Scanning probe microscope and program

Abstract

In a scanning probe microscope according to an embodiment of the present disclosure, a region of a sample subject to observation is divided into a plurality of regions, and a scanner is driven to scan the surface of the sample region-by-region. A data processing unit acquires a plurality of items of image data respectively corresponding to each of the plurality of regions. An input means receives user input relating to acquisition conditions for the plurality of items of image data. The acquisition conditions include scanner-scanning conditions. When the input means receives user input for any two variables from among the following three variables: the scanning range of the scanner for each item of data; the spacing between two adjacent scanning ranges; and the maximum number of fields-of-view that can be acquired from the maximum scanning range of the scanner, a data processing unit calculates the remaining variable of the three variables on the basis of the two received variables.

Description

[Technical field]

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

[0002] Japanese Patent Laid-Open Publication No. 2000-275159 (Patent Document 1) discloses a scanning probe microscope (SPM) that has a probe at the tip of a cantilever and brings the probe close to a sample to obtain information about the sample surface. This scanning probe microscope generates image data based on the obtained information and displays an observation image of the sample surface based on the image data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-275159 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the observation area of ​​the sample surface is larger than the observation field (scanning range) of the scanning probe microscope, the observation area is divided into multiple regions, and the surface shape of each region is observed. In this case, in order to acquire multiple image data corresponding to each of the multiple regions, it is necessary to set the scanning range of the sample surface for each image data. Specifically, in order to arrange multiple scanning ranges side by side within the observation area, the user needs to perform the work of positioning each scanning range and the work of setting the amount of movement of the sample stage on which the sample is placed in order to transition from one scanning range to another. As a result, there is a concern that the workload of the user will increase as the number of image data to be acquired increases.

[0005] The present disclosure has been made to solve these problems, and its purpose is to reduce the workload of a user in a scanning probe microscope that acquires multiple image data showing the surface shape of an observation area of ​​a sample by scanning the observation area. [Means for solving the problem]

[0006] A scanning probe microscope according to an embodiment of the present disclosure includes a probe disposed facing a surface of a sample, a scanner for moving the relative position between the sample and the probe, a drive unit configured to divide an observation target area of ​​the sample into a plurality of areas and drive the scanner to scan the surface of the sample for each area, a data processing unit configured to acquire a plurality of image data corresponding to the plurality of areas as observation images of the observation target area, and an input unit configured to accept a user input regarding conditions for acquiring the plurality of image data. The data processing unit is configured to set the conditions based on the user input. The conditions include a scanning condition of the scanner. When the input unit accepts user input regarding any two of three variables, namely, the scanning range of the scanner for each image data, the interval between two adjacent scanning ranges, and the maximum number of fields of view that can be acquired from the maximum scanning range of the scanner, the data processing unit calculates the remaining one of the three variables based on the two accepted variables. Effect of the Invention

[0007] According to the present disclosure, in a scanning probe microscope that acquires a plurality of image data indicating the surface shape of an observation target area of ​​a sample by scanning the inside of the observation target area, the workload of a user can be reduced. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a scanning probe microscope according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of an information processing device. [Diagram 3]4 is a flowchart for explaining the procedure of image data acquisition processing executed by a scanning probe microscope. [Figure 4] FIG. 13 is a diagram for explaining a method for setting a plurality of scanning ranges. [Diagram 5] FIG. 2 is a diagram illustrating a first example of a setting screen for setting scanning conditions of a scanner. [Figure 6] 10 is a flowchart illustrating a process for setting scanning conditions of a scanner. [Figure 7] FIG. 11 is a diagram illustrating a second example of a setting screen for setting a scanning screen of the scanner. [Figure 8] FIG. 13 is a diagram illustrating a third example of a setting screen for setting a scanning screen of the scanner. [Figure 9] 10 is a flowchart illustrating a process for setting scanning conditions of a scanner. [Figure 10] FIG. 13 is a diagram illustrating an example of a setting screen for setting an acquisition order of image data. [Figure 11] FIG. 4 is a diagram for explaining an acquisition order of image data. [Figure 12] FIG. 2 is a diagram for explaining a basic concept of an acquisition order of image data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

[0010] [Configuration of a scanning probe microscope] 1 is a diagram showing 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: Automatic Force Microscope) that observes the shape of the surface of a sample S by utilizing an atomic force (attractive or repulsive force) acting between a probe (needle) 3 and the surface of a sample S. The present disclosure can also be similarly applied to other scanning probe microscopes, such as a scanning tunneling microscope (STM: Scanning Tunneling Microscope).

[0011] Referring to FIG. 1, a sample S is fixed on the surface of a hard and flat substrate 15. In this embodiment, the sample S is a powder sample composed of fine particles. The sample S may be any sample containing powder, and may be, for example, a liquid sample containing powder. The substrate 15 is made of glass, mica, a silicon wafer, or the like. The scanning probe microscope 100 according to this embodiment can be used for particle analysis of powder samples, etc.

[0012] The scanning probe microscope 100 comprises, as its main components, an observation device 10, an information processing device 20, a display device 30, and an input device 40. The observation device 10 comprises, as its main components, an optical system 1, a cantilever 2, a scanner 12, a sample holder 14, an XY-direction driver 16, a Z-direction driver 18, a feedback signal generator 22, and a scanning signal generator 24.

[0013] The scanner 12 has a cylindrical shape and is a moving device for changing the relative positional relationship between the sample S and the probe 3. The substrate 15 on which the sample S is placed is held by a sample holder 14 provided on the scanner 12. The scanner 12 has an XY scanner 12xy that moves the sample S in two mutually orthogonal X and Y axis directions in a plane parallel to the upper surface of the sample holder 14, and a Z scanner 12z that slightly moves the sample S in a Z axis direction orthogonal to the X and Y axes. The XY scanner 12xy has a piezoelectric element that is deformed by a voltage applied from an XY direction driver 16. The Z scanner 12z has a piezoelectric element that is deformed by a voltage applied from a Z direction driver 18. Note that the XY scanner 12xy and the Z scanner 12z are not limited to piezoelectric elements.

