CN116593266A - Method for preparing nano mechanical test sample by utilizing focused ion beam - Google Patents

Abstract

The invention relates to the technical field of nanomechanical testing, in particular to a method for preparing a nanomechanical test sample by using a focused ion beam, which includes the following steps: using a focused ion beam to extract a sample precursor from a region to be tested, the sample The precursor meets the following requirements: 1) having opposite first and second surfaces; and 2) the surface area of the first surface is 100 μm ² to 2500 μm ² ; the second surface is fixed on the sample holding device, Adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam bombards the first surface at an incident angle of 86°-94° to complete polishing and prepare a sample for nanomechanical testing. The samples prepared by the method of the invention can be used for nanomechanical testing.

Description

Method for preparing nanomechanical test sample by using focused ion beam

technical field

The invention relates to the technical field of nanomechanical testing, in particular to a method for preparing samples for nanomechanical testing by using focused ion beams.

Background technique

Nanomechanical testing is a key technical means to obtain the mechanical properties of materials at the micro-nano scale. Among them, the nano-indentation instrument is widely used in the testing of mechanical properties (such as hardness, plasticity, Toughness, elastic modulus, fatigue properties, etc.).

Since the nanomechanical test of the micro-nano-scale region of the material is carried out on the micro-nano scale, compared with the traditional mechanical test, it has extremely high precision requirements, and it is very difficult to prepare samples suitable for nanomechanical tests. .

Contents of the invention

Based on this, the present invention provides a kind of method utilizing focused ion beam to prepare nanomechanical test sample, and its technical scheme is as follows:

A method for preparing a nanomechanical test sample by using a focused ion beam, comprising the following steps:

Using a focused ion beam to extract a sample precursor in a region to be measured of the object to be measured, the sample precursor meets the following requirements: 1) having opposite first and second surfaces; and 2) the area of the first surface 100μm ² ~ 2500μm ² ;

Fixing the second surface on the sample carrying device, adjusting the position of the sample carrying device and/or the emission angle of the focused ion beam, so that the focused ion beam bombards the first surface at an incident angle of 86°-94° , to complete the polishing and prepare samples for nanomechanical testing.

In some of these embodiments, the polishing includes a first polishing and a second polishing;

The first polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam first bombards the first surface at an incident angle of 88°-92°;

The second polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam second bombards the first surface at an incident angle of 86°-94°.

In some of these embodiments, the ion beam voltage for the first bombardment is 20kV-30kV, and the ion beam current is 1.5nA-12nA; and/or the ion beam voltage for the second bombardment is 20kV-30kV, and the ion beam current is 80pA ~ 1.5nA.

In some of the embodiments, the distance between the first surface and the second surface is 10 μm˜50 μm.

In some of these embodiments, the method for extracting a sample precursor from a region to be measured of the object to be measured by using a focused ion beam includes the following steps:

According to the requirements for the sample precursor, determine the area to be detected of the object to be detected, use a focused ion beam to pre-cut the material in the area to be detected and the material in the surrounding area, and use an extraction device to connect the area to be detected Substance, using a focused ion beam to completely cut the substance in the region to be detected and the substance in the surrounding region to obtain the sample precursor.

In some of these embodiments, pre-cutting the substance in the region to be detected and the substance in the surrounding region includes the following steps:

Retaining the connection between a part of the side of the substance in the area to be detected and the substance in the surrounding area, and cutting the remaining side and the substance in the surrounding area;

cutting the bottom of the substance in the region to be detected from the substance in the surrounding region;

Cutting the side of the area to be detected that is connected to the material in the surrounding area and the material in the surrounding area, and retaining the connection between the material in the area to be detected and the material in the surrounding area.

In some of the embodiments, the distance to be cut between the bottom edge on one side of the material bottom of the region to be detected and the bottom edge on the opposite side is greater than 20 μm.

In some of these embodiments, cutting the bottom of the substance in the area to be detected and the substance in the surrounding area includes the following steps:

Taking the bottom edge of one side of the material in the area to be detected as the starting line, after cutting from outside to inside to half the distance to be cut for the first time, taking the opposite bottom edge of the other side as the starting line, the second time Cutting from outside to inside until completely cutting off the connection between the bottom of the material in the area to be detected and the material in the surrounding area.

In some of these embodiments, the cutting planes of the first outside-in cutting and the second outside-in cutting are the same or intersect.

