Automated tip changer for an atomic force microscope and method of use thereof
By combining an XY two-dimensional electric displacement stage, an electric rotary stage, and a demagnetizing electromagnet, precise positioning and angle correction of the AFM probe are achieved, solving the problems of large space occupation of the probe box and difficulty in optical path adjustment in the prior art, and improving the efficiency and accuracy of probe replacement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN UNIV
- Filing Date
- 2023-11-10
- Publication Date
- 2026-06-26
AI Technical Summary
Existing AFM automatic needle changing devices suffer from problems such as large space occupied by probes in the probe box, difficulty in adjusting the optical path due to improper probe placement, complex operation, and low efficiency.
By combining an XY two-dimensional electric displacement stage, an electric rotary stage, a demagnetizing electromagnet, and an optical unit, and by combining rotation and translation, and using the groove wall for limiting, the probe can be precisely positioned and its angle corrected, simplifying the optical path adjustment.
It reduces the range of movement in the X and Y directions when changing needles, simplifies the optical path adjustment operation, and improves the accuracy and efficiency of needle changing.
Smart Images
Figure CN117517717B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of atomic force microscopy, and in particular to an automatic stylus changing device for an atomic force microscope and its method of use. Background Technology
[0002] Atomic force microscopes (AFM) possess sub-nanometer-level three-dimensional morphology resolution and in-situ property characterization capabilities. They also offer advantages such as good environmental adaptability and low sample preparation requirements. As one of the most common measurement instruments at the micro- and nanoscale, AFM has a wide range of applications in scientific research and advanced manufacturing.
[0003] The probe is the core sensing element of an AFM (Anaerobic Measuring Machine) and also its main consumable. Common probes are typically fabricated using microelectronic processes. Their basic structure includes a millimeter-scale rectangular silicon substrate, a microcantilever beam tens to hundreds of micrometers long located on the short side of the substrate, and a nanometer-diameter tapered tip at the free end of the microcantilever beam. During AFM operation, the tip contacts or partially contacts the sample and scans relative to it. The sample's morphology causes changes in the force on the tip, leading to bending deformation of the microcantilever beam. The sample surface morphology can be reconstructed by detecting this deformation using an optical lever method. Because the tip gradually wears down or becomes contaminated during use, it needs to be replaced periodically to maintain resolution. Furthermore, AFM often requires different types of probes when operating in different modes or testing different samples. Therefore, probe replacement is a frequent operation for AFM users.
[0004] Replacing a probe generally involves two steps. First, the unused probe is removed from the probe head, and the usable probe is loaded into the probe head. Second, the laser used to detect probe deformation is adjusted to a suitable position on the cantilever beam, and the reflected light from the cantilever beam is adjusted to a suitable position on the photodetector (PSPD). Most AFMs require manual probe replacement by the user. Due to the small size and fragility of the probes, this operation requires sufficient experience and skill. Furthermore, manual probe replacement suffers from low efficiency and poor position control accuracy. Currently, only a few AFM manufacturers equip their high-end industrial models with automatic probe replacement functionality. For example, Park System of South Korea uses magnetic automatic probe replacement technology in its NX Wafer model. In their solution, the probes are attached to dedicated metal plates, and several plates with attached probes are placed in a matrix within a probe box. When a probe replacement is needed, the XYZ 3D motor platform is first used to position the probe head at a suitable position above the probe box. Then, the electromagnet is controlled to attract the metal plate onto the probe head or drop it into the probe box. Once the metal plate with the probe is attracted to the probe head, the electric screw inside the probe head adjusts the optical path, focusing the incident laser onto the probe cantilever beam. The reflected light from the cantilever beam is then moved to the center of the PSPD, completing the entire probe replacement process. Besides the magnetic attraction method, some companies also use a vacuum adsorption method, with a similar device and process.
[0005] The above-mentioned automatic probe changing scheme has several shortcomings: 1. The probes in the probe box are arranged in a matrix. When there are many probes, the XY motor must have a larger range of movement to cover all the probes; 2. If the probe is misaligned, translation in the XY direction alone cannot correct the probe angle, and the misaligned probe angle will prevent the laser from returning to the PSPD; 3. Once the probe is attached to the probe head, its position cannot be adjusted. The incident light must be adjusted to hit the probe first, and then the reflected light must be adjusted to hit the center of the PSPD. That is, adjustment mechanisms must be set in both the incident light path and the reflected light path. Summary of the Invention
[0006] The purpose of this invention is to provide an automatic needle changing device for AFM and its usage method, so as to reduce the movement range in the X and Y directions during needle changing, correct the angle of misplaced probes, and reduce optical path adjustment operations.
