Three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on latitude-longitude type scanning track

Abstract

The application provides a three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on a longitude and latitude scanning track, belongs to the technical field of micro-nano device and cell surface physical property characterization methods, adopts a priori knowledge pre-calibration mode, establishes a longitude scanning path parameter, establishes a latitude scanning path parameter based on a rotating sample table hardware unit and in combination with an eccentricity real-time compensation control algorithm, realizes online compensation of eccentric displacement in the process of rotating along the latitude, takes the normal bending deformation signal of a probe micro-cantilever as feedback through an upper computer, realizes displacement control of a scanning positioning platform, and further realizes synchronous scanning imaging of sample surface topography and nano-mechanical properties. The probe integrated with a front protruding needle tip structure is used as a micro force sensor, a new controllable vector angle single-point servo detection method is combined, the normal bending signal of the probe is used as feedback, the longitude and latitude scanning paths are realized, and synchronous measurement of three-dimensional surface topography and three-dimensional surface mechanical properties of micro-nano spherical samples is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of micro-nano device and cell surface physical property characterization method, and particularly relates to a three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on a latitude-longitude type scanning track. BACKGROUND

[0002] Atomic force microscopy (AFM) is a micro-nano surface property measuring instrument with atomic level high resolution, which is widely used in the research fields of micro-electro-mechanical systems, electronic chips, biological cells, etc. Based on a specific AFM system configuration method, the quantitative characterization of various physical parameters such as micro-nano sample surface topography and mechanical properties can be realized. The grating tracking track is a common scanning path form in the AFM measurement system. At present, the two-dimensional / three-dimensional micro-nano surface property characterization method based on the grating track scanning has been deeply developed and applied. However, for the micro-spherical device structure or suspended spherical cell with sharp surface curvature change, the conventional grating scanning track is difficult to match the tracking servo speed of the positioning platform, and the mapping results of three-dimensional micro-nano spherical surface topography and mechanical properties have problems such as uneven mapping result quality and local distortion.

[0003] The micro-nano surface topography represents the profile change of the micro-nano device or biological sample surface, including surface roughness, geometric key size and other physical information. The surface topography distribution of micro-nano electronic devices is closely related to their threshold voltage, cutoff current, photoelectric conversion efficiency and other functional characteristics. The micro-nano surface mechanical properties include surface adhesion, Young's modulus, stiffness and other mechanical parameters, which are not only the key factors affecting the integration and assembly process of micro-electro-mechanical systems, but also can indirectly reflect the stress state inside the micro-nano device. In addition, the surface topography and mechanical properties of cells have important influence on the life processes such as cell migration, differentiation and growth. Therefore, quantitative evaluation of the coupling relationship between three-dimensional micro-nano device surface topography and three-dimensional surface mechanical properties can provide technical support for optimizing the structure of three-dimensional micro-nano devices and improving the performance of devices, and can provide data basis for in-depth analysis and understanding of the diversification function mechanism of cell basic life unit, which has important significance for semiconductor chip quality improvement and biomedical research.

[0004] In the field of microelectronic research, the surface of three-dimensional micro-nano devices contains diversified topological features, micro-lens array, micro-fluid regulator and some micro-sensors and micro-nano manipulator devices, which respectively use spherical shape to improve focusing power, regulate flow rate, enhance sensitivity and improve positioning accuracy. Three-dimensional micro-nano spherical surface structure is often applied in complex environments such as high temperature, high pressure and corrosive medium, realizes the characterization of physical parameters of three-dimensional micro-nano spherical surface, helps to comprehensively understand the change of micro-nano spherical surface characteristics in different environments, and is very key to the design of micro-nano device structure and material and the optimization of engineering application. In biomedical research, adherent cells and suspended cells are two common forms of cells in vitro culture, and suspended cells are mostly spherical, in addition, some special cells such as oocytes do not exist in the form of adherent cells. Realizing the synchronous characterization of three-dimensional spherical cell surface morphology and mechanical properties is crucial for exploring and controlling the life process of cells. In summary, developing a three-dimensional micro-nano spherical surface multi-parameter mapping method can improve the characterization function of AFM, expand the application of AFM, and at the same time provide necessary detection means for the research of micro-nano spherical surface characteristics.

[0005] Since the traditional AFM three-dimensional surface mapping method mostly adopts raster path to perform scanning imaging, the measured three-dimensional micro-nano structure can be regarded as being composed of single planes with different inclination angles, and there is no continuous and significant curvature change on the surface except the splicing corners between the planes. However, three-dimensional curved surface is also a possible surface morphology in micro-nano devices, but the curvature change of three-dimensional micro-nano spherical surface is large, and limited by the displacement compensation speed of the nano positioning table, the conventional raster scanning path is difficult to adapt to the characterization object of three-dimensional spherical surface with continuous and significant curvature change. SUMMARY

[0006] In view of the shortcomings of the prior art, the present application proposes a three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on a meridian and latitude scanning trajectory, a three-dimensional micro-nano spherical surface multi-parameter synchronous mapping based on an atomic force microscope tracking trajectory feedforward compensation control and a meridian and latitude scanning path, and realizes the synchronous measurement of the three-dimensional surface morphology and three-dimensional surface mechanical properties of the micro-nano spherical sample.

