CN115407086A - Scanning probe microscope and control method - Google Patents

Abstract

The invention provides a scanning probe microscope and a control method. The SPM (100) is used for measuring a sample (S). The SPM (100) is provided with: a sample stage (14) for placing a sample (S); a probe (3) disposed so as to face the sample (S); an inching mechanism (12) that relatively moves the probe (3) along the surface of the sample (S) by performing feedback control so that the atomic force acting between the probe (3) and the sample (S) is constant; and an information processing device (20), wherein the information processing device (20) stops the measurement of the sample (S) when the atomic force is not constant despite the execution of the feedback control.

Description

Scanning probe microscope and control method

Technical Field

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

Background

Conventionally, a Scanning Probe Microscope (SPM) having a Probe that moves relative to the surface of a sample has been proposed. For example, the SPM described in jp 2021-004859 a includes a control device, a sample stage on which a sample is placed, and a probe that moves relative to the sample along the surface of the sample. The SPM measures the sample by driving the sample stage in the X-axis direction, the Y-axis direction, and the Z-axis direction. The control device performs feedback control so that a physical quantity (for example, atomic force) acting between the probe and the sample is constant.

Disclosure of Invention

In the measurement of the sample by the SPM, the following may occur: although the feedback control described above is executed, the physical quantity acting between the probe and the sample is not fixed. This case refers to, for example, a case where the sample has a convex portion that is large enough to make SPM impossible. When the measurement is continued in a state where the sample has the convex portion, there is a possibility that an inaccurate measurement result is obtained.

The present invention has been made to solve the above-described problems, and provides a technique for reducing the possibility of inaccurate measurement results being obtained even when the physical quantity acting between the probe and the sample is not fixed.

The scanning probe microscope of the present disclosure is used to assay a sample. The scanning probe microscope is provided with: a sample stage for placing a sample; a probe disposed so as to face the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by performing a first control so that a physical quantity acting between the probe and the sample is fixed; and a control device that stops measurement of the sample when the physical quantity is not fixed despite execution of the first control.

The control method of the present disclosure is a control method of a scanning probe microscope. The scanning probe microscope is provided with: a sample stage for placing a sample; a probe disposed so as to face the sample; and a first drive mechanism that relatively moves the probe along the surface of the sample. The control method comprises the following steps: executing a first control for fixing a physical quantity acting between the probe and the sample; and stopping the measurement of the sample when the physical quantity is not fixed despite the execution of the first control.

The above objects, features, aspects and advantages of the present invention and other objects, features, aspects and advantages will become apparent from the following detailed description of the present invention, which is to be read in connection with the accompanying drawings.

Drawings

Fig. 1 is a diagram schematically illustrating a configuration of an SPM according to an embodiment.

Fig. 2 is a diagram showing an example of the hardware configuration of the information processing apparatus.

Fig. 3 is a diagram showing an example of the measurement range.

Fig. 4 is a functional block diagram of the information processing apparatus.

Fig. 5 is a diagram illustrating a method of detecting generation of thermal drift.

Fig. 6 is a diagram showing the second control in the case where the sample has an excessively large concave-convex portion.

Fig. 7 is a flowchart for explaining an operation method of the SPM.

Fig. 8 is a flowchart for explaining an operation method of the SPM according to the third embodiment.

Fig. 9 shows an example of a notification text displayed on the display device.

Fig. 10 shows an example of a notification text displayed in the display area of the display device.

Fig. 11 shows an example of a mode selection screen.

Fig. 12 is a diagram for explaining a method of predicting the standby time.

Fig. 13 is a diagram for explaining thermal drift.

Fig. 14 is a flowchart for explaining an operation method of the SPM of the modification.

Fig. 15 is a flowchart of the standby time calculation process.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the drawings. In addition, the same or corresponding portions in the drawings are denoted by the same reference numerals, and description thereof is not repeated.

[ first embodiment ]

Fig. 1 is a diagram schematically showing a structure of a Scanning Probe Microscope (SPM) according to an embodiment. The scanning Probe Microscope 100 according to the present embodiment is typically an Atomic Force Microscope (AFM) that measures the shape of the surface of the sample S by using a physical quantity acting between the Probe (Probe) 3 and the surface of the sample S. The present disclosure can also be applied equally to other Scanning probe microscopes, for example, a Scanning Tunneling Microscope (STM). Further, the physical quantity is, for example, an atomic force (an attractive force or a repulsive force). Hereinafter, the height direction of the sample S is referred to as the Z-axis direction, and the directions orthogonal to the Z-axis direction are referred to as the X-axis direction and the Y-axis direction.

As shown in fig. 1, the scanning probe microscope 100 includes, as main components, a measurement device 10, an information processing device 20, a display device 30, and an input device 40. The measuring apparatus 10 includes, as main components, an optical system 1, a cantilever 2, a fine movement mechanism 12 (scanner), a sample stage 14, a coarse movement mechanism 13, an XY-direction driving unit 16, a Z-direction driving unit 18, and a feedback signal generating unit 22. The "fine movement mechanism 12" of the present embodiment corresponds to the "first drive mechanism" of the present disclosure, and the "coarse movement mechanism 13" of the present embodiment corresponds to the "second drive mechanism" of the present disclosure.

The sample S is disposed on the sample stage 14. The sample stage 14 is disposed on the micro-motion mechanism 12. The micro-motion mechanism 12 is a moving device for changing the relative positional relationship between the sample S and the probe 3. The micro-motion mechanism 12 has 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 finely moves the specimen 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 driving unit 16. The Z scanner 12Z has a piezoelectric element that expands and contracts by a voltage applied from the Z-direction driving unit 18. The Z scanner 12Z extends and contracts by the piezoelectric element. Further, the XY scanner 12XY and the Z scanner 12Z are not limited to the structure having the piezoelectric elements.

In the present embodiment, when the voltage applied by the Z-direction driving unit 18 is the maximum value Vmax, the sample stage 14 is driven to the highest position in the Z-axis direction. When the voltage applied by the Z-direction drive unit 18 is the minimum value Vmin, the sample stage 14 is driven to the lowest position in the Z-axis direction. For example, the maximum value Vmax is + V1 (V1 is a positive real number), and the minimum value Vmin is-V1. When the voltage applied by the Z-direction drive unit 18 is zero, the sample stage 14 is driven to the initial position. In the present embodiment, the initial position is the position at the center in the Z-axis direction. As a modification, when the voltage applied by the Z-direction drive unit 18 is the maximum value Vmax, the sample stage 14 may be driven to the lowest position in the Z-axis direction, and when the voltage is the minimum value Vmin, the sample stage 14 may be driven to the highest position in the Z-axis direction.

