pressure in the processing space Sp.

[0057] In addition, Figure 4 In the structure shown, the end 41 of the vacuum pad 40 is exposed as a suction surface to the inner surface of the groove 4C, and air can also be sucked from the end 41. Therefore, the air stored in the inner space of the groove 4C and the air above the groove 4C is sucked by the end 41, thereby preventing the pressure above the groove 4C from rising.

[0058] (Effects of the Focused Ion Beam Device of the First Embodiment)

[0059] As described in the above-mentioned operation / effect, according to the focused ion beam device 1 of this embodiment, a large vacuum chamber is not required, and processing using the ion beam Ib can be reliably performed even near the peripheral portion of the substrate to be processed 8. Therefore, according to this embodiment, there is an effect of increasing the processable area of ​​the substrate to be processed 8.

[0060] According to the present embodiment, as described above, since the vacuum pad 40 is used to maintain the vacuum in the region where the differential exhaust device 2 extends from the substrate 8 to be processed, there is an advantage that the height level of the upper surface 40A of the vacuum pad 40 need not be strictly managed.

[0061] [Second embodiment]

[0062] Figure 6The following is a schematic diagram of a focused ion beam apparatus 1A according to a second embodiment of the present invention. The focused ion beam apparatus 1A includes a differential exhaust device 2, a FIB column 3, a substrate support table 4, a vacuum pad 42 disposed on the substrate support table 4, a fixed worktable 18 on which the substrate support table 4 is mounted, and an X-Y gantry worktable 19 mounted on the fixed worktable 18.

[0063] A moving block 20 that can move in the X-Y direction is provided on the X-Y gantry table 19. The FIB column 3, the vacuum pump 6 connected to the FIB column 3, and the optical calibration microscope 21 for detecting the calibration mark formed on the processed substrate 8 are fixed to the moving block 20. A gantry control power supply 22 is connected to the X-Y gantry table 19 side.

[0064] The vacuum pad 42 is arranged over substantially the entire upper surface of the substrate support table 4. The dimensions of the vacuum pad 42 are set so that the lengths thereof in both directions are longer than the substrate to be processed 8. A support pad 43 is arranged on the vacuum pad 42, and surrounds the substrate to be processed 8 when the substrate to be processed 8 is placed in the center of the vacuum pad 42. The support pad 43 is formed of a material through which air cannot pass.

[0065] The vacuum pad 42 is a continuous porous material and is connected to the vacuum pump 23. Therefore, by suctioning with the vacuum pump 23, it is set to suck air from the upper side of the vacuum pad 42. A groove portion 4C is formed as a gap between the substrate 8 to be processed and the inner peripheral surface of the support pad 43. The bottom surface of the groove portion 4C constitutes the suction surface where the vacuum pad 42 is exposed.

[0066] The vacuum pad 42 can be formed of, for example, a ceramic sintered porous body, a heat-resistant metal fiber filter material, or the like. Fig. 9 As shown, in the present embodiment, the support pad 43 is made of a glass plate which is made of the same glass material as the substrate 8 to be processed and has the same thickness as the substrate 8 to be processed.

[0067] In addition, in this embodiment, a glass plate is used as the support pad 43, but it is not limited to this, and a metal plate, a ceramic plate, etc. may also be applied.

[0068] The other structures of the focused ion beam apparatus 1A of the present embodiment are substantially the same as those of the focused ion beam apparatus 1 of the first embodiment described above, and thus detailed descriptions thereof are omitted.

[0069] In the focused ion beam apparatus 1A of the present embodiment, a vacuum pad 42 is arranged in the lower layer of the entire region where the substrate 8 and the support pad 43 are arranged, and the vacuum pad 42 suctions the substrate 8 and the support pad 43 .

[0070] like Figure 6As shown in the figure, when the head 9 of the differential exhaust device 2 is located above the center of the substrate 8, the substrate 8 is attracted by the head 9 and receives a force to bend upward. However, the substrate 8 is attracted downward by the vacuum pad 42 at the same time, so the force to bend upward is offset.

