Scanning probe microscope, control device, control program, and control method

Abstract

This scanning probe microscope (100) for subjecting the surface of a sample (S) to analytical processing comprises: a cantilever (101); a detecting device (12) for detecting a physical characteristic of the cantilever (101); and a control device (11) for identifying the spring constant of the cantilever (101) on the basis of the physical characteristic detected by the detecting device (12). The control device (11) stores specific information (Tb1) for identifying the spring constant on the basis of the physical characteristic, acquires the physical characteristic detected by the detecting device (12), and identifies the spring constant on the basis of the acquired physical characteristic and the specific information (Tb1).

Description

Scanning probe microscope, control device, control program, and control method

[0001] The present disclosure relates to a scanning probe microscope, a control device, a control program, and a control method.

[0002] Scanning probe microscopes that use a probe to analyze the surface of a sample are known. Scanning probe microscopes calculate the force applied to the cantilever using the amount of curvature of the probe and the spring constant of the cantilever, and detect the surface shape of the sample by moving the cantilever along the surface of the sample so that the force applied to the cantilever is constant.

[0003] A user can manually input the spring constant of the cantilever into a scanning probe microscope. However, manually inputting the spring constant of the cantilever is a cumbersome task. In this regard, Patent Document 1 (Japanese Patent Laid-Open Publication No. 10-282128) discloses a scanning probe microscope that automatically calculates the spring constant of a cantilever based on the thermal fluctuation of the cantilever.

[0004] Japanese Patent Application Publication No. 10-282128

[0005] According to the scanning probe microscope described in Patent Document 1 (JP Patent Publication No. 10-282128), the spring constant of a cantilever can be calculated based on the thermal fluctuations of the cantilever. However, calculating the spring constant of a cantilever based on thermal fluctuations requires a dedicated hardware configuration. In general, there is a demand for a technology that can obtain the spring constant without a dedicated hardware configuration for using thermal fluctuations.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to identify the spring constant of a cantilever without the user having to manually input the spring constant of the cantilever.

[0007] A scanning probe microscope according to one aspect of the present disclosure is a scanning probe microscope that performs an analytical process on the surface of a sample. The scanning probe microscope includes a cantilever, a detection device that detects physical properties of the cantilever, and a control device that determines a spring constant of the cantilever based on the physical properties detected by the detection device. The control device stores determination information for determining the spring constant based on the physical properties, acquires the physical properties detected by the detection device, and determines the spring constant based on the acquired physical properties and determination information.

[0008] A control device according to one aspect of the present disclosure is a control device for controlling a scanning probe microscope that performs an analytical process on the surface of a sample using a cantilever. The control device includes a control unit that controls processes performed by the scanning probe microscope and a storage device. The control unit stores identification information for identifying a spring constant based on physical characteristics in the storage device, acquires the physical characteristics detected by a detection device that detects the physical characteristics of the cantilever, and identifies the spring constant based on the acquired physical characteristics and identification information.

[0009] A control program according to one aspect of the present disclosure is a control program used in a scanning probe microscope that performs an analytical process on the surface of a sample. The scanning probe microscope includes a cantilever, a detection device that detects physical properties of the cantilever, and a control device that determines a spring constant of the cantilever based on the physical properties detected by the detection device. The control program causes a computer to execute the steps of storing determination information for determining the spring constant based on the physical properties, acquiring the physical properties detected by the detection device, and determining the spring constant based on the acquired physical properties and determination information.

[0010] A control method according to one aspect of the present disclosure is a control method used in a scanning probe microscope that performs an analytical process on the surface of a sample. The scanning probe microscope includes a cantilever, a detection device that detects physical properties of the cantilever, and a control device that determines a spring constant of the cantilever based on the physical properties detected by the detection device. The control method includes, as processes executed by a computer, steps of storing determination information for determining the spring constant based on the physical properties, acquiring the physical properties detected by the detection device, and determining the spring constant based on the acquired physical properties and determination information.

[0011] According to the present disclosure, the spring constant of the cantilever can be determined by detecting the physical characteristics of the cantilever and using specific information for determining the spring constant of the cantilever based on the detected physical characteristics and pre-stored physical characteristics of the cantilever, thereby making it possible for the user to obtain the spring constant of the cantilever without manually inputting the spring constant of the cantilever.

[0012] FIG. 1 is a diagram showing a schematic configuration of a scanning probe microscope according to a first embodiment. FIG. 2 is a flowchart for explaining processing in an initial setting phase. FIG. 3 is a diagram showing an example of a table generated in step S110. FIG. 4 is a flowchart for explaining calculation of a spring constant in a sample analysis phase according to the first embodiment. FIG. 5 is a diagram for explaining angles set for each operation mode. FIG. 6 is a diagram showing an image that is an imaging result of an imaging device according to the first embodiment. FIG. 7 is a flowchart for explaining processing in a sample analysis phase according to a comparative example. FIG. 8 is a diagram showing a schematic configuration of a scanning probe microscope according to a second embodiment. FIG. 9 is a flowchart for explaining calculation of a spring constant in a sample analysis phase according to the second embodiment. FIG. 10 is a diagram showing an image that is an imaging result of an imaging device according to the second embodiment. FIG. 11 is a diagram showing a schematic configuration of a scanning probe microscope according to a third embodiment. FIG. 12 is a flowchart for explaining calculation of a spring constant in a sample analysis phase according to the third embodiment.

[0013] [First Embodiment] The present embodiment will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals, and in principle, descriptions thereof will not be repeated.

[0014] 1 is a diagram showing a schematic configuration of a scanning probe microscope (SPM) 100 according to embodiment 1. The scanning probe microscope 100 according to embodiment 1 is a microscope that performs an analytical process on the surface of a sample S, and is typically an atomic force microscope (AFM) that observes the shape of the surface of the sample S by utilizing the atomic force (attractive or repulsive force) acting between a probe (needle) 109 and the surface of the sample S.

