CN113917190B

CN113917190B - Method for customizing AFM probe based on FIB equipment and atomic force microscope

Info

Publication number: CN113917190B
Application number: CN202111172714.7A
Authority: CN
Inventors: 董业民; 胡康康; 黄亚敏; 王刘勇
Original assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Current assignee: Shanghai Institute of Microsystem and Information Technology of CAS
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2023-04-07
Anticipated expiration: 2041-10-08
Also published as: CN113917190A

Abstract

The invention provides a method for customizing an AFM probe based on FIB equipment and an atomic force microscope. The method comprises the following steps: providing FIB equipment, fixing the needle tip base and the cantilever beam base on the sample table and placing the sample table and the cantilever beam base in a process chamber of the FIB equipment; cutting a needle tip with a required length from the needle tip substrate by utilizing focused ion beam etching, and etching a mounting surface at one end of the cantilever beam substrate by utilizing the focused ion beam etching; placing one end of the needle tip on the mounting surface, and fixing the one end of the needle tip and the mounting surface by utilizing focused ion beam deposition; and bombard-sharpening the needle tip by utilizing focused ion beam etching to machine the needle tip into a needle tip with a required size so as to obtain the required AFM probe. The invention provides the preparation method of the AFM probe with controllable tip height and curvature radius by using the FIB technology, the flexibility of probe preparation is greatly improved, the method can be used for customizing AFM probes with various special parameters to meet different detection requirements, and is beneficial to improving the preparation yield and reducing the preparation cost.

Description

Method for customizing AFM probe based on FIB equipment and atomic force microscope

Technical Field

The invention belongs to the field of nano manufacturing and processing, and particularly relates to a method for customizing an AFM probe based on FIB equipment and an atomic force microscope.

Background

An Atomic Force Microscope (AFM) is a high-resolution testing and characterizing instrument, and can analyze various materials and samples in the atmosphere and liquid environment, and compared with an STM (Scanning Tunneling Microscope), the AFM has the greatest advantage of detecting a non-conductive sample, and is widely applied to the fields of semiconductor (especially used for detecting various samples in an integrated circuit manufacturing process), biology, medicine research and the like.

The AFM probe consists of three important parts, namely a needle tip, a cantilever and a substrate, AFM detection is very tiny van der Waals force, and the probe is the core for realizing high-precision detection by AFM, so that the AFM has very high requirements on the appearance of the probe. In practical applications, it is desirable to select an AFM probe with suitable parameters according to the actual conditions of the sample. However, the conventional commercial probe is a substrate-cantilever-tip integrated structure processed by using semiconductor materials through processes such as etching, deposition and the like, the height and the curvature radius of the prepared tip are fixed, and the prepared probe is smaller in height and larger in curvature radius. When the probe prepared by the conventional process is used for detecting a sample with a high-aspect-ratio structure or a deep groove structure, the situation that the deep groove of the sample cannot be detected or a more detailed surface structure cannot be distinguished exists, so that the resolution ratio is low, and the detection result deviates from the actual appearance of the sample. In addition, the existing process for preparing the AFM probe needs to transfer the probe among different devices, so that the process is complex, and the probe is easily damaged. Patent application publication No. CN112180124A discloses a method for preparing a submicron probe for an atomic force microscope, which uses microsphere particles to prepare the probe, but for a sample with a large aspect ratio structure or a deeper groove structure, the tip of the microsphere is not easy to contact with the bottom of the sample, resulting in inaccurate measurement.

Disclosure of Invention

In view of the above drawbacks of the prior art, an object of the present invention is to provide a method for customizing an AFM probe based on FIB equipment and an atomic force microscope, which are used to solve the problems of the AFM probe in the prior art, such as complex process and easy damage during the preparation process, and the prepared AFM probe has a fixed tip height and a fixed radius of curvature, and the prepared probe has a small height and a large radius of curvature, and when the method is used for detecting a sample with a large aspect ratio structure or a deep trench structure, the probe cannot contact the bottom of the sample, so that the resolution is low, and the detection result deviates from the actual morphology of the sample. The invention provides a method for preparing an AFM probe with controllable tip height and curvature radius by using FIB technology, can prepare the AFM probe with self-defined parameters (namely, the customization of the AFM probe is realized), has high preparation flexibility, and can meet the detection requirements of samples with special structures such as the prior deeper groove structure and the like.