The arm 2 is formed in a plate spring shape, and one end thereof is supported by a bracket 4. The other end of the cantilever 2 is a free end, which is arranged to face the sample S. In the example shown in fig. 1, the cantilever 2 is arranged above in the Z-axis direction. The cantilever 2 has a front surface facing the sample S and a back surface located on the opposite side of the front surface. A probe 3 is disposed on the front surface of the tip of the free end of the cantilever 2 so as to face the sample S. The back surface of the tip portion is configured to reflect light. The tip 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.

An optical system 1 for detecting the amount of deflection of the cantilever 2 (i.e., the amount of displacement of the tip portion) is provided above the cantilever 2 in the Z-axis direction. When measuring the sample S, the optical system 1 irradiates a laser beam to the back surface (reflection surface) of the cantilever 2, and detects the laser beam reflected by the reflection surface. Specifically, the optical system 1 includes a laser light source 6, a beam splitter 5, a mirror 7, and a photodetector 8.

The laser light source 6 has a laser oscillator for emitting laser light. The photodetector 8 has a photodiode for detecting the incident laser light. The laser light LA emitted from the laser light source 6 is reflected by the beam splitter 5 and then irradiated to the back surface (reflection surface) of the cantilever 2. The laser light reflected by the back surface of the cantilever 2 is reflected by the mirror 7 and enters the photodetector 8.

The photodetector 8 has a light receiving surface divided into a plurality of (for example, 2) 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 4 in the Z-axis direction and the Y-axis direction. When the tip portion 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, and therefore, the amount of deflection (displacement amount) of the cantilever 2 can be detected based on the plurality of amounts of light received on the plurality of light receiving surfaces.

The feedback signal generating section 22 calculates the amount of deflection of the cantilever 2 by performing arithmetic processing on the detection signal supplied 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 constant. Hereinafter, this control is referred to as "feedback control". In addition, the feedback control corresponds to "first control" of the present disclosure. Specifically, the feedback signal generating section 22 calculates a deviation Sd of the calculated deflection amount of the cantilever 2 from a target value, and calculates a control amount for driving the Z scanner 12Z so that the deviation Sd becomes 0. The feedback signal generating unit 22 calculates a voltage value Vz for displacing the Z scanner 12Z in accordance with the control amount. The feedback signal generating unit 22 outputs a voltage signal indicating the voltage value Vz to the Z-direction driving unit 18. The Z-direction driving section 18 applies a voltage value Vz to the Z scanner 12Z. In this way, the Z-direction driving unit 18 receives 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.

The information processing device 20 calculates a voltage value Vx in the X-axis direction and a voltage value Vy in the Y-axis direction of the XY-direction drive unit 16 so that the sample stage 14 moves relative to the probe 3 in the X-axis and Y-axis directions according to a preset scanning condition, and outputs the voltage values to the XY-direction drive unit 16. The XY-direction driving section 16 applies the voltage values Vx and Vy to the XY scanner 12XY.

The rough movement mechanism 13 moves the sample stage 14 in the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, the structure is: a first movement range in which the sample stage 14 is moved by the micro-movement mechanism 12 is smaller than a second movement range in which the sample stage 14 is moved by the coarse-movement mechanism 13 in the X-axis direction, the Y-axis direction, and the Z-axis direction. Further, the SPM100 may not appropriately measure the sample S for reasons described later. In this case, the coarse movement mechanism 13 executes the backoff process according to the control of the information processing apparatus 20. The retreat process is a process of increasing the distance between the probe 3 and the sample stage 14. The coarse movement mechanism 13 is driven by the information processing device 20.

The information processing device 20 mainly controls the operation of the measurement device 10. Measurement data indicating the feedback amount in the Z-axis direction (the applied voltage Vz applied to the Z scanner 12Z and the deviation Sd) is sent from the Z-direction driving unit 18 to the information processing device 20. The measurement data is transmitted at measurement points determined at predetermined intervals in the Y-axis direction (see fig. 3) of the sample S. The information processing device 20 stores the measurement data. The information processing device 20 calculates the amount of displacement of the sample S in the Z-axis direction from the voltage Vz based on the correlation information stored in advance, which indicates the relationship between the voltage Vz and the amount of displacement of the sample S (sample stage 14) corresponding thereto in the Z-axis direction. The calculated displacement amount is a value reflecting 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 calculates the amount of displacement of the sample S in the Z-axis direction for each position in the X-axis and Y-axis directions within the scanning range, thereby creating two-dimensional or three-dimensional measurement data indicating the shape of the surface of the sample S. 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 measurement data.

The image data created by the information processing device 20 includes a value (Z value) indicating a position in the Z axis direction at each position on the XY plane. The Z value corresponds to the height of the surface at each position on the sample stage 14, and the Z value at the position where the sample S exists corresponds to the height including the sample S. The information processing device 20 displays the created image data on the display device 30. In addition, the user inputs various information from the input device 40.

[ hardware configuration of information processing apparatus ]

Fig. 2 is a diagram showing an example of the hardware configuration of the information processing apparatus 20. Referring to fig. 2, the information Processing apparatus 20 includes, as main constituent elements, a CPU (Central Processing Unit) 160, a ROM (Read Only Memory) 162, a RAM (Random Access Memory) 164, an HDD (Hard Disk Drive) 166, a communication I/F (Interface) 168, a display I/F170, and an input I/F172. The respective components are connected to each other by a data bus. At least a part 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 scanning probe microscope 100, and may be configured to perform bidirectional communication with the scanning probe microscope 100.

The communication I/F168 is an interface for communicating with the measurement device 10. The display I/F170 is an interface for communicating with the display device 30. The input I/F172 is an interface for communicating with the input device 40.

The ROM162 is used to store programs executed by the CPU 160. The RAM 164 can temporarily hold data generated by the CPU 160 executing programs and data input via the communication I/F168. The RAM 164 can function as a temporary data storage used as a work area. The HDD 166 is a nonvolatile storage device. Instead of the HDD 166, a semiconductor memory device such as a flash memory may be used.

The program stored in the ROM162 may be stored in a storage medium and distributed as a program product. Alternatively, the program may be provided by an information provider as a product program that can be downloaded via the so-called internet or the like. The information processing apparatus 20 reads a program provided by a storage medium, the internet, or the like. The information processing device 20 stores the read program in a predetermined storage area (for example, the ROM 162). The CPU 160 can execute the program to execute the image data acquisition process described later.