[0015] In the following description, the installation surface of the scanning probe microscope 100 is defined as the XY plane, and the axis perpendicular to the XY plane is defined as the Z axis. In the following description, the positive side of the Z axis is referred to as "upper," and the negative side of the Z axis is referred to as "lower."

[0016] 1, a scanning probe microscope 100 includes a microscope main body 10, a control device 11, and a detection device 12. The microscope main body 10 includes a cantilever 101, a fixing device 102, a sample stage 103, a laser light source 104, a photodetector 105, a Z-direction actuator 106, and an XY-direction actuator 107.

[0017] The sample S is placed on a sample stage 103. A Z-direction actuator 106 that moves the sample stage 103 up and down (Z direction) is provided below the sample stage 103. An XY-direction actuator 107 that moves the sample stage 103 and the Z-direction actuator 106 in the X and Y directions is provided below the Z-direction actuator 106.

[0018] The Z-direction actuator 106 and the XY-direction actuator 107 have piezoelectric elements. The Z-direction actuator 106 and the XY-direction actuator 107 adjust the position of the sample stage 103 by applying voltages to the piezoelectric elements. In this way, the Z-direction actuator 106 and the XY-direction actuator 107 change the distance between the sample S and the tip 108 of the cantilever 101. The Z-direction actuator 106 and the XY-direction actuator 107 are also referred to as position adjustment devices.

[0019] The cantilever 101 is provided above the sample S. The probe 109 is provided at a tip 108, which is one end of the cantilever 101. The probe 109 is provided on the surface of the cantilever 101 so as to face the sample S. In other words, the surface of the cantilever 101 is the surface facing the sample S. The base material of the cantilever 101 is, for example, silicon.

[0020] The rear end 110 of the cantilever 101, which is the other end of the tip end 108, is connected to the fixing device 102. In other words, the cantilever 101 is a cantilever beam in which only the rear end 110 is fixed to the fixing device 102. The cantilever 101 is fixed to the fixing device 102 at a predetermined angle Ag1. As shown in FIG. 1 , the predetermined angle Ag1 is the angle formed between the in-plane direction of the main surface of the cantilever 101 and the X-axis direction.

[0021] The cantilever 101 is flexible. That is, the cantilever 101 is configured to bend when pressed against the sample S. The laser light source 104 and the photodetector 105 are provided above the cantilever 101. When measuring the sample S, the laser light source 104 irradiates laser light LA ​​toward the back surface of the tip 108 of the cantilever 101. The back surface of the cantilever 101 is the surface opposite to the surface facing the sample S.

[0022] The photoreceiver 105 is a sensor that detects the laser beam LA. The photoreceiver 105 is provided at a position where it can receive the laser beam LA reflected by the back surface of the cantilever 101. The photoreceiver 105 receives the laser beam LA reflected by the back surface of the tip 108 of the cantilever 101.

[0023] It should be noted that the position adjustment device that changes the distance between the sample S and the tip 108 of the cantilever 101 is not limited to the Z-direction actuator 106 and the XY-direction actuator 107, but may also be, for example, a movable fixing device 102.

[0024] The movable fixing device 102 has, for example, a rack-and-pinion mechanism and a motor inside the fixing device 102, and changes the position of the cantilever 101 by driving the motor. That is, the movable fixing device 102 fixes the sample S and adjusts the position of the rear end 110 of the cantilever 101. In addition, in the first embodiment, the position adjustment device that changes the distance between the sample S and the tip 108 of the cantilever 101 may be composed of both the Z-direction actuator 106 and the XY-direction actuator 107, and the movable fixing device 102.

[0025] The control device 11 is embodied by hardware such as a CPU (Central Processing Unit) and memory, and software that performs the arithmetic processing described below. The control device 11 controls the operation of the microscope main body 10. The control device 11 includes a processor 111, a memory 112, and a storage device 113. A display device and an input device, which are not shown in FIG. 1, are connected to the control device 11.

[0026] The processor 111 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or an MPU (Multi-Processing Unit). The processor 111 reads and executes programs stored in the memory 112 to realize the processing of the control device 11.

[0027] The memory 112 is realized by a volatile memory such as a RAM (Random Access Memory). The memory 112 is configured to be able to store programs executed by the processor 111, data used by the processor 111, etc. For example, the memory 112 stores various programs for operating the scanning probe microscope 100.

[0028] The storage device 113 is realized by a nonvolatile memory such as a read only memory (ROM) or a flash memory. In the example of the first embodiment, the storage device 113 stores specific information for specifying the spring constant of the cantilever 101 input by the user. The specific information is, for example, a table that stores the physical characteristics of the cantilever 101 for each type of cantilever 101. The specific information stores physical characteristics that allow the spring constant of the cantilever 101 to be calculated.

[0029] More specifically, the identification information includes information indicating the shape of the cantilever 101 and information indicating the material from which the cantilever 101 is made. The identification information will be described in detail below. The storage device 113 stores a control program Pr1, which is used by the scanning probe microscope 100 to perform an analytical process on the surface of the sample S and is used to identify the spring constant of the cantilever 101.

[0030] The control device 11 sends a control signal to an optical system driving device (not shown). The optical system driving device drives the laser light source 104 and the photodetector 105 in response to the control signal. As a result, the control device 11 controls the light emission and position of the laser light source 104, and controls the position of the photodetector 105. The photodetector 105 outputs detection information of the laser light LA ​​to the control device 11.

[0031] The control device 11 sends a control signal to an actuator driving device (not shown), and the actuator driving device applies voltages to the piezoelectric elements of the Z-direction actuator 106 and the XY-direction actuator 107 in response to the control signal. In this way, the control device 11 performs control to change the relative positional relationship between the cantilever 101 and the sample S.

