Scanning probe microscope and control method

Abstract

The detection mechanism (110) acquires first information indicating the position of the cantilever in the Z-axis direction and second information indicating the position of the sample (S) in the Z-axis direction or the position of the sample stage (14) in the Z-axis direction. The approach processing unit (104) determines a speed drop position on the basis of the first information and the second information. The approach processing unit (104) controls the displacement mechanism such that the approach speed changes from a high speed to a low speed at the speed-down position.

Description

Technical Field

[0001] The present disclosure relates to a scanning probe microscope and a control method. Background Art

[0002] The so-called optical lever scanning probe microscope (SPM) has a cantilever with a probe, a stage for placing a sample, and an optical microscope. The user can move the optical microscope independently of the cantilever and the stage. The user can use the optical microscope to visually observe the position of the sample and the probe.

[0003] The SPM can move the probe of the cantilever along the surface of the sample and acquire a concavo-convex image of the surface of the sample by detecting the deflection of the cantilever. This SPM also includes a light irradiation unit that irradiates light toward the cantilever and a light detection unit that receives reflected light from the cantilever.

[0004] When the SPM starts to observe the sample surface, it first performs an approach action to bring the cantilever close to the sample. Specifically, the approach action is an action to gradually bring the probe close to the sample surface by moving the cantilever vertically downward. In addition, the SPM moves the cantilever by performing feedback control based on the signal value represented by the detection signal from the light detection unit. Moreover, when the signal value reaches a preset target value, the SPM determines that the probe is close to the sample surface and stops the movement of the cantilever. Thus, the SPM ends the approach action and then observes the sample surface by scanning the cantilever in the horizontal direction.

[0005] In addition, Japanese Patent Gazette No. 2909828 (Patent Document 1) discloses a scanning tunneling microscope (STM) for measuring a sample. The STM has a probe, a workbench, and an optical microscope, but does not have a cantilever. The probe is fixed to the optical microscope. The sample is arranged on the workbench. In addition, the STM moves the workbench by feedback control based on the tunnel current.

[0006] When the STM starts observing the sample surface, it moves the stage on which the sample is placed in the thickness direction of the sample to perform an approaching operation to bring the probe close to the sample. When the probe and the sample are close, the STM starts measuring the sample.

[0007] STM sets the moving speed of the workbench to a high speed to shorten the time required for the approach action. However, when the moving speed of the workbench is set to a high speed, due to the implementation of the above-mentioned feedback control, there is a situation where the sample collides with the probe. Therefore, in the STM described in patent document 1, the distance between the sample and the probe is calculated, and the speed reduction position for reducing the speed of the workbench is determined based on the distance. Moreover, STM moves the workbench to the speed reduction position at a high speed, and when the workbench reaches the speed reduction position, the workbench is moved at a low speed.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent No. 2909828 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] SPM performs the above-mentioned feedback control in the approaching action. Therefore, strictly speaking, the cantilever stops in a manner later than the instruction to stop the cantilever issued by the control device, and there is a risk that the probe of the cantilever collides with the sample. Therefore, in the approaching action, it is considered to set the moving speed of the cantilever to a low speed to prevent the collision of the probe with the sample. However, if the moving speed of the cantilever is set to a low speed, the time required for the approaching action will increase.

[0013] In addition, it is considered to apply the technology of the STM for determining the speed drop position described in Patent Document 1 to the SPM. However, as mentioned above, in the STM, the probe is fixed relative to the optical microscope. On the other hand, in the SPM, as mentioned above, the optical microscope is moved independently of the cantilever and the workbench. Therefore, it is impossible to apply the technology of the STM in which the probe is fixed relative to the optical microscope to the SPM.

[0014] The present invention has been made to solve such a problem, and provides a scanning probe microscope and a control method that can reduce the risk of a cantilever contacting a sample surface and perform an approaching operation in a short time.

[0015] Solutions for solving problems

[0016] The scanning probe microscope disclosed in the present invention comprises: a sample stage, a cantilever, a displacement mechanism, a detection mechanism, and an approach processing unit. The sample stage is used to configure the sample. The cantilever scans along the surface of the sample. The displacement mechanism changes the relative position of the sample stage and the cantilever in the thickness direction of the sample. The detection mechanism obtains first information and second information, wherein the first information is information related to the position of the cantilever in the thickness direction, and the second information is information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The approach processing unit controls the displacement mechanism at a prescribed approach speed so that the sample stage and the cantilever are close. The approach processing unit determines a speed reduction position at which the approach speed is switched from a high speed to a low speed based on the first information and the second information. In addition, the approach processing unit controls the displacement mechanism so that the approach speed changes from a high speed to a low speed at the speed reduction position.

[0017] The control method disclosed in the present invention is a control method for a scanning probe microscope. The scanning probe microscope includes: a sample stage for configuring a sample; and a cantilever for scanning along the surface of the sample. The relative position of the sample stage and the cantilever in the thickness direction of the sample is changed. The control method includes the following processing: acquiring first information and second information, the first information being information related to the position of the cantilever in the thickness direction, and the second information being information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The control method includes the following processing: changing the relative position at a prescribed approach speed so that the sample stage and the cantilever are close. The control method includes the following processing: determining a speed reduction position for switching the approach speed from a high speed to a low speed based on the first information and the second information. Changing the relative position includes changing the relative position in such a way that the approach speed changes from a high speed to a low speed at the speed reduction position.

[0018] Effects of the Invention

[0019] According to the scanning probe microscope and the control method disclosed in the present invention, it is possible to reduce the risk of the cantilever contacting the sample surface and perform an approach operation in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a diagram schematically showing the structure of the SPM of the present disclosure.

[0021] Figure 2 It is a diagram showing a hardware configuration example of an information processing device.

[0022] Figure 3 This is a functional block diagram showing the main functions of the information processing device.

[0023] Figure 4 It is a diagram showing a method of determining a speed reduction position according to the first embodiment.

[0024] Figure 5 It is a diagram showing a method of determining a speed reduction position according to the first embodiment.

[0025] Figure 6 This is a flowchart showing the processing flow of the SPM according to the first embodiment.

[0026] Figure 7 It is a diagram showing an example of the mode setting screen according to the first embodiment.

[0027] Figure 8 This is an example of an input screen.

[0028] Fig. 9 It is a diagram showing a method of determining a speed reduction position according to the second embodiment.

[0029] Fig.10 It is a diagram showing a method of determining a speed reduction position according to the second embodiment.

[0030] Fig.11 This is a flowchart showing the processing flow of the SPM according to the second embodiment. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated.

[0032] <First Embodiment>

[0033] [Structure example]

[0034] Figure 1 1 is a diagram schematically showing the structure of a scanning probe microscope (SPM) involved in the present disclosure. The scanning probe microscope is also referred to as SPM 100. Typically, SPM 100 measures the shape of the surface of the sample S using a physical quantity acting between the probe 3 and the surface of the sample S. SPM 100 may also be an atomic force microscope (AFM). In this case, the physical quantity is an atomic force (attraction or repulsion).

[0035] like Figure 1As shown, the SPM 100 includes a measuring device 10, an information processing device 20, a display device 30, and an input device 40 as main components. The measuring device 10 includes an optical system 1, a cantilever 2, a micro-motion mechanism 12 (scanner), a sample stage 14, an XY direction drive unit 16, a Z direction drive unit 18, a feedback signal generating unit 22, a first motor 61, a second motor 62, and an optical microscope 50 as main components. In this embodiment, the first motor 61 and the second motor 62 are representatively stepping motors.