To achieve the above and other related objects, the present invention provides a method for customizing an AFM probe based on FIB equipment, comprising the steps of:

providing FIB equipment, fixing the needle tip substrate and the cantilever beam substrate on the sample table, and placing the sample table in a process chamber of the FIB equipment to ensure that the process chamber is in a vacuum state;

cutting a needle tip with a required length from the needle tip substrate by utilizing focused ion beam etching, and etching a mounting surface at one end of the cantilever beam substrate by utilizing the focused ion beam etching;

placing one end of the needle tip on the mounting surface, and fixing the one end of the needle tip and the mounting surface by utilizing focused ion beam deposition;

and bombard and sharpen the needle tip by utilizing focused ion beam etching so as to process the needle tip into a needle tip with a required size and obtain the required AFM probe.

Optionally, the needle tip base and the cantilever beam base are adhered to the sample stage with an adhesive tape.

More optionally, the adhesive tape is selected from one or more of a carbon adhesive tape, a copper adhesive tape and a silver adhesive tape.

Optionally, before one end of the cantilever beam substrate is etched to form an installation surface, the manipulator of the FIB equipment is withdrawn, and then the platinum needle is withdrawn; and after the etching of the cantilever beam substrate is finished, placing one end of the needle tip on the mounting surface by adopting a manipulator.

Optionally, the needle tip base comprises a tungsten needle, and the needle tip is cut from one end of the tungsten needle with a relatively large curvature radius; the needle tip is fixed on the mounting surface, the diameter of one end of the needle tip, which is fixed on the mounting surface, is the same as that of the mounting surface, and the diameter of the other end of the needle tip is smaller than that of the mounting surface.

Optionally, after the needle tip base and the cantilever beam base are fixed on the sample stage and placed in a vacuum chamber of the FIB device, the method further comprises the step of vacuumizing to make the process chamber vacuum and/or adjusting the sample stage to make the needle tip base in a vertical state.

Alternatively, in the process of fixing the one end of the needle tip and the mounting surface by focused ion beam deposition, deposition is performed at an initial position, a position rotated by 45 ° from the initial position, and a position rotated by 90 ° from the initial position, respectively.

Optionally, in the process of performing bombardment sharpening on the needle tip by using focused ion beam etching to process the needle tip into a needle tip with a required size to obtain a required AFM probe, the needle tip is firstly subjected to bombardment sharpening for a preset time at an initial position, then is sequentially rotated by 30 °, and is subjected to bombardment sharpening for a preset time after every 30 ° rotation until the needle tip returns to the initial position.

Optionally, in the process of cutting a needle tip with a required length from the needle tip substrate by using focused ion beam etching and etching a mounting surface at one end of the cantilever beam substrate, the power of the focused ion beam is 30KV and 2.4nA.

Optionally, in the process of fixing the end of the pin tip and the mounting surface by using focused ion beam deposition, the ion beam power is 30KV and 0.26nA.

The invention also provides an atomic force microscope, and the probe of the atomic force microscope is prepared based on the method in any scheme.

As described above, the method for customizing an AFM probe based on FIB equipment and the atomic force microscope of the present invention have the following advantages: the invention provides a preparation method of an AFM probe with controllable tip height and curvature radius by using FIB technology, the flexibility of probe preparation is greatly improved, the AFM probe can be used for customizing probes with various special parameters (including different heights, curvature radii, materials and the like), and the prepared probe can fully meet the detection requirements of experimenters on a sample with a large depth-to-width ratio structure or a deeper groove structure. The method is simple, and the preparation process is always in a FIB vacuum chamber, so that the preparation cost is reduced and the preparation yield is improved. In addition, the method has the advantages of strong repeatability and controllability, high preparation efficiency, suitability for various materials and the like.