[0032] Based on the detection information input from the photodetector 105, the control device 11 identifies the incident position of the laser light LA ​​detected by the photodetector 105, and based on that input position, calculates the Z-direction position of the tip 108 of the cantilever 101, i.e., the amount of warping of the probe 109 on the cantilever 101.

[0033] The detection device 12 detects the physical properties of the cantilever 101. In the first embodiment, the detection device 12 includes an imaging device 121. Specifically, the imaging device 121 is an optical microscope capable of capturing images of the cantilever 101 and the sample S from the positive side of the Z axis. The detection device 12 transmits the image of the imaging device 121 to the control device 11. In the first embodiment, the control device 11 calculates the shape of the cantilever from the image of the imaging device 121. Furthermore, the control device 11 can detect the relative positional relationship between the cantilever 101 and the sample S using the image of the imaging device 121.

[0034] As described above, in conventional scanning probe microscopes 100, the user may have to manually set the spring constant of the cantilever 101 each time an analysis of the sample S is performed or a new cantilever 101 is installed in the fixing device 102. However, since manually setting the spring constant by the user is a cumbersome task, it is desirable to be able to obtain the spring constant of the cantilever without the user having to manually input it. The control device 11 of this embodiment automatically determines the spring constant of the cantilever 101 based on the physical characteristics detected by the detection device 12.

[0035] The method for determining the spring constant will be described below, divided into an initial setup phase and a sample analysis phase. In the initial setup phase, a process is performed to store specific information for determining the spring constant in the storage device 113. In the sample analysis phase, a process is performed to determine the spring constant of the cantilever 101 attached to the fixing device 102 based on the specific information set in the initial setup phase and the detection results of the detection device 12.

[0036] [Initial Setup Phase] Fig. 2 is a flowchart for explaining the processing in the initial setup phase. The processing steps shown in Fig. 2 are realized by the control device 11 executing the control program Pr1. In the first embodiment, the control device 11 executes the flowchart of Fig. 2 based on receiving specific information indicating the physical characteristics of the cantilever 101 from the user.

[0037] The control device 11 generates a table showing the physical characteristics of the cantilever for each type of cantilever based on the input from the user (step S110). After generating the table, the control device 11 ends the process.

[0038] 3 is a diagram showing an example of the table Tb1 generated in step S110. The table Tb1 contains information such as "length (μm)", "width (μm)", "thickness (μm)", and "Young's modulus (N / μm)". ２ The table includes columns indicating the type of cantilever, such as the product name, model number, or product number. For example, information regarding the physical properties of a cantilever with the product name "Cantilever X" is published by the manufacturer of "Cantilever X." The user inputs the published information regarding the physical properties of "Cantilever X" into the control device 11. In this embodiment, the physical properties of the cantilever include the shape of the cantilever and the Young's modulus of the cantilever.

[0039] The manufacturer of "cantilever X" determines the physical properties of "cantilever X" as follows: "cantilever X" has a length of X 1 μm, a width of X 2 μm, a thickness of X 3 μm, and a Young's modulus of X 4 (N / μm) ２) in the initial setup phase. In the initial setup phase, the user inputs the physical properties published by the manufacturer of "cantilever X" into the control device 11. Similarly, the user inputs the physical properties published by the manufacturers of "cantilever Y" and "cantilever Z" into the control device 11. The control device 11 generates a table Tb1 showing the physical properties of each type of cantilever input by the user. Table Tb1 may correspond to the "specific information" in this disclosure. The manufacturer of "cantilever X" inputs the physical properties of length X1 μm, width X2 μm, thickness X3 μm, and Young's modulus X4 (N / μm ２ For example, if a manufacturer publishes information about the material of "cantilever X," the user may calculate the Young's modulus himself or herself based on the information about the material.

[0040] The control device 11 can identify the shape of the cantilever from its length, width, and thickness. The control device 11 can calculate the spring constant based on the identified shape of the cantilever and the Young's modulus, which is material information about the cantilever. In other words, if the control device 11 can identify the type of cantilever 101 installed in the fixing device 102, it can calculate the spring constant of the cantilever 101 based on the information stored in table Tb1. Table Tb1 is stored in the storage device 113.

[0041] [Sample Analysis Phase] Next, the sample analysis phase will be described. The sample analysis phase is executed after the initial setup phase. The sample analysis phase is executed each time a sample S is analyzed. FIG. 4 is a flowchart for explaining calculation of the spring constant in the sample analysis phase in the first embodiment. The processing steps shown in FIG. 4 are realized by the control device 11 executing the control program Pr1. In the first embodiment, the control device 11 executes the flowchart in FIG. 4 based on receiving an instruction to execute an analysis process from a user.

[0042] The control device 11 sets the operation mode based on input from the user (step S210). The scanning probe microscope 100 can operate in a plurality of predetermined operation modes. The operation modes input by the user include various modes such as contact mode and dynamic mode. The angle Ag1 at which the cantilever 101 is mounted to the fixing device 102 may differ depending on the operation mode. Note that in some aspects, the control device 11 may execute the subsequent steps S220 to S250 without acquiring the operation mode.

[0043] In the contact mode, the sample S placed on the sample stage 103 is brought closer to the probe 109. As a result, the probe 109 comes into contact with the surface of the sample S, causing the probe 109 to warp. In the contact mode, the sample S is moved in a plane perpendicular to the surface while adjusting the distance between the probe 109 and the sample S so as to keep the amount of warping constant, thereby scanning the surface and obtaining two-dimensional information about the shape of the surface.

[0044] In the dynamic mode, the cantilever 101 is vibrated at its resonant frequency, and the sample S placed on the sample stage 103 is brought closer to the probe 109 at the tip of the cantilever 101. In the dynamic mode, the surface is scanned by moving the sample in a plane perpendicular to the sample S while adjusting the distance between the probe 109 and the sample S so as to keep the amplitude of the vibration of the cantilever 101 constant, thereby obtaining two-dimensional information about the surface shape.

