Scanning Probe Microscope

Abstract

A control device performs control to: move an optical microscope while checking the focus thereof, from an initial position to a position in which the optical microscope is focused on an observation target (cantilever or sample) (S2); store information capable of specifying the relative positions of the optical microscope and the observation target in a state in which the optical microscope is focused (S3); if the optical microscope is to be newly focused on the observation target (cantilever or sample), move the optical microscope to the relative position on the basis of the stored information capable of specifying the relative position (S7); and then move the optical microscope while checking the focus, to a position in which the optical microscope is focused on the observation target (cantilever or sample) (S8).

Description

[Technical field]

[0001] The present invention relates to a scanning probe microscope. [Background technology]

[0002] In a scanning probe microscope, a probe tip formed at the tip of a cantilever is placed facing a sample. In a scanning probe microscope, changes in the bending or vibration of the cantilever brought close to the sample are converted into changes in the reflected light of a laser irradiated onto the back of the cantilever, and detected by a photodetector. The photodetector detects changes in the position, intensity, phase, etc. of the reflected light. A scanning probe microscope measures various physical information of the sample by converting the information detected by the photodetector into various physical information.

[0003] In a scanning probe microscope, in order to observe the state of an observation object such as a sample or a cantilever, an optical microscope is placed at a position where it is possible to obtain a magnified image of the observation object within the observation area including the sample and the cantilever.

[0004] In a scanning probe microscope, before measuring a sample, the optical axis of the laser beam is adjusted so that the laser beam is correctly irradiated onto the back surface of the cantilever. When the optical axis of the laser beam is adjusted, it is necessary to focus the optical microscope on the object to be observed, such as the back surface of the cantilever, in order to confirm that the laser beam is correctly irradiated onto the back surface of the cantilever.

[0005] When focusing the optical microscope on the object to be observed, an operation of focusing the optical microscope on the object to be observed is performed by moving the position of the optical microscope, for example by moving the optical microscope from an initial position, such as the position farthest from the object to be observed, toward the object to be observed to a position where the optical microscope is focused on the object to be observed.

[0006] When performing an operation to focus an optical microscope on an object to be observed, it is necessary to move the optical microscope over a relatively wide range while checking whether the optical microscope is focused on the object to be observed by performing image processing of the object to be observed within the observation area based on the image obtained by the optical microscope.

[0007] As an example of a technique for adjusting the optical axis of a laser beam, Patent Document 1 (Japanese Patent No. 6627953) discloses a scanning probe microscope equipped with an image processing unit that identifies the position of the laser beam spot and the position of the tip of the cantilever based on an image. The scanning probe microscope disclosed in Patent Document 1 further includes an optical axis adjustment unit that adjusts the position of the laser light source based on the identified position of the laser beam spot and the position of the tip of the cantilever. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6627953 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in conventional scanning probe microscopes, in order to focus the optical microscope on the object to be observed, the optical microscope is moved over a relatively wide range while image processing is performed to check whether the optical microscope is focused on the object to be observed. This places a limit on the speed at which the optical microscope can be moved to focus on the object to be observed. And, the limit on the speed at which the optical microscope can be moved causes a problem in that it takes a long time to focus the optical microscope on the object to be observed.

[0010] The present invention has been made to solve such problems, and its object is to shorten the time required to focus an optical microscope. [Means for solving the problem]

[0011] A scanning probe microscope according to one aspect of the present invention includes a cantilever including a probe arranged facing a sample, an optical microscope arranged at a position where a magnified image of an observation object in an observation area including the cantilever and the sample can be acquired, a first drive source that operates to move the observation object, a second drive source that operates to move the optical microscope, and a control device that controls the first drive source and the second drive source. The control device moves the optical microscope from an initial position to a position where the optical microscope is focused on the observation object while checking the focus, stores information that can specify the relative position between the optical microscope and the observation object in the focused state, and when focusing the optical microscope on a new observation object, moves the optical microscope to the relative position based on the stored information that can specify the relative position, and then controls the optical microscope to move to a position where the optical microscope is focused on the observation object while checking the focus.

[0012] A scanning probe microscope according to another aspect of the present invention includes a cantilever including a probe positioned facing a sample, an optical microscope positioned at a position where a magnified image of the cantilever can be obtained, a first pulse motor operated to move the cantilever, a second pulse motor operated to move the optical microscope, and a control device that controls the first pulse motor and the second pulse motor. The control device is capable of controlling the cantilever to be moved from a first initial position by a distance corresponding to the number of first pulses supplied to the first pulse motor, and is capable of controlling the optical microscope to be moved from a second initial position by a distance corresponding to the number of second pulses supplied to the second pulse motor, and moves the optical microscope from the second initial position to a position where the optical microscope is focused on the cantilever while checking the focus, stores the number of first pulses and the number of second pulses supplied that can identify the relative position of the optical microscope and the cantilever in the focused state, and when focusing the optical microscope on the cantilever for the first time, moves the optical microscope until the relative position is reached based on the stored number of first pulses and the number of second pulses supplied, and then controls the optical microscope to be moved while checking the focus to a position where the optical microscope is focused on the cantilever. Effect of the Invention

[0013] The time required to focus an optical microscope can be shortened. [Brief description of the drawings]

[0014] [Figure 1] 1 is a side view showing a schematic configuration of a main structure of a scanning probe microscope 1 according to an embodiment of the present invention. [Diagram 2] 1 is a block diagram showing a schematic configuration of the main structure and control circuit of a scanning probe microscope 1 of an embodiment. [Diagram 3] 13 is a flowchart of a focus adjustment process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are given the same reference characters, and their descriptions will not be repeated in principle.