[0036] The surface of the sample stage 14 is the placement surface 14a. The sample S is placed on the placement surface 14a of the sample stage 14. Hereinafter, the thickness direction of the sample S is defined as the Z-axis direction, and the directions orthogonal to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. In addition, the Z-axis direction is also the height direction of the SPM 100.

[0037] The sample stage 14 is arranged on the micro-motion mechanism 12. The micro-motion mechanism 12 is a moving device for changing the relative position relationship between the sample S and the probe 3 during the analysis of the sample S. The micro-motion mechanism 12 includes an XY scanner 12xy and a Z scanner 12z. The XY scanner 12xy moves the sample stage 14 along the X-axis direction and the Y-axis direction. The Z scanner 12z makes micro-motions of the sample stage 14 along the Z-axis direction. The XY scanner 12xy has a piezoelectric element that is deformed according to the voltage applied from the XY direction drive unit 16. The Z scanner 12z has a piezoelectric element that is expanded and contracted according to the voltage applied from the Z direction drive unit 18. The Z scanner 12z is expanded and contracted by the piezoelectric element. In addition, the XY scanner 12xy and the Z scanner 12z are not limited to structures having piezoelectric elements.

[0038] The cantilever 2 is arranged to face the sample stage 14. The cantilever 2 is formed in a leaf spring shape, and one end of the cantilever 2 is supported by the bracket 4. In other words, the one end is a fixed end. In addition, the other end of the cantilever 2 is a free end, and is arranged to face the sample S on the sample stage 14. Figure 1 In the example shown, it is arranged above the Z-axis direction. The front end of the free end of the cantilever 2 has a surface and a back surface opposite to the surface. The surface is the surface facing the sample S. In addition, the probe 3 is arranged on the surface so as to face the sample S. During the analysis of the sample S, the cantilever 2 scans along the surface of the sample S.

[0039] In addition, a reflective member 2a for reflecting light is formed on the back of the cantilever 2. The reflective member 2a may be coated with a predetermined raw material (aluminum or metal, etc.). The front end of the free end of the cantilever 2 is displaced in the Z-axis direction by a physical quantity (e.g., atomic force) acting between the probe 3 and the sample S.

[0040] An optical system 1 for detecting the deflection amount (i.e., the displacement amount of the front end portion) of the cantilever 2 is provided above the cantilever 2 in the Z-axis direction. The optical system 1 irradiates the back surface (reflection member 2a) of the cantilever 2 with laser light when measuring the sample S, and detects the laser light reflected from the reflection surface. Specifically, the optical system 1 includes a laser light source 6, a beam splitter 5, a reflector 7, and a photodetector 8.

[0041] The laser source 6 has a laser oscillator that emits laser light. The photodetector 8 has a photodiode that detects the incident laser light. The laser light LA ​​emitted from the laser source 6 is reflected at the beam splitter 5 and irradiated to the reflective member 2a of the cantilever 2. The laser light reflected at the back surface of the cantilever 2 is further reflected at the reflective mirror 7 and is incident on the photodetector 8.

[0042] The photodetector 8 has a light receiving surface divided into a plurality of (for example, two) light receiving surfaces in the Z-axis direction (displacement direction) of the cantilever 2. Alternatively, the photodetector 8 has a light receiving surface divided into four in the Z-axis direction and the Y-axis direction. When the tip of the cantilever 2 is displaced in the Z-axis direction, the ratio of the amount of light irradiated to the plurality of light receiving surfaces changes, so the deflection amount (displacement amount) of the cantilever 2 can be detected based on the plurality of received light amounts.

[0043] In addition, the optical system 1 and the cantilever 2 constitute a "cantilever unit 35". The optical microscope 50 is arranged above the cantilever unit 35 in the Z-axis direction. The user focuses the optical microscope 50 on the sample S to determine the observation range, or focuses on the reflective member 2a of the cantilever 2 to adjust the irradiation position of the laser. The image data acquired by the optical microscope 50 is output to the information processing device 20.

[0044] The feedback signal generating unit 22 calculates the deflection amount of the cantilever 2 by performing arithmetic processing on the detection signal provided from the photodetector 8. The feedback signal generating unit 22 controls the Z-direction position of the sample S so that the atomic force between the probe 3 and the sample S is fixed. Below, this control is also referred to as "feedback control". Specifically, the feedback signal generating unit 22 calculates the deviation Sd between the calculated deflection amount of the cantilever 2 and the target value, and calculates the control amount for driving the Z scanner 12z so that the deviation Sd is zero. The feedback signal generating unit 22 calculates the voltage value Vz for shifting the Z scanner 12z based on the control amount. The feedback signal generating unit 22 outputs a voltage signal representing the voltage value Vz to the Z-direction driving unit 18. The Z-direction driving unit 18 applies the voltage value Vz to the Z scanner 12z. In this way, the Z-direction driving unit 18 accepts the input of the voltage value from the feedback signal generating unit 22, and applies a voltage based on the voltage value to the Z scanner 12z.

[0045] The information processing device 20 calculates the voltage value Vx in the X-axis direction and the voltage value Vy in the Y-axis direction for the XY-direction driving unit 16 so that the sample stage 14 moves relative to the probe 3 in the X-axis and Y-axis directions according to the preset scanning conditions, and outputs them to the XY-direction driving unit 16. The XY-direction driving unit 16 applies the voltage values ​​Vx and Vy to the XY scanner 12xy.

[0046] The information processing device 20 mainly controls the operation of the measuring device 10. The measurement data representing the feedback amount in the Z-axis direction (the applied voltage Vz and the deviation Sd for the Z scanner 12z) is output from the Z-direction driving unit 18 to the information processing device 20. The measurement data is sent to each measurement point determined at a predetermined interval in the Y-axis direction of the sample S. The information processing device 20 stores the measurement data. The information processing device 20 calculates the displacement of the sample S in the Z-axis direction according to the voltage Vz based on the relevant information stored in advance. The relevant information is information representing the relationship between the voltage Vz and the displacement of the sample S (sample stage 14) in the Z-axis direction corresponding to the voltage Vz.

[0047] The calculated displacement is a value reflecting a value indicating the position of the sample S in the Z-axis direction (hereinafter also referred to as a "Z value"). The information processing device 20 generates two-dimensional or three-dimensional measurement data indicating the shape of the surface of the sample S by calculating the displacement of the sample S in the Z-axis direction at each position in the X-axis and Y-axis directions within the scanning range.

[0048] The measurement data produced by the information processing device 20 includes a value (Z value) representing the position in the Z-axis direction at each position on the XY plane. In addition, the Z value is the height of the sample S at each position. In addition, for example, the position in the Z-axis direction is represented by a Z coordinate based on the origin. The origin in the Z-axis direction is, for example, the position of the configuration surface 14a when the sample stage 14 is present in the lowest position. In this way, the SPM 100 (information processing device 20) measures the surface state of the sample S based on the reflected light reflected by the reflective member 2a.

[0049] The display device 30 and the input device 40 are connected to the information processing device 20. The display device 30 is composed of, for example, a liquid crystal (LCD: Liquid Crystal Display) panel. The information processing device 20 displays information such as the shape of the surface of the sample S on the display device 30 based on the produced measurement data. In addition, the information processing device 20 displays the image data acquired by the optical microscope 50 and the input screen described later on the display device 30. In addition, the input device 40 is, for example, a pointing device such as a keyboard or a mouse, which is used to accept instructions from the user. When a touch panel is used as a user interface, the input device 40 is formed integrally with the display device 30. In addition, the information processing device 20 corresponds to the "control device" of the present disclosure.