In some of these embodiments, the analyte satisfies one or more of the following conditions:

1) is granular; and 2) is an amorphous material.

In some of these embodiments, after polishing, the following steps are also included:

A microcolumn is processed on the first surface by using a focused ion beam for microcolumn compression testing.

Compared with traditional solutions, the present invention has the following beneficial effects:

In the present invention, a sample precursor with a large first surface area is firstly prepared, and then the focused ion beam is used to bombard the first surface to complete polishing. In this process, the positional relationship between the first surface and the focused ion beam is particularly adjusted , through the research of the present invention, it is found that: when the focused ion beam bombards the first surface at an incident angle of 86° to 94°, it has the effect of polishing a large-area first surface, and the polished first surface can satisfy For higher flatness requirements of nanomechanical testing, microcolumn compression testing and nanoindentation testing can be performed here to complete nanomechanical testing. The preparation method of the nanomechanical test sample of the present invention is suitable for amorphous particle test objects with complex structures and relatively large component differences, and provides an effective method for the nanomechanical test of such substances.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, and to understand the present invention and its beneficial effects more completely, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Apparently, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative efforts.

Fig. 1 is the actual operation diagram and schematic diagram of how to adjust the position of the sample carrying device;

Fig. 2 is the scanning electron microscope image of lunar soil particle sample in embodiment 1;

Fig. 3 is the side view image of the material in the area to be tested after pre-cutting in Example 1;

Fig. 4 is the top view image of the material in the area to be measured after pre-cutting in Example 1;

Fig. 5 is the image that the sample precursor is lifted by the nano manipulator in embodiment 1;

6 is an image of the sample precursor transferred to the M-shaped claw of the FIB special support net by the nanomanipulator in Example 1;

Fig. 7 is the side view image of the sample of nanomechanical test in embodiment 1;

Fig. 8 is the front view image of the sample of nanomechanical test in embodiment 1;

Fig. 9 is the front view image of the sample after the nanoindentation test in Example 1;

Fig. 10 is the sample front view image before and after the microcolumn compression test of experimental group in embodiment 2;

Fig. 11 is the front view images of the sample before and after the microcolumn compression test of the control group in Example 2.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples. The present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

the term

Unless otherwise stated or contradictory, terms and phrases used herein have the following meanings:

In the present invention, "optionally", "optionally" and "optionally" refer to optional, that is to say, any one selected from the two parallel schemes of "yes" or "none". If there are multiple "optional" in a technical solution, unless otherwise specified, and there is no contradiction or mutual restriction relationship, each "optional" is independent.

In the present invention, references to "further", "further" and "particularly" are used for the purpose of description, indicating differences in content, but should not be construed as limiting the protection scope of the present invention.

In the present invention, the technical features described in open form include closed technical solutions consisting of the enumerated features, as well as open technical solutions including the enumerated features.

In the present invention, when it comes to a numerical interval (that is, a numerical range), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes two numerical endpoints of the numerical range (i.e. the minimum value and the maximum value). value), and every numeric value between those two numeric endpoints. Unless otherwise specified, when the numerical range refers only to the integers within the numerical range, including the integers at the two endpoints of the numerical range, and every integer between the two endpoints, in this article, it is equivalent to directly enumerating each An integer, such as t being an integer selected from 1 to 10, means that t is any integer selected from the integer group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. Furthermore, when multiple ranges are provided to describe a feature or characteristic, these ranges may be combined. In other words, unless otherwise indicated, ranges disclosed herein are to be understood to include any and all subranges subsumed therein.

In the present invention, the incident angle refers to the angle between the beam current of the focused ion beam and the normal line of the first surface when the focused ion beam bombards the first surface.

Nanomechanical tests to characterize the mechanical properties of micro-nano-scale regions of materials can be carried out by referring to the following two methods according to different purposes:

The first method is to process micro-columns of a certain size from the micro-nano-scale region of the material, conduct a micro-column compression test, and obtain indicators such as compressive strength, plastic deformation performance, and shear strength through the compressive stress-strain curve.

The second method is to finely grind or polish the micro-nano-scale regions of the material, and conduct nano-indentation tests to obtain indicators such as hardness, Young's modulus, plastic work, and fracture toughness.

