Scanning probe microscope and method for adjusting optical axis of scanning probe microscope

Abstract

The present invention provides a scanning probe microscope and an optical axis adjustment method for the scanning probe microscope, which prevent diffuse reflection of laser light from causing adverse effects on the optical axis adjustment process of the laser light of the scanning probe microscope. When the position of the laser light spot determined based on the image captured by the camera unit moves in the direction predicted when the laser light is moved, the control device of the scanning probe microscope uses the determined position of the light spot as the initial position. The control device determines the position where diffuse reflection occurs based on the image captured by the camera unit, and moves the light spot from the initial position to the top of the cantilever in a manner that avoids the position where diffuse reflection occurs.

Description

Technical Field

[0001] The invention relates to a scanning probe microscope and an optical axis adjustment method of the scanning probe microscope. Background Art

[0002] In a scanning probe microscope, a cantilever beam called a cantilever formed with a probe is used. In a scanning probe microscope, the change in the warping or vibration of the cantilever is converted into a change in the reflected light of the laser irradiated to the back of the cantilever, and detected by a photodetector. The photodetector detects changes in the position, intensity, phase, etc. of the reflected light. The scanning probe microscope converts the information detected by the photodetector into various physical information.

[0003] In a scanning probe microscope, before measuring a sample, it is necessary to adjust the optical axis of the laser so that the laser is accurately irradiated to the back of the cantilever. The optical axis adjustment of the laser is a task required every time the cantilever is replaced, so it is desired to be completed in a short time. In addition, the optical axis adjustment of the laser is a task required every time the cantilever is replaced, so it is desired to be performed automatically.

[0004] For example, Patent Document 1 (Patent Gazette No. 6627953) discloses a scanning probe microscope including an image processing unit that determines the position of a laser spot and the position of the tip of a cantilever based on an image. The scanning probe microscope disclosed in Patent Document 1 also includes an optical axis adjustment unit that adjusts the position of a laser light source based on the determined position of the laser spot and the position of the tip of the cantilever.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6627953 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, the spot diameter of the laser in the scanning probe microscope is in the unit of nm to μm. Therefore, there is a risk that the laser may be affected by damage on the irradiation surface of the laser, dust attached to the irradiation surface, or dust floating in the imaging range, resulting in diffuse reflection. The scanning probe microscope disclosed in Patent Document 1 does not take into account the possibility of diffuse reflection of the laser.

[0010] The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to prevent diffuse reflection of laser light from adversely affecting the process of adjusting the optical axis of laser light in a scanning probe microscope.

[0011] Solutions for solving problems

[0012] A scanning probe microscope according to a certain embodiment of the present invention comprises: a cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves the irradiation position of the laser light on the irradiation surface of the laser light relative to the irradiation surface; an imaging unit that includes the cantilever in the imaging range; and a control device. The control device determines a position where the laser light is diffusely reflected based on an image captured by the imaging unit, and the control device moves the irradiation position relative to the irradiation surface by irradiating the cantilever with the laser light via the moving mechanism so as to avoid the position where the laser light is diffusely reflected.

[0013] According to another embodiment of the present invention, a scanning probe microscope includes: a cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves the irradiation position of the laser light on the irradiation surface of the laser light relative to the irradiation surface; an imaging unit that includes at least a portion of the irradiation surface in an imaging range; and a control device. The control device determines the position of the laser spot formed on the irradiation surface based on an image captured by the imaging unit, and determines the irradiation position based on whether the position of the laser spot determined by the image obtained after the irradiation position is moved by the moving mechanism is the position predicted based on the movement of the irradiation position.

[0014] Effects of the Invention

[0015] It is possible to prevent diffuse reflection of laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a diagram schematically showing the structure of a scanning probe microscope 1 according to an embodiment.

[0017] Figure 2 This is a diagram for explaining an outline of an optical axis adjustment method performed at the start of measurement.

[0018] Figure 3 It is a longitudinal sectional view of the upper portion of the scanner 50 and the sample holding portion 52 when the sample S is observed.

[0019] Figure 4 This is an example of an image P obtained when the laser light LA ​​is irradiated with dust or the like and is diffusely reflected.

[0020] Figure 5 This is a diagram for explaining an overview of the position adjustment process S1 of the laser light source 22 executed by the control device 100 .

[0021] Figure 6 1 is a flowchart of the determination process S100.

[0022] Figure 7is an example of image P captured at the initial position.

[0023] Figure 8 Is to make the spot s1 Figure 7 An example of an image P obtained when moving in the moving direction x in .

[0024] Fig. 9 is an example of image P captured at the initial position.

[0025] Fig.10 Is to make the spot s1 Fig. 9 An example of an image P obtained when moving in the moving direction x in .

[0026] Fig.11 This is a flowchart of the adjustment process S300.

[0027] Fig.12 This is a flowchart of the fine adjustment process S330.

[0028] Fig.13 3 is a diagram showing an example of a path that the light spot s1 takes when the adjustment process S300 is executed.

[0029] Description of Reference Numerals

[0030] 1: scanning probe microscope; 10: cantilever; 12: probe; 14: bracket; 20: optical system; 22: laser light source; 24: beam splitter; 26: reflector; 28: detector; 30, 40: driving mechanism; 50: scanner; 52: sample holding part; 54: base part; 60: camera part; 100: control device; 120: processor; 140: memory; 160: display part; 180: input part; 280: light receiving surface; 520: column foot type connector; 522: reflector; 524: magnet; 540: sample stage; LA: laser; P: image; S: sample. DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the following, the same reference numerals are attached to the same or corresponding parts in the drawings, and the description thereof will not be repeated in principle.

[0032] [Structure of Scanning Probe Microscope 1]

[0033] Figure 1 1 is a diagram schematically showing the structure of the scanning probe microscope 1 according to the embodiment. Hereinafter, the ground plane of the scanning probe microscope 1 is defined as an XY plane, and an axis perpendicular to the XY plane is defined as a Z axis.

[0034] Reference Figure 1The scanning probe microscope 1 includes a cantilever 10, a support 14, an optical system 20, drive mechanisms 30 and 40, a scanner 50, a sample holding portion 52, an imaging portion 60, and a control device 100 as main components.

[0035] The cantilever 10 is provided so as to be located above the sample S placed on the sample holding portion 52 during measurement. The cantilever 10 is supported by the holder 14 so as to be vibrable in the vertical direction and has a probe 12 on the side (distal end side) not supported by the holder 14 .

[0036] During measurement, the optical system 20 irradiates the back side of the cantilever 10 (the surface opposite to the surface facing the sample S) with laser light LA, and detects the laser light LA ​​reflected by the back side of the cantilever 10. The control device 100 calculates the 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 reflector 26, and a detector 28.

[0037] The laser light source 22 is composed of a laser oscillator that emits laser light LA. The laser light LA ​​emitted from the laser light source 22 is reflected by the beam splitter 24, and is irradiated to the cantilever 10. The laser light LA ​​irradiated to the cantilever 10 is reflected by the back surface of the cantilever 10, and then reflected by the reflector 26, and is incident on the detector 28. The detector 28 has a light receiving surface 280 for receiving the laser light LA ​​reflected by the back surface of the cantilever 10. The detector 28 detects the laser light LA ​​received by the light receiving surface 280, and outputs the obtained detection result to the control device 100.

[0038] The driving mechanism 30 causes the laser light source 22 to move along a plane (at a position perpendicular to the optical axis of the laser light LA ​​emitted from the laser light source 22) Figure 1 The drive mechanism 30 drives the motor according to the control signal from the control device 100 to move the laser light source 22 so as to adjust the optical axis of the laser light LA ​​in such a way that the laser light LA ​​is reflected by the cantilever 10.