Drawings

FIG. 1 shows a flow chart of a method for customizing an AFM probe based on FIB equipment provided by the present invention.

FIG. 2 is a schematic scanning electron microscope showing the cutting of a needle tip from a base of a needle tip in an example of the present invention.

FIG. 3 is a schematic view of a scanning electron microscope for etching a mounting surface at one end of a cantilever beam in an example of the present invention.

FIG. 4 is a schematic top view of a scanning electron microscope with a needle tip bottom attached to one end of a cantilever base according to an embodiment of the present invention.

FIG. 5 is a schematic side-view SEM of FIG. 4.

FIG. 6 is a Scanning Electron Microscope (SEM) representation of the pin tip topography prior to ion bombardment in an example of the present invention.

FIG. 7 is a schematic scanning electron microscope showing the topography of a needle tip fabricated using a conventional APT needle tip reduction method.

Fig. 8 is a schematic illustration of a focused ion beam etching process for sharpening a needle tip in accordance with an exemplary embodiment of the present invention.

FIG. 9 is a schematic scanning electron microscope showing the topography of the tip prepared in the examples of the present invention.

FIG. 10 is a schematic top view scanning electron microscope showing the AFM probe of the present invention.

Description of the element reference numerals

11. Needle tip

12. Cantilever beam base

121. Mounting surface

13. Needle tip

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. As in the detailed description of the embodiments of the present invention, the cross-sectional views illustrating the device structure are not partially enlarged in general scale for convenience of illustration, and the schematic views are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

Spatially relative terms, such as "under," "below," "lower," "below," "over," "upper," and the like, may be used herein for convenience in describing the relationship of one element or feature to another element or feature illustrated in the figures. It will be understood that these terms of spatial relationship are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features are formed in between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that the drawings provided in this embodiment are only for schematically illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings and not drawn according to the number, shape and size of the components in actual implementation, and the form, quantity and proportion of each component in actual implementation may be arbitrarily changed, and the component layout may be more complicated. In order to keep the drawings as concise as possible, not all features of a single figure may be labeled in their entirety.

The existing commercial probe is a substrate-cantilever beam-needle point integrated structure processed by using semiconductor materials through processes of etching, deposition and the like, the height and the curvature radius of the prepared needle point are fixed, and when the probe is used for detecting a sample with a large depth-to-width ratio structure or a deeper groove structure, the probe cannot contact the bottom of the sample, so that the resolution ratio is low, and the detection result deviates from the actual appearance of the sample. The inventor of the application provides an improvement scheme based on long-term research on the prior art through a large number of experiments.

Specifically, as shown in fig. 1, the present invention provides a method for customizing an AFM probe based on FIB equipment, comprising the steps of:

s1: providing a Focused Ion Beam (FIB) device, fixing the tip substrate and the cantilever substrate 12 on a sample stage and placing the sample stage in a process chamber of the FIB device, wherein in order to ensure the process yield, the step generally includes a step of vacuumizing the process chamber to make the process chamber in a vacuum state, and before fixing the tip substrate and the cantilever substrate 12 on the sample stage, the tip substrate and the cantilever substrate 12 may be cleaned and dried; in order to facilitate the next focused ion beam etching process, the tip base is usually in a vertical state (i.e. perpendicular to the horizontal plane), the cantilever base 12 is adhered to the sample stage and parallel to the surface of the sample stage, but since the step of fixing the tip base and the cantilever base is usually manually operated, it is difficult to ensure the vertical state of the tip base, the method further comprises a step of adjusting the sample stage after fixing the tip base and the cantilever base on the sample stage, for example, correcting by tilting the base of the sample stage, so as to make the tip base in a vertical state (if the tip base is in a vertical state at first, the adjusting step can be omitted);

