Observation apparatus and sample stage control method

Abstract

To provide an observation device capable of reducing drift of a sample.SOLUTION: An observation device according to the present invention is an observation device for observing a sample, the observation device including a sample stage having a sample table on which the sample is placed, a first drive mechanism that displaces the sample table with respect to a first axis, and a second drive mechanism that displaces the sample table with respect to a second axis different from the first axis, and a control unit that controls the sample stage, when the control unit causes the first drive mechanism to execute a first operation of displacing the sample stage with respect to the first axis, the control unit performs a process of causing the second drive mechanism to execute a second operation for reducing a drift of the sample stage with respect to the second axis due to the first operation.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an observation apparatus and a method for controlling a sample stage. [Background technology]

[0002] Scanning electron microscopes, focused ion beam instruments, optical microscopes, and other instruments allow for the observation of minute regions of a sample. To observe such minute regions, the sample must be moved to the desired position and then maintained stationary. However, sample stages used to position the sample are prone to drift due to factors such as deflection of the mechanical components that make up the sample stage, backlash between mechanical components, and stress caused by the viscous resistance of the lubricants used on the mechanical components.

[0003] For example, Patent Document 1 discloses a technology for reducing drift that occurs in a sample stage in a stage movement device equipped with a motor that moves the stage, by reversing the rotation direction of the motor from the direction of rotation immediately before the stage stops when the movement of the stage stops. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-16367 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in Patent Document 1, the direction in which the sample stage is moved and the direction of drift are the same, but there are cases in which drift occurs in a direction different from the direction in which the sample stage is moved. [Means for solving the problem]

[0006] One aspect of the observation device according to the present invention is An observation device for observing a sample, comprising: a sample stage having a sample stage on which the sample is placed, a first drive mechanism for displacing the sample stage about a first axis, and a second drive mechanism for displacing the sample stage about a second axis different from the first axis; a control unit for controlling the sample stage; Including, When the control unit causes the first driving mechanism to perform a first operation to displace the sample stage relative to the first axis, it performs a process to cause the second driving mechanism to perform a second operation to reduce drift of the sample stage relative to the second axis that occurs due to the first operation.

[0007] In such an observation apparatus, it is possible to reduce drift of the sample stage about the second axis that occurs in the first operation of displacing the sample stage about the first axis.

[0008] One aspect of the sample stage control method according to the present invention includes: 1. A method for controlling a sample stage in an observation apparatus including a sample stage having a sample stage on which a sample is placed, a first drive mechanism that displaces the sample stage about a first axis, and a second drive mechanism that displaces the sample stage about a second axis different from the first axis, comprising: causing the first driving mechanism to perform a first operation to displace the sample stage relative to the first axis; a step of causing the second driving mechanism to perform a second operation for reducing drift of the sample stage about the second axis caused by the first operation when the first driving mechanism has performed the first operation for displacing the sample stage about the first axis; Includes:

[0009] In such a method for controlling a sample stage, it is possible to reduce drift of the sample stage about the second axis that occurs in the first operation for displacing the sample stage about the first axis. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an electron microscope according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of a control unit. [Figure 3] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 4] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 5] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 6] 10 is a flowchart showing an example of tilt processing by a control unit. [Figure 7] FIG. 10 is a diagram showing an example of the configuration of an electron microscope according to a second embodiment. [Figure 8] FIG. 2 is a diagram for explaining the operation of an electron microscope. [Figure 9] 10 is a flowchart showing an example of tilt processing by a control unit. [Figure 10] FIG. 10 is a diagram showing an example of the configuration of an electron microscope according to a third embodiment. [Figure 11] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 12] 10 is a flowchart showing an example of tilt processing by a control unit. [Figure 13] FIG. 10 is a diagram showing an example of the configuration of an electron microscope according to a fourth embodiment. [Figure 14] FIG. 2 is a diagram for explaining the operation of an electron microscope. [Figure 15] 10 is a flowchart showing an example of tilt processing by a control unit. [Figure 16] FIG. 10 is a diagram showing an example of the configuration of an electron microscope according to a fifth embodiment. [Figure 17] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 18] FIG. 4 is a diagram for explaining the operation of the sample stage. [Figure 19] 10 is a flowchart showing an example of an X movement process by the control unit. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0012] Furthermore, in the following, an electron microscope that observes a sample using an electron beam will be used as an example of the observation device according to the present invention, but the observation device according to the present invention is not limited to a scanning electron microscope and may be a device that observes a sample using electrons, ions, radiation, light (laser), or the like.

[0013] 1. First embodiment 1.1. Electron microscope First, an electron microscope according to a first embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of an electron microscope 100 according to the first embodiment. Fig. 1 illustrates three mutually orthogonal axes: an X-axis, a Y-axis, and a Z-axis. The X-axis, Y-axis, and Z-axis form a coordinate system that represents the position of a sample stage 16.

[0014] The electron microscope 100 observes a sample using electrons. The electron microscope 100 is a scanning electron microscope that focuses an electron beam to form an electron probe and scans a sample S with the electron probe to obtain a sample image. As shown in FIG. 1 , the electron microscope 100 includes a sample stage 10, a stage cooling mechanism 20, an electron optical system 30, and a control unit 40.

[0015] The sample stage 10 includes a T-drive mechanism 11, a Z-drive mechanism 12, an X-drive mechanism 13, a Y-drive mechanism 14, an R-drive mechanism 15, and a sample table 16. The sample stage 10 is a five-axis stage that can be displaced along five axes. The sample stage 10 can perform five movements: horizontal movement (X, Y), vertical movement (Z), tilt (T), and rotation (R).

[0016] The T driving mechanism 11 displaces the sample stage 16 about an axis T parallel to the X axis. The T driving mechanism 11 tilts the sample stage 16 about the axis T as a tilt axis. The T driving mechanism 11 includes a T stage 11a, a T power unit 11b, and a T power transmission member 11c.

[0017] The T-stage 11a tilts around axis T as the tilt axis. Axis T passes through the center of the T-stage 11a. The T-stage 11a tilts using a T-power unit 11b as a power source. The T-power unit 11b generates power for tilting the T-stage 11a. The T-power unit 11b is, for example, a motor. The T-power transmission member 11c is made up of multiple mechanical parts such as shafts, joints, and gears. The T-power transmission member 11c mechanically connects the T-power unit 11b and the T-stage 11a.

[0018] The Z drive mechanism 12 displaces the sample stage 16 relative to the Z axis. The Z drive mechanism 12 moves the sample stage 16 along the Z axis. That is, the Z drive mechanism 12 moves the sample stage 16 in the height direction of the sample S. The Z drive mechanism 12 includes a Z stage 12a, a Z power unit 12b, and a Z power transmission member 12c.

[0019] The Z stage 12a moves along the Z axis on the T stage 11a. The Z stage 12a moves using the Z power unit 12b as a power source. The Z power unit 12b generates power for moving the Z stage 12a. The Z power unit 12b is, for example, a motor. The Z power transmission member 12c is made up of multiple mechanical parts such as shafts, joints, and gears. The Z power transmission member 12c mechanically connects the Z power unit 12b and the Z stage 12a.