[0014] The cantilever 2 is formed in the shape of a leaf spring, and one end of the cantilever 2 is supported by a holder 4. The other end of the cantilever 2 is a free end, and is disposed above the sample S in the Z-axis direction. The cantilever 2 has a front surface facing the sample S and a back surface opposite 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. A reflective surface that reflects light is provided on the back surface of the tip. The tip of the cantilever 2 is displaced in the Z-axis direction due to the atomic force acting between the probe 3 and the sample S on the other side of the probe 3.

[0015] An optical system 1 for detecting the amount of bending of the cantilever 2 (i.e., the amount of displacement of the tip) is provided above the cantilever 2 in the Z-axis direction. When observing a sample S, the optical system 1 irradiates a laser light onto the back surface (reflecting surface) of the cantilever 2 and detects the laser light 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.

[0016] The laser light source 6 has a laser oscillator that emits a laser beam. The photodetector 8 has a photodiode that detects the incident laser beam. The laser beam LA emitted from the laser light source 6 is reflected by the beam splitter 5 and irradiated onto the rear surface (reflection surface) of the cantilever 2. The laser beam reflected by the rear surface of the cantilever 2 is further reflected by the reflecting mirror 7 and enters the photodetector 8.

[0017] Photodetector 8 has a light receiving surface divided into multiple (usually two) parts in the Z-axis direction (displacement direction) of cantilever 2. Alternatively, photodetector 8 has a light receiving surface 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.

[0018] The feedback signal generating unit 22 calculates the amount of deflection of the cantilever 2 by processing 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 always constant. 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 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.

[0019] The scanning signal generating unit 24 calculates a voltage value Vx in the X-axis direction and a voltage value Vy in the Y-axis direction so that the sample S moves in the X-axis and Y-axis directions relative to the probe 3 according to preset scanning conditions. The scanning signal generating unit 24 outputs a signal indicating the calculated voltage values ​​Vx and Vy 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. The scanning conditions include information on the scanning range (i.e., the observation field of view) in the XY plane, the scanning direction, and the scanning speed. The scanning conditions will be described in detail later.

[0020] The information processing device 20 mainly controls the operation of the observation device 10, and includes a data processing unit 26 and a storage unit .

[0021] A signal indicating the feedback amount in the Z-axis direction (applied voltage Vz and deviation Sd to Z scanner 12z) is sent from Z-axis direction driver 18 to data processor 26 and stored in memory 28. Data processor 26 calculates the displacement amount of sample S in the Z-axis direction from voltage Vz based on correlation information indicating the relationship between voltage Vz and the corresponding displacement amount of sample S in the Z-axis direction, which is previously stored in memory 28. The calculated displacement amount reflects a value indicating the position of sample S in the Z-axis direction (hereinafter also referred to as "Z value"). Data processor 26 creates three-dimensional image data representing the shape of the surface of sample S by calculating the displacement amount of sample S in the Z-axis direction at each position in the X-axis and Y-axis directions in the scanning range.

[0022] This image data 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 surface height at each position on the substrate 15, and at the position where the sample S is present, the Z value corresponds to the height including the sample S. The data processing unit 26 displays the created image data on the display device 30 and stores it in the storage unit 28.

[0023] [Hardware configuration of information processing device] 2 is a diagram showing an example of a hardware configuration of the information processing device 20. Referring to FIG. 2, the information processing device 20 has, as main components, a central processing unit (CPU) 160, a read only memory (ROM) 162, a random access memory (RAM) 164, a hard disk drive (HDD) 166, a communication interface (I / F) 168, a display I / F 170, and an input I / F 172. The 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 observation 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.

[0024] The communication I / F 168 is an interface for communicating with the observation 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.

[0025] ROM 162 stores programs executed by CPU 160. RAM 164 can temporarily store data generated by execution of the programs in CPU 160 and data input via communication I / F 168. RAM 164 can function as a temporary data memory used as a working area. HDD 166 is a non-volatile storage device. Instead of HDD 166, a semiconductor storage device such as a flash memory may be adopted.

[0026] 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 in a storage medium or via the Internet or the like. The information processing device 20 stores the read program in a predetermined storage area (for example, ROM 162). The CPU 160 executes the program to perform image data acquisition processing, which will be described later.

[0027] The display device 30 can display a setting screen for setting image data acquisition conditions. During acquisition of image data, the display device 30 can display image data created by the information processing device 20 and data obtained by processing this image data.

[0028] The input device 40 accepts inputs including instructions from a user (e.g., an analyst) to the information processing device 20. The input device 40 includes a keyboard, a mouse, and a touch panel that is integral with the display screen of the display device 30, and accepts image acquisition conditions and the like.

[0029] [Operation of a scanning probe microscope] Next, the operation of the scanning probe microscope 100 shown in FIG. 1 will be described.

[0030] In this embodiment, in order to evaluate the particle size of a sample S (powder sample), a scanning probe microscope 100 is used to obtain image data that is an observation image of the surface shape of the sample S.

[0031] Here, in the scanning probe microscope 100, the scanning range (imaging field of view) on the XY plane is limited by the movable range of the piezoelectric element included in the XY scanner 12xy. Therefore, when the observation target area on the surface of the sample S is wider than the scanning range of the scanning probe microscope 100, the observation target area is divided into a plurality of areas, and the surface shape of each area is observed. In this case, the scanning probe microscope 100 is configured to move (offset) the scanning range in the X-axis and / or Y-axis directions each time image data for one scanning range (imaging field of view) is acquired, in order to observe the plurality of areas successively in order. As a result, a plurality of image data corresponding to each of the plurality of areas is created one by one in order.