The display device 30 can display a setting screen for setting the acquisition condition of the image data. In addition, the display device 30 can display the image data created by the information processing device 20 and the data obtained by processing the image data in the process of acquiring the image data.

The input device 40 accepts an input from a user (e.g., an analyst) including an instruction for the information processing device 20. The input device 40 includes a keyboard, a mouse, a touch panel integrally configured with the display screen of the display device 30, and the like, and the input device 40 is used to accept acquisition conditions of images and the like.

[ measurement Range of sample S ]

The user can input the measurement range of the sample S from the input device 40. Fig. 3 is a diagram showing an example of the measurement range R1. In the example of fig. 3, the measurement range R1 is set in a rectangular shape. As shown in fig. 3, the information processing device 20 relatively moves the probe 3 in a reciprocating manner along a measurement path L (a path in the first row) of the sample S in the Y-axis direction. In the example of fig. 3, the positive direction of the Y axis corresponds to the "first direction" of the present disclosure, and the negative direction of the Y axis corresponds to the "second direction" of the present disclosure. When the reciprocating movement of the probe 3 in the measurement path L is completed, the probe 3 performs a predetermined amount of relative movement in the X-axis direction. Then, the probe 3 is relatively moved in a reciprocating manner again in the next measurement path (path of the second row). In this way, the probe 3 reciprocates over the entire range of the measurement range R1. Further, as a modification, the probe 3 may be reciprocated in the X-axis direction.

[ processing of information processing apparatus ]

Fig. 4 is a functional block diagram of the information processing apparatus 20. The information processing device 20 includes an input unit 102, a processing unit 104, a driving unit 106, and a storage unit 108. The input unit 102 receives measurement data (applied voltage Vz and deviation Sd) from the Z-direction driving unit 18. The measurement data is output to the processing unit 104. The processing unit 104 creates measurement data by calculating the amount of displacement of the sample S in the Z-axis direction. Here, data generated by the processing unit 104 when the probe 3 is relatively moved in the first direction is referred to as "first measurement data". The first measurement data is measurement data during the outbound route. The data created by the processing unit 104 when the probe 3 is relatively moved in the second direction is referred to as "second measurement data". The second measurement data is measurement data in the return trip. In this way, the processing unit 104 creates the first measurement data and the second measurement data.

Further, the processing unit 104 determines whether the deviation Sd is 0. In the measurement of the sample S, when the sample S is in a normal state, the above-described feedback control is executed to set the deviation Sd to 0. However, the deviation Sd may not become 0 for the following reasons. The reason includes a first reason and a second reason.

The first cause is the presence of an excessively large uneven portion described later in the sample S. The excessively large uneven portion means an excessively high convex portion and an excessively deep concave portion. The excessively high convex portion has a height in the Z-axis direction longer than the first movement range (the movement range in which the sample stage 14 is moved by the micro-movement mechanism 12). The excessively deep recess is a recess having a depth in the Z-axis direction longer than the first movement range. Here, the first movement range in which the sample stage 14 is moved by the micro-movement mechanism 12 is several μm to several tens of μm.

The second cause is such that thermal drift is generated. The thermal drift is generated by heat generated from the SPM100 or the sample S during the measurement of the sample S by the SPM 100. Due to thermal drift of the SPM100 apparatus as a whole, unexpected changes in the relative position between the probe 3 and the sample S may occur.

The unexpected change in the relative position between the probe 3 and the sample S may be a case where the probe 3 approaches the sample S with the passage of time, or a case where the probe 3 moves away from the sample S with the passage of time. For example, when thermal drift occurs in the direction in which the probe 3 approaches the sample S, the following phenomenon may occur: when the measurement of the sample S is continued, the deviation Sd does not become 0 even if the Z scanner 12Z is in a completely contracted state. In contrast, when thermal drift occurs in the direction in which the probe 3 is away from the sample S, the following phenomenon may occur: even if the Z scanner 12Z is in a fully extended state, the deviation Sd does not become 0. That is, since the voltage applied to the Z scanner 12Z by the Z-direction driving unit 18 is in a state of the maximum value Vmax or a state of the minimum value Vmin due to the occurrence of the thermal drift, the deviation Sd does not become 0 (the atomic force is not fixed) although the above-described feedback control is performed. Such a state is referred to as a "state in which an influence due to thermal drift beyond the operating range of the micro-motion mechanism 12 is generated".

Hereinafter, the "thermal drift that acts so that the probe 3 approaches the sample S with the passage of time" is also referred to as a "first thermal drift". The "thermal drift that acts so as to separate the probe 3 from the sample S with the passage of time" is also referred to as "second thermal drift". In addition, when thermal drift occurs, the type of the thermal drift does not change from the middle. For example, when the first thermal drift occurs, the second thermal drift does not occur from the middle. Further, when the second thermal drift occurs, the first thermal drift does not occur from the middle.

Next, a method of determining the type of cause (which is the first cause or the second cause) will be described. When determining that the deviation Sd is not 0, the processing unit 104 acquires the measurement data (measurement data acquired in the past) stored in the storage unit 108. For example, the processing unit 104 acquires N pieces of measurement data that have been stored recently (acquired recently). N is an integer of 1 or more. Each of the N measurement data includes first measurement data and second measurement data. Then, the processing unit 104 specifies the type of cause based on the measurement data.

Fig. 5 shows an example of the past measurement data. In fig. 5 (a) to 5 (C), the horizontal axis represents time t, and the vertical axis represents the height of the sample S measured by the SPM 10. Fig. 5 shows measurement data of the forward travel and measurement data of the backward travel. The start time of the measurement of the forward travel is set to "t0", the reverse time of the reverse from the forward travel to the reverse travel is set to "t1", and the end time of the measurement of the reverse travel is set to "t2". In the example of fig. 5, for convenience, when the forward measurement is reversed to the backward measurement, the end time of the forward measurement and the start time of the backward measurement are the same, but the end time of the forward measurement and the start time of the backward measurement may be different.

The processing unit 104 converts the measurement data during the return to inverse data (third measurement data) obtained by inverting the time series of the measurement data during the return. Then, the processing unit 104 calculates the degree of coincidence between the forward measurement data (first measurement data) and the backward measurement data corresponding to the return stroke. The coincidence degree is a value indicating the degree of coincidence between the forward measurement data and the reverse measurement data. The degree of coincidence is calculated based on, for example, the average value or standard deviation of the differences between the values indicated by the measurement data at the plurality of identical positions of the sample S between the forward measurement data and the backward measurement data.

