Scanning probe microscope and control method

Abstract

To reduce acquisition of inaccurate measurement results even when a physical quantity acting between a probe and a sample is not constant.SOLUTION: An SPM 100 measures a sample S. The SPM 100 includes: a sample table 14 on which the sample S is placed; a probe 3 arranged opposite to the sample S; a fine movement mechanism 12 that relatively moves the probe 3 along a surface of the sample S so that interatomic force acting between the probe 3 and the sample S becomes constant by performing feedback control; and an information processing device 20 for stopping measurement of the sample S when the interatomic force is not constant even though the feedback control is performed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Conventionally, scanning probe microscopes (SPMs) equipped with a probe that moves relatively along the surface of a sample have been proposed. For example, the SPM described in JP 2021-004859 A (Patent Document 1) includes a control device, a sample stage on which a sample is placed, and a probe that moves relatively along the surface of the sample. The SPM measures the sample by driving the sample stage in the X-, Y-, and Z-axis directions. The control device also performs feedback control to keep the physical quantity (e.g., atomic force) acting between the probe and the sample constant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-004859 Summary of the Invention [Problem to be solved by the invention]

[0004] During the measurement of a sample using the SPM described above, even if the feedback control described above is executed, there are cases where the physical quantity acting between the probe and the sample does not remain constant. For example, this occurs when the sample has a convex portion that is too large for the SPM to measure. Continuing the measurement with the convex portion on the sample can result in inaccurate measurement results.

[0005] The present invention has been made to solve such problems, and aims to provide a technique that reduces the occurrence of inaccurate measurement results even when the physical quantity acting between the probe and the sample is not constant. [Means for solving the problem]

[0006] A scanning probe microscope according to the present disclosure measures a sample and includes a sample stage on which the sample is placed, a probe positioned opposite the sample, a first drive mechanism that moves the probe relatively along the surface of the sample by performing a first control so that a physical quantity acting between the probe and the sample remains constant, and a control device that stops measurement of the sample if the physical quantity does not remain constant despite the first control being performed.

[0007] The control method disclosed herein is a method for controlling a scanning probe microscope. The scanning probe microscope includes a sample stage on which a sample is placed, a probe placed facing the sample, and a first drive mechanism that moves the probe relatively along the surface of the sample. The control method includes performing a first control that keeps a physical quantity acting between the probe and the sample constant, and stopping measurement of the sample if the physical quantity does not become constant despite the execution of the first control. [Effects of the Invention]

[0008] According to the present disclosure, even if control is performed to keep the physical quantity acting between the probe and the sample constant, if the physical quantity does not become constant, the measurement of the sample is stopped, and therefore, according to the present disclosure, it is possible to reduce the occurrence of inaccurate measurement results. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of an SPM according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of an information processing device. [Figure 3] FIG. 10 is a diagram illustrating an example of a measurement range. [Figure 4] FIG. 2 is a functional block diagram of the information processing device. [Figure 5] FIG. 10 is a diagram illustrating a method for detecting the occurrence of thermal drift. [Figure 6] FIG. 10 is a diagram showing a second control when an excessively large uneven portion is present on the sample. [Figure 7] 1 is a flowchart illustrating an operation method of the SPM. [Figure 8] 10 is a flowchart for explaining an operation method of the SPM according to the third embodiment. [Figure 9] 10 shows an example of a notification message displayed on the display device. [Figure 10] 10 shows an example of a notification message displayed in a display area of ​​a display device. [Figure 11] 10 is an example of a mode selection screen. [Figure 12] FIG. 10 is a diagram illustrating a method for predicting a waiting time. [Figure 13] FIG. 10 is a diagram for explaining thermal drift. [Figure 14] 10 is a flowchart illustrating a method of operating an SPM according to a modified example. [Figure 15] 10 is a flowchart of a waiting time calculation process. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0011] [First embodiment] FIG. 1 is a diagram illustrating a schematic configuration of a scanning probe microscope (SPM) according to an embodiment. A scanning probe microscope 100 according to this embodiment is typically an atomic force microscope (AFM) that measures the shape of the surface of a sample S by utilizing a physical quantity acting between a probe (tip) 3 and the surface of the sample S. The present disclosure can also be similarly applied to other scanning probe microscopes, such as a scanning tunneling microscope (STM). The physical quantity is, for example, an atomic force (attractive or repulsive force). In the following, the height direction of the sample S is defined as the Z-axis direction, and directions perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction.

[0012] 1, a scanning probe microscope 100 includes, as its main components, a measuring device 10, an information processing device 20, a display device 30, and an input device 40. The measuring device 10 includes, as its 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 drive unit 16, a Z-direction drive unit 18, and a feedback signal generator 22. The "fine movement mechanism 12" in this embodiment corresponds to the "first drive mechanism" in this disclosure, and the "coarse movement mechanism 13" in this embodiment corresponds to the "second drive mechanism" in this disclosure.

[0013] The sample S is placed on the sample stage 14. 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. The fine movement 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 sample stage 14 in the Z-axis direction. The XY scanner 12xy has a piezoelectric element that deforms in response to a voltage applied from the XY-direction driver 16. The Z scanner 12z has a piezoelectric element that expands and contracts in response to a voltage applied from the Z-direction driver 18. The Z scanner 12z expands and contracts due to this piezoelectric element. Note that the XY scanner 12xy and the Z scanner 12z are not limited to having a piezoelectric element.

[0014] In this embodiment, when the voltage applied by the Z-direction driver 18 is at its maximum value Vmax, the sample stage 14 is driven to the highest position in the Z-axis direction. Furthermore, when the voltage applied by the Z-direction driver 18 is at its 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. Furthermore, when the voltage applied by the Z-direction driver 18 is 0, the sample stage 14 is driven to its initial position. In this embodiment, the initial position is the center position in the Z-axis direction. Alternatively, as a modified example, the sample stage 14 may be driven to the lowest position in the Z-axis direction when the voltage applied by the Z-direction driver 18 is at its maximum value Vmax, and to the highest position in the Z-axis direction when the voltage is at its minimum value Vmin.

[0015] The cantilever 2 is formed in the shape of a leaf spring, one end of which is supported by a holder 4. The other end of the cantilever 2 is a free end, which is positioned so as to face the sample S. In the example shown in FIG. 1, it is positioned upward in the Z-axis direction. The cantilever 2 has a front surface which faces the sample S and a back surface opposite the front surface. A probe 3 is positioned on the 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 is configured to reflect light. The tip of the cantilever 2 is displaced in the Z-axis direction due to a physical quantity (e.g., atomic force) acting between the probe 3 and the sample S.

[0016] 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 (i.e., the amount of displacement of the tip). When measuring a sample S, the optical system 1 irradiates a laser beam onto the back surface (reflecting surface) of the cantilever 2 and detects the laser beam reflected by the reflecting surface. Specifically, the optical system 1 has a laser light source 6, a beam splitter 5, a reflecting mirror 7, and a photodetector 8.

