Fine-motion control system, scanning probe microscope, fine-motion unit control method, and scanning microscope control method

Abstract

In order to shorten the standby time of a fine-motion mechanism and effectively reduce vibration of the fine-motion mechanism, the present invention proposes a technique for controlling a fine-motion mechanism, comprising: setting the operating speed of the fine-motion mechanism during a first transition, which is a transition of the fine-motion mechanism from a first operating state to a second operating state different from the first operating state, and during a second transition, which is a transition from the second operating state to the first operating state, to a speed lower than the operating speed of the fine-motion mechanism in the first operating state and the second operating state by a period of time equivalent to (N - 1 / 2) cycles (N is a natural number) of the principal natural vibration of the fine-motion mechanism that occurs during the first transition or during the second transition; and causing the fine-motion mechanism to operate at the operating speed in the first operating state or the second operating state after the period of time equivalent to (N - 1 / 2) cycles has passed, and thus reducing vibration of the fine-motion mechanism that occurs during the first transition and during the second transition (see Fig. 2B).

Description

Fine movement control system, scanning probe microscope, fine movement unit control method, and scanning microscope control method

[0001] The present invention relates to a fine movement control system, a scanning probe microscope, a fine movement control method, and a scanning microscope control method.

[0002] A scanning probe microscope is a microscope that measures the surface shape and physical property information of a sample. Regarding such a scanning probe microscope, for example, Patent Documents 1 and 2 disclose that a probe formed at the tip of a cantilever is brought into contact with the sample and the probe is scanned continuously or intermittently to measure the shape of the sample surface.

[0003] JP 2001-33373 A JP 2011-209073 A

[0004] The fine-motion control systems used in scanning probe microscopes generally allow the user to set the scanning frequency, which is the frequency at which the probe scans the sample, to adjust the measurement speed. Furthermore, in measurement methods that involve intermittent probe scanning, a waiting time is set, during which the probe waits above the sample at each measurement point, to dampen vibrations that occur when the sample and probe are retracted. Because the measurement time for the shape of the sample surface depends on the scanning frequency and waiting time, increasing the scanning frequency and shortening the waiting time contribute to shortening the measurement time.

[0005] However, depending on the scanning frequency setting, the speed of the scanning probe or sample increases, and a large inertial force is applied when the probe or sample returns to its original position. This inertial force can cause the fine movement mechanism that drives the probe or sample in the in-plane direction to vibrate, potentially introducing noise due to the vibration into the measurement image.

[0006] Furthermore, in an intermittent measurement method such as that disclosed in Patent Document 2 (e.g., Sampling Intelligent Scan mode: SIS mode), a time (wait time) is provided during which the scanning operation is stopped until the vibrations have attenuated. However, this wait time tends to be relatively long, which affects the reduction of measurement time. On the other hand, depending on the setting of the wait time (if the wait time is too short), the vibrations generated when the sample and probe are retracted may not be fully attenuated, which may result in noise due to the vibrations appearing in the measurement image. Therefore, the current situation is that measurement time cannot be reduced.

[0007] The present invention has been made in view of the above circumstances, and proposes a fine movement control technique that shortens the standby time of the fine movement mechanism and effectively reduces vibrations of the fine movement mechanism.

[0008] In order to solve the above problem, the present invention proposes, as an example, a micro-motion control system comprising: a micro-motion unit that repeatedly transitions from a first operating state to a second operating state different from the first operating state, and from the second operating state to the first operating state; and a control device that controls the operation of the micro-motion unit, wherein the control device slows the operating speed of the micro-motion unit during the first transition and the second transition compared to the operating speed of the micro-motion unit in the first operating state and the second operating state for a time equivalent to (N-1 / 2) periods (N is a natural number) of the main natural vibration of the micro-motion unit that occurs during the first transition from the first operating state to the second operating state, or the second transition from the second operating state to the first operating state, and operates the micro-motion unit at the operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) period has elapsed, thereby reducing the vibration of the micro-motion unit that occurs during the first transition and the second transition.

[0009] Further features related to the present invention will become apparent from the description of this specification and the accompanying drawings. Also, aspects of the present invention are achieved and realized by the elements and combinations of various elements and the aspects of the following detailed description and the appended claims. The description of this specification is merely exemplary and does not limit the scope or application of the claims of the present invention in any way.