[0007] The present application adopts the following technical solution to solve the above problems:

[0008] The three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on the meridian and latitude scanning trajectory includes but is not limited to two meridian and latitude scanning strategies of meridian fast scanning-latitude slow scanning and meridian slow scanning-latitude fast scanning, and the method includes the following steps:

[0009] S1: using the prior knowledge pre-calibration method, establishing the meridian scanning path parameters including scanning angle step and scanning step number, and combining the eccentric distance real-time compensation control algorithm to establish the latitude scanning path parameters;

[0010] S2: Based on the rotation sample stage hardware unit in the atomic force microscope three-dimensional micro-nano spherical surface characteristic characterization system and the normal bending signal feedback regulation and control of the front protruding needle tip probe, single micro-nano spherical sample three-dimensional surface topography measurement, or micro-nano spherical sample three-dimensional surface topography and mechanical property synchronous measurement;

[0011] S3: In the actual characterization process, on the basis of the pre-calibrated meridian scanning profile, combined with the controllable vector angle servo method, through the interaction force feedback between the needle tip and the sample, the micro displacement error compensation is realized, the eccentric displacement online compensation is realized in the process of rotating along the parallel, combined with the meridian fast scanning-parallel slow scanning or meridian slow scanning-parallel fast scanning meridian and parallel scanning strategy, the micro-nano spherical sample three-dimensional surface topography and mechanical property scanning imaging is realized.

[0012] Further, in S1, a tracking trajectory feedforward compensation control algorithm is adopted, that is, the curvature change trend of the microsphere surface is pre-calibrated, the pre-calibration result is taken as prior knowledge, and is integrated into the scanning detection process of the meridian spherical profile, the motion displacement of the XZ axis is compensated in advance, the eccentricity between the sphere center and the rotation table center is pre-calibrated, the pre-calibration result is integrated into the scanning detection process of the parallel spherical profile, the eccentric error introduced due to the non-coincidence of the sphere center and the rotation table center is compensated in real time, and the needle tip is accurately and continuously measured in situ.

[0013] Further, in S2, the three-dimensional micro-nano spherical surface characteristic characterization system includes a multi-degree-of-freedom AFM system integrated with a micro-nano positioning platform and a rotation sample stage, and an upper computer, the upper computer takes the normal bending deformation signal of the probe micro-cantilever as feedback, realizes the surface topography imaging of a single sample, or the synchronous scanning imaging of the sample surface topography and nanomechanical properties.

[0014] Further, for single three-dimensional micro-nano spherical surface topography measurement, the probe is mechanically driven at the first-order bending resonance frequency of the probe, and for three-dimensional micro-nano spherical surface topography and mechanical property synchronous measurement, the probe is mechanically driven at a low frequency lower than the first-order resonance frequency of the probe.

[0015] Further, in S2, the specific test process of the single micro-nano spherical sample three-dimensional surface topography measurement is as follows:

[0016] S211: Based on the atomic force microscope, a periodically varying voltage input displacement piezoelectric ceramic or electromagnetic coil is used, and a piezoelectric drive or magnetic field drive method is used to mechanically excite the probe at the first-order bending resonance frequency of the probe, so that the probe vibrates at a certain fixed bending amplitude;

[0017] S212: Make the probe approach the sample along the self-defined oblique angle, and obtain the voltage signal curve of the needle tip position when the probe intermittently contacts the sample;

[0018] S213: Continue to approach the probe to the sample along the custom oblique angle until the contact interaction voltage between the probe and the sample reaches the set value, and record the absolute displacement value of the sample at this moment as the sample surface topography.