[0050] The image data acquired by the optical microscope 50 through imaging is output to the information processing device 20. The information processing device 20 may also display the image data on the display device 30.

[0051] The user can determine the observation location by focusing the optical microscope 50 on the sample S, or adjust the laser irradiation position by focusing the optical microscope 50 on the cantilever 2. The cantilever 2 is disposed between the optical microscope 50 and the sample stage 14 in the Z-axis direction.

[0052] The cantilever unit 35 can be moved in the X-axis direction, the Y-axis direction, and the Z-axis direction by the driving force of the first motor 61. In addition, the information processing device 20 can control the first motor 61 by outputting a pulse signal to the first motor 61. And the information processing device 20 can determine the movement amount of the cantilever unit 35 based on the number of pulses of the pulse signal. The movement amount of the cantilever unit 35 is, for example, the movement amount from the initial position of the cantilever unit 35. In addition, the information processing device 20 can control the movement speed of the cantilever unit 35 (cantilever 2) by controlling the frequency of the pulse signal given to the first motor 61. For example, as described later, the information processing device 20 can move the cantilever unit 35 (cantilever 2) at high speed or low speed.

[0053] The first motor 61 has a lead screw for transmitting driving force to the cantilever unit 35. The information processing device 20 may determine the movement amount of the cantilever unit 35 as a value obtained by multiplying the pitch of the lead screw by the number of pulses applied.

[0054] In addition, the information processing device 20 can control the first motor 61 based on the user's command to the input device 40, thereby moving the cantilever unit 35. For example, when the user arranges the sample S on the sample stage 14, the user inputs a command for raising the cantilever unit 35 to the input device 40. As a result, the cantilever unit 35 rises and the space between the sample stage 14 and the cantilever 2 (probe 3) becomes larger, thereby facilitating the operation of arranging the sample S on the sample stage 14, and improving the convenience of the user.

[0055] In addition, the optical microscope 50 can be moved in the X-axis direction, the Y-axis direction, and the Z-axis direction by the driving force of the second motor 62. In addition, the information processing device 20 can control the second motor 62 by outputting a pulse signal to the second motor 62. And, the information processing device 20 can determine the movement amount of the optical microscope 50 and the position of the optical microscope 50 based on the number of pulses of the pulse signal. The movement amount of the optical microscope 50 is, for example, the movement amount from the initial position of the optical microscope 50. In addition, the second motor 62 has a lead screw for transmitting power to the optical microscope 50. The information processing device 20 can also determine the value obtained by multiplying the pitch of the lead screw by the number of pulses applied as the movement amount of the optical microscope 50.

[0056] Furthermore, the information processing device 20 can move the optical microscope 50 by controlling the second motor 62 based on a command from a user to the input device 40 .

[0057] [Hardware structure of information processing device]

[0058] Figure 2 2 is a diagram showing an example of the hardware configuration of the information processing device 20. Figure 2 The information processing device 20 has a CPU (Central Processing Unit) 160, a ROM (Read Only Memory) 162, a RAM (Random Access Memory) 164, a HDD (Hard Disk Drive) 166, a communication I / F (Interface) 168, a display I / F 170, an input I / F 172, and a motor I / F 174 as main components. Each component is connected to each other through a data bus. In addition, at least a part of the hardware structure of the information processing device 20 may also be inside the measuring device 10. Alternatively, the information processing device 20 may also be configured to be separated from the SPM 100 and configured to perform bidirectional communication with the SPM 100.

[0059] The communication I / F 168 acquires information (voltage value Vz and deviation Sd) from the Z-direction driving unit 18. In addition, the communication I / F 168 outputs the voltage value Vx and the voltage value Vy in the Y-axis direction to the XY-direction driving unit 16. In addition, the communication I / F 168 acquires image data from the optical microscope 50. The display I / F 170 is an interface for communicating with the display device 30. The input I / F 172 is an interface for communicating with the input device 40. In addition, the motor I / F 174 is an interface for outputting a pulse signal to the first motor 61 and the second motor 62.

[0060] ROM 162 stores programs executed by CPU 160. RAM 164 can temporarily store data generated by CPU 160 executing programs and data input via communication I / F 168. RAM 164 can function as a temporary data storage used as a work area. HDD 166 is a non-volatile storage device. A semiconductor storage device such as a flash memory may be used instead of HDD 166.

[0061] The program stored in ROM 162 may also be stored in a non-transitory storage medium and circulated as a program product. Alternatively, the program may also be provided by an information provider in the form of a product program that can be downloaded via the so-called Internet, etc. The information processing device 20 reads the program provided by a storage medium or the Internet, etc. The information processing device 20 stores the read program in a prescribed storage area (e.g., ROM 162). The CPU 160 can execute the image data acquisition process described later by executing the program. In addition, the information processing device 20 is also referred to as a "control device" or a "control circuit."

[0062] [Functional Configuration Example of Information Processing Device]

[0063] Figure 3 1 is a functional block diagram showing the main functions of the information processing device 20. The information processing device 20 has a detection unit 102, an approach processing unit 104, and a storage unit 108. In addition, the first motor 61 corresponds to the "displacement mechanism" of the present disclosure. The displacement mechanism changes the relative position of the sample stage 14 and the cantilever 2 (cantilever unit 35) in the Z-axis direction. The approach processing of the approach processing unit 104 will be described later. The detection mechanism 110 is composed of the optical microscope 50, the detection unit 102, and the second motor 62.

[0064] The number of pulses from the second motor 62 is input to the detection unit 102. The detection unit 102 acquires the first information and the second information based on the number of pulses of the second motor 62 as described later, and outputs the first information and the second information to the proximity processing unit 104. In this embodiment, the first information is information related to the position of the cantilever 2 in the Z-axis direction. In addition, the second information is information related to the position of the sample S in the Z-axis direction.

[0065] In addition, the detection unit 102 can detect the amount of movement of the cantilever 2 in the Z-axis direction based on the number of pulses from the first motor 61 .

[0066] The approach processing unit 104 controls the first motor 61 at an approach speed described later. Furthermore, the approach processing unit 104 determines a speed reduction position based on the first information and the second information. The speed reduction position is a position where the approach speed is switched from high speed to low speed. In addition, the approach processing unit 104 controls the first motor 61 so that the approach speed changes from high speed to low speed at the speed reduction position. The storage unit 108 stores a previous speed reduction position 108A described later. In addition, the storage unit 108 stores programs such as calculation formulas described later.

[0067] Data of an image captured by the optical microscope 50 (hereinafter also referred to as “image data”) is output from the optical microscope 50 to the detection unit 102. The detection unit 102 may detect whether the image data indicates that the object is in focus, as described later.

[0068] [Determination of speed reduction position]

[0069] Next, a method for determining the speed reduction position will be described. In the present embodiment, the focal length L3 of the optical microscope 50 is fixed at least during the period in which the approach process is performed.

[0070] When a predetermined start condition is satisfied, the SPM 100 starts measuring the sample S. The start condition includes the following first and second conditions. The first condition is satisfied when the user performs a start operation on the input device 40. The second condition is satisfied when the SPM 100 detects that the sample S to be measured has been placed.