[0039] The drive mechanism 40 causes the detector 28 to move along a plane (at a position perpendicular to the optical axis of the laser light LA ​​reflected by the reflector 26 and incident on the light receiving surface 280) perpendicular to the optical axis of the laser light LA. Figure 1 The driving mechanism 40 drives the motor according to the control signal from the control device 100, so as to move the detector 28, and adjust the position of the detector 28 so that the laser light LA ​​reflected by the cantilever 10 is incident on the center of the light receiving surface 280.

[0040] The scanner 50 has a cylindrical shape. The sample S is held on a sample holding portion 52 placed on the scanner 50. The scanner 50 has an XY scanner and a Z scanner. The XY scanner scans the sample S in two mutually orthogonal X and Y axial directions, and the Z scanner slightly moves the sample S in a Z axis direction orthogonal to the X axis and the Y axis. The XY scanner and the Z scanner use a piezoelectric element that is deformed by a voltage applied from a driving portion not shown as a driving source. The scanner 50 is driven in three dimensions by the XY scanner and the Z scanner.

[0041] The driving unit controls the XY scanner and the Z scanner according to a control signal from the control device 100 , thereby changing the relative positional relationship between the sample S on the scanner 50 and the probe 12 .

[0042] The imaging unit 60 is arranged above the probe 12 and photographs the cantilever 10 from the top. The imaging unit 60 photographs the subject in the imaging field to obtain image data. The imaging unit 60 includes an optical system such as a lens or an aperture, and a light receiving element such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor as main components. The imaging unit 60 outputs the acquired image data to the control device 100. The image data acquired by the imaging unit 60 is used, for example, to adjust the optical axis of the laser LA.

[0043] The control device 100 controls the operation of each unit constituting the scanning probe microscope 1. As an example, the control device 100 is configured according to a general computer architecture. In addition, the control device 100 can also be installed in the scanning probe microscope 1 using dedicated hardware. The control device 100 includes a processor 120, a memory 140, a display unit 160, and an input unit 180.

[0044] The processor 120 is typically a CPU (Central Processing Unit) or an MPU (Multi Processing Unit). The processor 120 reads and executes a program stored in the memory 140 to implement various processes of the control device 100 described below. Figure 1 Although the example of FIG. 1 illustrates a configuration in which a single processor is used, the control device 100 may include a plurality of processors.

[0045] The memory 140 is implemented by a nonvolatile memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), or a flash memory. The memory 140 stores programs executed by the processor 120 or data used by the processor 120. For example, the memory 140 stores a program for executing the position adjustment process S1 of the laser light source 22 and the position adjustment process S2 of the detector 28 described later.

[0046] In addition, as long as the memory 140 can non-temporarily record the program in a form readable by the control device 100 which is a kind of computer, it can be a CD-ROM (Compact Disc-Read Only Memory), DVD-ROM (Digital Versatile Disk-Read Only Memory), USB (Universal Serial Bus) memory, memory card, FD (Flexible Disk), hard disk, SSD (Solid State Drive), magnetic tape, cassette tape, MO (Magnetic Optical Disc), MD (Mini Disc), IC (Integrated Circuit) card (except memory card), optical card, mask ROM, or EPROM.

[0047] The display unit 160 is composed of a liquid crystal display panel, etc. The display unit 160 displays, for example, measurement results measured by the scanning probe microscope 1 or various setting screens for performing measurement using the scanning probe microscope 1 .

[0048] The input unit 180 is composed of a mouse, a keyboard, etc. The input unit 180 is an input interface that receives information inputted via the input unit 180. In addition, the control device 100 may include a touch panel in which the display unit 160 and the input unit 180 are integrated.

[0049] [Optical axis adjustment at the start of measurement]

[0050] In the scanning probe microscope 1, the optical system 20 needs to be adjusted so that the position of the laser light LA ​​reflected by the cantilever 10 (the position with the maximum light receiving amount) when the cantilever 10 is not bent enters the center of the light receiving surface 280 of the detector 28. Such optical axis adjustment is performed every time the cantilever 10 is replaced.

[0051] Figure 2This is a diagram for explaining the outline of the optical axis adjustment method performed at the start of measurement. The processing related to the optical axis adjustment includes a position adjustment processing S1 of the laser light source 22 and a position adjustment processing S2 of the detector 28 .

[0052] When receiving the start instruction of the optical axis adjustment, the control device 100 performs the position adjustment process S1 of the laser light source 22. In the position adjustment process S1 of the laser light source 22, the control device 100 adjusts the position of the laser light source 22 so that the light spot s1 formed by the laser LA irradiating the sample holding portion 52 or the cantilever 10 comes to the position of the top end of the cantilever 10. The control device 100 determines the positional relationship between the light spot s1 and the top end of the cantilever 10 based on the image P generated by the camera 60. The control device 100 controls the driving mechanism 30 based on the determined positional relationship, so that the laser light source 22 moves in the Y direction and the Z direction in the figure so that the light spot s1 is located at the top end of the cantilever 10.

[0053] When the control device 100 determines that the light spot s1 is located at the tip of the cantilever 10, the control device 100 executes the position adjustment process S2 of the detector 28. In addition, the position adjustment process S2 of the detector 28 may be executed in response to receiving a start instruction of the position adjustment process S2 of the detector 28. In the position adjustment process S2 of the detector 28, the control device 100 adjusts the position of the detector 28 so that the light spot s2 of the laser LA reflected by the cantilever 10 (the light spot s2 formed by the laser LA irradiating the light receiving surface 280) is located at the center of the light receiving surface 280.

[0054] In addition, the position adjustment process S2 of the detector 28 may also be performed by the user. Specifically, the scanning probe microscope 1 may also be provided with an operating unit, which is used to drive the driving mechanism 40 that moves the detector 28, and the user operates the operating unit based on the detection result from the detector 28, thereby implementing the position adjustment process S2 of the detector 28.

[0055] [Structure of the Sample Holding Section 52]

[0056] In the present embodiment, the sample holding portion 52 includes a reflecting mirror 522 in order to facilitate detection by the imaging unit 60 of a spot s1 formed on the irradiated surface when the laser light LA ​​is irradiated on the irradiated surface.

[0057] Figure 3 2 is a longitudinal sectional view of the upper portion of the scanner 50 and the sample holding portion 52 when observing the sample S. Figure 3 A substantially ring-shaped base portion 54 is provided on the upper end surface of the scanner 50 , and the base portion 54 has a cylindrical hole in the center.

[0058] The sample holding portion 52 includes a column-type connection member 520 and a sample stage 540 .

[0059] The bottom of the post-type connector 520 is formed into a convex shape. The post-type connector 520 is fixed to the scanner 50 by inserting the convex portion into the cylindrical hole provided in the center of the base portion 54. Alternatively, the post-type connector 520 may be fixed to the scanner 50 by screws or the like.

[0060] A recess 526 is formed on the upper surface of the column-type connector 520, and a reflector 522 is placed inside the recess 526. A magnet 524 is embedded inside the column-type connector 520. The column-type connector 520 is made of aluminum.

[0061] The sample stand 540 is a stand for placing the sample S and is made of metal. When observing the sample, the sample stand 540 is placed on the upper side of the reflector 522. Figure 2 In the optical axis adjustment described above, the sample stage 540 is not placed on the upper side of the reflecting mirror 522 .

[0062] When the sample stage 540 is placed on the upper side of the reflector 522, the sample stage 540 is fixed to the post-type connector 520 due to the attraction of the magnet 524 in the post-type connector 520. In addition, since the reflector 522 is placed inside the recess 526, when the sample stage 540 is placed on the upper side of the reflector 522, a gap is formed between the reflector 522 and the sample stage 540.