[0019] Further, in S2, the specific test process of the synchronous measurement of the three-dimensional surface topography and mechanical properties of the micro-nano sphere sample is as follows:

[0020] S221: Based on the atomic force microscope, a periodic voltage input displacement piezoelectric ceramic or electromagnetic coil is used to obtain the voltage signal curve of the free state vibration of the needle tip when the probe approaches the sample by using piezoelectric drive or magnetic field drive at a low frequency of 1-2 kHz to make the probe vibrate at a certain fixed bending amplitude;

[0021] S222: Make the probe approach the sample along the custom oblique angle, and obtain the voltage signal curve of the needle tip position when the probe intermittently contacts the sample, and obtain the voltage signal curve of the force of the probe from the voltage curves of the free vibration state and the intermittent contact vibration state of the probe;

[0022] S223: Continue to approach the probe to the sample along the custom oblique angle until the contact interaction voltage between the probe and the sample reaches the set value, and obtain the force displacement curve by combining the probe stiffness and the sensitivity of the measurement system;

[0023] S224: According to the force displacement curve, the corresponding mechanical model is combined to obtain the corresponding physical properties of the material, including surface topography, adhesion, Young's modulus and other parameters;

[0024] S225: Move to the next test point along the warp or weft direction, and keep the feedback signal of the probe under the mechanical excitation equal to the set value of the interaction voltage between the probe and the sample by adjusting the scanner;

[0025] S226: Repeat step S225 to realize the synchronous imaging measurement of the three-dimensional micro-nano spherical sample surface topography and mechanical properties.

[0026] Further, the test data of each point in the scanning process are obtained by the following methods respectively:

[0027] (1) The three-dimensional surface topography image of the sample is obtained by recording the X coordinate value, Y coordinate value and Z coordinate value of the scanner when the probe reaches the set value of the interaction force;

[0028] (2) In the test process, the adhesion of the sample surface is represented as the maximum negative force generated during the process of the needle tip moving away from the sample surface, which can be obtained by calculating the minimum force value in the interaction force curve between the probe and the sample;

[0029] (3) using a suitable contact mechanics model in AFM, the interaction curve data is fitted, and the three-dimensional surface Young's modulus mapping result of the sample can be obtained;

[0030] (4) fitting the data of the positive indentation area of the interaction force curve to obtain the equivalent stiffness size in the process, and after decoupling the probe stiffness, the imaging result of the three-dimensional surface stiffness distribution of the sample is obtained;

[0031] (5) the mechanical energy loss generated during the whole process of the needle approaching and moving away from the sample is manifested as energy dissipation, the integral area between the approaching and withdrawing curve data in the interaction force curve is fitted, and the three-dimensional surface energy dissipation distribution result of the sample is obtained;

[0032] (6) corresponding to the X-direction coordinate value, Y-direction coordinate value and Z-direction coordinate value recorded at this time, the four-dimensional data corresponding to the surface morphology and surface mechanical properties of the sample can be obtained.

[0033] Further, the contact mechanics model includes but is not limited to Hertz model, Sneddon model, DMT model and JKR model.

[0034] Further, in the latitude-longitude type scanning process, based on the tracking trajectory feedforward compensation control and real-time eccentricity compensation algorithm, combined with the probe deformation with a front protruding needle tip structure and the single-point controllable vector angle servo method, the design concept of synchronous characterization of large curvature three-dimensional micro-nano spherical surface morphology and mechanical properties is realized.

[0035] Further, the multi-degree-of-freedom three-dimensional micro-nano spherical surface characterization system configuration of the integrated rotating sample stage and micro-nano positioning stage in the rotating sample stage hardware unit includes but is not limited to the probe mechanical excitation mode of piezoelectric drive and magnetic drive.

[0036] Advantages of the present application:

[0037] 1. Breakthrough the tracking speed limit of large curvature three-dimensional micro-nano surface morphology and mechanical property synchronous measurement based on grating type scanning trajectory, based on latitude-longitude type scanning trajectory, using the normal bending signal feedback of the probe, combined with controllable vector angle servo, the synchronous characterization of three-dimensional surface morphology and three-dimensional surface mechanical properties of three-dimensional micro-nano spherical structure can be realized;

[0038] 2. The three-dimensional micro-nano spherical surface characterization method based on the latitude-longitude type scanning tracking strategy provides a new idea for further studying three-dimensional micro-nano spherical electronic devices, spherical cell space surface morphology and nanomechanical properties;

[0039] 3. The probe with a front protruding needle tip can detect the physical properties of the space surface below the equator of the three-dimensional micro-nano spherical sample, and the scanning range of the latitude-longitude type tracking trajectory is expanded;

[0040] 4. Configuration of a three-dimensional measurement system integrating piezoelectric and magnetic drives. Compared with traditional AFM, this method can simultaneously characterize the three-dimensional surface morphology and three-dimensional surface nanomechanical properties of micro / nano spherical samples by using the bending signal of the probe as feedback. This is of great significance for the monitoring and control of the overall performance of three-dimensional micro / nano electronic devices and for life science research. It is compatible with the functions of conventional AFM nanomechanical property testing systems and has high practical value in the field of AFM testing methods and systems research. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0043] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0044] Figure 3 This is a schematic diagram of the latitude and longitude scanning detection strategy of the present invention;

[0045] Figure 4 This is a schematic diagram of the latitude and longitude scanning area of ​​the present invention;

[0046] Figure 5 This is a schematic diagram illustrating the eccentricity compensation principle during the latitude scanning process of the present invention.

