WO2024014186A1

WO2024014186A1 - Scanning probe microscope and control method

Info

Publication number: WO2024014186A1
Application number: PCT/JP2023/021095
Authority: WO
Inventors: 敬太藤野
Original assignee: 株式会社島津製作所
Priority date: 2022-07-14
Filing date: 2023-06-07
Publication date: 2024-01-18

Abstract

A detecting mechanism (110) acquires first information indicating the position of a cantilever in the Z-axis direction and second information indicating the position of a sample S in the Z-axis direction or the position of a sample stand (14) in the Z-axis direction. An approach processing part (104) determines a speed reduction position on the basis of the first information and the second information. The approach processing part (104) controls a displacement mechanism so that an approach speed changes from high speed to low speed at the speed reduction position.

Description

Scanning probe microscope and control method

The present disclosure relates to a scanning probe microscope and a control method.

A so-called optical lever scanning probe microscope (SPM) includes a cantilever having a probe, a stage on which a sample is placed, and an optical microscope. The optical microscope can be moved by a user or the like independently of the cantilever and stage. A user can visually observe the position of the sample and probe using an optical microscope.

SPM can obtain an uneven image of the surface of a sample by moving the probe of the cantilever along the surface of the sample and detecting the deflection of the cantilever. This type of SPM further includes a light irradiation section that irradiates light toward the cantilever, and a light detection section that receives reflected light from the cantilever.

When starting observation of the sample surface, the SPM first performs an approach operation to bring the cantilever closer to the sample. Specifically, the approach operation is an operation in which the probe gradually approaches the sample surface by moving the cantilever vertically downward. Further, the SPM moves the cantilever through feedback control based on a signal value indicated by a detection signal from the photodetector. Then, when the signal value reaches a preset target value, the SPM determines that the probe has approached the sample surface and stops the movement of the cantilever. The approach operation of the SPM is thus completed, and the sample surface is then observed by scanning the cantilever in the horizontal direction.

Further, Japanese Patent No. 2909828 (Patent Document 1) discloses a scanning tunneling microscope (STM) for measuring a sample. STM does not have a cantilever, but includes a probe, a stage, and an optical microscope. The probe is fixed to the optical microscope. A sample is placed on the stage. Furthermore, the STM moves the stage through feedback control based on tunnel current.

When starting observation of the sample surface, the STM executes an approach operation to bring the probe and the sample closer together by moving the stage on which the sample is placed in the thickness direction of the sample. STM starts measuring a sample when the probe and the sample come close to each other.

STM increases the moving speed of the stage in order to shorten the time required for this approach operation. However, when the moving speed of the stage is increased, the sample and the probe may collide because the above-mentioned feedback control is executed. Therefore, in the STM described in Patent Document 1, the distance between the sample and the probe is calculated, and a speed reduction position where the speed of the stage is reduced is determined based on the distance. The STM then moves the stage at high speed until it reaches the speed reduction position, and when the stage reaches this speed reduction position, moves the stage at low speed.

Patent No. 2909828

The SPM executes the above-mentioned feedback control in the approach operation. Therefore, strictly speaking, the cantilever will stop later than the command to stop the cantilever from the control device, and there is a risk that the probe of the cantilever will collide with the sample. Therefore, in the approach operation, it is conceivable to reduce the moving speed of the cantilever to prevent collision between the probe and the sample. However, if the cantilever is moved at a low speed, the time required for the approach operation becomes large.

Furthermore, it is conceivable to apply the STM technology for determining the speed reduction position described in Patent Document 1 to SPM. However, as mentioned above, in the STM, the probe is fixed relative to the optical microscope. On the other hand, the SPM optical microscope, as described above, is moved independently of the cantilever and stage. Therefore, the STM technique in which the probe is fixed relative to the optical microscope cannot be applied to SPM.

This invention was made to solve these problems, and provides a scanning probe microscope and a control method that can perform an approach operation in a short time while reducing the risk of the cantilever coming into contact with the sample surface. The goal is to provide the following.

The scanning probe microscope of the present disclosure includes a sample stage, a cantilever, a displacement mechanism, a detection mechanism, and an approach processing section. A sample is placed on the sample stage. The cantilever is scanned 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 acquires first information that is information regarding the position of the cantilever in the thickness direction, and second information that is information regarding the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The approach processing section controls the displacement mechanism at a predetermined approach speed so that the sample stage and the cantilever are brought close to each other. The approach processing unit determines a speed reduction position at which the approach speed is switched from high speed to low speed based on the first information and the second information. The approach processing unit also controls the displacement mechanism so that the approach speed changes from high to low at the speed reduction position.

The control method of the present disclosure is a control method of a scanning probe microscope. A scanning probe microscope includes a sample stage on which a sample is placed and a cantilever that scans along the surface of the sample. The relative positions of the sample stage and the cantilever in the thickness direction of the sample are changed. The control method includes acquiring first information regarding the position of the cantilever in the thickness direction, and second information regarding the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The control method includes changing the relative position of the sample stage and the cantilever at a predetermined approach speed so that the sample stage and the cantilever become close to each other. The control method includes determining a speed reduction position at which the approach speed is switched from high speed to low speed based on the first information and the second information. Changing the relative position includes changing the relative position such that the approach speed is from high to low at the reduced speed position.

According to the scanning probe microscope and control method of the present disclosure, it is possible to perform an approach operation in a short time while reducing the risk of the cantilever coming into contact with the sample surface.

1 is a diagram schematically showing the configuration of an SPM of the present disclosure. 1 is a diagram illustrating an example of a hardware configuration of an information processing device. FIG. 2 is a functional block diagram showing the main functions of the information processing device. FIG. 3 is a diagram showing a method of determining a speed reduction position according to the first embodiment. FIG. 3 is a diagram showing a method of determining a speed reduction position according to the first embodiment. 2 is a flowchart showing the flow of SPM processing according to the first embodiment. It is a figure showing an example of a mode setting screen of a 1st embodiment. This is an example of an input screen. It is a figure which shows the method of determining a speed reduction position of 2nd Embodiment. It is a figure which shows the method of determining a speed reduction position of 2nd Embodiment. 7 is a flowchart showing the flow of SPM processing according to the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts in the figures are denoted by the same reference numerals, and the description thereof will not be repeated.