The micro-column compression test requires that the outer surface of the micro-column processed in the micro-nano-scale area of the material is smooth and smooth, and there is no obvious crack or damage at the bottom of the micro-column, so as to avoid premature plastic deformation or fracture of the micro-column during the compression test, and obtain abnormal results; nano-indentation test The micro-nano-scale area of the material is required to be finely ground or polished before the test. The purpose is to eliminate the influence of surface roughness on the nano-indentation test results and reduce the discreteness of the test results. The above puts forward high precision requirements for the preparation of samples for nanomechanical testing.

Focused ion beam is a micro-nano processing system that uses electromagnetic lenses to focus ion beams into extremely small sizes and has micro-cutting capabilities. Currently, the cutting accuracy of focused ion beams can reach 4nm. When the focused ion beam bombards the sample, its high-density energy will be transferred to the atoms and molecules in the sample, and the sample will be cut by high-energy sputtering.

One embodiment of the present invention provides a method for preparing a nanomechanical test sample using a focused ion beam, comprising the following steps:

Using a focused ion beam to extract a sample precursor in the region to be measured of the object to be measured, the sample precursor meets the following requirements: 1) having opposite first and second surfaces; and 2) the surface area of the first surface 100μm ² ~ 2500μm ² ;

Fixing the second surface on the sample carrying device, adjusting the position of the sample carrying device and/or the emission angle of the focused ion beam, so that the focused ion beam bombards the first surface at an incident angle of 86°-94° , to complete the polishing and prepare samples for nanomechanical testing.

In this embodiment, a sample precursor with a large first surface area is prepared first, and then the first surface is bombarded with a focused ion beam to complete polishing. In this process, the positions of the first surface and the focused ion beam are particularly adjusted relationship, through the research of the present invention, it is found that: when the focused ion beam bombards the first surface with an incident angle of 86° to 94°, it has the effect of polishing the large-area first surface, and the polished first surface can be To meet the higher flatness requirements of nanomechanical testing, microcolumn compression testing and nanoindentation testing can be performed here to complete nanomechanical testing. The preparation method of the nanomechanical test sample of the present invention is suitable for amorphous particle test objects with complex structures and relatively large component differences, and provides an effective method for nanomechanical test of such substances.

It can be understood that the surface area of the first surface is any value in the range of any two numerical endpoint values inclusive of the two numerical endpoint values among 100 μm ² , 500 μm ² , 1000 μm ² , 1500 μm ² , 2000 μm ² and 2500 μm ² .

Optionally, the analyte is in granular form. Further optionally, the particle size of the granular analyte is 20 μm˜90 μm. Understandably, the analyte may be spherical particles, ellipsoidal particles, polyhedral particles or other regular or irregular particles.

For micron-sized particles, it is generally difficult to prepare samples for microcolumn compression tests, because microcolumn compression tests need to process microcolumns of a certain size, which is greatly affected by the shape of the test object, especially the arc at the bottom of the particle. The shape of the surface seriously affects the test accuracy and stability; generally speaking, it is difficult to prepare samples for nanoindentation testing, because it is difficult for particles to obtain a flat surface through conventional grinding and polishing. Therefore, for the analytes with micron-sized particles, there is currently a lack of an effective method for obtaining samples for nanomechanical testing. However, through the method of this embodiment, the cubic sample precursor is obtained by cutting the particles with the focused ion beam, and then the positional relationship between the focused ion beam and the surface to be tested is adjusted, and the surface to be tested is polished by the bombardment of the focused ion beam to prepare a It is suitable for microcolumn compression test and nanoindentation test samples for nanomechanical testing.

Optionally, the distance between the first surface and the second surface is 10 μm˜50 μm. That is, the column length of the microcolumn can reach 40 μm.

Optionally, the analyte is an amorphous material. Understandably, the analyte may be amorphous particles.

Generally speaking, the composition of each region in the amorphous material is complex and the difference is large, the structure of the amorphous particles is complex, and it is relatively difficult to prepare a sample for nanomechanical testing. However, through the method of this embodiment, it is possible to obtain the Nanomechanical test samples.