[0010] The fine movement control technique according to the present invention can reduce noise in measurement images due to vibrations. Furthermore, by applying the fine movement control technique to a scanning probe microscope, measurement time can be shortened.

[0011] Fig. 1 is a diagram showing an example of the schematic configuration of a fine movement control system 100 relating to the basic principle of this embodiment; Fig. 2 is a diagram showing stage displacement during normal reciprocating motion (when the waiting time (T shown below) of the present invention is not provided) and the waveform of vibration (fixed part displacement) caused by the normal reciprocating motion; Fig. 3 is a diagram showing stage displacement when a waiting time of half a period T of the natural vibration is provided at the turnaround point of the reciprocating motion and the waveform of vibration (fixed part displacement) caused by the reciprocating motion; Fig. 4 is a diagram showing an example of the configuration of a scanning probe microscope 200 relating to this embodiment;

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The fine movement control system of this embodiment is generally driven by an actuator such as a piezoelectric element or a quartz crystal oscillator. For example, it may have one or more drive axes.

[0013] (1) Basic Principle Fig. 1 is a diagram showing an example of the schematic configuration of a fine movement control system 100 according to the basic principle of this embodiment. As shown in Fig. 1, the fine movement control system 100 includes a fine movement unit 101, a support unit 102 that supports the fine movement unit 101, and a control unit (hereinafter also referred to as a "control device") 103 that controls the operation of the fine movement unit 101. The fine movement unit 101 is supported by the support unit 102, and is configured to reciprocate in response to a drive signal from the control unit 103. The control unit 103 can be configured as a computer.

[0014] <Vibration Reduction by Waiting Time Equal to Half a Cycle of Natural Vibration> An example of a vibration control method according to this embodiment will be described below with reference to FIG. 1 . When the fine movement unit 101 receives a drive signal from the control unit 103 and performs a reciprocating motion, a large acceleration is applied to the fine movement unit 101 in the direction opposite to the direction of travel in order to reverse the velocity vector of the fine movement unit 101 at the time of turning back. At this time (when turning back), the fine movement unit 101 may vibrate at its main natural frequency F. To reduce (avoid) the vibration of the fine movement unit 101, it is necessary to slow down the reciprocating motion of the fine movement unit 101 or to provide a waiting time (stop time) until the vibration attenuates. The natural frequency F of the fine movement unit 101 may be measured in advance by performing a reciprocating motion as shown in FIG. 2A .

[0015] 2A is a diagram showing the stage displacement during normal reciprocating motion (when the waiting time (T shown below) of the present invention is not provided) and the waveform of vibration (fixed part displacement) caused by normal reciprocating motion. The vibration waveform is a waveform that occurs when acceleration is applied at time t1 in the opposite direction to the previous direction of travel, and it can be seen that it decays over time. Conventionally, the time until this decay disappears was considered to be the waiting time.

[0016] However, as described above, this waiting time tends to be long. Therefore, in this embodiment, in order to reduce vibration, a waiting time of half the period T of the natural vibration of the fine movement unit 101 is provided. Specifically, when the fine movement unit 101 turns back in its reciprocating motion, the control unit 103 sets a waiting time (waiting in a stopped state) of half the period T of the natural vibration of the fine movement unit 101, as expressed by the following equation (1). As a result, a phase difference of half the period T of the vibration occurs between the vibration generated during deceleration before the turn and the vibration generated during acceleration after the turn. In other words, the vibrations are in opposite phases at the same time, and the vibrations of opposite phases cancel each other out, thereby suppressing vibration. The cancellation of the vibrations does not depend on the speed of the fine movement unit 101, and no waiting time is required until the vibrations attenuate, so high-speed turning operations can be achieved.

[0017] T=1 / 2F... (1)

[0018] Furthermore, although the standby time is set to a half period T in the above description, it may be set to a half period T' obtained by adding up one or more periods of vibration as expressed in the following equation (2).

[0019] T' = (2N + 1) / 2F (N is any positive integer) ... (2)

[0020] For example, when the micro-motion unit 101 receives a drive signal from the control unit 103 from a stationary state and starts driving, there is a possibility that vibration of the natural frequency F will occur due to acceleration immediately after driving, as described above (waiting time of half period T).