[0071] As described above, in order to improve user convenience, the cantilever unit 35 including the cantilever 2 can be moved in the Z-axis direction according to the user's operation, etc. In particular, since the cantilever unit 35 is moved upward in order to place the sample S on the sample stage 14, there is a situation where the cantilever 2 (probe 3) and the sample S are greatly separated after the sample is placed. Therefore, when the above-mentioned starting conditions are met, the SPM 100 of this embodiment performs an approach process. The approach process is a process of bringing the cantilever 2 close to the sample S. The approach process is also referred to as an "approach action". In addition, the speed at which the cantilever 2 (cantilever unit 35) approaches the sample S during the approach process (approach period) is also referred to as an "approach speed".

[0072] More specifically, the approach process is a process of bringing the cantilever 2 close to the sample S while performing feedback control until the physical quantity (e.g., atomic force) received by the cantilever 2 from the sample S reaches a specified value. When the physical quantity reaches the specified value, the information processing device 20 outputs a stop command to the measuring device 10. The specified value may be set by the user or may be a predetermined value. In addition, in the approach process, instead of using the physical quantity, a value corresponding to the physical quantity (e.g., the deflection amount of the cantilever 2) may be used.

[0073] In the approach process of the present embodiment, the sample stage 14 is fixed, while the cantilever 2 is lowered. In addition, in the analysis of the sample S, the SPM 100 drives the sample stage 14 in the Z-axis direction by the Z-direction driving unit 18, and fixes the cantilever 2. In addition, as a modified example, in the analysis of the sample S, the SPM 100 may drive the cantilever 2 and fix the sample stage 14, or may drive both the cantilever 2 and the sample stage 14.

[0074] It is conceivable that the information processing device 20 sets the descent speed (approach speed) of the cantilever 2 to a high speed to shorten the approach processing time. However, when the descent speed of the cantilever 2 is too fast, even if the above-mentioned physical quantity reaches a specified value and the measuring device 10 receives a stop command from the information processing device 20, the cantilever 2 stops in a manner later than the reception of the stop command. Therefore, there is a risk of the cantilever 2 colliding with the sample S. In this case, at least one of the probe 3 and the sample S may be damaged. On the contrary, when the approach speed is slowed down in order to prevent the cantilever 2 from colliding with the sample S, the approach processing requires a lot of time.

[0075] Therefore, the SPM 100 of the present embodiment determines the speed reduction position in order to shorten the approach processing time and reduce the collision between the cantilever 2 and the sample S. In addition, the SPM 100 causes the cantilever unit 35 to drop to the speed reduction position at a first speed, and when reaching the speed reduction position, causes the cantilever unit 35 to drop at a second speed. Here, the second speed is a speed slower than the first speed. The first speed corresponds to the "high speed" of the present disclosure, and the second speed corresponds to the "low speed" of the present disclosure. For example, the first speed may be the maximum speed of the cantilever 2, and the second speed may be the minimum speed of the cantilever 2.

[0076] The SPM 100 lowers the cantilever 2 to the speed reduction position at high speed, thereby shortening the approach processing time. In addition, the cantilever 2 is lowered at a low speed after reaching the speed reduction position, thereby reducing the possibility of the cantilever 2 colliding with the sample S even if the cantilever 2 stops later than the stop command of the feedback control.

[0077] Figure 4 and Figure 5 This is a diagram for explaining a method of determining a speed reduction position according to the present embodiment. Figure 4 (A) is a diagram for explaining a method for obtaining the first information, Figure 4 (B) is a diagram for explaining a method for obtaining the second information. Figure 5 This is a diagram for explaining a method of determining a speed reduction position based on first information and second information.

[0078] First, the information processing device 20 lowers the optical microscope 50 and acquires image data from the optical microscope 50. The detection unit 102 of the information processing device 20 detects whether the object is in focus in the image data. If the detection unit 102 detects that the object is in focus, the position of the optical microscope 50 (the number of pulses of the second motor 62) at that time is stored.

[0079] In this embodiment, the information processing device 20 repeats this process twice, and recognizes the first focused position after the start of descent as information (first information) related to the position of the cantilever 2. Then, the information processing device 20 recognizes the second focused position as information (second information) related to the position of the sample S.

[0080] In addition, regarding the method of detecting whether the object is in focus, in this embodiment, a method is adopted in which the detection unit 102 processes the image data in real time and automatically performs the detection. As such a method, a conventionally known method can be appropriately adopted, for example, application of a contrast method, etc.

[0081] Specifically, use Figure 4 to explain. Figure 4(A) is a diagram showing a state where the optical microscope 50 starts to descend and focuses on the object for the first time, as detected by a predetermined method (e.g., the contrast method described above). The detection unit 102 obtains the number of pulses of the second motor 62 in this state as first information. The first information is information related to the position of the cantilever 2 (reflection member 2a) in the Z-axis direction.

[0082] When the detection unit 102 acquires the first information, the information processing device 20 performs a retraction process so that the detection light 50a from the optical microscope 50 does not irradiate the cantilever 2. The retraction process is, for example, a process of moving the cantilever 2 in at least one of the X-axis direction and the Y-axis direction. Thereafter, the information processing device 20 lowers the optical microscope 50 until the focus is on the object again.

[0083] Figure 4 (B) is a diagram showing a state where the focus is first aligned with the object after the retraction process is performed by a predetermined method. The detection unit 102 obtains the number of pulses of the second motor 62 at this time point as the second information. The second information is information related to the position of the sample S (sample surface Sa) in the Z-axis direction. As described above, the detection unit 102 (detection mechanism 110) obtains the first information and the second information based on the detection of the optical microscope 50.

[0084] Here, in Figure 4 In the state (A), the distance between the lens of the optical microscope 50 and the reflective member 2a of the cantilever 2 should be the focal length L3 of the optical microscope 50. Figure 4 In the state (B), the distance between the lens of the optical microscope 50 and the reflective member 2a of the sample surface Sa should be the focal length L3 of the optical microscope 50. Since the distance L3 is fixed, Figure 4 As shown in (A), the distance L1 is the same as the distance L2. The distance L1 is the distance that the optical microscope 50 is lowered (refer to Figure 4 (B)). The distance L2 is the distance from the reflective member 2a (more precisely, the portion of the reflective member 2a irradiated with the detection light) to the sample surface Sa. In other words, the distance L2 is the distance between the cantilever 2 and the sample S.

[0085] In this way, the proximity processing unit 104 can calculate the distance L2 based on the difference between the "first information (the number of pulses of the second motor 62 in the state where the cantilever is focused)" and the "second information (the number of pulses of the second motor 62 in the state where the sample surface is focused)". For example, the proximity processing unit 104 can calculate the distance L2 by subtracting the "second information" from the "first information" and converting the number of pulses into a movement amount.

[0086] The proximity processing unit 104 determines the speed reduction position α based on the calculated distance L2. Figure 5 Let's explain in detail.

[0087] The distance L4 from the reflective member 2a to the front end 3a of the probe 3 is a fixed value determined according to the type of cantilever used. In addition, the fixed distance from the sample surface Sa is set to distance L6. Distance L6 is a distance at which the cantilever 2 is closer to the sample as the possibility that the physical quantity received from the sample S reaches a specified value is greater, and is a fixed value determined by the user according to the properties and shape of the sample S. In other words, it is the distance between the sample and the cantilever at which it is desired to start to reduce the approach speed, for example, 0.5 mm. In addition, it is also possible that distance L4 and distance L6 can be changed by the user.