[0032] In order to automatically and continuously acquire such a plurality of image data, conditions for acquiring the plurality of image data are first set in the scanning probe microscope 100. The acquisition conditions for the plurality of image data include conditions related to the scanning of the scanner 12, conditions related to the acquisition order of the plurality of image data, conditions related to the processing of the acquired image data, and conditions related to the display of the image data. The information processing device 20 controls the operation of the observation device 10 according to the set conditions, so that a plurality of image data can be acquired for the observation target region.

[0033] Fig. 3 is a flow chart for explaining the procedure of the image data acquisition process executed by the scanning probe microscope 100. As shown in Fig. 3, the image data acquisition process includes a step (S01) of setting image data acquisition conditions, a step (S02) of tuning the cantilever 2, a step (S03) of acquiring image data, a step (S04) of processing and extracting the image data, a step (S05) of saving the image data, and a step (S06) of displaying the image data. The process of each step will be explained below.

[0034] (1) Step of setting image data acquisition conditions (S01 in FIG. 3) In the step of setting the image data acquisition conditions (S01 in FIG. 3), the tuning conditions of the cantilever 2 (S10), the scanning conditions of the scanner 12 (S11), the acquisition order of the image data (S12), the processing conditions of the image data (S13), the processing conditions of the particle analysis (S14), and the display conditions of the image data and the data based thereon (e.g., particle size distribution data, etc.) (S15) are set. Note that the conditions set in step S01 are not limited to these. The order in which these conditions are set is also not limited, and the user can set them in any order. In this embodiment, the display device 30 is configured to be able to display a setting screen for setting the image data acquisition conditions. The user can set various conditions on the setting screen by operating the input device 40.

[0035] (1-1) Cantilever tuning conditions (S10) The tuning conditions (S10) of the cantilever 2 are conditions that are set when the operation mode of the scanning probe microscope 100 is the dynamic mode. The tuning conditions include items such as the type of cantilever 2, the frequency range and amplitude for exciting the cantilever 2, etc. The user can set each item using the input device 40.

[0036] In the dynamic mode, the cantilever 2, which is brought close to the surface of the sample S, is excited at a frequency near its resonance point. The amplitude of the vibration of the cantilever 2 changes due to the atomic force acting between the probe 3 and the surface of the sample S. The feedback signal generating unit 22 (see FIG. 1) feedback controls the Z scanner 12z to slightly move the sample S in the Z-axis direction so that the amplitude of this vibration remains constant. By processing the control amount for this feedback control in the data processing unit 26, image data of the surface shape of the sample S can be created.

[0037] (1-2) Scanning conditions of the scanner (S11) In setting the scanning conditions of the scanner 12 (S11), conditions related to the movement of the XY scanner 12xy in the X-axis and Y-axis directions are set. As described above, when the observation target area on the surface of the sample S is divided into a plurality of areas, a plurality of scanning ranges are set corresponding to the plurality of areas, respectively. Fig. 4 is a diagram for explaining a method of setting a plurality of scanning ranges.

[0038] 4, the XY scanner 12xy can deform in the positive and negative directions of the X axis with X=0 as the center, and can deform in the positive and negative directions of the Y axis with Y=0 as the center. This allows the sample S to move in the positive and negative directions of the X axis and the positive and negative directions of the Y axis with the origin (0,0) of the XY plane as the center. The amount of movement (amount of deformation) in each of the X and Y axes can be controlled by the voltages Vx and Vy applied to the XY scanner 12xy. The origin (0,0) indicates a state (initial state) in which the amount of movement (amount of deformation) in the X axis direction and the amount of movement (amount of deformation) in the Y axis direction are both zero.

[0039] The maximum scanning range Rmax of the XY scanner 12xy is shown in Figure 4. The maximum scanning range Rmax has a square shape centered on the origin (0,0). The length Lmax of one side of this square is determined by the movable range of the XY scanner 12xy in the X and Y axis directions.

[0040] In step S11, multiple scanning ranges R can be set within the maximum scanning range Rmax. One scanning range R corresponds to the range in which the XY scanner 12xy moves the probe 3 and the sample S relatively to create one image data. In other words, one scanning range R corresponds to the range in which the probe 3 scans the surface of the sample S to create one image data. The scanning range R has a square shape with a side length of L.

[0041] As shown in Fig. 4, multiple scanning ranges R are arranged at equal intervals in the X- and Y-axis directions with the origin (0,0) as the center. Specifically, one scanning range R1 of the multiple scanning ranges R is arranged so that its center is located on the origin (0,0). Then, multiple scanning ranges R are arranged side by side at intervals D in the X- and Y-axis directions with scanning range R1 as the center. In the example of Fig. 4, a total of nine scanning ranges R are arranged in a 3 x 3 matrix with scanning range R1 as the center.

[0042] In this way, by arranging the scanning range R1 at the origin (0,0) and arranging multiple scanning ranges R at the center of this scanning range R1, within the maximum scanning range Rmax, the scanning ranges R are arranged evenly in the positive and negative directions of the X axis, and the scanning ranges R are arranged evenly in the positive and negative directions of the Y axis. This makes it possible to observe the observation area on the surface of the sample S evenly using multiple scanning ranges R (observation field of view).

[0043] As shown by the dotted line in Fig. 4, a square having at least a part exceeding the maximum scanning range Rmax is not set as the scanning range R. In this specification, the maximum number of scanning ranges R (observation fields of view) that can be obtained from the maximum scanning range Rmax is defined as the "maximum number of fields of view Nmax." In the example of Fig. 4, the maximum number of fields of view Nmax=9.

[0044] As described above, since the maximum scanning range Rmax is a fixed value based on the movable range of the XY scanner 12xy, the maximum number of fields of view Nmax is determined according to the length L of the scanning range R and the interval D between adjacent scanning ranges R. In other words, the maximum number of fields of view Nmax, the length L of the scanning range R, and the interval D of the scanning ranges R have a relationship such that when the values ​​of any two of these three variables are determined, the remaining variable is uniquely determined.