[0016] [Main structure and control circuit configuration of scanning probe microscope 1] Fig. 1 is a side view showing a schematic configuration of the main structure of a scanning probe microscope 1 of an embodiment. Fig. 2 is a block diagram showing a schematic configuration of the main structure and control circuit of a scanning probe microscope 1 of an embodiment. In the following description, the ground plane of the scanning probe microscope 1 is defined as the XY plane, and the axis perpendicular to the XY plane is defined as the Z axis.

[0017] 1 and 2, a scanning probe microscope 1 comprises, as main components, a cantilever 2, a holder 41, a head 4, a case 5, an optical system 20, driving devices 30, 40, a scanner 7, a sample holder 6, an optical microscope 9, driving circuits 31, 32, 33, a first pulse motor 8, a second pulse motor 10, motor shafts 81, 11, a connecting mechanism 82, and a control device 100. In order to clarify the configuration of the control system, a diagram of the head 4 is shown with a portion thereof omitted.

[0018] The cantilever 2 is provided so as to be located above the sample S placed on the sample holding part 6 during measurement of the sample S. The cantilever 2 has one end, or the rear end, supported by a holder 41 so as to be movable in the vertical direction, and has a probe 3 at the other end, or the tip end.

[0019] The holder 41 is attached to one of the arm members of the head 4, which is composed of a plurality of arm members connected and interlocked by a connecting mechanism 82. The holder 41 moves up and down in the Z-axis direction in accordance with the up and down movement of the head 4, which is movable up and down in the Z-axis direction. The head 4 is driven up and down in the Z-axis direction by a driving mechanism 50, which is an operating direction conversion mechanism configured by meshing a screw part 51 formed in a part covered by a cylindrical case 5 in which a part of the Z-direction members is stored, with a gear 52 coaxially attached to a motor shaft 81 of the first pulse motor 8. In the driving mechanism 50, the rotational movement of the motor shaft 81 is converted into a moving movement of the head 4 in the Z direction. The head 4 can also be moved in the XY direction by a driving mechanism other than the driving mechanism 50.

[0020] The drive circuit 31 drives the first pulse motor 8 as a drive source by supplying pulses to the first pulse motor 8. The drive circuit 32 drives the second pulse motor 10 as a drive source by supplying pulses to the second pulse motor 10. The first pulse motor 8 rotates a first amount of rotation every time one pulse is supplied. The second pulse motor 10 rotates a second amount of rotation every time one pulse is supplied.

[0021] During measurement, the optical system 20 irradiates the back surface of the cantilever 2 (the surface opposite to the front surface facing the sample S) with laser light LA ​​and detects the laser light LA ​​reflected by the back surface of the cantilever 2. The control device 100 calculates the deflection of the cantilever 2 based on the laser light LA ​​detected by the optical system 20. The optical system 20 includes a laser light source 24, a beam splitter 21, a reflecting mirror 22, and a detector 23.

[0022] The laser light source 24 is composed of a laser oscillator that emits laser light LA, etc. The laser light LA ​​emitted from the laser light source 24 is reflected by the beam splitter 21 and irradiated onto the cantilever 2. The laser light LA ​​irradiated onto the cantilever 2 is reflected by the rear surface of the cantilever 2, and further reflected by the reflecting mirror 22, and is incident on the detector 23. The detector 23 has a light receiving surface 230 for receiving the laser light LA ​​reflected by the rear surface of the cantilever 2. The detector 23 detects the laser light LA ​​received by the light receiving surface 230, and outputs the obtained detection result to the control device 100.

[0023] The driving device 30 includes a driving source consisting of a motor, and a driving mechanism that moves the laser light source 24 by the driving force of the driving source. The driving device 30 moves the laser light source 24 along a plane (YZ plane in the example shown in FIG. 1) perpendicular to the optical axis of the laser light LA ​​emitted from the laser light source 24. The driving device 30 drives the motor in accordance with a control signal from the control device 100, thereby moving the laser light source 24, and the optical axis of the laser light LA ​​is adjusted so that the laser light LA ​​is reflected by the cantilever 2.

[0024] The driving device 40 includes a driving source consisting of a motor, and a driving mechanism that moves the detector 23 by the driving force of the driving source. The driving device 40 moves the detector 23 along a plane (YZ plane in the example shown in FIG. 1) perpendicular to the optical axis of the laser light LA ​​reflected by the reflecting mirror 22 and incident on the light receiving surface 230. The driving device 40 moves the detector 23 by, for example, driving the motor according to a control signal from the control device 100, and the position of the detector 23 is adjusted so that the laser light LA ​​reflected by the cantilever 2 is incident on the center of the light receiving surface 230.