[0020] The X driving mechanism 13 displaces the sample stage 16 relative to the X axis. The X driving mechanism 13 moves the sample stage 16 along the X axis. That is, the X driving mechanism 13 moves the sample stage 16 in a direction perpendicular to the height direction of the sample S. The X driving mechanism 13 includes an X stage 13a, an X power unit 13b, and an X power transmission member 13c.

[0021] The X stage 13a moves along the X axis on the Z stage 12a. The X stage 13a moves using the X power unit 13b as a power source. The X power unit 13b generates power for moving the X stage 13a. The X power unit 13b is, for example, a motor. The X power transmission member 13c is made up of multiple mechanical parts such as shafts, joints, and gears. The X power transmission member 13c mechanically connects the X power unit 13b and the X stage 13a.

[0022] The Y drive mechanism 14 displaces the sample stage 16 along the Y axis. The Y drive mechanism 14 moves the sample stage 16 along the Y axis. That is, the Y drive mechanism 14 moves the sample stage 16 in a direction perpendicular to the height direction of the sample S. The Y drive mechanism 14 includes a Y stage 14a, a Y power unit 14b, and a Y power transmission member 14c.

[0023] The Y stage 14a moves on the X stage 13a along the Y axis. The Y stage 14a moves using a Y power unit 14b as a power source. The Y power unit 14b generates power for moving the Y stage 14a. The Y power unit 14b is, for example, a motor. The Y power transmission member 14c is made up of a plurality of mechanical parts such as shafts, joints, and gears. The Y power transmission member 14c mechanically connects the Y power unit 14b and the Y stage 14a.

[0024] The R drive mechanism 15 displaces the sample stage 16 along an R axis parallel to the Z axis. The R drive mechanism 15 rotates the sample stage 16 around the R axis. The R drive mechanism 15 includes an R stage 15a, an R power unit 15b, and an R power transmission member 15c.

[0025] The R stage 15a rotates on the Y stage 14a around the axis R as its rotation axis. The axis R passes through the center of the R stage 15a. The R stage 15a rotates using the R power unit 15b as its power source. The R power unit 15b generates power to rotate the R stage 15a. The R power unit 15b is, for example, a motor. The R power transmission member 15c is composed of multiple mechanical parts such as shafts, joints, and gears. The R power transmission member 15c mechanically connects the R power unit 15b and the R stage 15a.

[0026] The sample stage 16 is placed on the R stage 15a. A sample S is placed on the sample stage 16. An electron beam from an electron optical system 30 is irradiated onto the sample S placed on the sample stage 16.

[0027] 1, Z stage 12a is disposed on T stage 11a, X stage 13a is disposed on Z stage 12a, Y stage 14a is disposed on X stage 13a, R stage 15a is disposed on Y stage 14a, and sample stage 16 is disposed on R stage 15a. In this manner, T stage 11a, Z stage 12a, X stage 13a, Y stage 14a, R stage 15a, and sample stage 16 are disposed along the Z axis in this order. Note that the arrangement of each stage along the Z axis is not limited to the example shown in FIG. 1.

[0028] The stage cooling mechanism 20 cools the sample stage 10. By cooling the sample stage 10, the sample S can be cooled. By cooling the sample S, the morphology of the sample S can be observed at low temperatures. Furthermore, by cooling the sample S, damage to the sample S caused by the electron beam can be reduced. The stage cooling mechanism 20 includes a refrigerant tank 22 and a heat transfer member 24.

[0029] The coolant tank 22 is filled with, for example, liquid nitrogen. The heat transfer member 24 thermally connects the coolant tank 22 and the sample stage 16. The heat transfer member 24 is, for example, a flat braided wire. Note that the heat transfer member 24 is not limited to a flat braided wire, and may be a metal plate, a heat transfer wire, or the like. The heat transfer member 24 may also be a gas pipe that supplies a cooling gas to the sample stage 16, for example.

[0030] The electron optical system 30 is an optical system for irradiating the sample S with an electron beam. The electron optical system 30 includes an electron gun, a lens system, a scanning coil, etc. The electron optical system 30 focuses the electron beam to form an electron probe, and scans the sample S with the electron probe. Although not shown, the electron microscope 100 is equipped with a detector that detects electrons emitted from the sample S when the electron beam is irradiated onto the sample S. The electron microscope 100 can acquire a scanning electron microscope image (SEM image) by detecting the electrons emitted from the sample S with a detector while scanning the sample S with the electron probe using the electron optical system 30.

[0031] The control unit 40 controls the sample stage 10. Fig. 2 is a diagram showing an example of the configuration of the control unit 40. As shown in Fig. 2, the control unit 40 includes a processing unit 42, an operation unit 44, a display unit 46, and a storage unit 48.

[0032] The operation unit 44 is used by the user to input operation information, and outputs the input operation information to the processing unit 42. The functions of the operation unit 44 can be realized by input devices such as a keyboard, a mouse, buttons, a touch panel, and a touch pad.

[0033] The display unit 46 displays the image generated by the processing unit 42. The function of the display unit 46 can be realized by an LCD (Liquid Crystal Display), a touch panel display, or the like.

[0034] The storage unit 48 stores programs, data, etc. for the processing unit 42 to perform various calculation processes and various control processes. The storage unit 48 is also used as a working area for the processing unit 42, and is also used to temporarily store the results of calculations performed by the processing unit 42 in accordance with the various programs. The functions of the storage unit 48 can be realized by a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, etc.

[0035] The functions of the processing unit 42 can be realized by various processors such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a DSP (Digital Signal Processor) executing programs stored in the storage unit 48. The processing unit 42 includes a stage control unit 420 and a drift reduction unit 422.

[0036] The stage control unit 420 controls the sample stage 10. The stage control unit 420 controls the T drive mechanism 11, the Z drive mechanism 12, the X drive mechanism 13, the Y drive mechanism 14, and the R drive mechanism 15.

[0037] The drift reduction unit 422 performs a process for reducing the drift of the sample stage 16. When the drift reduction unit 422 causes the T driving mechanism 11 to perform a tilting operation (an example of a first operation) for displacing the sample stage 16 with respect to the axis T, the drift reduction unit 422 causes the Y driving mechanism 14 to perform a drift reduction operation (an example of a second operation) for reducing the drift of the sample stage 16 with respect to the Y axis that accompanies the tilting operation.

[0038] 1.2. Operation Next, a description will be given of the operation when tilting the sample stage 16 in the electron microscope 100. Figures 3 to 5 are diagrams for explaining the operation of the sample stage 10.

[0039] The initial position (coordinates) of the sample stage 16 shown in Figure 3 is expressed as (X, Y, Z, R, T) = (x1, y1, z1, r1, t1). Note that X represents the position of the sample stage 16 along the X axis, Y represents the position of the sample stage 16 along the Y axis, Z represents the position of the sample stage 16 along the Z axis, R represents the rotation angle around the axis R of the sample stage 16 as the rotation axis, and T represents the tilt angle around the axis T of the sample stage 16 as the tilt axis. Note that when the sample stage 16 is tilted around the axis T as the tilt axis, the Y axis and Z axis rotate around the X axis in response to the tilt of the sample stage 16.