[0045] In step S11, the relationship between these three variables is utilized to simplify the input operation by the user. Specifically, the input operation by the user can be performed using a setting screen for setting the scanning conditions, which is displayed on the display device 30. Fig. 5 is a diagram showing a schematic diagram of a first example of the setting screen for setting the scanning conditions of the scanner 12.

[0046] As shown in Fig. 5, the setting screen displays a tab 50 for setting the value of the scanning range R (length L), a tab 52 for setting the value of the interval D of the scanning range R, a tab 54 for setting the value of the maximum number of fields of view Nmax, a tab 56 for setting the value of the number of pieces of image data N to be acquired, and a tab 58 for setting the value of the scanning speed. Note that the input means for accepting the setting of the scanning conditions by the user is not limited to the tabs, and any interface (such as a GUI (Graphical User Interface)) can be used. Note that the scanning speed is the scanning speed of one line. The scanning speed when one line is scanned back and forth in one second is 1 [Hz].

[0047] All of the tabs shown in the setting screen of Fig. 5 are configured to be able to receive input from the user. Note that tabs 50 and 52 each have a tab for switching the unit of numerical values ​​(µm / nm).

[0048] The user can input numerical values ​​for each tab using the input device 40. The upper and lower limits of the settable range of the length L of the scanning range R are determined by the movable range of the XY scanner 12xy. The upper limit of the settable range is the length Lmax of one side of the maximum scanning range Rmax. The interval D of the scanning ranges R can have a lower limit of 0. In other words, two adjacent scanning ranges R can be arranged with no interval between them.

[0049] 5, the tab 50 for the scanning range R, the tab 52 for the interval D of the scanning range R, and the tab 54 for the maximum number of fields of view Nmax are configured so that when the user inputs values ​​into any two of the tabs, the value into the remaining tab is automatically calculated. Such a configuration can be realized by the data processing unit 26 executing a calculation process using the relationship between the above-mentioned three variables.

[0050] Specifically, the relationship shown in the following formula (1) is established among the length Lmax of the maximum scanning range Rmax, the length L of the scanning range R, the interval D of the scanning range R, and the maximum number of fields of view Nmax. Lmax ≧ L × Nmax 1 / 2 +D×(Nmax 1 / 2 -1) …(1) Since Lmax on the left side of the above formula (1) is a fixed value, when two of the three variables L, D, and Nmax on the right side are set, the remaining one variable can be calculated. By preparing a relational expression or a table showing the relationship shown in the above formula (1) in advance, the data processing unit 26 can obtain the remaining one variable using the relational expression or table when the two variables are input.

[0051] 6 is a flowchart for explaining the processing procedure for setting (S11 in FIG. 3) the scanning conditions of the scanner 12. The processing procedure of the flowchart in FIG.

[0052] 6, in step S20, data processing unit 26 determines whether or not length L of scanning range R has been input in tab 50 of the scanning condition setting screen shown in Fig. 5. The determinations in step S20 and steps S21, S23, S24, and S26 described below can be made based on a user input transmitted from input device 40 to input I / F 172.

[0053] When the length L of the scanning range R is input to the tab 50 (YES in S20), the data processing unit 26 subsequently determines in step S21 whether or not the interval D of the scanning range R is input to the tab 52 of the setting screen. When the interval D of the scanning range R is input to the tab 52 (YES in S21), the data processing unit 26 calculates the maximum number of fields of view Nmax in step S22 based on the maximum scanning range Rmax set in advance and the length L and interval D of the scanning range R input in steps S20 and S21. The maximum number of fields of view Nmax can be calculated by using a relational expression or a table based on the relationship of the above formula (1). The data processing unit 26 displays the calculated value of the maximum number of fields of view Nmax in the tab 54 of the setting screen.

[0054] On the other hand, if the length L of the scanning range R is not entered in the tab 50 in step S20 (NO in S20), the data processing unit 26 determines in step S23 whether or not the value of the maximum number of fields of view Nmax has been entered in the tab 54 of the setting screen.

[0055] When the maximum number of fields Nmax is input to the tab 54 (YES in S23), the data processing unit 26 subsequently determines in step S24 whether or not the interval D of the scanning range R is input to the tab 52 of the setting screen. When the interval D of the scanning range R is input to the tab 52 (YES in S24), the data processing unit 26 calculates the length L of the scanning range R based on the maximum scanning range Rmax set in advance and the maximum number of fields Nmax and the interval D of the scanning range R input in steps S23 and S24 in step S25. The length L of the scanning range R can be calculated by using a relational expression or a table based on the relationship of the above formula (1). The data processing unit 26 displays the calculated value of the length L of the scanning range R on the tab 50 of the setting screen.

[0056] If the interval D of the scanning range R is not input in the tab 52 in step S21 (NO in S21), the data processing unit 26 determines in step S26 whether or not the value of the maximum number of fields of view Nmax has been input in the tab 54 of the setting screen.

[0057] When the maximum number of fields of view Nmax is input in tab 54 (YES in S26), in step S27, data processing unit 26 calculates interval D of scanning range R based on the preset maximum scanning range Rmax and the length L of scanning range R and maximum number of fields of view Nmax input in steps S20 and S26. Interval D of scanning range R can be calculated by using a relational expression based on the relationship of formula (1) above or a table. Data processing unit 26 displays the calculated value of interval D of scanning range R in tab 52 of the setting screen.

[0058] When the maximum number of fields of view Nmax, the length L of the scanning range R, and the interval D of the scanning range R are set in steps S20 to S27, data processing unit 26 proceeds to step S28 and determines whether or not the number N of image data to be acquired has been input in tab 56 of the setting screen. The number N of image data to be acquired can be set in the range of 1 to Nmax. If the number N of image data to be acquired has been input in tab 56 (YES in S28), data processing unit 26 ends the process.