[0047] Figure 6 This is a schematic diagram of the pre-calibration process of prior knowledge for meridian scanning in this invention;

[0048] Figure 7 This is a schematic diagram of the interaction force curve acquisition process of the present invention;

[0049] Figure 8 This is a global view of the structure of the scanning device used in Example 2;

[0050] Figure 9 yes Figure 8 A schematic diagram of the probe structure of the device;

[0051] Figure 10 yes Figure 8 A schematic diagram of the probe arm of the device;

[0052] Figure 11 yes Figure 8 A schematic diagram of the rotating sample stage of the equipment;

[0053] Figure 12 is a scanning imaging result map of the present application.

[0054] Wherein, 1: rack; 2: four-quadrant position detector two-dimensional adjustment micro platform; 3: first one-dimensional adjustment micro platform; 4: four-quadrant position detector; 5: reflected laser convex lens; 6: laser reflector; 7: probe hand; 7-1: probe hand base; 7-2: displacement piezoelectric ceramic; 7-3: probe base; 7-4: probe with front protruding needle tip; 7-4-1: clippable silicon base; 7-4-2: magnetic ball; 7-4-3: micro cantilever; 7-4-4: front protruding needle tip; 7-5: probe fixing plate; 7-6: high-frequency excitation piezoelectric ceramic sheet; 7-7: terminal; 8: first XYZ micrometer positioning table; 9: first XYZ nanometer positioning table; 10: probe hand support; 11: one-dimensional large-range adjustment micro platform; 12: table top; 13: second XYZ micrometer positioning table; 14: second XYZ nanometer positioning table; 15: sample table support; 16: rotary sample table; 16-1: rotary sample table base; 16-2: electromagnetic coil support; 16-3: rotary positioning table; 16-4: sample base; 16-5: sample; 16-6: set screw; 16-7: electromagnetic coil; 16-8: ferrite core; 16-9: electromagnetic coil connecting wire; 17: incident laser focusing convex lens; 18: second one-dimensional adjustment micro platform; 19: semiconductor laser generator; 20: laser generator angle adjustment mechanism; 21: optical microscope. DETAILED DESCRIPTION

[0055] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be described in detail below in combination with the drawings and specific embodiments.

[0056] The present application adopts a priori knowledge pre-calibration method to establish meridian scanning path parameters including scanning angle step and scanning step number; based on a rotary sample table hardware unit, combined with an eccentricity real-time compensation control algorithm, to establish parallel scanning path parameters, to realize online compensation of eccentric displacement during rotation along the parallel; a three-dimensional micro-nano spherical surface characteristic characterization system mainly comprises a multi-freedom degree AFM system integrated with a micro-nano positioning platform and a rotary sample table, and an upper computer; for single three-dimensional micro-nano spherical surface topography measurement, the probe is mechanically driven at the first-order bending resonance frequency of the probe; for three-dimensional micro-nano spherical surface topography and mechanical property synchronous measurement, the probe is mechanically driven at a low frequency lower than the first-order resonance frequency of the probe; the upper computer takes the normal bending deformation signal of the probe micro-cantilever as feedback to realize displacement control of the scanning positioning platform, and then realize synchronous scanning imaging of the sample surface topography and nano-mechanical properties.

[0057] Embodiment 1

[0058] As Figures 1-7As shown, the present application proposes a three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on a latitude-longitude scanning track, including but not limited to two kinds of latitude-longitude scanning strategies of longitude fast scanning-latitude slow scanning and longitude slow scanning-latitude fast scanning, Figure 3 In the figure, (A) is a longitude scanning detection strategy of fast-axis longitude & slow-axis latitude scanning, (B) is a latitude scanning detection strategy of fast-axis latitude & slow-axis longitude; the system structure diagram of the present application is as shown in Figure 1 、 Figure 2 As shown in the figure, Figure 1 In the figure, ① is a piezoelectric ceramic drive, and ② is a magnetic field drive. Figure 2 In the figure, B is the direction of the electromagnetic field, m is the magnetization direction of the magnetic sphere, and τ is the torque direction of the magnetic sphere, and specifically includes the following steps:

[0059] S1: A priori knowledge pre-calibration is adopted to establish longitude scanning path parameters including scanning angle step and scanning step number, and to establish latitude scanning path parameters in combination with eccentricity real-time compensation control algorithm.