s2: cutting a needle tip 11 with a required length (generally, the height of an AFM probe to be prepared is slightly higher) from the needle tip base by utilizing focused ion beam etching, cutting a section with a relatively smaller diameter on the needle tip base and defining the section as the needle tip, wherein the needle tip is a prototype of the needle tip, which can be specifically referred to as shown in FIG. 2, and etching a mounting surface 121 at one end of the cantilever beam base 12 (the cantilever beam base combines a cantilever and the base into a whole) by utilizing the focused ion beam etching, wherein the size of the mounting surface 121 is generally consistent with the size of an end surface with a larger size of the needle tip 11, which can be specifically referred to as shown in FIG. 3;

s3: placing one end of the pin tip 11 on the mounting surface 121, such as by inserting a robot, placing the end of the pin tip 11 with a relatively small radius of curvature on the mounting surface 121 such that the other end of the pin tip 11 with a relatively large radius of curvature (i.e., the sharper end) is vertically upward, and then fixing the one end of the pin tip 11 to the mounting surface 121 by focused ion beam deposition (as in the welding principle), as shown in fig. 4 and 5;

s4: the tip 11 is subjected to bombardment sharpening by focused ion beam etching to sharpen the tip 11 (see fig. 6) (see fig. 8) into a tip 13 (see fig. 9) of a desired size to obtain a desired AFM probe (see fig. 10).

The invention provides a preparation method of an AFM probe with controllable needle point height and curvature radius by using FIB technology, the flexibility of probe preparation is greatly improved, the AFM probe can be used for customizing various probes with special parameters (including different heights, curvature radii, materials and the like), and the prepared probe can fully meet the detection requirements of experimenters on a sample with a large depth-to-width ratio structure or a deeper groove structure. The preparation method is simple and easy to implement, and can effectively reduce the preparation cost; in the whole manufacturing process, the probe is positioned in the vacuum chamber of the FIB equipment, so that the adverse effect of the external environment on the probe can be avoided, and the preparation yield is improved. In addition, the method has the advantages of strong repeatability and controllability, high preparation efficiency, suitability for various materials and the like.

It should be noted that, since the structure and operation of the FIB device are known to those skilled in the art, the detailed processes of the focused ion beam etching and deposition are not described in the present specification.

In the embodiment, as an example, the tip base and the cantilever base 12 are adhered to the sample stage by using an adhesive tape, so that the damage to the probe can be reduced, and the probe can be easily peeled off subsequently. In a preferred example, the adhesive tape is a conductive adhesive tape, and the conductive adhesive tape is connected to the bottom of the sample (including the needle tip base and the cantilever beam base) and connected to the sample stage base (or the sample stage) at one side, so as to lead out electrons in the sample while adhering the sample, thereby preventing unwanted effects of the redundant electrons on imaging. In a further example, the adhesive tape includes one or more of, but is not limited to, a carbon adhesive tape, a copper adhesive tape and a silver adhesive tape, and the carbon adhesive tape is preferably selected because carbon particles on the carbon adhesive tape have a better hardness and can prevent the sample from being contaminated and/or damaged due to shedding and/or abrasion of substances on the adhesive tape. The needle tip substrate and the cantilever beam substrate can be fixed by adhesive tapes of the same or different materials, and particularly, the materials can be selected preferentially according to the materials, so that the materials are not limited strictly.

As an example, in step S2, the manipulator is fixed on the needle tip base by focused ion beam deposition, for example, the manipulator is fixed at a position of the tungsten needle near the needle tip 11 to be cut, and then the needle tip 11 is cut off from the tungsten needle by etching at a desired position by focused ion beam etching.

According to different situations of the needle tip base, for example, if the ready-made needle tip base with a proper size can be purchased from the market, the method of the invention can be directly adopted to cut the needle tip of the needle tip base, and the needle tip is further sharpened by using a focused ion beam after being fixed on the installation surface; if the size of the initially provided tip substrate is larger, pretreatment may be performed before the tip substrate and the cantilever beam substrate are fixed on the sample stage, for example, a step of using an APT tip ring cutting method to set the radius of the to-be-cut end of the tip substrate to be within 5 times of the radius of the required AFM probe. Actually, the inventor also tries to prepare the AFM probe by directly sharpening the tip by the APT tip ring cutting method, but the prepared AFM probe still has a relatively large tip size and a very rough surface, and the tip sharpened by the APT tip ring cutting method can be referred to fig. 7, but the ring cutting method has the characteristic of high efficiency, so that the tip substrate can be initially treated to reduce the subsequent workload, which is helpful to improve the preparation efficiency.