In some examples, the analytes are particles of lunar soil. After hundreds of millions of years of meteorite impacts, the bedrock of the moon is melted, crushed, and lithified at high temperatures. The layer forms finely divided lunar soil particles, which contain rock fragments, meteorites, amorphous substances and rich minerals. They are amorphous spherical particles. The study of the mechanical properties of amorphous spherical particles in lunar soil is helpful. Revealing the mechanism of the influence of space weathering on the formation process and properties of amorphous materials has important guiding significance for the preparation and synthesis of high-strength and high-stability amorphous materials. Generally speaking, the content of amorphous substances in lunar soil particles is low, and conventional methods cannot measure and analyze their mechanical properties. However, the method of this embodiment can use the high resolution of the focused ion beam to select and cut lunar soil particles. , to obtain an amorphous sample suitable for nanomechanical testing, and then perform nanoindentation testing on it to obtain information such as modulus and hardness.

In some examples, the analyte can be other particles such as metal particles, ceramic particles, and amorphous glass particles. The method of this embodiment has a wide range of applications, and is also applicable to particles of various shapes, compositions, and structures.

Optionally, the method of using a focused ion beam to extract a sample precursor in the region to be measured of the object to be measured comprises the following steps:

According to the requirements for the sample precursor, determine the area to be detected of the object to be detected, use a focused ion beam to pre-cut the material in the area to be detected and the material in the surrounding area, and use an extraction device to connect the area to be detected Substance, using a focused ion beam to completely cut the substance in the region to be detected and the substance in the surrounding region to obtain the sample precursor.

It can be understood that the focused ion beam processing system described in this embodiment is an electron beam-ion beam dual-beam combined system, and the target particle can be selected as the analyte under the electron beam window according to the size requirements of the sample precursor , and then select the area to be tested on the object to be tested.

Understandably, when the target particle cannot be observed and selected as the analyte from the morphology, the energy spectrometer can be used to select the target particle as the analyte according to the particle composition. Optionally, the energy spectrum acquisition parameters are set as follows: electron beam voltage 20kV-30kV, working distance 3.5mm-4.5mm, effective characteristic X-ray photon count rate>10000cps.

Wherein, according to the resistivity of the object to be measured, the following two methods are used to select the region to be measured on the object to be measured.

When the resistivity of the object to be tested is <450nΩ·m, under the electron beam window of the FIB-SEM dual-beam combined system, and the electron beam voltage is 5kV-30kV, use secondary electrons or backscattering mode to select target particles As the object to be tested, and select the area to be tested on the object to be tested.

When the resistivity of the sample is greater than or equal to 450nΩ·m, it also includes the step of spraying gold on the object to be tested. After the gold spraying treatment, under the electron beam window of the FIB-SEM dual-beam system, the voltage is 5kV-30kV Under certain conditions, the region to be detected of the sample is selected using secondary electron or backscattering mode. Further optionally, the thickness of the gold spray is 5nm-50nm. The purpose of spraying gold is to avoid the drift of the processing window during the preparation of the nanomechanical test sample, which will affect the processing accuracy.

After determining the area to be tested of the object to be tested, the material in the area to be tested and the material in the surrounding area are pre-cut by using the focused ion beam.

Optionally, pre-cutting the substance in the region to be detected and the substance in the surrounding region includes the following steps:

Retaining the connection between a part of the side of the substance in the area to be detected and the substance in the surrounding area, and cutting the remaining side and the substance in the surrounding area;

cutting the bottom of the substance in the region to be detected from the substance in the surrounding region;

Cutting the side of the area to be detected that is connected to the material in the surrounding area and the material in the surrounding area, and retaining the connection between the material in the area to be detected and the material in the surrounding area.

It can be understood that the remaining side of the material in the area to be detected can be vertically cut with the material in the surrounding area. After pre-cutting, a concave-shaped cutting area can be formed when viewed from the top view, which can improve the stability of the sample and avoid subsequent When cutting the bottom, the sample shakes or collapses.

Optionally, when the remaining side of the material in the region to be detected is cut from the material in the surrounding area, the voltage of the ion beam is 20kV-30kV, and the current of the ion beam is 11nA-80nA.

Based on the size requirements of the sample precursor, in some examples, the to-be-cut distance between the bottom edge on one side of the material bottom of the region to be detected and the opposite bottom edge on the other side is greater than 20 μm. At this time, the cutting distance is longer.

When the cutting distance is longer, optionally, cutting and separating the bottom of the material in the area to be detected from the material in the surrounding area includes the following steps:

Taking the bottom edge of one side of the material in the area to be detected as the starting line, after cutting from outside to inside to half the distance to be cut for the first time, taking the opposite bottom edge of the other side as the starting line, the second time Cutting from outside to inside until completely cutting off the connection between the bottom of the material in the area to be detected and the material in the surrounding area.