[0040] As shown in Fig. 4, the sample stage 16 is tilted counterclockwise by Δt. When tilting the sample stage 16 counterclockwise by Δt, the T-stage 11a is tilted counterclockwise by Δt. As a result, the sample stage 16 moves from the initial position (x1, y1, z1, r1, t1) shown in Fig. 3 to the target position (x1, y1, z1, r1, t2) shown in Fig. 4.

[0041] 4, when the sample stage 16 is tilted, a force F1 in the +Y direction is applied to the sample stage 16 by the heat transfer member 24 connected to the sample stage 16. This causes a drift in the +Y direction on the sample stage 16. This drift of the sample stage 16 in the +Y direction is caused by the bending of the mechanical parts such as the shafts, joints, and gears that make up the Y power transmission member 14c when the force F1 in the +Y direction is applied to the sample stage 16, backlash between these mechanical parts, and stress caused by the viscous resistance of the lubricant used in these mechanical parts.

[0042] Therefore, when the tilting operation of the sample stage 16 is performed, the tilting of the sample stage 16 A drift reduction operation is performed to reduce drift relative to the Y axis. The drift reduction operation is an operation in which the sample stage 16 is moved in the +Y direction, which is the direction of force F1 applied to the sample stage 16, and then moved in the -Y direction. In other words, the drift reduction operation is an operation in which the sample stage 16 is swung from the target position in the +Y direction, and then swung back in the -Y direction to return the sample stage 16 to the target position.

[0043] Specifically, first, the Y stage 14a is moved by Δy in the +Y direction, whereby the sample stage 16 moves from the target position (x1, y1, z1, r1, t2) shown in Fig. 4 to the return position (x1, yA, z1, r1, t2) shown in Fig. 5.

[0044] Next, the Y stage 14a is moved by Δy in the −Y direction, whereby the sample stage 16 returns from the return position (x1, yA, z1, r1, t2) shown in FIG. 5 to the target position (x1, y1, z1, r1, t2) shown in FIG.

[0045] The swing amount Δy when the Y stage 14a is moved from the target position to the return position is a preset value and is constant regardless of the tilt angle in the tilt operation. Also, the return amount Δy when the Y stage 14a is moved from the return position to the target position is a preset value and is constant regardless of the tilt angle in the tilt operation. Here, the swing amount and the return amount are the same value (Δy), but they may be different values. The swing amount and the return amount are set to values ​​that reduce drift. The swing amount and the return amount can be determined, for example, by experiment or simulation.

[0046] The drift reduction operation can reduce the deflection of the multiple mechanical components constituting the Y power transmission member 14c due to the force F1 applied to the sample stage 16 and the stress caused by the viscous resistance of the lubricant used in the mechanical components. Furthermore, the drift reduction operation can change the posture of the heat transfer member 24, thereby reducing the force F1 applied by the heat transfer member 24 to the sample stage 16. Furthermore, the drift reduction operation moves the sample stage 16 from the return position in the direction opposite to the direction of force F1 and stops it at the target position. This allows the tooth surfaces of a pair of gears in the Y power transmission member 14c to come into contact with each other to prevent the gears from moving due to force F1. This reduces the drift of the sample stage 16 due to backlash between the mechanical components. Therefore, the drift reduction operation can reduce the drift of the sample stage 16 in the +Y direction caused by tilting the sample stage 16.

[0047] Although the above description has been given of the case where the sample stage 16 is tilted counterclockwise by Δt, the same applies to the case where the sample stage 16 is tilted clockwise by Δt. That is, when the sample stage 16 is tilted clockwise by Δt, the drift reduction operation is performed by moving the Y stage 14a in the −Y direction, which is the direction of the force applied to the sample stage 16, and then moving it in the +Y direction.

[0048] The direction of drift of the sample stage 16 when a tilting operation is performed is reproducible. Therefore, the direction of drift of the sample stage 16 when a tilting operation is performed can be known in advance by experiment, simulation, etc. Therefore, a control program is stored in advance in the storage unit 48 so that a drift reduction operation is performed when a tilting operation is performed.

[0049] Processing Next, a description will be given of the processing performed by the control unit 40 when tilting the sample stage 16. Fig. 6 is a flowchart showing an example of the tilt processing performed by the control unit 40.

[0050] The stage control unit 420 determines whether or not a tilt instruction to tilt the sample stage 16 has been given (step S100). The stage control unit 420 determines that a tilt instruction has been given when, for example, a user has input an instruction to tilt the sample stage 16 via the operation unit 44. The instruction includes information on the magnitude of the tilt angle and the tilt direction, which can be expressed, for example, by the rotation direction of the T-stage 11a, and is expressed as clockwise or counterclockwise in the example shown in Figure 3.

[0051] When the stage control unit 420 determines that a tilt instruction has been issued (Yes in step S100), it causes the T driving mechanism 11 to execute a tilt operation to tilt the sample stage 16 (step S102). Specifically, the stage control unit 420 causes the T power unit 11b to tilt the T stage 11a by the instructed tilt angle in the instructed tilt direction.

[0052] Next, the drift reduction unit 422 causes the Y drive mechanism 14 to perform the drift reduction operation (step S104). Specifically, when the sample stage 16 is tilted counterclockwise during the tilting operation, the drift reduction unit 422 causes the Y power unit 14b to move the Y stage 14a by Δy in the +Y direction and then by Δy in the -Y direction. Furthermore, when the sample stage 16 is tilted clockwise during the tilting operation, the drift reduction unit 422 causes the Y power unit 14b to move the Y stage 14a by Δy in the -Y direction and then by Δy in the +Y direction.

[0053] After causing the Y drive mechanism 14 to perform the drift reduction operation, the processing unit 42 ends the tilt processing.

[0054] Effects The electron microscope 100 includes a sample stage 10 having a sample stage 16 on which a sample S is placed, a T-drive mechanism 11 that displaces the sample stage 16 about an axis T, and a Y-drive mechanism 14 that displaces the sample stage 16 about a Y-axis different from the axis T, and a control unit 40 that controls the sample stage 10. When the control unit 40 causes the T-drive mechanism 11 to perform a tilting operation to displace the sample stage 16 about the axis T, the control unit 40 also causes the Y-drive mechanism 14 to perform a drift reduction operation to reduce drift of the sample stage 16 about the Y-axis that accompanies the tilting operation. Therefore, the electron microscope 100 can reduce drift of the sample stage 16 along the Y-axis that occurs when the sample stage 16 is tilted about the axis T.

[0055] Specifically, the T-drive mechanism 11 tilts the sample stage 16 around the axis T as the tilt axis. The Y-drive mechanism 14 moves the sample stage 16 along the Y-axis. The tilting operation is an operation in which the T-drive mechanism 11 tilts the sample stage 16 around the axis T as the tilt axis, and the drift reduction operation is an operation in which the Y-drive mechanism 14 moves the sample stage 16 in a first direction along the Y-axis and then moves it in a second direction opposite to the first direction. Therefore, in the electron microscope 100, it is possible to reduce drift of the sample stage 16 along the Y-axis, which occurs when the sample stage 16 is tilted around the axis T as the tilt axis.