[0025] The scanner 7 has a cylindrical shape. The sample S is held on a sample holder 6 placed on the scanner 7. The scanner 7 has an XY scanner that scans the sample S in two mutually perpendicular axial directions, X and Y, and a Z scanner that slightly moves the sample S in the Z axis direction perpendicular to the X and Y axes. The XY scanner and the Z scanner are driven by piezoelectric elements that are deformed by a voltage applied from a drive circuit 33. The scanner 7 is driven in three dimensional directions by the XY scanner and the Z scanner.

[0026] The driving circuit 33 drives the scanner 7 in three dimensional directions (X-axis direction, Y-axis direction, and Z-axis direction) by applying a voltage to a piezoelectric element included in the scanner 7. In this way, the driving circuit 33 can change the relative positional relationship between the probe 3 and the sample S placed on the sample holder 6 on the scanner 7.

[0027] The optical microscope 9 is disposed above the probe 3, and is capable of acquiring an enlarged image of the observation object by capturing an image of the observation area including the observation object, the cantilever 2 and the sample S, using an image sensor or the like. The optical microscope 9 captures an image of the observation object present in the imaging field of view to acquire image data. The optical microscope 9 outputs the acquired image data to the control device 100. The image data acquired by the optical microscope 9 is used, for example, to adjust the optical axis of the laser light LA ​​and to focus the optical microscope 9 on the observation object.

[0028] The optical microscope 9 is driven vertically in the Z-axis direction by a drive mechanism 90 consisting of a motion direction conversion mechanism configured by meshing a screw portion 91 formed on a member provided in the Z direction inside the case of the optical microscope 9 with a gear 92 coaxially attached to the motor shaft 11 of the second pulse motor 10. In the drive mechanism 90, the rotational motion of the motor shaft 11 is converted into the movement of the optical microscope 9 in the Z direction.

[0029] The control device 100 controls the operation of each component constituting the scanning probe microscope 1. The control device 100 is configured according to a general-purpose computer architecture, for example. The control device 100 may be implemented using hardware dedicated to the scanning probe microscope 1. The control device 100 includes a processor 101, a memory 102, a display unit 103, and an input unit 104. The control device 100 may also include the processor 101 and the memory 102, and the display unit 103 and the input unit 104 may be connected to the control device 100 as a display device and an input device not included in the control device 100.

[0030] The processor 101 is typically a CPU (Central Processing Unit) or an MP. The processor 101 is a processing unit such as a memory. The control device 100 reads out and executes the programs stored in 102 to realize each of the processes of the control device 100 described below. Note that, although the example of Fig. 2 illustrates a configuration in which there is a single processor, the control device 100 may have multiple processors.

[0031] The memory 102 is realized by a non-volatile memory such as a random access memory (RAM), a read only memory (ROM), and a flash memory. The memory 102 stores programs executed by the processor 101, data used by the processor 101, and the like. For example, the memory 102 stores various programs such as a program for executing the processes shown in FIG.

[0032] The memory 102 may be a compact disc-read only memory (CD-ROM), a digital versatile disc-read only memory (DVD-ROM), or a DVD-ROM, etc., as long as the memory 102 can non-temporarily record a program in a format readable by the control device 100, which is a type of computer. USB (Universal Serial Bus) memory, memory card, FD (Flexible Disk), hard disk, SSD (Solid State Drive), magnetic tape, cassette tape, MO (Magnetic Optical Disc), MD (Mini Disc), IC (Integrated Circuit) card (excluding memory cards), optical card, mask ROM, or EPROM.

[0033] The display unit 103 is configured with a liquid crystal display panel, etc. The display unit 103 displays, for example, the measurement results measured by the scanning probe microscope 1, or various setting screens for performing measurements by the scanning probe microscope 1, etc.

[0034] The input unit 104 is configured with a mouse, a keyboard, etc. The input unit 104 is an input interface that receives information input via the input unit 104. Note that the control device 100 may include a touch panel in which the display unit 103 and the input unit 104 are integrated.

[0035] The control device 100 sends a control signal to the drive circuit 31, which then supplies pulses corresponding to the control signal to the first pulse motor 8, thereby driving the first pulse motor 8. The control device 100 sends a control signal to the drive circuit 32, which then supplies pulses corresponding to the control signal to the second pulse motor 10, thereby driving the second pulse motor 10. The control device 100 sends a control signal to the drive circuit 33, which then applies a voltage corresponding to the control signal to the scanner 7, thereby driving the scanner 7.

[0036] The control device 100 sends a control signal to the drive device 30, which drives the motor in response to the control signal, thereby moving the laser light source 24. The control device 100 sends a control signal to the drive device 40, which drives the motor in response to the control signal, thereby moving the detector 23.

[0037] [Focus adjustment process for optical microscope 9] The focus adjustment process will be described with reference to Fig. 3. The focus adjustment process is a process for adjusting the focus of the optical microscope 9 on an observation object such as the cantilever 2.

[0038] 3 is a flowchart of the focus adjustment process. A program for executing the focus adjustment process is stored in the memory 102 of the control device 100, and is executed by the processor 101. In the following description, in order to make it easier to distinguish between the names of the pulses, the pulses supplied to the first pulse motor 8 may be referred to as first pulses, and the pulses supplied to the second pulse motor 10 may be referred to as second pulses.