[0060] A tracking trajectory feedforward compensation control algorithm is adopted, that is, the change trend of the microsphere surface curvature is pre-calibrated, the pre-calibration result is taken as prior knowledge, is integrated into the scanning detection process of the longitude spherical surface profile, and the motion displacement of the XZ axis is compensated in advance, the eccentricity between the sphere center and the center of the rotating table is pre-calibrated, the pre-calibration result is integrated into the latitude spherical surface profile scanning detection process, the eccentric error introduced due to the fact that the sphere center and the center of the rotating table do not completely coincide is compensated in real time, and accurate continuous in-situ measurement of the needle tip is ensured; if the scanning measurement process is not compensated in real time, the measured spherical surface is offset relative to the needle tip after rotation, after compensation, the point which has been offset can be moved back to the original position, so that the actual measured point and the next point which should be measured in theory can be ensured to be consistent, and the accuracy is improved.

[0061] S2: Based on the normal bending signal feedback regulation of the rotating sample table hardware unit and the normal bending signal feedback regulation of the atomic force microscope three-dimensional micro-nano spherical surface characteristic system with a front protruding needle tip probe, three-dimensional surface topography measurement of a single micro-nano sphere sample, or three-dimensional surface topography and mechanical characteristic synchronous measurement of a micro-nano sphere sample;

[0062] The three-dimensional micro-nano spherical surface characteristic system includes a multi-degree-of-freedom AFM system integrated with a micro-nano positioning platform and a rotating sample table, and an upper computer; the upper computer takes the normal bending deformation signal of the probe micro-cantilever as feedback, realizes surface topography imaging of a single sample, or synchronous scanning imaging of sample surface topography and nano mechanical characteristics, when facing single three-dimensional micro-nano spherical surface topography measurement, mechanically drives the probe at the first-order bending resonance frequency of the probe, and when facing three-dimensional micro-nano spherical surface topography and mechanical characteristic synchronous measurement, mechanically drives the probe at a low frequency lower than the first-order resonance frequency of the probe.

[0063] The specific test process of the single micro-nanosphere sample three-dimensional surface topography measurement is as follows:

[0064] S211: Based on the atomic force microscope, a periodically changing voltage input displacement piezoelectric ceramic or electromagnetic coil is used to mechanically excite the probe at the first-order bending resonance frequency of the probe, so that the probe vibrates at a certain fixed bending amplitude.

[0065] S212: The probe is made to approach the sample along a self-defined oblique angle, and the voltage signal curve of the probe needle tip position when the probe intermittently contacts the sample is obtained.

[0066] S213: The probe is continuously made to approach the sample along the self-defined oblique angle until the contact action voltage between the probe and the sample reaches the set value, and the absolute displacement value of the sample at this moment is recorded as the surface topography of the sample.

[0067] The specific test process of the micro-nanosphere sample three-dimensional surface topography and mechanical property synchronous measurement is as follows:

[0068] S221: Based on the atomic force microscope, a periodically changing voltage input displacement piezoelectric ceramic or electromagnetic coil is used to mechanically excite the probe at a low frequency of 1-2 kHz, so that the probe vibrates at a certain fixed bending amplitude, and the voltage signal curve of the probe needle tip free state vibration when the probe approaches the sample is obtained.

[0069] S222: The probe is made to approach the sample along a self-defined oblique angle, and the voltage signal curve of the probe needle tip position when the probe intermittently contacts the sample is obtained, and the voltage signal curve of the probe force is obtained from the voltage curves of the probe free vibration state and the intermittent contact vibration state.

[0070] S223: The probe is continuously made to approach the sample along the self-defined oblique angle until the contact action voltage between the probe and the sample reaches the set value, and the force displacement curve is obtained in combination with the probe stiffness and the measurement system sensitivity.

[0071] S224: According to the force displacement curve, the corresponding mechanical model is combined to obtain the corresponding physical properties of the material, including surface topography, adhesion, Young's modulus and other parameters.

[0072] S225: Along the warp or weft direction, move to the next test point of the sample, and keep the feedback signal of the probe under the mechanical excitation equal to the set value of the interaction voltage between the probe and the sample by adjusting the scanner.

[0073] S226: Repeat step S225 to realize the synchronous imaging measurement of the three-dimensional micro-nanosphere sample surface topography and mechanical properties.

[0074] S3: In the actual characterization process, on the basis of the pre-calibrated meridian scanning profile, combined with the controllable vector angle servo method, through the interaction force feedback between the needle tip and the sample, the micro displacement error compensation is realized, the on-line compensation of eccentric displacement is realized in the rotation along the latitude, combined with the meridian fast scan-latitude slow scan or meridian slow scan-latitude fast scan meridian-latitude scanning strategy, the three-dimensional surface morphology and mechanical property scanning imaging of micro-nano sphere sample is realized.