[0088] The proximity processing unit 104 calculates the distance L5 between the tip 3a of the probe and the sample surface Sa by subtracting the distance L4 from the distance L2. Furthermore, the proximity processing unit 104 calculates the distance L7 for the cantilever to be moved at a high speed by subtracting the distance L6 from the distance L5. That is, the proximity processing unit 104 calculates the distance L7 by the following formula (1).

[0089] L7=L2-L4-L6 (1)

[0090] Here, the distance L2 on the right side of the formula (1) is the same as the distance L1 which is the descending distance of the optical microscope 50. In addition, the distance L4 and the distance L6 on the right side of the formula (1) are fixed values. Therefore, the total value M of the distance L4 and the distance L6 is also a fixed value. That is, the distance L7 can also be expressed by the following formula (2).

[0091] L7=L1-M1 (2)

[0092] In this way, the proximity processing unit 104 can calculate the distance L5 between the front end 3a of the probe and the sample surface Sa based on the first information and the second information. And, the distance L7 for moving the cantilever at high speed can be calculated based on the distance L5 and the fixed value stored in advance. That is, the speed reduction position α that reduces the approach speed of the cantilever 2 (cantilever unit 35) can be determined. And, the proximity processing unit 104 controls the first motor 61 so that the cantilever 2 approaches the sample S and the approach speed is reduced at the speed reduction position α.

[0093] That is, the proximity processing unit 104 makes the Figure 5The cantilever 2 (the position of the cantilever 2 shown in the figure) moves a distance L7 at a first speed (high speed). It is assumed that the cantilever 2 reaches the speed reduction position α after moving an amount corresponding to the distance L7, thereby changing the approach speed of the cantilever 2 to the second speed (low speed). Then, the cantilever 2 is further moved until the physical quantity received from the sample S reaches a specified value. Through this control, the cantilever 2 can move from the initial position to the speed reduction position α at a high speed, and move at a low speed from the speed reduction position α. ​​As a result, the SPM 100 can reduce the risk of the cantilever 2 contacting the sample surface Sa and perform the approach action in a short time.

[0094] The separation distance L6 between the speed reduction position α and the sample surface is a fixed value, while the separation distance L7 from the tip 3a of the probe varies according to the height of the cantilever 2 at every moment, so the separation distance L7 cannot be grasped in the prior art. Even if the absolute value of the height of the cantilever 2 can be identified, the height of the sample surface is unknown, so the distance L7 still cannot be grasped.

[0095] In this embodiment, the distance L7 can be grasped based on the first information and the second information calculated by the optical microscope 50. Note that it is not necessary to calculate the separation distance between the sample surface and the cantilever 2 and the absolute values ​​of the sample surface and the cantilever height.

[0096] In the present embodiment, the second information is information indicating the position of the sample surface Sa in the Z-axis direction. Therefore, the information processing device 20 can acquire the second information by detecting the sample surface Sa through the detection mechanism 110 .

[0097] In addition, the focal length L3 of the optical microscope 50 is fixed at least during the period of executing the proximity processing. Therefore, compared with a configuration in which the focal length L3 of the optical microscope 50 is variable, the processing load of the optical microscope 50 can be reduced.

[0098] In addition, in this embodiment, the reflective member 2a of the cantilever 2 for measuring the sample can also be used as the reflective member 2a for acquiring the first information. Therefore, compared with an SPM in which the reflective member for measuring the sample and the reflective member for acquiring the first information are different, the SPM 100 of this embodiment can reduce the number of components.

[0099] In addition, in the present embodiment, the optical microscope 50 that can display image data for a period other than the approach period can also be used as the optical microscope 50 for acquiring the first information and the second information. Therefore, compared with the SPM in which the optical microscope that displays the detection image is different from the optical microscope that is used to acquire the first information and the second information, the scanning probe microscope disclosed in the present invention can reduce the number of components.

[0100] [flow chart]

[0101] Figure 6 1 is a flowchart showing the processing flow of the SPM 100 according to the present embodiment. Figure 6 First, in step S102, the SPM 100 acquires first information (information related to the position of the cantilever in the Z-axis direction) (refer to Figure 4 (A)).

[0102] Next, in step S104, the SPM 100 acquires second information (information related to the position of the sample surface Sa in the Z-axis direction) (refer to Figure 4 Next, in step S106, the SPM 100 determines the speed reduction position α (refer to Figure 5 ). Next, in step S108, the SPM 100 performs an approach process based on the speed reduction position α. ​​Then, when the approach process is completed, the SPM 100 starts measuring the sample S in step S110.

[0103] [Last speed drop position]

[0104] Next, explain Figure 3 The last speed drop position 108A. The thickness of the sample S measured this time is sometimes the same as or approximately the same as the thickness of the sample S measured last time. In this case, the speed drop position α is the same in the last measurement and this measurement. Therefore, when the user recognizes that the thickness of the sample S measured this time is the same as or approximately the same as the thickness of the sample S measured last time, it is preferred that the information processing device 20 use the speed drop position α determined last time as the speed drop position α in this measurement.

[0105] When the speed reduction position α is determined, the information processing device 20 stores the speed reduction position α as the previous speed reduction position 108A. Furthermore, the user can select whether to use the previous speed reduction position 108A as the current speed reduction position.

[0106] Figure 7 is a diagram showing an example of a mode setting screen. When the above-mentioned start condition is satisfied, the mode setting screen is displayed in the display area 30A of the display device 30. Figure 7 In the example of , the modes of SPM 100 include a normal mode and a same mode as last time. Figure 7 In the example of FIG. 4 , a character image 41 of the normal mode, a character image 43 of the same mode as last time, and an OK button 44 are displayed.

[0107] Users pass through Figure 7By entering a command on the mode setting screen, you can select (set) the desired mode. Figure 7 In the example of , when a radio button corresponding to a desired mode is selected and the OK button 44 is operated, the mode is set. The setting of the mode is realized by storing a mode flag indicating the mode in a predetermined storage area, for example.

[0108] When the user sets the normal mode, the information processing device 20 Figure 6 The speed reduction position α is determined by the processing of . The case where the user sets the same mode as last time is described.

[0109] The information processing device 20 stores in advance the distance (a value obtained by converting the number of pulses of the first motor into a distance) by which the user raised the cantilever 2 after the last measurement. Since this distance corresponds to L5 (the current separation distance between the cantilever tip and the sample surface), the distance L7 can be calculated by subtracting the last used L6 from L5.

[0110] According to such a configuration, the cantilever 2 can be moved based on the speed drop position determined last time, and therefore, the process of dropping the optical microscope 50 and the process of image data acquired by the optical microscope 50 can be reduced.

[0111] <Second Embodiment>

[0112] Next, the second embodiment is described. For example, the sample S sometimes has a characteristic that the optical microscope 50 cannot be focused. This characteristic refers to a characteristic that the sample surface Sa is black and does not have a certain degree of contrast. In such a case, it is sometimes impossible to focus the optical microscope 50 on the sample S, and the speed reduction position α cannot be determined. Therefore, in the second embodiment, a structure is described in which the speed reduction position α can be determined even when the optical microscope 50 cannot be focused on the sample S.

[0113] The configuration surface 14a of the second embodiment is a reflective component. The reflective component is, for example, a reflector. As such, the configuration surface 14a is a reflective component, and thus, the SPM 100 can focus the optical microscope 50 on the configuration surface 14a. Therefore, the detection mechanism 110 can obtain the position of the configuration surface 14a in the Z-axis direction as the second information.