[0071] Figure 8 Yes means Figure 6 An enlarged illustration of the area A surrounded by a dotted line in FIG. Fig.11 It is an enlarged explanatory diagram showing a structure without a vacuum pad 42 (comparative example), showing the following state: when the vacuum pad 42 is not arranged under the lower layer of the processed substrate 8, the processed substrate 8 is lifted and warped by the suction force from the head 9 side.

[0072] Incidentally, the enlargement and thinning of the substrate 8 to be processed will become an obstacle when using the differential exhaust device 2 to form a local vacuum space to perform processing using the ion beam Ib. According to the focused ion beam device 1A of this embodiment, even a large-scale or thinned substrate 8 to be processed can be reliably supported on the substrate support part 4 while maintaining flatness. Therefore, in this embodiment, in a structure that uses the X-Y gantry worktable 19 for movement, high-precision processing can also be performed.

[0073] In the focused ion beam device 1A of this embodiment, the upper surface of the vacuum pad 42 is exposed at the bottom surface of the groove portion 4C serving as the gap, and vacuum is also performed from this portion. Figure 7 and Fig. 9 As shown, air can be sucked from the inner space of the groove portion 4C and the space above the groove portion 4C, and deterioration of the pressure above the groove portion 4C can be prevented.

[0074] It should be noted that since the upper surface of the vacuum pad 42 continuously exposes the bottom surface of the groove 4C formed around the substrate 8 to be processed, the pressure in the groove 4C at any position is kept uniform.

[0075] According to the present embodiment, there is an advantage that the width dimension of the groove portion 4C as the gap can be arbitrarily set by adjusting the output of the vacuum pump 23 .

[0076] According to the focused ion beam device 1A of this embodiment, a large vacuum chamber is not required, and the ion beam Ib can be reliably processed even near the peripheral edge of the substrate 8. Therefore, the focused ion beam device 1A has the effect of being able to effectively process a wide range of the substrate 8.

[0077] In the focused ion beam apparatus 1A of the present embodiment, a local vacuum space is realized using the differential pumping device 2 , whereby the area other than the area being processed is at atmospheric pressure, and thus the optical alignment microscope 21 can be easily installed.

[0078] In the case of calibration, e.g. Figure 5 The optical alignment microscope 21 is arranged at the position shown to detect an alignment mark (not shown) formed on the peripheral edge of the substrate 8. By detecting the alignment mark, the coordinates can be determined according to the relative relationship between the position of the optical alignment microscope 21 and the processing position of the FIB column 3.

[0079] Therefore, according to the focused ion beam apparatus 1A of the present embodiment, a stroke of the XY gantry stage 19 for calibration is unnecessary, and the movement time for calibration can be shortened.

[0080] In particular, in this embodiment, by providing the moving block 20 movable in the XY direction on the XY gantry table 19 , the FIB column 3 and the optical alignment microscope 30 provided on the moving block 20 can be moved while the position of the substrate 8 is fixed.

[0081] In this way, the position of the substrate 8 to be processed can be fixed, so the footprint of the device can be reduced.

[0082] Furthermore, according to the present embodiment, since the high vacuum of the processing space Sp of the head 9 can be reliably maintained, the quality of the processing work in the processing space can be improved.

[0083] Furthermore, according to the present embodiment, the device can be made compact, and thus the equipment cost and the management cost can be reduced.

[0084] [Other embodiments]

[0085] Although the embodiments of the present invention have been described above, it should not be understood that the discussion and drawings constituting part of the disclosure of these embodiments will limit the present invention. Various alternative embodiments, examples, and application technologies can be known to those skilled in the art based on this disclosure.

[0086] In the first embodiment described above, the vacuum pad 40 is placed on the upper surface of the peripheral support portion 4B so that the upper surface of the vacuum pad 40 is entirely exposed. Fig.10 As shown, the vacuum wall portion 44 exposed only inside the groove portion 4C is arranged along the groove portion 4C so as to surround the substrate 8 to be processed.

[0087] The surface of the vacuum wall 44 exposed in the groove 4C constitutes the suction surface of the present invention. In this embodiment, the upper surface of the peripheral support portion 4B is preferably at the same height as the processed surface 8A of the processed substrate 8 .

