Scanning probe microscope and method

Abstract

A scanning probe microscope (1) comprises: a cantilever (10); a detector (28) which detects laser light (LA) incident upon a light-receiving surface (280); a drive device (40) which causes the detector (28) to move; and a control device (100). The control device (100) controls the drive device (40) during an approach period in which a probe (12) is made to approach a sample (S), thereby adjusting the position of the detector (28) such that the laser light (LA) reflected off of the cantilever (10) is incident upon the light-receiving surface (280).

Description

Scanning probe microscope and method

[0001] The present invention relates to scanning probe microscopes and methods.

[0002] A scanning probe microscope includes a cantilever having a probe, a laser light source that irradiates the cantilever with laser light, and a detector that detects the laser light. In a scanning probe microscope, it is necessary to adjust the position of the detector so that the light reflected from the cantilever is incident on the detector. In conventional scanning probe microscopes, the position of the detector is adjusted before measuring the sample (see, for example, Patent Document 1 (Japanese Patent No. 7318471), Patent Document 2 (Japanese Patent No. 7255521), and Patent Document 3 (Japanese Patent Laid-Open No. 2007-78577)).

[0003] Japanese Patent No. 7318471 Japanese Patent No. 7255521 Japanese Patent Laid-Open No. 2007-78577

[0004] After the position of the detector is adjusted, the scanning probe microscope measures the sample after an approach period. During the approach period, for example, the probe and sample are brought close together so that the sample can be measured with the probe. During the approach period, the scanning probe microscope sets the probe to an appropriate position relative to the sample and then begins measuring the sample. The scanning probe microscope measures the sample by using a detector to detect the amount of change in the incident position of the laser light in response to changes in the deflection or vibration of the cantilever.

[0005] During the approach period, the cantilever may gradually bend due to the effects of electrostatic force, laser heat, and the like. As the cantilever bends more, the position of the laser light incident on the detector gradually shifts in the direction of the cantilever's bending. This may cause the detector position, which was adjusted before the sample measurement, to become inappropriate for the measurement during the approach period before the sample measurement.

[0006] The present invention has been made to solve such problems, and its object is to maintain a detector that detects laser light at an appropriate position during the approach period.

[0007] A scanning probe microscope according to one aspect of the present invention includes a cantilever having a probe, a laser light source for irradiating laser light onto the cantilever, a detector including a light-receiving surface and detecting the laser light incident on the light-receiving surface, a drive device for moving the detector along a plane intersecting the optical axis of the laser light incident on the light-receiving surface, and a control device, wherein the control device controls the drive device during an approach period in which the probe is brought close to a sample, thereby adjusting the position of the detector so that the laser light reflected by the cantilever is incident on the light-receiving surface.

[0008] A method according to another aspect of the present invention is a method for causing a probe of a cantilever provided in a scanning probe microscope apparatus to approach a sample, the scanning probe microscope apparatus comprising: a laser that directs laser light onto the cantilever; a detector that includes a light-receiving surface and detects the laser light that has entered the light-receiving surface; and a drive device that moves the detector along a plane that intersects with the optical axis of the laser light that has entered the light-receiving surface, the method causing a computer to execute the steps of causing the probe to approach the sample; and controlling the drive device during an approach period in which the probe is approached to the sample, thereby adjusting the position of the detector so that the laser light reflected by the cantilever irradiates the light-receiving surface.

[0009] According to the present invention, the detector that detects the laser light can be maintained at an appropriate position during the approach period.

[0010] It is a figure which shows typically the structure of the scanning probe microscope which concerns on embodiment. It is a figure for explaining the outline of the method of adjusting the position of the detector in the approach period. It is a flowchart which shows the procedure of the process which is executed by the control device. It is a flowchart which shows the details of the subroutine shown in FIG. It is a flowchart which shows the procedure of the subroutine which concerns on the modified example.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the following description, the same or corresponding parts in the drawings are denoted by the same reference numerals, and their description will not be repeated in principle.

[0012] 1 is a diagram schematically showing the configuration of a scanning probe microscope 1 according to an embodiment. In the following description, the contact surface of the scanning probe microscope 1 is defined as the XY plane, and the axis perpendicular to the XY plane is defined as the Z axis.

[0013] The scanning probe microscope 1 comprises a cantilever 10 , a holder 14 , an optical system 20 , driving devices 30 and 40 , a scanner 50 , a sample holder 52 , a camera 60 , and a control device 100 .