[0007] To achieve the above objectives, the present invention provides the following solution:
[0008] This invention discloses an automatic needle changing device for AFM, comprising:
[0009] XY two-dimensional electric displacement stage;
[0010] An electric rotary table, mounted on the XY two-dimensional electric displacement table, is capable of moving along the X-axis and Y-axis under the drive of the XY two-dimensional electric displacement table;
[0011] The probe tray is mounted on the electric rotary table and can rotate around the Z-axis under the drive of the electric rotary table; multiple mounting slots are arranged at intervals along the circumferential direction on the probe tray.
[0012] A demagnetizing electromagnet is installed in the mounting slot and can be demagnetized after being energized; the demagnetizing electromagnet is used to attract the probe before being energized and to release the probe after being energized; the demagnetizing electromagnet is provided with a groove for placing the probe, and the groove wall is used to restrict the movement of the probe;
[0013] An electromagnet power supply unit is installed on the XY two-dimensional electric displacement stage and can move synchronously with the electric rotary table under the drive of the XY two-dimensional electric displacement stage; the electromagnet power supply unit is used to supply power to a certain demagnetized electromagnet that has rotated to the power supply position through a separable point contact method.
[0014] An optical unit includes an optical microscope and a focusing motor, the focusing motor being used to focus the optical microscope;
[0015] The AFM probe is capable of attracting the probe after the demagnetizing electromagnet is energized, and releasing the probe after the demagnetizing electromagnet is de-energized; when the AFM probe attracts and releases the probe, the distance between the AFM probe and the probe is less than or equal to a preset distance of the AFM probe.
[0016] A Z-axis electric displacement stage is mounted on the optical unit and connected to the AFM probe to drive the AFM probe to move along the Z-axis.
[0017] Preferably, the groove is in the shape of a straight line and points to the rotation axis of the probe tray.
[0018] Preferably, the bottom of the mounting groove is inclined relative to the XY plane, so that the bottom of the groove is parallel to the probe mounting surface of the AFM probe.
[0019] Preferably, the AFM probe is attracted to the probe by a permanent magnet, and the magnetism of the permanent magnet is less than that of the demagnetizing electromagnet when it is de-energized.
[0020] Preferably, the demagnetizing electromagnet has a pair of electrode contacts at its bottom, and the electromagnet power supply unit has a pair of electrode contact plates. When the pair of electrode contacts are in contact with the pair of electrode contact plates, the electromagnet power supply unit supplies DC power to the demagnetizing electromagnet.
[0021] Preferably, the plurality of mounting slots are evenly distributed along the circumference of the probe tray.
[0022] This invention also discloses a method for using an automatic probe changing device for an AFM (Automatic Microscope). The method utilizes the aforementioned automatic probe changing device to install the probe when it is not installed on the AFM probe head. Specifically, the method includes the following steps:
[0023] S1. Rotate the probe tray using the electric rotary table so that the demagnetizing electromagnet containing the probe to be replaced moves to the power supply position;
[0024] S2. Using the focusing motor, the focal plane of the optical microscope is positioned at a distance d below the probe mounting surface, and the depth of the groove is h, where d < h;
[0025] S3. Using the XY two-dimensional electric displacement stage and the Z-axis electric displacement stage, the AFM probe is positioned directly above the power supply position, and the vertical distance between the AFM probe and the bottom of the groove is H, where H>h;
[0026] S4. Use the Z-axis electric displacement stage to bring the AFM probe close to the probe tray until the optical microscope can clearly see the probe. At this time, the vertical distance between the probe and the probe mounting surface is d. If the direction of the probe deviates from the preset direction, the angle of the probe tray is finely adjusted by the electric rotary stage to make the direction of the probe consistent with the preset direction.
[0027] S5. Use the XY two-dimensional electric displacement stage to position the probe at the location of the laser focal spot in the field of view of the optical microscope.
[0028] S6. Energize the demagnetizing electromagnet located at the power supply position to demagnetize it. At this time, the probe is attracted to the bottom of the AFM probe, but does not completely detach from the groove.