<First embodiment>
[Configuration example]
FIG. 1 is a diagram schematically showing the configuration of a scanning probe microscope (SPM) according to the present disclosure. The scanning probe microscope is also referred to as SPM100. The SPM 100 typically 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. The SPM 100 may be an atomic force microscope (AFM). In this case, the physical quantity is an atomic force (attraction or repulsion).

As shown in FIG. 1, 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, as main components, an optical system 1, a cantilever 2, a fine movement mechanism 12 (scanner), a sample stage 14, an XY direction drive section 16, a Z direction drive section 18, and a feedback signal generation section. 22, a first motor 61, a second motor 62, and an optical microscope 50. In this embodiment, the first motor 61 and the second motor 62 are typically stepping motors.

The surface of the sample stage 14 is a 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 will be referred to as the Z-axis direction, and the directions perpendicular to the Z-axis direction will be referred to as the X-axis direction and the Y-axis direction. It is also the height direction of the SPM 100 in the Z-axis direction.

The sample stage 14 is placed on the fine movement mechanism 12. The fine movement mechanism 12 is a moving device for changing the relative positional relationship between the sample S and the probe 3 during analysis of the sample S. The fine movement mechanism 12 includes an XY scanner 12xy and a Z scanner 12z. The XY scanner 12xy moves the sample stage 14 in the X-axis direction and the Y-axis direction. The Z scanner 12z slightly moves the sample stage 14 in the Z-axis direction. The XY scanner 12xy has a piezoelectric element that is deformed by a voltage applied from the XY direction drive unit 16. The Z scanner 12z has a piezoelectric element that expands and contracts in response to a voltage applied from the Z direction drive unit 18. This piezoelectric element allows the Z scanner 12z to expand and contract. Note that the XY scanner 12xy and the Z scanner 12z are not limited to having a piezoelectric element.

The cantilever 2 is placed facing the sample stage 14. The cantilever 2 is formed in the shape of a leaf spring, and one end thereof is supported by a holder 4. That is, the one end is a fixed end. Further, the other end of the cantilever 2 is a free end, and is arranged to face the sample S on the sample stage 14. In the example shown in FIG. 1, it is arranged above the Z-axis direction. The tip of the free end of the cantilever 2 has a front surface and a back surface opposite to the front surface. The surface is the surface facing the sample S. Further, a probe 3 is arranged on the surface so as to face the sample S. During analysis of the sample S, the cantilever 2 is scanned along the surface of the sample S.

Furthermore, a reflective member 2a that reflects light is formed on the back surface of the cantilever 2. The reflective member 2a may be coated with a predetermined material (aluminum, gold, etc.), for example. A physical quantity (for example, atomic force) acting between the probe 3 and the sample S causes the tip of the free end of the cantilever 2 to be displaced in the Z-axis direction.

An optical system 1 is provided above the cantilever 2 in the Z-axis direction to detect the amount of deflection of the cantilever 2 (that is, the amount of displacement of the tip). 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 by the reflective surface. Specifically, the optical system 1 includes a laser light source 6, a beam splitter 5, a reflecting mirror 7, and a photodetector 8.

The laser light source 6 has a laser oscillator that emits laser light. The photodetector 8 has a photodiode that detects the incident laser light. Laser light LA emitted from laser light source 6 is reflected by beam splitter 5 and irradiated onto reflective member 2a of cantilever 2. The laser beam reflected from the back surface of the cantilever 2 is further reflected by a reflecting mirror 7 and enters a photodetector 8.

The photodetector 8 has a light-receiving surface that is divided into a plurality of (for example, two) parts in the Z-axis direction (displacement direction) of the cantilever 2. Alternatively, the photodetector 8 has a light receiving surface divided into four parts 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 amount of deflection (amount of displacement) of the cantilever 2 is detected based on the amount of light received by the plurality of light receiving surfaces. can do.

Further, 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 specify the observation range, and adjusts the irradiation position of the laser beam to match the reflection member 2a of the cantilever 2. Image data acquired by the optical microscope 50 is output to the information processing device 20.

The feedback signal generator 22 calculates the amount of deflection of the cantilever 2 by processing the detection signal provided from the photodetector 8. The feedback signal generator 22 controls the position of the sample S in the Z direction so that the atomic force between the probe 3 and the sample S is constant. In the following, this control will also be referred to as "feedback control." Specifically, the feedback signal generation unit 22 calculates the deviation Sd between the calculated amount of deflection of the cantilever 2 and the target value, and calculates the control amount for driving the Z scanner 12z so that the deviation Sd becomes zero. do. The feedback signal generator 22 calculates a voltage value Vz for displacing the Z scanner 12z in accordance with this control amount. Feedback signal generation section 22 outputs a voltage signal indicating voltage value Vz to Z-direction drive section 18 . The Z-direction drive section 18 applies a voltage value Vz to the Z scanner 12z. In this way, the Z-direction drive section 18 receives the voltage value input from the feedback signal generation section 22, and applies a voltage based on the voltage value to the Z scanner 12z.

The information processing device 20 controls the XY direction drive unit 16 to a voltage value Vx in the X axis direction so that the sample stage 14 moves relative to the probe 3 in the X axis and Y axis directions according to preset scanning conditions. Then, a voltage value Vy in the Y-axis direction is calculated and outputted to the XY-direction drive unit 16. The XY direction drive section 16 applies voltage values Vx and Vy to the XY scanner 12xy.

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

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

The measurement data created by the information processing device 20 includes a value (Z value) indicating the position in the Z-axis direction at each position on the XY plane. Note that the Z value is the height of the sample S at each position. Further, for example, the position in the Z-axis direction is represented by a Z coordinate with the origin as a reference. The origin in the Z-axis direction is, for example, the position of the placement surface 14a when the sample stage 14 is at the lowest position. In this way, the SPM 100 (information processing device 20) measures the surface state of the sample S based on the light reflected by the reflecting member 2a.