[0039] The processor 101 executes the following processes in the focus adjustment process: In step S1, the processor 101 determines whether or not the current time is the initial focus setting time for adjusting the focus of the optical microscope 9.

[0040] When it is determined in step S1 that the focus is not being initially set, the processor 101 proceeds to step S4, which will be described later. On the other hand, when it is determined in step S1 that the focus is being initially set, the processor 101 executes the following process in step S2.

[0041] In step S2, while the head 4 is stopped, the processor 101 moves the optical microscope 9 from the initial position at a relatively slow first speed, and determines the position where the cantilever 2 is in focus based on the image obtained by the optical microscope 9, and then moves the optical microscope 9 slowly at a second speed slower than the first speed around the determined position, and determines the in-focus position based on the image obtained by the optical microscope 9, and determines the relative position where the focus was.

[0042] The "initial position" in step S2 is, for example, the position where the optical microscope 9 is farthest from the cantilever 2. The "position where the cantilever 2 is in focus" in step S2 is the position where the focus value, such as the contrast ratio, is maximized when comparing a pixel of the cantilever 2 with a pixel adjacent to that pixel in the peripheral image of the cantilever 2 obtained by the optical microscope 9. In other words, when the difference in data values ​​identifying adjacent pixels is greatest, it is determined that the optical microscope 9 is in focus based on the peripheral image of the cantilever 2 obtained by the optical microscope 9.

[0043] The “relative position” in step S 2 is the relative position between the position of the optical microscope 9 and the position of the cantilever 2 .

[0044] Next, in step S3, in order to specify the relative position between the focused optical microscope 9 and the cantilever 2, the processor 101 stores in the memory 102 first data as the number of second pulses supplied to the second pulse motor 10 to move the optical microscope 9 from the initial position during the initial focus setting, and second data as the number of first pulses supplied to the first pulse motor 8 to move the cantilever 2 from the initial position during the initial focus setting. During the initial focus setting in this case, the optical microscope 9 was moved with the head 4 stopped, so the second data is "0" since the number of first pulses supplied to the first pulse motor 8 was 0. During the initial focus setting, for example, if the number of second pulses supplied to the second pulse motor 10 from the initial position is 10, the data of 10 pulses is stored as the first data, and the data of 0 pulses is stored as the second data.

[0045] Next, in step S4, the processor 101 determines whether or not it is time for focus adjustment that can be performed after the above-mentioned focus initial setting is completed. Focus adjustment that is performed after the focus initial setting is completed refers to a case where, for example, in order to replace the cantilever 2 or to measure the sample S, the head 4 is moved up and down to move the cantilever 2 up and down while keeping the position of the optical microscope 9 fixed, causing the optical microscope 9 to lose focus on the cantilever 2, and an operation to adjust the focus is performed.

[0046] When it is determined in step S4 that the focus adjustment is not being performed, the processor 101 ends the process. On the other hand, when it is determined in step S4 that the focus adjustment is being performed, the processor 101 reads out from the memory 102 the stored data of the first data and the second data at the time of the initial focus setting, and further reads out from the memory 102 the stored data of the third data as the number of pulses supplied to the first pulse motor 8 and the fourth data as the number of second pulses supplied to the second pulse motor 10 during the operation of the head 4 that requires the focus adjustment, such as when the head 4 is moved up and down while the position of the optical microscope 9 is fixed to replace the cantilever 2 or to measure the sample S. In this way, the number of pulses supplied to the first pulse motor 8 and the second pulse motor 10 during the operation of the head 4 that requires the focus adjustment is obtained.

[0047] For example, when the head 4 is driven in an operational mode that requires focus adjustment, such as when the head 4 is moved up and down with the optical microscope 9 kept in a fixed position in order to replace the cantilever 2 or to measure the sample S, the processor 101 stores in the memory 102 third data as the number of first pulses supplied to the first pulse motor 8 and fourth data as the number of second pulses supplied to the second pulse motor, according to a program different from the program in Fig. 3. The data stored in the memory 102 when the head 4 is driven in an operational mode that requires focus adjustment is read out in step S5.

[0048] In this case, the third data is "0" because the head 4 was moved while the optical microscope 9 was stopped, and the number of second pulses supplied to the second pulse motor 10 was 0. For example, if the number of first pulses supplied to operate the head 4 when the head 4 is driven in an operating mode that requires focus adjustment is 20, the data of 20 pulses is stored as the third data, and the data of 0 pulses is stored as the fourth data.

[0049] In this manner, step S5 reads out the first data and second data stored in memory 102 in S3 during the initial focus setting, and further reads out data (third data) regarding the number of pulses of the first pulse supplied to the first pulse motor 8 when head 4 is operating and data (fourth data) regarding the number of pulses of the second pulse supplied to the second pulse motor 10 when head 4 is operating, which were stored in memory 102 during operation of head 4 when focus adjustment is required.

[0050] In step S6, based on the first data to fourth data read out in S5, the one-pulse operating amount of the first pulse motor 8, and the one-pulse operating amount of the second pulse motor 10, the processor 101 calculates a second number of pulses to be supplied to the second pulse motor 10 to move the optical microscope 9 to the relative position of the cantilever 2 and the optical microscope 9 that was focused during the initial focus setting, in order to focus the optical microscope 9 on the cantilever 2 again.