[0014] The cantilever 10 is provided so as to be positioned above the sample S placed on the sample holder 52. The cantilever 10 is supported by a holder 14 so as to be able to vibrate in the up and down direction. The cantilever 10 has a probe 12.

[0015] The optical system 20 irradiates the back surface of the cantilever 10 with laser light LA ​​and detects the laser light LA ​​reflected by the back surface of the cantilever 10. The control device 100 calculates the amount of deflection of the cantilever 10 based on the laser light LA ​​detected by the optical system 20. The optical system 20 includes a laser light source 22, a beam splitter 24, a reflecting mirror 26, and a detector 28.

[0016] The laser light source 22 is composed of a laser oscillator or the like. The laser light LA ​​emitted from the laser light source 22 is reflected by a beam splitter 24 and irradiated onto the cantilever 10. The laser light LA ​​irradiated onto the cantilever 10 is reflected by the back surface of the cantilever 10 and is incident on a reflecting mirror 26. The laser light LA ​​incident on the reflecting mirror 26 is incident on a detector 28 via the reflecting mirror 26. Note that the reflecting mirror 26 is not essential to the present disclosure. The scanning probe microscope 1 may be configured so that the laser light reflected by the cantilever 10 is incident on the detector 28 without passing through the reflecting mirror 26.

[0017] The detector 28 has a light receiving surface 280 for receiving the laser light LA ​​reflected by the cantilever 10. The detector 28 detects the laser light LA ​​received by the light receiving surface 280 and outputs the detection result to the control device 100.

[0018] The driving device 30 moves the laser light source 22 along the YZ plane. The control device 100 controls the driving device 30 to adjust the position of the laser light source 22 so that the laser light LA ​​is incident on the back surface of the cantilever 10. This adjusts the optical axis of the laser light source 22.

[0019] The driving device 40 moves the detector 28 along the YZ plane. In other words, the driving device 40 moves the detector 28 along a plane intersecting the optical axis of the laser beam LA incident on the light-receiving surface 280. The control device 100 controls the driving device 40 to adjust the position of the detector 28 so that the laser beam LA reflected by the back surface of the cantilever 10 is incident on the light-receiving surface 280. More preferably, the control device 100 controls the driving device 40 to adjust the position of the detector 28 so that the laser beam LA reflected by the back surface of the cantilever 10 is incident on the center of the light-receiving surface 280.

[0020] The scanner 50 has a cylindrical shape. The scanner 50 has an XY scanner that scans the sample S in two mutually orthogonal X and Y axis directions, and a Z scanner that slightly moves the sample S in the Z axis direction that is orthogonal to the X and Y axes. The scanner 50 is driven in three dimensions by the XY scanner and the Z scanner. A sample holder 52 is placed on the scanner 50. The sample holder 52 holds the sample S.

[0021] The control device 100 controls the XY scanner and the Z scanner to change the relative positional relationship between the sample S on the scanner 50 and the probe 12 .

[0022] The camera 60 is disposed above the probe 12. The camera 60 captures an image of the cantilever 10 from above. The camera 60 outputs image data to the control device 100. The image data acquired by the camera 60 is used, for example, to adjust the optical axis of the laser light LA ​​directed from the beam splitter 24 to the cantilever 10.

[0023] The control device 100 controls the operation of each component of the scanning probe microscope 1. The control device 100 includes a processor 120, a memory 140, a display device 160, and an input interface 180. The control device 100 constitutes a computer.

[0024] The processor 120 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or an MPU (Multi Processing Unit). The processor 120 realizes each process of the control device 100 by reading and executing a program stored in the memory 140. Note that while the example in FIG. 1 illustrates a configuration with a single processor, the control device 100 may have multiple processors.

[0025] The memory 140 is realized by a non-volatile memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, etc. The memory 140 stores programs executed by the processor 120, data used by the processor 120, etc.

[0026] The memory 140 may be 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, an optical card, a mask ROM, or an EPROM, as long as it can non-temporarily record a program in a format readable by the control device 100, which is a type of computer.

[0027] The display device 160 is configured by a liquid crystal display panel, etc. The display device 160 displays, for example, the measurement results measured by the scanning probe microscope 1, or various setting screens for performing measurements by the scanning probe microscope 1, etc.

[0028] The input interface 180 is configured with a mouse, a keyboard, etc. The input interface 180 is an input interface that receives information input via the input interface 180. Note that the control device 100 may be provided with a touch panel in which the display device 160 and the input interface 180 are integrated.