[0017] 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. The laser light LA ​​emitted from the laser light source 6 is reflected by the beam splitter 5 and irradiated onto the back surface (reflecting surface) of the cantilever 2. The laser light reflected by the back surface of the cantilever 2 is further reflected by the reflecting mirror 7 and enters the photodetector 8.

[0018] Photodetector 8 has a light-receiving surface that is divided into multiple (for example, two) parts in the Z-axis direction (displacement direction) of cantilever 2. Alternatively, photodetector 8 has a light-receiving surface that is divided into four parts in the Z-axis and Y-axis directions. When the tip of cantilever 2 is displaced in the Z-axis direction, the ratio of the amount of light irradiated onto the multiple light-receiving surfaces changes, and therefore the amount of deflection (amount of displacement) of cantilever 2 can be detected based on the multiple amounts of light received.

[0019] The feedback signal generating unit 22 calculates the amount of deflection of the cantilever 2 by arithmetic processing of the detection signal provided by 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. This control is hereinafter referred to as "feedback control." Feedback control corresponds to the "first control" of the present disclosure. Specifically, the feedback signal generating unit 22 calculates the deviation Sd between the calculated amount of deflection of the cantilever 2 and a target value, and calculates a control amount for driving the Z scanner 12z so that the deviation Sd becomes zero. The feedback signal generating unit 22 calculates a voltage value Vz for displacing the Z scanner 12z corresponding to this 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 unit 18 applies the voltage value Vz to the Z scanner 12z. In this way, Z direction drive unit 18 receives input of a voltage value from feedback signal generation unit 22, and applies a voltage based on that voltage value to Z scanner 12z.

[0020] 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 to the XY-direction driving unit 16 so that the sample stage 14 moves in the X-axis and Y-axis directions relative to the probe 3 in accordance with preset scanning conditions, and outputs the calculated voltage values ​​to the XY-direction driving unit 16. The XY-direction driving unit 16 applies the voltage values ​​Vx and Vy to the XY scanner 12xy.

[0021] The coarse movement mechanism 13 moves the sample stage 14 in the X-axis direction, the Y-axis direction, and the Z-axis direction. Furthermore, the first movement range of the sample stage 14 by the fine movement mechanism 12 in the X-axis direction, the Y-axis direction, and the Z-axis direction is configured to be smaller than the second movement range of the sample stage 14 by the coarse movement mechanism 13. Furthermore, there are cases where the SPM 100 is unable to measure the sample S appropriately due to reasons described below. In such cases, the coarse movement mechanism 13 executes a retraction process under the control of the information processing device 20. The retraction 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.

[0022] The information processing device 20 mainly controls the operation of the measuring device 10. Measurement data indicating the feedback amount in the Z-axis direction (the applied voltage Vz and deviation Sd to the Z scanner 12z) is sent from the Z-axis driver 18 to the information processing device 20. The measurement data is transmitted for each measurement point determined at predetermined intervals in the Y-axis direction of the sample S (see FIG. 3). The information processing device 20 stores the 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 indicating the relationship between the pre-stored voltage Vz and the corresponding displacement amount of the sample S (sample stage 14) in the Z-axis direction. The calculated displacement amount reflects a value indicating the position of the sample S in the Z-axis direction (hereinafter also referred to as the "Z value"). The information processing device 20 calculates the displacement amount of the sample S in the Z-axis direction at each position in the X-axis and Y-axis directions within the scanning range, thereby creating two-dimensional or three-dimensional measurement data representing the surface shape of the sample S. The information processing device 20 displays information such as the surface shape of the sample S on the display device 30 based on the measurement data.

[0023] The image 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. The Z value corresponds to the surface height at each position on the sample stage 14, and at the position where the sample S is present, the Z value 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, various information is input from the user via the input device 40.

[0024] [Hardware configuration of information processing device] 2 is a diagram showing an example of the hardware configuration of the information processing device 20. Referring to FIG. 2, the information processing device 20 has, as its main components, 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 / F 170, and an input I / F 172. The components are 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 measuring device 10. Alternatively, the information processing device 20 may be configured as a separate entity from the scanning probe microscope 100 and configured to communicate bidirectionally with the scanning probe microscope 100.

[0025] The communication I / F 168 is an interface for communicating with the measurement device 10. The display I / F 170 is an interface for communicating with the display device 30. The input I / F 172 is an interface for communicating with the input device 40.

[0026] ROM 162 stores programs executed by CPU 160. RAM 164 can temporarily store data generated by the execution of programs in CPU 160 and data input via communication I / F 168. RAM 164 can function as a temporary data memory used as a work area. HDD 166 is a non-volatile storage device. A semiconductor storage device such as a flash memory may be used instead of HDD 166.

[0027] The program stored in ROM 162 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 so-called product program that can be downloaded via the Internet or the like. The information processing device 20 reads the program provided from a storage medium or the Internet or the like. The information processing device 20 stores the read program in a predetermined storage area (for example, ROM 162). By executing the program, the CPU 160 can perform the image data acquisition process described below.

[0028] The display device 30 can display a setting screen for setting image data acquisition conditions. Furthermore, while the image data is being acquired, the display device 30 can display the image data created by the information processing device 20 and the data obtained by processing this image data.

[0029] The input device 40 accepts inputs from a user (e.g., an analyst) including instructions for the information processing device 20. The input device 40 includes a keyboard, a mouse, and a touch panel that is integrated with the display screen of the display device 30, and accepts image acquisition conditions and the like.

[0030] [Measurement range of sample S] The user can input a 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 to a rectangular shape. As shown in FIG. 3, the information processing device 20 relatively moves the probe 3 back and forth along a measurement path L (first line path) in the Y-axis direction of the sample S. In the example of FIG. 3, the positive direction of the Y-axis corresponds to the "first direction" in this disclosure, and the negative direction of the Y-axis corresponds to the "second direction" in this disclosure. When the reciprocating movement of the probe 3 in the measurement path L is completed, the probe 3 is relatively moved a predetermined amount in the X-axis direction. Then, the probe 3 moves relatively again back and forth in the next measurement path (second line path). In this way, the probe 3 moves back and forth in all lines in the measurement range R1. As a modified example, the probe 3 may move back and forth in the X-axis direction.

[0031] [Processing of information processing device] FIG. 4 is a functional block diagram of information processing device 20. Information processing device 20 has input unit 102, processing unit 104, driving unit 106, and memory unit 108. Measurement data (applied voltage Vz and deviation Sd) from Z-direction driving unit 18 is input to input unit 102. This measurement data is output to processing unit 104. Processing unit 104 generates measurement data by calculating the displacement of sample S in the Z-axis direction. Here, data generated by processing unit 104 when probe 3 is relatively moved in the first direction is referred to as "first measurement data." The first measurement data is measurement data on the outward movement. Furthermore, data generated by processing unit 104 when probe 3 is relatively moved in the second direction is referred to as "second measurement data." The second measurement data is measurement data on the return movement. In this way, processing unit 104 generates the first measurement data and the second measurement data.