Further optionally, the cutting planes of the first outside-in cutting and the second outside-in cutting are the same or intersect.

Understandably, when the two cutting surfaces are the same, the bottom after cutting is plane; when the two cutting surfaces intersect, the bottom after cutting is non-planar. In some examples, both the first outside-to-in cut and the second outside-to-in cut are oblique cuts, and after cutting, the bottom is a wedge-shaped section.

Optionally, when cutting from outside to inside for the first time and/or when cutting from outside to inside for the second time, the voltage of the ion beam is 20kV-30kV, and the current of the ion beam is 1.5nA-45nA.

Optionally, when the last side of the material in the region to be detected is cut from the material in the surrounding area, the voltage of the ion beam is 20kV-30kV, and the current of the ion beam is 1.5nA-45nA.

After pre-cutting, a small part of the connection between the material in the area to be tested and the material in the surrounding area remains uncut, and a similar L-shaped gap is formed when viewed from one side.

Use the extraction device to contact the end of the substance in the region to be detected that is far away from the connection with the substance in the surrounding region, weld the extraction device and the substance in the region to be detected by depositing welding materials, and then use the focused ion beam to cut off the region to be detected A small part of the connection between the substance and the substance in the surrounding area makes the substance in the area to be detected completely cut off from the substance in the surrounding area to obtain a sample precursor.

Understandably, the extraction device may be a nano-manipulator.

Optionally, when depositing the welding material, the ion beam voltage is 15kV-30kV, and the ion beam current is 77pA-280pA.

Optionally, the welding material is Pt or C.

The two opposite sides of the sample precursor obtained in this embodiment can be used as the first surface and the second surface respectively. In some examples, the side retained in the above-mentioned pre-cutting is used as the second surface, and the side opposite to it is used as the first surface. surface.

The sample precursor is slowly lifted by the extraction device, and then the second surface of the sample precursor is used as the contact surface, the sample precursor is transferred to the sample carrying device, and the welding material is deposited on the contact surface between the second surface and the sample carrying device, and the The sample precursor is fixed on the sample carrier.

It can be understood that, in order to transfer the sample precursor to the sample holding device with the second surface of the sample precursor as the contact surface, the central axis of the extraction device (nano-manipulator) can be rotated by 180°.

Optionally, the sample carrying device is an M-shaped claw of a special support net for FIB.

Optionally, when depositing the welding material, the ion beam voltage is 15kV-30kV, and the ion beam current is 77pA-280pA.

It can be understood that after the sample precursor is fixed on the sample carrying device, the extraction device is separated from the sample precursor by using an ion beam, and the extraction device is removed.

Optionally, when the ion beam is used to separate the extraction device from the sample precursor, the voltage of the ion beam is 20kV-30kV, and the current of the ion beam is 1.5nA-12nA.

Connect the sample carrying device carrying the sample precursor to the sample stage, adjust the position of the sample carrying device and/or the emission angle of the focused ion beam, so that the focused ion beam bombards the described The first surface is polished to prepare samples for nanomechanical testing.

Different from thinning small-area samples, when the incident angle between the focused ion beam and the first surface is adjusted, the focused ion beam can be used to polish large-area samples, and the thickness of large areas can be reduced under the premise of small thickness changes. The surface roughness of the first surface.

Optionally, the polishing includes first polishing and second polishing;

The first polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam first bombards the first surface at an incident angle of 88°-92°;

The second polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam second bombards the first surface at an incident angle of 86°-94°.

The first polishing is beneficial to remove the damaged layer on the surface of the sample precursor caused by high-current ion beam cutting; the second polishing is beneficial to further improving the surface flatness.

Further optionally, the ion beam voltage of the first bombardment is 20kV-30kV, and the ion beam current is 1.5nA-12nA.

Further optionally, the ion beam voltage of the second bombardment is 20kV-30kV, and the ion beam current is 80pA-1.5nA.