[0029] S7. Using the focusing motor, the focal plane of the optical microscope is returned to the probe mounting surface, at which point the probe is clearly visible in the field of view of the optical microscope.
[0030] S8. Using the XY two-dimensional electric displacement stage, the probe tray is moved relative to the AFM probe, thereby causing the probe to slide at the bottom of the AFM probe until the cantilever beam of the probe is aligned with the laser focal spot of the optical microscope.
[0031] S9. Adjust the internal reflected light path of the AFM probe so that the reflected light hits the center of the PSPD;
[0032] S10. Using the Z-axis electric displacement stage, move the AFM probe away from the probe tray until the vertical distance between the AFM probe and the bottom of the groove is H.
[0033] S11. De-energize the demagnetizing electromagnet at the power supply position and use the XY two-dimensional electric displacement stage to position the AFM probe above the sample to be tested. This completes the entire needle replacement process.
[0034] This invention also discloses a method for using an automatic probe changing device for an AFM (Automatic Microscope). Using the aforementioned automatic probe changing device for an AFM, when the probe is mounted on the AFM probe head, the method releases the probe, specifically including the following steps:
[0035] S1. Rotate the probe tray using the electric rotary table so that the demagnetizing electromagnet, which has no probe adsorbed on its surface, reaches the power supply position.
[0036] S2. Using the focusing motor, the focal plane of the optical microscope is positioned at a distance d below the probe mounting surface, and the depth of the groove is h, where d < h;
[0037] S3. Use the XY two-dimensional electric displacement stage to position the AFM probe directly above the power supply position;
[0038] S4. Energize the demagnetizing electromagnet located at the power supply position to demagnetize it;
[0039] S5. Using the Z-axis electric displacement stage, bring the AFM probe close to the probe tray until the optical microscope can clearly see the groove on the surface of the demagnetizing electromagnet located at the power supply position. At this time, the vertical distance between the probe at the bottom of the AFM probe and the bottom of the groove is d.
[0040] S6. De-energize the demagnetizing electromagnet located at the power supply position to restore its magnetism. Since the inherent magnetism of the demagnetizing electromagnet is stronger than the magnetism of the permanent magnet of the AFM probe, the probe at the bottom of the AFM probe is attracted to the groove on the surface of the demagnetizing electromagnet located at the power supply position.
[0041] S7. Using the Z-axis electric displacement stage, move the AFM probe away from the probe tray until the vertical distance between the AFM probe and the bottom of the groove is H.
[0042] The present invention achieves the following technical effects compared to the prior art:
[0043] This invention combines translation and rotation, primarily relying on an electric rotary table and probe tray to move the probe to be installed to the designated position. The XY two-dimensional electric displacement stage can be used as an auxiliary fine-tuning structure, thereby reducing the movement range in the XY direction. Through the limiting effect of the groove wall on the probe, the angle of the misplaced probe can be corrected by the movement of the probe tray after the AFM probe has attracted the probe and before the probe has left the groove. When using this AFM automatic probe changing device, there is no need to adjust the incident light path, only the reflected light path needs to be adjusted, simplifying the operation process. Attached Figure Description
[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0045] Figure 1 This is a schematic diagram of an automatic needle-changing device for an atomic force microscope (AFM) according to an embodiment of the present invention;
[0046] Figure 2 for Figure 1 A schematic diagram of the middle section structure;
[0047] Figure 3 This is a partial structural schematic diagram of an XY two-dimensional electric displacement stage.
[0048] Figure 4 This is a schematic diagram of an electric rotary table;
[0049] Figure 5 This is a schematic diagram of the probe tray;
[0050] Figure 6 A cross-sectional view of the probe tray;
[0051] Figure 7 This is a schematic diagram of a demagnetizing electromagnet.
[0052] Explanation of reference numerals in the attached figures: 1-XY two-dimensional electric displacement stage; 2-Z-axis electric displacement stage; 3-electric rotary stage; 4-probe tray; 5-demagnetizing electromagnet; 6-electromagnet power supply unit; 7-iron sheet; 8-probe body; 9-AFM probe; 10-optical microscope; 11-focusing motor; 12-straight rod motor; 13-worm gear stepper motor. Detailed Implementation
[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0054] The purpose of this invention is to provide an automatic needle changing device for AFM and its usage method, so as to reduce the movement range in the X and Y directions during needle changing, correct the angle of misplaced probes, and reduce optical path adjustment operations.