[0075] It should be noted that the test data of each point in the scanning process is obtained by the following method:

[0076] (1) The three-dimensional surface morphology image of the sample is obtained by recording the X coordinate value, Y coordinate value and Z coordinate value of the scanner when the probe reaches the interaction force set value;

[0077] (2) In the test process, the adhesion force of the sample surface is the maximum negative force generated in the process of the needle tip moving away from the sample surface, which can be obtained by calculating the minimum force value in the interaction force curve between the probe and the sample;

[0078] (3) A suitable contact mechanics model in AFM is used, including but not limited to Hertz model, Sneddon model, DMT model and JKR model.

[0079] The interaction curve data is fitted, and the three-dimensional surface Young's modulus mapping result of the sample is obtained;

[0080] (4) The data of the positive indentation area of the interaction force curve is fitted to obtain the equivalent stiffness size in this process, and after decoupling the probe stiffness, the imaging result of the three-dimensional surface stiffness distribution of the sample is obtained;

[0081] (5) The mechanical energy loss in the whole process of the needle tip approaching and moving away from the sample is shown as energy dissipation, the integral area between the approaching and withdrawing curve data in the interaction force curve is fitted to obtain the three-dimensional surface energy dissipation distribution result of the sample;

[0082] (6) Corresponding to the recorded X coordinate value, Y coordinate value and Z coordinate value, the four-dimensional data corresponding to the sample surface morphology and surface mechanical properties can be obtained.

[0083] It should be noted that in the meridian-latitude scanning process, based on the tracking trajectory feedforward compensation control and real-time eccentricity compensation algorithm, combined with the probe deformation with forward protruding needle tip structure and single-point controllable vector angle servo method, the design concept of synchronous characterization of large curvature three-dimensional micro-nano sphere surface morphology and mechanical properties is realized.

[0084] It is to be noted that the configuration of the integrated rotating sample stage and multi-freedom three-dimensional micro-nano spherical surface characterization system of the micro-nano positioning stage in the rotating sample stage hardware unit includes, but is not limited to, the probe mechanical excitation mode of piezoelectric drive and magnetic drive.

[0085] Embodiment 2

[0086] As a preferred embodiment of the present application, as shown in Figure 8 -- Figure 10 The atomic force microscope three-dimensional micro-nano spherical surface characterization system includes a table 12, a rack 1, a one-dimensional large-range adjustment micro platform 11, a second XYZ micro positioning stage 13 and an optical microscope 21 installed on the table 12. Among them, the rotating sample stage 16 is installed on the second XYZ micro positioning stage 13 through the sample stage support 15 and the second XYZ nano positioning stage 14, the laser force measurement system is installed on the rack 1, and the probe hand 7 is installed on the one-dimensional large-range adjustment micro platform 11 through the probe hand support 10, the first XYZ nano positioning stage 9 and the first XYZ micro positioning stage 8. The first XYZ nano positioning stage 9 and the second XYZ nano positioning stage 14 are independent, and the controllable vector angle servo between the probe and the sample is completed through the decoupled motion cooperation.

[0087] The laser force measurement system is composed of a laser generator angle adjustment mechanism 20, a semiconductor laser generator 19, an incident laser focusing convex lens 17, a laser reflecting mirror 6, a reflecting laser convex lens 5 and a four-quadrant position detector 4, as well as a second one-dimensional adjustment micro platform 18, a first one-dimensional adjustment micro platform 3 and a four-quadrant position detector two-dimensional adjustment micro platform 2.

[0088] The probe hand 7 is composed of a probe hand base 7-1, a displacement piezoelectric ceramic 7-2, a probe base 7-3, a probe with a front needle tip 7-4, a probe fixing plate 7-5, a high-frequency excitation piezoelectric ceramic sheet 7-6 and a terminal 7-7. Among them, there are insulating sheets between the probe hand base 7-1 and the displacement piezoelectric ceramic 7-2, the displacement piezoelectric ceramic 7-2 and the probe base 7-3, the probe base 7-3 and the high-frequency excitation piezoelectric ceramic sheet 7-6, and the high-frequency excitation piezoelectric ceramic sheet 7-6 and the probe fixing plate 7-5. The displacement piezoelectric ceramic 7-2 and the high-frequency excitation piezoelectric ceramic sheet 7-6 are electrically connected to the corresponding terminal 7-7 interface. The terminal 7-7 is electrically connected to the corresponding electrical equipment. The stress deformation of the probe is measured by the laser force measurement system.