[0056] The control method for the sample stage 10 in the electron microscope 100 includes the steps of causing the T drive mechanism 11 to perform a tilting operation to displace the sample stage 16 about the axis T, and, when the T drive mechanism 11 has performed the tilting operation to displace the sample stage 16 about the axis T, causing the Y drive mechanism 14 to perform a drift reduction operation to reduce drift of the sample stage 16 about the Y axis that accompanies the tilting operation. This makes it possible to reduce drift of the sample stage 16 along the Y axis that occurs when the sample stage 16 is tilted about the axis T.

[0057] 1.5. Variations 1.5.1. First variant In the first embodiment described above, the control unit 40 causes the Y driving mechanism 14 to perform the drift reduction operation when the control unit 40 causes the T driving mechanism 11 to perform the tilting operation of tilting the sample stage 16. However, the control unit 40 may also cause the Y driving mechanism 14 to perform the drift reduction operation when the control unit 40 causes the T driving mechanism 11 to perform the tilting operation of tilting the sample stage 16 by a predetermined angle or more. 0 causes the T drive mechanism 11 to perform a tilting operation to tilt the sample stage 16 by Δt, and when the magnitude of the tilt angle Δt is equal to or greater than a predetermined angle, causes the Y drive mechanism 14 to perform a drift reduction operation. On the other hand, the control unit 40 causes the T drive mechanism 11 to perform a tilting operation to tilt the sample stage 16 by Δt, and when the magnitude of the tilt angle Δt is less than the predetermined angle, does not cause the Y drive mechanism 14 to perform a drift reduction operation.

[0058] Here, when the tilt angle Δt when tilting the sample stage 16 is small, the drift of the sample stage 16 along the Y axis may be so small that it can be ignored. In the first modification, when the drift of the sample stage 16 is small, the drift reduction operation is not performed, and when the drift of the sample stage 16 is large, the drift reduction operation is performed.

[0059] 1.5.2. Second Variant In the first embodiment described above, when a tilting operation is performed to rotate the sample stage 16 counterclockwise, the sample stage 16 is moved by Δy in the +Y direction, and then a drift reduction operation is performed to move the sample stage 16 by Δy in the -Y direction. Also, when a tilting operation is performed to rotate the sample stage 16 clockwise, the sample stage 16 is moved by Δy in the -Y direction, and then a drift reduction operation is performed to move the sample stage 16 by Δy in the +Y direction. Thus, in the drift reduction operation, the swing amount when swinging the sample stage 16 from the target position to the return position and the return amount when returning the sample stage 16 from the return position to the target position are the same amount (Δy).

[0060] During the drift reduction operation, even if the swing and return distances are the same, the sample stage 16 may not return to the target position but may shift along the Y axis. This is due to the influence of backlash between the mechanical parts that make up the Y power transmission member 14c. The magnitude of the deviation of the sample stage 16 from the target position due to the influence of backlash varies depending on the combination of the movement direction of the Y stage 14a immediately before the drift reduction operation and the swing direction of the Y stage 14a during the drift reduction operation.

[0061] For example, even if the swing amount and return amount are the same, the amount of deviation from the target position after the drift reduction operation differs between the case where the Y stage 14a is moved in the +Y direction and then swung in the -Y direction in the drift reduction operation, and the case where the Y stage 14a is moved in the +Y direction and then swung in the +Y direction in the drift reduction operation. Similarly, even if the swing amount and return amount are the same, the amount of deviation from the target position after the drift reduction operation differs between the case where the Y stage 14a is moved in the +Y direction and then swung in the -Y direction in the drift reduction operation, and the case where the Y stage 14a is moved in the -Y direction and then swung in the -Y direction in the drift reduction operation.

[0062] Therefore, the drift reduction unit 422 sets the return amount in the drift reduction operation according to the combination of the movement direction of the Y stage 14a immediately before the drift reduction operation and the direction in which the Y stage 14a is swung during the drift reduction operation. Here, there are four combinations of the movement direction of the Y stage 14a immediately before the drift reduction operation (-Y direction or +Y direction) and the direction in which the Y stage 14a is swung during the drift reduction operation (-Y direction or +Y direction). Therefore, appropriate return amounts corresponding to these four combinations are stored in advance in the memory unit 48. The drift reduction unit 422 reads out the return amount from the memory unit 48 according to this combination and sets the return amount.

[0063] For example, if the movement direction of the Y stage 14a immediately before the drift reduction operation is the +Y direction, and the swing direction of the Y stage 14a in the drift reduction operation is the -Y direction, the drift reduction unit 422 reads out information on the return amount Δy' corresponding to this combination from the storage unit 48, and sets the return amount to Δy'. The drift reduction unit 422 moves the Y stage 14a by Δy in the -Y direction, and then moves it by Δy' in the +Y direction. This allows the drift reduction operation to be performed. The deviation of the sample stage 16 from the target position can be reduced.

[0064] 1.5.3. Third Variant In the electron microscope 100 according to the first embodiment described above, when the sample stage 16 is tilted, a force F1 is applied along the Y axis by the heat transfer member 24 connected to the sample stage 16. However, depending on the attachment position of the heat transfer member 24, when the sample stage 16 is tilted, a force along the X axis may be applied to the sample stage 16. In this case, the drift reduction unit 422 may cause the X drive mechanism 13 to perform a drift reduction operation. That is, when the sample stage 16 is tilted, the drift reduction unit 422 causes the X drive mechanism 13 to move the X stage 13a in the direction of the force generated by tilting the sample stage 16, and then causes the X stage 13a to move in the opposite direction, thereby performing a drift reduction operation.

[0065] Furthermore, in the electron microscope 100, when the sample stage 16 is tilted, if both a force along the X axis and a force along the Y axis are applied to the sample stage 16, the drift reduction unit 422 may cause both the X drive mechanism 13 and the Y drive mechanism 14 to perform drift reduction operations.

[0066] 1.5.4. Fourth Variant In the first embodiment described above, the heat transfer member 24 is connected to the sample stage 16, thereby applying a force F1 that causes drift to the sample stage 16. However, the member connected to the sample stage 16 that causes drift is not limited to the heat transfer member 24. The member connected to the sample stage 16 that causes drift may be a plate, a tube, a cable, or the like. Furthermore, the member that causes drift may be a member for controlling the state of the sample S, such as electric potential, magnetic field, light, sound, or vibration.

[0067] 2. Second embodiment 2.1. Electron microscope Next, an electron microscope according to a second embodiment will be described with reference to the drawings. Fig. 7 is a diagram showing an example of the configuration of an electron microscope 200 according to the second embodiment. Hereinafter, in the electron microscope 200 according to the second embodiment, components having the same functions as those of the electron microscope 100 according to the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0068] 7, the electron microscope 200 includes a measuring device 202 for measuring the weight of the sample S placed on the sample stage 16. As the measuring device 202, for example, a strain gauge, a pressure sensor, a spring, a displacement meter for measuring the displacement of the spring, or the like can be used.