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 display (LCD) panel. The information processing device 20 causes the display device 30 to display information such as the shape of the surface of the sample S based on the created measurement data. Further, the information processing device 20 causes the display device 30 to display image data acquired by the optical microscope 50, an input screen to be described later, and the like. Further, the input device 40 is, for example, a keyboard or a pointing device such as a mouse, and receives commands from a user. When a touch panel is used as a user interface, input device 40 and display device 30 are integrally formed. Further, the information processing device 20 corresponds to a “control device” of the present disclosure.

Image data acquired by imaging with the optical microscope 50 is output to the information processing device 20. The information processing device 20 may display the image data on the display device 30.

The user can specify the observation location by focusing the optical microscope 50 on the sample S, and can adjust the laser beam irradiation position to match the cantilever 2. The cantilever 2 is arranged between the optical microscope 50 and the sample stage 14 in the Z-axis direction.

The cantilever unit 35 is movable in the X-axis direction, Y-axis direction, and Z-axis direction by the driving force of the first motor 61. Further, the information processing device 20 can control the first motor 61 by outputting a pulse signal to the first motor 61. Further, the information processing device 20 can specify the amount of movement of the cantilever unit 35 based on the number of pulses of the pulse signal. The amount of movement of the cantilever unit 35 is, for example, the amount of movement of the cantilever unit 35 from its initial position. Furthermore, the information processing device 20 can control the moving speed of the cantilever unit 35 (cantilever 2) by, for example, controlling the frequency of the pulse signal applied 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 at low speed.

Note that the first motor 61 has a screw that transmits driving force to the cantilever unit 35. The information processing device 20 may specify a value obtained by multiplying the pitch of the screw by the number of applied pulses as the amount of movement of the cantilever unit 35.

Furthermore, the information processing device 20 can move the cantilever unit 35 by controlling the first motor 61 based on a user's command to the input device 40. For example, when placing the sample S on the sample stage 14, the user inputs a command to raise the cantilever unit 35 into 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, making it easier to place the sample S on the sample stage 14, which is convenient for the user. Improves sex.

Furthermore, the optical microscope 50 is movable in the X-axis direction, Y-axis direction, and Z-axis direction by the driving force of the second motor 62. Further, the information processing device 20 can control the second motor 62 by outputting a pulse signal to the second motor 62. Further, the information processing device 20 can specify the amount of movement of the optical microscope 50 and the position of the optical microscope 50 based on the number of pulses of the pulse signal. The amount of movement of the optical microscope 50 is, for example, the amount of movement of the optical microscope 50 from its initial position. Note that the second motor 62 has a screw that transmits power to the optical microscope 50. The information processing device 20 may specify a value obtained by multiplying the pitch of the screw by the number of applied pulses as the amount of movement of the optical microscope 50.

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

[Hardware configuration of information processing device]
FIG. 2 is a diagram showing an example of the hardware configuration of the information processing device 20. As shown in FIG. Referring to FIG. 2, the information processing device 20 includes a CPU (Central Processing Unit) 160, a ROM (Read Only Memory) 162, a RAM (Random Access Memory) 164, and an HDD (Hard Disk Drive) as main components. ) 166, a communication I/F (Interface) 168, a display I/F 170, an input I/F 172, and a motor I/F 174. Each component is interconnected by a data bus. Note that at least a portion of the hardware configuration of the information processing device 20 may be located inside the measurement device 10. Alternatively, the information processing device 20 may be configured separately from the SPM 100 and configured to communicate bidirectionally with the SPM 100.

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

The ROM 162 stores programs executed by the CPU 160. The RAM 164 can temporarily store data generated by executing programs in the CPU 160 and data input via the communication I/F 168. RAM 164 may function as a temporary data memory used as a work area. HDD 166 is a nonvolatile storage device. Instead of the HDD 166, a semiconductor storage device such as a flash memory may be used.

The program stored in the ROM 162 may be stored in a non-temporary storage medium and distributed as a program product. Alternatively, the program may be provided by an information provider as a downloadable product program over the so-called Internet. The information processing device 20 reads a program provided from a storage medium or the Internet. The information processing device 20 stores the read program in a predetermined storage area (eg, ROM 162). By executing the program, the CPU 160 can perform image data acquisition processing, which will be described later. The information processing device 20 is also referred to as a "control device" or a "control circuit."

[Example of functional configuration of information processing device]
FIG. 3 is a functional block diagram showing the main functions of the information processing device 20. As shown in FIG. The information processing device 20 includes a detection section 102, an approach processing section 104, and a storage section 108. Further, 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 by the approach processing unit 104 will be described later. A detection mechanism 110 is configured by the optical microscope 50, the detection section 102, and the second motor 62.

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

Furthermore, 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.

The approach processing unit 104 controls the first motor 61 at an approach speed described below. Furthermore, the approach processing unit 104 determines the 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. The approach processing unit 104 also controls the first motor 61 so that the approach speed changes from high to low at the speed reduction position. The storage unit 108 stores a previous speed reduction position 108A, which will be described later. Furthermore, the storage unit 108 stores programs such as calculation formulas to be described later.

Data of an image captured by the optical microscope 50 (hereinafter also referred to as "image data") is input to the detection unit 102 from the optical microscope 50. The detection unit 102 may detect whether or not the image data is focused on the object, as will be described later.

[Determination of speed reduction position]
Next, a method for determining the speed reduction position will be explained. In this embodiment, the focal length L3 of the optical microscope 50 is constant at least during the period when the approach process is being executed.

The SPM 100 starts measuring the sample S when a predetermined starting condition is met. The start condition includes the following first condition and second condition. The first condition is a condition that is satisfied when the user performs a start operation on the input device 40. The second condition is a condition that is established when the SPM 100 detects completion of placement of the sample S to be measured.

As described above, in order to improve user convenience, the cantilever unit 35 including the cantilever 2 is movable in the Z-axis direction by the user's operation. In particular, since the cantilever unit 35 is moved upward to place the sample S on the sample stage 14, the cantilever 2 (probe 3) and the sample S may be far apart from each other after the sample is placed. Therefore, when the above-mentioned start condition is satisfied, the SPM 100 of this embodiment executes the approach process. The approach process is a process of bringing the cantilever 2 close to the sample S. Approach processing is also referred to as "approach operation." Further, in the approach process (during the approach period), the speed at which the cantilever 2 (cantilever unit 35) is brought close to the sample S is also referred to as "approach speed."