In some examples, based on the limitation of the rotation angle of the sample stage, the position of the sample holder can be adjusted by the following methods:

See Figure 1, take out the sample stage carrying the FIB special support net from the FIB system, adjust the FIB special support net from horizontal to vertical placement, make its plane perpendicular to the plane of the sample stage, and then put the sample stage into the FIB system again , by adjusting the tilt angle of the sample stage, adjust the position of the FIB special support net. It can be understood that when the FIB-specific support net is placed horizontally on the sample stage, due to the limitation of the rotation angle of the sample stage, the FIB-specific support net cannot achieve an ideal tilt angle under the rotation of the sample stage (for example, it is different from the direction in which the ion beam exits). close to parallel), and when the FIB special support net is placed upright on the sample stage, the FIB special support net can achieve an ideal tilt angle (for example, nearly parallel to the direction of the ion beam) under the rotation of the sample stage.

In this embodiment, the focused ion beam is used to select and cut the area to be tested to obtain a sample suitable for nanomechanical testing. The sample with a smooth and clean surface can be obtained through the above method, and the sample and the sample carry The devices are tightly welded, so that the subsequent microcolumn compression test/nano indentation test can be carried out smoothly.

Understandably, after polishing, the samples can be directly used for nanoindentation testing.

When performing a microcolumn compression test on a sample, after polishing, the following steps are also included:

A microcolumn is processed on the first surface by using a focused ion beam for microcolumn compression testing.

Optionally, when the focused ion beam is used to process the microcolumns on the first surface, the voltage of the ion beam is 20kV-30kV, and the current of the ion beam is 80pA-45nA.

The method of this embodiment has high precision and high efficiency, and is a novel preparation method for preparing nanomechanical test samples, which makes it possible to test and analyze the mechanical properties of particles with various shapes and complex components.

Further description will be made below in conjunction with the specific examples. The raw materials involved in the following specific examples, if no special instructions, all can be derived from commercially available, and the instruments used, if no special instructions, all can be derived from commercially available, involved The processes obtained, unless otherwise specified, are routinely selected by those skilled in the art.

The preparation of the nanomechanical test sample of embodiment 1 moon soil sample

In combination with Figures 2 to 9, this embodiment provides a method for preparing samples for nanomechanical testing of lunar soil particles using focused ion beams, the steps are as follows:

1. Selection of particles to be detected

Put the lunar soil particle sample on the sample stage, according to the size requirements of the sample precursor, under the electron beam window of the FIB-SEM dual-beam joint system (sample stage inclination angle 0°), under the condition of the electron beam voltage of 5kV, use The secondary electron mode selects the spherical amorphous particles in the lunar soil particle sample as the analyte, see Figure 2, which is the scanning electron microscope image of the lunar soil particle sample, the spherical particle in the middle is the analyte, determine the In the area to be tested, the lunar soil particle sample comes from Chang'e-5.

2. Pre-cutting of particles to be detected

Tilt the sample stage to the direction facing the ion beam (sample stage inclination angle 54°), under the conditions of ion beam voltage of 30kV and current of 45nA, use the ion beam to first divide the three sides and the surrounding area of the substance to be detected The material in the area is cut vertically, and the connection between the last side and the material in the surrounding area is preserved; then the sample stage is tilted to the direction facing the electron beam (the inclination angle of the sample stage is 0°), at this time, the bottom side of the material in the area to be detected The distance to be cut between the bottom edge and the opposite bottom edge is 28 μm. Under the condition that the ion beam voltage is 30kV and the current is 12nA, taking the bottom edge of the material side of the region to be detected as the starting line, the first time After cutting obliquely downward from the outside to the inside to half the distance to be cut, the lunar soil particle sample is rotated 180° to the bottom edge on the opposite side, with the bottom edge on the other side as the starting line, and the second time is obliquely cut from the outside to the inside. Cut down to completely cut off the connection between the bottom of the material in the area to be detected and the material in the lower area. After cutting, the bottom is a wedge-shaped section; Part of the material in the side and surrounding area is cut, and the connection between the last side of the material in the area to be tested and the material in the surrounding area is reserved, see Figure 3 and Figure 4, Figure 3 is a side view of the material in the area to be tested after pre-cutting It can be seen that the cutting area on the bottom and the last side forms a similar L-shaped notch. Figure 4 is a top view of the material in the area to be tested after pre-cutting. It can be seen that the cutting areas on the three sides form a similar concave-shaped notch. And it can be seen that the distance to be cut between one side of the bottom of the material in the area to be detected and the opposite bottom of the other side is 28 μm. After cutting, the bottom is a wedge-shaped section.