[0051] The “operation amount per pulse of the first pulse motor 8” in step S6 is the operation amount of the head 4 that operates when one pulse is supplied to the first pulse motor 8, i.e., the operation amount of the cantilever 2. The “operation amount per pulse of the second pulse motor 10” in step S6 is the operation amount of the optical microscope 9 that operates when one pulse is supplied to the second pulse motor 10.

[0052] In step S6, if the head 4 is driven in an operating mode that requires focus adjustment after the initial focus setting, the number of pulses to be supplied to the second pulse motor 10 is calculated to move the optical microscope 9 at a faster speed than during the initial focus setting until the relative positions of the cantilever 2 and the optical microscope 9 are in focus upon the cantilever 2 again.

[0053] In step S6, the number of pulses to be supplied to the second pulse motor 10 is calculated as follows: In the first data and second data read out in S5, the first data indicates the number of first pulses supplied to the first pulse motor 8 to move the cantilever 2 from its initial position during initial focus setting. The second data indicates the number of second pulses supplied to the second pulse motor 10 to move the optical microscope 9 from its initial position during initial focus setting.

[0054] The distance that the cantilever 2 has moved from its initial position at the time of the initial focus setting is calculated by multiplying the number of pulses of the first data by the amount of operation per pulse of the first pulse motor 8. The distance that the optical microscope 9 has moved from its initial position at the time of the initial focus setting is calculated by multiplying the number of pulses of the second data by the amount of operation per pulse of the second pulse motor 10. As an example, as described above, when the first data is "10 pulses", the second data is "0 pulses", the operation amount per pulse of the first pulse motor 8 is "0.2 (mm / pulse)", and the operation amount per pulse of the second pulse motor 10 is "0.1 (mm / pulse)", the distance that the cantilever 2 has moved from the initial position is calculated as 0 mm, and the distance that the optical microscope 9 has moved from the initial position is calculated as 2.0 mm. More specifically, in order to improve the measurement accuracy of the sample S, the first pulse motor 8 needs to bring the sample S and the cantilever 2 closer together in nm units. For this reason, in order to enable precise operation control, the operation amount per pulse of the first pulse motor 8 is set to, for example, a value on the order of nm. On the other hand, the operation amount per pulse of the second pulse motor 10 is set to a value on the order of μm, which is larger than that of the first pulse motor 8. In addition, a value within the range of, for example, 0.5 mm to 2.0 mm is generally used as the moving distance for adjusting the focus of the optical microscope 9.

[0055] The relative position between the initial position of the cantilever 2 and the initial position of the optical microscope 9 is stored in advance in the memory 102. Therefore, in step S6, the relative position (distance) between the optical microscope 9 and the cantilever 2 in a focused state at the time of initial focus setting can be obtained based on the number of pulses of the first data, the operation amount per pulse of the first pulse motor 8, the number of pulses of the second data, and the operation amount per pulse of the second pulse motor 10.

[0056] Multiplying the number of pulses of the third data by the amount of operation per pulse of the first pulse motor 8 calculates the distance the cantilever 2 has moved from the position at the time of the initial focus setting when the head 4 is driven in an operation mode that requires focus adjustment after the initial focus setting. Multiplying the number of pulses of the fourth data by the amount of operation per pulse of the second pulse motor 10 calculates the distance the optical microscope 9 has moved from the position at the time of the initial focus setting when the head 4 is driven in an operation mode that requires focus adjustment after the initial focus setting. As an example, as described above, when the third data is "20 pulses", the fourth data is "0 pulse", the amount of operation per pulse of the first pulse motor 8 is "0.2 (mm / pulse)", and the amount of operation per pulse of the second pulse motor 10 is "0.1 (mm / pulse), the distance the cantilever 2 has moved from the position at the initial focus setting is calculated to be 4.0 mm, and the distance the optical microscope 9 has moved from the position at the initial focus setting is calculated to be 0 mm.

[0057] In this way, in step S6, the relative position (distance) between the optical microscope 9 and the cantilever 2 when the head 4 is driven in an operating mode that requires focus adjustment can be determined based on the number of pulses of the third data, the one-pulse operation amount of the first pulse motor 8, the number of pulses of the fourth data, and the one-pulse operation amount of the second pulse motor 10.

[0058] Then, in step S6, based on the number of pulses of the third data, the amount of operation per pulse of the first pulse motor 8, the number of pulses of the fourth data, and the amount of operation per pulse of the second pulse motor 10, the number of second pulses of the second pulse motor 10 required to move the optical microscope 9 to the relative position (distance) between the optical microscope 9 and the cantilever 2 in a focused state at the time of initial focus setting is calculated from the relative position (distance) between the optical microscope 9 and the cantilever 2 when the head 4 is driven in an operating mode that requires focus adjustment, based on the number of pulses of the first data, the amount of operation per pulse of the first pulse motor 8, the number of pulses of the second data, and the amount of operation per pulse of the second pulse motor 10.