[0059] The process of setting the scanning conditions is not limited to the setting screen of Fig. 5 and the flowchart of Fig. 6. For example, as the scanning conditions, conditions related to the feedback control executed by the feedback signal generating unit 22, the number of pixels of the image data, etc. can be set.

[0060] (First modified example) 7 is a diagram showing a second example of a setting screen for setting the scanning screen of the scanner 12. The setting screen shown in FIG. 7 is obtained by adding a tab 60 to the setting screen shown in FIG.

[0061] In the tab 60, the lower limit of the settable range of the interval D of the scanning range R is input in advance. This lower limit of the interval D is set to the standard particle diameter of the powder sample that is the sample S. The standard particle diameter of the powder sample can be set based on the known particle size distribution of the powder sample. For example, the standard particle diameter can be set to the average particle diameter in the known particle size distribution. Alternatively, the standard particle diameter can be set to a target value of the particle diameter that is set based on the known particle size distribution.

[0062] Here, when the interval D of the scanning ranges R is smaller than the standard particle diameter of the powder sample, a particle located on the interval D may exist across two adjacent scanning ranges R separated by the interval D. In this case, the particle will be observed overlapping in the two scanning ranges R. As a result, when counting the number of particles present in each observation field, one particle will be counted overlapping in the two scanning ranges R (so-called double counting), which may result in a decrease in the accuracy of the particle count value.

[0063] In the first modified example, the lower limit of the interval D of the scanning range R is set to the standard particle diameter of the sample S, so that the interval D of the scanning range R can be set to a value equal to or larger than the standard particle diameter. This means that a particle located on the interval D will be present only in one of the two scanning ranges R adjacent to the interval D, or will not be present in either of the two scanning ranges R, thereby preventing one particle from being present across two scanning ranges R. This makes it possible to avoid the double counting described above.

[0064] (Second modified example) Fig. 8 is a diagram showing a schematic diagram of a third example of a setting screen for setting a scanning screen of the scanner 12. In the setting screen shown in Fig. 8, the tab 52 in the setting screen shown in Fig. 5 is replaced with a tab 52A.

[0065] In tab 52A, the interval D of the scanning range R is preset to a predetermined value that is equal to or greater than the standard particle diameter of the sample S. In the example of Fig. 8, the interval D is set to the standard particle diameter of the sample S. The interval D may be any value that is equal to or greater than the standard particle diameter of the sample S, and may be, for example, a value obtained by adding a predetermined value to the standard particle diameter, or a value obtained by multiplying the standard particle diameter by a predetermined value.

[0066] In this modified example, by registering in advance the standard particle diameter for each type of powder sample to be the sample S, the standard particle diameter of the sample S can be automatically input into tab 52A when the setting screen of FIG. 8 is displayed on the display device 30.

[0067] 8, the numerical value of tab 52A is preset, so the user can input numerical values ​​for the remaining tabs 50, 54, and 56 using input device 40. At this time, for tab 50 for scanning range R and tab 54 for maximum number of fields of view Nmax, when the user inputs a numerical value for either one of the tabs, the numerical value for the remaining tab is automatically calculated.

[0068] Such a configuration can be realized by the information processing device 20 executing a calculation process using the relationship between the above-mentioned three variables. Specifically, since Lmax and D are fixed values ​​in the relationship shown in the following formula (1), when one of the two variables L and Nmax is set, the data processing unit 26 can calculate the remaining one variable.

[0069] 9 is a flowchart for explaining the processing procedure for setting (S11 in FIG. 3) the scanning conditions of the scanner 12. The processing procedure of the flowchart in FIG.

[0070] 9, in step S30, the data processing unit 26 sets the interval D of the scanning range R in tab 52A of the scanning condition setting screen shown in FIG. 8 to a predetermined value (e.g., the standard particle diameter) that is equal to or greater than the standard particle diameter of the powder sample of the sample S.

[0071] Next, in step S31, the data processing unit 26 determines whether or not the length L of the scanning range R has been input in the tab 50 of the setting screen. The determinations in step S31 and in step S33, which will be described later, can be made based on a user input transmitted from the input device 40 to the input I / F 172.

[0072] When the length L of the scanning range R is input to tab 50 (YES in S31), in step S32, data processing unit 26 calculates the maximum number of fields of view Nmax based on the preset maximum scanning range Rmax, the interval of scanning range R set in step S30, and the length L of scanning range R input in step S21. The maximum number of fields of view Nmax can be calculated by using a relational expression based on the relationship of formula (1) above or a table. Data processing unit 26 displays the calculated value of maximum number of fields of view Nmax in tab 54 of the setting screen.

[0073] On the other hand, if the length L of the scanning range R is not entered in the tab 50 in step S31 (NO in S31), the data processing unit 26 determines in step S33 whether or not the value of the maximum number of fields of view Nmax has been entered in the tab 54 of the setting screen.

[0074] When the maximum number of fields of view Nmax is input in tab 54 (YES in S33), in step S34, data processing unit 26 calculates length L of scanning range R based on the preset maximum scanning range Rmax, interval D of scanning range R set in step S30, and maximum number of fields of view Nmax input in step S33. Length L of scanning range R can be calculated by using a relational expression based on the relationship of formula (1) above or a table. Data processing unit 26 displays the calculated value of length L of scanning range R in tab 50 of the setting screen.

[0075] When the maximum number of fields of view Nmax, the length L of the scanning range R, and the interval D of the scanning range R are set in steps S30 to S34, the data processing unit 26 proceeds to step S35 and determines whether or not the number N of image data to be acquired has been input in tab 56 of the setting screen. If the number N of image data to be acquired has been input in tab 56 (YES in S35), the data processing unit 26 ends the process.