[0063] Reference Figure 2 The optical axis adjustment described above is performed without placing the sample stage 540 on the upper side of the reflective mirror 522. Therefore, the laser light LA ​​is not blocked by the sample stage 540 and enters the reflective mirror 522. The laser light LA ​​entering the reflective mirror 522 is not blocked by the sample stage 540 and enters the imaging unit 60.

[0064] In the following, it is assumed that the reference is performed in a state where the sample stage 540 is not placed on the upper side of the reflective mirror 522. Figure 2 The optical axis adjustment described above is explained below. In addition, the optical axis adjustment can also be performed in a state where the sample stage 540 is placed on the upper side of the reflector 522. In addition, when the optical axis adjustment is performed in a state where the sample stage 540 is placed on the upper side of the reflector 522, the optical axis adjustment is performed in a state where the sample S with a high reflectivity is placed on the sample stage 540.

[0065] That is, when the optical axis is adjusted without placing the sample S but with the sample table 540 placed, the surface for placing the sample S is equivalent to the "irradiation surface"; when the optical axis is adjusted with the sample S having a high reflectivity placed on the sample table 540, the surface of the sample S is equivalent to the "irradiation surface"; and when the optical axis is adjusted without placing the sample table 540 on the upper side of the reflector 522, the mirror surface of the reflector 522 is equivalent to the "irradiation surface".

[0066] [Problems that arise when determining the irradiation position of the laser light LA]

[0067] The control device 100 determines the position of the spot s1 formed by the laser LA irradiating the irradiation surface based on the image captured by the imaging unit 60 . The control device 100 uses the determined position of the spot s1 as the irradiation position of the laser LA and performs feedback control to align the irradiation position of the laser LA with the cantilever 10 .

[0068] The spot diameter of the laser LA of the scanning probe microscope 1 is in units of nm to μm. Therefore, the laser LA has the following risk: it is affected by damage formed on the irradiation surface of the laser, dust attached to the irradiation surface, or dust floating in the imaging range, resulting in diffuse reflection. In addition, substances attached to the irradiation surface that cause diffuse reflection include solutions scattered during observation in liquid and dust, but are not limited to them.

[0069] In addition, the imaging range of the imaging unit 60 used when determining the irradiation position of the laser LA is a field of view in units of μm to mm, and when determining the irradiation position of the laser LA, an accuracy in units of nm to μm is required. The imaging range of the imaging unit 60 is in units of μm to mm, so the irradiation position of the laser LA (the position of the spot s1) may not be accurately determined due to diffuse reflection of the laser LA.

[0070] More specifically, refer to Figure 4 This is to explain that the irradiation position of the laser light LA ​​may not be determined due to diffuse reflection of the laser light LA. Figure 4 This is an example of an image P obtained when the laser light LA ​​is irradiated with dust or the like and is diffusely reflected. Figure 4 The shaded area in FIG. 5 is an area D showing the position where the laser light LA ​​is diffusely reflected. In addition, the area highlighted in white is the shadow r (high brightness area) of the laser light LA ​​reflected on the irradiation surface (reflection mirror 522). Figure 4 In the figure, some of the reference numerals are omitted.

[0071] like Figure 4As shown in FIG. 1 , when the laser light LA ​​is diffusely reflected, the reflected light of the laser light LA ​​enters the imaging unit 60 from various directions, and multiple shadows r of the laser light LA ​​appear on the image P. In addition, due to the diffuse reflection of the laser light LA, the spot s1 of the laser light LA ​​may not be formed at the irradiation position. The control device 100 may erroneously determine the shadow r that appears due to the diffuse reflection of the laser light LA ​​as the spot s1, thereby erroneously determining the irradiation position of the laser light LA.

[0072] For example, the irradiation position of the laser LA in the camera coordinates is Figure 4 In the case of position a in Figure 4 The spot s1 is formed at the position b in the image, and the control device 100 may determine the position b as the irradiation position of the laser light LA. That is, as a problem caused by the diffuse reflection of the laser light LA, there is a problem that the irradiation position of the laser light LA ​​cannot be accurately determined.

[0073] The control device 100 starts the optical axis adjustment in a state where the irradiation position of the laser light LA ​​is unknown. Therefore, there is a problem that the irradiation position of the laser light LA ​​cannot be accurately determined, and therefore the initial position of the irradiation position of the laser light LA ​​cannot be accurately determined.

[0074] When the initial position of the irradiation position determined based on the image P at the start of the optical axis adjustment is wrong, the control device 100 adjusts the irradiation position of the laser LA based on the wrong position. As a result, the following problems occur: it takes time to align the irradiation position of the laser LA with the cantilever 10, or the irradiation position of the laser LA cannot be aligned with the cantilever 10.

[0075] In addition, when aligning the irradiation position of the laser LA on the cantilever 10, it is necessary to adjust in units of nm to μm. However, when the position of the laser light source 22 is moved by driving a motor such as the drive mechanism 30, it is difficult to move the irradiation position of the laser LA in units of nm to μm. Therefore, generally, the control device 100 performs feedback control based on the image captured by the camera unit 60 to align the irradiation position of the laser LA.

[0076] In order to implement feedback control, the control device 100 needs to determine the irradiation position of the laser LA by determining the position of the light spot s1 based on the image captured by the camera unit 60. However, as described above, when the laser LA is diffusely reflected, the control device 100 may not be able to correctly determine the irradiation position of the laser LA. Therefore, even if the initial position of the laser LA can be correctly determined, there is a risk that the laser LA is diffusely reflected during the movement of the irradiation position of the laser LA, and the correct irradiation position cannot be determined, so that correct feedback control cannot be performed. That is, as a problem caused by the diffuse reflection of the laser LA, there is a problem that correct feedback control cannot be performed.

[0077] That is, due to the diffuse reflection of the laser LA, problems such as the inability to accurately determine the irradiation position of the laser LA, the inability to determine the initial position of the irradiation position, or the inability to perform accurate feedback control occur, which has a negative impact on the process of adjusting the optical axis of the laser LA.

[0078] [Laser Light Source 22 Position Adjustment Process S1]

[0079] Figure 5 1 is a diagram for explaining an overview of the position adjustment process S1 of the laser light source 22 performed by the control device 100. In the present embodiment, the control device 100 determines the spot s1 of the laser LA based on the image generated by the imaging unit 60, and controls the driving mechanism 30 to adjust the position of the laser light source 22 so that the irradiation position of the laser LA is located at the tip of the cantilever 10.

[0080] In order to solve the problem that the initial position of the irradiation position of the laser light LA ​​cannot be accurately determined, the scanning probe microscope 1 according to the present embodiment performs a process of determining the initial position of the irradiation position (determination process S100). Figure 6 to Figure 10 The determination process S100 will be described later.

[0081] After the initial position of the irradiation position is determined in the determination process S100, the scanning probe microscope 1 according to the present embodiment performs a process of adjusting the irradiation position of the laser light LA ​​(adjustment process S300) in order to solve the problem that accurate feedback control cannot be performed. Figure 11 to Figure 13 The adjustment process will be described later. When the control device 100 ends the adjustment process, the position adjustment process S1 of the laser light source 22 ends.

[0082] [Confirm processing]

[0083] Reference Figure 6 The determination process S100 will be described in detail. Figure 6 1 is a flowchart of the determination process S100.

[0084] In S102, the control device 100 determines whether the light spot s1 is detected. More specifically, the control device 100 determines whether the light spot s1 is formed on the irradiated surface included in the imaging range of the imaging unit 60. For example, the control device 100 determines whether the light spot s1 is detected based on whether the image contains a predetermined number or more of pixels whose brightness is greater than a predetermined threshold.