[0045] 5 is a diagram for explaining the angle Ag1 set for each operation mode. As described above, in the scanning probe microscope 100, the angle Ag1 at which the cantilever 101 shown in FIG. 1 is mounted on the fixing device 102 varies depending on the operation mode.

[0046] 5 , when the scanning probe microscope 100 operates in the first mode, the cantilever 101 is mounted to the fixing device 102 at an angle A1. When the scanning probe microscope 100 operates in the second mode, the cantilever 101 is mounted to the fixing device 102 at an angle A2. When the scanning probe microscope 100 operates in the third mode, the cantilever 101 is mounted to the fixing device 102 at an angle A3. Therefore, in table Tb2, angle A1 is associated with the first mode, angle A2 is associated with the second mode, and angle A3 is associated with the third mode. Table Tb2 is stored in the storage device 113.

[0047] 4, in step S210, the control device 11 reads out the angle Ag1 corresponding to the operation mode received from the user, and then acquires the width W1 and length L1B of the cantilever 101 based on the image P1 captured by the imaging device 121 (step S220).

[0048] 6 is a diagram showing image P1, which is the imaging result of the imaging device 121 in embodiment 1. As described above, the imaging device 121 in embodiment 1 images the cantilever 101 from the positive side of the Z axis. In other words, the imaging device 121 images the cantilever 101 from the normal direction of the sample stage 103. Image P1 shows the shape of the cantilever.

[0049] As shown in Fig. 6, cantilever 101 has a main surface Sf1 when viewed from the positive side of the Z axis. Cantilever 101 has a flat plate shape with a longitudinal direction LD oriented in the X axis direction. As shown in Fig. 6, when viewed from the positive side of the Z axis, tip 108 of cantilever 101 has a protruding shape.

[0050] 6 shows the width W1 of the cantilever 101 in the short-side direction SD. Also shown in FIG. 6 is the length L1B of the cantilever 101 in the longitudinal direction LD in image P1. The in-plane direction of the main surface of the cantilever 101 is tilted at an angle Ag1 from the X-Y plane. The angle Ag1 indicates that the in-plane direction of the main surface of the cantilever 101 and the imaging direction of the imaging device 121 are not perpendicular to each other. Therefore, the length L1B shown in image P1 is shorter than the actual length L1 of the main surface Sf1 of the cantilever 101.

[0051] 4, the control device 11 acquires the width W1 and the length L1B based on the image P1. Then, the control device 11 corrects the length L1B to calculate the actual length of the cantilever 101 in the longitudinal direction LD (step S230). The control device 11 acquires the actual length L1 of the cantilever 101 in the longitudinal direction LD using the uncorrected length L1B acquired in step S220 and the angle Ag1 acquired in step S210. The control device 11 calculates the length of the cantilever 101 in the longitudinal direction LD based on the angle formed between the imaging direction (Z-axis direction) of the detection device 12 and the in-plane direction of the main surface of the cantilever 101.

[0052] The control device 11 refers to the table Tb1 based on the width W1 and the length L1 to identify the type of the cantilever 101 (step S240). Specifically, the control device 11 identifies the type of cantilever 101 whose width W1 acquired in step S220 and whose length L1 acquired in step S230 are closest to each other. This allows the control device 11 to identify the type of the cantilever 101 fixed to the fixing device 102 based on the physical characteristics of the cantilever 101, namely, the width W1 and the length L1.

[0053] For example, the control device 11 identifies the type of cantilever 101 as "cantilever Y." In this case, the control device 11 can identify that the thickness of the cantilever 101 fixed to the fixing device 102 is Y3 and the Young's modulus is Y4. The control device 11 calculates the spring constant of the cantilever 101 using the width W1 acquired in step S220, the length L1 acquired in step S230, and the thickness Y3 and Young's modulus Y4 stored in table Tb1 (step S250). The control device 11 calculates the size of the flat shape of the cantilever 101 using the width W1 and length L1 obtained by actual measurement and the thickness Y3, which is a value published by the manufacturer. If the control device 11 can acquire the size of the flat shape of the cantilever 101 and the Young's modulus Y4 of the cantilever 101, it can calculate the spring constant of the cantilever 101 based on this information.

[0054] In this way, in step S250, the control device 11 determines the spring constant of the cantilever 101 based on the physical characteristics of the cantilever 101 and table Tb1. After executing step S250, the control device 11 ends the flowchart for calculating the spring constant in the sample analysis phase. The control device 11 performs an analysis process on the surface of the sample S using the spring constant calculated in FIG. 4.

[0055] 7 is a flowchart for explaining the processing of the sample analysis phase in the comparative example. In the comparative example, as in the first embodiment, the control device 11 sets the operation mode based on input from the user (step S210). Next, in the comparative example, the spring constant of the cantilever 101 input by the user is accepted (step S220Z). That is, in the comparative example, the user is required to input the spring constant of the cantilever 101 into the control device 11 each time a sample is analyzed in the sample analysis phase, which increases the user's workload in the analysis process.

[0056] On the other hand, in the scanning probe microscope 100 of this embodiment, the spring constant can be calculated automatically based on the physical characteristics of the cantilever 101 detected by the detection device 12, without the user having to manually input the spring constant. Furthermore, in the first embodiment, the width W1 and length L1 obtained in steps S220 and S230 are actual measurements of the cantilever 101 actually mounted on the fixing device 102.

[0057] As a result, even if the width W1 and length L1 of the cantilever 101 attached to the fixing device 102 deviate from the width and length values ​​published by the manufacturer, the shape of the cantilever 101 can be calculated with high accuracy using the actual measured values. That is, in the first embodiment, by using the actually measured physical characteristics of the cantilever 101, the accuracy of the calculated spring constant is improved compared to when the spring constant is calculated using only the information of the manufacturer's published values. In this way, with the scanning probe microscope 100 of the first embodiment, the spring constant of the cantilever 101 can be obtained with high accuracy without the user having to manually input the spring constant.