Fig. 5 (a) is a diagram for explaining the cause (i.e., the first cause) that an excessively large uneven portion exists without generating thermal drift. As shown in fig. 5 a, the measurement data of the forward measurement period matches the reverse data (the degree of matching is equal to or greater than the threshold). Therefore, when the processing unit 104 acquires the past measurement data shown in fig. 5 (a) when the deviation Sd is not 0, it is determined as the first cause.

Fig. 5 (B) shows a case where thermal drift (first thermal drift) that acts to bring the probe 3 close to the sample S occurs. In fig. 5 (B), the measurement data of the return path is data indicating that the probe 3 and the sample S are close to each other due to the influence of the first thermal drift.

Fig. 5C shows a case where thermal drift (second thermal drift) that acts to separate the probe 3 from the sample S occurs. In fig. 5 (C), the measurement data of the return path is data indicating that the probe 3 and the sample S are separated from each other by the influence of the second thermal drift. In the return process of fig. 5 (B) and 5 (C), a waveform (normal waveform) when no thermal drift occurs is indicated by a broken line.

The measurement data in fig. 5 is an example. For example, according to the configuration of the SPM100, the measurement data in fig. 5 (C) may be acquired when the first thermal drift occurs, and the measurement data in fig. 5 (B) may be acquired when the second thermal drift occurs.

As shown in fig. 5 (B) and 5 (C), the measurement data during the forward measurement period does not match the reverse data (the degree of matching is less than the threshold). Therefore, when the past measurement data shown in fig. 5B is acquired when the deviation Sd is not 0, the processing unit 104 identifies the second cause (occurrence of the first thermal drift). When the past measurement data shown in fig. 5C is acquired when the deviation Sd is not 0, the processing unit 104 identifies the second cause (occurrence of the second thermal drift).

When specifying the type of the cause, the processing unit 104 causes the storage unit 108 to store a flag (cause information) that enables specifying the type of the cause. When the first cause is specified, the processing unit 104 causes the storage unit 108 to store the concave-convex flag. The concave-convex portion flag is a flag indicating that an excessively large concave-convex portion is detected. When the second cause is specified, the processing unit 104 causes the storage unit 108 to store the thermal drift flag. The thermal drift flag is a flag indicating that thermal drift is detected. When the first cause or the second cause is specified, the processing unit 104 transmits a cause signal indicating the specified cause to the measuring apparatus 10. The measuring apparatus 10 can identify the cause by receiving the cause signal.

In addition, when the sample S has an excessively large uneven portion as a first cause, there are cases where: the SPM100 cannot properly measure the sample S, and at least one of the sample S and the probe 3 is damaged by the contact of the sample S with the probe 3 when the measurement is continued. Therefore, the SPM100 of the present embodiment executes the second control for eliminating the influence of the first factor, and continues the measurement after the second control.

Fig. 6 is a diagram showing second control for eliminating the influence of the first cause. Fig. 6 shows a sample S and a measurement range R1 set by a user. As shown in fig. 6 a, the deviation Sd is not 0 at the portion α (a special projection is present). In this case, the driving unit 106 drives the coarse movement mechanism 13 to perform a retraction process (a process of increasing the distance between the probe 3 and the sample stage 14 (sample S)). Thus, the SPM100 can prevent the probe 3 from colliding with the sample S. The measurement device 10 sets the voltage applied from the Z-direction driving unit 18 to the Z scanner 12Z to zero. This is because the Z scanner 12Z is highly likely to be completely contracted or completely expanded to follow the shape of the large concave-convex portion. As shown in fig. 6 (B), the processing unit 104 changes the measurement range from the measurement range R1 to a new measurement range R2. The driving unit 106 drives the coarse movement mechanism 13 to move the sample stage 14 so as to be able to measure the new measurement range R2. Then, the measurement device 10 resumes the measurement of the sample S within the measurement range R2. Since the voltage applied from the Z-direction driving unit 18 to the Z scanner is set to zero, the sample stage 14 is driven to the initial position. Therefore, the SPM100 can reduce the collision between the probe 3 and the sample stage 14 and can measure the measurement range R2 with a margin in the expansion/contraction range of the Z scanner 12Z.

Here, the measurement range R2 is a range excluding the portion α, that is, a measurement range excluding the portion α where the atomic force is not fixed, and is preferably the same area as the area of the measurement range R1. More specifically, the measurement range R2 is a range adjacent to the portion α. "adjacent to the portion α" may mean "the portion α is present in a frame forming the measurement range R2". The phrase "adjacent to the portion α" may mean "a predetermined distance from a frame forming the measurement range R2". Further, the information processing device 20 stores the XY coordinates of the portion α in which the first cause has occurred. Then, the information processing device 20 newly sets the measurement range R2 with reference to the XY coordinates of the portion α.

When the first cause is again generated in the new measurement range R2, a new measurement range excluding the portion α in which the first cause is again generated is set. In this way, the SPM100 repeats the resetting of the measurement range until the measurement within the measurement range is completed without causing the first cause. In addition, in the case where the measurement range in which the first cause does not occur cannot be set in the sample S even though the resetting of the measurement range is performed a plurality of times, the SPM100 determines that the measurement for the sample S cannot be performed and ends the measurement process. Therefore, the information processing device 20 executes a notification indicating that the measurement cannot be performed.

In addition, when thermal drift occurs as a second cause, the SPM100 cannot appropriately measure the sample S. Therefore, the SPM100 of the present embodiment executes the second control for reducing the influence of the second factor, and continues the measurement after the second control.

It is assumed that the deviation Sd does not become 0 in the measurement of the sample S (influence due to thermal drift exceeding the operating range of the fine movement mechanism 12 occurs). In this case, the driving unit 106 needs to execute a retraction process (a process of increasing the distance between the probe 3 and the sample stage 14 (sample S)) by driving the coarse movement mechanism 13. The second control for eliminating the first cause and the second cause includes the backoff process. This prevents the probe 3 from colliding with the sample S. Then, the measurement device 10 sets the applied voltage applied to the Z scanner 12Z to zero. As described above, in the "state in which the influence due to the thermal drift beyond the operating range of the fine movement mechanism 12 is generated", the voltage applied to the Z scanner 12Z by the Z-direction driving unit 18 is in the state of the maximum value Vmax or the state of the minimum value Vmin, and therefore, the voltage is adjusted to 0. The second control for eliminating the first cause and the second cause includes a process of setting the applied voltage to zero. Then, the driving unit 106 drives the coarse movement mechanism 13 to bring the probe 3 closer to the sample S again, and resumes the measurement of the sample S within the measurement range R1. Since the voltage applied from the Z-direction driving unit 18 to the Z scanner is set to 0, the Z scanner 12Z can expand and contract again.