[0029] [Adjustment During the Approach Period] Figure 2 is a diagram for explaining an outline of a method for adjusting the position of the detector 28 during the approach period. After performing an initial adjustment process, the scanning probe microscope 1 goes through the approach period and then performs a process for measuring the sample. Here, the initial adjustment process includes a process for adjusting the optical axis of the laser light source 22 and a process for adjusting the position of the detector 28. In the process for adjusting the position of the detector 28, the position of the detector 28 is adjusted so that the laser light LA ​​reflected by the cantilever 10 is incident on the reference position P1 on the light-receiving surface 280. As a result, the spot of the laser light LA ​​is positioned at the reference position P1 on the light-receiving surface 280.

[0030] When the light receiving surface 280 is square, the reference position P1 may be set to the intersection of two diagonals of the light receiving surface 280. When the light receiving surface 280 is circular, the center of the light receiving surface 280 may be set to the reference position P1.

[0031] 2(A) to 2(C), a sample S is placed on the sample holder 52. As shown in FIGS. 2(A) and 2(B), during the approach period, the scanner 50 on which the sample holder 52 is placed is brought closer to the probe 12 so that the probe 12 can measure the sample S.

[0032] When the scanning probe microscope 1 operates in contact mode, for example, the scanner 50 is moved closer to the probe 12 until the probe 12 is pressed against the surface of the sample S. In contact mode, the scanning probe microscope 1 measures the sample S after such an approach period.

[0033] Note that even when operating in tapping mode, the scanning probe microscope 1 begins measurement after an approach period. In tapping mode, the approach period ends with a gap between the probe 12 and the sample S. After the approach period ends, the scanning probe microscope 1 vibrates the cantilever 10 at a specified frequency and begins measurement of the sample S.

[0034] Hereinafter, the target position of the probe 12 with respect to the sample S will also be referred to as the "operating point." During the approach period, the scanning probe microscope 1 moves the scanner 50, on which the sample holder 52 is placed, closer to the probe 12 until the position of the probe 12 with respect to the sample S reaches the operating point. Note that instead of moving the scanner 50 toward the probe 12, the cantilever 10 may be moved toward the sample holder 52 on which the sample S is placed.

[0035] During the approach period, the cantilever 10 may gradually bend before contacting the sample S due to the influence of electrostatic force, laser heat, etc. Figure 2(A) corresponds to the initial stage of the approach period, and shows a state in which the cantilever 10 is not bent. At this time, the laser light LA ​​reflected by the cantilever 10 is incident on the reference position P1 of the light receiving surface 280.

[0036] FIG. 2B shows how the cantilever 10 bends as the approach period progresses. As shown in FIG. 2B, as the bending of the cantilever 10 increases, the position of the laser beam LA incident on the light-receiving surface 280 gradually shifts in the bending direction of the cantilever 10. Therefore, the position of the detector 28, which was properly adjusted in the initial adjustment process, may no longer be appropriate for measurement during the approach period. As the amount of bending of the cantilever 10 accumulates during the approach period, the laser beam LA reflected by the cantilever 10 may not even be incident on the light-receiving surface 280. FIG. 2B shows an example in which the incident position of the laser beam LA shifts beyond the reference range E1 set for the light-receiving surface 280.

[0037] When operating in contact mode, the control device 100 determines that the probe 12 has reached the operating point based on the "amount of deflection of the cantilever 10 detected after the probe 12 comes into contact with the sample S." However, even though the cantilever 10 has been deflected before it comes into contact with the sample S due to the influence of electrostatic force or the like, if the control device 100 moves the probe 12 closer to the sample S up to the operating point based on the "amount of deflection of the cantilever 10 detected after the probe 12 comes into contact with the sample S," the probe 12 will be pressed against the sample S at a depth deeper than expected. As a result, problems such as severe wear on the probe 12 or inability to properly acquire measurement images when measuring soft samples may occur.

[0038] Therefore, if the control device 100 detects a positional deviation of the laser beam LA incident on the light-receiving surface 280 during the approach period, it controls the drive device 40 (see FIG. 1) to move the detector 28 and correct the positional deviation. The control device 100 repeatedly executes feedback control during the approach period to correct the positional deviation when a positional deviation is detected. FIG. 2C shows how the incident position of the laser beam LA is corrected to the reference position P1 on the light-receiving surface 280 by executing feedback control.

[0039] As described above, the control device 100 controls the driving device 40 during the approach period in which the probe 12 approaches the sample S, thereby adjusting the position of the detector 28 so that the laser light LA ​​reflected by the cantilever 10 is incident on the light receiving surface 280. According to this embodiment, the detector 28 can be maintained at an appropriate position during the approach period before the measurement process.