[0021] 2B is a diagram showing the waveforms of stage displacement and vibration (fixed part displacement) caused by the reciprocating motion when a waiting time of half a period T of the natural vibration is provided at the turning point of the reciprocating motion. As shown in FIG. 2B, in the fine movement control system 100, the fine movement unit 101 is stopped at time t1. At this time, as in FIG. 2A, an acceleration in the opposite direction to the previous traveling direction is applied for time t1 to stop the fine movement unit 101, generating a vibration waveform S1. Then, the control unit 103 stops (standbys) the fine movement unit 101, and after a time of half a period T of the natural vibration has elapsed, restarts the fine movement unit 101 with the original acceleration applied during the forward movement. When the fine movement unit 101 is restarted (when acceleration is applied), a vibration waveform S2 is generated. In this case, only the vibration waveform S1 appears from time t1 to time t1+T (or t1+T'), but from time t1 to time t1+T (or t1+T') onwards, a vibration waveform S2 appears, which has a phase difference of T or T', so that the vibration waveform S1 and the vibration waveform S2 cancel each other out, and vibration (noise) is reduced from time t1 to time t1+T (or t1+T') onwards.

[0022] <Vibration Reduction by Setting an Intermediate Speed ​​Band> The control unit 103 sets the intermediate speed band of the half cycle T or half cycle T' described above (for example, drive to a speed V1) when starting to drive the fine movement unit 101. As a result, the vibrations generated during acceleration from a stopped state to the intermediate speed band and the vibrations generated during acceleration from the intermediate speed band to a driven state (acceleration to a speed V2: V2 > V1) are in opposite phases at the same time, and the vibrations of the opposite phases cancel each other out, thereby suppressing the vibrations.

[0023] When the fine movement unit 101 receives a drive signal from the control unit 103 from a drive state (driven by accelerating to a speed V2) and stops driving, there is a possibility that vibrations of the natural frequency F will occur due to the acceleration immediately after deceleration, as described above. For this reason, the control unit 103 sets the intermediate speed band of the half period T or half period T' described above (for example, drive to a speed V1: V1 < V2) when the fine movement unit 101 decelerates and stops. As a result, vibrations generated when decelerating from the drive state (speed V2) to the intermediate speed band (speed V1) and vibrations generated when decelerating from the intermediate speed band (speed V1) to a stopped state (speed 0) are in opposite phases over the same time period, and the vibrations of the opposite phases cancel each other out, thereby suppressing the vibrations. <Regarding the adjustment mechanism for the standby time T / T'>

[0024] For example, if the main natural frequency F of the micro-movement unit 101 fluctuates, the operator needs to modify the waiting time T or the waiting time T'. In this case, a mechanism may be provided that allows the operator to adjust the setting of the waiting time T or the waiting time T' in the control unit 103. For example, a GUI for adjusting the waiting time may be displayed on a display device (not shown) connected to the control unit 103, allowing the operator to input the desired waiting time value. Each micro-movement unit 101 exhibits individual differences in vibration. Therefore, when setting an appropriate waiting time T, first, a reciprocating motion without a waiting time (e.g., a reciprocating motion as shown in FIG. 2A ) may be performed, and the control unit 103 may calculate the natural frequency F by reading the vibration waveform generated at that time. The control unit 103 may then display the calculated natural frequency F on the display screen of the display device, thereby presenting the value of the waiting time T to the operator.

[0025] (2) Application to Scanning Probe Microscopes The basic principle explained in the fine movement control system 100 of this embodiment can be used, for example, as a fine movement control system in a scanning probe microscope. It can also be used as a control system for devices that use piezoelectric elements or the like as a drive source.

[0026] <Configuration Example of Scanning Probe Microscope> Figure 3 is a diagram showing a configuration example of a scanning probe microscope 200 according to this embodiment. The scanning probe microscope 200 includes a cantilever 210, a movement drive unit 220, a displacement detection unit 230, and a control device 240. Here, the movement drive unit 220 corresponds to the fine movement unit 101 in the fine movement control system 100 of Figure 1. Furthermore, a bottom support unit (not shown) and / or a side support unit (not shown) that supports the movement drive unit 220 corresponds to the support unit 102. Furthermore, the control device 240 corresponds to the control unit 103. The control device 240 can be configured using a computer.