[0114] That is, in the second embodiment, the information processing device 20 identifies the position of the object at which the optical microscope 50 is focused for the first time after the start of descent as the position of the cantilever 2 (first information), and identifies the position of the object at which the optical microscope 50 is focused for the second time as the position of the configuration surface 14a (second information).

[0115] In addition, when the sample S is present at the focus position of the optical microscope 50, the detection mechanism 110 cannot detect the configuration surface 14a due to being blocked by the sample S. Therefore, in the second embodiment, the SPM100 performs a prescribed process for the detection mechanism 110 to detect the position of the configuration surface 14a. The prescribed process of this embodiment is, for example, a process of moving the sample stage 14 a prescribed distance in a prescribed direction on the XY plane. According to this process, the sample S can be retreated, and as a result, the detection mechanism 110 can detect the configuration surface 14a (the second information can be obtained). This prescribed process is also referred to as "retreat process of sample S". In addition, when the configuration surface 14a is detected, the SPM 100 moves the sample stage 14 so that the sample S returns to its original position.

[0116] Furthermore, in the present embodiment, in order to determine the speed reduction position α, the thickness of the sample S is used. The thickness of the sample S is input by the user, for example. Figure 8 This is an example of an input screen for inputting the thickness of a sample. For example, when the above-mentioned start condition is satisfied, this input screen is displayed in the display area 30A of the display device 30. Figure 8 In the example of FIG. 4 , an input area 45 is displayed. The user inputs the thickness of the sample in the input area 45 .

[0117] Fig. 9 and Fig.10 is a diagram for explaining the method of determining the speed reduction position of the present embodiment. Fig. 9 and Fig.10 , the state after the retreat process of the sample S is executed is shown. Fig. 9 In (A), Figure 4 (A) similarly shows that the information processing device 20 acquires the first information (information related to the position of the cantilever 2 in the Z-axis direction). Fig. 9 (B) shows that the information processing device 20 acquires the second information (information related to the position of the arrangement surface 14 a in the Z-axis direction).

[0118] In addition, Fig. 9 (A) and Fig. 9 In (B), the distance L3 (the focal length of the optical microscope 50) is fixed. Fig. 9 As shown in (A), the distance L11 is the same as the distance L12. The distance L11 is the distance that the optical microscope 50 is lowered (refer to Fig. 9 (B)). The distance L12 is the distance from the reflective member 2a (more precisely, the portion of the reflective member 2a irradiated with the detection light) to the arrangement surface 14a. In other words, the distance L12 is the distance between the cantilever 2 and the arrangement surface 14a.

[0119] In addition, if Fig.10As shown, the proximity processing unit 104 determines the speed reduction position α based on the distance L12. Fig.10 As shown in FIG. 1 , the thickness of the sample is set to a distance L18. Here, the thickness of the sample (distance L18) is set by the user in advance. Figure 8 The input value entered in the input screen.

[0120] The proximity processing unit 104 calculates the distance L15 by subtracting the distance L4 from the distance L12. The distance L15 is the distance between the tip 3a of the probe and the configuration surface 14a. Furthermore, the proximity processing unit 104 calculates the distance L17 by subtracting the distance L6 and the distance L18 from the distance L15. That is, the proximity processing unit 104 calculates the distance L17 by the following formula (3).

[0121] L17=L12-L4-L6-L18 (3)

[0122] Here, the distance L12 on the right side of the equation (3) is the same as the distance L11 which is the descending distance of the optical microscope 50. The distance L4 and the distance L6 on the right side of the equation (3) are the above-mentioned total value M. That is, the distance L17 can also be expressed by the following equation (4).

[0123] L17=L11-L18-M1 (4)

[0124] Fig.11 2 is a flowchart showing the processing flow of the information processing device 20 of this embodiment. Fig.11 in Figure 6 The processing of step S120 and step S122 is added before step S102, and step S104 is replaced by step S124.

[0125] When the above-mentioned start condition is satisfied, in step S120, the information processing device 20 executes the evacuation process of the sample S. Next, in step S122, the information processing device 20 obtains the thickness of the sample S input by the user (refer to Figure 8 ).

[0126] Then, after the process of step S102 is completed, in step S124, the information processing device 20 acquires the second information (the position of the sample stage 14 in the Z-axis direction) Thereafter, the information processing device 20 executes the process of step S106.

[0127] As described above, even if the sample S has a characteristic that the optical microscope 50 cannot focus on the sample S, the information processing device 20 of this embodiment can determine the speed reduction position α based on the first information, the second information, and the thickness of the sample (distance L18).

[0128] In addition, the information processing device 20 executes an evacuation process (predetermined process) of the sample S (step S120 ). Therefore, even if the sample S is present at a position that prevents the information processing device 20 from acquiring the second information, the information processing device 20 can acquire the second information.

[0129] The sample S evacuation process is a process of moving the sample stage 14 on the XY plane. Therefore, the SPM 100 can realize the sample S evacuation process by a relatively simple process.

[0130] <Modification>

[0131] (1) In the above-mentioned embodiment, the structure in which the SPM 100 moves (descends) the cantilever 2 without moving the sample stage 14 (fixing the sample stage 14) during the approach process is described. However, in the approach process, a structure in which the sample stage 14 is moved (raised) without moving the cantilever 2 (fixing the cantilever 2) may be adopted. In the case of this structure, the SPM 100 determines the speed reduction position α based on the distance L2 or the distance L12, etc. Then, the SPM 100 moves (raises) the sample stage 14 to the speed reduction position α at the third speed, and moves (raises) the sample stage 14 at the fourth speed (a speed slower than the third speed) from the time when the sample stage 14 reaches the speed reduction position α.

[0132] In addition, the SPM 100 may also perform the movement (descent) of the cantilever 2 and the movement (ascent) of the sample stage 14 during the approach process. In this case, the speed reduction position of the cantilever 2 (hereinafter referred to as the "first speed reduction position α1") and the speed reduction position of the sample stage 14 (hereinafter referred to as the "second speed reduction position α2") are determined based on the distance L2 or the distance L12, etc. Then, during the approach process, the SPM 100 moves (descends) the cantilever 2 to the first speed reduction position α1 at the first speed, and moves (descends) the sample stage 14 at the second speed from the time when the cantilever 2 reaches the first speed reduction position α1. In addition, the SPM 100 moves (ascends) the sample stage 14 to the second speed reduction position α2 at the third speed, and moves (ascends) the sample stage 14 at the fourth speed from the time when the sample stage 14 reaches the second speed reduction position α2. That is, the first motor 61 is a displacement mechanism that changes the relative position of the sample stage 14 and the cantilever 2 in the Z-axis direction. The above-mentioned approach speed is the speed of change of the relative position. Even an SPM having such a structure can achieve the same effects as the above-mentioned SPM.

[0133] (2) In the above-mentioned embodiment, the first information is described as the position of the reflective member 2a of the cantilever 2 in the Z-axis direction. However, the first information may be any part of the cantilever 2 or another part. For example, the first information may be the position of the probe 3 in the Z-axis direction.

[0134] (3) In the above-mentioned embodiment, the optical microscope 50 is exemplified as the detection device for detecting the first information and the second information. However, the detection device may be other devices. For example, the other device may be a camera or a microscope associated with the optical microscope 50 (for example, an electron microscope).