[0069] The electron microscope 200 does not include a stage cooling mechanism 20 .

[0070] 2.2. Operation Next, a description will be given of the operation when tilting the sample stage 16 in the electron microscope 200. Figure 8 is a diagram for explaining the operation of the electron microscope 200.

[0071] 8, when the sample stage 16 is tilted, a force F2 in the +Y direction is applied to the sample stage 16 due to the weight of the sample S and the weight of the sample stage 16 itself. If the weight of the sample S is large, the force F2 becomes large, and the sample stage 16 drifts in the +Y direction.

[0072] Therefore, in the electron microscope 200, a drift reduction operation is performed when the weight of the sample S placed on the sample stage 16 is greater than a threshold value. The threshold value is set, for example, to the upper limit of the weight of the sample S at which no drift occurs on the sample stage 16. The threshold value can be set to any value.

[0073] Processing Next, a description will be given of the processing of the control unit 40 when tilting the sample stage 16. Fig. 9 is a flowchart showing an example of the tilt processing of the control unit 40. Below, differences from the example of tilt processing shown in Fig. 6 above will be described, and a description of similarities will be omitted.

[0074] The stage control unit 420 determines whether or not a tilt instruction to tilt the sample stage 16 has been issued (step S200).

[0075] When the stage control unit 420 determines that a tilt instruction has been issued (Yes in step S200), it causes the T driving mechanism 11 to execute a tilt operation to tilt the sample stage 16 (step S202).

[0076] Next, the drift reduction unit 422 acquires information on the weight of the sample S measured by the measuring device 202 (step S204). The drift reduction unit 422 compares the weight of the sample S with a threshold value and determines whether the weight of the sample S is greater than the threshold value (step S206).

[0077] When the drift reduction unit 422 determines that the weight of the sample S is greater than the threshold value (Yes in step S206), it causes the Y drive mechanism 14 to perform the drift reduction operation (step S208).

[0078] After causing the Y drive mechanism 14 to perform the drift reduction operation, or when it is determined that the weight of the sample S is equal to or less than the threshold value (No in step S206), the processing unit 42 ends the tilting process.

[0079] Effects The electron microscope 200 includes a measuring device 202 that measures the weight of the sample S placed on the sample stage 16, and the control unit 40 causes the Y drive mechanism 14 to perform a drift reduction operation when the weight of the sample S measured by the measuring device 202 is greater than a threshold value. Therefore, the electron microscope 200 can reduce drift along the Y axis of the sample stage 16 that occurs when the sample stage 16 is tilted.

[0080] 3. Third embodiment 3.1. Electron microscope Next, an electron microscope according to a third embodiment will be described with reference to the drawings. Fig. 10 is a diagram showing an example of the configuration of an electron microscope 300 according to the third embodiment. Hereinafter, in the electron microscope 300 according to the third embodiment, components having the same functions as those of the electron microscope 100 according to the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0081] In the electron microscope 300, various types of specimen stages 16 can be used on the specimen stage 10. For this reason, the electron microscope 300 includes a reader 302 that reads one-dimensional or two-dimensional barcodes attached to the specimen stage 16 to identify the type of specimen stage 16, as shown in FIG.

[0082] The reader 302 is, for example, a camera capable of reading one-dimensional barcodes and two-dimensional barcodes. The reader 302 reads the one-dimensional barcode or two-dimensional barcode and obtains information about the type of the specimen stage 16. The reader 302 sends the information about the type of the specimen stage 16 to the control unit 40. It should be noted that the electron microscope 300 does not include a stage cooling mechanism 20.

[0083] 3.2. Operation Next, a description will be given of the operation when tilting the sample stage 16 in the electron microscope 300. Figure 11 is a diagram for explaining the operation of the sample stage 10.

[0084] 11, when the sample stage 16 is tilted, a force F3 in the +Y direction is applied to the sample stage 16 due to the weight of the sample S and the weight of the sample stage 16. If the weight of the sample stage 16 is large, the force F3 becomes large, and the sample stage 16 drifts in the +Y direction.

[0085] Therefore, the electron microscope 300 determines whether or not to perform a drift reduction operation depending on the type of the specimen stage 16. The storage unit 48 stores in advance a list of specimen stages 16 (hereinafter simply referred to as "list") that cause drift in the specimen stage 16 when tilted.

[0086] Processing Next, a description will be given of the processing of the control unit 40 when tilting the sample stage 16. Fig. 12 is a flowchart showing an example of the tilt processing of the control unit 40. Below, differences from the example of tilt processing shown in Fig. 6 above will be described, and a description of similarities will be omitted.

[0087] The stage control unit 420 determines whether or not a tilt instruction to tilt the sample stage 16 has been issued (step S300).

[0088] When the stage control unit 420 determines that a tilt instruction has been issued (Yes in step S300), it causes the T driving mechanism 11 to execute a tilt operation to tilt the sample stage 16 (step S302).

[0089] Next, the drift reduction unit 422 acquires information on the type of the sample stage 16 being used from the reader 302 (step S304). The drift reduction unit 422 determines whether or not to cause the Y drive mechanism 14 to perform a drift reduction operation, depending on the information on the type of the sample stage 16. Specifically, the drift reduction unit 422 determines whether or not the type of the sample stage 16 identified from the information on the type of the sample stage 16 acquired in step S304 is registered in the list stored in the storage unit 48 (step S306).

[0090] When it is determined that the drift reduction unit 422 is registered in the list (Yes in step S306), the drift reduction unit 422 causes the Y drive mechanism 14 to perform the drift reduction operation (step S308).

[0091] After causing the Y drive mechanism 14 to perform the drift reduction operation, or when it is determined that the tilting operation is not registered in the list (No in step S306), the processing unit 42 ends the tilting operation.

[0092] Effects In the electron microscope 300, the control unit 40 acquires information on the type of the sample stage 16, and determines whether or not to perform processing to perform a drift reduction operation according to the acquired type of the sample stage 16. Therefore, in the electron microscope 300, it is possible to reduce drift along the Y axis of the sample stage 16 that occurs when the sample stage 16 is tilted.

[0093] 3.5. Variations In the third embodiment described above, the information on the type of the sample stage 16 is obtained by reading the one-dimensional or two-dimensional barcode attached to the sample stage 16 with the reader 302, but the means for obtaining the information on the type of the sample stage 16 is not limited to this. For example, an SEM image of the one-dimensional or two-dimensional barcode attached to the sample stage 16 may be obtained, and the one-dimensional or two-dimensional barcode in the SEM image may be read to obtain the information on the type of the sample stage 16. Alternatively, the user may input the information on the type of the sample stage 16 via the operation unit 44.