As an example, before one end of the cantilever beam base 12 is etched to etch a mounting surface, the manipulator of the FIB device is withdrawn first, and then the platinum needle is withdrawn to be far away from the cantilever beam base, because the platinum needle is shaken in vacuum when withdrawn, if the manipulator and the needle tip are not firmly fixed, the needle tip will fall off, so that the manipulator is withdrawn first, and such adverse effects can be avoided; after the etching of the cantilever base 12 is completed, an insertion robot places one end of the pin tip 11 on the mounting surface 121.

The material of the tip substrate is determined according to the AFM probe to be prepared. In this example, the tip base includes, but is not limited to, a tungsten needle, one end of which has a radius of curvature generally different from that of the other end, and the tip 11 is cut from the end of the tungsten needle having a relatively larger radius of curvature (i.e., a portion of the tip base with a sharp corner is cut, and the initially obtained tip resembles a conical cylindrical structure), which helps to reduce the subsequent sharpening operation. Of course, in other examples, the tip substrate may be made of other materials, which is not limited to this. As an example, the mounting surface 121 may be a solid surface, or as shown in fig. 3, may be a virtual circular mounting surface (that is, the bottom surface of the mounting surface is not supported by solid substances, and after the needle tip 11 is fixed on the mounting surface 121, the bottom surface of the needle tip 11 is the inner surface of the mounting surface 121), the partial arc surface of the circular mounting surface is the edge surface of the cantilever beam base, one end of the needle tip 11 fixed to the mounting surface 121 has the same diameter as that of the mounting surface 121, and the other end of the needle tip 11 is generally smaller than the diameter of the mounting surface and has a prototype of a needle tip.

As an example, in the process of fixing one end of the pin tip 11 and the mounting surface 121 (actually, the end surface corresponding to the mounting surface of the cantilever base, that is, the cantilever base) by focused ion beam deposition, deposition is performed at an initial position (which may be defined as required), a position rotated by 45 ° from the initial position, and a position rotated by 90 ° from the initial position, respectively. The rotation process can drive the sample platform to rotate through the horizontal rotation of the sample platform base in the same plane, and the deposition time at each position can be the same or different, but is preferably the same, so as to ensure the stable connection of the needle tip and the cantilever beam base.

As an example, in the process of performing bombardment sharpening on the needle tip 11 by using focused ion beam etching to process the needle tip into the needle tip 13 with a required size to obtain a required AFM probe, the needle tip 11 is firstly subjected to bombardment sharpening for a preset time at an initial position, then sequentially rotated by 30 °, and subjected to bombardment sharpening for a preset time after reaching a next position every 30 ° until returning to the initial position, and preferably, the deposition time at each position is the same, so that the deposition at each connecting position is uniform. Likewise, the rotation process can also be realized by the horizontal rotation of the sample stage in the same plane. The initial position of this step may be the same or different than the initial position defined in securing the needle tip to the mounting surface.

By way of example, in the process of cutting a needle tip with a required length from the needle tip base by utilizing focused ion beam etching and etching a mounting surface at one end of the cantilever beam base, the power of the focused ion beam is 30KV and 2.4nA, which is beneficial to avoiding the difficulty in accurately controlling etching precision due to too large power and avoiding the reduction of etching efficiency due to too small power.

As an example, in the process of fixing one end of the pin tip and the mounting surface by using focused ion beam deposition, the ion beam power is 30KV and 0.26nA, and the setting of the power can be both efficiency and yield.