[0027] The scanning probe microscope 200 of this embodiment is an apparatus that measures the shape of a sample surface by contacting the probe with the sample surface and scanning the sample surface. The scanning probe microscope 200 scans the sample surface with the probe, for example, according to an intermittent measurement method (see Patent Document 2). Here, the intermittent measurement method is a method in which the probe is brought into contact (discretely contacted) with the sample surface and the sample surface is intermittently scanned with the probe. For example, the intermittent measurement method is called SIS (Sampling Intelligent Scan) mode. However, the scanning probe microscope 200 is not limited to one that performs sample surface scanning using the intermittent measurement method. The scanning probe microscope 200 may measure the shape of the sample surface by continuously scanning the probe across the sample surface while maintaining some kind of interaction between the probe and the sample constant.

[0028] For example, the scanning probe microscope 200 may measure the shape of the sample surface by scanning the surface of the sample while constantly bringing the probe into contact with the sample. Alternatively, for example, the scanning probe microscope 200 may measure the shape of the sample surface by scanning the surface of the sample while periodically bringing the probe into contact with the sample.

[0029] In Figure 3, a cantilever 210 has a probe 210a at its tip. The cantilever 210 has a fixed base end and a free tip end. The cantilever 210 is an elastic lever member with a small spring constant K. When the tip probe 210a comes into contact with the surface of a sample S (hereinafter referred to as the "sample surface"), the cantilever 210 deflects in accordance with the pressing force with which the tip probe 210a presses the sample surface. If the sample surface is tilted when the tip probe 210a comes into contact with the sample surface, the cantilever 210 will twist or deflect in accordance with the tilt of the sample surface and the fulcrum reaction force of the fulcrum, which is the contact point between the tip probe 210a and the sample surface.

[0030] The movement driver 220 is a fine movement mechanism that can move the probe 210a and the sample S relatively in three-dimensional directions. The movement driver 220 includes a Z-direction driver 221 and an XY scanner 222 (scanner unit).

[0031] A sample stage (sample stage) H is placed on the Z-direction driver 221. A sample S is placed on this sample stage H so as to face the probe 210a of the cantilever 210. The Z-direction driver 221 moves the sample stage H in a direction perpendicular to the horizontal plane (Z direction). For example, the Z-direction driver 221 can be configured with a scanner having a piezoelectric element. The Z-direction driver 221 moves the sample stage H in the Z direction under the control of the control device 240, thereby performing an operation of bringing the sample surface closer to the probe 210a or an operation of moving the sample S in a direction away from the probe 210a.

[0032] The XY scanner 222 moves the probe 210a and the sample S relatively in the X and Y directions under the control of the control device 240. In FIG. 3, the plane parallel to the surface of the sample stage H is the horizontal plane, and here the XY plane is defined by two orthogonal axes X and Y. For example, the XY scanner 222 can be configured with a piezoelectric element. The Z-direction driver 221 and the XY scanner 222 can be arranged in any positional relationship as long as they are configured to perform scanning relative to each other for three-dimensional shape observation. In other words, either cantilever scanning or sample scanning is acceptable.

[0033] The displacement detection unit 230 detects the amount of deflection and the amount of twist of the cantilever 210. For example, the displacement detection unit 230 can use an optical lever method to detect the amount of deflection and the amount of twist of the cantilever 210. The displacement detection unit 230 also includes a light irradiation unit 231 and a light detection unit 232.

[0034] The light irradiator 231 irradiates a laser beam L1 onto a reflective surface (not shown) formed on the back surface (first surface) C1 of the cantilever 210. The light detector 232 receives the laser beam L2 reflected by the reflective surface. The light detector 232 can be configured as a photodetector having four divided light-receiving surfaces 233 that receive the laser beam L2 reflected by the reflective surface. That is, the optical path from the light irradiator 231 to the light detector 232 via the cantilever 210 is adjusted so that the laser beam L2 reflected by the reflective surface of the cantilever 210 is incident on the four divided light-receiving surfaces 233 of the light detector 232. Note that, for example, the position of the light detector 232 is adjusted so that the laser beam L2 reflected by the reflective surface of the cantilever 210 is incident near the center of the light-receiving surface 233.

[0035] The determination unit 241 determines whether or not the probe 210a has come into contact with the sample surface based on the detection signal output from the light detection unit 232. The determination unit 241 also determines whether or not the probe 210a has moved away from the sample surface based on the detection signal output from the light detection unit 232.