[0055] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. In this embodiment, the extension direction of the X-axis and the extension direction of the Y-axis are generally two mutually perpendicular directions on the horizontal plane, and the Z-axis is perpendicular to the horizontal plane. In this embodiment, the probe refers to the integral structure composed of the probe body 8 and the iron sheet 7. The probe body 8 includes a rectangular silicon substrate with a millimeter scale, a microcantilever beam with a length of tens to hundreds of micrometers located on the short side of the substrate, and a tapered needle tip with a diameter of nanometers located at the free end of the microcantilever beam.
[0056] Reference Figures 1 to 7 This embodiment provides an automatic needle changing device for AFM, including an XY two-dimensional electric displacement stage 1, an electric rotary stage 3, a probe tray 4, a demagnetizing electromagnet 5, an electromagnet power supply unit 6, an optical unit, an AFM probe 9, and a Z-axis electric displacement stage 2.
[0057] The electric rotary stage 3 is mounted on the XY two-dimensional electric displacement stage 1 and can move along the X and Y axes under the drive of the XY two-dimensional electric displacement stage 1. The probe tray 4 is mounted on the central axis of the electric rotary stage 3 and can rotate around the Z axis under the drive of the electric rotary stage 3. Multiple mounting slots are arranged at intervals along the circumference of the probe tray 4. A demagnetizing electromagnet 5 is mounted in the mounting slot and can be demagnetized after being energized. The demagnetizing electromagnet 5 is used to attract probes before energization and release probes after energization. The demagnetizing electromagnet 5 has grooves for placing probes, and the groove walls are used to restrict the movement of the probes. An electromagnet power supply unit 6 is mounted on the XY two-dimensional electric displacement stage 1 and can move synchronously with the electric rotary stage 3 under the drive of the XY two-dimensional electric displacement stage 1. The electromagnet power supply unit 6 is used to supply power to a specific demagnetizing electromagnet 5 rotated to the power supply position via a separable point contact method. The optical unit includes an optical microscope 10 and a focusing motor 11, which is used to focus the optical microscope 10. The AFM probe 9 can attract the probe when the demagnetizing electromagnet 5 is energized and release the probe when the demagnetizing electromagnet 5 is de-energized. During the attraction and release of the probe by the AFM probe 9, the distance between the AFM probe 9 and the probe is less than or equal to a preset distance of the AFM probe 9, which is related to the product model of the AFM probe 9. The Z-axis electric displacement stage 2 is mounted on the optical unit and connected to the AFM probe 9, used to drive the AFM probe 9 to move along the Z-axis.
[0058] The working principle of the automatic needle changing device of this AFM is as follows:
[0059] This embodiment combines translation and rotation. It mainly relies on the electric rotary table 3 and probe tray 4 to move the probe to be installed to the designated position. The XY two-dimensional electric displacement stage 1 can be used as an auxiliary fine-tuning structure to reduce the movement range in the XY direction. By limiting the probe through the groove wall, the probe tray 4 can correct the angle of the misplaced probe after the AFM probe 9 has attracted the probe and before the probe has left the groove. When using this AFM automatic needle changing device, there is no need to adjust the incident light path, only the reflected light path needs to be adjusted, which simplifies the operation process.
[0060] As one possible example, in this embodiment, the groove is straight and points towards the rotation axis of the probe tray 4. Depending on the actual needs, those skilled in the art may also choose grooves of other shapes.
[0061] As a possible example, in this embodiment, the bottom of the mounting groove is inclined relative to the XY plane, so that the bottom of the groove is parallel to the probe mounting surface of the AFM probe 9, allowing the probe and the AFM probe 9 to fit together better.
[0062] As a possible example, in this embodiment, the AFM probe 9 uses a permanent magnet to attract the probe. The magnetism of the permanent magnet is less than that of the demagnetizing electromagnet 5 when it is de-energized, so that the unused probe can be released onto the empty demagnetizing electromagnet 5 with the groove.
[0063] As a possible example, in this embodiment, the XY two-dimensional electric displacement stage 1 is driven by a linear stepper motor 12, and the electric rotary stage 3 is driven by a worm gear stepper motor 13. Depending on the actual needs, those skilled in the art may also choose other types of drive motors.