In order to make the technical solution and advantages of the present invention more prominent, the following will be further explained by a specific embodiment. This embodiment comprises the steps of:

1. firstly, a tungsten needle (needle tip base) and a cantilever beam base 12 are stuck on a sample table by a carbon adhesive tape, put into a vacuum chamber of FIB equipment and vacuumized;

2. tilting a sample stage base of FIB equipment to a proper angle to enable a tungsten needle to be in a vertical and upward state;

3. according to the height requirement of the AFM probe to be prepared, 30KV and 2.4nA focused ion beam etching are selected at a required position, and a needle tip 11 (a prototype of a needle tip) is cut off from a tungsten needle, wherein the process is shown in figure 2;

4. for the front end of the cantilever beam substrate 12 (the subsequent end fixed with the needle tip is defined as the front end), 30KV and 2.4nA focused ion beams are selected for circular etching to obtain a circular mounting surface 121, and the diameter of an etching circle is the same as the diameter of the bottom of the cut needle tip 11 (the end fixed with the mounting surface 121 by the needle tip 11 is defined as the bottom, because the needle tip 11 is vertically fixed on the mounting surface 121 upwards in the subsequent process); this process is illustrated with reference to fig. 3;

5. inserting a manipulator of FIB equipment, adjusting the position of the manipulator to ensure that the bottom of the needle tip 11 is attached to the front end of the cantilever beam substrate 12, and depositing by using a focused ion beam of 30KV and 0.26 nA; the ion beam deposition is performed at three positions, namely, an initial position, a position rotated by 45 degrees from the initial position and a position rotated by 90 degrees from the initial position, and the process can be described by referring to fig. 4 and 5;

6. the initial needle tip 11 is not sharp (see fig. 6), and the needle tip 11 needs to be sharpened; the inventor adopts a conventional APT needle point circular cutting method to perform ' sharpening ' in the whole course of the previous experiment, the experiment effect is very poor, the obtained needle point 13' can refer to the graph shown in FIG. 7, the height of the needle point 13' is very small (less than 50 μm), the surface is uneven, the contact space between the needle point 13' and a cantilever beam at the bottom is also relatively small and limited by the limitation of an APT circular cutting process, the minimum curvature radius of the obtained needle point is still relatively large, the strength of the needle point is very poor and the needle point is easy to break; the inventor of the present application has studied out the present solution through long-term experiments, and performs sharpening by using a focused ion beam, and performs "sharpening" by sequentially rotating 30 ° after "sharpening" at an initial position (sharpening is performed every 30 ° rotation), and the process can be referred to as shown in fig. 8; the morphology of the tip 13 obtained by the improved tip "sharpening" method is shown in fig. 9, and the structure of the resulting AFM probe is shown in fig. 10. As can be seen from fig. 9 and 10, the AFM probe prepared according to the present invention has a tip 13 with a height of 94.84 μm, a tip 13 with a radius of 67.45nm, a smoother surface of the tip 13, a more uniform radius of curvature distribution, and a more stable connection with the cantilever substrate 12.

The invention also provides an atomic force microscope, and the probe of the atomic force microscope is prepared based on the method in any scheme. For the introduction of the above method, reference is also made to the foregoing contents, which are not described in detail for the sake of brevity. The detailed structure of the atomic force microscope is well known to those skilled in the art, and therefore, will not be described in detail herein. However, the atomic force microscope provided by the invention is prepared by adopting the method of the invention, so that the height and the curvature radius of the needle point can be customized according to the condition of the sample to be detected, the detection requirement of experimenters on the sample with a large depth-to-width ratio structure or a deeper groove structure can be met, and the detection precision can be improved.