[0085] When it is determined that the light spot s1 is not detected (S102: No), the control device 100 changes the irradiation position in S104. More specifically, the control device 100 controls the drive mechanism 30 to move the laser light source 22, thereby changing the irradiation position.

[0086] The control device 100 repeats the processes of S102 and S104 until the light spot s1 is detected. When the control device 100 determines that the light spot s1 is detected (S102: Yes), the control device 100 executes the process of S106.

[0087] In S106, the control device 100 determines the position of the light spot s1. More specifically, the control device 100 determines the position of the light spot s1 in the image (in the camera coordinates). For example, the control device 100 determines an area close to a predetermined area (number of pixels) in an area representing pixels having a brightness greater than a predetermined threshold, and uses the position of the determined area in the image as the position of the light spot s1. For example, the predetermined area (number of pixels) is set in advance based on the intensity of the laser LA, the distance from the laser light source 22 to the irradiation surface, and the distance from the irradiation surface to the imaging unit 60.

[0088] In S108 , the control device 100 stores the position of the laser light source 22 as the initial position.

[0089] In S110, the control device 100 sets the moving direction x. The moving direction x is the direction in which the light spot s1 moves relative to the irradiated surface.

[0090] In S112 , the control device 100 moves the irradiation position in the moving direction x. More specifically, the control device 100 controls the drive mechanism 30 to move the laser light source 22 in a direction corresponding to the moving direction x, thereby moving the light spot s1 relative to the irradiation surface in the moving direction x.

[0091] In S114 , the control device 100 specifies the position of the light spot s1 based on the image captured in the state of having moved in the moving direction x.

[0092] In S116, the control device 100 determines whether the light spot s1 on the image has moved in the moving direction x. More specifically, the control device 100 determines whether the moving direction of the light spot s1 on the image predicted when the laser light source 22 is moved in the moving direction x relative to the irradiated surface is consistent with the moving direction from the position of the light spot determined in S106 to the position of the light spot determined in S114.

[0093] When determining that the light spot s1 has not moved in the moving direction x on the image (S116: No), the control device 100 determines whether all directions are set in S118. More specifically, the control device 100 determines whether the light spot s1 has moved in all predetermined directions around the initial position.

[0094] If it is determined that all directions have not been set (S118: No), that is, if there is a moving direction x that has not been set, the control device 100 returns the position of the laser light source 22 to the initial position in S120 and executes the processes of S110 to S116 again. In addition, in S110, the control device 100 sets the moving direction x to be set next based on the currently set moving direction x.

[0095] When it is determined that all directions are set (S118: YES), the control device 100 determines that an abnormality exists in S122 and ends the process. In this case, the control device 100 ends the process related to the optical axis adjustment.

[0096] When it is determined that the light spot s1 has moved in the moving direction x on the image (S116: Yes), the control device 100 moves the irradiation position by a predetermined distance in the moving direction x in S124. More specifically, the control device 100 controls the drive mechanism 30 to move the laser light source 22, so that the light spot s1 moves by a predetermined distance relative to the irradiation surface. For example, the distance to be moved is set in advance according to the imaging range of the imaging unit 60.

[0097] In S126, the control device 100 determines whether the light spot s1 has moved in the moving direction x on the image. More specifically, during the movement of the predetermined distance, the control device 100 controls the imaging unit 60 to acquire images at a predetermined time, and determines the position of the light spot s1 for each image acquired at each time. The control device 100 determines whether the light spot s1 has continued to move in the moving direction x on the image by comparing the position of each light spot s1 determined for each image with the position of the light spot determined in S106.

[0098] When it is determined that the light spot s1 has not moved in the moving direction x on the image (S126: No), the control device 100 executes the processing after S118. That is, when all directions are set, the control device 10 considers that there is an abnormality and ends the processing. When there is a direction that is not set, the direction is changed and the processing after S110 is executed again.

[0099] When it is determined that the light spot s1 is moving in the moving direction x on the image (S126: YES), the control device 100 returns the position of the laser light source 22 to the initial position in S128 and ends the determination process S100. When the determination process S100 is ended, the control device 100 returns to the position adjustment process S1 of the laser light source 22.

[0100] That is, the control device 100 changes the moving direction x in sequence by repeating S110 to S120. Then, when the moving direction of the light spot s1 detected on the image does not match the moving direction x of the irradiation position actually moved in any moving direction x (S118: "Yes"), the control device 100 considers that an abnormality exists in S122 and ends the processing. Here, "abnormality exists" in S122 means that the initial position of the irradiation position of the laser LA cannot be determined.

[0101] For example, when the laser light LA ​​is diffusely reflected at the initial position or when the laser light LA ​​is diffusely reflected regardless of the movement in any movement direction x, the control device 100 determines that an abnormality exists in S122 .

[0102] In addition, even if the laser LA is diffusely reflected at the initial position and the position of the light spot s1 determined in S106 is different from the irradiation position, the moving direction of the position of the light spot s1 detected on the image coincides with the moving direction x of the actual movement by chance. In this embodiment, by executing the processing of S124 and S126, it is possible to determine whether the position of the light spot s1 determined in S106 is correct by considering the situation that the moving direction of the position of the light spot s1 detected on the image coincides with the moving direction x of the actual movement by chance.

[0103] In addition, by executing the processes of S124 and S126 , it is ensured that the region D is not located on the trajectory of the light spot s1 moved in S124 .

[0104] In addition, the control device 100 may display information indicating that the initial position cannot be determined on the display unit 160 when it is considered that an abnormality exists. In addition, the control device 100 may display information indicating a method of eliminating the abnormality on the display unit 160. The “method of eliminating the abnormality” includes, for example, a method of manually determining the initial position, a method of removing dust attached to the reflector 522, and a method of moving the reflector 522 so that an area with less damage or dust on the mirror surface of the reflector 522 is within the imaging range.

[0105] Reference Figure 7 to Figure 10 An example of an image obtained by executing the determination process S100 will be described. Figure 7 and Fig. 9 is an example of an image P captured at the initial position. Figure 8 Is to make the spot s1 Figure 7 An example of an image P obtained when moving in the moving direction x in . Fig.10 Is to make the spot s1 Fig. 9 An example of an image P obtained when moving in the moving direction x in . Figure 7 to Figure 10 The area shown by the shade in FIG. 5 is the area D where the laser light LA ​​is diffusely reflected. The area shown by the highlight is the shadow r (high brightness area) of the laser light LA ​​reflected by the irradiation surface (reflection mirror 522). Figure 7 to Figure 10 In the figure, some of the reference numerals are omitted.

[0106] Figure 7 to Figure 10 The x-coordinate and y-coordinate of are camera coordinates, and the x-coordinate and y-coordinate are coordinates based on the scanning probe microscope 1 . Figure 7 to Figure 10 The positions a and a' in represent the irradiation positions of the laser LA on the irradiation surface (on the XY coordinates). The positions b and b' represent the positions of the light spot s1 determined by the control device 100 based on the image P on the camera coordinates.

[0107] exist Figure 7 In the example shown in FIG. 1 , the laser LA is irradiated to the region D (position a (X1, Y1)) where diffuse reflection occurs. In this case, Figure 7 As shown in FIG. 1 , due to diffuse reflection of the laser LA, multiple shadows of the laser LA appear on the image P. As a result, Figure 7 In the example shown, the control device 100 determines that the light spot s1 is formed at the position b(x1, y1) ( Figure 6 That is, the control device 100 determines that the initial position of the irradiation position on the camera coordinates is the position b (x1, y1).

[0108] exist Figure 7When the irradiation position is moved in the moving direction x in ( Figure 6 S112 in Figure 8 As shown, the irradiation position of the laser LA is separated from the position where diffuse reflection occurs (region D), and the light spot s1 is formed at the position a'(X2, Y2) on the irradiated surface, and the formed light spot s1 is presented on the image P. Then, the control device 100 determines that the position of the light spot s1 is the position b'(x2, y2) ( Figure 6 That is, the control device 100 determines that the irradiation position on the camera coordinates is the position b'(x2, y2).