[0064] As a possible example, in this embodiment, the demagnetizing electromagnet 5 has a pair of electrode contacts at its bottom, and the electromagnet power supply unit 6 has a pair of electrode contact plates. When the pair of electrode contacts are in contact with the pair of electrode contact plates, the electromagnet power supply unit 6 supplies DC power to the demagnetizing electromagnet 5.
[0065] As a possible example, in this embodiment, multiple mounting slots are evenly distributed along the circumference of the probe tray 4 to facilitate the calculation of the rotation angle of the electric rotary table 3.
[0066] This embodiment also provides a method for using an automatic probe changing device for an AFM. The automatic probe changing device is used to install probes when no probes are installed on the AFM probe head 9. The method includes the following steps:
[0067] S1. Use the electric rotary table 3 to rotate the probe tray 4 so that the demagnetizing electromagnet 5 where the probe to be replaced is located is in the power supply position.
[0068] S2. Using the focusing motor 11, the focal plane of the optical microscope 10 is positioned at a distance d below the probe mounting surface, with a groove depth of h, where d < h. The probe mounting surface refers to the plane where the probe cantilever beam is located when the probe is attached to the bottom of the AFM probe 9, which is also the laser focal plane in the AFM probe 9.
[0069] S3. Use the XY two-dimensional electric displacement stage 1 and the Z-axis electric displacement stage 2 to position the AFM probe 9 directly above the power supply position, and the vertical distance between the AFM probe 9 and the bottom of the groove is H, where H>h (H is generally more than twice h).
[0070] S4. Use the Z-axis electric displacement stage 2 to bring the AFM probe 9 close to the probe tray 4 until the optical microscope 10 can clearly see the probe. At this point, the vertical distance between the probe and the probe mounting surface is d. If the direction of the probe deviates from the preset direction, use the electric rotary stage 3 to finely adjust the angle of the probe tray 4 to make the direction of the probe consistent with the preset direction.
[0071] S5. Use the XY two-dimensional electric displacement stage 1 to position the probe at the location of the laser focal spot in the field of view of the optical microscope 10.
[0072] S6. Power on the demagnetizing electromagnet 5 located in the power supply position to demagnetize it. At this time, the probe is attracted to the bottom of the AFM probe 9, but it is not completely removed from the groove.
[0073] S7. Use the focusing motor 11 to return the focal plane of the optical microscope 10 to the probe mounting surface. At this time, the probe is clearly visible in the field of view of the optical microscope 10.
[0074] S8. Using the XY two-dimensional electric displacement stage 1, the probe tray 4 is moved relative to the AFM probe 9, thereby driving the probe to slide at the bottom of the AFM probe 9 until the cantilever beam of the probe is aligned with the laser focal spot of the optical microscope 10.
[0075] S9. Adjust the internal reflected light path of the AFM probe 9 so that the reflected light hits the center of the PSPD.
[0076] S10. Use the Z-axis electric displacement stage 2 to move the AFM probe 9 away from the probe tray 4, until the vertical distance between the AFM probe 9 and the bottom of the groove is H.
[0077] S11. De-energize the demagnetizing electromagnet 5 at the power supply position, and use the XY two-dimensional electric displacement stage 1 to position the AFM probe 9 above the sample to be tested. This completes the entire needle replacement process.
[0078] This embodiment also provides a method for using an automatic probe changing device for an AFM. The automatic probe changing device is used to release a probe when one is mounted on the AFM probe head 9. The method includes the following steps:
[0079] S1. Use the electric rotary table 3 to rotate the probe tray 4 so that the demagnetized electromagnet 5, which has no probes adsorbed on its surface, reaches the power supply position.
[0080] S2. Using the focusing motor 11, the focal plane of the optical microscope 10 is positioned at a distance d below the probe mounting surface, and the depth of the groove is h, where d < h.
[0081] S3. Use the XY two-dimensional electric displacement stage 1 to position the AFM probe 9 directly above the power supply position.
[0082] S4. Energize the demagnetizing electromagnet 5 located in the power supply position to demagnetize it.
[0083] S5. Use the Z-axis electric displacement stage 2 to bring the AFM probe 9 close to the probe tray 4 until the optical microscope 10 can clearly see the groove on the surface of the demagnetizing electromagnet 5 located at the power supply position. At this time, the vertical distance between the probe at the bottom of the AFM probe 9 and the bottom of the groove is d.