[0089] The schematic diagram of the rotating sample stage of the present application is as shown in Figure 11As shown in the figures, (A) and (B) are respectively an axial view and a top view and a sectional view of the rotating stage, and the rotating sample stage 16 is composed of a rotating sample stage base 16-1, an electromagnetic coil support 16-2, a rotating positioning stage 16-3, a sample seat 16-4, a sample 16-5, a set screw 16-6, an electromagnetic coil 16-7, a ferrite core 16-8, and an electromagnetic coil connecting wire 16-9, wherein the sample 16-5 is fixed with the sample seat 16-4, and both are installed on the rotating positioning stage 16-3 through the set screw 16-6, the rotating positioning stage 16-3, the electromagnetic coil support 16-2, and the rotating sample stage base 16-1 are connected as a whole through the set screw 16-6, the ferrite core 16-8 and the electromagnetic coil 16-7 are fixed in the hollow cavity of the rotating positioning stage 16-3 by the electromagnetic coil support 16-2, and the electromagnetic coil connecting wire 16-9 is electrically connected with the corresponding electrical equipment, which can generate a uniform magnetic field to realize the magnetic driving of the probe, and there are insulating sheets between the ferrite core 16-8, the electromagnetic coil 16-7, the electromagnetic coil support 16-2, and the rotating positioning stage 16-3.

[0090] The probe 7-4 with a front protruding needle tip is composed of a claspable silicon base 7-4-1, a magnetic ball 7-4-2, a micro cantilever 7-4-3, and a front protruding needle tip 7-4-4. The magnetic ball 7-4-3 functions to drive the probe through the magnetic field generated by the electromagnetic coil 16-7. In the test, the front protruding needle tip 7-4-4 of the probe interacts with the surface of the three-dimensional micro-nano spherical sample, thereby causing the probe to be forced to produce normal deflection deformation, and the signal is detected by the laser force measuring system and used for feedback control of the entire scanning process. Based on the controllable vector angle servo method, the distance error between the sample and the tip can be compensated by the relative motion of the first XYZ nano positioning stage 9 along the self-defined oblique angle, and then combined with the latitude-longitude type scanning to realize three-dimensional imaging.

[0091] The specific content of the latitude-longitude type scanning strategy is as follows: in the latitude scanning process, the rotation step angle is set as Δθ, the step number is m, and the total angle size of the latitude scanning direction is θ (θ = m × Δθ); the latitude direction scanning process is completed by using the rotating sample stage (16), during which, due to the eccentricity between the to-be-tested spherical sample and the rotation center, the XY axis motion displacement of the second XYZ nano positioning stage (14) is needed to drive, and real-time eccentricity compensation is needed, if the eccentricity size is R e , then the compensation displacement size of the second XYZ nano positioning stage (14) is:

[0092] ΔX = R e (1-cos(Δθ))

[0093] ΔY = R e sin(Δθ)

[0094] where Δθ is the rotation step angle, R e is the distance between the sphere center and the rotation center, i.e. the eccentricity, and ΔX and ΔY are the displacements of the X and Y axes of the second XYZ nano-positioning stage (14) to be compensated, respectively.

[0095] In the meridian scanning process, the meridian step angle is set as Δβ, the step number is n, and the total angle size of the meridian scanning direction is β (β = n x Δβ); the meridian angle displacement is decomposed into the movement displacement (ΔX and ΔZ) of the XZ axes of the second XYZ nano-positioning stage (14) by using the second XYZ nano-positioning stage (14) to control the meridian scanning process; when the step angle is Δβ, the movement displacement of the XZ axes of the second XYZ nano-positioning stage (14) is:

[0096] ΔX = R sp (cos(β0+Δβ)-cos(β0))

[0097] ΔZ = R sp (sin(β0+Δβ)-sin(β0))

[0098] where R sp is the radius of the microsphere obtained by preliminary calibration, β0 is the angle between the needle tip-sphere center and the horizontal line after the end of the previous scanning, i.e. the initial angle before the start of the current step scanning, Δβ is the meridian step angle, and ΔX and ΔZ are the step displacements of the X and Z axes of the XYZ nano-positioning stage II (14), respectively.

[0099] The above meridian scanning process applies a tracking trajectory feedforward compensation control algorithm, i.e. the variation trend of the microsphere surface curvature is pre-calibrated, the pre-calibration result is taken as prior knowledge, is integrated into the scanning detection process of the meridian spherical surface, and the movement displacement of the XZ axes of the second XYZ nano-positioning stage (14) is compensated in advance; in the actual characterization process, on the basis of the compensated spherical surface profile, the controllable vector angle servo method is combined, and the micro displacement error compensation is realized through the interaction force feedback between the needle tip and the sample; thus, the problems of slow tracking speed of the nano-positioning stage and distorted scanning result are solved, and the scanning speed and measurement accuracy are improved; the pre-calibration content includes the radius of the microsphere sample to be detected, the sphere center coordinates, and the initial scanning point coordinates, the initial angle β0 is determined from the sphere center coordinates and the initial scanning point coordinates, the initial angle before each step is iteratively generated according to the meridian step angle Δβ, and then ΔX and ΔZ are obtained, and the meridian scanning detection is completed; finally, the scanning area size can be expressed as a circular sector area covered by θ x β angles.