[0032] Furthermore, the processing unit 104 determines whether the deviation Sd is zero. When the measurement of the sample S is normal, the deviation Sd becomes zero as a result of the above-mentioned feedback control being executed. However, there are cases where the deviation Sd does not become zero due to the following causes. The causes include a first cause and a second cause.

[0033] The first cause is the presence of excessively uneven portions in the sample S, which will be described later. Excessively uneven portions refer to excessively high convex portions and excessively deep concave portions. Excessively high convex portions are convex portions having a height greater than the first movement range in the Z-axis direction (the movement range of the sample stage 14 by the fine movement mechanism 12). Moreover, excessively deep concave portions are concave portions having a depth greater than the first movement range in the Z-axis direction. Here, the first movement range of the sample stage 14 by the fine movement mechanism 12 is several μm to several tens of μm.

[0034] The second cause is thermal drift, which occurs when heat is generated from the SPM 100 or the sample S while the SPM 100 is measuring the sample S. Thermal drift throughout the SPM 100 may cause an unintended change in the relative position between the probe 3 and the sample S.

[0035] Unintended changes in the relative position between the probe 3 and the sample S can occur in two ways: the probe 3 moving closer to the sample S over time, or the probe 3 moving away from the sample S over time. For example, if thermal drift occurs in the direction in which the probe 3 moves closer to the sample S, continuing measurement of the sample S can result in a phenomenon in which the deviation Sd does not become zero even when the Z scanner 12z is fully retracted. Conversely, if thermal drift occurs in the direction in which the probe 3 moves away from the sample S, the deviation Sd cannot become zero even when the Z scanner 12z is fully extended. In other words, because the voltage applied to the Z scanner 12z by the Z-direction driver 18 due to the thermal drift is at its maximum value Vmax or its minimum value Vmin, the deviation Sd does not become zero (the atomic force does not become constant) even when the feedback control described above is executed. This state is referred to as a state in which the influence of thermal drift beyond the operating range of the fine movement mechanism 12 occurs.

[0036] Hereinafter, "thermal drift that acts to bring the probe 3 and the sample S closer together over time" will also be referred to as "first thermal drift." Also, "thermal drift that acts to move the probe 3 and the sample S away from each other over time" will also be referred to as "second thermal drift." Also, when thermal drift occurs, it is assumed that the type of thermal drift does not change midway. For example, when a first thermal drift occurs, it is assumed that there is no case where a second thermal drift occurs midway. Also, when a second thermal drift occurs, it is assumed that there is no case where a first thermal drift occurs midway.

[0037] Next, a method for identifying the type of cause (whether it is the first cause or the second cause) will be described. When the processing unit 104 determines that the deviation Sd is not zero, it acquires measurement data (previously acquired measurement data) stored in the storage unit 108. For example, the processing unit 104 acquires N pieces of measurement data that were most recently stored (most recently acquired), where N is an integer equal to or greater than 1. Each of the N pieces of measurement data includes first measurement data and second measurement data. Then, the processing unit 104 identifies the type of cause based on the measurement data.

[0038] FIG. 5 shows an example of past measurement data. In FIGS. 5A to 5C, the horizontal axis represents time t, and the vertical axis represents the height of the sample S measured by the SPM 10. FIG. 5 also shows measurement data from the outbound journey and measurement data from the return journey. The start time of the measurement on the outbound journey is designated "t0," the time of reversal from the outbound journey to the return journey is designated "t1," and the end time of the measurement on the return journey is designated "t2." Note that in the example of FIG. 5, for convenience, when reversing from the outbound journey to the return journey, the end time of the measurement on the outbound journey is set to the same as the start time of the measurement on the return journey; however, the end time of the measurement may differ from the start time of the measurement on the return journey.

[0039] The processing unit 104 converts the measurement data on the return path into inverse data (third measurement data) in which the time series of the measurement data on the return path is reversed. Then, the processing unit 104 calculates the degree of agreement between the measurement data on the forward path (first measurement data) corresponding to the return path and the inverse data. The degree of agreement is a value indicating the degree of agreement between the measurement data on the forward path and the inverse data. The degree of agreement is calculated, for example, based on the average value or standard deviation of the differences between the values ​​indicated by the measurement data on the forward path and the inverse data measured at multiple identical positions on the sample S.

[0040] 5A is a diagram for explaining the cause of the absence of thermal drift and the presence of excessively large unevenness (i.e., the first cause). As shown in FIG. 5A, the measurement data during the measurement period on the forward path and the reverse data match (the degree of match is equal to or greater than a threshold). Therefore, when the deviation Sd is not zero and the past measurement data shown in FIG. 5A is acquired, the processing unit 104 identifies the first cause.

[0041] Fig. 5(B) shows a case where a thermal drift (first thermal drift) occurs that causes the probe 3 and the sample S to approach each other. In Fig. 5(B), the measurement data on the return path indicates that the probe 3 and the sample S approach each other due to the influence of the first thermal drift.

[0042] Figure 5(C) shows a case where a thermal drift (second thermal drift) occurs that acts to move the probe 3 away from the sample S. In Figure 5(C), the measurement data on the return path indicates that the probe 3 and the sample S move away from each other due to the influence of the second thermal drift. Note that the waveforms (normal waveforms) when no thermal drift occurs on the return paths in Figures 5(B) and 5(C) are shown by dashed lines.

[0043] Note that the measurement data in Fig. 5 is an example. For example, depending on the configuration of the SPM 100, 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.

[0044] As shown in Figures 5(B) and 5(C), the measurement data during the measurement period on the forward path and the reverse data do not match (the degree of match is less than a threshold). Therefore, when the deviation Sd is not zero and the past measurement data shown in Figure 5(B) is acquired, the processing unit 104 identifies the second cause (the occurrence of a first thermal drift). Also, when the deviation Sd is not zero and the past measurement data shown in Figure 5(C) is acquired, the processing unit 104 identifies the second cause (the occurrence of a second thermal drift).

[0045] Furthermore, when the processing unit 104 identifies the type of cause, it stores a flag (cause information) capable of identifying the type of cause in the storage unit 108. When the processing unit 104 identifies the first cause, it stores an unevenness flag in the storage unit 108. This unevenness flag is a flag indicating that an excessively large unevenness has been detected. When the processing unit 104 identifies the second cause, it stores a thermal drift flag in the storage unit 108. The thermal drift flag is a flag indicating that a thermal drift has been detected. Furthermore, when the processing unit 104 identifies the first or second cause, it transmits a cause signal indicating the identified cause to the measuring device 10. By receiving this cause signal, the measuring device 10 can identify the cause that has occurred.

[0046] Furthermore, if the sample S has excessively large unevenness, which is the first cause, not only will the SPM 100 be unable to measure the sample S appropriately, but continuing the measurement may cause the sample S and the probe 3 to come into contact, damaging at least one of the sample S and the probe 3. Therefore, the SPM 100 of this embodiment executes a second control to eliminate the influence of the first cause, and continues the measurement after the second control.