[ method of operation of SPM ]

Fig. 7 is a flowchart for explaining an operation method of the SPM 100. The processing of fig. 7 is executed for each measurement point within the set measurement range.

In step S2, the SPM100 acquires the deviation Sd. Next, in step S4, the SPM100 drives the Z scanner 12Z by performing feedback control so as to become Sd =0. Next, in step S5, the SPM100 determines whether Sd =0. When Sd =0 is obtained, in step S21, the SPM100 causes the storage unit 108 to store the measurement data obtained when Sd =0 is determined. Next, in step S22, the SPM100 determines whether or not the measurement of the sample S is finished. If yes is determined in S22, the process ends. On the other hand, in step S22, if the determination is no, the process returns to step S2.

When the determination in step S5 is no, the SPM100 temporarily stops the measurement in step S6. Next, in step S7, the SPM100 drives the coarse movement mechanism 13 to retract the sample stage 14 from the cantilever 2. Then, in S8, the SPM100 sets the applied voltage applied from the Z-direction driving unit 18 to the Z scanner 12 to zero. In step S9, the SPM100 determines the cause of the Sd =0 failure.

Fig. 8 is a diagram for explaining the cause determination processing in step S9. In step S72, the SPM100 determines whether or not the measurement data is stored in the storage unit 108. Here, the measurement data is measurement data of the sample S after the process of fig. 7 is started. When there is no measurement data (for example, when the measurement in the first row is not completed), the SPM100 cannot identify the cause. Therefore, if the measurement data is not stored in the storage unit 108 in step S72 (no in step S72), the SPM100 stops the measurement in step S82, and then the process ends. In addition, the SPM100 may notify the user of the content of the completed processing.

On the other hand, if it is determined yes in step S72, the process proceeds to step S74. In step S74, the SPM100 generates the inverse data described above. Next, in step S76, it is determined whether or not the degree of coincidence between the forward data and the generated inverse data is equal to or greater than a threshold value (see the description of fig. 5).

If it is determined "yes" in step S76 (that is, in the case of fig. 5 a), in step S78, the SPM100 detects an excessively large uneven portion (specifies the first cause). On the other hand, in the case where the determination in step S76 is "no" (that is, in the case of fig. 5 (B) or fig. 5 (C)), the SPM100 detects the thermal drift in step S80 (specifies the second cause).

The description returns to fig. 7. When the processing in step S9 ends, the SPM100 determines the identified cause in step S10. If the cause is an excessively large uneven portion, the process proceeds to step S11, and if the cause is thermal drift, the process proceeds to step S16.

In step S11, the SPM100 stores the jog flag in a predetermined storage area (e.g., the RAM 164 shown in fig. 2). Next, in step S12, the SPM100 sets a new measurement range R2 excluding the portion having the excessively large uneven portion (that is, the portion determined in step S5 not to have the deviation Sd = 0) (see fig. 6). Next, in step S14, the SPM100 resumes the measurement of the sample S within the new measurement range R2, and the process returns to step S2.

In addition, in step S16, the SPM100 stores a thermal drift flag. Next, in step S20, the SPM100 drives the coarse movement mechanism 13 again to bring the probe 3 close to the sample stage 14 (sample S), resumes the measurement of the sample S within the measurement range R1, and returns the process to step S2.

In the measurement of a sample by a conventional SPM, there are cases where: although the above-described feedback control is performed, the atomic force does not become fixed. This case is, for example, a case where the sample has a convex portion large enough to make SPM impossible. When the measurement is continued in a state where the sample has the convex portion, there is a possibility that a problem of obtaining an inaccurate measurement result occurs.

Therefore, if Sd =0 is not satisfied (no in step S5), the SPM100 stops the measurement in step S6. Thus, the SPM100 can reduce the situation where inaccurate measurement results are obtained.

Further, if the SPM is kept in a state in which the measurement of the sample is stopped, there is a possibility that the measurement completion time of the sample is delayed.

In addition, for example, the SPM100 may perform measurement for a long time. The measurement requiring a long time includes, for example, measurement at a high pixel, measurement at a slow scanning speed, measurement of a plurality of samples, and the like. There are the following situations: in the case of such a measurement requiring a long time, the user is located at a place distant from the SPM 100. In this case, there is a fear that: when the user accidentally stops the measurement of the sample, the user does not notice the stop of the measurement and a long time elapses. In addition, the measurement needs to be restarted, which increases the burden on the user.

On the other hand, when the atomic force is not constant, the SPM100 stops the measurement of the sample S, then executes the second control, and restarts the measurement of the sample after the execution of the second control (see step S14 and step S20 in fig. 7). The second control is a control for reducing an influence of the cause of the occurrence. In the present embodiment, the second control is, for example, step S7, step S8, and the like. Then, the SPM100 resumes the measurement of the sample after executing the second control (step S14 and step S20). Therefore, the SPM100 can restart the measurement of the sample S after eliminating the cause of not becoming Sd =0. This reduces the occurrence of delay in the measurement of the sample for the user. Further, the user does not need to perform the operation of measuring the sample S again with the SPM100, and as a result, the burden on the user can be reduced.

The second control includes a retraction process of the sample stage 14 (step S7). Therefore, the collision of the probe 3 with the sample stage 14 can be reduced.

The second control includes a process of setting the applied voltage applied to the Z scanner 12Z to zero. Thus, the specimen stage 14 is driven to the initial position. Thus, the SPM100 can reduce the collision between the probe 3 and the sample stage 14, and can measure the measurement range R2 with a margin in the expansion/contraction range of the Z scanner 12Z.

The SPM100 identifies the cause based on the first measurement data and the second measurement data in the past (see fig. 8). Thus, the SPM100 can determine that atomic force is not the cause of the fixation.

In addition, in the case where the degree of coincidence between the forward data and the backward data described above is higher than the threshold value, the SPM100 stores the concavo-convex flag and executes the control of step S12 as the second control. The control in step S12 is control for setting the measurement range of the sample S to a measurement range excluding a portion where the atomic force is not fixed. Therefore, the SPM100 can measure the portion of the sample S other than the special convex portion by setting the measurement range R1 of the sample S to the measurement range R2 excluding the portion α.