3. Transfer and immobilization of sample precursors

Move the nano-manipulator to the substance in the area to be detected, which is far away from the last side and make contact with it. Under the conditions of the ion beam voltage of 30kV and the current of 80pA, the nano-manipulator and the substance to be detected are welded to each other by depositing Pt. Together, and then under the condition that the ion beam voltage is 30kV and the current is 12nA, cut off a small part of the connection between the last side of the material in the area to be detected and the material in the surrounding area, so that the material in the area to be detected and the material in the surrounding area are completely cut to obtain a sample Precursor, see Figure 5.

Slowly lift the manipulator together with the sample, and rotate the manipulator 180° around its central axis so that the last side is used as the second surface to make it contact the M-shaped claws of the FIB special support net also placed on the sample stage, see Fig. 6. Under the condition of ion beam voltage of 30kV and current of 80pA, deposit Pt at the contact position between the second surface and the M-shaped claw of the support net, fix the sample precursor on the M-shaped claw, and then and the current is 1.5nA, use the ion beam to cut and separate the manipulator and the sample precursor, and then slowly remove the manipulator. At this time, the surface of the sample precursor opposite to the second surface is used as the first surface, and the first surface and the The second surface is parallel, the distance between them is 14.7 μm, and the surface area of the first surface is 900 μm ² .

4. Surface Polishing of Sample Precursors

Take out the sample stage carrying the above-mentioned FIB special support net from the FIB system, adjust the FIB special support net from horizontal to vertical placement, so that its plane is perpendicular to the plane of the sample platform, and then place the above-mentioned FIB special support net again. The sample stage enters the FIB system.

Adjust the inclination angle of the sample stage so that the focused ion beam first bombards the first surface at an incident angle of 88°, the ion beam voltage for the first bombardment is 30kV, and the current is 12nA to complete the first polishing, before removing the sample The damaged layer on the surface of the body is cut by a high-current ion beam, and then the tilt angle of the sample stage is adjusted so that the focused ion beam bombards the first surface for the second time at an incident angle of 86°, and the ion beam voltage for the second bombardment is 30kV , the current is 280pA, to complete the second polishing, to further improve the surface smoothness, to obtain a sample suitable for nanomechanical testing, its side view image is shown in Figure 7, the front view image is shown in Figure 8, and the dashed ellipse The area is the nanomechanical testing area.

The nanoindentation test was carried out in the above test area, and the results are shown in Figure 9. It can be seen from the enlarged part of the indentation that the shape of the indentation is regular, and compared with Figure 8, it can be seen that the sample has not shaken, collapsed, or damaged after the nanoindentation test, indicating that the nanomechanical test sample obtained by the above method can be applied to the nanoindentation test. .

Example 2 Preparation of Nanomechanical Test Samples of Lithium Battery Cathode Particles

Experimental group: The experimental group is basically the same as Example 1, the difference is that the test object is lithium battery cathode particles, and after Step 4, Step 5 is added. For Step 1 to Step 4 of this experimental group, see Step 1 of Example 1 ~ Step 4 and Step 5 are as follows:

5. Microcolumn processing

Tilt the sample stage to the direction facing the ion beam (sample stage inclination angle 54°), under the conditions of ion beam voltage of 30kV and current of 12nA, a circular pit was processed on the polished first surface, and then the ion beam Under the conditions of a voltage of 30kV and a current of 1.5nA, the raised part in the middle of the annular pit was processed into a microcolumn, and a sample suitable for nanomechanical testing was obtained. The front view image of the sample after micro-column processing is shown in Figure 10. It can be seen from the magnification that the shape of the micro-column is regular, the size difference at different heights is small, and the outer surface is smooth without cracks.

The microcolumn compression test was carried out on the sample obtained from the above experimental group. Continue to refer to Figure 10. It can be seen that the typical slip fracture of the microcolumn occurred after compression, and the entire sample did not collapse abnormally, indicating that the nanomechanical test sample obtained by the above method can be applied In microcolumn compression test.

Control group: the control group took the same lithium battery cathode particles as the experimental group, did not perform steps 1 to 4, and directly referred to the step 5 of the experimental group, processed a pit on the surface of the particle to retain a micro-pillar, and obtained a nanomechanical For the tested sample, the front view image of the sample processed by the microcolumn is shown in Fig. 11 .