More specifically, the approach process is a process in which the cantilever 2 is brought close to the sample S while performing feedback control until the physical quantity (for example, atomic force) that the cantilever 2 receives 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. Note that in the approach process, instead of the physical quantity, a value corresponding to the physical quantity (for example, the amount of deflection of the cantilever 2) may be used.

In the approach process in this embodiment, the sample stage 14 is fixed, while the cantilever 2 is lowered. Furthermore, during the analysis of the sample S, the SPM 100 drives the sample stage 14 in the Z-axis direction by the Z-direction drive unit 18, and fixes the cantilever 2. As a modification, during 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.

In order to shorten the time for approach processing, the information processing device 20 may increase the descending speed (approach speed) of the cantilever 2. However, if the descending speed of the cantilever 2 is too fast, even if the above-mentioned physical quantity reaches the specified value and the measurement device 10 receives a stop command from the information processing device 20, the cantilever will move later than the reception of the stop command. 2 will stop. Therefore, there is a risk that the cantilever 2 and the sample S will collide. In this case, at least one of the probe 3 and the sample S may be damaged. Conversely, if the approach speed is slowed down to prevent collision between the cantilever 2 and the sample S, the approach process will take a lot of time.

Therefore, the SPM 100 of this embodiment determines the speed reduction position in order to shorten the approach processing time and reduce collisions between the cantilever 2 and the sample S. Then, the SPM 100 lowers the cantilever unit 35 at a first speed to the speed reduction position, and upon reaching the speed reduction position, lowers the cantilever unit 35 at a second speed. Here, the second speed is slower than the first speed. The first speed corresponds to "high speed" in the present disclosure, and the second speed corresponds to "low speed" in 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.

Since the SPM 100 lowers the cantilever 2 at high speed to the speed reduction position, the time for approach processing can be shortened. Furthermore, since the cantilever 2 is lowered at a low speed after reaching the speed reduction position, even if the stop of the cantilever 2 is delayed from the stop command of the feedback control, there is a possibility that the cantilever 2 and the sample S will collide. Can be reduced.

FIGS. 4 and 5 are diagrams for explaining the method of determining the speed reduction position of this embodiment. FIG. 4(A) is a diagram for explaining a method of acquiring first information, and FIG. 4(B) is a diagram for explaining a method of acquiring second information. FIG. 5 is a diagram for explaining a method of determining the speed reduction position based on the first information and the second information.

First, the information processing device 20 acquires image data from the optical microscope 50 while lowering the optical microscope 50. The detection unit 102 of the information processing device 20 detects whether or not the target object is in focus in the image data. Then, when it is detected that the object is in focus, the detection unit 102 stores the position of the optical microscope 50 (the number of pulses of the second motor 62) at that time.

In the present embodiment, the information processing device 20 repeats this process twice, and recognizes the first focused position after starting the descent as information regarding the position of the cantilever 2 (first information). Then, the information processing device 20 recognizes the second focused position as information regarding the position of the sample S (second information).

Regarding the method of detecting whether or not the target object is in focus, in this embodiment, a method is adopted in which the detection unit 102 processes image data in real time and automatically performs the detection. As such a method, any conventionally known method can be appropriately employed, such as a contrast method.

This will be explained specifically using FIG. 4. FIG. 4A is a diagram showing a state in which it is detected by a predetermined method (for example, the above-described contrast method) that the object is in focus for the first time after the optical microscope 50 starts descending. The detection unit 102 acquires the number of pulses of the second motor 62 in this state as first information. This first information is information regarding the position of the cantilever 2 (reflection member 2a) in the Z-axis direction.

When the detection unit 102 acquires the first information, the information processing device 20 executes a retraction process so that the detection light 50a from the optical microscope 50 does not hit the cantilever 2. This 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 it focuses on the object again.

FIG. 4(B) is a diagram showing a state in which it is detected by a predetermined method that the object is in focus for the first time after executing the evacuation process. The detection unit 102 acquires the number of pulses of the second motor 62 at this point as second information. This second information is information regarding the position of the sample S (sample surface Sa) in the Z-axis direction. As described above, the detection unit 102 (detection mechanism 110) acquires the first information and the second information based on the detection by the optical microscope 50.

Here, in the state of FIG. 4(A), the distance between the lens of the optical microscope 50 and the reflecting member 2a of the cantilever 2 should be the focal length L3 of the optical microscope 50. Further, in the state shown in FIG. 4(B), the distance between the lens of the optical microscope 50 and the reflecting member 2a on the sample surface Sa should be the focal length L3 of the optical microscope 50. Since the distance L3 is constant, the distance L1 and the distance L2 are the same, as shown in FIG. 4(A). The distance L1 is the distance that the optical microscope 50 has descended (see FIG. 4(B)). The distance L2 is the distance from the reflecting member 2a (more precisely, the location on which the detection light of the reflecting member 2a hits) to the sample surface Sa. In other words, the distance L2 is the distance between the cantilever 2 and the sample S.

In this way, the approach processing unit 104 generates "first information (the number of pulses of the second motor 62 when the cantilever is in focus)" and "second information (the second information when the sample surface is in focus)". The distance L2 can be calculated based on the difference value between the two motors 62 (the number of pulses of the two motors 62). For example, the approach 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.

The approach processing unit 104 determines the speed reduction position α based on the calculated distance L2. This will be explained in detail with reference to FIG.

The distance L4 from the reflecting member 2a to the tip 3a of the probe 3 is a fixed value determined by the type of cantilever used. Further, a certain distance from the sample surface Sa is defined as a distance L6. The distance L6 is a distance so close to the sample that the physical quantity received by the cantilever 2 from the sample S may reach a specified value, and is a fixed value determined by the user depending on 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 desirable to start reducing the approach speed, for example 0.5 mm. Note that the distance L4 and the distance L6 may be changeable by the user.

The approach 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 approach processing unit 104 calculates a distance L7 for moving the cantilever at high speed by subtracting the distance L6 from the distance L5. That is, the approach processing unit 104 calculates the distance L7 using the following equation (1).