As shown in fig. 6, the newly set measurement range R2 is a range adjacent to a portion α where the special convex portion exists (a portion where the deviation Sd does not become 0 despite the feedback control is performed). Therefore, the amount of movement in the XY plane when the measurement range is changed can be minimized.

When the first measurement data and the second measurement data are not acquired (no in step S72 in fig. 8), the SPM100 stops the measurement of the sample (step S82). Therefore, it is possible to prevent the measurement of the sample S from being continued in a state where the cause Sd is not 0 cannot be identified.

[ other embodiments ]

(1) The information processing apparatus 20 may also perform notification based on the specified reason (the type of the stored flag). For example, when the first cause is specified (when the measurement range R1 is set as the measurement range R2), the user may be notified of the first cause by the display device 30. Fig. 9 shows an example of the notification text displayed in the display area 30A of the display device 30. In the example of fig. 9, a notification text 140 indicating that "the measurement range has been changed because of the presence of the non-measurable convex portion or concave portion" is displayed. The notification is performed at a predetermined timing after the first cause is generated. The predetermined time is, for example, the time when the measurement of the sample S within the measurement range R2 is completed. Thus, the SPM100 can make the user recognize that there is a convex portion or a concave portion that cannot be measured within the measurement range and that the measurement range has been changed.

In addition, the information processing apparatus 20 may notify the user by using the display apparatus 30 when the second cause occurs. Fig. 10 shows an example of the notification text displayed in the display area 30A of the display device 30. The notification text 150 of fig. 10 is a text of "thermal drift is generated". With such notification, the SPM100 is able to identify to the user that thermal drift has occurred.

(2) In fig. 6, the following structure is illustrated: when the special convex portion or the special concave portion of the sample S is detected, the SPM100 automatically changes the measurement range. However, the user may not desire to change the measurement range in this manner. In this regard, the SPM100 may be configured to enable the user to select the automatic measurement mode or the stop mode. The automatic measurement mode is a mode in which the measurement of the sample S is restarted after the measurement of the sample S is stopped. The stop mode is a mode in which the measurement of the sample S is not restarted after the measurement of the sample S is stopped. The automatic measurement mode corresponds to the "first mode" of the present disclosure, and the stop mode corresponds to the "second mode" of the present disclosure.

Fig. 11 shows an example of a mode selection screen. The selection screen is displayed in the display area 30A of the display device 30. The selection screen includes a text 190 such as "please select the mode", an option 192 for the automatic measurement mode, and an option 194 for the stop mode.

The user can set the mode by checking a check box of a desired selection item. The user checks the check box using, for example, the input device 40. The SPM100 accepts input of selection of a mode from a user to set the selected mode. In this way, the user can select either the stop mode or the automatic measurement mode, and therefore, the user's convenience can be improved.

(3) In fig. 7, the following structure is illustrated: when the thermal drift occurs, the measurement is restarted in step S20 immediately after the applied voltage applied to the Z scanner 12Z is reset to 0 in step S8. However, if the measurement is immediately resumed, the influence of the thermal drift of the entire SPM100 may remain, and the relative position between the probe 3 and the sample S may be unexpectedly changed due to the influence of the thermal drift beyond the operating range of the micro-motion mechanism 12.

Therefore, a standby time for reducing or eliminating the thermal drift of the entire SPM100 may be set before the measurement of the sample S is restarted. In this way, the second control when the thermal drift occurs includes a process of stopping the measurement of the sample S for the entire standby time.

In this modification, a method of calculating the standby time will be described. Generally, when thermal drift occurs, the amount of thermal drift (the degree of influence of thermal drift) decreases with the passage of time from the occurrence of the thermal drift (see curve a in fig. 12). The SPM100 of this modification calculates (or estimates) the standby time based on this phenomenon.

Fig. 12 is a diagram for explaining a method of predicting the standby time. As shown in fig. 12, the thermal drift amount M1 at time t11, the thermal drift amount M2 at time t12, the flag A1, and the flag A2 are shown. Also, curve a is shown, which represents a function of the standby time versus the thermal drift.

The information processing apparatus 20 creates a curve a of the function based on the thermal drift amount M1, the thermal drift amount M2, and the elapsed time T0. More specifically, the information processing apparatus 20 calculates the difference Δ M between the thermal drift amount M1 and the thermal drift amount M2. Then, the information processing apparatus 20 calculates the rate of change in the amount of thermal drift by dividing the difference Δ M by the elapsed time T0. Then, a curve a of the function is created based on the rate of change. The formula of the function is stored in the storage unit 108, for example.

Then, the information processing device 20 calculates, as the standby time, the time T1 until the thermal drift amount becomes the minimum value M0 (time T13) based on the curve a. The start time of the standby time T1 is, for example, the time at which the calculation of the standby time T1 is completed.

Fig. 13 is a diagram for explaining the amount of thermal drift M1 and the amount of thermal drift M2. The information processing device 20 uses past measurement data of 2 or more measurement paths (2 or more lines). As shown in fig. 13 a, the information processing device 20 calculates a first measurement difference value M1a based on first measurement data (forward measurement data) and second measurement data (backward measurement data) on a first measurement path (first row in the example of fig. 13) of the sample S. Specifically, the information processing device 20 calculates inverse data of the forward stroke (data obtained by inverting the time series). In fig. 13 (a), backward data of the forward stroke is indicated by a dotted line. Then, the information processing device 20 calculates a first measurement differential value M1a, which is a differential value between the reverse data and the return data. The first measurement difference value M1a is a value corresponding to the amount of thermal drift. The larger the amount of thermal drift, the larger the measurement difference value. The information processing device 20 calculates the thermal drift amount M1 by multiplying the first measurement difference value M1a by a predetermined coefficient C. The coefficient C is a real number and can be set to 1.

As shown in fig. 13B, the information processing device 20 calculates a second measurement difference value M2a based on the first measurement data (forward measurement data) and the second measurement data (backward measurement data) on the second measurement path (the second row in the example of fig. 13) of the sample S. Specifically, the information processing device 20 calculates inverse data of the forward stroke (data obtained by inverting the time series). In fig. 13 (B), backward data of the forward stroke is indicated by a dotted line. Then, the information processing device 20 calculates a second measurement difference value M2a that is a difference value between the reverse data and the return data. The second measurement difference value M2a is a value corresponding to the amount of thermal drift. As described above, in general, when thermal drift occurs, the amount of thermal drift decreases with the passage of time from the occurrence of the thermal drift. Therefore, the second measurement difference value M2a is smaller than the first measurement difference value M1a. The information processing device 20 calculates the thermal drift amount M2 by multiplying the second measurement difference value M2a by the coefficient C.