[0036] The drive control unit 242 controls the relative movement amount between the probe 210a and the sample surface caused by the movement drive unit 220. More specifically, the drive control unit 242 applies feedback so that the relative position between the cantilever 210 and the sample S is always constant, and adjusts the height of the sample S by feedback control so that the position (irradiation position) of the laser light L1 is always located at the center of the light receiving surface 233. The drive control unit 242 supplies a contact operation signal to the Z-direction drive device 221 to bring the probe 210a into contact with the sample surface, and when the contact determination process determines that the probe 210a has contacted the sample surface, outputs a separation operation signal to the Z-direction drive device 221 to separate the sample surface from the probe 210a. Upon receiving the separation operation signal, the Z-direction drive device 221 lowers the sample S.

[0037] Furthermore, the drive control unit 242 outputs a drive signal to the XY scanner 222 to move the probe 210a to a measurement lowering position located immediately above the next measurement position.

[0038] The measurement unit 243 measures the shape of the sample surface while the probe 210a is in contact with the sample surface. For example, when the contact determination process determines that the probe 210a has come into contact with the sample surface, the measurement unit 243 measures the distance the sample S has moved relative to the probe 210a during the approach operation. In this way, the measurement unit 243 measures the surface shape of the sample S. For example, the measurement unit 243 may calculate the relative distance based on the voltage value of the contact operation signal when the probe 210a is in contact with the sample surface. Furthermore, the measurement unit 243 may directly measure the displacement of the sample stage H using a sensor, or may directly measure the height of the sample stage H using a sensor.

[0039] <Vibration Reduction of Movement Driver 220> Next, an example of a drive control method in the XY and Z directions that is applied to the scanning probe microscope 200 will be described.

[0040] (i) Vibration reduction based on the above-described basic principle: Reduction of vibrations (in the X and Y directions) that occur when the scanning operation (reciprocating motion) of the sample S is repeated. For example, the XY scanner 222 scans the surface of the sample S by repeatedly reciprocating the probe 210a and the sample S relative to each other in the X and Y directions under the control of the control device 240. During such reciprocating motion, a sudden change in the velocity vector occurs at the time of reciprocation, resulting in a momentary large acceleration. This acceleration causes the movement drive unit 220 to vibrate at its main natural frequency F (similar to FIG. 2A ). The vibration of the movement drive unit 220 is subject to feedback control by the determination unit 241 and the drive control unit 242 based on changes in the optical path of the laser light L2, which may cause erroneous detection of the shape of the sample S by the measurement unit 243.

[0041] Therefore, the control device 240 sets the waiting time T, expressed by the above formula (1), based on the main natural frequency F of the mobile drive unit 220, acquired in advance, at the timing of the return of the reciprocating scan. Note that the waiting time T' may also be the sum of one or more vibration cycles, as expressed by formula (2). This results in a phase difference of half a vibration cycle between the vibration generated during deceleration before the return and the vibration generated during acceleration after the return. These two vibrations are in opposite phases at the same time, and vibrations of opposite phases cancel each other out. Therefore, the vibrations of the mobile drive unit 220 after the return cancel each other out, preventing false detection by the measurement unit 43. The cancellation of the vibrations does not depend on the speed of the mobile drive unit 220, and no waiting time is required until the vibrations attenuate. This allows for high-speed return operations while preventing false detection. For example, a mechanism may be provided that allows an operator to correct (adjust) the value of the waiting time T or the waiting time T′ via the control device 240 when the natural frequency F of the movement drive unit 220 fluctuates.

[0042] (ii) Vibration Reduction by Setting the Intermediate Speed ​​Zone: Reduction of Vibrations Occurring in Intermittent Measurement Operations (Z Direction) As described above, the scanning probe microscope 200 can measure the surface of a sample using the intermittent measurement method. In the intermittent measurement method, at each measurement position, after an approach operation by the Z-direction driver 221, a contact determination is made by the determination unit 241, and a retraction operation is performed by the drive control unit 242 and the Z-direction driver 221, followed by a stopped state. The drive control unit 242 then outputs a drive signal to the XY scanner 222 to move the probe 210a to a measurement lowering position located directly above the next measurement position. The surface shape of the sample S is measured by measuring the approach distance at each measurement value.