[0109] like Figure 8 As shown in FIG. 1 , the moving direction x from position a (X1, Y1) to position a' (X2, Y2) is inconsistent with the moving direction x' from position b (x1, y1) to position b' (x2, y2). In this case, the control device 100 Figure 6 In S116, it is determined that the light spot s1 has not moved in the moving direction x on the image P, and the processing after S118 is executed.

[0110] In contrast, Fig. 9 In the example shown, it is assumed that the laser LA is not irradiated to the diffuse reflection region D, and the light spot s1 is formed at the irradiation position a (X3, Y3), and the formed light spot s1 is presented on the image P. Then, the control device 100 determines that the initial position of the light spot s1 is the position b (x3, y3) ( Figure 6 That is, the control device 100 determines that the initial position of the irradiation position on the camera coordinates is the position b (x3, y3).

[0111] exist Fig. 9 When the irradiation position is moved in the moving direction x in ( Figure 6 S112 in Fig.10 As shown, the laser LA does not irradiate the diffusely reflected region D, and the light spot s1 is formed at the irradiation position a'(X4, Y4), and the formed light spot s1 is presented on the image P. Then, the control device 100 determines that the position of the light spot s1 is the position b'(x4, y4) ( Figure 6 That is, the control device 100 determines that the irradiation position on the camera coordinates is the position b'(x4, y4).

[0112] like Fig.10 As shown, the moving direction x from position a (X3, Y3) to position a' (X4, Y4) is consistent with the moving direction x' from position b (x3, y3) to position b' (x4, y4). Figure 6In S116, it is determined that the light spot s1 is moving in the moving direction x on the image P, and the processing after S124 is executed.

[0113] like Figure 7 and Figure 8 As shown, if the irradiation position does not move in the moving direction before and after the determined position of the light spot s1 moves, there is a high possibility that the laser LA is diffusely reflected at least one of before and after the movement. Also, there is a high possibility that the irradiation position of the laser LA on the image P is incorrect.

[0114] On the other hand, Fig. 9 and Fig.10 As shown, if the irradiation position is moving in the direction of the movement before and after the determined position of the light spot s1, it is highly likely that the laser LA is not diffusely reflected before and after the movement. Furthermore, it is highly likely that the irradiation position of the laser LA on the image P is correct.

[0115] That is, in the present embodiment, the control device 100 determines the position of the spot s1 of the laser LA formed on the irradiation surface based on the image P captured by the imaging unit 60. Then, the control device 100 controls the driving mechanism 30 to move the position of the laser light source 22, thereby changing the irradiation position of the laser LA, and determines the irradiation position based on whether the position of the spot s1 determined based on the image P obtained after the irradiation position is changed is the position predicted based on the change of the irradiation position.

[0116] More specifically, the control device 100 moves the irradiation position in the movement direction x, and when the position of the spot s1 identified based on the image before the movement does not move in the movement direction x, determines that the identified position of the spot s1 does not correspond to the irradiation position.

[0117] In addition, in the above-mentioned embodiment, the control device 100 moves the irradiation position in the moving direction x, and even if the position of the light spot s1 determined based on the image before the movement has moved in the moving direction x, the irradiation position is further moved by a predetermined distance in the moving direction x. Then, when the position of the light spot s1 determined based on the image has moved in the moving direction x in coordination with the movement of the irradiation position, the control device 100 determines that the position of the light spot s1 determined based on the image is equivalent to the irradiation position.

[0118] In addition, the control device 100 may move the irradiation position in the moving direction x instead of executing S124 and S126. When it is determined that the position of the light spot s1 determined based on the image before the movement has moved in the moving direction x (S116: "Yes"), the position of the light spot s1 determined based on the image is equivalent to the irradiation position, and the processing of S128 is executed.

[0119] [Adjustment Processing]

[0120] As described above, the control device 100 performs feedback control based on the image captured by the imaging unit 60, thereby aligning the irradiation position of the laser LA. However, when the laser LA is diffusely reflected, the control device 100 may not be able to correctly determine the irradiation position of the laser LA based on the image P. Therefore, the control device 100 involved in this embodiment performs adjustment processing S300 to determine the position where the laser LA is diffusely reflected, so as to align the irradiation position of the laser LA to the cantilever 10 in a manner that avoids the laser LA passing through the position where the laser LA is diffusely reflected.

[0121] Reference Fig.11 The adjustment process S300 will be described in detail. Fig.11 This is a flowchart of the adjustment process S300. Fig.11 The adjustment process S300 shown is performed in the following cases: Figure 6 In the determination process S100 shown, an abnormality is considered to exist (S122), and the process related to the optical axis adjustment is terminated, and the position of the laser light source 22 is returned to the initial position (S128), and the process returns to the position adjustment process S1 of the laser light source 22. That is, the adjustment process S300 is executed when the control device 100 determines that the initial position can be correctly determined.

[0122] In S302 , the control device 100 obtains the position of the region D where the laser light LA ​​is diffusely reflected. For example, the control device 100 obtains the region D where the laser light LA ​​is diffusely reflected based on an image obtained in a state where the laser light source 22 is turned off.

[0123] As an example, the control device 100 performs binarization of the image P based on the pixel value. Then, based on the binary image, the control device 100 divides the area other than the cantilever 10 and the bracket 14 (the area corresponding to the mirror surface of the reflector 522) into one or more areas, and for each divided area, accumulates the pixel values ​​in the vertical and horizontal directions (xy directions). The accumulated value of the area where dust or other substances or damage exists (the area including the area D) is larger than the accumulated value of the mirror surface of the reflector 522. Therefore, the control device 100 can obtain the coordinates of the four corners of the area D on the camera coordinates.

[0124] That is, in this embodiment, the control device 100 specifies the position of the region D for diffusely reflecting the laser light LA ​​within the range of the region in the image corresponding to the reflector 522. The region in the image corresponding to the cantilever 10 and the support 14 is specified by, for example, known pattern matching.

[0125] In addition, the method for obtaining the position of the area D on the camera coordinates is not limited to the above method. For example, the control device 100 may perform pre-processing of noise removal on the image, and obtain the position of the area D by comparing the images before and after the noise removal. The filter used in the pre-processing may include an averaging filter, an expansion filter, a contraction filter, a median filter, etc. In addition, the control device 100 may also use a combination of these filters.

[0126] Alternatively, the control device 100 may assume that damage and substances (eg, dust, solution, etc.) are particles and use a general particle analysis method to determine the position of the region D. The method for determining the position of the region D is not limited to the method exemplified above.

[0127] In S304, the control device 100 obtains a target position. The target position is, for example, the tip portion of the cantilever 10 that is not supported by the support 14. In S304, the light spot s1 is located at the initial position of the light spot s1 determined in S106.

[0128] In S306, the control device 100 determines whether it is possible to move toward the target position without passing through the area D. More specifically, the control device 100 determines whether the area D exists in the moving direction from the light spot s1 toward the target position. In addition, if the distance between the light spot s1 and the area D is sufficient, it can be determined that it is possible to move toward the target position without passing through the area D.

[0129] When the control device 100 determines that the light spot s1 cannot move toward the target position ( S306 : No), the control device 100 determines in S308 whether the light spot s1 can move in a direction avoiding the area D. For example, the control device 100 determines whether the light spot s1 can move in the imaging field of the imaging unit 60 to avoid the area D.