The information processing device 20 acquires an elapsed time T0 from the time when the relative reciprocating movement of the probe 3 in the first measurement path ends (time T11 in fig. 12) to the time when the relative reciprocating movement of the probe in the second measurement path ends (time T12 in fig. 12). The information processing device 20 can acquire the elapsed time T0 from the scanning speed of the probe 3, the measured number of pixels, and the like. In addition, the information processing apparatus 20 may also have a timer for measuring the elapsed time T0.

Then, the information processing device 20 creates a curve a based on the thermal drift amount M1 (the value calculated from the first measurement difference value M1 a), the thermal drift amount M2 (the value calculated from the second measurement difference value M2 a), and the elapsed time T0, and calculates the standby time T1 using the curve a.

Fig. 14 is a flowchart for explaining an operation method of the SPM according to this modification. In the flowchart of fig. 14, step S17 and step S18 are added between step S16 and step S20 in the flowchart of fig. 7.

When the process of step S16 ends, the SPM100 calculates the standby time T1 in step S17. Next, in step S18, the SPM100 determines whether the standby time T1 has elapsed. The SPM100 executes the process of stopping the measurement of the sample S for the entire standby time as the second control described above (no in step S18). When the standby time T1 elapses (yes in step S18), the SPM100 resumes the measurement of the sample S in step S20.

Fig. 15 is a flowchart of the standby time calculation process of step S17. In step S102, SPM100 calculates a first measurement difference value M1a based on the first measurement data and the second measurement data on the first measurement path in the past. Next, in step S104, the SPM100 calculates a second measurement difference value M2a based on the first measurement data and the second measurement data on the second measurement path in the past.

Next, in step S106, the SPM100 acquires the elapsed time T0. Then, the SPM100 calculates the standby time T1 by making a curve a. In this modification, as shown in fig. 12, the standby time T1 is calculated using data of 2 flags (flag A1 and flag A2), but the curve a may be calculated using data of 3 or more flags.

According to this modification, the SPM100 can calculate the standby time T1 corresponding to the amount of generated thermal drift. Further, since the SPM100 restarts the measurement of the sample S after the standby time T1 has elapsed, the measurement with the influence of the thermal drift reduced on the sample S can be performed.

In the modification, the SPM100 calculates the standby time T1, but the standby time T1 may be a predetermined time. The predetermined time is, for example, 1 hour. The standby time T1 may be set by a user. Even with such a configuration, since the SPM100 restarts the measurement of the sample S after the standby time T1 has elapsed, the measurement with the influence of the thermal drift reduced on the sample S can be performed.

[ means ]

It should be understood by those skilled in the art that the various exemplary embodiments described above are specific examples in the following manner.

A scanning probe microscope according to (a first aspect) of the present invention is a scanning probe microscope for measuring a sample, including: a sample stage for placing a sample; a probe disposed so as to face the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by performing a first control so that a physical quantity acting between the probe and the sample is fixed; and a control device that stops the measurement of the sample when the physical quantity is not fixed despite execution of the first control.

According to such a configuration, even when the physical quantity acting between the probe and the sample is not fixed, the measurement of the sample is stopped, and therefore, it is possible to reduce the possibility of inaccurate measurement results being obtained.

(second item) in the scanning probe microscope according to the first item, when the physical quantity is not fixed, the control device executes the second control after stopping the measurement of the sample, and the control device restarts the measurement of the sample after executing the second control.

With this configuration, even when the physical quantity acting between the probe and the sample is not fixed, the measurement of the sample can be resumed.

The scanning probe microscope according to the second aspect (third aspect) further includes a second drive mechanism that executes a retraction process for increasing a distance between the probe and the sample stage, and the second control includes the retraction process.

According to such a configuration, when the physical quantity acting between the probe and the sample is not fixed, the retreat process for increasing the distance between the probe and the sample stage is executed, and therefore, the collision between the probe and the sample stage can be reduced.

(fourth) in the scanning probe microscope according to the second or third aspect, the first driving mechanism performs: the sample stage is driven in accordance with the applied voltage, and when the applied voltage is zero, the sample stage is driven to the initial position, and the second control includes a process of setting the voltage applied to the first drive mechanism to zero.

According to such a configuration, since the sample stage can be driven to the initial position when the physical quantity acting between the probe and the sample is not fixed, it is possible to reduce collision between the probe and the sample stage when measurement of the sample is resumed.

(fifth item) the scanning probe microscope according to any one of the second to fourth items, wherein the control device performs: the method includes the steps of relatively moving a probe in a first direction and a second direction in a same measurement path of the sample, the first direction and the second direction being orthogonal to the height direction of the sample, the second direction being a direction opposite to the first direction, acquiring measurement data of the sample, storing the first measurement data acquired by the movement of the probe in the first direction in the same measurement path and the second measurement data acquired by the movement of the probe in the second direction in the same measurement path, determining, when the physical quantity is not fixed, a cause for which the physical quantity is not fixed based on the stored first measurement data and second measurement data, and storing cause information enabling the determination of the determined cause.

With this configuration, the cause information can be identified based on the first measurement data and the second measurement data.

(sixth item) in the scanning probe microscope according to the fifth item, the control device executes, as the second control, control of setting the measurement range of the sample to a measurement range excluding a portion where the physical quantity is not fixed, when a degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is equal to or greater than a threshold value.

According to such a configuration, when the above-described coincidence degree is equal to or higher than the threshold value, there is a high possibility that a convex portion or a concave portion that cannot be measured by the scanning probe microscope exists in the sample. Since the measurement cannot be performed within the measurement range including the portion where the convex portion or the concave portion exists, the sample can be appropriately measured by setting the measurement range excluding the portion where the convex portion or the concave portion exists.

(seventh) the scanning probe microscope according to the sixth aspect, wherein the measurement range is set to a range adjacent to the site.

With this configuration, the driving amount of the first driving mechanism in the changing range can be minimized.

(eighth) the scanning probe microscope according to any one of the fifth to seventh controls, wherein the control device executes a process of stopping the measurement of the sample for a predetermined standby time as the second control when a degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is less than a threshold value.

According to this configuration, since the scanning probe microscope restarts the measurement of the sample after the standby time has elapsed, the measurement with the influence of the thermal drift reduced on the sample S can be performed.