The microcolumn compression test was carried out on the sample obtained from the above control group. Continue to refer to Figure 11. It can be seen that because the bottom of the particle is an arc-shaped surface, there is no uniform contact with the support material below, resulting in uneven force on the particle when the microcolumn is compressed. It is transmitted to the supporting material below, causing the particles to roll over and collapse, and the micropillars to break abnormally. It can be seen that granular samples cannot be directly processed into microcolumns for nanomechanical testing.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (11)

1. A method utilizing a focused ion beam to prepare a nanomechanical test sample, comprising the following steps: Using a focused ion beam to extract a sample precursor in the region to be measured of the object to be measured, the sample precursor meets the following requirements: 1) having opposite first and second surfaces; and 2) the surface area of the first surface 100μm ² ~ 2500μm ² ; Fixing the second surface on the sample carrying device, adjusting the position of the sample carrying device and/or the emission angle of the focused ion beam, so that the focused ion beam bombards the first surface at an incident angle of 86°-94° , to complete the polishing and prepare samples for nanomechanical testing. 2. the method utilizing focused ion beam to prepare nanomechanical test sample according to claim 1, is characterized in that, described polishing comprises first polishing and second polishing; The first polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam first bombards the first surface at an incident angle of 88°-92°; The second polishing includes the following steps: adjusting the position of the sample carrying device and/or the exit angle of the focused ion beam, so that the focused ion beam second bombards the first surface at an incident angle of 86°-94°. 3. the method utilizing focused ion beam to prepare nanomechanical test sample according to claim 2, is characterized in that, the ion beam voltage of described first bombardment is 20kV～30kV, and ion beam current is 1.5nA～12nA; And/ Or the ion beam voltage for the second bombardment is 20kV-30kV, and the ion beam current is 80pA-1.5nA. 4 . The method for preparing a nanomechanical test sample by using a focused ion beam according to any one of claims 1 to 3 , wherein the distance between the first surface and the second surface is 10 μm to 50 μm. 5. The method for preparing a nanomechanical test sample using a focused ion beam according to any one of claims 1 to 3, characterized in that, the method of extracting a sample precursor in the area to be measured of the object to be measured using a focused ion beam Include the following steps: According to the requirements for the sample precursor, determine the area to be detected of the object to be detected, use a focused ion beam to pre-cut the material in the area to be detected and the material in the surrounding area, and use an extraction device to connect the area to be detected Substance, using a focused ion beam to completely cut the substance in the region to be detected and the substance in the surrounding region to obtain the sample precursor. 6. the method utilizing focused ion beam to prepare nanomechanical test sample according to claim 5, is characterized in that, the material pre-cutting of the material of described region to be detected and surrounding area comprises the following steps: Retaining the connection between a part of the side of the substance in the area to be detected and the substance in the surrounding area, and cutting the remaining side and the substance in the surrounding area; cutting the bottom of the substance in the region to be detected from the substance in the surrounding region; Cutting the side of the area to be detected that is connected to the material in the surrounding area and the material in the surrounding area, and retaining the connection between the material in the area to be detected and the material in the surrounding area. 7. the method utilizing focused ion beam to prepare nanomechanical test sample according to claim 6, is characterized in that, the material bottom one side bottom edge of described area to be detected and the distance to be cut of the other opposite side bottom edge are greater than 20 μm. 8. the method utilizing focused ion beam to prepare nanomechanical test sample according to claim 7, is characterized in that, the material cutting of the material bottom of described region to be detected and surrounding area comprises the following steps: Taking the bottom edge of one side of the material in the area to be detected as the starting line, after cutting from outside to inside to half the distance to be cut for the first time, taking the opposite bottom edge of the other side as the starting line, the second time Cutting from outside to inside until completely cutting off the connection between the bottom of the material in the area to be detected and the material in the surrounding area. 9. the method for utilizing focused ion beam to prepare nanomechanical test sample according to claim 8, is characterized in that, the cutting plane that cuts from outside to inside for the first time and the cutting plane that cuts from outside to inside for the second time is identical or intersects . 10. The method for preparing a nanomechanical test sample using a focused ion beam according to any one of claims 1 to 3, 6 to 9, wherein the analyte satisfies one or more of the following conditions: 1) is granular; and 2) is an amorphous material. 11. The method for preparing a nanomechanical test sample using a focused ion beam according to any one of claims 1 to 3, 6 to 9, characterized in that, after polishing, it also includes the following steps: A microcolumn is processed on the first surface by using a focused ion beam for microcolumn compression testing.