CN117517717A - Automatic needle changing device of atomic force microscope and using method thereof - Google Patents

Abstract

The invention discloses an automatic needle changing device of an Atomic Force Microscope (AFM) and a use method thereof. The demagnetizing electromagnet is arranged in the mounting groove of the probe tray and can demagnetize after being electrified. The demagnetizing electromagnet is used for adsorbing the probe before being electrified and releasing the probe after being electrified. The demagnetizing electromagnet is provided with a notch for placing the probe. The electromagnet power supply unit is arranged on the XY two-dimensional electric displacement table and can supply power to one demagnetizing electromagnet rotating to a power supply position. The AFM measuring head adsorbs the probe after the demagnetizing electromagnet is electrified, and releases the probe after the demagnetizing electromagnet is powered off. Compared with the prior art, the technical scheme of the invention can reduce the moving range of X, Y direction when changing the needle, correct the angle of the improperly placed probe and reduce the light path adjustment operation.

Description

Automatic needle changing device of atomic force microscope and using method thereof

Technical Field

The invention relates to the technical field of atomic force microscopes, in particular to an automatic needle changing device of an atomic force microscope and a use method thereof.

Background

The atomic force microscope (Atomic Force Microscope, AFM) has the advantages of sub-nanometer three-dimensional morphology resolution and in-situ physical property characterization capability, good environmental adaptability, low sample preparation requirement and the like, is one of the most common measuring instruments with micro-nanometer scale, and has wide application in the fields of scientific research and advanced manufacturing.

The probe is a core sensing element of the AFM and is also a main consumable of the AFM. The basic structure of the common probe is generally made by a microelectronic process and comprises a rectangular silicon substrate with millimeter scale, a micro-cantilever beam with the length of tens to hundreds of micrometers positioned at the short side of the substrate, and a conical needle tip with the tip diameter of nanometer scale positioned at the free end of the micro-cantilever beam. When the AFM works, the needle tip contacts or semi-contacts the sample and performs scanning motion relative to the sample, the appearance fluctuation of the sample enables the needle tip to change under stress, and further the micro-cantilever beam is bent and deformed, and the appearance of the sample surface can be reconstructed by detecting the deformation of the micro-cantilever beam through an optical lever method. Because the needle tip is gradually worn or polluted in the use process, the needle needs to be replaced at intervals to ensure the resolution; on the other hand, AFMs often also require the use of different types of probes when operating in different modes or when testing different samples. Therefore, the replacement is an operation that needs to be frequently performed for the user of the AFM.

Changing the probe generally involves two steps. Firstly, taking out an unused probe from a measuring head, and loading the probe to be used into the measuring head; and secondly, adjusting the laser for detecting the deformation of the probe to a proper position on the cantilever beam, and adjusting the light of the cantilever Liang Fanshe to a proper position on a photoelectric detector (PSPD). Most AFMs can only be manually changed by the user. This operation requires a user to have sufficient experience and operation skills because the probe is small in size and extremely fragile. In addition, the manual needle replacement has the defects of low efficiency, poor position control precision and the like. Only individual AFM manufacturers are currently equipped with an automatic needle change function in high-end industrial models. For example, the magnet automatic needle changing technology is adopted in the model NX Wafer of korean Park System. In this company's solution, probes are stuck to a dedicated iron sheet, and several iron sheets to which probes are stuck are placed in a probe cassette in a matrix form. When the needle needs to be replaced, the measuring head is positioned to a proper position above the probe box through the XYZ three-dimensional motor platform, and then the iron sheet is sucked onto the measuring head or falls into the probe box from the measuring head through the control of the electromagnet; after the iron sheet with the probe is adsorbed on the probe, the electric screw rod in the probe is used for adjusting the light path, so that the incident laser is focused on the cantilever beam of the probe in sequence, and the light of the cantilever Liang Fanshe is moved to the center of the PSPD, thus completing the whole needle changing process. Besides the magnetic attraction scheme, a company adopts a vacuum adsorption mode, and a needle changing device and a needle changing process are similar to those of the magnetic attraction scheme.