[0043] For example, if an approach operation to the next measurement position is initiated immediately after a retraction operation, the retraction operation and the approach operation to the next measurement position will result in a sudden change in the velocity vector in the Z direction. This generates a large instantaneous acceleration, causing the movement drive unit 220 to vibrate at its main natural frequency F. If the approach operation is performed while the vibration is present, this may result in a false detection of the approach, making it difficult to accurately measure the approach distance. Therefore, a waiting time is provided between the retraction operation and the approach operation to the next measurement position to allow the vibration to decay (the time until the vibration decays, which is set in the intermittent measurement method: longer than the half-period T or (N+1 / 2) period T' of the vibration).

[0044] In this embodiment, in order to shorten the conventional waiting time and improve measurement throughput, the control device 240 sets an intermediate speed band in which the Z-direction drive device 221 is driven at an intermediate speed for a time T (a time equivalent to half a natural vibration cycle) calculated by the above formula (1) based on the main natural vibration frequency F of the movement drive unit 220, which has been previously acquired, when the probe 210a transitions from a retraction operation to a stopped state and from a stopped state to an approach operation. Here, the intermediate speed band does not only mean a speed band that is exactly half the retraction speed or approach speed, but also includes, for example, 40% of the retraction speed or 60% of the approach speed. Note that the time for driving at the intermediate speed band may be, for example, the time T' obtained by adding up one or more vibration cycles, as expressed in the above formula (2).

[0045] Specifically, for example, when transitioning from a retraction operation to a stopped state via the intermediate speed range, a phase difference of half a cycle occurs between the vibration occurring when transitioning from the retraction operation to the intermediate speed range and the vibration occurring when transitioning from the intermediate speed range to the stopped state. However, these two vibrations are in opposite phases at the same time, and the opposite-phase vibrations cancel each other out. Therefore, the vibration of the mobile drive unit 220 when transitioning from the retraction operation to the stopped state is reduced.

[0046] On the other hand, when transitioning from a stopped state to an approaching operation via the intermediate speed range, a phase difference of half a cycle occurs between the vibration occurring when transitioning from the stopped state to the intermediate speed range and the vibration occurring when transitioning from the intermediate speed range to the approaching operation. However, these two vibrations are in opposite phases at the same time, and the vibrations of the opposite phases cancel each other out. Therefore, the vibration of the movement drive unit 220 when transitioning from a stopped state to an approaching operation is reduced.

[0047] As described above, by providing an intermediate speed band of half the cycle T or (N+½) cycle T′ of the vibration of the mobile drive unit 220, the vibration of the mobile drive unit 220 is canceled out, making it possible to suppress erroneous detection by the measurement unit 243. The cancellation of vibrations does not depend on the speed of the mobile drive unit 220, and does not require the conventional waiting time until the vibrations attenuate, so high-speed approach and retraction operations can be performed while suppressing erroneous detection.

[0048] (iii) To summarize the reduction of vibrations in a scanning probe microscope 200 employing an intermittent measurement method, by setting a waiting time of half the period T or (N+1 / 2) period T' of vibration for vibrations that occur during the return movement of the reciprocating motion, and by setting an intermediate speed band of half the period T or (N+1 / 2) period T' of vibration for vibrations that occur during the approach and retraction movements during intermittent measurement, it is possible to reduce all vibrations that occur during intermittent measurement.

[0049] (3) The functions of the present embodiment can also be realized by software program code. In this case, a storage medium on which the program code is recorded is provided to a system or device, and the computer (or CPU or MPU) of the system or device reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-mentioned embodiment, and the program code itself and the storage medium on which it is stored constitute the present invention. Examples of storage media for providing such program code include flexible disks, CD-ROMs, DVD-ROMs, hard disks, optical disks, magneto-optical disks, CD-Rs, magnetic tape, non-volatile memory cards, and ROMs.

[0050] Furthermore, an operating system (OS) running on a computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing.Furthermore, after the program code is read from a storage medium and written to memory on the computer, a CPU of the computer may perform some or all of the actual processing based on instructions in the program code, and the functions of the above-described embodiments may be realized by this processing.

[0051] Furthermore, the program code of the software that realizes the functions of the embodiment may be distributed via a network and stored in a storage means such as a hard disk or memory of the system or device, or in a storage medium such as a CD-RW or CD-R, so that when used, the computer (or CPU or MPU) of the system or device reads and executes the program code stored in the storage means or storage medium.