[0047] FIG. 6 illustrates a second control for eliminating the influence of the first cause. FIG. 6 shows the sample S and the measurement range R1 set by the user. Assume that the deviation Sd does not become zero (a special convex portion exists) in the portion α as shown in FIG. 6(A). In this case, the driver 106 drives the coarse adjustment mechanism 13 to perform a retraction process (a process for increasing the distance between the probe 3 and the sample stage 14 (sample S)). This allows the SPM 100 to prevent a collision between the probe 3 and the sample S. Then, the measuring device 10 sets the voltage applied to the Z scanner 12z by the Z-direction driver 18 to zero. This is because the Z scanner 12z is likely to be fully retracted or fully extended in order to follow the shape of the excessively large concave-convex portion. Furthermore, the processor 104 changes the measurement range from the measurement range R1 to a new measurement range R2, as shown in FIG. 6(B). The driving unit 106 drives the coarse movement mechanism 13 to move the new measurement range R2 so that it can be measured. Measuring device 10 Then, measurement of sample S resumes in measurement range R2. Because the voltage applied to the Z scanner from Z-direction driver 18 is set to 0, sample stage 14 is driven to its initial position. Therefore, SPM 100 can reduce collisions between probe 3 and sample stage 14, and can measure measurement range R2 with ample room in the extension and contraction range of Z scanner 12z.

[0048] Here, measurement range R2 is a range excluding portion α, i.e., a measurement range excluding portion α where the atomic force was not constant, and is desirably set to have the same area as measurement range R1. More specifically, measurement range R2 is a range adjacent to portion α. ​​"Adjacent to portion α" may mean "portion α exists on the frame that forms measurement range R2." "Adjacent to portion α" may also mean "a predetermined distance away from the frame that forms measurement range R2." Furthermore, information processing device 20 stores the XY coordinates of portion α where the first cause occurred. Then, information processing device 20 sets a new measurement range R2 based on the XY coordinates of portion α.

[0049] Furthermore, if the first cause occurs again in the new measurement range R2, a new measurement range is set that excludes the portion α where the first cause occurred again. In this way, the SPM 100 repeats resetting the measurement range until measurement in that measurement range is completed without the first cause occurring. Furthermore, if a measurement range in which the first cause does not occur cannot be set for the sample S despite having reset the measurement range multiple times, the SPM 100 determines that measurement of the sample S is impossible and terminates the measurement process. Therefore, the information processing device 20 executes a notification indicating that measurement is impossible.

[0050] Furthermore, if thermal drift, which is the second cause, occurs, the SPM 100 cannot properly measure the sample S. Therefore, the SPM 100 of this embodiment executes a second control to reduce the influence of the second cause, and continues measurement after the second control.

[0051] Suppose that the deviation Sd does not become zero during the measurement of the sample S (the effect of thermal drift exceeding the operating range of the fine adjustment mechanism 12 occurs). In this case, the driving unit 106 must execute a retraction process (a process to increase the distance between the probe 3 and the sample stage 14 (sample S)) by driving the coarse adjustment mechanism 13. The second control for eliminating the first and second causes includes this retraction process. This makes it possible to prevent a collision between the probe 3 and the sample S. Then, the measuring device 10 controls the Z scanner 12z to application As described above, in the "state where the influence of thermal drift exceeding the operating range of the fine movement mechanism 12 occurs," the voltage applied by the Z direction drive unit 18 to the Z scanner 12z is at the maximum value Vmax or the minimum value Vmin, so the voltage is adjusted to 0. The second control to eliminate the first and second causes is as follows: application This includes a process of setting the voltage to 0. Furthermore, the driver 106 drives the coarse adjustment mechanism 13 to bring the probe 3 and the sample S closer together again, and resumes measurement of the sample S in the measurement range R1. Because the voltage applied to the Z scanner from the Z-direction driver 18 has been set to 0, the Z scanner 12z can extend and retract again.

[0052] [How SPM works] Fig. 7 is a flowchart for explaining the operation method of the SPM 100. The process of Fig. 7 is executed for each measurement point in the set measurement range.

[0053] In step S2, the SPM 100 acquires the deviation Sd. Next, in step S4, the SPM 100 drives the Z scanner 12z by executing feedback control so that Sd = 0. Next, in step S5, the SPM 100 determines whether Sd = 0. If Sd = 0, the SPM 100 stores the measurement data obtained when Sd = 0 was determined in step S21 in the memory unit 108. Next, in step S22, the SPM 100 determines whether the measurement of the sample S has been completed. If the determination in S22 is YES, the process ends. On the other hand, if the determination in step S22 is NO, the process returns to step S2.

[0054] If step S5 returns NO, then in step S6, the SPM 100 temporarily stops the measurement. Next, in step S7, the SPM 100 drives the coarse adjustment mechanism 13 to move the sample stage 14 away from the cantilever 2. Then, in S8, the SPM 100 sets the voltage applied from the Z direction driver 18 to the Z scanner 12 to 0. Furthermore, in step S9, the SPM 100 identifies the reason why Sd did not become 0.

[0055] FIG. 8 is a diagram for explaining the cause identification process of step S9. In step S72, the SPM 100 determines whether measurement data is stored in the storage unit 108. Here, the measurement data is the measurement data for the sample S for which the process of FIG. 7 was started. If there is no measurement data (for example, if the measurement of the first line has not been completed), the SPM 100 cannot identify the cause. Therefore, if there is no measurement data stored in the storage unit 108 in step S72 (NO in step S72), the SPM 100 stops the measurement in step S82 and then terminates the process. The SPM 100 may also notify the user that the process has ended.

[0056] On the other hand, if the determination in step S72 is YES, the process proceeds to step S74. In step S74, the SPM 100 generates the reverse data described above. Next, in step S76, it is determined whether the degree of match between the forward path data and the generated reverse data is equal to or greater than a threshold (see the description of FIG. 5).

[0057] If the determination in step S76 is YES (i.e., the case is FIG. 5(A)), the SPM 100 detects an excessively large uneven portion (identifies the first cause) in step S78. On the other hand, if the determination in step S76 is NO (i.e., the case is FIG. 5(B) or FIG. 5(C)), the SPM 100 detects a thermal drift (identifies the second cause) in step S80.

[0058] 7. After completing the process of step S9, the SPM 100 determines the identified cause in step S10. If the cause is excessively large unevenness, the process proceeds to step S11, and if the cause is thermal drift, the process proceeds to step S16.

[0059] In step S11, the SPM 100 stores the uneven portion flag in a predetermined storage area (for example, the RAM 164 shown in FIG. 2). Next, in step S12, the SPM 100 sets a new measurement range R2 (see FIG. 6) that excludes the excessively uneven portion (i.e., the portion determined in step S5 that the deviation Sd is not 0). Next, in step S14, the SPM 100 resumes measurement of the sample S in the new measurement range R2, and the process returns to step S2.