[0094] 4. Fourth embodiment 4.1. Electron microscope Next, an electron microscope according to a fourth embodiment will be described with reference to the drawings. Fig. 13 is a diagram showing an example of the configuration of an electron microscope 400 according to the fourth embodiment. Hereinafter, in the electron microscope 400 according to the fourth embodiment, components having the same functions as those of the electron microscope 100 according to the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0095] 13, the electron microscope 400 includes a sensor 402 that detects the position of the center of gravity of the sample stage 16 and the sample S when viewed as a unit. Note that the electron microscope 400 does not include a stage cooling mechanism 20.

[0096] 4.2. Operation Next, a description will be given of the operation when tilting the sample stage 16 in the electron microscope 400. Figure 14 is a diagram for explaining the operation of the electron microscope 400.

[0097] When tilting the sample stage 16 counterclockwise by Δt around the axis R as the tilt axis, the T-stage 11a is tilted counterclockwise by Δt, which moves the sample stage 16 from the initial position (x1, y1, z1, r1, t1) to the target position (x1, y1, z1, r1, t2).

[0098] 14, if the position of the center of gravity G when the sample S and the sample stage 16 are viewed as a single unit is not on the axis R, which is the rotation axis of the R stage 15a, when the sample stage 16 is tilted, a force F4 is applied to the sample stage 16 in the -Y direction. This causes a drift in the sample stage 16 that rotates around the axis R. In the example shown in FIG. 14, a drift in the sample stage 16 that rotates clockwise around the axis R occurs.

[0099] Therefore, when a tilting operation is performed to tilt the sample stage 16, a drift reduction operation is performed to reduce the drift of the sample stage 16 about the axis R that accompanies the tilting operation. The drift reduction operation is an operation in which the R stage 15a is rotated in the direction of the force F4 applied to the sample stage 16, i.e., clockwise, and then rotated in the opposite direction, i.e., counterclockwise.

[0100] Specifically, first, the R stage 15a is rotated clockwise by Δr, whereby the sample stage 16 moves from the target position (x1, y1, z1, r1, t2) to the return position (x1, y1, z1, rA, t2).

[0101] Next, the R stage 15a is rotated counterclockwise by Δr. As a result, the sample stage 16 returns from the return position (x1, y1, z1, rA, t2) to the target position (x1, y1, z1, r1, t2). This drift reduction operation reduces the rotational drift of the sample stage 16 around the axis R.

[0102] Although the above description has been given of the case where the sample stage 16 is tilted counterclockwise by Δt, the same applies to the case where the sample stage 16 is tilted clockwise by Δt. That is, when the sample stage 16 is tilted clockwise by Δt, the R stage 15a is rotated counterclockwise and then rotated clockwise.

[0103] Furthermore, the direction of drift (rotation direction) occurring in the sample stage 16 is determined by the direction in which the sample S is tilted and the position of the center of gravity G when the sample S and the sample stage 16 are viewed as a single unit. Therefore, in the electron microscope 400, the position of the center of gravity G is detected by the sensor 402. The direction in which the R stage 15a is rotated in the drift reduction operation is set according to the direction in which the sample S is tilted in the tilting operation and the detected position of the center of gravity G.

[0104] Processing Next, a description will be given of the processing of the control unit 40 when tilting the sample stage 16. Fig. 15 is a flowchart showing an example of the tilt processing of the control unit 40. Below, differences from the example of tilt processing shown in Fig. 6 above will be described, and a description of similarities will be omitted.

[0105] The stage control unit 420 determines whether or not a tilt instruction to tilt the sample stage 16 has been issued (step S400).

[0106] When the stage control unit 420 determines that a tilt instruction has been issued (Yes in step S400), it causes the T driving mechanism 11 to execute a tilt operation to tilt the sample stage 16 (step S402).

[0107] Next, the drift reduction unit 422 acquires information on the position of the center of gravity G when the sample stage 16 and the sample S are viewed as a single unit, which is detected by the sensor 402 (step S404). The drift reduction unit 422 determines whether the position of the center of gravity G is on the axis R (step S406).

[0108] If the drift reduction unit 422 determines that the position of the center of gravity G is not on the axis R (No in step S406), it causes the R drive mechanism 15 to perform a drift reduction operation (step S408). The drift reduction unit 422 sets the rotation direction of the R stage 15a according to the tilt direction of the sample S and the position of the center of gravity G, and rotates the R stage 15a in the rotation direction set in the R drive mechanism 15, and then causes the R stage 15a to perform a drift reduction operation by rotating it in the opposite direction.

[0109] After causing the R drive mechanism 15 to perform the drift reduction operation, or when it is determined that the center of gravity G is on the axis R (Yes in step S406), the processing unit 42 ends the tilting process.

[0110] Effects In the electron microscope 400, the T-drive mechanism 11 tilts the sample stage 16 about axis T as the tilt axis, and the R-drive mechanism 15 rotates the sample stage 16 about axis R, which is perpendicular to axis T. The tilting operation is an operation of tilting the sample stage 16 about axis T as the tilt axis, and the drift reduction operation is an operation of rotating the sample stage 16 in a first rotation direction and then in a second rotation direction opposite to the first rotation direction. Therefore, in the electron microscope 400, the drift of the sample stage 16 about axis R, which occurs when the sample stage 16 is tilted, can be reduced.

[0111] 5. Fifth embodiment 5.1. Electron microscope Next, an electron microscope according to a fifth embodiment will be described with reference to the drawings. Fig. 16 is a diagram showing an example of the configuration of an electron microscope 500 according to the fifth embodiment. Hereinafter, in the electron microscope 500 according to the fifth embodiment, components having the same functions as those of the electron microscope 100 according to the first embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0112] In the electron microscope 500, the position where the heat transfer member 24 is connected to the sample stage 16 is different from that of the electron microscope 100 shown in FIG.

[0113] 5.2. Operation Next, a description will be given of the operation when the sample stage 16 is moved along the X axis in the electron microscope 500. Figures 17 and 18 are diagrams for explaining the operation of the sample stage 10.

[0114] 17 and 18, the sample stage 16 is moved in the -X direction. When the sample stage 16 is moved in the -X direction, the X stage 13a is moved in the -X direction. As a result, the sample stage 16 moves from the initial position (x1, y1, z1, r1, t1) shown in FIG. 17 to the position shown in FIG. Move to the target position (x2, y1, z1, r1, t1).

[0115] 18, when the sample stage 16 is moved in the -X direction from its initial position, the heat transfer member 24 is deformed, and a force F5 in the +Y direction is applied to the sample stage 16 due to the deformation of the heat transfer member 24. This causes a drift in the +Y direction in the sample stage 16. This drift in the +Y direction of the sample stage 16 is caused by bending of the mechanical parts such as the shafts, joints, and gears that make up the Y power transmission member 14c when force F5 is applied to the sample stage 16 in the +Y direction, backlash between the mechanical parts, and stress caused by the viscous resistance of the lubricant used in the mechanical parts.