The automatic needle changing scheme has several defects: 1. probes in the probe box are arranged in a matrix form, and when the number of probes is large, the XY motor must have a larger moving range to cover all the probes; 2. if the probe is put askew, the probe angle cannot be corrected only by translation in the XY direction, and the laser cannot return to the PSPD due to the fact that the probe angle is not correct; 3. the probe cannot be readjusted after being adsorbed on the probe, the incident light must be adjusted to strike the probe, and then the reflected light must be adjusted to strike the center of the PSPD, i.e. the incident light path and the reflected light path must be provided with adjusting mechanisms.

Disclosure of Invention

The invention aims to provide an automatic needle changing device of an AFM and a use method thereof, which are used for reducing the moving range of X, Y direction during needle changing, correcting the angle of a probe which is not placed correctly and reducing the light path adjusting operation.

In order to achieve the above object, the present invention provides the following solutions:

the invention discloses an automatic needle changing device of an AFM, which comprises:

an XY two-dimensional electric displacement table;

the electric rotating table is arranged on the XY two-dimensional electric displacement table and can move along an X axis and a Y axis under the driving of the XY two-dimensional electric displacement table;

the probe tray is arranged on the electric rotating table and can rotate around the Z axis under the driving of the electric rotating table; a plurality of mounting grooves are arranged on the probe tray at intervals along the circumferential direction;

the demagnetizing electromagnet is arranged in the mounting groove and can demagnetize after being electrified; the demagnetizing electromagnet is used for adsorbing the probe before being electrified and releasing the probe after being electrified; the demagnetizing electromagnet is provided with a notch for placing the probe, and the groove wall of the notch is used for limiting the movement of the probe;

the electromagnet power supply unit is arranged on the XY two-dimensional electric displacement table and can synchronously move with the electric rotating table under the driving of the XY two-dimensional electric displacement table; the electromagnet power supply unit is used for supplying power to one of the demagnetizing electromagnets rotating to a power supply position in a separable point contact mode;

the optical unit comprises an optical microscope and a focusing motor, and the focusing motor is used for focusing the optical microscope;

the AFM measuring head can adsorb the probe after the demagnetizing electromagnet is electrified and release the probe after the demagnetizing electromagnet is powered off; when the action of adsorbing and releasing the probe by the AFM probe occurs, the distance between the AFM probe and the probe is smaller than or equal to the preset distance of the AFM probe;

and the Z-axis electric displacement table is arranged on the optical unit and connected with the AFM measuring head and used for driving the AFM measuring head to move along the Z axis.

Preferably, the notch is in a straight shape and is directed to the rotation axis of the probe tray.

Preferably, the groove bottom of the mounting groove is inclined with respect to the XY plane, so that the groove bottom of the notch groove and the probe mounting surface of the AFM probe are parallel to each other.

Preferably, the AFM probe adsorbs the probe through a permanent magnet, and the magnetism of the permanent magnet is smaller than that of the demagnetizing electromagnet when the demagnetizing electromagnet is powered off.

Preferably, the bottom of the demagnetizing electromagnet is provided with a pair of electrode contacts, the electromagnet power supply unit is provided with a pair of electrode contact plates, and when the pair of electrode contacts are in contact with the pair of electrode contact plates, the electromagnet power supply unit supplies direct current to the demagnetizing electromagnet.

Preferably, the plurality of mounting grooves are uniformly distributed along a circumferential direction of the probe tray.

The invention also discloses a use method of the automatic needle changing device of the AFM, which is used for installing the probe when the probe is not installed on the AFM measuring head, and specifically comprises the following steps:

s1, rotating the probe tray by using the electric rotating table to enable the demagnetizing electromagnet where the probe to be replaced is located to reach the power supply position;

s2, utilizing the focusing motor to enable the focal plane of the optical microscope to be positioned at a position with a distance d below the probe mounting surface, wherein the depth of the notch is h, and d is smaller than h;

s3, utilizing the XY two-dimensional electric displacement table and the Z-axis electric displacement table to enable the AFM measuring head to be located right above the power supply position, wherein the vertical distance between the AFM measuring head and the groove bottom of the grooving is H, and H > H;

s4, enabling the AFM measuring head to approach the probe tray by utilizing the Z-axis electric displacement table until the optical microscope can see the probe clearly, wherein 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 through the electric rotating table, so that the direction of the probe is consistent with the preset direction;