[0060] In addition, in step S16, the SPM 100 stores the thermal drift flag. Next, in step S20, the SPM 100 again drives the coarse adjustment mechanism 13 to bring the probe 3 and the sample stage 14 (sample S) closer to each other, resumes measurement of the sample S in the measurement range R1, and the process returns to step S2.

[0061] During sample measurement using a conventional SPM, there are cases where the atomic force does not remain constant even when the above-mentioned feedback control is performed. For example, this occurs when the sample has a convex portion that is too large for the SPM to measure. Continuing measurement with the convex portion on the sample can result in inaccurate measurement results.

[0062] Therefore, if Sd=0 is not satisfied (if NO is determined in step S5), the SPM 100 stops the measurement in step S6. Therefore, the SPM 100 can reduce the possibility of obtaining inaccurate measurement results.

[0063] Furthermore, if the SPM remains stopped while measuring the sample, a problem may arise in that the time required to complete the measurement of the sample is delayed.

[0064] Furthermore, for example, the SPM 100 may execute a measurement that takes a long time. Examples of measurements that take a long time include measurements with a high pixel count, measurements at a slow scanning speed, and measurements of multiple samples. In such long-time measurements, the user may be located far away from the SPM 100. In this case, if the user unintentionally stops the sample measurement, a long time may pass without the user noticing that the measurement has stopped. Furthermore, the user will need to restart the measurement, which places a burden on the user.

[0065] On the other hand, if the atomic force does not become constant, the SPM 100 stops the measurement of the sample S, then executes the second control, and after executing the second control, resumes the measurement of the sample (see steps S14 and S20 in FIG. 7). The second control is a control for reducing the influence of the cause that occurred. In the present embodiment, this second control is, for example, steps S7 and S8. The SPM 100 then resumes the measurement of the sample S after executing the second control (steps S14 and S20). Therefore, the SPM 100 can resume the measurement of the sample S after eliminating the cause that prevents Sd from becoming 0. This allows the user to reduce delays in the measurement of the sample. Furthermore, the user does not need to operate the SPM 100 to measure the sample S again, thereby reducing the burden on the user.

[0066] The second control also includes a process (step S7) for retracting the sample stage 14. Therefore, it is possible to reduce the chance of the probe 3 and the sample stage 14 colliding with each other.

[0067] The second control is to the Z scanner 12z. application This includes a process of setting the voltage to 0. Therefore, the sample stage 14 is driven to its initial position. Therefore, the SPM 100 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 extension and contraction range of the Z scanner 12z.

[0068] In addition, the SPM 100 identifies the cause based on the past first measurement data and second measurement data ( Figure 8 Therefore, the SPM100 can identify the cause of the non-constant atomic force.

[0069] Furthermore, if the degree of match between the forward path data and the reverse path data is higher than a threshold, the SPM 100 stores a concave-convex portion flag and executes the control of step S12 as the second control. The control of step S12 is a control for setting the measurement range of the sample S to a measurement range excluding the portion where the atomic force was not constant. Therefore, by setting the measurement range R1 of the sample S to a measurement range R2 excluding the portion α, the SPM 100 can measure the sample S in places other than the special convex portion.

[0070] 6, the newly set measurement range R2 is adjacent to the area α where the special convex portion exists (the area where the deviation Sd does not become zero even when feedback control is executed). Therefore, the amount of movement on the XY plane when changing the measurement range can be minimized.

[0071] Furthermore, if the first measurement data and the second measurement data have not been acquired (NO in step S72 in FIG. 8), the SPM 100 stops measuring the sample (step S82), thereby preventing the measurement of the sample S from being continued in a state where the cause of Sd not being zero cannot be identified.

[0072] [Other embodiments] (1) The information processing device 20 may be configured to issue a notification based on the identified cause (the type of stored flag). For example, when the first cause is identified (when the measurement range R1 is set to the measurement range R2), the display device 30 may notify the user. FIG. 9 shows an example of a notification message displayed in the display area 30A of the display device 30. In the example of FIG. 9, a notification message 140 is displayed stating, "The measurement range has been changed because an unmeasurable convex or concave portion was found." This notification is issued at a predetermined timing after the occurrence of the first cause. This predetermined timing is, for example, the timing when measurement of the sample S in the measurement range R2 is completed. This allows the SPM 100 to notify the user that an unmeasurable convex or concave portion was found within the measurement range and that the measurement range has been changed.

[0073] Furthermore, the information processing device 20 may notify the user via the display device 30 when the second cause occurs. Fig. 10 shows an example of a notification message displayed in the display area 30A of the display device 30. The notification message 150 in Fig. 10 reads, "Thermal drift has occurred." By providing such a notification, the SPM 100 can make the user aware that thermal drift has occurred.

[0074] (2) In FIG. 6, a configuration has been described in which the SPM 100 automatically changes the measurement range when a special convex portion or special concave portion of the sample S is detected. However, there are cases in which the user does not want to change the measurement range in this way. In consideration of this, the SPM 100 may be configured to allow the user to select between an automatic measurement mode and a stop mode. The automatic measurement mode is a mode in which measurement of the sample S is stopped and then resumed. The stop mode is a mode in which measurement of the sample S is not resumed after 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.

[0075] 11 shows an example of a mode selection screen. This selection screen is displayed in the display area 30A of the display device 30. This selection screen includes a statement 190 saying "Please select a mode," an automatic measurement mode option 192, and a stop mode option 194.

[0076] The user can set the mode by checking the checkbox of the desired option. For example, the user uses the input device 40 to check the checkbox. The SPM 100 accepts the user's input of the mode selection and sets the selected mode. In this way, the user can select either the stop mode or the automatic measurement mode, thereby improving user convenience.

[0077] (3) In FIG. 7, if thermal drift occurs, the Z scanner 12z is application In the above description, the voltage is reset to 0, and then measurement is immediately resumed in step S20. However, if measurement is resumed immediately, the effects of thermal drift in the entire SPM 100 may remain, and the effects of thermal drift that exceeds the operating range of the fine adjustment mechanism 12 may again cause an unintended change in the relative position between the probe 3 and the sample S.

[0078] Therefore, a waiting time may be provided to reduce or eliminate the thermal drift of the entire SPM 100 before resuming the measurement of the sample S. In this way, the second control when thermal drift occurs includes a process of stopping the measurement of the sample S for the waiting time.

[0079] In this modified example, a method for calculating this standby time will be described. Generally, when thermal drift occurs, the amount of thermal drift (the degree of influence of thermal drift) decreases as time passes from the time of the occurrence (see graph A in FIG. 12). The SPM 100 of this modified example calculates (or estimates) the standby time based on this phenomenon.