[0076] The process of setting the scanning conditions is not limited to the setting screen of Fig. 8 and the flowchart of Fig. 9. For example, the conditions of the feedback control executed by the feedback signal generating unit 22 and the number of pixels of the image data can be further set as the scanning conditions.

[0077] In this way, in the second modified example, since the interval D between two adjacent scanning ranges R is set in advance to a value equal to or greater than the standard particle diameter of the sample S, the user only needs to input the value of either the length L of the scanning range R or the maximum number of fields of view Nmax. This simplifies the input work of the user. In addition, since the interval D between the scanning ranges R is set to a value equal to or greater than the standard particle diameter of the sample S, the above-mentioned problem of double counting can be avoided.

[0078] (1-3) Image data acquisition sequence (S12 in FIG. 3) In the step of setting the acquisition order of image data (S12 in FIG. 3), the order in which the image data of the number N of acquisitions set in step S11 is acquired is set.

[0079] 10 is a diagram showing an example of a setting screen for setting the acquisition order of image data. The setting screen of FIG.

[0080] As shown in FIG. 10, the settings screen displays a tab 70 for specifying the image data to be acquired first when image data acquisition begins, and a tab 72 for setting the image data acquisition direction.

[0081] Fig. 11 is a diagram for explaining the order of acquiring image data. Fig. 11 shows the order of acquiring image data when the number of pieces of acquired image data N is 9. When the number of pieces of acquired image data N is 9, nine pieces of image data D1 to D9 are acquired corresponding to nine scanning ranges arranged according to the length L and interval D of the scanning range R set in step S11.

[0082] The user can specify the image data to be acquired first among the nine pieces of image data D1 to D9 on the setting screen of Fig. 10. In the example of Fig. 11, it is assumed that the image data D5 located on the origin (0,0) of the XY plane is specified as the first image data.

[0083] When the user designates the first image data D5, the data processing unit 26 sets the acquisition order for the remaining eight pieces of image data. Specifically, the data processing unit 26 sets the acquisition order so that the movement distance of the XY scanner 12xy for acquiring the nine pieces of image data D1 to D9 is the shortest. In the example of Fig. 11, the acquisition order is set so that the image data are acquired in the following order, clockwise: D5 → D8 → D7 → D4 → D1 → D2 → D2 → D3 → D6 → D9.

[0084] When the step of acquiring image data (S03 in FIG. 3) described later is started, the scanning signal generating unit 24 of the information processing device 20 moves the scanning range R of the XY scanner 12xy in accordance with the set acquisition sequence. Specifically, when one piece of image data is acquired for one scanning range R, the scanning signal generating unit 24 moves the scanning range R to acquire the next image data. In this way, by alternately repeating the acquisition of image data and the movement of the scanning range R, the image data are acquired one by one in sequence in accordance with the set acquisition sequence.

[0085] At this time, the scanning signal generating unit 24 calculates the voltage value Vx in the X-axis direction and the voltage value Vy in the Y-axis direction with the start position of the next scanning range R as a target value, and outputs the calculated voltage values ​​Vx and Vy to the XY direction driving unit 16. When open-loop control is used to drive the XY scanner 12xy by the XY direction driving unit 16, the XY scanner 12xy can be moved at a higher speed than when feedback control is used to control the movement of the XY scanner 12xy while detecting the current position. On the other hand, if the movement amount of the XY scanner 12xy becomes large, there is a concern that a deviation may occur between the target position and the actual position. In order to suppress this deviation, it is necessary to reduce the movement amount of the XY scanner 12xy.

[0086] Therefore, the information processing device 20 sets the acquisition order of the N pieces of image data so as to minimize the moving distance of the XY scanner 12xy. Fig. 12 is a diagram for explaining the basic concept of the acquisition order of the image data.

[0087] As shown in Fig. 12, when acquiring the next image data after acquiring image data for one scanning range R, the scanning signal generating unit 24 is configured to move the XY scanner 12xy to a scanning range adjacent to the scanning range in the Y-axis direction or to a scanning range adjacent to the scanning range in the X-axis direction. In the example of Fig. 12, the moving directions of the scanning range are set as P1 for the negative direction of the Y-axis, P2 for the negative direction of the X-axis, P3 for the positive direction of the Y-axis, and P4 for the positive direction of the X-axis. When the image data acquisition direction is set to clockwise, the priority is set for the moving directions of the scanning range in the order of P1, P2, P3, and P4.

[0088] When the first image data D1 is acquired, the scanning signal generating unit 24 moves the scanning range of the XY scanner 12xy in the direction P1. When the second image data D2 is acquired for the scanning range after the movement, the scanning signal generating unit 24 further moves the scanning range in the direction P1. As in FIG. 12, when there is no adjacent scanning range in the direction P1, the scanning signal generating unit 24 moves the scanning range in the direction P2. When the third image data D3 is acquired for the scanning range after the movement, the scanning signal generating unit 24 further moves the scanning range in the direction P2. As in FIG. 12, when there is no adjacent scanning range in the direction P2, the scanning signal generating unit 24 moves the scanning range in the direction P3. When the fourth image data D3 is acquired for the scanning range after the movement, the scanning signal generating unit 24 further moves the scanning range in the direction P3. As in FIG. 12, when there is no adjacent scanning range in the direction P3, the scanning signal generating unit 24 moves the scanning range in the direction P4. In the example of Fig. 12, four pieces of image data D1 to D4 are acquired in clockwise order. Although not shown, if the image data acquisition direction is set to counterclockwise, the priority may be set in the order of P1, P4, P3, and P2 for the four movement directions P1 to P4 shown in Fig. 12.

[0089] 10, the user can set the scanning range of the image data to be acquired first in tab 70 indicating the start of acquisition, and can set the acquisition direction of the image data (clockwise / counterclockwise) in tab 72 indicating the acquisition direction. When data processing unit 26 receives user input from input device 40, it sets the acquisition order of N pieces of image data based on the concepts described in FIGS. 11 and 12.