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

L7=L1-M1 (2)
In this way, the approach processing unit 104 can calculate the distance L5 between the tip 3a of the probe and the sample surface Sa based on the first information and the second information. Furthermore, a distance L7 for moving the cantilever at high speed can be calculated from the distance L5 and a fixed value stored in advance. In other words, it is possible to determine the speed reduction position α where the approach speed of the cantilever 2 (cantilever unit 35) is reduced. Then, the approach processing unit 104 controls the first motor 61 so that the cantilever 2 and the sample S approach each other and the approach speed is reduced at the speed reduction position α.

In other words, the approach processing unit 104 moves the cantilever 2 located at the current position (the position of the cantilever 2 shown in FIG. 5) by the distance L7 at the first speed (high speed). After moving the distance L7, the cantilever 2 reaches the speed reduction position α, and the approach speed of the cantilever 2 is changed 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. With this control, the cantilever 2 can move at high speed from the initial position to the speed reduction position α, and can move at low speed from the speed reduction position α. As a result, the SPM 100 can perform the approach operation in a short time while reducing the risk of the cantilever 2 coming into contact with the sample surface Sa.

While the separation distance L6 between the speed reduction position α and the sample surface is a fixed value, the separation distance L7 from the tip 3a of the probe varies depending on the height of the cantilever 2 at any given time, and cannot be determined using conventional techniques. There wasn't. Even if the absolute value of the height of the cantilever 2 could be recognized, the distance L7 could still not be determined because the height of the surface of the sample on which it was placed was unknown.

In the present embodiment, the distance L7 can be determined based on the first information and second information calculated by the optical microscope 50. It should be noted that since the distance between the sample surface and the cantilever 2 is calculated, there is no need to calculate the absolute value of the height of the sample surface or the cantilever.

Furthermore, in the present embodiment, the second information is information indicating the position of the sample surface Sa in the Z-axis direction. Therefore, when the detection mechanism 110 detects the sample surface Sa, the information processing device 20 can acquire the second information.

Furthermore, the focal length L3 of the optical microscope 50 is constant at least during the period in which the approach process is being executed. Therefore, compared to a configuration in which the focal length L3 of the optical microscope 50 is variable, the processing amount of the optical microscope 50 can be reduced.

Furthermore, in this embodiment, the reflecting member 2a of the cantilever 2 used to measure the sample can be used both as the reflecting member 2a used to obtain the first information. Therefore, compared to an SPM in which the reflective member used to measure the sample and the reflective member used to acquire the first information are separate, the SPM 100 of this embodiment can reduce the number of parts.

Furthermore, in the present embodiment, the optical microscope 50 for displaying image data in a period other than the approach period can be used both as the optical microscope 50 for acquiring the first information and the second information. Therefore, compared to an SPM in which the optical microscope for displaying the detected image and the optical microscope for acquiring the first information and the second information are separate, the scanning probe microscope of the present disclosure reduces the number of parts. can.

[flowchart]
FIG. 6 is a flowchart showing the processing flow of the SPM 100 of this embodiment. The flowchart of FIG. 6 starts when the above-mentioned start condition is satisfied. First, in step S102, the SPM 100 acquires first information (information regarding the position of the cantilever in the Z-axis direction) (see FIG. 4(A)).

Next, in step S104, the SPM 100 acquires second information (information regarding the position of the sample surface Sa in the Z-axis direction) (see FIG. 4(B)). Next, in step S106, the SPM 100 determines the speed reduction position α (see FIG. 5). Next, in step S108, the SPM 100 executes approach processing based on the speed reduction position α. Then, when the approach process ends, the SPM 100 starts measuring the sample S in step S110.

[Previous speed reduction position]
Next, the previous speed reduction position 108A in FIG. 3 will be explained. The thickness of the sample S to be measured this time may be the same or approximately the same as the thickness of the sample S measured last time. In this case, the speed reduction position α is the same between the previous measurement and the current measurement. Therefore, if the user is aware that the thickness of the sample S to be measured this time is the same or approximately the same as the thickness of the sample S measured last time, the previously determined speed reduction position It is preferable that the information processing device 20 uses this as the speed reduction position α in the measurement.

When the information processing device 20 determines the speed reduction position α, it stores it as the previous speed reduction position 108A. Furthermore, the user can select whether or not to use the previous speed reduction position 108A as the current speed reduction position.

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

The user can select (set) a desired mode by inputting a command to the mode setting screen shown in FIG. In the example of FIG. 7, when a radio button corresponding to a desired mode is selected and the OK button 44 is operated, the mode is set. Setting a mode is realized, for example, by storing a mode flag indicating the mode in a predetermined storage area.

When the normal mode is set by the user, the information processing device 20 determines the speed reduction position α through the process shown in FIG. A case where the same mode was set last time by the user will be explained.

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

According to such a configuration, the cantilever 2 can be moved based on the previously determined speed reduction position, so the process of lowering the optical microscope 50 and the process performed on image data acquired by the optical microscope 50 can be reduced. can do.

<Second embodiment>
Next, a second embodiment will be described. For example, the sample S may have characteristics that make it impossible to focus the optical microscope 50. This characteristic is a characteristic that the sample surface Sa does not have a certain degree of contrast, such as being black. In such a case, it may not be possible to focus the optical microscope 50 on the sample S, and the speed reduction position α may not be determined. Therefore, in the second embodiment, a configuration will be described in which the speed reduction position α can be determined even when the optical microscope 50 cannot be focused on the sample S.

The arrangement surface 14a of the second embodiment is a reflective member. This reflective member is, for example, a mirror. In this way, since the arrangement surface 14a is a reflective member, the SPM 100 can focus the optical microscope 50 on the arrangement surface 14a. Therefore, the detection mechanism 110 can acquire the position of the placement surface 14a in the Z-axis direction as second information.

That is, in the second embodiment, the information processing device 20 recognizes the position of the object that the optical microscope 50 focuses on the first time after starting the descent as the position of the cantilever 2 (first information), and the second time The position of the object on which the optical microscope 50 is focused is recognized as the position of the arrangement surface 14a (second information).