s5, utilizing the XY two-dimensional electric displacement table to enable the probe to be located at the position of a laser focal spot in the view field of the optical microscope;

s6, electrifying the demagnetizing electromagnet positioned at the power supply position to demagnetize the demagnetizing electromagnet, wherein the probe is sucked to the bottom of the AFM probe but is not completely separated from the notch;

s7, enabling a focal plane of the optical microscope to return to the probe mounting surface by utilizing the focusing motor, wherein the probe is clearly visible in a field of view of the optical microscope;

s8, utilizing the XY two-dimensional electric displacement table to enable the probe tray to move relative to the AFM measuring head, and further driving the probe to slide at the bottom of the AFM measuring head until the cantilever beam of the probe is aligned with a laser focal spot of the optical microscope;

s9, adjusting an internal reflection light path of the AFM measuring head to enable reflected light to strike the center of the PSPD;

s10, enabling the AFM measuring head to be far away from the probe tray by utilizing the Z-axis electric displacement table, wherein the vertical distance between the AFM measuring head and the groove bottom of the grooving is H;

s11, powering off the demagnetizing electromagnet at the power supply position, and enabling the AFM measuring head to be located above the sample to be measured by using the XY two-dimensional electric displacement table, so that the whole needle changing process is completed.

The invention also discloses a use method of the automatic needle changing device of the AFM, which is used for releasing the probe when the probe is arranged on the AFM measuring head, and specifically comprises the following steps:

s1, rotating the probe tray by using the electric rotating table to enable the demagnetizing electromagnet with the surface not adsorbing the probe to reach the power supply position;

s2, utilizing the focusing motor to enable the focal plane of the optical microscope to be positioned at a position with a distance d below the probe mounting surface, wherein the depth of the notch is h, and d is smaller than h;

s3, enabling the AFM measuring head to be located right above the power supply position by utilizing the XY two-dimensional electric displacement table;

s4, electrifying the demagnetizing electromagnet positioned at the power supply position to demagnetize the demagnetizing electromagnet;

s5, enabling the AFM measuring head to approach the probe tray by utilizing the Z-axis electric displacement table until the optical microscope can clearly see the notch on the surface of the demagnetizing electromagnet positioned at the power supply position, wherein the vertical distance between the probe at the bottom of the AFM measuring head and the bottom of the notch is d;

s6, the demagnetizing electromagnet positioned at the power supply position is powered off to restore magnetism, and as the inherent magnetism of the demagnetizing electromagnet is stronger than that of the permanent magnet of the AFM measuring head, the probe at the bottom of the AFM measuring head is sucked into the notch on the surface of the demagnetizing electromagnet positioned at the power supply position;

s7, enabling the AFM measuring head to be far away from the probe tray by utilizing the Z-axis electric displacement table, and enabling the vertical distance between the AFM measuring head and the groove bottom of the grooving to be H.

Compared with the prior art, the invention has the following technical effects:

according to the invention, translation and rotation are combined, the probes to be installed are moved to the designated positions mainly by virtue of the electric rotating table and the probe tray, and the XY two-dimensional electric displacement table can be used as an auxiliary fine adjustment structure, so that the moving range of the XY direction is reduced; through the limiting effect of the groove wall of the groove on the probe, after the AFM probe adsorbs the probe and the probe does not leave the groove, the angle correction can be carried out on the improperly placed probe through the action of the probe tray; when the automatic needle changing device of the AFM is used, an incident light path is not required to be regulated, and only a reflecting light path is required to be regulated, so that the operation process is simplified.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an automatic needle changing device of an Atomic Force Microscope (AFM) according to an embodiment of the invention;

FIG. 2 is a schematic diagram of a portion of the structure of FIG. 1;

FIG. 3 is a schematic view of a part of the structure of an XY two-dimensional electric displacement table;

FIG. 4 is a schematic view of an electric turntable;

FIG. 5 is a schematic view of a probe tray;

FIG. 6 is a cross-sectional view of a probe tray;