[0135] (4) In addition, in the above-mentioned embodiment, a structure in which the focal length of the optical microscope 50 is fixed during the approach is described. However, as long as the approach processing unit 104 can identify the focal length of the optical microscope 50, it can also be set to be variable. In the case of adopting such a structure, for example, the first information and the second information can also be identified by changing the focal length. That is, the focal length of the optical microscope 50 is changed in stages in a lengthening manner, and the focal length at the first focusing is identified as L3. The focal length at the second focusing is identified as L1+L3. By subtracting them, the distance L2 (=L1) between the cantilever 2 and the sample surface can be identified.

[0136] When such a configuration is adopted, the information processing device 20 can acquire the first information and the second information, for example, in a state where the optical microscope 50 is fixed. Therefore, the process of moving the optical microscope 50 can be reduced.

[0137] In addition, after the optical microscope 50 acquires the first information, the focal length for acquiring the second information can be calculated by adding a predetermined value to the focal length when the first information is acquired. The information processing device 20 determines whether the second information can be acquired based on the calculated new focal length. Moreover, when the information processing device 20 is not focused and cannot acquire the second information, it acquires the second information by driving the optical microscope 50. In the case of such a structure, the moving distance of the optical microscope 50 can be reduced.

[0138] (5) In the above-mentioned embodiment, a structure in which the optical microscope 50 is automatically focused is described. However, a structure in which the user manually focuses the optical microscope 50 may also be adopted. For example, the information processing device 20 may detect at least one of the position of the cantilever 2 in the Z-axis direction, the position of the sample surface Sa in the Z-axis direction, and the position of the configuration surface 14a in the Z-axis direction by focusing manually performed by the user.

[0139] (6) In the above-mentioned embodiment, the predetermined process for the detection mechanism 110 to acquire the second information is described as a process of moving the sample stage 14 to cause the sample S to retreat (see Fig.11 However, the predetermined processing may be other processing. For example, the predetermined processing may be processing for moving the optical microscope 50 by a predetermined distance in a predetermined direction on the XY plane.

[0140] Alternatively, the optical microscope 50 may be lowered until the structure (sample stage) inside the cantilever 2 is in focus while the cantilever 2 is in the field of view. In this case, the SPM 100 does not need to retract the cantilever 2 .

[0141] Alternatively, the speed reduction position α may be determined before configuring the sample S having the above-mentioned characteristics. For example, the information processing device 20 lowers the optical microscope 50 before configuring the sample S. Then, the object that is focused on for the first time after the optical microscope 50 starts to descend is identified as the position of the cantilever 2 (first information), and the object that is focused on for the second time is identified as the position of the sample S (second information). Then, the information processing device 20 displays the position of the sample S. Figure 8 The information processing device 20 uses the input screen to obtain the thickness of the sample S. The information processing device 20 determines the speed reduction position α based on the first information, the second information and the thickness of the sample S. After determining the speed reduction position α, the information processing device 20 executes a prompting notification to prompt the sample S to be placed on the sample table 14. The prompting notification is, for example, a process of displaying a text image such as "Please place the sample" on the display device 30. When the sample S is placed and the user starts the operation, the information processing device 20 executes an approach process. According to such a structure, the speed reduction position α can be determined without performing a prescribed process.

[0142] (7) Figure 4 and Fig. 9 In the example of FIG. 5 , the optical microscope 50 is simplified by a rectangle. Figure 4 and Fig. 9 In the example, the distance between the optical microscope 50 and the detection object (the reflective component 2a of the cantilever 2, the sample surface Sa) is set to the distance between the lower side of the rectangle and the detection object. However, the distance may also be the distance between a predetermined component of the optical microscope 50 and the detection object. The predetermined component may also be, for example, an optical system (lens) etc. possessed by the optical microscope 50.

[0143] [Way]

[0144] It will be understood by those skilled in the art that the above-mentioned multiple exemplary embodiments are specific examples of the following aspects.

[0145] (Item 1) The scanning probe microscope disclosed in the present invention comprises: a sample stage, a cantilever, a displacement mechanism, a detection mechanism, and an approach processing unit. The sample stage is used to configure the sample. The cantilever scans along the surface of the sample. The displacement mechanism changes the relative position of the sample stage and the cantilever in the thickness direction of the sample. The detection mechanism obtains first information and second information, wherein the first information is information related to the position of the cantilever in the thickness direction, and the second information is information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The approach processing unit controls the displacement mechanism at a prescribed approach speed so that the sample stage and the cantilever are close. The approach processing unit determines a speed reduction position at which the approach speed is switched from a high speed to a low speed based on the first information and the second information. In addition, the approach processing unit controls the displacement mechanism so that the approach speed changes from a high speed to a low speed at the speed reduction position.

[0146] According to such a structure, the scanning probe microscope detects not only the second information as the position of the sample or the position of the sample stage, but also the first information of the cantilever. Then, the scanning probe microscope can determine the speed drop position for switching the approach speed from high speed to low speed based on the first information and the second information. Therefore, even if the cantilever can move in the thickness direction of the sample, the drop position can be appropriately determined, so that the danger of the cantilever contacting the sample surface can be reduced and the approach action can be performed in a short time.

[0147] (Item 2) The scanning probe microscope according to Item 1, wherein the second information is information indicating a position of a surface of the sample in a thickness direction.

[0148] According to such a configuration, the detection mechanism can detect the second information by detecting the surface of the sample.

[0149] (Item 3) A scanning probe microscope according to Item 1, wherein the sample stage has a configuration surface on which the sample is configured. The second information is information indicating the position of the configuration surface in the thickness direction. The proximity processing unit receives input of thickness information indicating the thickness of the sample from a user. The proximity processing unit determines the speed reduction position based on the first information, the second information, and the thickness information.

[0150] According to such a configuration, the second information can be acquired even when the detection mechanism cannot detect the surface of the sample.

[0151] (Item 4) The scanning probe microscope according to Item 3, wherein the scanning probe microscope executes a predetermined process for the detection mechanism to acquire the second information. After executing the predetermined process, the detection mechanism acquires the second information.

[0152] According to such a configuration, even when the detection mechanism cannot obtain the information due to, for example, obstruction by the sample, the second information indicating the position of the arrangement surface can be obtained by executing a predetermined process.

[0153] (Item 5) A scanning probe microscope according to Item 4, wherein the predetermined processing includes a processing of moving the sample stage.

[0154] According to such a configuration, the second information can be acquired through a relatively simple process of moving the sample stage.

[0155] (Item 6) A scanning probe microscope according to any one of Items 1 to 5, wherein the detection mechanism includes an optical microscope with a fixed focal length. The cantilever is arranged between the optical microscope and the sample stage in the thickness direction. The scanning probe microscope moves the optical microscope in the thickness direction. The detection mechanism obtains first information based on the position of the optical microscope at a distance between the cantilever and the optical microscope being the focal length. The detection mechanism obtains second information based on the position of the optical microscope at a distance between the sample or the sample stage and the optical microscope being the focal length.

[0156] According to such a configuration, the first information and the second information can be acquired using a microscope having a relatively simple configuration.

[0157] (Item 7) A scanning probe microscope according to Item 6, wherein a reflective member is formed on the cantilever on the opposite side of the portion facing the sample. The cantilever is displaced in such a manner that a physical quantity acting between the cantilever and the sample is fixed. The scanning probe microscope further comprises a light source, which irradiates light to the reflective member. The scanning probe microscope measures the sample based on reflected light reflected from the reflective member. The detection mechanism acquires the first information based on the position of the optical microscope at which the distance between the reflective member and the optical microscope is the focal length.