[0130] When the control device 100 determines that it is impossible to move in the direction avoiding the area D (S308: No), it is considered that there is an abnormality in S314 and the processing is terminated. In this case, the control device 100 terminates the processing related to the optical axis adjustment. At this time, the control device 100 can display information on the display unit 160 indicating that the position adjustment processing S1 of the laser light source 22 cannot be normally terminated.

[0131] When the control device 100 determines that movement in the direction avoiding area D is possible (S308: Yes), in S310 the irradiation position is moved in the direction avoiding area D. When there are multiple directions avoiding area D, the control device 100 may select a direction closer to the target position.

[0132] After driving the driving mechanism 30 with a predetermined pulse amount in S310, the control device 100 obtains the position of the light spot s1 in S312. After obtaining the position of the light spot s1, the control device 100 executes S306 again to determine whether the light spot s1 can move to the target position without passing through the area D.

[0133] The control device 100 repeats the processes of S308 to S312 until it determines that movement toward the target position is possible without passing through the region D. That is, by repeating the processes of S308 to S312, the control device 100 can move the irradiation position of the laser light LA ​​so as not to pass through the position where diffuse reflection occurs.

[0134] When it is determined that the irradiation position can be moved toward the target position without passing through the area D ( S306 : YES), the control device 100 moves the irradiation position toward the target position in S316 .

[0135] After the control device 100 drives the drive mechanism 30 with a predetermined pulse amount in S316 , it obtains the position of the light spot s1 in S318 .

[0136] In S320 , the control device 100 determines whether the distance between the target position and the position of the spot s1 is equal to or smaller than a predetermined threshold value.

[0137] When it is determined that the distance between the target position and the position of the light spot s1 is longer than a predetermined threshold value ( S320 : No), the control device 100 executes the processes after S306 again to reduce the distance between the target position and the light spot s1 .

[0138] The control device 100 repeats the processing of S306 to S318 until it is determined that the distance between the target position and the position of the light spot s1 is less than a predetermined threshold value. When it is determined that the distance between the target position and the position of the light spot s1 is less than a predetermined threshold value (S320: "Yes"), the control device 100 performs the fine adjustment processing S330, then ends the adjustment processing S300, returns to the position adjustment processing S1 of the laser light source 22, ends the position adjustment processing S1 of the laser light source 22, and performs the position adjustment processing S2 of the detector 28.

[0139] [Micro-adjustment processing]

[0140] Reference Fig.12 The fine adjustment process S330 will be described in detail. Fig.12 This is a flowchart of the fine adjustment process S330. Fig.12 The fine adjustment process S330 shown is a process for aligning the irradiation position with the tip of the cantilever 10 and is executed at a timing when the distance between the target position and the position of the spot s1 is shorter than a predetermined threshold value.

[0141] In S332 , the control device 100 moves the irradiation position toward the target position. The control device 100 continues to move the irradiation position toward the target position until it is determined that the laser light LA ​​has irradiated the cantilever 10 ( S334 : Yes).

[0142] For example, whether the laser LA is irradiated to the cantilever 10 is determined based on whether the light spot s1 is detected. The control device 100 can determine the light spot s1 while the laser LA is irradiated to the mirror surface of the reflector 522. On the other hand, when the surface of the cantilever 10 has a property of diffusely reflecting the laser LA, the control device 100 cannot determine the light spot s1 at the timing when the laser LA is irradiated to the cantilever 10. Therefore, the control device 100 can determine that the laser LA is irradiated to the cantilever 10 based on the fact that the light spot s1 cannot be determined.

[0143] When determining that the cantilever 10 is irradiated with the laser beam LA ( S334 : YES), the control device 100 stores, as the position A, the position of the laser light source 22 at the timing when it is determined that the cantilever 10 is irradiated with the laser beam LA.

[0144] In S338, the control device 100 moves the irradiation position in the same direction. The same direction is the same direction as the direction moved in S332.

[0145] After the control device 100 drives the drive mechanism 30 with a predetermined pulse amount in S338, it is determined in S340 whether the laser LA has separated from the cantilever 10. As in S334, it is determined whether the laser LA has separated from the cantilever 10 based on whether the light spot s1 is detected. The control device 100 can determine that the laser LA has separated from the cantilever 10 based on the fact that the light spot s1 can be identified.

[0146] When it is determined that the laser light LA ​​has not left the cantilever 10 ( S342 : No), the control device 100 determines in S342 whether the light spot s1 has left the imaging field of view.

[0147] When it is determined that the light spot s1 is out of the field of view (S342: Yes), the control device 100 considers that there is an abnormality in S344 and terminates the process. In this case, the control device 100 terminates the process related to the optical axis adjustment. At this time, the control device 100 may display information on the display unit 160 indicating that the position adjustment process S1 of the laser light source 22 cannot be normally terminated.

[0148] When it is determined that the spot s1 has not left the imaging field of view ( S342 : No), the control device 100 executes the process after S338 again, and repeats the process from S338 to S342 until it is determined that the laser light LA ​​has left the cantilever 10 ( S340 : Yes).

[0149] When it is determined that the laser light LA ​​has separated from the cantilever 10 ( S340 : YES), the control device 100 stops the movement of the irradiation position in S346 .

[0150] In S348 , the control device 100 stores the position of the laser light source 22 when it is stopped as position B.

[0151] In S350 , the control device 100 sets the position of the laser light source 22 to a position intermediate between the position A and the position B, ends the fine adjustment process S330 , and returns to the adjustment process S300 .

[0152] That is, in the present embodiment, the control device 100 determines the position of the region D where the laser light LA ​​is diffusely reflected based on the image captured by the imaging unit 60. Then, the control device 100 controls the driving mechanism 30 to move the position of the laser light source 22 so as to irradiate the cantilever 10 with the laser light LA ​​while avoiding the position of the region D where the laser light LA ​​is diffusely reflected, thereby moving the irradiation position of the laser light source 22.

[0153] Furthermore, even when the control device 100 determines that the laser light LA ​​is irradiated onto the cantilever 10, the control device 100 continues to move the irradiation position until the laser light LA ​​cannot irradiate the cantilever 10. Then, the control device 100 determines the position of the laser light source 22 based on the position A of the laser light source 22 when it is determined that the laser light LA ​​is irradiated onto the cantilever 10 and the position B of the laser light source 22 when it is determined that the laser light LA ​​cannot irradiate the cantilever 10. In other words, the control device 100 determines the state of the drive mechanism 30 when starting observation based on the state of the drive mechanism 30 when it is determined that the laser light LA ​​is irradiated onto the cantilever 10 and the state of the drive mechanism 30 when it is determined that the laser light LA ​​cannot irradiate the cantilever 10.

[0154] Furthermore, the control device 100 may use the position A of the laser light source 22 when it is determined that the laser light LA ​​has irradiated the cantilever 10 as the position of the laser light source 22 when the observation is started.

[0155] [Path of the light spot s1 during the execution of the adjustment process S300]

[0156] Reference Fig.13 An example of a path that the light spot s1 (irradiation position) takes by executing the adjustment process S300 will be described. Fig.133 is a diagram showing an example of a path that the light spot s1 takes when the adjustment process S300 is executed.

[0157] For example, in Fig.13 In the example shown, since the area D is located in the direction M of the light spot s1 toward the target position G, the control device 100 controls the drive mechanism 30 to move the light spot s1 along the direction N to avoid the area D ( Fig.11 (S308, S310).

[0158] When the control device 100 continues to control the driving mechanism 30 so that the light spot s1 moves along the direction N ( Fig.11 Even if the light spot s1 is moved toward the target position G, the light spot s1 will be located at a position that does not pass through the area D.

[0159] When the control device 100 determines that the light spot s1 can be moved toward the target position G without passing through the area D ( Fig.11 S306: “Yes”), for example, move the light spot s1 along the direction O.