FIG. 7 is a schematic diagram of a demagnetizing electromagnet;

reference numerals illustrate: 1-XY two-dimensional electric displacement table; 2-Z axis electric displacement table; 3-an electric rotating table; 4-a probe tray; 5-demagnetizing electromagnet; 6-an electromagnet power supply unit; 7-iron sheets; 8-a probe body; 9-AFM gauge head; 10-optical microscope; 11-focusing motor; 12-a straight rod motor; 13-worm gear type stepping motor.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The invention aims to provide an automatic needle changing device of an AFM and a use method thereof, which are used for reducing the moving range of X, Y direction during needle changing, correcting the angle of a probe which is not placed correctly and reducing the light path adjusting operation.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. In this embodiment, the extending direction of the X axis and the extending direction of the Y axis are generally two directions perpendicular to each other on a horizontal plane, and the Z axis is perpendicular to the horizontal plane. In this embodiment, the probe is an integral structure formed by a probe body 8 and an iron sheet 7, wherein the probe body 8 comprises a rectangular silicon substrate with a millimeter scale, a micro-cantilever with a length of tens to hundreds of micrometers positioned at the short side of the substrate, and a tapered tip with a tip diameter of nanometer scale positioned at the free end of the micro-cantilever.

Referring to fig. 1 to 7, the present embodiment provides an automatic needle changing device of an AFM, which includes an XY two-dimensional electric displacement table 1, an electric rotary table 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 table 2.

The electric rotating table 3 is mounted on the XY two-dimensional electric displacement table 1, and is movable along the X axis and the Y axis by the driving of the XY two-dimensional electric displacement table 1. The probe tray 4 is mounted on the center axis of the electric turntable 3, and is rotatable about the Z axis by the electric turntable 3. A plurality of mounting grooves are arranged on the probe tray 4 at intervals in the circumferential direction. The demagnetizing electromagnet 5 is installed in the installation groove, and can demagnetize after being electrified. The demagnetizing electromagnet 5 is used for adsorbing the probe before being electrified and releasing the probe after being electrified. The demagnetizing electromagnet 5 is provided with a notch for placing the probe, and the wall of the notch is used for limiting the movement of the probe. The electromagnet power supply unit 6 is mounted on the XY two-dimensional electric displacement table 1, and can move synchronously with the electric rotary table 3 under the drive of the XY two-dimensional electric displacement table 1. The electromagnet power supply unit 6 is used for supplying power to one demagnetizing electromagnet 5 which rotates to a power supply position in a separable point contact mode. The optical unit includes an optical microscope 10 and a focusing motor 11, and the focusing motor 11 is used for focusing the optical microscope 10. The AFM probe 9 can attract the probe after the demagnetizing electromagnet 5 is electrified and release the probe after the demagnetizing electromagnet 5 is powered off. When the action of the AFM probe 9 for adsorbing and releasing the probe occurs, the distance between the AFM probe 9 and the probe is smaller than or equal to the preset distance of the AFM probe 9, and the preset distance is related to the product model of the AFM probe 9. The Z-axis electric displacement table 2 is arranged on the optical unit and connected with the AFM measuring head 9, and is used for driving the AFM measuring head 9 to move along the Z axis.

The working principle of the automatic needle changing device of the AFM is as follows:

in the embodiment, the translation and the rotation are combined, the probes to be installed are moved to the designated positions mainly by virtue of the electric rotating table 3 and the probe tray 4, and the XY two-dimensional electric displacement table 1 can be used as an auxiliary fine adjustment structure, so that the moving range of the XY direction is reduced; after the AFM probe 9 adsorbs the probe and the probe does not leave the notch, the probe with improper placement can be subjected to angle correction by the action of the probe tray 4 through the limiting action of the notch wall on the probe; when the automatic needle changing device of the AFM is used, an incident light path is not required to be regulated, and only a reflecting light path is required to be regulated, so that the operation process is simplified.

As a possible example, in this embodiment the score groove is in the form of a straight line and is directed towards the axis of rotation of the probe tray 4. Other shapes of grooves may be selected by those skilled in the art depending on the actual needs.

As a possible example, in the present embodiment, the groove bottom of the mounting groove is inclined with respect to the XY plane, so that the groove bottom of the notch groove and the probe mounting surface of the AFM probe 9 are parallel to each other, and the probe and the AFM probe 9 can be bonded better.