[0090] (1-4) Image data processing conditions (S13 in FIG. 3) Returning to FIG. 3, in the step of setting the image data processing conditions (S13 in FIG. 3), the user can set conditions related to the processing of the acquired image data. As conditions related to the processing of the image data, the user can set the type of signal to be the subject of image processing. The target signals include a signal indicating a Z value (height signal), a signal indicating deviation Sd, and the like. In addition, as the content of data processing, the user can set whether or not to perform tilt correction of the image data, and the like.

[0091] (1-5) Processing conditions for particle analysis (S14 in Fig. 3) In the step of setting the processing conditions for particle analysis (S14 in FIG. 3), the user can set conditions related to the processing of the acquired image data. As conditions related to the processing of the image data, the user can set the range (upper limit and / or lower limit) of the Z value of the data to be extracted from the image data that has been subjected to the image processing in step S13.

[0092] In an observation image shown by a single image data, the positions where particles are present have different heights from positions where particles are not present, and therefore the Z values ​​will also be different. Therefore, by appropriately setting the range of Z values, it is possible to identify the positions where particles are present. This makes it possible to calculate the number of particles present in the image data. Furthermore, by executing a process to calculate the particle size of each particle based on the Z value (height) at each position in the image data, it is possible to create particle size distribution data for the sample S.

[0093] (1-6) Display conditions (S15 in Figure 3) In the step of setting display conditions (S15 in FIG. 3), the user can set conditions related to the display of image data. In this step, the user can set a method for displaying image data and particle size distribution data generated by particle analysis.

[0094] (2) The process of tuning the cantilever (S02 in Fig. 3) When the data acquisition conditions are set in step S01, the information processing device 20 starts acquiring image data in response to a user input instructing the start of image data acquisition. The information processing device 20 first tunes the cantilever 2 in step S02. When the operation mode of the scanning probe microscope 100 is the dynamic mode, the cantilever 2 is excited according to the tuning conditions of the cantilever 2 set in step S10.

[0095] (3) A step of acquiring image data (S03 in FIG. 3). In step S03, the information processing device 20 (scanning signal generating unit 24) drives the XY scanner 12xy in accordance with the scanning conditions of the scanner 12 set in step S10 and the acquisition sequence of the image data set in step S12.

[0096] The data processing unit 26 sequentially acquires N pieces of image data by creating image data for each scanning range based on a signal indicating the feedback amount in the Z-axis direction (the applied voltage Vz and the deviation Sd to the Z scanner 12z) transmitted from the feedback signal generating unit 22.

[0097] (4) Processing and extracting image data (S04 in FIG. 3) In step S04, the information processing device 20 processes the acquired image data each time one piece of image data is acquired according to the image data processing conditions set in step S13. The information processing device 20 further extracts data within the Z value range set in the particle analysis processing conditions in step S14 from the processed image data. Based on the extracted data, the number of particles contained in one piece of image data can be calculated.

[0098] (5) A process of storing image data (S05 in FIG. 3). In step S05, the information processing device 20 stores the N pieces of image data that have been subjected to image processing and data based thereon in the storage unit 28 as data indicating the surface shape of the observation target region of the sample S.

[0099] (6) A step of displaying image data (S06 in FIG. 3). In step S06, information processing device 20 causes display device 30 to display the image data according to the display conditions set in step S15.

[0100] As described above, according to the control method for a scanning probe microscope according to the present embodiment, in the step of setting conditions for acquiring a plurality of image data (S01 in FIG. 3), the input work by the user for setting a plurality of scanning ranges respectively corresponding to the plurality of image data can be simplified, thereby reducing the workload on the user.

[0101] In addition, in the step of setting the scanning conditions (S11 in FIG. 3), the interval between two adjacent scanning ranges is restricted to a value equal to or larger than the standard particle diameter of the powder sample, which prevents the same particles from being observed in two adjacent scanning ranges. This makes it possible to accurately calculate the number of particles present in each observation field.

[0102] Furthermore, in the step of setting the image data acquisition order (S12 in FIG. 3), the acquisition order of the multiple image data is set so that the distance traveled by the XY scanner 12xy to continuously acquire multiple image data is minimized, thereby making it possible to suppress deviation of the movement amount of the XY scanner 12 under open loop control from the target value, thereby reducing the influence of movement of the observation field of view.

[0103] [Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0104] (Item 1) A scanning probe microscope according to one embodiment includes a probe arranged to face a surface of a sample, a scanner for moving the relative position between the sample and the probe, a drive unit configured to divide an observation target area of ​​the sample into a plurality of areas and drive the scanner to scan the surface of the sample for each area, a data processing unit configured to acquire a plurality of image data corresponding to the plurality of areas as observation images of the observation target area, and an input means for receiving a user input regarding conditions for acquiring the plurality of image data. The data processing unit is configured to set the conditions based on the user input. The conditions include a scanning condition of the scanner. When the input means receives user input regarding any two of three variables, namely, the scanning range of the scanner for each image data, the interval between two adjacent scanning ranges, and the maximum number of fields of view that can be acquired from the maximum scanning range of the scanner, the data processing unit calculates the remaining one of the three variables based on the two received variables.

[0105] According to the scanning probe microscope described in paragraph 1, the input work by the user for setting a plurality of scanning ranges respectively corresponding to a plurality of image data can be simplified, thereby reducing the workload of the user.

[0106] (Item 2) In the scanning probe microscope according to item 1, the sample is a sample containing powder. The data processing unit sets a lower limit of a variable corresponding to the interval of the scanning range to a standard particle diameter of the powder.

[0107] According to the scanning probe microscope described in the second aspect, it is possible to prevent the same particle from being observed in two adjacent scanning ranges in duplicate, and thus it is possible to accurately calculate the number of particles present in each observation field.