[0160] In this way, the control device 100 executes Fig.11 The adjustment process S300 shown can align the irradiation position with the target position (the tip of the cantilever 10 ) so as not to pass through the region D where the laser light LA ​​is diffusely reflected.

[0161] [Modification of determination processing]

[0162] In the above embodiment, the spot s1 is moved relative to the irradiation surface by moving the laser light source 22. Alternatively, the initial position of the laser light LA ​​may be determined by moving the reflective mirror 522 as the irradiation surface to move the spot s1 relative to the irradiation surface.

[0163] In this case, the control device 100 can determine that the determined position of the light spot s1 is correct in the determination process S100 because the position of the light spot s1 does not change when the reflection mirror 522 as the irradiation surface is moved.

[0164] In addition, the state where the laser light LA ​​is not diffusely reflected can be approximated to the state where the position of the light spot s1 does not change despite the movement of the reflector 522. Therefore, as the determination process S100, the control device 100 may perform a process of searching for the positional relationship between the reflector 522 and the light spot s1 such that the position of the light spot s1 does not change despite the movement of the reflector 522.

[0165] That is, the control device 100 may move the irradiation surface in a predetermined direction, and when the position of the light spot s1 determined based on the image before the movement changes, determine that the position of the light spot s1 determined does not correspond to the irradiation position. Alternatively, the control device 100 may move the irradiation surface in a predetermined direction, and when the position of the light spot s1 determined based on the image before the movement does not change, determine that the position of the light spot s1 determined corresponds to the irradiation position.

[0166] In addition, the control device 100 may move the irradiation surface in a specified direction, and further move the irradiation surface by a predetermined distance even when the position of the light spot s1 determined based on the image before the movement does not change. During the movement of the irradiation surface, the position of the light spot s1 determined based on the image is judged to be equivalent to the irradiation position based on the fact that the position of the light spot s1 determined based on the image does not change.

[0167] [Modification of the Area Where Laser Light LA ​​Avoids Passing Through]

[0168] In the above embodiment, the region D indicating the position where the laser light LA ​​is diffusely reflected is set as the avoidance region. Alternatively, the control device 100 may set a region wider than the region D as the avoidance region for the laser light LA.

[0169] As described above, when the position of the laser light source 22 is moved by driving a motor such as the drive mechanism 30, it is difficult to move the laser light source 22 in units of nm to μm. Therefore, there is a risk that even if the laser light LA ​​is moved to avoid the area D, the laser light LA ​​may pass through the area D depending on the accuracy of the drive mechanism 30.

[0170] Therefore, by setting a region wider than the region D as the region through which the laser light LA ​​avoids passing, it is possible to prevent the laser light LA ​​from passing through the region D even if the accuracy of the drive mechanism 30 is not high.

[0171] That is, when the control device 100 identifies the position of the region D, it can move the irradiation position relative to the irradiation surface so as to pass through a position at a predetermined distance from the identified position.

[0172] [Other Modifications]

[0173] (Processing implementation method)

[0174] In the above-mentioned embodiment, a structural example is shown in which the processor 120 executes a program to perform the position adjustment processing S1 of the laser light source 22 and the position adjustment processing S2 of the detector 28, but part or all of the functions provided by these processes can be installed using a dedicated hardware circuit (for example, ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array) etc.).

[0175] (Modification of the driving mechanism 30)

[0176] In the above embodiment, the drive mechanism 30 changes the irradiation position of the laser light source 22. Alternatively, the irradiation position of the laser light LA ​​may be changed by adjusting the position of the beam splitter 24. Alternatively, the cantilever 10 may be irradiated with the laser light LA ​​by moving the position of the cantilever 10.

[0177] (Modification of Adjustment Process)

[0178] In the above-mentioned embodiment, the control device 100 also performs feedback control based on the image captured by the camera unit 60 until the position of the light spot s1 is very close to the target position. In addition, the control device 100 may generate a path from the initial position of the light spot s1 to the target position in a manner avoiding the area D, and after moving the irradiation position along the generated path, perform the fine adjustment process S330. That is, before the position of the light spot s1 is very close to the target position, the control device 100 may control the drive mechanism 30 in a manner moving along the generated path, and after it is very close to the target position, perform feedback control based on the image on the drive mechanism 30. In this way, the time spent on the adjustment process can be shortened.

[0179] In addition, the control device 100 may make the distance moved in one control before the position of the light spot s1 is very close to the target position (the distance moved in S316) different from the distance moved in one control after the position of the light spot s1 is very close to the target position (the distance moved in S338).

[0180] In this case, the control device 100 may make the distance moved in S316 longer than the distance moved in S338. This can shorten the time required for the adjustment process.

[0181] That is, the control device 100 may perform the first control when the distance between the irradiation position and the cantilever is longer than the predetermined distance, and may perform the second control with higher accuracy than the first control when the distance between the irradiation position and the cantilever is closer than the predetermined distance. The first control may be, for example, a control to move the irradiation position along a path formed in a manner to avoid the area D, or may be a control to move the irradiation position in a manner to avoid the area D based on an image. The second control may also be, for example, a control to move the irradiation position based on an image.

[0182] [Way]

[0183] It will be understood by those skilled in the art that the above-described multiple exemplary embodiments are specific examples of the following aspects.

[0184] (Item 1) A scanning probe microscope according to one embodiment includes: a cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves the irradiation position of the laser light on the irradiation surface of the laser light relative to the irradiation surface; an imaging unit that includes the cantilever in an imaging range; and a control device. The control device determines a position where the laser light is diffusely reflected based on an image captured by the imaging unit, and the control device moves the irradiation position relative to the irradiation surface by the moving mechanism so as to irradiate the cantilever with the laser light in a manner that avoids the position where the laser light is diffusely reflected.

[0185] According to the scanning probe microscope described in the first aspect, since the irradiation position is adjusted to avoid the position where the laser light is diffusely reflected, it is possible to prevent the diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

[0186] (Item 2) According to the scanning probe microscope described in Item 1, the control device may determine the position at which the laser light is to be diffusely reflected based on an image captured in a state where the light source is turned off.

[0187] According to the scanning probe microscope described in the second item, since the reflected light of the laser light is not included in the image, the process of identifying the position where the laser light is diffusely reflected is simplified.

[0188] (Item 3) The scanning probe microscope according to item 1 or 2 may further include a reflector disposed on a sample holding portion for holding the sample. In this case, the control device may determine a position where the laser light is diffusely reflected within a range of an area corresponding to the reflector in an image captured by the imaging portion.

[0189] According to the scanning probe microscope described in the third aspect, since the target area for identifying the position at which the laser light is diffusely reflected is narrow, the process of identifying the position at which the laser light is diffusely reflected is simplified.

[0190] (Item 4) According to the scanning probe microscope described in any one of Items 1 to 3, when the irradiation position is relatively moved relative to the irradiation surface and the laser irradiates the cantilever, the control device may continue to move the irradiation position relative to the irradiation surface until the cantilever is no longer irradiated by the laser. In this case, the control device may determine the state of the moving mechanism when starting observation based on the state of the moving mechanism when the laser irradiates the cantilever and the state of the moving mechanism when the laser irradiates the cantilever by continuously moving the irradiation position relative to the irradiation surface.

[0191] According to the scanning probe microscope described in the fourth item, even when the adjustment accuracy of the moving mechanism for the irradiation position is not very high, the conditions for starting observation (conditions for the moving mechanism that can irradiate the cantilever with laser light) can be determined early.