[0058] In the first embodiment, the control device 11 identifies the type of cantilever based on the measured width W1 and length L1. However, the physical property of the cantilever 101 that is measured may be only one of the width W1 and the length L1. In this case, the control device 11 identifies the type of cantilever based on only one of the measured width W1 and the length L1. That is, when the control device 11 measures only the width W1, it identifies the type of cantilever 101 installed in the fixing device 102 as the type of cantilever having the width closest to the measured width W1 in the table Tb1.

[0059] [Embodiment 2] In the first embodiment, a configuration has been described in which the type of cantilever 101 is identified based on the measured width W1 and length L1. In the second embodiment, a configuration will be described in which the detection device 12 measures the thickness of the cantilever 101 in addition to the width W1 and length L1. The thickness of the cantilever 101 is the length of the cantilever 101 in the normal direction to the main surface Sf1 of the cantilever 101.

[0060] 8 is a diagram showing a schematic configuration of a scanning probe microscope 100A according to embodiment 2. Note that in embodiment 2, description of the configuration that overlaps with scanning probe microscope 100 according to embodiment 1 will not be repeated.

[0061] 8 , in the scanning probe microscope 100A of the second embodiment, the detection device 12 has an imaging device 122 in addition to the imaging device 121. The imaging device 122 is an optical microscope that can image the cantilever 101 from a direction different from that of the imaging device 121. More specifically, the imaging device 122 images the cantilever 101 from the positive side of the Y axis. In the second embodiment, the thickness of the cantilever 101 is measured by imaging the cantilever 101 from the positive side of the Y axis.

[0062] Fig. 9 is a flowchart for explaining calculation of the spring constant in the sample analysis phase in embodiment 2. The processing steps shown in Fig. 9 are realized by execution of control program Pr1 by control device 11. In embodiment 2 as well, control device 11 executes the flowchart in Fig. 9 based on receipt of an execution command for analysis processing from the user.

[0063] Steps S310 and S320 in Fig. 9 are the same processes as steps S210 and S220 in Fig. 4. The control device 11 acquires the width W1 and the length L1B based on the image P1 acquired by the imaging device 121, and then acquires the thickness T1 and the angle Ag1 using the image P2 acquired by the imaging device 122 (step S330).

[0064] Fig. 10 is a diagram showing image P2, which is the result of imaging by the imaging device 122 in embodiment 2. As described above, in embodiment 2, the imaging device 122 images the cantilever 101 from the positive side of the Y axis. As shown in Fig. 10, image P2 shows the cantilever 101 and the fixing device 102 as viewed from the positive side of the Y axis. Image P2 also shows the shape of the cantilever.

[0065] As shown in Fig. 10, the cantilever 101 has a side surface Sf2 when viewed from the positive side of the Y axis. As shown in Fig. 6, the image P2 shows the thickness T1 of the cantilever 101. The image P2 also shows the angle Ag1.

[0066] 9 , in step S330, the control device 11 acquires the thickness T1 and the angle Ag1 based on the image P2. Thereafter, the control device 11 calculates the longitudinal length L1 of the cantilever 101 using the length L1B acquired in step S320 and the angle Ag1 acquired in step S330 (step S340). The control device 11 identifies the type of the cantilever 101 by referring to table Tb1 using the measured thickness T1, width W1, and length L1 (step S350).

[0067] In the second embodiment, the control device 11 identifies, for example, the type of the cantilever 101 as "cantilever Z." In this case, the control device 11 can identify that the Young's modulus of the cantilever 101 fixed to the fixing device 102 is Z4. The control device 11 calculates the spring constant of the cantilever 101 using the width W1 acquired in step S320, the thickness T1 acquired in step S330, the length L1 acquired in step S340, and the Young's modulus Z4 (N / μm2) stored in table Tb1 (step S360).

[0068] In this way, in step S360, the control device 11 determines the spring constant of the cantilever 101 based on the physical characteristics of the cantilever 101 and table Tb1. In the second embodiment, similar to the first embodiment, the spring constant can be calculated based on the physical characteristics of the cantilever 101 without the user having to manually input the spring constant.

[0069] In the second embodiment, the control device 11 actually measures the thickness T1 in addition to the width W1 and length L1. Therefore, in the second embodiment, the type of cantilever can be identified more accurately than in the first embodiment. Furthermore, in the second embodiment, even if the width W1, length L1, and thickness T1 of the cantilever 101 attached to the fixing device 102 deviate from the manufacturer's published values, the shape of the cantilever 101 can be calculated with high accuracy using the actual measured values ​​of the width W1, length L1, and thickness T1. In this way, the scanning probe microscope 100A of the second embodiment also allows the spring constant of the cantilever 101 to be obtained with high accuracy without the user having to manually input the spring constant.

[0070] In the example of the second embodiment described above, the length L1 is obtained using the actually measured angle Ag1. However, if the control device 11 can obtain the length L1 directly from the image P2, the control device 11 does not need to obtain the angle Ag1. In other words, the control device 11 may directly obtain the length L1 shown in the image P2.

[0071] Furthermore, in the second embodiment, an example has been described in which the scanning probe microscope 100A includes the imaging device 122 in addition to the imaging device 121. However, the scanning probe microscope 100A may include only the imaging device 122 without including the imaging device 121. That is, in this embodiment, it is sufficient that the type of the cantilever 101 can be identified using table Tb1, and the number of physical properties of the cantilever 101 detected to identify the type of the cantilever 101 is not limited to one to three, and may be four or more. Note that the more physical properties of the cantilever 101 that are detected, the more accurately the type of the cantilever 101 can be identified and the calculation of the spring constant is less susceptible to tolerances, so it is desirable to detect as many physical properties of the cantilever 101 as possible.

[0072] Third Embodiment In the first and second embodiments, the configuration for identifying the type of cantilever 101 based on the shape of cantilever 101 has been described. In the third embodiment, the configuration for acquiring the Young's modulus of cantilever 101 using detection device 12 will be described.