As a possible example, in this embodiment, the AFM probe 9 attracts the probe through the permanent magnet, and the magnetism of the permanent magnet is smaller than that of the demagnetizing electromagnet 5 when the power is off, so as to release the unused probe onto the demagnetizing electromagnet 5 with the notch being empty.

As a possible example, in the present embodiment, the XY two-dimensional electric displacement stage 1 is driven using a straight-bar type stepping motor 12, and the electric rotary stage 3 is driven using a worm wheel type stepping motor 13. Other forms of drive motors may be selected by those skilled in the art as desired.

As a possible example, in the present embodiment, the bottom of the demagnetizing electromagnet 5 has a pair of electrode contacts, the electromagnet power supply unit 6 has a pair of electrode contact plates, and when the pair of electrode contacts are in contact with the pair of electrode contact plates, the electromagnet power supply unit 6 supplies direct current to the demagnetizing electromagnet 5.

As a possible example, in the present embodiment, a plurality of mounting grooves are uniformly distributed along the circumferential direction of the probe tray 4 to facilitate calculation of the rotation angle of the electric rotating table 3.

The embodiment also provides a method for using the automatic pin changing device of the AFM, which is used for installing the probe when the probe is not installed on the AFM probe 9, and specifically comprises the following steps:

s1, rotating the probe tray 4 by utilizing the electric rotating table 3 to enable the demagnetizing electromagnet 5 where the probe to be replaced is located to reach a power supply position.

S2, a focusing motor 11 is used for enabling the focal plane of the optical microscope 10 to be located at a position with a distance d below the probe mounting surface, and the depth of the notch is h, and d is smaller than h. The probe mounting surface refers to the plane in which the cantilever beam of the probe is positioned when the probe is adsorbed at the bottom of the AFM probe 9, and is also the laser focal plane in the AFM probe 9.

S3, the XY two-dimensional electric displacement table 1 and the Z-axis electric displacement table 2 are utilized to enable the AFM measuring head 9 to be located right above the power supply position, and the vertical distance between the AFM measuring head 9 and the groove bottom of the notch groove is H, wherein H > H (H is generally more than 2 times of H).

S4, the Z-axis electric displacement table 2 is utilized to enable the AFM measuring head 9 to be close to the probe tray 4 until the optical microscope 10 can see the probe clearly, and 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 4 is finely adjusted by the electric rotating table 3 so that the direction of the probe is consistent with the preset direction.

S5, the XY two-dimensional electric displacement table 1 is utilized to enable the probe to be located at the position of the laser focal spot in the view field of the optical microscope 10.

S6, electrifying the demagnetizing electromagnet 5 positioned at the power supply position to demagnetize the demagnetizing electromagnet, wherein the probe is sucked to the bottom of the AFM measuring head 9, but is not completely separated from the notch.

S7, the focal plane of the optical microscope 10 is returned to the probe mounting surface by utilizing the focusing motor 11, and at the moment, the probe is clearly visible in the field of view of the optical microscope 10.

And S8, utilizing the XY two-dimensional electric displacement table 1 to enable the probe tray 4 to move relative to the AFM measuring head 9, and further driving the probe to slide at the bottom of the AFM measuring head 9 until the cantilever beam of the probe is aligned with the laser focal spot of the optical microscope 10.

S9, adjusting an internal reflection light path of the AFM measuring head 9 to enable reflected light to hit the center of the PSPD.

S10, the Z-axis electric displacement table 2 is used for enabling the AFM measuring head 9 to be far away from the probe tray 4, and the vertical distance between the AFM measuring head 9 and the groove bottom of the notch groove is H.

S11, powering off the demagnetizing electromagnet 5 at the power supply position, and using the XY two-dimensional electric displacement table 1 to enable the AFM measuring head 9 to be located above the sample to be measured, so that the whole needle changing process is completed.

The embodiment also provides a method for using the automatic pin changing device of the AFM, which is used for releasing the probe when the probe is installed on the AFM probe 9, and specifically comprises the following steps:

s1, rotating the probe tray 4 by using the electric rotating table 3, so that the demagnetizing electromagnet 5 with no probe adsorbed on the surface reaches a power supply position.