[0116] Therefore, when the sample stage 16 is moved in the -X direction, a drift reduction operation is performed to reduce the drift of the sample stage 16 relative to the Y axis that accompanies the movement. The drift reduction operation can reduce the deflection of the multiple mechanical components that make up the Y power transmission member 14c due to the force F5 applied to the sample stage 16 and the stress caused by the viscous resistance of the lubricant used in the mechanical components. Furthermore, the drift reduction operation can change the posture of the heat transfer member 24 to reduce the force F5 that the heat transfer member 24 applies to the sample stage 16. Furthermore, the drift reduction operation can reduce the drift of the sample stage 16 due to backlash between the mechanical components. Therefore, the drift reduction operation can reduce the drift of the sample stage 16 in the +Y direction caused by moving the sample stage 16 in the -X direction.

[0117] Specifically, first, the Y stage 14a is moved by Δy in the +Y direction, whereby the sample stage 16 moves from the target position (x2, y1, z1, r1, t1) shown in FIG.

[0118] Next, the Y stage 14a is moved by Δy in the -Y direction. As a result, the sample stage 16 returns from the return position (x2, yA, z1, r1, t1) to the target position (x2, y1, z1, r1, t1) shown in Figure 18. This reduces the drift of the sample stage 16 in the +Y direction.

[0119] Processing Next, the process of the control unit 40 when moving the sample stage 16 in the -X direction will be described. Fig. 19 is a flowchart showing an example of the X movement process of the control unit 40.

[0120] The stage control unit 420 determines whether or not there has been a movement instruction to move the sample stage 16 in the −X direction (step S500). The movement instruction includes information on the movement direction and movement amount of the sample stage 16.

[0121] If the stage control unit 420 determines that a movement instruction has been issued (Yes in step S500), it causes the X drive mechanism 13 to execute a movement operation to move the sample stage 16 in the -X direction (step S502). Specifically, the stage control unit 420 causes the X power unit 13b to move the X stage 13a by the instructed movement amount in the instructed movement direction.

[0122] Next, drift reduction unit 422 causes Y drive mechanism 14 to perform drift reduction operation (step S504). Specifically, drift reduction unit 422 causes Y power unit 14b to move Y stage 14a by Δy in the +Y direction, and then by Δy in the -Y direction. After causing control unit 40 to perform the drift reduction operation, control unit 40 ends the X movement process.

[0123] Effects The electron microscope 500 includes a heat transfer member 24 connected to the sample stage 16, and when the sample stage 16 is moved in the −X direction along the X axis, the heat transfer member 24 transfers heat to the sample stage 16 along the Y axis perpendicular to the X axis. The X drive mechanism 13 moves the sample stage 16 along the X axis, and the Y drive mechanism 14 moves the sample stage 16 along the Y axis. The movement operation is an operation of moving the sample stage 16 in the -X direction, and the drift reduction operation is an operation of moving the sample stage 16 in the +Y direction and then in the -Y direction opposite to the +Y direction. Therefore, in the electron microscope 500, the drift of the sample stage 16 in the +Y direction caused by moving the sample stage 16 in the -X direction can be reduced.

[0124] 5.5. Variations In the above-described fifth embodiment, a case has been described in which drift in the +Y direction of the sample stage 16 is reduced by moving the sample stage 16 in the -X direction, but drift that occurs when the sample stage 16 is moved in a direction other than the -X direction can also be reduced in the same way as in the fifth embodiment. For example, in an electron microscope in which drift in the +X direction occurs in the sample stage 16 when the sample stage 16 is moved in the -Y direction, when the sample stage 16 is moved in the -Y direction, a drift reduction operation may be performed in which the X stage 13a is moved in the +X direction and then in the -X direction.

[0125] 6. Sixth embodiment Next, an electron microscope according to a sixth embodiment will be described. Below, differences from the examples of the electron microscopes 100, 200, 300, 400, and 500 described above will be described, and a description of similarities will be omitted.

[0126] The electron microscope according to the sixth embodiment has the configuration of the electron microscope 100 shown in Fig. 1, the configuration of the electron microscope 200 shown in Fig. 7, the configuration of the electron microscope 300 shown in Fig. 10, the configuration of the electron microscope 400 shown in Fig. 13, and the configuration of the electron microscope 500 shown in Fig. 16. In other words, the electron microscope according to the sixth embodiment can function as the electron microscope 100, the electron microscope 200, the electron microscope 300, the electron microscope 400, and the electron microscope 500.

[0127] In the electron microscope according to the sixth embodiment, the processing unit 42 causes the display unit 46 to display a GUI (Graphical User Interface) screen for selecting the above-mentioned five functions of the electron microscope. The storage unit 48 stores control programs for causing the electron microscope to function as the above-mentioned five functions. When a function of the electron microscope is selected on the GUI screen, the processing unit 42 executes the control program corresponding to the selected function.

[0128] For example, when a user selects a function of the electron microscope 100 on the GUI screen, the processing unit 42 executes a control program for realizing the selected function of the electron microscope 100. As a result, the electron microscope according to the sixth embodiment functions as the electron microscope 100.

[0129] Note that multiple functions of the electron microscope may be selected on the GUI screen. For example, when the function of the electron microscope 100 and the function of the electron microscope 500 are selected, the electron microscope according to the sixth embodiment functions as the electron microscope 100 and the electron microscope 500. In this case, when a tilting operation that tilts the sample stage 16 is performed, or when an X movement operation that moves the sample stage 16 in the −X direction is performed, a drift reduction operation for the Y axis is performed.

[0130] 7. Variations The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention.

[0131] 7.1. First Variant In the first embodiment described above, when the sample stage 16 is tilted counterclockwise by Δt, a drift reduction operation is performed in the direction along the Y axis. When the sensor is tilted, in addition to the drift reduction operation in the direction along the Y axis, a drift reduction operation in the tilt direction may also be performed.

[0132] When the T-stage 11a is rotated counterclockwise to tilt the sample stage 16 counterclockwise, a drift occurs in the sample stage 16 that tilts the sample stage 16 counterclockwise. This is due to bending of the mechanical parts that make up the T-stage 11a, backlash between the mechanical parts, stress caused by the viscous resistance of the lubricant used in the mechanical parts, and the like.

[0133] As a drift reduction operation for the tilting operation of tilting the sample stage 16 counterclockwise, after tilting the T stage 11a counterclockwise from the target position, an operation of tilting the T stage 11a clockwise and returning it to the target position is performed. Thereby, the drift in the tilting direction of the sample stage 16 can be reduced.

[0134] The same applies to the second to fourth embodiments described above. Also, in the fifth embodiment described above, when the sample stage 16 is moved in the -X direction, in addition to the drift reduction operation for reducing the drift in the +Y direction of the sample stage 16, a drift reduction operation for reducing the drift in the -X direction of the sample stage 16 may be performed. The drift reduction operation for reducing the drift in the -X direction of the sample stage 16 is an operation of moving the X stage 13a in the -X direction from the target position and then moving it in the +X direction and returning it to the target position.