[0080] Fig. 12 is a diagram for explaining a method for predicting standby time. As shown in Fig. 12, the amount of thermal drift M1 at timing t11, the amount of thermal drift M2 at timing t12, plot A1, and plot A2 are shown. Furthermore, graph A of a function showing the relationship between standby time and thermal drift is shown.

[0081] The information processing device 20 creates a function graph A based on the thermal drift amount M1, the thermal drift amount M2, and the elapsed time T0. More specifically, the information processing device 20 calculates the difference ΔM between the thermal drift amount M1 and the thermal drift amount M2. The information processing device 20 then calculates the rate of change of the thermal drift amount by dividing the difference ΔM by the elapsed time T0. The information processing device 20 then creates the function graph A based on the rate of change. The formula for creating the function is stored in, for example, the storage unit 108.

[0082] Then, the information processing device 20 calculates, as the waiting time, a time T1 until the amount of thermal drift reaches the minimum value M0 (timing t13) based on graph A. The start timing of the waiting time T1 is, for example, the timing when the calculation of the waiting time T1 is completed.

[0083] FIG. 13 is a diagram for explaining the thermal drift amount M1 and the thermal drift amount M2. The information processing device 20 uses past measurement data from two or more measurement paths (two or more lines). As shown in FIG. 13(A), the information processing device 20 calculates a first measurement difference value M1a based on the first measurement data (measurement data from the forward path) and the second measurement data (measurement data from the backward path) in the first measurement path of the sample S (the first line in the example of FIG. 13). Specifically, the information processing device 20 calculates reverse data from the forward path (data whose time series is reversed). In FIG. 13(A), the reverse data from the forward path is indicated by a dashed line. Then, the information processing device 20 calculates a first measurement difference value M1a, which is the difference between the reverse data and the backward path data. The first measurement difference value M1a is a value corresponding to the thermal drift amount. The larger the thermal drift amount, the larger the measurement difference value. Furthermore, the information processing device 20 calculates the amount of thermal drift M1 by multiplying the first measurement difference value M1a by a predetermined coefficient C. The coefficient C is a real number, and may be set to 1.

[0084] 13(B), the information processing device 20 calculates a second measurement difference value M2a based on the first measurement data (measurement data on the outward path) and the second measurement data (measurement data on the return path) for a second measurement path of the sample S (the second line in the example of FIG. 13). Specifically, the information processing device 20 calculates reverse data for the outward path (data whose time series is reversed). In FIG. 13(B), the reverse data for the outward path is indicated by a dashed line. Then, the information processing device 20 calculates a second measurement difference value M2a, which is the difference between the reverse data and the return path data. No. 2 The measurement difference value M2a is a value corresponding to the amount of thermal drift. Furthermore, as described above, when thermal drift occurs, the amount of thermal drift generally decreases with the passage of time from the time of the occurrence. Therefore, the second measurement difference value M2a is smaller than the first measurement difference value M1a. Furthermore, the information processing device 20: No. 2 Measurement difference value M2 The amount of thermal drift M2 is calculated by multiplying a by the coefficient C described above.

[0085] Furthermore, the information processing device 20 acquires the elapsed time T0 from when the relative reciprocating movement of the probe 3 in the first measurement path ends (timing t11 in FIG. 12) to when the relative reciprocating movement of the probe in the second measurement path ends (timing t12 in FIG. 12). The information processing device 20 can acquire the elapsed time T0 from the scanning speed of the probe 3, the number of pixels to be measured, etc. The information processing device 20 may also have a timer for measuring the elapsed time T0.

[0086] Then, the information processing device 20 creates graph A based on the thermal drift amount M1 (a value calculated from the first measurement difference value M1a), the thermal drift amount M2 (a value calculated from the second measurement difference value M2a), and the elapsed time T0, and uses the graph A to calculate the waiting time T1.

[0087] 14 is a flowchart for explaining the operation method of the SPM of this modified example. In the flowchart of Fig. 14, steps S17 and S18 are added between steps S16 and S20 of the flowchart of Fig. 7.

[0088] After the process of step S16 is completed, in step S17, the SPM 100 calculates a waiting time T1. Next, in step S18, the SPM 100 determines whether the waiting time T1 has elapsed. The SPM 100 executes a process of stopping the measurement of the sample S for the waiting time as the second control described above (NO in step S18). Then, when the waiting time T1 has elapsed (YES in step S18), the SPM 100 resumes the measurement of the sample S in step S20.

[0089] 15 is a flowchart of the waiting time calculation process in step S17. In step S102, the SPM 100 calculates a first measurement difference value M1a based on the first measurement data and second measurement data from the past first measurement path. Next, in step S104, the SPM 100 calculates a second measurement difference value M2a based on the first measurement data and second measurement data from the past second measurement path. 。

[0090] Next, in step S106, the SPM 100 acquires the elapsed time T0. Then, the SPM 100 calculates the waiting time T1 by creating a graph A. Note that in this modification, the waiting time T1 is calculated using data from two plots (plots A1 and A2) as shown in FIG. 12, but graph A may be calculated using data from three or more plots.

[0091] According to this modification, the SPM 100 can calculate the waiting time T1 according to the amount of thermal drift that is occurring. Furthermore, the SPM 100 resumes measurement of the sample S after the waiting time T1 has elapsed, and therefore can perform measurement of the sample S with reduced effects of thermal drift.

[0092] Furthermore, in this modification, the SPM 100 calculates the waiting time T1, but the waiting time T1 may be a predetermined time. The predetermined time is, for example, one hour. The waiting time T1 may also be set by the user. Even with this configuration, the SPM 100 resumes measurement of the sample S after the waiting time T1 has elapsed, and therefore, it is possible to perform measurement of the sample S with reduced effects of thermal drift.

[0093] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0094] (Item 1) A scanning probe microscope according to one embodiment measures a sample and includes a sample stage on which the sample is placed, a probe placed opposite the sample, a first drive mechanism that moves the probe relatively along the surface of the sample by performing a first control so that a physical quantity acting between the probe and the sample becomes constant, and a control device that stops measurement of the sample if the physical quantity does not become constant despite the first control being performed.

[0095] With this configuration, even if the physical quantity acting between the probe and the sample is not constant, the measurement of the sample is stopped, thereby reducing the possibility of obtaining inaccurate measurement results.

[0096] (Item 2) In the scanning probe microscope described in item 1, when the physical quantity does not become constant, the control device stops the measurement of the sample, then performs the second control, and after performing the second control, resumes the measurement of the sample.

[0097] With this configuration, even if the physical quantity acting between the probe and the sample does not become constant, it is possible to resume measurement of the sample.

[0098] (Item 3) The scanning probe microscope according to item 2 further comprises a second drive mechanism that executes a retraction process to increase the distance between the probe and the sample stage, and the second control includes the retraction process.

[0099] With this configuration, when the physical quantity acting between the probe and the sample is not constant, a retraction process is performed to increase the distance between the probe and the sample stage, thereby reducing collisions between the probe and the sample stage.