S2, a focusing motor 11 is used for enabling the focal plane of the optical microscope 10 to be located at a position with a distance d below the probe mounting surface, and the depth of the notch is h, and d is smaller than h.

S3, the AFM measuring head 9 is positioned right above the power supply position by using the XY two-dimensional electric displacement table 1.

S4, electrifying the demagnetizing electromagnet 5 positioned at the power supply position to demagnetize the demagnetizing electromagnet.

S5, the Z-axis electric displacement table 2 is utilized to enable the AFM measuring head 9 to be close to the probe tray 4 until the optical microscope 10 can clearly see the engraved groove on the surface of the demagnetizing electromagnet 5 positioned at the power supply position, and at the moment, the vertical distance between the probe at the bottom of the AFM measuring head 9 and the bottom of the engraved groove is d.

S6, the demagnetizing electromagnet 5 positioned at the power supply position is powered off to restore magnetism, and as the inherent magnetism of the demagnetizing electromagnet 5 is stronger than the magnetism of the permanent magnet of the AFM measuring head 9, a probe at the bottom of the AFM measuring head 9 is sucked into a notch on the surface of the demagnetizing electromagnet 5 positioned at the power supply position.

S7, the Z-axis electric displacement table 2 is utilized to enable the AFM measuring head 9 to be far away from the probe tray 4, and the vertical distance between the AFM measuring head 9 and the groove bottom of the notch groove is H.

Thereafter, the steps S3 to S11 of the probe mounting method are performed, and the mounting of the probe on the AFM probe 9 can be completed.

The principles and embodiments of the present invention have been described in this specification with reference to specific examples, the description of which is only for the purpose of aiding in understanding the method of the present invention and its core ideas; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.

Claims (8)

1. An automatic needle changing device of an AFM, comprising:

an XY two-dimensional electric displacement table;

the electric rotating table is arranged on the XY two-dimensional electric displacement table and can move along an X axis and a Y axis under the driving of the XY two-dimensional electric displacement table;

the probe tray is arranged on the electric rotating table and can rotate around the Z axis under the driving of the electric rotating table; a plurality of mounting grooves are arranged on the probe tray at intervals along the circumferential direction;

the demagnetizing electromagnet is arranged in the mounting groove and can demagnetize after being electrified; the demagnetizing electromagnet is used for adsorbing the probe before being electrified and releasing the probe after being electrified; the demagnetizing electromagnet is provided with a notch for placing the probe, and the groove wall of the notch is used for limiting the movement of the probe;

the electromagnet power supply unit is arranged on the XY two-dimensional electric displacement table and can synchronously move with the electric rotating table under the driving of the XY two-dimensional electric displacement table; the electromagnet power supply unit is used for supplying power to one of the demagnetizing electromagnets rotating to a power supply position in a separable point contact mode;

the optical unit comprises an optical microscope and a focusing motor, and the focusing motor is used for focusing the optical microscope;

the AFM measuring head can adsorb the probe after the demagnetizing electromagnet is electrified and release the probe after the demagnetizing electromagnet is powered off; when the action of adsorbing and releasing the probe by the AFM probe occurs, the distance between the AFM probe and the probe is smaller than or equal to the preset distance of the AFM probe;

and the Z-axis electric displacement table is arranged on the optical unit and connected with the AFM measuring head and used for driving the AFM measuring head to move along the Z axis.

2. The automatic needle changing device of an AFM according to claim 1, wherein the notch is in a straight shape and is directed to the rotation axis of the probe tray.

3. The automatic pin changing device of an AFM according to claim 1, wherein a bottom of the mounting groove is inclined with respect to an XY plane so that the bottom of the notch groove and a probe mounting surface of the AFM probe are parallel to each other.

4. The automatic pin changing device of an AFM according to claim 1, wherein the AFM probe adsorbs the probe by a permanent magnet having a magnetic property smaller than that of the demagnetizing electromagnet when the demagnetizing electromagnet is powered off.

5. The automatic pin changing device of an AFM according to claim 1, wherein the bottom of the demagnetizing electromagnet has a pair of electrode contacts, the electromagnet power supply unit has a pair of electrode contacts, and the electromagnet power supply unit supplies power to the demagnetizing electromagnet when the pair of electrode contacts are in contact with the pair of electrode contacts.