[0135] 7.2. Second Variant In the first embodiment described above, after the T drive mechanism 11 performed the tilting operation, the Y drive mechanism 14 performed the drift reduction operation. That is, after the T drive mechanism 11 performed the tilting operation and moved the sample stage 16 from the initial position (x1, y1, z1, r1, t1) to the target position (x1, y1, z1, r1, t2), the Y drive mechanism 14 performed the tilting operation and moved the sample stage 16 from the target position (x1, y1, z1, r1, t2) to the return position (x1, yA, z1, r1, t2), and then returned it from the return position (x1, yA, z1, r1, t2) to the target position (x1, y1, z1, r1, t2).

[0136] In contrast, in the first embodiment, while the T drive mechanism 11 is performing the tilting operation, the Y drive mechanism 14 may perform the drift reduction operation. For example, when tilting the sample stage 16 counterclockwise by Δt, first, the T drive mechanism 11 tilts the T stage 11a counterclockwise by Δt´ (t´ < t). Thereby, the sample stage 16 moves from the initial position (x1, y1, z1, r1, t1) to the intermediate position (x1, y1, z1, r1, t2´).

[0137] When the sample stage 16 is located at the intermediate position (x1, y1, z1, r1, t2'), the Y-drive mechanism 14 performs a drift reduction operation. As a result, the sample stage 16 moves from the intermediate position (x1, y1, z1, r1, t2') to the return position (x1, yA, z1, r1, t2'), and then returns from the return position (x1, yA, z1, r1, t2') to the intermediate position (x1, y1, z1, r1, t2').

[0138] Next, the T-drive mechanism 11 tilts the T-stage 11a counterclockwise by Δt-t', which moves the sample stage 16 from the intermediate position (x1, y1, z1, r1, t2') to the target position (x1, y1, z1, r1, t2).

[0139] In the second to fourth embodiments, the drift reduction operation may be performed while the tilting operation is being performed to move the sample stage 16 from the initial position to the target position, as in the first embodiment. Also, in the fifth embodiment, the drift reduction operation may be performed while the moving operation is being performed to move the sample stage 16 from the initial position to the target position, as in the first embodiment.

[0140] 7.3. Third Variant In the first to sixth embodiments described above, the observation apparatus according to the present invention is a scanning electron microscope that observes the sample S using electrons, but the observation apparatus according to the present invention may also be an apparatus that observes the sample using a charged particle beam such as electrons or ions, radiation such as X-rays, or light such as a laser. Examples of such observation apparatus include an electron probe microanalyzer (EPMA), an Auger microprobe, an electron beam lithography apparatus, an electron beam 3D printer, a focused ion beam apparatus (FIB), an ion beam processing apparatus such as a cross-section polisher (registered trademark), a photoelectron spectroscopy apparatus (XPS), an X-ray fluorescence analyzer (XRF), an optical microscope, a laser microscope, and a laser processing apparatus.

[0141] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0142] The present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the present invention includes configurations that are substantially identical to the configurations described in the embodiments. A substantially identical configuration means, for example, a configuration with the same function, method, and result, or a configuration with the same purpose and effect. The present invention also includes configurations in which non-essential parts of the configurations described in the embodiments are replaced. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations in which publicly known technology is added to the configurations described in the embodiments. [Explanation of symbols]

[0143] 10... Sample stage, 11... T drive mechanism, 11a... T stage, 11b... T power unit, 11c... T power transmission member, 12... Z drive mechanism, 12a... Z stage, 12b... Z power unit, 12c... Z power transmission member, 13... X drive mechanism, 13a... X stage, 13b... X power unit, 13c... X power transmission member, 14... Y drive mechanism, 14a... Y stage, 14b... Y power unit, 14c... Y power transmission member, 15... R drive mechanism, 15a... R stage, 15b ...R power unit, 15c...R power transmission member, 16...sample stage, 20...stage cooling mechanism, 22...refrigerant tank, 24...heat transfer member, 30...electron optical system, 40...control unit, 42...processing unit, 44...operation unit, 46...display unit, 48...storage unit, 100...electron microscope, 200...electron microscope, 202...measuring instrument, 300...electron microscope, 302...reader, 400...electron microscope, 402...sensor, 420...stage control unit, 422...drift reduction unit, 500...electron microscope

Claims

1. An observation device for observing a sample, comprising: a sample stage having a sample stage on which the sample is placed, a first drive mechanism for displacing the sample stage about a first axis, and a second drive mechanism for displacing the sample stage about a second axis different from the first axis; a control unit for controlling the sample stage; Including, The control unit, when causing the first driving mechanism to perform a first operation of displacing the sample stage relative to the first axis, performs a process of causing the second driving mechanism to perform a second operation of reducing drift of the sample stage relative to the second axis that occurs due to the first operation, in an observation device.

2. In claim 1, the first driving mechanism tilts the sample stage about the first axis as a tilt axis; the second driving mechanism moves the sample stage along the second axis perpendicular to the first axis; the first operation is an operation of tilting the sample stage about the first axis as a tilt axis, The second operation is an operation of moving the sample stage in a first direction along the second axis and then moving it in a second direction opposite to the first direction.

3. In claim 2, The observation apparatus, wherein the first operation is an operation of tilting the sample stage by a predetermined angle or more around the first axis as a tilt axis.

4. In claim 2, a measuring device for measuring the weight of the sample placed on the sample stage; The control unit performs the process when the weight of the sample measured by the measuring device is greater than a threshold value.

5. In claim 2, The control unit acquires information about the type of the sample stage, and determines whether or not to perform the processing depending on the acquired type of the sample stage.

6. In claim 1, the first driving mechanism tilts the sample stage about the first axis as a tilt axis; the second driving mechanism rotates the sample stage about the second axis perpendicular to the first axis, the first operation is an operation of tilting the sample stage about the first axis as a tilt axis, The second operation is an operation of rotating the sample stage in a first rotation direction and then rotating the sample stage in a second rotation direction opposite to the first rotation direction.

7. In claim 1, a member connected to the sample stage; the member applies a force to the sample stage in a second direction along the second axis perpendicular to the first axis when the sample stage is moved in a first direction along the first axis; the first drive mechanism moves the sample stage along the first axis; the second drive mechanism moves the sample stage along the second axis; the first operation is an operation of moving the sample stage in the first direction, The second operation is an operation of moving the sample stage in the second direction and then moving it in a third direction opposite to the second direction.

8. In any one of claims 1 to 7, The control unit causes the second driving mechanism to perform the second operation after the first driving mechanism has performed the first operation.

9. In any one of claims 1 to 7, The control unit causes the second drive mechanism to perform the second operation while the first drive mechanism is performing the first operation.

10. In any one of claims 1 to 7, an observation device including an optical system for irradiating the sample with a charged particle beam;

11. 1. A method for controlling a sample stage in an observation apparatus including a sample stage having a sample stage on which a sample is placed, a first drive mechanism that displaces the sample stage about a first axis, and a second drive mechanism that displaces the sample stage about a second axis different from the first axis, comprising: causing the first driving mechanism to perform a first operation of displacing the sample stage relative to the first axis; a step of causing the second driving mechanism to perform a second operation for reducing drift of the sample stage about the second axis caused by the first operation when the first driving mechanism has performed the first operation for displacing the sample stage about the first axis; A method for controlling a sample stage, comprising:

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