[0084] S6. De-energize the demagnetizing electromagnet 5 located in the power supply position to restore its magnetism. Since the inherent magnetism of the demagnetizing electromagnet 5 is stronger than the magnetism of the permanent magnet of the AFM probe 9, the probe at the bottom of the AFM probe 9 is attracted to the groove on the surface of the demagnetizing electromagnet 5 located in the power supply position.
[0085] S7. Use the Z-axis electric displacement stage 2 to move the AFM probe 9 away from the probe tray 4, until the vertical distance between the AFM probe 9 and the bottom of the groove is H.
[0086] Then, by performing steps S3 to S11 of the probe installation method described above, the installation of the probe on the AFM probe head 9 can be completed.
[0087] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.
Claims
1. A method of using an automatic needle changing device for an AFM (Automatic Needle Changer), characterized in that, An automatic needle changing device using AFM, the automatic needle changing device of AFM comprising: XY two-dimensional electric displacement stage; An electric rotary table, mounted on the XY two-dimensional electric displacement table, is capable of moving along the X-axis and Y-axis under the drive of the XY two-dimensional electric displacement table; The probe tray is mounted on the electric rotary table and can rotate around the Z-axis under the drive of the electric rotary table; multiple mounting slots are arranged at intervals along the circumferential direction on the probe tray. A demagnetizing electromagnet is installed in the mounting slot and can be demagnetized after being energized; the demagnetizing electromagnet is used to attract the probe before being energized and to release the probe after being energized; the demagnetizing electromagnet is provided with a groove for placing the probe, and the groove wall is used to restrict the movement of the probe; An electromagnet power supply unit is installed on the XY two-dimensional electric displacement stage and can move synchronously with the electric rotary table under the drive of the XY two-dimensional electric displacement stage; the electromagnet power supply unit is used to supply power to a certain demagnetized electromagnet that has rotated to the power supply position through a separable point contact method. An optical unit includes an optical microscope and a focusing motor, the focusing motor being used to focus the optical microscope; The AFM probe is capable of attracting the probe after the demagnetizing electromagnet is energized, and releasing the probe after the demagnetizing electromagnet is de-energized; when the AFM probe attracts and releases the probe, the distance between the AFM probe and the probe is less than or equal to a preset distance of the AFM probe. A Z-axis electric displacement stage is mounted on the optical unit and connected to the AFM probe to drive the AFM probe to move along the Z-axis. The automatic probe changing device of the AFM is used to install the probe when the probe is not installed on the AFM probe head, and specifically includes the following steps: S1. Rotate the probe tray using the electric rotary table so that the demagnetizing electromagnet containing the probe to be replaced moves to the power supply position; S2. Using the focusing motor, the focal plane of the optical microscope is positioned at a distance d below the probe mounting surface, and the depth of the groove is h, where d < h; S3. Using the XY two-dimensional electric displacement stage and the Z-axis electric displacement stage, the AFM probe is positioned directly above the power supply position, and the vertical distance between the AFM probe and the bottom of the groove is H, where H>h; S4. Use the Z-axis electric displacement stage to bring the AFM probe close to the probe tray until the optical microscope can clearly see the probe. At this time, the vertical distance between the probe and the probe mounting surface is d. If the direction of the probe deviates from the preset direction, the angle of the probe tray is finely adjusted by the electric rotary stage to make the direction of the probe consistent with the preset direction. S5. Use the XY two-dimensional electric displacement stage to position the probe at the location of the laser focal spot in the field of view of the optical microscope. S6. Energize the demagnetizing electromagnet located at the power supply position to demagnetize it. At this time, the probe is attracted to the bottom of the AFM probe, but does not completely detach from the groove. S7. Using the focusing motor, the focal plane of the optical microscope is returned to the probe mounting surface, at which point the probe is clearly visible in the field of view of the optical microscope. S8. Using the XY two-dimensional electric displacement stage, the probe tray is moved relative to the AFM probe, thereby causing the probe to slide at the bottom of the AFM probe until the cantilever beam of the probe is aligned with the laser focal spot of the optical microscope. S9. Adjust the internal reflected light path of the AFM probe so that the reflected light hits the center of the PSPD; S10. Using the Z-axis electric displacement stage, move the AFM probe away from the probe tray until the vertical distance between the AFM probe and the bottom of the groove is H. S11. De-energize the demagnetizing electromagnet at the power supply position and use the XY two-dimensional electric displacement stage to position the AFM probe above the sample to be tested. This completes the entire needle replacement process.