(ninth aspect) the scanning probe microscope according to any one of the fifth to seventh aspects, wherein the control device performs, as the second control, a process of, when a degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is less than a threshold value: calculating a first measurement difference value based on the first measurement data and the second measurement data on a first measurement path of the sample, calculating a second measurement difference value based on the first measurement data and the second measurement data on a second measurement path of the sample, acquiring an elapsed time from a time when a relative reciprocating movement of the probe in the first measurement path ends to a time when the relative reciprocating movement of the probe in the second measurement path ends, calculating a standby time based on the first measurement difference value, the second measurement difference value, and the elapsed time, and stopping the measurement of the sample for the entire calculated standby time.

With this configuration, the standby time corresponding to the amount of generated thermal drift can be calculated. Further, since the scanning probe microscope restarts the measurement of the sample after the standby time has elapsed, the measurement with the influence of the thermal drift reduced can be performed on the sample S.

(tenth) in the scanning probe microscope according to any one of the fifth to ninth aspects, the control device stops the measurement of the sample when the first measurement data and the second measurement data are not stored.

With this configuration, the cause cannot be specified when the first measurement data and the second measurement data are not stored, for example, when the 1 reciprocation is not completed. In this case, since the measurement of the sample can be stopped, safety can be ensured.

The scanning probe microscope according to any one of the fifth to tenth items (eleventh item), wherein the control device executes a notification based on the cause information.

With this configuration, the user can recognize the content whose cause has occurred.

(twelfth item) the scanning probe microscope according to any one of the second to eleventh items, wherein the control device is capable of switching the following modes in response to a user input: a first mode in which measurement of the sample is resumed after the measurement of the sample is stopped; and a second mode in which measurement of the sample is not resumed after the measurement of the sample is stopped.

With this configuration, the user can select either one of the first mode in which the measurement of the sample is resumed after the measurement of the sample is stopped, and the second mode in which the measurement of the sample is not resumed after the measurement of the sample is stopped.

A control method according to another aspect (thirteenth aspect) is a control method for a scanning probe microscope for measuring a sample, the scanning probe microscope including: a sample stage for placing a sample; a probe disposed so as to face the sample; and a first drive mechanism that relatively moves the probe along the surface of the sample, the control method including: executing a first control for fixing a physical quantity acting between the probe and the sample; and stopping the measurement of the sample when the physical quantity is not fixed despite the execution of the first control.

According to such a configuration, even when the physical quantity acting between the probe and the sample is not fixed, the measurement of the sample is stopped, and therefore, it is possible to reduce the possibility of inaccurate measurement results being obtained.

Further, with respect to the above-described embodiment and modification, the following is intended from the original application: including combinations not mentioned in the specification, can be combined appropriately with the structures described in the embodiments within a range not causing an inconvenience or a contradiction.

While the embodiments of the present invention have been described, it should be understood that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims (13)

1. A scanning probe microscope for measuring a sample, comprising:

a sample stage for placing the sample;

a probe disposed so as to face the sample;

a first drive mechanism that relatively moves the probe along the surface of the sample by performing a first control so that a physical quantity acting between the probe and the sample is fixed; and

and a control device that stops the measurement of the sample when the physical quantity is not fixed despite the execution of the first control.

2. The scanning probe microscope of claim 1,

the control device executes a second control after stopping the measurement of the sample when the physical quantity is not fixed,

the control device resumes the measurement of the sample after executing the second control.

3. The scanning probe microscope of claim 2,

the scanning probe microscope further includes a second drive mechanism that executes a retreat process for increasing a distance between the probe and the sample stage,

the second control includes the backoff process.

4. The scanning probe microscope of claim 2 or 3,

the first driving mechanism performs the following processes:

the specimen stage is driven according to the applied voltage,

the second control includes a process of setting the voltage applied to the first drive mechanism to zero.

5. The scanning probe microscope of claim 2 or 3,

the control device performs the following processing:

obtaining measurement data of the sample by relatively reciprocating the probe in a first direction and a second direction in the same measurement path of the sample, the first direction and the second direction being orthogonal to a height direction of the sample, the second direction being a direction opposite to the first direction,

storing first measurement data acquired by movement of the probe in the first direction in the same measurement path and second measurement data acquired by movement of the probe in the second direction in the same measurement path,

when the physical quantity is not fixed, a cause for which the physical quantity is not fixed is identified based on the stored first measurement data and second measurement data, and cause information enabling identification of the identified cause is stored.

6. The scanning probe microscope of claim 5,

the control device executes, as the second control, control of setting a measurement range of the sample to a measurement range excluding a portion where the physical quantity is not fixed, when a degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is equal to or greater than a threshold value.

7. The scanning probe microscope of claim 6,

the measurement range is set to a range adjacent to the portion.

8. The scanning probe microscope of claim 5,

the control device executes, as the second control, a process of stopping measurement of the sample for a predetermined standby time when a degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is smaller than a threshold value.

9. The scanning probe microscope of claim 5,

when the degree of coincidence between the first measurement data and data obtained by inverting the time series of the second measurement data is less than a threshold value, the control device performs, as the second control, the following processing:

calculating a first measurement difference value based on the first measurement data and the second measurement data on a first measurement path of the sample,

calculating a second measurement difference value based on the first measurement data and the second measurement data on a second measurement path of the sample,

acquiring an elapsed time from the end of the relative reciprocating movement of the probe in the first measurement path to the end of the relative reciprocating movement of the probe in the second measurement path,

calculating a standby time based on the first measured differential value, the second measured differential value, and the elapsed time,

stopping the measurement of the sample throughout the calculated standby time.

10. The scanning probe microscope of claim 5,

the control device stops the measurement of the sample when the first measurement data and the second measurement data are not stored.

11. The scanning probe microscope of claim 5,

the control means performs notification based on the reason information.

12. The scanning probe microscope of claim 2 or 3,

the control device can switch the following modes according to the input of a user:

a first mode in which measurement of the sample is resumed after the measurement of the sample is stopped; and

and a second mode in which the measurement of the sample is not resumed after the measurement of the sample is stopped.

13. A method for controlling a scanning probe microscope for measuring a sample, the scanning probe microscope comprising:

a sample stage for placing the sample;

a probe disposed so as to face the sample; and

a first drive mechanism that relatively moves the probe along a surface of the sample,

the control method comprises the following steps:

executing a first control for fixing a physical quantity acting between the probe and the sample; and

the measurement of the sample is stopped when the physical quantity is not fixed despite the execution of the first control.

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