[0059] In such a calculation, for example, the difference between the relative position (distance) when the head 4 is driven in an operating mode that requires focus adjustment and the relative position (distance) at the time of initial focus setting is calculated, and the number of second pulses of the second pulse motor 10 required to move the optical microscope 9 until the calculated relative position (distance) difference becomes "0" is calculated based on the relative position (distance) difference and the one-pulse operating amount of the second pulse motor 10.

[0060] Next, in step S7, the processor 101 supplies second pulses, the number of which is calculated in step S6, to the second pulse motor 10, and executes control to move the optical microscope 9 at a third speed that is faster than the first speed at the initial focus setting, without determining the in-focus position based on the image obtained by the optical microscope 9. This allows the optical microscope 9 to be moved at a relatively high speed to a position where it is assumed that the cantilever 2 will be in focus.

[0061] Next, in step S8, after the movement of the optical microscope 9 in step S7 based on the number of pulses calculated in step S6 is completed, the processor 101 determines the focused position based on the image obtained by the optical microscope 9 while slowly moving the optical microscope 9 at the same speed as the second speed at the initial focus setting in the vicinity of the position after the movement. This makes it possible to execute a measurement that accurately determines the position at which the optical microscope 9 focuses on the cantilever 2 by image processing. In this way, in step S8, focus adjustment after the initial focus setting can be realized.

[0062] The focus adjustment process described in FIG. 3 can provide the following effects. Information such as the number of first pulses and the number of second pulses that can specify the relative position between the optical microscope 9 and the observation object such as the cantilever 2 in a focused state is stored, and when the optical microscope 9 is newly focused on the observation object, the optical microscope 9 is moved to the relative position in the focused state based on the stored information that can specify the relative position, and then the optical microscope 9 is controlled to move to the position where the optical microscope 9 is focused on the observation object while checking the focus. As a result, when the optical microscope 9 is newly focused on the observation object, it is not necessary to check the focus while moving the optical microscope 9 until the relative position between the optical microscope 9 and the observation object in the focused state is reached, so that the time required to focus the optical microscope 9 can be shortened. When the focus is not checked while moving the optical microscope 9, it is not necessary to execute various processes such as image processing for checking the focus, so that the optical microscope 9 can be moved at a high speed without waiting for the execution of various processes, compared to the case where the focus is checked while moving the optical microscope 9. Therefore, by being able to move the optical microscope 9 at such a high speed as the third speed, the time required for focusing the optical microscope 9 can be shortened.

[0063] [Modification of the embodiment] (1) In the above embodiment, an example was shown in which the object to be observed by the optical microscope 9 was a cantilever 2, but this is not limited to this, and the object to be observed by the optical microscope 9 may be an object other than a cantilever 2, such as a sample S.

[0064] (2) When the object to be observed by the optical microscope 9 is the sample S, the optical microscope 9 should be focused on the sample S.

[0065] (3) When the object to be observed by the optical microscope 9 is the sample S, the piezoelectric element of the scanner 7 is the drive source for the object to be observed.

[0066] (4) When the sample S is the object to be observed, the voltage applied from the drive circuit 33 may be used as information capable of identifying the relative position between the optical microscope 9 and the sample S.

[0067] (5) At least one of the driving mechanisms 50 and 90 may be a rack-and-pinion mechanism or another type of driving mechanism.

[0068] (6) The pulse motors such as the first pulse motor 8 and the second pulse motor 10 may be any type of motor as long as they are driven by receiving a supply of pulses such as a stepping motor.

[0069] (7) In the focus adjustment process of Fig. 3, an example has been described in which the optical microscope 9 is moved at the third speed relative to the cantilever 2 until it reaches the relative position determined to be in focus during the initial focus setting, and then a position where the focus is achieved in the vicinity of the position after the movement is determined and confirmed. However, the present invention is not limited to this, and the optical microscope 9 may be moved at the third speed to a position that is a predetermined distance (e.g., several mm) forward or backward from the relative position determined to be in focus during the initial focus setting, and then a position where the focus is achieved in the vicinity of the position after the movement, including the relative position determined to be in focus during the initial setting, may be determined and confirmed.

[0070] [Note] The scanning probe microscope of the present disclosure (scanning probe microscope 1) has the following features.

[0071] (1) A cantilever (cantilever 2) including a probe (probe 3) arranged to face a sample (sample S), an optical microscope (optical microscope 9) arranged at a position where an enlarged image of an observation target (cantilever 2 or sample S) in an observation target area including the cantilever (cantilever 2) and the sample (sample S) can be acquired, a first drive source (first pulse motor 8) that operates to move the observation target (cantilever 2), a second drive source (second pulse motor 10) that operates to move the optical microscope (optical microscope 9), and a control device (control device 100) that controls the first drive source (first pulse motor 8) and the second drive source (second pulse motor 10), and the control device (control device 100) controls the focus of the optical microscope (optical microscope 9) from an initial position to a position where the optical microscope (optical microscope 9) is focused on the observation target (cantilever 2 or sample S). The optical microscope (optical microscope 9) is moved while checking the focus (step S2), and information capable of identifying the relative position between the optical microscope (optical microscope 9) and the object being observed when in focus (data on the number of first pulses supplied and the number of second pulses supplied) is stored (step S3). When focusing the optical microscope (optical microscope 9) on a new object being observed (cantilever 2 or sample S), the optical microscope (optical microscope 9) is moved based on the stored information capable of identifying the relative position (data on the number of first pulses supplied and the number of second pulses supplied) (step S7), and then the optical microscope (optical microscope 9) is controlled to move while checking the focus until the optical microscope (optical microscope 9) is in focus with respect to the object being observed (cantilever 2 or sample S) (step S8).