[0052] The processes and techniques described herein are not inherently related to any specific device and can be implemented by combining components. Various types of general-purpose devices can also be added. A dedicated device may be constructed to perform the functions of this embodiment. Various functions can also be formed by appropriately combining multiple components disclosed in this embodiment and each example. For example, some components may be omitted from all the components shown in the embodiment and each example, or components from different examples may be appropriately combined.

[0053] Although specific embodiments are described in the present invention, they are in all respects for the purpose of explanation (understanding the technology of the present invention) and not for the purpose of limitation. Those skilled in the art will recognize that there are many combinations of hardware, software, and firmware suitable for implementing the technology of the present invention. For example, the described software can be implemented in a wide range of programming or scripting languages, such as assembler, C / C++, Perl, Shell, PHP, Java (registered trademark), etc.

[0054] Furthermore, in the above-described embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all control lines and information lines in the product are necessarily shown. All components may be interconnected.

[0055] In addition, other implementations of the present invention will become apparent to those skilled in the art from consideration of the present embodiments. The specification and examples are exemplary only, with the scope and spirit of the present technology being indicated by the following claims.

[0056] 100 Fine movement control system 101 Fine movement unit 102 Support unit 103 Control unit (control device) 200 Scanning probe microscope 210 Cantilever 210a Probe 220 Movement drive unit 221 Z-direction drive unit 222 XY scanner 230 Displacement detection unit 231 Light irradiation unit 232 Light detection unit 233 Light receiving surface 240 Control device 241 Determination unit 242 Drive control unit 243 Measurement unit

Claims

1. A micro-motion control system comprising: a micro-motion unit that repeats transitions from a first operating state to a second operating state different from the first operating state, and transitions from the second operating state to the first operating state; and a control device that controls the operation of the micro-motion unit, wherein the control device slows the operating speed of the micro-motion unit during the first transition and the second transition compared to the operating speed of the micro-motion unit in the first operating state and the second operating state for a time equivalent to (N-1 / 2) periods (N is a natural number) of the main natural vibration of the micro-motion unit that occurs during the first transition from the first operating state to the second operating state, or the second transition from the second operating state to the first operating state, and operates the micro-motion unit at the operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) period has elapsed, thereby reducing the vibration of the micro-motion unit that occurs during the first transition and the second transition.

2. A fine-motion control system as set forth in claim 1, wherein the first operating state is a forward movement in a first direction, and the second operating state is a forward movement in a second direction opposite to the first direction, and the control device applies acceleration in the direction opposite to the forward movement direction when the fine-motion unit transitions from the first direction to the second direction and when the fine-motion unit transitions from the second direction to the first direction, thereby causing the fine-motion unit to reciprocate.

3. A fine-motion control system as set forth in claim 1, wherein the control device stops the fine-motion unit for a time equivalent to the (N-1 / 2) cycle at the time of the first transition and the time of the second transition, and operates the fine-motion unit at the operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) cycle has elapsed.

4. A fine movement control system according to claim 1, wherein the first operating state is a driving state in which the fine movement unit is driving, and the second operating state is a stopped state in which the fine movement unit is stopped, and wherein the control device, at the second transition from the stopped state to the driving state of the fine movement unit, operates the fine movement unit at a first speed for a time equivalent to the (N-1 / 2) cycle, and after operating the fine movement unit at the first speed, operates the fine movement unit at a second speed faster than the first speed, and at the first transition from the driving state of the fine movement unit to the stopped state, decelerates the fine movement unit from the driving state at the second speed to the first speed for a time equivalent to the (N-1 / 2) cycle before stopping the fine movement unit.

5. A scanning probe microscope comprising: the fine movement control system according to claim 1; a cantilever having a probe; and a sample stage provided on the fine movement unit and on which a sample is placed.

6. A scanning probe microscope according to claim 5, wherein the micromotion unit includes an XY scanner that moves the sample stage in a horizontal direction, the first operating state is a driving state in which the XY scanner is driving, and the second operating state is a stopped state in which the XY scanner is stopped, and the control device stops the XY scanner for a time equivalent to the (N-1 / 2) period during the first transition and the second transition in the reciprocating motion of the sample stage in the horizontal direction by the XY scanner, and operates the XY scanner at the operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) period has elapsed.