[0073] 11 is a diagram showing a schematic configuration of a scanning probe microscope 100B according to embodiment 3. Note that in embodiment 3, description of configurations that overlap with scanning probe microscopes 100 and 100A according to embodiments 1 and 2 will not be repeated.

[0074] 11 , in the scanning probe microscope 100B of the third embodiment, the detection device 12 has a light source 123T and a light receiver 123R in addition to the imaging device 121. The light source 123T irradiates light toward the cantilever 101. As described above, the base material of the cantilever 101 is silicon. The light irradiated by the light source 123T has a wavelength that can be transmitted through the base material of the cantilever 101, such as infrared light.

[0075] The light receiver 123R receives the transmitted light that is irradiated by the light source 123T and has passed through the cantilever 101. In the third embodiment, the control device 11 calculates the Young's modulus of the cantilever 101 based on the intensity of the transmitted light received by the light receiver 123R. The control device 11 of the third embodiment identifies the type of the cantilever using the Young's modulus calculated by the light source 123T and the light receiver 123R.

[0076] Furthermore, the control device 11 of the third embodiment is connected to a network NW. The network NW is typically the Internet. In the third embodiment, the control device 11 updates table Tb1 and adds data to table Tb1 via the network NW. More specifically, the control device 11 connects to a server owned by, for example, a cantilever manufacturer, and acquires and updates the physical characteristics of each type of cantilever. As a result, in the third embodiment, the user does not need to perform the initial setup phase, reducing the user's workload and enabling the data stored in table Tb1 to be kept up to date.

[0077] Fig. 12 is a flowchart for explaining calculation of the spring constant in the sample analysis phase in embodiment 3. The processing steps shown in Fig. 12 are realized by execution of control program Pr1 by control device 11. In embodiment 3 as well, control device 11 executes the flowchart of Fig. 12 based on receipt of an execution command for analysis processing from the user.

[0078] Steps S410 to S430 in Fig. 12 are the same as steps S210 to S230 in Fig. 4. After step S430, the control device 11 of the third embodiment acquires information about the material of the cantilever based on the transmitted light received by the light receiver 123R, and acquires the Young's modulus based on the information about the material (step S440). Thereafter, the control device 11 identifies the type of cantilever 101 by referring to table Tb1 using the measured Young's modulus, width W1, and length L1 (step S450), and calculates the spring constant of the cantilever 101 (step S460).

[0079] In the third embodiment, the control device 11 acquires the Young's modulus based on information about the width W1 and length L1 as well as information about the material of the cantilever 101 that has been measured. Therefore, in the third embodiment, the type of cantilever can be identified more accurately than in the first embodiment. Furthermore, in the third embodiment, even if the width W1, length L1, and Young's modulus of the cantilever 101 attached to the fixing device 102 deviate from the manufacturer's published values, the shape of the cantilever 101 can be calculated with high accuracy using the measured values ​​of the width W1, length L1, and Young's modulus. In this way, the scanning probe microscope 100B of the third embodiment also allows the spring constant of the cantilever 101 to be acquired with high accuracy without the user having to manually input the spring constant.

[0080] In the third embodiment, the control device 11 identifies the type of cantilever based on the measured width W1, length L1, and Young's modulus. However, the physical property of the cantilever 101 to be measured may be only one of the width W1, length L1, and Young's modulus. For example, the detection device 12 may not include the imaging device 121, but may include only the light source 123T and the light receiver 123R, and the control device 11 may acquire only the Young's modulus and identify the type of cantilever based on the acquired Young's modulus.

[0081] [Modification] In the first embodiment, the control device 11 calculates the spring constant by using the measured width W1 and length L1 and the manufacturer's published values ​​of thickness and Young's modulus stored in table Tb1 after identifying the type of cantilever 101. However, after identifying the type of cantilever 101, the control device 11 may calculate the spring constant by using the manufacturer's published values ​​of width, length, thickness, and Young's modulus stored in table Tb1 without using the measured data. In other words, the measured values ​​may be used only to identify the type of cantilever, and in this case, the control device 11 may calculate the spring constant from the manufacturer's published values.

[0082] In the above example, the control device 11 determines the shape of the cantilever by taking into consideration the length, width, and thickness of the cantilever 101. However, the control device 11 may determine the shape of the cantilever by taking into consideration, for example, the protrusion shape of the tip portion 108 in addition to the length, width, and thickness.

[0083] In the first embodiment, the control device 11 has been described as having an arithmetic processing unit such as a CPU or an MPU. However, the control device 11 may be configured according to a hardware circuit dedicated to the scanning probe microscope 100. Furthermore, although the example in Fig. 1 illustrates a configuration in which there is a single processor, the control device 11 may have multiple processors.

[0084] The processor 111 is a computing entity (computer) that executes various processes according to various programs. The processor 111 may be configured, for example, with at least one of a central processing unit (CPU), a graphics processing unit (GPU), and a multi-processing unit (MPU). The processor 111 has the function of executing various processes by executing programs, but some or all of these functions may be implemented by application-specific integrated circuits such as field programmable gate arrays (FPGAs) and application-specific integrated circuits (ASICs). The processor 111 may also be configured with processing circuitry.

[0085] In this disclosure, the term "processor" is not limited to a processor in the narrow sense that executes processing using a stored program, such as a CPU or MPU, but may also include hardwired circuits such as an ASIC or FPGA. Therefore, the processor 111 may also be interpreted as a processing circuitry whose processing is predefined by computer-readable code and / or hardwired circuits.

[0086] The processor 111 may be configured as a single chip or multiple chips. Furthermore, the processor 111 and related processing circuits may be configured as multiple computers interconnected by wire or wirelessly via a local area network or a wireless network. The processor 111 and related processing circuits may be configured as a cloud computer that performs calculations remotely based on input data and outputs the calculation results to another device in a remote location.