[0072] According to this configuration, information (data on the number of first pulses supplied and the number of second pulses supplied) capable of identifying the relative position between the optical microscope (optical microscope 9) and the object to be observed (cantilever 2 or sample S) in a focused state is stored, and when the optical microscope (optical microscope 9) is to be focused on a new object to be observed (cantilever 2 or sample S), the optical microscope (optical microscope 9) is moved based on the stored information (data on the number of first pulses supplied and the number of second pulses supplied) capable of identifying the relative position until the optical microscope (optical microscope 9) is at the relative position in the focused state, and then the optical microscope (optical microscope 9) is controlled to move while checking the focus until the optical microscope (optical microscope 9) is focused on the object to be observed (cantilever 2 or sample S). As a result, when focusing the optical microscope (optical microscope 9) on a new object to be observed (cantilever 2 or sample S), there is no need to check the focus while moving the optical microscope (optical microscope 9) until the relative positions of the optical microscope (optical microscope 9) and the object to be observed (cantilever 2 or sample S) are in a focused state, thereby shortening the time required to focus the optical microscope (optical microscope 9).

[0073] (2) A cantilever (cantilever 2) including a probe (probe 3) arranged to face a sample (sample S), an optical microscope (optical microscope 9) arranged at a position where an enlarged image of the cantilever (cantilever 2) can be acquired, a first pulse motor (first pulse motor 8) that operates to move the cantilever (cantilever 2), a second pulse motor (second pulse motor 10) that operates to move the optical microscope (optical microscope 9), and a control device (control device 100) that controls the first pulse motor (first pulse motor 8) and the second pulse motor (second pulse motor 10), the control device (control device 100) being capable of controlling the cantilever (cantilever 2) to move from a first initial position by a moving distance corresponding to the number of first pulses supplied to the first pulse motor (first pulse motor 8), and the optical microscope (optical microscope 9) by a moving distance corresponding to the number of second pulses supplied to the second pulse motor (second pulse motor 10). It is possible to control the movement of the optical microscope (optical microscope 9) from the second initial position, and the optical microscope (optical microscope 9) is moved from the second initial position to a position where the optical microscope (optical microscope 9) is focused on the cantilever (cantilever 2) while checking the focus (step S2), and the number of first pulses and the number of second pulses that can specify the relative position of the optical microscope (optical microscope 9) and the cantilever (cantilever 2) in the focused state are stored (step S3). When newly focusing the optical microscope (optical microscope 9) on the cantilever (cantilever 2), the optical microscope (optical microscope 9) is moved until the relative position is reached based on the stored number of first pulses and the number of second pulses (step S7), and then the optical microscope (optical microscope 9) is controlled to be moved to a position where the optical microscope (optical microscope 9) is focused on the cantilever (cantilever 2) while checking the focus (step S8).

[0074] According to this configuration, the number of first pulses and the number of second pulses supplied that can identify the relative position between the optical microscope (optical microscope 9) and the cantilever (cantilever 2) in a focused state are stored, and when the optical microscope (optical microscope 9) is newly focused on the cantilever (cantilever 2), the optical microscope (optical microscope 9) is moved based on the stored number of first pulses and the number of second pulses supplied until the relative position is reached in the focused state, and then the optical microscope (optical microscope 9) is controlled to move to a position where the optical microscope (optical microscope 9) is focused on the cantilever (cantilever 2) while checking the focus. Therefore, when the optical microscope (optical microscope 9) is newly focused on the cantilever (cantilever 2), it is not necessary to check the focus while moving the optical microscope (optical microscope 9) until the relative position between the optical microscope (optical microscope 9) and the cantilever (cantilever 2) in the focused state, and therefore the time required to focus the optical microscope (optical microscope 9) can be shortened.

[0075] (3) The first pulse motor (first pulse motor 8) moves the cantilever (cantilever 2) a first distance each time a first pulse is supplied, and the second pulse motor (second pulse motor 10) moves the optical microscope (optical microscope 9) a second distance each time a second pulse is supplied.

[0076] With this configuration, the first pulse motor (first pulse motor 8) moves the cantilever (cantilever 2) a first distance each time a first pulse is supplied, and the second pulse motor (second pulse motor 10) moves the optical microscope (optical microscope 9) a second distance each time a second pulse is supplied, so that the relative position of the optical microscope (optical microscope 9) and the cantilever (cantilever 2) in a focused state can be determined based on the relationship between the number of first pulses supplied and the number of second pulses supplied.

[0077] (4) When moving the optical microscope (optical microscope 9) to the relative position of the optical microscope (optical microscope 9) and the cantilever (cantilever 2) in a focused state based on the stored number of first pulses and the stored number of second pulses, the control device (control device 100) sets the number of second pulses to be supplied to the second pulse motor (second pulse motor 10) based on the stored number of first pulses and the stored number of second pulses, a first distance the cantilever moves each time a first pulse is supplied, and a second distance the optical microscope (optical microscope 9) moves each time a second pulse is supplied (step S6).