Further, if the sample S exists at a position where the optical microscope 50 is in focus, the detection mechanism 110 is obstructed by the sample S and cannot detect the placement surface 14a. Therefore, in the second embodiment, the SPM 100 executes a predetermined process for the detection mechanism 110 to detect the position of the placement surface 14a. The predetermined process of this embodiment is, for example, a process of moving the sample stage 14 a predetermined distance in a predetermined direction on the XY plane. Through this process, the sample S can be evacuated, and as a result, the detection mechanism 110 can detect the placement surface 14a (can acquire the second information). This predetermined process is also referred to as "sample S evacuation process." Furthermore, when the placement surface 14a is detected, the SPM 100 moves the sample stage 14 so that the sample S returns to its original position.

Furthermore, in this embodiment, the thickness of the sample S is used to determine the speed reduction position α. The thickness of the sample S is input by the user, for example. FIG. 8 is an example of an input screen where the thickness of the sample is input. For example, this input screen is displayed on the display area 30A of the display device 30 when the above-mentioned start condition is satisfied. In the example of FIG. 8, an input area 45 is displayed. The user inputs the thickness of the sample into the input area 45.

FIGS. 9 and 10 are diagrams for explaining the method of determining the speed reduction position of this embodiment. Note that FIGS. 9 and 10 show the state after the sample S evacuation process has been executed. Similarly to FIG. 4A, FIG. 9A shows that the information processing device 20 has acquired first information (information regarding the position of the cantilever 2 in the Z-axis direction). Further, FIG. 9B shows that the information processing device 20 has acquired the second information (information regarding the position of the placement surface 14a in the Z-axis direction).

Furthermore, in FIGS. 9(A) and 9(B), the distance L3 (focal length of the optical microscope 50) is constant. Therefore, as shown in FIG. 9(A), the distance L11 and the distance L12 are the same. The distance L11 is the distance that the optical microscope 50 has descended (see FIG. 9(B)). The distance L12 is the distance from the reflecting member 2a (more precisely, the location where the detection light of the reflecting member 2a hits) to the arrangement surface 14a. In other words, the distance L12 is the distance between the cantilever 2 and the arrangement surface 14a.

Furthermore, as shown in FIG. 10, the approach processing unit 104 determines the speed reduction position α based on the distance L12. As shown in FIG. 10, the thickness of the sample is a distance L18. Here, the thickness of the sample (distance L18) is an input value that is input in advance by the user on the input screen of FIG.

The approach 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 arrangement surface 14a. Further, the approach processing unit 104 calculates the distance L17 by subtracting the distance L6 and the distance L18 from the distance L15. That is, the approach processing unit 104 calculates the distance L17 using the following equation (3).

L17=L12-L4-L6-L18 (3)
Here, the distance L12 on the right side of equation (3) is the same as the distance L11, which is the descending distance of the optical microscope 50. Further, the distance L4 and the distance L6 on the right side of equation (3) are the above-mentioned total value M. That is, the distance L17 can also be expressed by the following equation (4).

L17=L11-L18-M1 (4)
FIG. 11 is a flowchart showing the processing flow of the information processing device 20 of this embodiment. In FIG. 11, steps S120 and S122 are added before step S102 in FIG. 6, and step S104 is replaced by step S124.

When the above-mentioned start condition is satisfied, the information processing device 20 executes the evacuation process of the sample S in step S120. Next, in step S122, the information processing device 20 acquires the thickness of the sample S input by the user (see FIG. 8).

After the process of step S102 is completed, the information processing device 20 acquires second information (the position of the sample stage 14 in the Z-axis direction) in step S124. After that, the information processing device 20 executes the process of step S106.

In this way, the information processing apparatus 20 of the present embodiment can process the first information and the second information even if the sample S has a characteristic that the optical microscope 50 cannot focus on the sample S. , and the thickness of the sample (distance L18), the speed reduction position α can be determined.

Furthermore, the information processing device 20 executes a saving process (predetermined process) for the sample S (step S120). Therefore, even if the sample S exists in a position that prevents the information processing device 20 from acquiring the second information, the information processing device 20 can acquire the second information.

Furthermore, the evacuation process of the sample S is a process of moving the sample stage 14 in the XY plane. Therefore, the SPM 100 can realize the evacuation process of the sample S through a relatively simple process.

<Modified example>
(1) In the above embodiment, the SPM 100 is configured to move (lower) the cantilever 2 without moving the sample stage 14 (the sample stage 14 is fixed) during approach processing. However, in the approach process, a configuration may be adopted in which the cantilever 2 is not moved (the cantilever 2 is fixed) and the sample stage 14 is moved (raised). In this configuration, the SPM 100 determines the speed reduction position α based on the distance L2 or the distance L12. Then, the SPM 100 moves (raises) the sample stage 14 at the third speed until the speed reduction position α, and from when the sample stage 14 reaches the speed reduction position α, the sample stage 14 moves at a fourth speed (slower than the third speed). The sample stage 14 is moved (raised) at a speed (speed).

Additionally, the SPM 100 may move the cantilever 2 (lower) and the sample stage 14 (raise) during the approach process. In this case, the speed reduction position of the cantilever 2 (hereinafter referred to as "first speed reduction position α1") and the speed reduction position of the sample stage 14 (hereinafter referred to as "first speed reduction position α1") are determined based on the distance L2 or the distance L12, etc. (referred to as "second speed reduction position α2"). In the approach process, the SPM 100 moves (lowers) the cantilever 2 at the first speed until it reaches the first speed reduction position α1, and then moves the cantilever 2 at a second speed from when it reaches the first speed reduction position α1. to move (lower) the sample stage 14. Further, the SPM 100 moves (raises) the sample stage 14 at the third speed until the second speed reduction position α2, and from when the sample stage 14 reaches the second speed reduction position α2, the sample stage 14 moves (raises) at the fourth speed. Move (raise) 14. 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 approach speed mentioned above is the speed of change of relative position. Even an SPM employing such a configuration provides the same effects as the above-mentioned SPM.

(2) In the above embodiment, the first information is the position of the reflecting member 2a of the cantilever 2 in the Z-axis direction. However, the first information may be any other part of the cantilever 2. The first information may be, for example, the position of the probe 3 in the Z-axis direction.