[0087] Furthermore, in the above example, the storage device 113 is described as being a ROM. However, the storage device 113 may be in any format that can be read by the control device 11, which is a type of computer, and that can non-temporarily record a program. For example, the storage device 113 may be any of a CD-ROM (Compact Disc - Read Only Memory), a DVD-ROM (Digital Versatile Disk - Read Only Memory), a USB (Universal Serial Bus) memory, a memory card, a FD (Flexible Disk), a hard disk, an SSD (Solid State Drive), a magnetic tape, a cassette tape, an MO (Magnetic Optical Disc), an MD (Mini Disc), an IC (Integrated Circuit) card (excluding memory cards), an optical card, a mask ROM, and an EPROM.

[0088] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0089] (Item 1) A scanning probe microscope 100 for analyzing a sample according to one aspect is a scanning probe microscope that performs an analytical process on the surface of a sample S. The scanning probe microscope 100 includes a cantilever 101, a detection device 12 that detects physical properties of the cantilever 101, and a control device 11 that identifies the spring constant of the cantilever based on the physical properties detected by the detection device 12. The control device 11 stores identification information (table Tb1) for identifying the spring constant based on the physical properties (step S110), acquires the physical properties detected by the detection device 12 (step S220), and identifies the spring constant based on the acquired physical properties and identification information (S250).

[0090] According to the scanning probe microscope 100 described in paragraph 1, the user can specify the spring constant of the cantilever 101 without manually inputting the spring constant of the cantilever 101 .

[0091] (Item 2) In the scanning probe microscope 100 described in item 1, the detection device 12 captures an image of the shape of the cantilever 101, and the physical characteristics include the shape of the cantilever 101 shown in images P1 and P2 obtained by the image capture by the detection device 12. The control device 11 acquires information indicating the length of the cantilever 101 based on the shape of the cantilever 101 shown in images P1 and P2 (steps S220 and S230), and identifies the spring constant based on the information indicating the length of the cantilever 101 and the identification information (step S250).

[0092] According to the scanning probe microscope 100 described in the second paragraph, the spring constant of the cantilever can be determined based on the image obtained by imaging with the detection device.

[0093] (Item 3) In the scanning probe microscope 100 described in item 1 or 2, the information indicating the length of the cantilever 101 includes the length (width W1) of the main surface Sf1 of the cantilever 101 in the short-side direction SD.

[0094] According to the scanning probe microscope 100 described in paragraph 3, the type of cantilever can be identified using the width W1 of the cantilever 101, and the spring constant can be calculated.

[0095] (4) In the scanning probe microscope 100 described in any one of paragraphs 1 to 3, the information indicating the length of the cantilever 101 includes the length L1 of the main surface Sf1 of the cantilever 101 in the longitudinal direction LD.

[0096] According to the scanning probe microscope 100 described in item 4, the type of the cantilever 101 can be identified using the length L1 of the cantilever 101, and the spring constant can be calculated.

[0097] (5) In the scanning probe microscope 100 described in 4, the control device 11 calculates the length L1 of the cantilever 101 in the longitudinal direction LD based on the angle between the imaging direction (Z-axis direction) of the detection device 12 and the in-plane direction of the main surface Sf1 of the cantilever 101 (S230).

[0098] According to the scanning probe microscope 100 described in Section 5, the length L1B shown in the image P1 can be corrected to the actual length L1 of the cantilever 101 using the angle Ag1.

[0099] (Item 6) In the scanning probe microscope 100A described in any one of Items 1 to 5, the information indicating the length of the cantilever 101 includes the thickness of the cantilever 101 in the normal direction (Z-axis direction) of the main surface Sf1.

[0100] According to the scanning probe microscope 100A described in item 6, the type of the cantilever 101 can be identified using the thickness T1 of the cantilever 101, and the spring constant can be calculated.

[0101] (Item 7) In the scanning probe microscope 100B described in any one of Items 1 to 6, the detection device 12 (123T, 123R) detects transmitted light that has passed through the cantilever 101, and the physical properties include the Young's modulus of the cantilever 101. The control device 11 acquires information indicating the Young's modulus based on the transmitted light (step S440), and identifies the spring constant based on the information indicating the Young's modulus and the identification information (step S460).

[0102] According to the scanning probe microscope 100B described in item 7, the type of the cantilever 101 can be identified using the Young's modulus of the cantilever 101, and the spring constant can be calculated.

[0103] (Item 8) In the scanning probe microscope 100 described in any one of Items 1 to 7, the specific information (table Tb1) is information for calculating the spring constant from the length L1 of the cantilever 101 in the longitudinal direction LD, the length (width W1) in the lateral direction SD, the thickness T1 of the cantilever, and Young's modulus.

[0104] According to the scanning probe microscope 100 described in paragraph 8, the spring constant can be calculated based on the length L1 of the cantilever 101 in the longitudinal direction LD, the length (width W1) in the lateral direction SD, the thickness T1 of the cantilever, and Young's modulus.

[0105] (Item 9) In the scanning probe microscope 100B according to any one of Items 1 to 8, the control device 11 updates the specific information via the network NW.

[0106] According to the scanning probe microscope 100B described in paragraph 9, the user does not need to perform the initial setup phase, which reduces the workload on the user and allows the data stored in table Tb1 to be kept up to date.

[0107] (Item 10) A control device according to one aspect is a control device 11 that controls a scanning probe microscope 100 that performs an analytical process on the surface of a sample S using a cantilever 101. The control device includes a control unit (processor 111) that controls the processes executed by the scanning probe microscope 100, and a storage device 113. The control unit (processor 111) stores, in the storage device 113, specification information (table Tb1) for specifying the spring constant of the cantilever 101 based on the physical characteristics of the cantilever 101, acquires the physical characteristics detected by a detection device 12 that detects the physical characteristics of the cantilever (step S220), and specifies the spring constant based on the acquired physical characteristics and specification information (step S250).