[0040] [Explanation of Processing Procedure Based on Flowchart] Fig. 3 is a flowchart showing the processing procedure executed by the control device 100. In addition to the flowchart, Fig. 3 also shows an example of an operating point in the contact mode. Fig. 4 is a flowchart showing the details of the subroutine shown in Fig. 3. The processing procedure of the control device 100 will be described below based on the flowchart.

[0041] First, the control device 100 executes an initial adjustment process (step S1). The initial adjustment process includes a process for adjusting the optical axis of the laser light source 22 and a process for adjusting the position of the detector 28. Next, the control device 100 executes an approach operation for bringing the probe 12 and the sample S closer together (step S2). This starts the approach period.

[0042] Next, the control device 100 executes a subroutine during the approach period (step S3). Details of the subroutine will be described later with reference to FIG. 4. Next, the control device 100 determines whether TR1 has elapsed (step S4). Here, TR1 is a value that defines the time interval for checking whether the probe 12 has reached the operating point. If TR1 has not elapsed, the control device 100 returns the process to step S2.

[0043] If TR1 has elapsed, the control device 100 resets TR1 (step S5) and determines whether the probe 12 has reached the operating point (step S6). If the probe 12 has not reached the operating point, the control device 100 returns the process to step S2. In this way, during the approach period, the control device 100 determines whether the probe 12 has reached the set position (operating point) relative to the sample S every TR1. Therefore, TR1 can also be said to be a value that defines the time interval for checking the completion of the approach.

[0044] When the probe 12 reaches the operating point, the control device 100 ends the approach operation (step S7). This ends the approach period. Next, the control device 100 executes a measurement process for measuring the sample S (step S8), and then ends the process based on this flowchart.

[0045] Next, the subroutine shown in Fig. 3 will be described in detail with reference to Fig. 4. First, the control device 100 determines whether TR2 has elapsed (step S31). Here, TR2 is a value that defines the time interval for checking the necessity of feedback control. In other words, TR2 is a value that defines the time interval for checking whether the cantilever 10 is deflected.

[0046] If TR2 has not elapsed, the control device 100 returns the process to S4 in the flowchart of Fig. 3. If TR2 has elapsed, the control device 100 resets TR2 (step S32) and then executes the feedback control described with reference to Fig. 2. In this way, the control device 100 executes feedback control every time TR2 elapses during the approach period.

[0047] The value of TR2 is larger than the value of TR1 described with reference to Figure 3. TR1 is set to an extremely short time. As already described, in contact mode, the control device 100 determines that the probe 12 has reached the "operating point" based on the "amount of deflection of the cantilever 10 detected after contact with the sample S."

[0048] After the probe 12 comes into contact with the sample S, the cantilever 10 bends suddenly, and the probe 12 eventually reaches the operating point. Therefore, in order to accurately determine the timing when the probe 12 reaches the operating point, it is desirable to set TR1 to a short time.

[0049] The cantilever 10 gradually bends due to the influence of electrostatic force, laser heat, etc., but the amount of bending per unit time at this time is significantly smaller than the amount of bending per unit time from when the probe 12 contacts the sample S until the probe 12 reaches the operating point. For this reason, TR2 is set to a time longer than TR1.

[0050] For example, if the approach period is about one minute, TR1 may be set to several milliseconds (ms) and TR2 may be set to several hundred ms. TR1 is an example of the first time period, and TR2 is an example of the second time period.

[0051] Feedback control is achieved by steps S33 and S34. That is, the control device 100 determines whether the spot position of the laser beam LA has deviated from the reference range E1 on the light-receiving surface 280 (step S33). If the spot position of the laser beam LA has not deviated from the reference range E1, the control device 100 returns the process to S4 in the flowchart of FIG. 3. If the spot position of the laser beam LA has deviated from the reference range E1, the control device 100 adjusts the position of the detector 28 so that the spot of the laser beam LA is positioned at the reference position P1 on the light-receiving surface 280 (step S34). Thereafter, the control device 100 returns the process to S4 in the flowchart of FIG. 3.

[0052] [Modification (Flowchart)] Here, a modification of the flowchart described with reference to Fig. 3 will be described. In Fig. 3, step S100 used in the modification is indicated by a dashed line. As a modification, a flowchart in which step S100 is added before step S1 may be adopted in this embodiment.

[0053] In this case, the control device 100 sets TR2 based on the user's setting operation (step S100). As already explained, TR2 is a value that defines the time interval for checking the necessity of feedback control.