[0108] (Item 3) In the scanning probe microscope described in item 1, the sample is a sample containing powder. The data processing unit sets the interval of the scanning range to a predetermined value equal to or greater than the standard particle diameter of the powder. When the data processing unit receives user input of one of two variables, the scanning range and the maximum number of fields of view, it calculates the remaining one of the two variables based on the received one variable.

[0109] According to the scanning probe microscope described in paragraph 3, the input work of the user for setting a plurality of scanning ranges respectively corresponding to a plurality of image data can be simplified, thereby reducing the workload of the user. Furthermore, since it is possible to prevent the same particle from being observed in two adjacent scanning ranges in duplicate, it is possible to accurately calculate the number of particles present in each observation field.

[0110] (Item 4) In the scanning probe microscope described in any one of items 1 to 3, the data processing unit calculates the maximum number of fields of view as the number of scanning ranges that can be arranged at the aforementioned intervals from each other within the maximum scanning range, with the scanning range being arranged at the center of the maximum scanning range.

[0111] According to the scanning probe microscope described in paragraph 4, within the maximum scanning range, scanning ranges are arranged evenly in the X- and Y-axis directions with respect to the center of the maximum scanning range. This makes it possible to observe the observation target area evenly using a plurality of scanning ranges (observation fields of view).

[0112] (Item 5) In the scanning probe microscope described in any one of Items 1 to 4, the data processing unit is configured to set an acquisition order for the number of image data to be acquired when a user input is received for the number of acquisitions of the multiple image data based on the maximum number of fields of view. When the data processing unit receives a user input specifying the scanning range of the image data to be acquired first, it sets the acquisition order for the second and subsequent image data based on the position of the scanning range of the first image data.

[0113] According to the scanning probe microscope described in paragraph 5, the input work of the user for setting the acquisition order of multiple image data can be simplified, thereby reducing the workload of the user. Furthermore, when observing multiple samples, by specifying the scanning range of the image data to be acquired first, the acquisition order of the image data of the multiple samples can be unified. This allows the areas observed to be unified among the multiple samples.

[0114] (Item 6) In the scanning probe microscope described in Item 5, when setting the acquisition order of the second and subsequent image data, the data processing unit sets the acquisition order so that the horizontal movement distance of the scanner to acquire the number of image data is the shortest.

[0115] According to the scanning probe microscope described in item 6, it is possible to suppress deviation of the amount of movement of the scanner under open loop control from a target value, and therefore it is possible to reduce the influence of movement of the observation field of view.

[0116] (Item 7) A program according to one embodiment is a program for acquiring the observation image of an observation target area of ​​a sample using a computer having a data processing unit according to items 1 to 6.

[0117] According to the program described in paragraph 7, the input work of the user for setting multiple scanning ranges corresponding to multiple image data respectively can be simplified, thereby reducing the workload of the user.

[0118] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0119] 1 optical system, 2 cantilever, 3 probe, 4 holder, 5 beam splitter, 6 laser light source, 7 reflecting mirror, 8 photodetector, 10 observation device, 12 scanner, 12xy XY scanner, 12z Z scanner, 14 sample holder, 15 substrate, 16 XY direction drive unit, 18 Z direction drive unit, 20 information processing device, 22 feedback signal generator, 24 scanning signal generator, 26 data processing unit, 28 storage unit, 30 display device, 40 input device, 50, 52, 52A, 54, 56, 58, 60, 70, 72 tab, 100 scanning probe microscope, 160 CPU, 162 ROM, 164 RAM, 166 HDD, 168 communication I / F, 170 display I / F, 172 input I / F, R scanning range, Rmax maximum scanning range, D interval.

Claims

1. A probe disposed opposite to a surface of the sample; a scanner that moves a relative position between the sample and the probe; a driving unit configured to divide an observation target area of ​​the sample into a plurality of areas and drive the scanner to scan the surface of the sample for each area; a data processing unit that acquires a plurality of image data corresponding to the plurality of regions as an observation image of the observation target region; an input unit for receiving a user input regarding a condition for acquiring the plurality of image data; The data processing unit is configured to set the conditions based on a user input, the conditions including a scanning condition of the scanner; When the input means receives user input for any two of three variables, namely, the scanning range of the scanner for each image data, the interval between two adjacent scanning ranges, and the maximum number of fields of view obtainable from the maximum scanning range of the scanner, the data processing unit calculates the remaining one of the three variables based on the two received variables by executing an arithmetic process using the relationship between the three variables.

2. The sample is a sample containing a powder, 2. The scanning probe microscope according to claim 1, wherein the data processing unit sets a lower limit of a variable corresponding to the interval of the scanning range to a standard particle size of the powder.

3. The sample is a sample containing a powder, The data processing unit includes: The interval of the scanning range is set to a predetermined value equal to or larger than a standard particle diameter of the powder, 2. The scanning probe microscope according to claim 1, wherein, when a user input of one of two variables, the scanning range and the maximum number of fields of view, is accepted, the remaining one of the two variables is calculated based on the accepted one variable.

4. 4. The scanning probe microscope according to claim 1, wherein the data processing unit calculates, as the maximum number of fields of view, the number of scanning ranges that can be arranged at the intervals within the maximum scanning range with the scanning range arranged at the center of the maximum scanning range.

5. the data processing unit is configured to set an acquisition order of the number of the image data to be acquired when a user input is received for the number of the image data to be acquired based on the maximum number of fields of view; 5. The scanning probe microscope according to claim 1, wherein when the data processing unit receives a user input specifying a scanning range of the image data to be acquired first, it sets an acquisition order of the second and subsequent image data based on a position of the scanning range of the first image data.

6. 6. The scanning probe microscope according to claim 5, wherein when setting the acquisition order of the second and subsequent image data, the data processing unit sets the acquisition order so that a horizontal movement distance of the scanner for acquiring the number of pieces of image data is shortest.

7. 7. A program for acquiring the observation image of the observation target region of the sample, using a computer having the data processing unit according to claim 1.

Images