[0088] In the above-mentioned embodiments, the number of annular grooves formed in the differential exhaust device is not limited to four, as long as at least two annular grooves for exhaust and blowing are provided. In addition, circular annular grooves 10A, 10B, 10C, and 10D are formed as grooves for gas supply and exhaust, but the present invention is not limited thereto, and square annular grooves, for example, may also be formed.

[0089] In the second embodiment described above, the support pad 43 is formed of a material through which air cannot pass, but it may also be a structure composed of a porous material. In this case, the support pad 43 has the same function as the vacuum pad 40 in the first embodiment described above, and can improve the degree of freedom of the height level of the upper surface of the support pad 43 and prevent the processed substrate 8 from warping.

[0090] Explanation of symbols

[0091] Ib Ion beam

[0092] Sp Processing Space

[0093] 1 Focused ion beam device

[0094] 2 Differential exhaust

[0095] 3 Focused Ion Beam Column (FIB Column)

[0096] 4 Substrate support

[0097] 4A Board support part

[0098] 4B Peripheral support

[0099] 4C groove (gap)

[0100] 5X-Y workbench

[0101] 6 Vacuum pump

[0102] 7 Workbench control power supply

[0103] 8. Processed substrate

[0104] 8A Treated surface

[0105] 8B Lower surface

[0106] 9 Head

[0107] 9A Opposite side

[0108] 10A, 10B, 10C, 10D annular groove

[0109] 11 Opening

[0110] 12, 13 connecting pipe

[0111] 16 Lens tube

[0112] 17 Focused Ion Beam Optics

[0113] 18 Fixed workbench

[0114] 19X-Y gantry workbench

[0115] 20 Move Block

[0116] 21 Optical calibration microscope

[0117] 22 Gantry table control power supply

[0118] 23 Vacuum pump

[0119] 40 Vacuum pad

[0120] 40A upper surface (suction surface)

[0121] 41 end portion (surface facing the outer peripheral surface of the substrate to be processed: suction surface)

[0122] 42 Vacuum pad

[0123] 43 Support pad

[0124] 44 Vacuum wall

Claims

1. A focused ion beam device, comprising: A differential exhaust device, comprising a head facing an arbitrary area of ​​a processed surface of a processed substrate, an exhaust groove formed on an opposing surface of the head facing the processed surface in a manner surrounding the center of the head, an opening portion is provided in an area inside the exhaust groove of the head, the opening portion forms a processing space capable of processing the processed surface, and the differential exhaust device sets the processing space to a high vacuum by using an air suction effect from the exhaust groove in a state where the opposing surface faces the processed surface; as well as A focused ion beam columnar body is arranged on the side of the head opposite to the facing surface, and is provided with a lens barrel connected to the opening and capable of communicating with the processing space, wherein a focused ion beam optical system is built in the lens barrel to emit the ion beam in a manner of passing through the opening. The device for focusing ion beam is characterized in that: Also available: A vacuum pad, which is located outside the surface direction of the substrate to be processed, exposes a suction surface surrounding the substrate to be processed, and is made of a porous material; A substrate support table, which carries the substrate to be processed and the vacuum pad; as well as a vacuum pump for applying vacuum suction to the vacuum pad, When a part of the head moves outward from the peripheral edge of the substrate to be processed in the surface direction of the substrate to be processed, the suction surface sucks air in the space between the suction surface and the head to maintain the pressure of the processing space. The vacuum pad is formed only in a region surrounding the substrate to be processed, and an upper surface of the vacuum pad and a surface facing an outer peripheral surface of the substrate to be processed constitute the suction surface.

2. The focused ion beam device according to claim 1, wherein: When a part of the head moves outward in the surface direction of the substrate to be processed, the upper surface faces the facing surface of the head.

3. The focused ion beam device according to claim 1, wherein: The vacuum pad is formed into a rectangular plate shape having a larger outline than the substrate to be processed, and is arranged on the upper surface of the substrate support table. The substrate to be processed and a support pad are arranged on the vacuum pad. The support pad surrounds the outer side of the substrate to be processed in the surface direction with a gap of a predetermined width dimension.

4. The focused ion beam device according to claim 3, wherein: The support pad is made of a porous material.

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