[0054] The degree to which the cantilever 10 bends due to the influence of electrostatic force, laser heat, and the like varies depending on the material of the cantilever 10. According to a modified example, the user can set TR2 taking into account the material of the cantilever 10. Note that in step S100, the control device 100 may accept a user operation to set TR1 and TR2.

[0055] [Modification (Subroutine)] Next, a modification of the subroutine will be described with reference to FIG. 5 . FIG. 5 is a flowchart showing the procedure of the subroutine according to the modification. The subroutine shown in FIG. 5 has additional steps S331 and S332 compared to the subroutine shown in FIG. 4 . As shown in FIG. 5 , when the spot position of the laser beam LA deviates from the reference range E1 (YES in step S33), the control device 100 determines whether the magnitude of the deviation is greater than a reference value M (step S331). When the magnitude of the deviation is greater than the reference value M, the control device 100 transmits an alarm signal to the display device 160 to display alarm information (step S332).

[0056] As a result, alarm information is displayed on the display device 160. The alarm information may be, for example, a message such as "The cantilever is bending significantly." The display device 160 is an example of an alarm device. A speaker may be used instead of or in addition to the display device 160. In this case, the control device 100 may cause the speaker to output the message "The cantilever is bending significantly."

[0057] According to the modified example, when the cantilever 10 is suddenly bent due to the influence of electrostatic force, laser heat, or the like, the user can be notified of the sudden bending of the cantilever 10 .

[0058] 4 and 5, a step of determining whether or not the probe 12 has come into contact with the sample S may be provided before the feedback control (steps S33 and S34). The configuration of the subroutine may be modified so that if it is determined that the probe 12 has come into contact with the sample S, the feedback control is executed, and if it is determined that the probe 12 has not come into contact with the sample S, the feedback control is not executed.

[0059] This prevents the position of the detector 28 from being adjusted to the reference position P1 during the period from when the probe 12 contacts the sample S until when the probe 12 reaches the operating point. Such control is particularly effective in the contact mode. According to this modification, the control device 100 does not execute the process of adjusting the position of the detector 28 so that the laser light reflected by the cantilever 10 is incident on the light-receiving surface 280 after the probe contacts the sample during the approach period. Alternatively, the control device 100 adjusts the position of the detector 28 so that the laser light reflected by the cantilever 10 is incident on the light-receiving surface 280 before the probe contacts the sample during the approach period.

[0060] Other Modifications Other modifications will be described below. When the spot position of the laser beam LA deviates from the reference range E1 on the light-receiving surface 280, the control device 100 may adjust the position of the detector 28 so that the spot of the laser beam LA falls within at least the reference range E1. In other words, the control device 100 only needs to adjust the position of the detector 28 to such an extent that the spot of the laser beam LA falls within the reference range E1, and does not need to adjust the position of the detector 28 so that the spot of the laser beam LA coincides with the reference position P1.

[0061] When the spot position of the laser beam LA is deviated from the reference position P1 on the light-receiving surface 280, the control device 100 may adjust the position of the detector 28 so that the spot of the laser beam LA is positioned at the reference position P1. In this case, too, the position of the detector 28 is adjusted so that the laser beam LA reflected by the cantilever 10 is incident on the reference range E1 on the light-receiving surface 280.

[0062] The reference range E1 may be set to the entire surface of the light receiving surface 280. In this case, when the position of the spot of the laser beam LA deviates from the light receiving surface 280, the control device 100 executes feedback control.

[0063] When the control device 100 adjusts the position of the detector 28 through feedback control, the control device 100 may display a message on the display device 160 indicating that the position of the detector 28 has been adjusted.

[0064] Aspects It will be understood by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0065] (Item 1) A scanning probe microscope according to one aspect comprises a cantilever having a probe, a laser light source for irradiating laser light onto the cantilever, a detector including a light-receiving surface and detecting the laser light incident on the light-receiving surface, a drive device for moving the detector along a plane intersecting the optical axis of the laser light incident on the light-receiving surface, and a control device, wherein the control device controls the drive device during an approach period in which the probe approaches a sample, thereby adjusting the position of the detector so that the laser light reflected by the cantilever is incident on the light-receiving surface.

[0066] According to the scanning probe microscope described in paragraph 1, the detector that detects the laser light can be maintained at an appropriate position during the approach period.

[0067] (Item 2) In the scanning probe microscope described in item 1, the control device adjusts the position of the detector during the approach period so that the laser light reflected by the cantilever is incident on the reference range of the light-receiving surface.