2. A method of using an automatic needle changing device for an AFM (Automatic Needle Changer), characterized in that, An automatic needle changing device using AFM, the automatic needle changing device of AFM comprising: XY two-dimensional electric displacement stage; An electric rotary table, mounted on the XY two-dimensional electric displacement table, is capable of moving along the X-axis and Y-axis under the drive of the XY two-dimensional electric displacement table; The probe tray is mounted on the electric rotary table and can rotate around the Z-axis under the drive of the electric rotary table; multiple mounting slots are arranged at intervals along the circumferential direction on the probe tray. A demagnetizing electromagnet is installed in the mounting slot and can be demagnetized after being energized; the demagnetizing electromagnet is used to attract the probe before being energized and to release the probe after being energized; the demagnetizing electromagnet is provided with a groove for placing the probe, and the groove wall is used to restrict the movement of the probe; An electromagnet power supply unit is installed on the XY two-dimensional electric displacement stage and can move synchronously with the electric rotary table under the drive of the XY two-dimensional electric displacement stage; the electromagnet power supply unit is used to supply power to a certain demagnetized electromagnet that has rotated to the power supply position through a separable point contact method. An optical unit includes an optical microscope and a focusing motor, the focusing motor being used to focus the optical microscope; The AFM probe is capable of attracting the probe after the demagnetizing electromagnet is energized, and releasing the probe after the demagnetizing electromagnet is de-energized; when the AFM probe attracts and releases the probe, the distance between the AFM probe and the probe is less than or equal to a preset distance of the AFM probe. A Z-axis electric displacement stage is mounted on the optical unit and connected to the AFM probe to drive the AFM probe to move along the Z-axis. The automatic probe changing device of the AFM is used to release the probe when the probe is installed on the AFM probe head, and specifically includes the following steps: S1. Rotate the probe tray using the electric rotary table so that the demagnetizing electromagnet, which has no probe adsorbed on its surface, reaches the power supply position. S2. Using the focusing motor, the focal plane of the optical microscope is positioned at a distance d below the probe mounting surface, and the depth of the groove is h, where d < h; S3. Use the XY two-dimensional electric displacement stage to position the AFM probe directly above the power supply position; S4. Energize the demagnetizing electromagnet located at the power supply position to demagnetize it; S5. Using the Z-axis electric displacement stage, bring the AFM probe close to the probe tray until the optical microscope can clearly see the groove on the surface of the demagnetizing electromagnet located at the power supply position. At this time, the vertical distance between the probe at the bottom of the AFM probe and the bottom of the groove is d. S6. De-energize the demagnetizing electromagnet located at the power supply position to restore its magnetism. Since the inherent magnetism of the demagnetizing electromagnet is stronger than the magnetism of the permanent magnet of the AFM probe, the probe at the bottom of the AFM probe is attracted to the groove on the surface of the demagnetizing electromagnet located at the power supply position. S7. Using the Z-axis electric displacement stage, move the AFM probe away from the probe tray until the vertical distance between the AFM probe and the bottom of the groove is H.
3. The method of using the automatic needle changing device for AFM according to claim 1 or 2, characterized in that, The groove is in the shape of a straight line and points to the rotation axis of the probe tray.
4. The method of using the automatic needle changing device of AFM according to claim 1 or 2, characterized in that, The bottom of the mounting groove is inclined relative to the XY plane, so that the bottom of the groove is parallel to the probe mounting surface of the AFM probe.
5. The method of using the automatic needle changing device for AFM according to claim 1 or 2, characterized in that, The AFM probe is attracted to the probe by a permanent magnet, and the magnetism of the permanent magnet is less than that of the demagnetizing electromagnet when it is de-energized.
6. The method of using the automatic needle changing device for AFM according to claim 1 or 2, characterized in that, The demagnetizing electromagnet has a pair of electrode contacts at its bottom, and the electromagnet power supply unit has a pair of electrode contact plates. When the pair of electrode contacts are in contact with the pair of electrode contact plates, the electromagnet power supply unit supplies power to the demagnetizing electromagnet.
7. The method of using the automatic needle changing device for AFM according to claim 1 or 2, characterized in that, The mounting slots are evenly distributed along the circumference of the probe tray.