[0192] (Fifth Item) A scanning probe microscope according to one embodiment includes: a cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves the irradiation position of the laser light on the irradiation surface of the laser light relative to the irradiation surface; an imaging unit that includes at least a portion of the irradiation surface in an imaging range; and a control device. Alternatively, the control device determines the position of a spot of the laser light formed on the irradiation surface based on an image captured by the imaging unit, and the control device determines the irradiation position based on whether the position of the spot of the laser light determined by the image obtained after the irradiation position is moved by the moving mechanism is a position predicted based on the movement of the irradiation position.

[0193] According to the scanning probe microscope described in the fifth item, the irradiation position of the laser light LA ​​can be determined in consideration of diffuse reflection of the laser light, thereby preventing the diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

[0194] (Item 6) According to the scanning probe microscope described in Item 5, the moving mechanism may move the irradiation position by moving the light source. In this case, the control device may move the irradiation position in a specified direction, and when the position of the light spot determined based on the image captured before the movement does not move in the specified direction, it is determined that the determined position of the light spot does not correspond to the irradiation position.

[0195] According to the scanning probe microscope described in Item 6, the irradiation position of the laser light LA ​​can be determined in consideration of diffuse reflection of the laser light, thereby preventing the diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

[0196] (Item 7) According to the scanning probe microscope described in Item 6, when the position of the light spot determined based on the image captured before the movement moves in a predetermined direction, the control device determines that the determined position of the light spot corresponds to the irradiation position.

[0197] According to the scanning probe microscope described in Item 7, the irradiation position of the laser light LA ​​can be determined in consideration of diffuse reflection of the laser light, thereby preventing the diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

[0198] (Item 8) According to the scanning probe microscope described in Item 6, it may be that, when the position of the light spot determined based on the image captured before the movement moves in a prescribed direction, the control device moves the irradiation position by a predetermined distance in the prescribed direction, and when the position of the light spot determined on the image captured by the camera unit moves in the prescribed direction in coordination with the movement of the irradiation position, the control device determines that the determined position of the light spot is equivalent to the irradiation position.

[0199] According to the scanning probe microscope described in the eighth item, it is possible to prevent the irradiation position from being wrongly determined due to the movement direction of the position of the light spot detected on the image accidentally coinciding with the actual movement direction. According to the scanning probe microscope described in the eighth item, it is also possible to ensure that the laser does not diffusely reflect over a predetermined distance for moving the irradiation position.

[0200] (Item 9) A method for adjusting the optical axis of a scanning probe microscope according to one embodiment, the scanning probe microscope comprising: a cantilever; a light source that emits a laser toward the cantilever; a moving mechanism that moves the irradiation position of the laser on the irradiation surface of the laser relative to the irradiation surface; and an imaging unit that includes the cantilever in an imaging range. The optical axis adjustment method includes the following steps: determining a position where the laser is diffusely reflected based on an image captured by the imaging unit; and moving the irradiation position relative to the irradiation surface by the moving mechanism so as to irradiate the cantilever with the laser in a manner that avoids the position where the laser is diffusely reflected.

[0201] According to the scanning probe microscope position adjustment method described in item 9, since the irradiation position is adjusted so as to avoid the position where the laser light is diffusely reflected, it is possible to prevent the diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

[0202] (Item 10) A method for adjusting the optical axis of a scanning probe microscope according to one embodiment, the scanning probe microscope comprising: a cantilever; a light source that emits a laser toward the cantilever; a moving mechanism that moves the irradiation position of the laser on the irradiation surface of the laser relative to the irradiation surface; and an imaging unit that includes at least a portion of the irradiation surface in an imaging range. The optical axis adjustment method includes the following steps: determining the position of a laser spot formed on the irradiation surface based on an image captured by the imaging unit; and determining the irradiation position based on whether the position of the laser spot determined by the image obtained after the irradiation position is moved by the moving mechanism is a position predicted based on the movement of the irradiation position.

[0203] According to the scanning probe microscope position adjustment method described in the tenth item, the irradiation position of the laser light LA ​​can be determined in consideration of diffuse reflection of the laser light, thereby preventing diffuse reflection of the laser light from adversely affecting the process of adjusting the optical axis of the laser light in the scanning probe microscope.

Claims

1. A scanning probe microscope comprising: cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves an irradiation position of the laser on the irradiation surface of the laser relative to the irradiation surface; an imaging unit that includes the cantilever in an imaging range; and Control device, in, The control device determines a position at which the laser light is diffusely reflected based on an image captured by the imaging unit while the irradiation position is moved. The control device moves the irradiation position relative to the irradiation surface by the moving mechanism so that the cantilever is irradiated with the laser beam avoiding a position where the laser beam is diffusely reflected.

2. The scanning probe microscope according to claim 1, wherein: The control device determines a position at which the laser light is diffusely reflected based on an image captured in a state in which the light source is turned off.

3. The scanning probe microscope according to claim 1, wherein: The invention further comprises a reflecting mirror provided on a sample holding portion for holding the sample. The control device determines a position at which the laser beam is to be diffusely reflected within a range of a region corresponding to the reflecting mirror in the image captured by the imaging unit.

4. The scanning probe microscope according to claim 1, wherein: When the irradiation position is moved relative to the irradiation surface and the laser beam irradiates the cantilever, the control device continues to move the irradiation position relative to the irradiation surface until the cantilever is no longer irradiated with the laser beam. The control device determines the state of the moving mechanism when starting observation based on the state of the moving mechanism when the laser irradiates the cantilever and the state of the moving mechanism when the laser no longer irradiates the cantilever by continuously moving the irradiation position relative to the irradiation surface.

5. The scanning probe microscope according to any one of claims 1 to 4, wherein: The imaging unit includes at least a portion of the irradiated surface in an imaging range; and The control device determines the position of the laser spot formed on the irradiated surface based on the image captured by the imaging unit. The control device determines the irradiation position according to whether the position of the light spot determined based on the image obtained after the irradiation position is moved by the moving mechanism is the position predicted based on the movement of the irradiation position.

6. The scanning probe microscope according to claim 5, wherein: The moving mechanism moves the irradiation position by moving the light source. The control device moves the irradiation position in a predetermined direction, and determines that the determined position of the light spot does not correspond to the irradiation position when the position of the light spot determined based on the image captured before the movement does not move in the predetermined direction.

7. The scanning probe microscope according to claim 6, wherein: When the position of the light spot determined based on the image captured before the movement moves in the predetermined direction, the control device determines that the determined position of the light spot corresponds to the irradiation position.

8. The scanning probe microscope according to claim 6, wherein: When the position of the light spot determined based on the image captured before the movement moves in the prescribed direction, the control device moves the irradiation position by a predetermined distance in the prescribed direction, When the position of the light spot identified on the image captured by the imaging unit moves in the predetermined direction in accordance with the movement of the irradiation position, the control device determines that the position of the light spot identified corresponds to the irradiation position.

9. A method for adjusting the optical axis of a scanning probe microscope. The scanning probe microscope has: cantilever; a light source that emits laser light toward the cantilever; a moving mechanism that moves an irradiation position of the laser light on an irradiation surface of the laser light relative to the irradiation surface; and a camera unit that includes the cantilever in a camera range, The optical axis adjustment method comprises the following steps: determining a position at which the laser light is diffusely reflected based on an image captured by the imaging unit while the irradiation position is moved; as well as The moving mechanism moves the irradiation position relative to the irradiation surface so that the cantilever is irradiated with the laser beam while avoiding a position where the laser beam is diffusely reflected.

10. The method for adjusting the optical axis of a scanning probe microscope according to claim 9, wherein: The imaging unit includes at least a portion of the irradiated surface in an imaging range. The optical axis adjustment method comprises the following steps: determining a position of a spot of the laser light formed on the irradiated surface based on the image captured by the imaging unit; and The irradiation position is determined based on whether the position of the light spot determined based on an image obtained after the irradiation position is moved by the moving mechanism is a position predicted based on the movement of the irradiation position.

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