(3) In the embodiment described above, the optical microscope 50 was exemplified as the detection device that detects the first information and the second information. However, the detection device may be any other device. Other devices may be, for example, a camera or a microscope (eg, an electron microscope) associated with optical microscope 50.

(4) Furthermore, in the above-described embodiment, a configuration was described in which the focal length of the optical microscope 50 is constant during the approach period. However, it is sufficient that the approach processing unit 104 can recognize the focal length of the optical microscope 50, and it may be variable. When such a configuration is adopted, the first information and the second information may be recognized by changing the focal length, for example. That is, the focal length of the optical microscope 50 is changed stepwise so that it becomes longer, and the focal length when the focus is first achieved is recognized as L3. The focal length when the object is in focus the second time is recognized as L1+L3. By subtracting these, the distance L2 (=L1) between the cantilever 2 and the sample surface can be recognized.

If such a configuration is adopted, for example, the information processing device 20 can acquire the first information and the second information while the optical microscope 50 is fixed. Therefore, the process of moving the optical microscope 50 can be reduced.

Alternatively, after the optical microscope 50 acquires the first information, the focal length for acquiring the second information may be calculated by adding a predetermined value to the focal length when acquiring the first information. good. The information processing device 20 determines whether the second information can be acquired based on the calculated new focal length. If the information processing device 20 is unable to acquire the second information due to lack of focus, the information processing device 20 acquires the second information by driving the optical microscope 50 . In the case of such a configuration, the moving distance of the optical microscope 50 can be reduced.

(5) In the above-described embodiment, a configuration in which the optical microscope 50 automatically focuses was described. However, a configuration may also be adopted in which the user manually focuses the optical microscope 50. For example, the information processing device 20 manually focuses 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 placement surface 14a in the Z-axis direction. It may also be detected.

(6) In the above-described embodiment, a configuration was explained in which the predetermined process for the detection mechanism 110 to acquire the second information is a process to evacuate the sample S by moving the sample stage 14 (FIG. 11 (See step S120, etc.). However, the predetermined process may be any other process. The predetermined process may be, for example, a process of moving the optical microscope 50 a predetermined distance in a predetermined direction on the XY plane.

Alternatively, with the cantilever 2 within the field of view, the optical microscope 50 may be lowered until it focuses on the structure (sample stage) behind it. In this case, the SPM 100 does not need to retract the cantilever 2.

Furthermore, the speed reduction position α may be determined before the sample S having the above-mentioned characteristics is placed. For example, the information processing apparatus 20 lowers the optical microscope 50 before the sample S is placed. The object that is in focus the first time after the optical microscope 50 starts descending is recognized as the position of the cantilever 2 (first information), and the object that is focused the second time is recognized as the position of the sample S (second information). information). Then, the information processing device 20 acquires the thickness of the sample S by displaying the input screen of FIG. 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 the speed reduction position α is determined, the information processing device 20 executes a promotion notification that promotes placing the sample S on the sample stage 14. The promotion notification is, for example, a process of displaying a character image such as "Please place the sample" on the display device 30. When the sample S is placed and the user performs a start operation, the information processing device 20 executes the approach process. According to such a configuration, the speed reduction position α can be determined without performing predetermined processing.

(7) In the examples of FIGS. 4 and 9, the optical microscope 50 is shown as a simplified rectangle. In the examples of FIGS. 4 and 9, the distance between the optical microscope 50 and the object to be detected (the reflective member 2a of the cantilever 2, the sample surface Sa) is the distance between the lower side of the rectangle and the object to be detected. . However, this distance may be the distance between a predetermined member of the optical microscope 50 and the object to be detected. The predetermined member may be, for example, an optical system (lens) included in the optical microscope 50.

[Mode]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects.

(Section 1) The scanning probe microscope of the present disclosure includes a sample stage, a cantilever, a displacement mechanism, a detection mechanism, and an approach processing section. A sample is placed on the sample stage. The cantilever is scanned 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 acquires first information that is information regarding the position of the cantilever in the thickness direction, and second information that is information regarding the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The approach processing section controls the displacement mechanism at a predetermined approach speed so that the sample stage and the cantilever are brought close to each other. The approach processing unit determines a speed reduction position at which the approach speed is switched from high speed to low speed based on the first information and the second information. The approach processing unit also controls the displacement mechanism so that the approach speed changes from high to low at the speed reduction position.

According to such a configuration, the scanning probe microscope detects not only the second information, which is 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 a speed reduction 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 is movable in the thickness direction of the sample, the lowering position can be determined appropriately, and the approach operation can be performed in a short time while reducing the risk of the cantilever coming into contact with the sample surface. .

(Section 2) In the scanning probe microscope according to Item 1, the second information is information indicating the position of the surface of the sample in the thickness direction.

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

(Section 3) In the scanning probe microscope according to Item 1, the sample stage has a placement surface on which the sample is placed. The second information is information indicating the position of the placement surface in the thickness direction. The approach processing unit receives input of thickness information indicating the thickness of the sample from the user. The approach processing unit determines the speed reduction position based on the first information, the second information, and the thickness information.

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

(Section 4) In the scanning probe microscope described in Section 3, the scanning probe microscope executes a predetermined process for the detection mechanism to acquire the second information. The detection mechanism acquires the second information after the predetermined process is executed.

According to such a configuration, even if the detection mechanism cannot be acquired due to obstruction of the sample, for example, the second information indicating the position of the placement surface can be acquired by executing the predetermined process.

(Section 5) In the scanning probe microscope according to Item 4, the predetermined process includes a process of moving the sample stage.

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

(Section 6) In the scanning probe microscope according to any one of Items 1 to 5, the detection mechanism includes an optical microscope having a constant focal length. The cantilever is arranged between the optical microscope and the sample stage in the thickness direction. A scanning probe microscope moves an optical microscope in the thickness direction. The detection mechanism acquires first information based on the position of the optical microscope where the distance between the cantilever and the optical microscope is a focal length. Second information is acquired based on the position of the optical microscope where the focal length is the distance between the sample or sample stage and the optical microscope.

According to such a configuration, the first information and the second information can be acquired using a microscope with a relatively simple configuration.