[0100] (Item 4) In the scanning probe microscope according to item 2 or 3, the first driving mechanism comprises: application The sample stage is driven in response to the applied voltage. application If the applied voltage is 0, the sample stage is driven to the initial position, and the second control is application This includes a process to set the applied voltage to zero.

[0101] With this configuration, when the physical quantity acting between the probe and the sample is not constant, the sample stage can be driven to the initial position, thereby reducing the chance of the probe and the sample stage colliding when the measurement of the sample is resumed.

[0102] (Item 5) In the scanning probe microscope described in any of Items 2 to 4, the control device relatively moves the probe back and forth in a first direction perpendicular to the height direction of the sample and in a second direction opposite to the first direction, along the same measurement path of the sample, to acquire measurement data of the sample, stores the first measurement data acquired by moving the probe in the first direction and the second measurement data acquired by moving the probe in the second direction along the same measurement path, and, if the physical quantity does not become constant, identifies the cause why the physical quantity did not become constant based on the stored first measurement data and second measurement data, and stores cause information that can identify the identified cause.

[0103] With this configuration, cause information can be identified based on the first measurement data and the second measurement data.

[0104] (Item 6) In the scanning probe microscope described in Item 5, when the degree of coincidence between the first measurement data and the data obtained by reversing the time series of the second measurement data is equal to or greater than a threshold, the control device executes, as a second control, a control for setting the measurement range of the sample to a measurement range excluding the areas where the physical quantity is not constant.

[0105] With this configuration, if the degree of coincidence is equal to or greater than the threshold, it is highly likely that the sample contains a convex or concave portion that cannot be measured by a scanning probe microscope. Since measurement is impossible in a measurement range that includes the location where such a convex or concave portion exists, the sample can be properly measured by setting a measurement range that excludes the location where the convex or concave portion exists.

[0106] (Item 7) In the scanning probe microscope according to item 6, the measurement range that is set is a range adjacent to the location.

[0107] With this configuration, it is possible to minimize the drive amount of the first drive mechanism when changing the range.

[0108] (Item 8) In the scanning probe microscope described in any one of Items 5 to 7, the control device executes, as the second control, a process of stopping measurement of the sample for a predetermined waiting time when the degree of coincidence between the first measurement data and the data obtained by reversing the time series of the second measurement data is less than a threshold.

[0109] According to this configuration, the scanning probe microscope resumes measuring the sample after the waiting time has elapsed, and therefore it is possible to perform measurements on the sample S with reduced effects of thermal drift.

[0110] (Item 9) In the scanning probe microscope described in any of Items 5 to 7, when the degree of match between the first measurement data and the second measurement data in reversed time series is less than a threshold, the control device calculates a first measurement difference value based on the first measurement data and the second measurement data in a first measurement path of the sample, calculates a second measurement difference value based on the first measurement data and the second measurement data in a second measurement path of the sample, obtains the elapsed time from when the relative reciprocating movement of the probe ends in the first measurement path to when the relative reciprocating movement of the probe ends in the second measurement path, calculates a waiting time based on the first measurement difference value, the second measurement difference value, and the elapsed time, and performs the process of stopping measurement of the sample for the calculated waiting time, as the second control.

[0111] With this configuration, it is possible to calculate the waiting time according to the amount of thermal drift that is occurring. Furthermore, since the scanning probe microscope resumes measuring the sample after the waiting time has elapsed, it is possible to perform measurements on the sample S with the effects of thermal drift reduced.

[0112] (Item 10) In the scanning probe microscope according to any one of Items 5 to 9, the control device stops measuring the sample when the first measurement data and the second measurement data are not stored.

[0113] With this configuration, if the first and second measurement data are not stored, for example, if one reciprocating movement is not completed, the cause cannot be identified. In this case, the measurement of the sample can be stopped, thereby ensuring safety.

[0114] (Section 11) Any of Sections 5 to 10 In the scanning probe microscope, The control device performs notification based on the cause information.

[0115] This configuration allows the user to recognize that a cause has occurred. (Item 12) In the scanning probe microscope described in any one of Items 2 to 11, the control device can switch between a first mode in which the measurement of the sample is stopped and then resumed, and a second mode in which the measurement of the sample is stopped and then not resumed, by user input.

[0116] With this configuration, the user can select either a first mode in which the sample measurement is stopped and then resumed, or a second mode in which the sample measurement is stopped and then not resumed.

[0117] (Item 13) Another aspect of the control method is a control method for a scanning probe microscope that measures a sample, and that includes a sample stage on which a sample is placed, a probe placed opposite the sample, and a first drive mechanism that moves the probe relatively along the surface of the sample, the control method comprising: executing a first control that keeps a physical quantity acting between the probe and the sample constant; and stopping measurement of the sample if the physical quantity does not become constant despite the execution of the first control.

[0118] With this configuration, even if the physical quantity acting between the probe and the sample is not constant, the measurement of the sample is stopped, thereby reducing the possibility of obtaining inaccurate measurement results.

[0119] It should be noted that, with regard to the above-mentioned embodiments and modified examples, it has been planned from the beginning of the application that the configurations described in the embodiments may be appropriately combined, including combinations not mentioned in the specification, within the scope that does not cause inconvenience or contradiction.

[0120] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0121] 1 optical system, 2 cantilever, 3 probe, 4 holder, 5 beam splitter, 6 laser light source, 7 reflecting mirror, 8 photodetector, 10 measuring device, 12 fine movement mechanism, 13 coarse movement mechanism, 14 sample stage, 20 information processing device, 22 feedback signal generating unit, 30 display device, 30A display area, 40 input device, 100 scanning probe microscope, 102 input unit, 104 processing unit, 106 drive unit, 162 ROM, 164 RAM.

Claims

1. 1. A scanning probe microscope for measuring a sample, comprising: a sample stage on which the sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by executing a first control so that a physical quantity acting between the probe and the sample is constant; a control device that stops the measurement of the sample when the physical quantity does not become constant despite the execution of the first control, The control device includes: a first direction perpendicular to a height direction of the sample and a second direction opposite to the first direction are perpendicular to the height direction of the sample, and the probe is moved back and forth relative to the first direction along the same measurement path of the sample to obtain measurement data of the sample; when the physical quantity is not constant, if a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-series reversed data of second measurement data acquired by moving the probe in the second direction is greater than a threshold, cause information indicating a cause that the sample has an excessively large concave portion or an excessively large convex portion is stored; When the physical quantity does not become constant and the degree of coincidence is smaller than the threshold value, cause information indicating that a cause is that thermal drift of the scanning probe microscope is occurring is stored.

2. A scanning probe microscope for measuring a sample, comprising: a sample stage on which the sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by executing a first control so that a physical quantity acting between the probe and the sample is constant; a control device that stops the measurement of the sample when the physical quantity does not become constant despite the execution of the first control, The control device includes: a first direction perpendicular to a height direction of the sample and a second direction opposite to the first direction are perpendicular to the height direction of the sample, and the probe is moved back and forth relative to the first direction along the same measurement path of the sample to obtain measurement data of the sample; executing a second control for setting a measurement range of the sample to a measurement range excluding a portion where the physical quantity did not become constant when a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-series reversed data of second measurement data acquired by moving the probe in the second direction is greater than a threshold value when the physical quantity does not become constant; After executing the second control, the scanning probe microscope resumes measurement of the sample.