[0158] According to such a structure, the reflective member for measuring the sample can be used as the reflective member for acquiring the first information. Therefore, compared with a scanning probe microscope in which the reflective member for measuring the sample and the reflective member for acquiring the first information are different, the scanning probe microscope disclosed in the present invention can reduce the number of components.

[0159] (Item 8) A scanning probe microscope according to any one of Items 1 to 5, wherein the scanning probe microscope further comprises a storage device that stores a speed reduction position determined last time. The approach processing unit controls the displacement mechanism so that the approach speed changes from a high speed to a low speed at the speed reduction position last stored in the storage device.

[0160] According to such a configuration, the displacement mechanism can be controlled based on the speed reduction position determined in advance, and therefore, the processing for determining the speed reduction position can be reduced.

[0161] (Item 9) The scanning probe microscope according to any one of Items 1 to 5, wherein the proximity processing unit performs feedback control until a physical quantity acting between the cantilever and the sample reaches a predetermined quantity, thereby controlling the displacement mechanism.

[0162] According to such a configuration, the displacement mechanism can be controlled by a relatively simple process.

[0163] (Item 10) The scanning probe microscope according to any one of Items 1 to 5, wherein the cantilever moves in the thickness direction independently of the sample stage.

[0164] According to such a configuration, it is possible to improve the convenience for the user when placing a sample on the sample stand or the like.

[0165] (Item 11) The control method disclosed in the present invention is a control method for a scanning probe microscope. The scanning probe microscope includes: a sample stage for configuring a sample; and a cantilever for scanning along the surface of the sample. The relative position of the sample stage and the cantilever in the thickness direction of the sample is changed. The control method includes the following processing: acquiring first information and second information, the first information being information related to the position of the cantilever in the thickness direction, and the second information being information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The control method includes the following processing: changing the relative position at a prescribed approach speed so that the sample stage and the cantilever are close. The control method includes the following processing: determining a speed reduction position for switching the approach speed from a high speed to a low speed based on the first information and the second information. Changing the relative position includes changing the relative position in such a way that the approach speed changes from a high speed to a low speed at the speed reduction position.

[0166] According to such a structure, the scanning probe microscope detects not only the second information as the position of the sample or the position of the sample stage, but also the first information of the cantilever. Then, the scanning probe microscope can determine the speed drop position for switching the approach speed from high speed to low speed based on the first information and the second information. Therefore, even if the cantilever can move in the thickness direction of the sample, the drop position can be appropriately determined, so that the danger of the cantilever contacting the sample surface can be reduced and the approach action can be performed in a short time.

[0167] In addition, regarding the above-mentioned embodiment and modified examples, it has been planned from the beginning of the application that a combination not mentioned in the specification is included and that the configurations described in the embodiment are appropriately combined within a range that does not cause any inconvenience or contradiction.

[0168] The embodiments disclosed this time should be considered as illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0169] Description of Reference Numerals

[0170] 1: optical system; 2: cantilever; 2a: reflecting member; 3: needle; 3a: front end; 4: bracket; 5: beam splitter; 6: laser source; 7: reflector; 8: light detector; 10: measuring device; 12: micro-motion mechanism; 14: sample table; 14a: configuration surface; 20: information processing device; 22: feedback signal generating unit; 30: display device; 30A: display area; 35: cantilever unit; 40: input device; 45: input area; 50: optical microscope; 50a: detection light; 61: first motor; 62: second motor; 102: detection unit; 104: proximity processing unit; 108: storage unit; 108A: last speed reduction position; 110: detection mechanism; 162: ROM; 164: RAM.

Claims

1. A scanning probe microscope comprising: A sample table, which is used to arrange the sample; a cantilever that scans along the surface of the sample; A displacement mechanism, which changes the relative position of the sample stage and the cantilever in the thickness direction of the sample; a detection mechanism for acquiring first information and second information, wherein the first information is information related to the position of the cantilever in the thickness direction, and the second information is information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction; as well as an approach processing unit that controls the displacement mechanism at a predetermined approach speed so that the sample stage and the cantilever are brought close to each other, wherein the approach processing unit determines a speed reduction position for switching the approach speed from a high speed to a low speed based on the first information and the second information, The approach processing unit controls the displacement mechanism so that the approach speed changes from a high speed to a low speed at the speed reduction position.

2. The scanning probe microscope according to claim 1, wherein: The second information is information indicating the position of the surface of the sample in the thickness direction.

3. The scanning probe microscope according to claim 1, wherein: The sample stage has a placement surface on which the sample is placed. The second information is information indicating the position of the configuration surface in the thickness direction, The proximity processing unit receives input of thickness information indicating the thickness of the sample from a user, The proximity processing unit determines the speed reduction position based on the first information, the second information, and the thickness information.

4. The scanning probe microscope according to claim 3, wherein: The scanning probe microscope performs a prescribed process for the detection mechanism to acquire the second information, After executing the prescribed processing, the detection mechanism obtains the second information.

5. The scanning probe microscope according to claim 4, wherein: The predetermined process includes a process of moving the sample stage.

6. The scanning probe microscope according to any one of claims 1 to 5, wherein: The detection mechanism comprises an optical microscope with a fixed focal length, The cantilever is arranged between the optical microscope and the sample stage in the thickness direction. The scanning probe microscope moves the optical microscope in the thickness direction, The detection mechanism acquires the first information based on the position of the optical microscope at a distance between the cantilever and the optical microscope being the focal length. The detection mechanism acquires the second information based on a position of the optical microscope at which the distance between the sample or the sample stage and the optical microscope is the focal length.

7. The scanning probe microscope according to claim 6, wherein: The cantilever is provided with a reflective member on the side opposite to the portion facing the sample. The cantilever is displaced in such a way that a physical quantity acting between the cantilever and the sample is fixed, The scanning probe microscope further includes a light source for irradiating light toward the reflective member. The scanning probe microscope measures the sample based on reflected light of the light reflected by the reflecting member. The detection mechanism acquires the first information based on a position of the optical microscope at which the distance between the reflective member and the optical microscope is the focal length.

8. The scanning probe microscope according to any one of claims 1 to 5, wherein: The scanning probe microscope further includes a storage device, wherein the storage device stores the speed reduction position determined last time. The approach processing unit controls the displacement mechanism so that the approach speed changes from a high speed to a low speed at the speed reduction position stored in the storage device last time.

9. The scanning probe microscope according to any one of claims 1 to 5, wherein: The proximity processing unit controls the displacement mechanism by performing feedback control until a physical quantity acting between the cantilever and the sample reaches a predetermined quantity.

10. The scanning probe microscope according to any one of claims 1 to 5, wherein: The cantilever moves in the thickness direction independently of the sample stage.

11. A control method, which is a control method for a scanning probe microscope. The scanning probe microscope comprises: a sample stage for placing the sample; and The cantilever scans along the surface of the specimen. in, The relative positions of the sample stage and the cantilever in the thickness direction of the sample are changed. The control method includes the following processing: Acquire first information and second information, wherein the first information is information related to the position of the cantilever in the thickness direction, and the second information is information related to the position of the sample in the thickness direction or the position of the sample stage in the thickness direction; Changing the relative position at a predetermined approach speed so that the sample stage and the cantilever are close to each other; as well as determining a speed reduction position for switching the approach speed from a high speed to a low speed based on the first information and the second information, Here, changing the relative position includes changing the relative position in such a way that the approach speed changes from a high speed to a low speed at the speed reduction position.

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