In summary, the present invention provides a method for customizing an AFM probe based on FIB equipment and an atomic force microscope. The method comprises the following steps: providing FIB equipment, fixing the needle tip substrate and the cantilever beam substrate on the sample table and placing the sample table and the cantilever beam substrate in a process chamber of the FIB equipment; cutting a needle tip with a required length from the needle tip substrate by utilizing focused ion beam etching, and etching a mounting surface at one end of the cantilever beam substrate by utilizing the focused ion beam etching; placing one end of the needle tip on the mounting surface, and fixing the one end of the needle tip and the mounting surface by utilizing focused ion beam deposition; and bombard and taper the needle tip by utilizing focused ion beam etching so as to machine the needle tip into a needle tip with a required size to obtain the required AFM probe. The invention provides a preparation method of an AFM probe with controllable tip height and curvature radius by using FIB technology, the flexibility of probe preparation is greatly improved, the AFM probe can be used for customizing probes with various special parameters (including different heights, curvature radii, materials and the like), and the prepared probe can fully meet the detection requirements of experimenters on a sample with a large depth-to-width ratio structure or a deeper groove structure. The preparation method is simple and easy to implement, and can effectively reduce the preparation cost; in the whole manufacturing process, the probe is positioned in the vacuum chamber of the FIB equipment, so that the adverse effect of the external environment on the probe can be avoided, and the preparation yield is improved. In addition, the method has the advantages of strong repeatability and controllability, high preparation efficiency, suitability for various materials and the like. According to the atomic force microscope provided by the invention, the used probe is prepared by adopting the method provided by the invention, and the specification of the probe can be customized according to the characteristics of the detected sample, so that the probe can go deep into the sample for detection, and the detection precision is improved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A method for customizing an AFM probe based on FIB equipment is characterized by comprising the following steps:

providing FIB equipment, fixing the needle tip substrate and the cantilever beam substrate on the sample table and placing the sample table and the cantilever beam substrate in a process chamber of the FIB equipment;

cutting the needle tip substrate by an APT needle tip ring cutting method, then cutting a needle tip with a required length, wherein the radius of the needle tip obtained by the APT needle tip ring cutting method is n times of the radius of the needle tip obtained by etching with focused ion beams, n is a positive integer less than 5, and a mounting surface is etched at one end of the cantilever beam substrate by etching with the focused ion beams; placing one end of the needle tip on the mounting surface, and fixing one end of the needle tip and the mounting surface by utilizing focused ion beam deposition;

and bombard and taper the needle tip by utilizing focused ion beam etching so as to machine the needle tip into a needle tip with a required size to obtain the required AFM probe.

2. The method of claim 1, wherein the tip base and the cantilever base are attached to the sample stage using adhesive tape.

3. The method of claim 2, wherein the tape is selected from one or more of a carbon tape, a copper tape, and a silver tape.

4. The method of claim 1, wherein the needle tip base comprises a tungsten needle, and the needle tip is cut from an end of the tungsten needle having a relatively large radius of curvature; the needle tip is fixed on the mounting surface, the diameter of the needle tip is equal to that of the mounting surface, and the diameter of the needle tip is smaller than that of the mounting surface.

5. The method of claim 1, wherein after the tip base and the cantilever base are secured to the sample stage and positioned within a vacuum chamber of the FIB device, further comprising the step of evacuating the process chamber and/or adjusting the sample stage to place the tip base in an upright position.

6. The method of claim 1, wherein the step of fixing the one end of the pin tip and the mounting surface by focused ion beam deposition is performed at an initial position, a position rotated by 45 ° from the initial position, and a position rotated by 90 ° from the initial position, respectively.

7. The method of claim 1, wherein bombard sharpening the tip by focused ion beam lithography to produce a desired AFM probe by machining the tip to a desired size, wherein the bombard sharpening is performed at an initial position for a predetermined time, followed by 30 ° rotation in sequence, and after each 30 ° rotation for a predetermined time, the bombard sharpening is performed until the initial position is returned.

8. The method of claim 1, wherein the manipulator of the FIB device is withdrawn prior to the platinum needle being withdrawn prior to etching the one end of the cantilever substrate to etch the mounting surface; and after the etching of the cantilever beam substrate is finished, placing one end of the needle tip on the mounting surface by adopting a manipulator.

9. The method of claim 1, wherein in the process of cutting a needle tip with a required length from the needle tip base by utilizing focused ion beam etching and etching a mounting surface at one end of the cantilever beam base, the power of the focused ion beam is 30KV and 2.4nA; and in the process of fixing one end of the pin tip and the mounting surface by using focused ion beam deposition, the ion beam power is 30KV and 0.26nA.

10. An atomic force microscope, wherein the probe of the atomic force microscope is prepared based on the method according to any one of claims 1 to 9.