3. A scanning probe microscope for measuring a sample, comprising: a sample stage on which the sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by executing a first control so that a physical quantity acting between the probe and the sample is constant; a control device that stops the measurement of the sample when the physical quantity does not become constant despite the execution of the first control, The control device includes: a first direction perpendicular to a height direction of the sample and a second direction opposite to the first direction are perpendicular to the height direction of the sample, and the probe is moved back and forth relative to the first direction along the same measurement path of the sample to acquire measurement data of the sample; executing a second control for stopping measurement of the sample for a predetermined waiting time when a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-reversed data of second measurement data acquired by moving the probe in the second direction is smaller than a threshold value when the physical quantity is not constant; After executing the second control, the scanning probe microscope resumes measurement of the sample.

4. A scanning probe microscope for measuring a sample, comprising: a sample stage on which the sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along the surface of the sample by executing a first control so that a physical quantity acting between the probe and the sample is constant; a control device that stops the measurement of the sample when the physical quantity does not become constant despite the execution of the first control, The control device includes: a first direction perpendicular to a height direction of the sample and a second direction opposite to the first direction are perpendicular to the height direction of the sample, and the probe is moved back and forth relative to the first direction along the same measurement path of the sample to acquire measurement data of the sample; When the physical quantity is not constant, if a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-reversed data of second measurement data acquired by moving the probe in the second direction is smaller than a threshold value, calculating a first measurement difference value based on the first measurement data and the second measurement data in a first measurement path of the sample; calculating a second measurement difference value based on the first measurement data and the second measurement data in a second measurement path of the sample; acquiring an elapsed time from when the relative reciprocating movement of the probe ends in the first measurement path to when the relative reciprocating movement of the probe ends in the second measurement path; calculating a standby time based on the first measurement difference value, the second measurement difference value, and the elapsed time; executing a second control for stopping the measurement of the sample for the calculated waiting time; After executing the second control, the scanning probe microscope resumes measurement of the sample.

5. The control device includes: if the physical quantity does not become constant, stopping the measurement of the sample and then executing a second control; 2. The scanning probe microscope according to claim 1, wherein measurement of the sample is resumed after the second control is executed.

6. the scanning probe microscope further includes a second drive mechanism that executes a retraction process to increase a distance between the probe and the sample stage; The scanning probe microscope according to claim 5 , wherein the second control includes the retraction process.

7. The first drive mechanism includes: Driving the sample stage in response to the applied voltage; When the applied voltage is zero, the sample stage is driven to an initial position; 7. The scanning probe microscope according to claim 5, wherein the second control includes a process of setting a voltage applied to the first driving mechanism to zero.

8. 3. The scanning probe microscope according to claim 2, wherein the set measurement range is a range adjacent to the location.

9. 9. The scanning probe microscope according to claim 1, wherein the control device stops the measurement of the sample when the first measurement data and the second measurement data are not stored.

10. The scanning probe microscope according to claim 1 , wherein the control device executes a notification based on the cause information.

11. The control device includes: a first mode in which the measurement of the sample is stopped and then resumed; 11. The scanning probe microscope according to claim 1, wherein a first mode is switchable by a user input between a first mode in which the measurement of the sample is stopped and a second mode in which the measurement of the sample is not resumed.

12. a sample stage on which a sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along a surface of the sample, the method comprising: The control method includes: executing a first control such that a physical quantity acting between the probe and the sample becomes constant; stopping the measurement of the sample when the physical quantity does not become constant despite the execution of the first control; Acquiring measurement data of the sample by relatively reciprocating the probe in a first direction perpendicular to a height direction of the sample and in a second direction opposite to the first direction along the same measurement path of the sample; storing cause information indicating a cause that the sample has an excessively large concave portion or an excessively large convex portion when a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-series reversed data of second measurement data acquired by moving the probe in the second direction is greater than a threshold value when the physical quantity is not constant; and storing cause information indicating that a cause is that thermal drift is occurring in the scanning probe microscope when the physical quantity does not become constant and the degree of coincidence is smaller than the threshold value.

13. A sample stage on which a sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along a surface of the sample, the method comprising: The control method includes: executing a first control such that a physical quantity acting between the probe and the sample becomes constant; stopping the measurement of the sample when the physical quantity does not become constant despite the execution of the first control; Acquiring measurement data of the sample by relatively reciprocating the probe in a first direction perpendicular to a height direction of the sample and in a second direction opposite to the first direction along the same measurement path of the sample; executing a second control for setting a measurement range of the sample to a measurement range excluding a portion where the physical quantity does not become constant when a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-series reversed data of second measurement data acquired by moving the probe in the second direction is greater than a threshold value when the physical quantity does not become constant; and resuming measurement of the sample after performing the second control.

14. A sample stage on which a sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along a surface of the sample, the method comprising: The control method includes: executing a first control such that a physical quantity acting between the probe and the sample becomes constant; stopping the measurement of the sample when the physical quantity does not become constant despite the execution of the first control; Acquiring measurement data of the sample by relatively reciprocating the probe in a first direction perpendicular to a height direction of the sample and in a second direction opposite to the first direction along the same measurement path of the sample; executing a second control for stopping measurement of the sample for a predetermined waiting time when a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-reversed data of second measurement data acquired by moving the probe in the second direction is smaller than a threshold value when the physical quantity is not constant; and resuming measurement of the sample after performing the second control.

15. A sample stage on which a sample is placed; A probe disposed facing the sample; a first drive mechanism that relatively moves the probe along a surface of the sample, the method comprising: The control method includes: executing a first control such that a physical quantity acting between the probe and the sample becomes constant; stopping the measurement of the sample when the physical quantity does not become constant despite the execution of the first control; Acquiring measurement data of the sample by relatively reciprocating the probe in a first direction perpendicular to a height direction of the sample and in a second direction opposite to the first direction along the same measurement path of the sample; When the physical quantity is not constant, if a degree of agreement between first measurement data acquired by moving the probe in the first direction and time-reversed data of second measurement data acquired by moving the probe in the second direction is smaller than a threshold value, calculating a first measurement difference value based on the first measurement data and the second measurement data in a first measurement path of the sample; calculating a second measurement difference value based on the first measurement data and the second measurement data in a second measurement path of the sample; acquiring an elapsed time from when the relative reciprocating movement of the probe ends in the first measurement path to when the relative reciprocating movement of the probe ends in the second measurement path; calculating a standby time based on the first measurement difference value, the second measurement difference value, and the elapsed time; executing a second control of stopping the measurement of the sample for the calculated waiting time; and resuming measurement of the sample after performing the second control.

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