(Section 7) In the scanning probe microscope described in Item 6, the cantilever has a reflecting member formed on the opposite side of the portion facing the sample. The displacement is made so that the physical quantity acting between the cantilever and the sample remains constant. The scanning probe microscope further includes a light source that irradiates the reflective member with light. A scanning probe microscope measures a sample based on light reflected from a reflecting member. The detection mechanism acquires the first information based on the position of the optical microscope where the distance between the reflecting member and the optical microscope is a focal length.

According to such a configuration, the reflecting member used to measure the sample and the reflecting member used to obtain the first information can be used both. Therefore, compared to a scanning probe microscope in which the reflective member used to measure the sample and the reflective member used to acquire the first information are separate, the scanning probe microscope of the present disclosure has fewer parts. can be reduced.

(Section 8) The scanning probe microscope according to any one of Items 1 to 5 further includes a storage device that stores the previously determined speed reduction position. The approach processing unit controls the displacement mechanism so that the approach speed changes from high to low at the speed reduction position previously stored in the storage device.

According to such a configuration, the displacement mechanism can be controlled based on the previously determined speed reduction position, so it is possible to reduce the process of determining the speed reduction position.

(Section 9) In the scanning probe microscope according to any one of Items 1 to 5, the approach processing section provides feedback until the physical quantity acting between the cantilever and the sample reaches a specified value. The displacement mechanism is controlled by executing the control.

According to such a configuration, the displacement mechanism can be controlled by relatively simple processing.
(Section 10) In the scanning probe microscope according to any one of Items 1 to 5, the cantilever moves in the thickness direction independently of the sample stage.

According to such a configuration, it is possible to improve convenience for the user when placing the sample on the sample stage.

(Section 11) The control method of the present disclosure is a control method of a scanning probe microscope. A scanning probe microscope includes a sample stage on which a sample is placed and a cantilever that scans along the surface of the sample. The relative positions of the sample stage and the cantilever in the thickness direction of the sample are changed. The control method includes acquiring first information regarding the position of the cantilever in the thickness direction, and second information regarding the position of the sample in the thickness direction or the position of the sample stage in the thickness direction. The control method includes changing the relative position of the sample stage and the cantilever at a predetermined approach speed so that the sample stage and the cantilever become close to each other. The control method includes determining a speed reduction position at which the approach speed is switched from high speed to low speed based on the first information and the second information. Changing the relative position includes changing the relative position such that the approach speed is from high to low at the reduced speed position.

Regarding the above-mentioned embodiments and modifications, it is planned from the beginning of the application that the configurations described in the embodiments, including combinations not mentioned in the specification, may be combined as appropriate within the scope of not causing any inconvenience or contradiction. has been done.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that equivalent meanings to the claims and all changes within the range be included.

1 Optical system, 2 Cantilever, 2a Reflecting member, 3 Needle, 3a tip, 4 Holder, 5 Beam splitter, 6 Laser light source, 7 Reflector, 8 Photodetector, 10 Measuring device, 12 Fine movement mechanism, 14 Sample stage, 14a Arrangement surface, 20 Information processing device, 22 Feedback signal generation 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 approach processing unit, 108 storage unit, 108A previous speed reduction position, 110 detection mechanism, 162 ROM, 164 RAM.

Claims

a sample stage on which the sample is placed;
a cantilever scanned along the surface of the sample;
a displacement mechanism that changes the relative position of the sample stage and the cantilever in the thickness direction of the sample;
a detection mechanism that acquires first information that is information regarding the position of the cantilever in the thickness direction, and second information that is information regarding the position of the sample in the thickness direction or the position of the sample stage in the thickness direction;
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;
The approach processing unit is
determining a speed reduction position at which the approach speed is switched from high speed to low speed based on the first information and the second information;
A scanning probe microscope, wherein the displacement mechanism is controlled so that the approach speed changes from high to low at the speed reduction position.
The scanning probe microscope according to claim 1, wherein the second information is information indicating a position of the surface of the sample in the thickness direction.
The sample stage has a placement surface on which the sample is placed,
The second information is information indicating the position of the placement surface in the thickness direction,
The approach processing unit is
Accepting input of thickness information indicating the thickness of the sample from the user,
The scanning probe microscope according to claim 1, wherein the speed reduction position is determined based on the first information, the second information, and the thickness information.
The scanning probe microscope executes a predetermined process for the detection mechanism to acquire the second information,
The scanning probe microscope according to claim 3, wherein the detection mechanism acquires the second information after the predetermined process is executed.
The scanning probe microscope according to claim 4, wherein the predetermined process includes a process of moving the sample stage.
The detection mechanism includes an optical microscope with a constant 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 is
acquiring the first information based on the position of the optical microscope where the distance between the cantilever and the optical microscope is the focal length;
According to any one of claims 1 to 5, the second information is acquired based on the position of the optical microscope where the distance between the sample or the sample stage and the optical microscope is the focal length. scanning probe microscope.
The cantilever is
A reflective member is formed on the opposite side of the portion facing the sample,
Displaced so that the physical quantity acting between the cantilever and the sample is constant,
The scanning probe microscope further includes a light source that irradiates the reflective member with light,
The scanning probe microscope measures the sample based on the reflected light of the light on the reflective member,
The scanning probe microscope according to claim 6, wherein the detection mechanism acquires the first information based on a position of the optical microscope where the distance between the reflecting member and the optical microscope is the focal length.
The scanning probe microscope further includes a storage device that stores the previously determined speed reduction position,
According to any one of claims 1 to 5, the approach processing unit controls the displacement mechanism so that the approach speed changes from high to low at the speed reduction position previously stored in the storage device. The scanning probe microscope described.
Any one of claims 1 to 5, wherein the approach processing unit controls the displacement mechanism by executing feedback control until a physical quantity acting between the cantilever and the sample reaches a specified value. The scanning probe microscope described in Section 1.
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.
A method for controlling a scanning probe microscope, the method comprising:
The scanning probe microscope includes:
a sample stage on which the sample is placed;
a cantilever that is scanned 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:
acquiring first information regarding the position of the cantilever in the thickness direction, and second information regarding 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 approach each other;
determining a speed reduction position for switching the approach speed from high speed to low speed based on the first information and the second information,
Changing the relative position includes changing the relative position such that the approach speed changes from high to low at the speed reduction position.