[0068] According to the scanning probe microscope described in paragraph 2, the incident position of the laser light can be maintained within the reference range during the approach period.

[0069] (Clause 3) In the scanning probe microscope described in paragraph 2, the control device determines whether the probe has reached a set position relative to the sample every first time during the approach period, and the control device determines the relationship between the position of the laser light and the reference range every second time, which is longer than the first time, during the approach period.

[0070] According to the scanning probe microscope described in paragraph 3, appropriate control is performed during the approach period, taking into consideration the length of time during which the cantilever is deflected due to the influence of electrostatic force, laser heat, and the like.

[0071] (4) In the scanning probe microscope according to the third aspect, the control device accepts an operation for setting the second time period.

[0072] According to the scanning probe microscope described in item 4, the user can set the second time to various times in consideration of the type of cantilever and the like.

[0073] (5) The scanning probe microscope described in any one of paragraphs 2 to 4 further includes an alarm device configured to output an alarm, and the control device sends a signal to the alarm device to output an alarm when the magnitude of the deviation between the position of the laser light on the light receiving surface and a reference range exceeds a reference value.

[0074] According to the scanning probe microscope described in item 5, the user can grasp the degree to which the cantilever is deflected due to the influence of electrostatic force, laser heat, and the like.

[0075] (Item 6) A method according to one aspect is a method for approaching a probe of a cantilever provided in a scanning probe microscope apparatus to a sample, the scanning probe microscope apparatus comprising: a laser that directs laser light onto the cantilever; a detector including a light-receiving surface that detects the laser light that has entered the light-receiving surface; and a drive device that moves the detector along a plane that intersects with the optical axis of the laser light that has entered the light-receiving surface, the method having a computer execute the steps of: approaching the probe to the sample; and adjusting the position of the detector so that the laser light reflected by the cantilever irradiates the light-receiving surface by controlling the drive device during an approach period in which the probe is approached to the sample.

[0076] According to the method described in item 6, the detector that detects the laser light can be maintained at an appropriate position during the approach period.

[0077] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0078] 1 Scanning probe microscope, 10 Cantilever, 12 Probe, 14 Holder, 20 Optical system, 22 Laser light source, 24 Beam splitter, 26 Reflecting mirror, 28 Detector, 30, 40 Drive device, 50 Scanner, 52 Sample holder, 60 Camera, 100 Control device, 120 Processor, 140 Memory, 160 Display device, 180 Input interface, 280 Light receiving surface, 282 Photodiode, 284 Boundary line, LA Laser light, P1 Reference position, E1 Reference range, S Sample.

Claims

1. A scanning probe microscope comprising: a cantilever having a probe; a laser light source for irradiating laser light onto the cantilever; a detector including a light-receiving surface and detecting the laser light incident on the light-receiving surface; a drive device for moving the detector along a plane intersecting the optical axis of the laser light incident on the light-receiving surface; and a control device, wherein the control device controls the drive device during an approach period in which the probe approaches a sample, thereby adjusting the position of the detector so that the laser light reflected by the cantilever is incident on the light-receiving surface.

2. A scanning probe microscope according to claim 1, wherein the control device adjusts the position of the detector during the approach period so that the laser light reflected by the cantilever is incident on a reference range of the light-receiving surface.

3. A scanning probe microscope as described in claim 2, wherein the control device determines whether the probe has reached a set position relative to the sample every first time during the approach period, and the control device determines the relationship between the position of the laser light and the reference range every second time, which is longer than the first time, during the approach period.

4. The scanning probe microscope according to claim 3, wherein the control device accepts an operation for setting the second time period.

5. A scanning probe microscope as described in claim 2, further comprising an alarm device configured to output an alarm, wherein the control device transmits a signal to the alarm device to output the alarm when the magnitude of the deviation between the position of the laser light on the light receiving surface and the reference range exceeds a reference value.

6. A method for approaching a probe of a cantilever provided in a scanning probe microscope apparatus to a sample, the scanning probe microscope apparatus comprising: a laser that directs laser light onto the cantilever; a detector that includes a light-receiving surface and detects the laser light that has entered the light-receiving surface; and a drive device that moves the detector along a plane that intersects with the optical axis of the laser light that has entered the light-receiving surface, the method comprising having a computer execute the steps of: causing the probe to approach the sample; and controlling the drive device during an approach period in which the probe is approaching the sample, to adjust the position of the detector so that the laser light reflected by the cantilever irradiates the light-receiving surface.

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