[0108] According to the control device 11 described in paragraph 10, the spring constant of the cantilever 101 can be specified without the user having to manually input the spring constant of the cantilever 101 .

[0109] (Item 11) A control program Pr1 according to one aspect is a control program used in a scanning probe microscope 100 that performs an analytical process on the surface of a sample S. The scanning probe microscope 100 includes a cantilever 101, a detection device 12 that detects physical properties of the cantilever 101, and a control device 11 that identifies the spring constant of the cantilever 101 based on the physical properties detected by the detection device 12. The control program causes a computer to execute the following steps: storing identification information (table Tb1) for identifying the spring constant based on the physical properties (step S110); acquiring the physical properties detected by the detection device 12 (step S220); and identifying the spring constant based on the acquired physical properties and identification information (step S250).

[0110] According to the control program described in paragraph 11, the spring constant of the cantilever 101 can be specified without the user having to manually input the spring constant of the cantilever 101 .

[0111] (Item 12) A control method according to one aspect is a control method used in a scanning probe microscope 100 that performs an analytical process on the surface of a sample S. The scanning probe microscope 100 includes a cantilever 101, a detection device 12 that detects physical properties of the cantilever, and a control device 11 that identifies a spring constant of the cantilever 101 based on the physical properties detected by the detection device 12. The control method includes, as processes executed by a computer, a step of storing identification information (table Tb1) for identifying the spring constant based on the physical properties (step S110), a step of acquiring the physical properties detected by the detection device 12 (step S220), and a step of identifying the spring constant based on the acquired physical properties and identification information (step S250).

[0112] According to the control method described in paragraph 12, the user can specify the spring constant of the cantilever 101 without manually inputting the spring constant of the cantilever 101 .

[0113] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0114] 10 microscope main body, 11 control device, 12 detection device, 100, 100A, 100B scanning probe microscope, 101 cantilever, 102 fixing device, 103 sample stage, 104 laser light source, 105, 123R photodetector, 106, 107 directional actuator, 108 tip portion, 109 probe, 110 rear end portion, 111 processor, 112 memory, 113 storage device, 121, 122 imaging device, 123T light source, Ag1 angle L1B, L1 length, LA laser light, LD longitudinal direction, NW network, P1, P2 image, Pr1 control program, S sample, SD short direction, Sf1 main surface, Sf2 side, T1 thickness, Tb1, Tb2 table, W1 width.

Claims

1. A scanning probe microscope for performing analytical processing on the surface of a sample, comprising: a cantilever; a detection device for detecting physical characteristics of the cantilever; and a control device for identifying a spring constant of the cantilever based on the physical characteristics detected by the detection device, wherein the control device stores identification information for identifying the spring constant based on the physical characteristics, acquires the physical characteristics detected by the detection device, and identifies the spring constant based on the acquired physical characteristics and the identification information.

2. A scanning probe microscope as described in claim 1, wherein the detection device images the shape of the cantilever, the physical characteristics include the shape of the cantilever shown in an image obtained by imaging with the detection device, and the control device obtains information indicating the length of the cantilever based on the shape of the cantilever shown in the image, and identifies the spring constant based on the information indicating the length of the cantilever and the identification information.

3. A scanning probe microscope according to claim 1, wherein the information indicating the length of the cantilever includes the length of the main surface of the cantilever in the short direction.

4. A scanning probe microscope according to claim 1, wherein the information indicating the length of the cantilever includes a length of a main surface of the cantilever in the longitudinal direction.

5. A scanning probe microscope as described in claim 4, wherein the control device calculates the longitudinal length of the cantilever based on the angle between the imaging direction of the detection device and the in-plane direction of the main surface of the cantilever.

6. A scanning probe microscope according to claim 1, wherein the information indicating the length of the cantilever includes a thickness of the cantilever in a normal direction to a main surface of the cantilever.

7. A scanning probe microscope as described in claim 1, wherein the detection device detects transmitted light that has passed through the cantilever, the physical characteristics include Young's modulus of the cantilever, and the control device obtains information indicating the Young's modulus based on the transmitted light, and identifies the spring constant based on the information indicating the Young's modulus and the identification information.

8. A scanning probe microscope according to claim 1, wherein the specific information is information for calculating the spring constant from the longitudinal length, lateral length, thickness and Young's modulus of the cantilever.

9. The scanning probe microscope according to claim 1, wherein the control device updates the specific information via a network.

10. A control device for controlling a scanning probe microscope that performs analytical processing on the surface of a sample using a cantilever, comprising: a control unit that controls processing executed by the scanning probe microscope; and a memory device, wherein the control unit stores specific information for identifying a spring constant of the cantilever based on physical characteristics of the cantilever in the memory device, acquires the physical characteristics detected by a detection device that detects the physical characteristics of the cantilever, and identifies the spring constant based on the acquired physical characteristics and the specific information.

11. A control program used in a scanning probe microscope that performs analytical processing on the surface of a sample, the scanning probe microscope comprising: a cantilever, a detection device that detects physical characteristics of the cantilever, and a control device that identifies a spring constant of the cantilever based on the physical characteristics detected by the detection device, the control program causing a computer to execute the steps of: storing identification information for identifying the spring constant based on the physical characteristics; acquiring the physical characteristics detected by the detection device; and identifying the spring constant based on the acquired physical characteristics and the identification information.

12. A control method used in a scanning probe microscope that performs analytical processing on the surface of a sample, the scanning probe microscope comprising: a cantilever; a detection device that detects physical characteristics of the cantilever; and a control device that identifies a spring constant of the cantilever based on the physical characteristics detected by the detection device, the control method including, as processing executed by a computer, a step of storing identification information for identifying the spring constant based on the physical characteristics; a step of acquiring the physical characteristics detected by the detection device; and a step of identifying the spring constant based on the acquired physical characteristics and the identification information.

Images