6. The automatic pin changing device of an AFM according to claim 1, wherein the plurality of mounting grooves are uniformly distributed along a circumferential direction of the probe tray.

7. A method of using the automatic pin changing device of an AFM according to any one of claims 1 to 6, wherein the automatic pin changing device of an AFM is used for installing the probe when the probe is not installed on the AFM probe, and the method specifically comprises the steps of:

s1, rotating the probe tray by using the electric rotating table to enable the demagnetizing electromagnet where the probe to be replaced is located to reach the power supply position;

s2, utilizing the focusing motor to enable the focal plane of the optical microscope to be positioned at a position with a distance d below the probe mounting surface, wherein the depth of the notch is h, and d is smaller than h;

s3, utilizing the XY two-dimensional electric displacement table and the Z-axis electric displacement table to enable the AFM measuring head to be located right above the power supply position, wherein the vertical distance between the AFM measuring head and the groove bottom of the grooving is H, and H > H;

s4, enabling the AFM measuring head to approach the probe tray by utilizing the Z-axis electric displacement table until the optical microscope can see the probe clearly, wherein 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 through the electric rotating table, so that the direction of the probe is consistent with the preset direction;

s5, utilizing the XY two-dimensional electric displacement table to enable the probe to be located at the position of a laser focal spot in the view field of the optical microscope;

s6, electrifying the demagnetizing electromagnet positioned at the power supply position to demagnetize the demagnetizing electromagnet, wherein the probe is sucked to the bottom of the AFM probe but is not completely separated from the notch;

s7, enabling a focal plane of the optical microscope to return to the probe mounting surface by utilizing the focusing motor, wherein the probe is clearly visible in a field of view of the optical microscope;

s8, utilizing the XY two-dimensional electric displacement table to enable the probe tray to move relative to the AFM measuring head, and further driving the probe to slide at the bottom of the AFM measuring head until the cantilever beam of the probe is aligned with a laser focal spot of the optical microscope;

s9, adjusting an internal reflection light path of the AFM measuring head to enable reflected light to strike the center of the PSPD;

s10, enabling the AFM measuring head to be far away from the probe tray by utilizing the Z-axis electric displacement table, wherein the vertical distance between the AFM measuring head and the groove bottom of the grooving is H;

s11, powering off the demagnetizing electromagnet at the power supply position, and enabling the AFM measuring head to be located above the sample to be measured by using the XY two-dimensional electric displacement table, so that the whole needle changing process is completed.

8. A method for using the automatic pin changing device of the AFM, characterized in that the automatic pin changing device of the AFM according to any one of claims 1 to 6 is used for releasing the probe when the probe is mounted on the AFM probe, and the method specifically comprises the following steps:

s1, rotating the probe tray by using the electric rotating table to enable the demagnetizing electromagnet with the surface not adsorbing the probe to reach the power supply position;

s2, utilizing the focusing motor to enable the focal plane of the optical microscope to be positioned at a position with a distance d below the probe mounting surface, wherein the depth of the notch is h, and d is smaller than h;

s3, enabling the AFM measuring head to be located right above the power supply position by utilizing the XY two-dimensional electric displacement table;

s4, electrifying the demagnetizing electromagnet positioned at the power supply position to demagnetize the demagnetizing electromagnet;

s5, enabling the AFM measuring head to approach the probe tray by utilizing the Z-axis electric displacement table until the optical microscope can clearly see the notch on the surface of the demagnetizing electromagnet positioned at the power supply position, wherein the vertical distance between the probe at the bottom of the AFM measuring head and the bottom of the notch is d;

s6, the demagnetizing electromagnet positioned at the power supply position is powered off to restore magnetism, and as the inherent magnetism of the demagnetizing electromagnet is stronger than that of the permanent magnet of the AFM measuring head, the probe at the bottom of the AFM measuring head is sucked into the notch on the surface of the demagnetizing electromagnet positioned at the power supply position;

s7, enabling the AFM measuring head to be far away from the probe tray by utilizing the Z-axis electric displacement table, and enabling the vertical distance between the AFM measuring head and the groove bottom of the grooving to be H.