[0078] According to this configuration, when the optical microscope (optical microscope 9) is moved until the relative position between the optical microscope (optical microscope 9) and the cantilever (cantilever 2) is in a focused state, the number of second pulses to be supplied to the second pulse motor (second pulse motor 10) is set based on the stored number of first pulses and the stored number of second pulses to be supplied, the first distance the cantilever moves each time a first pulse is supplied, and the second distance the optical microscope (optical microscope 9) moves each time a second pulse is supplied. Therefore, the amount of movement of the optical microscope (optical microscope 9) until the relative position between the optical microscope (optical microscope 9) and the cantilever (cantilever 2) is in a focused state can be determined by the number of second pulses to be supplied to the second pulse motor (second pulse motor 10).

[0079] (5) Further provided is a first driving mechanism (driving mechanism 50) for moving the cantilever (cantilever 2) and a second driving mechanism (driving mechanism 90) for moving the optical microscope (optical microscope 9), in which the first pulse motor (first pulse motor 8) moves the cantilever (cantilever 2) by the first driving mechanism (driving mechanism 50) each time a first pulse is supplied, and the second pulse motor (second pulse motor 10) moves the optical microscope (optical microscope 9) by the second driving mechanism (driving mechanism 90) each time a second pulse is supplied.

[0080] According to this configuration, the first pulse motor (first pulse motor 8) moves the cantilever (cantilever 2) via the first driving mechanism (driving mechanism 50) each time a first pulse is supplied, and the second pulse motor (second pulse motor 10) moves the optical microscope (optical microscope 9) via the second driving mechanism (driving mechanism 90) each time a second pulse is supplied. Therefore, the amount of movement of the objects to be driven, such as the cantilever (cantilever 2) and the optical microscope (optical microscope 9), can be easily set by the number of pulses supplied to pulse motors such as the first pulse motor (first pulse motor 8) and the second pulse motor (second pulse motor 10).

[0081] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0082] S sample, 3 probe, 2 cantilever, 9 optical microscope, 8 first pulse motor, 10 second pulse motor, 50, 90 driving mechanism, 1 scanning probe microscope.

Claims

1. A cantilever including a probe arranged facing the sample; an optical microscope arranged at a position capable of acquiring a magnified image of an object to be observed within an observation region including the cantilever and the sample; A first drive source that operates to move the observation object; A second drive source that operates to move the optical microscope; a control device for controlling the first drive source and the second drive source, The control device includes: moving the optical microscope at a first speed from an initial position to a position where the optical microscope is focused on the observation object while checking the focus, and storing information that enables identification of a relative position between the optical microscope and the observation object in the focused state; A scanning probe microscope that, when focusing the optical microscope on a new object to be observed, controls the optical microscope to move at a third speed faster than the first speed until the relative position is reached based on information capable of identifying the stored relative position, and then controls the optical microscope to move at a second speed slower than the first speed while checking the focus until the optical microscope is focused on the object to be observed.

2. A cantilever including a probe arranged facing the sample; an optical microscope arranged at a position where a magnified image of the cantilever can be obtained; A first pulse motor that operates to move the cantilever; A second pulse motor that operates to move the optical microscope; a control device for controlling the first pulse motor and the second pulse motor, The control device includes: It is possible to control the cantilever to move from a first initial position by a moving distance corresponding to the number of first pulses supplied to the first pulse motor, It is possible to control the optical microscope to move from the second initial position by a movement distance corresponding to the number of second pulses supplied to the second pulse motor, moving the optical microscope at a first speed from the second initial position to a position where the optical microscope is focused on the cantilever while checking the focus, and storing the number of first pulses and the number of second pulses that can specify the relative position between the optical microscope and the cantilever in the focused state; A scanning probe microscope that, when newly focusing the optical microscope on the cantilever, controls the optical microscope to move at a third speed faster than the first speed until the relative position is reached based on the stored number of first pulses supplied and the stored number of second pulses supplied, and then controls the optical microscope to move at a second speed slower than the first speed while checking the focus until the optical microscope is focused on the cantilever.

3. the first pulse motor moves the cantilever a first distance each time the first pulse is supplied, 3. The scanning probe microscope according to claim 2, wherein the second pulse motor moves the optical microscope a second distance each time the second pulse is supplied.

4. 4. The scanning probe microscope according to claim 2 or claim 3, wherein when the control device moves the optical microscope to the relative position based on the stored number of first pulses and the stored number of second pulses, the control device sets the number of second pulses to be supplied to the second pulse motor based on the stored number of first pulses and the stored number of second pulses, a first distance by which the cantilever moves each time the first pulse is supplied, and a second distance by which the optical microscope moves each time the second pulse is supplied.

5. A first drive mechanism that moves the cantilever; a second drive mechanism for moving the optical microscope; the first pulse motor moves the cantilever by the first drive mechanism every time the first pulse is supplied; 5. The scanning probe microscope according to claim 2, wherein the second pulse motor moves the optical microscope by means of the second drive mechanism every time the second pulse is supplied.

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