7. A scanning probe microscope according to claim 5, wherein the fine movement unit includes a Z-direction drive device that moves the sample stage in the vertical direction, the first operating state is a drive state in which the Z-direction drive device is driving, and the second operating state is a stop state in which the Z-direction drive device is stopped, and the control device, when bringing the probe into contact with the sample via the drive state from the stop state, operates the Z-direction drive device at a first speed for a time equivalent to the (N-1 / 2) cycle, and after operating the Z-direction drive device at the first speed, operates the Z-direction drive device at a second speed faster than the first speed to bring the probe into contact with the sample, and when transitioning from the drive state in which the probe is retracted from the sample to the stop state, operates the Z-direction drive device at the second speed to move the probe away from the sample, and decelerates the probe to the first speed for a time equivalent to the (N-1 / 2) cycle before stopping the Z-direction drive device.

8. A method for controlling the operation of a micro-movement unit by a control device, which repeats a transition from a first operating state to a second operating state different from the first operating state, and a transition from the second operating state to the first operating state, the method comprising: operating the micro-movement unit at an operating speed during the first transition and the second transition slower than the operating speed of the micro-movement unit in the first operating state and the second operating state for a period equivalent to (N-1 / 2) periods (N is a natural number) of the main natural vibration of the micro-movement unit that occurs during a first transition from the first operating state to the second operating state, or a second transition from the second operating state to the first operating state; and operating the micro-movement unit at the operating speed in the first operating state or the second operating state after the period equivalent to the (N-1 / 2) period has elapsed, thereby reducing the vibration of the micro-movement unit that occurs during the first transition and the second transition.

9. A method for controlling a fine movement unit according to claim 8, wherein the first operating state is a forward movement in a first direction, and the second operating state is a forward movement in a second direction opposite to the first direction, and the control device applies acceleration in a direction opposite to the forward movement direction when the fine movement unit transitions from the first direction to the second direction and when the fine movement unit transitions from the second direction to the first direction, thereby causing the fine movement unit to reciprocate.

10. A method for controlling a micro-movement unit according to claim 8, wherein the control device stops the micro-movement unit for a time equivalent to the (N-1 / 2) cycle at the time of the first transition and the time of the second transition, and operates the micro-movement unit at the operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) cycle has elapsed.

11. A method of controlling a fine movement unit according to claim 8, wherein the first operating state is a driving state in which the fine movement unit is driving, and the second operating state is a stopped state in which the fine movement unit is stopped, and during the second transition from the stopped state to the driving state of the fine movement unit, operating the fine movement unit at a first speed for a time equivalent to the (N-1 / 2) cycle, and operating the fine movement unit at the first speed, and then operating the fine movement unit at a second speed faster than the first speed, during the first transition from the driving state of the fine movement unit to the stopped state, decelerating the fine movement unit from the driving state at the second speed to the first speed for a time equivalent to the (N-1 / 2) cycle, and then stopping the fine movement unit.

12. A scanning probe microscope control method for controlling a scanning probe microscope comprising a cantilever having a probe and a sample stage provided on the fine movement unit and on which a sample is placed, in accordance with the fine movement unit control method set forth in claim 8.

13. A method according to claim 12, wherein the fine movement unit includes an XY scanner that moves the sample stage in a horizontal direction, the first operating state is a driving state in which the XY scanner is driving, and the second operating state is a stopped state in which the XY scanner is stopped, and the method for controlling a scanning probe microscope comprises: stopping the XY scanner for a time equivalent to the (N-1 / 2) period during the first transition and the second transition in the reciprocating motion of the sample stage in the horizontal direction by the XY scanner; and operating the XY scanner at an operating speed in the first operating state or the second operating state after the time equivalent to the (N-1 / 2) period has elapsed.

14. A method according to claim 12, wherein the fine movement unit includes a Z-direction drive device that moves the sample stage in a vertical direction, the first operating state is a drive state in which the Z-direction drive device is driving, and the second operating state is a stop state in which the Z-direction drive device is stopped, and the method for controlling a scanning probe microscope comprises: when bringing the probe into contact with the sample by moving from the stop state to the drive state, operating the Z-direction drive device at a first speed for a time equivalent to the (N-1 / 2) cycle, and after operating the Z-direction drive device at the first speed, operating the Z-direction drive device at a second speed faster than the first speed to bring the probe into contact with the sample; when transitioning from the drive state in which the probe is retracted from the sample to the stop state, operating the Z-direction drive device at the second speed to move the probe away from the sample, and decelerating the probe to the first speed for a time equivalent to the (N-1 / 2) cycle before stopping the Z-direction drive device.

Images