[0100] The application breaks through the limitation of traditional grating scanning track which can only be applied to two-dimensional micro-nano sample and regular three-dimensional micro-nano sample surface characteristic characterization without continuous and significant curvature change, and can realize three-dimensional surface morphology and mechanical characteristic measurement of micro-nano sphere sample by using normal bending signal feedback regulation of the probe with a front protruding needle tip. The specific embodiments of the application are described in more details as follows.

[0101] 1. System initialization, calibrating the center point coordinate of the rotating sample table 16, fixing the prepared micro-nano sphere sample 16-5 to the sample seat 16-4, accurately placing the micro-nano sphere sample 16-5 at the center point of the rotating sample table 16 by using high-precision micro-operation technology, installing the probe 7-4 with a front protruding needle tip on the probe hand 7, then respectively installing the rotating sample table 16 and the probe hand 7 on the sample table support 15 and the first XYZ nanometer positioning table 9, and finally electrically connecting the terminal with the corresponding equipment.

[0102] 2. Moving the second XYZ micrometer positioning table 13, preliminarily positioning the sample 16-5 by the optical microscope 21, selecting a suitable measurement area, and moving the area to the center of the field of view of the optical microscope 21.

[0103] 3. Calibrating the distance between the sphere sample 16-5 and the center of the rotating sample table 16, i.e. the eccentricity R e , moving the one-dimensional large-range adjustment micro-platform 11 and the first XYZ micrometer positioning table 8, roughly aligning the probe 7-4 with a front protruding needle tip, placing the probe needle tip above the suitable measurement area selected in the second step, and adjusting the laser spot of the probe 7-4 to the center of the front end of the probe micro-cantilever.

[0104] 4. Pre-calibrating the surface profile of the micro-nano sphere sample 16-5, including the sphere diameter, sphere center and initial scanning point coordinate. Setting the voltage reference value when the probe contacts the sample, driving the second XYZ nanometer positioning table 14 to rise along the Z axis until the probe deformation voltage signal reaches the set value, and recording the X direction coordinate value, Y direction coordinate value and Z direction coordinate value at this time.

[0105] 5. Making the second XYZ nanometer positioning table 14 descend along the Z axis and drive it to laterally displace along the X axis, repeating the step 4 operation again, and continuously repeating 6 times, fitting the sphere center coordinate and sphere radius according to the position coordinates of the 6 recorded sphere points.

[0106] 6. Determining the scanning position, driving the second XYZ nanometer positioning table 14 along a certain angle α so that the probe contacts the sample and reaches the contact voltage reference value, recording the X direction coordinate value, Y direction coordinate value and Z direction coordinate value at this time, then returning the second XYZ nanometer positioning table 14 to the initial position at the beginning of the step 6, and determining the initial scanning angle β0 by using the recorded coordinate values and the fitted sphere center coordinate.

[0107] 7. Drive the first XYZ nano-positioning stage 9 along the same relative vector angle a as step 6, so that the probe 7-4 feeds along the same angle as step 6 to the sample 16-5 until the probe 7-4 contacts the sample 16-5 and reaches the set value of the interaction force between the probe and the sample.

[0108] 8. Re-adjust the laser spot of the probe 7-4 with the front protruding needle tip to the center of the front end of the probe micro-cantilever, and prepare to start the host computer-position servo control.

[0109] 9. Mechanically excite the probe at the first-order bending resonance frequency (U m ), The present application introduces two driving modes, but is not limited to these two driving modes: 1) piezoelectric ceramic driving, the mechanical vibration of the probe at its first-order bending resonance frequency is realized through the displacement of the piezoelectric ceramic 7-2 driven by a sinusoidal voltage; 2) magnetic field driving, the magnetic sphere 7-4-2 magnetized in a specified direction is driven by an alternating magnetic field generated by the electromagnetic coil 16-7 in the rotating sample stage 16 under the driving of a sinusoidal voltage signal, so that the mechanical vibration of the probe at its first-order bending resonance frequency is realized through the electromagnetic torque τ. The deformation signal (voltage signal) generated by the probe 7-4 is detected by the laser force measurement system, the difference between the probe deformation voltage and the set voltage is calculated, and then the position servo control is started to control the X-axis coordinate and the Z-axis coordinate of the first XYZ nano-positioning stage 9, so that the probe 7-4 quickly approaches the sample 16-5 at a self-defined vector angle in the XZ plane until the processed probe deformation voltage is equal to the set value, and the absolute displacement value of the sample at this moment is recorded as the sample surface topography.

[0110] 10. Input the calibrated eccentricity, micro-nano sphere sample radius, initial scanning angle and other parameters into the host computer, activate the real-time eccentricity compensation and feedforward compensation control program, set the scanning step distance and scanning point number corresponding to the latitude-longitude type scanning track, and then start the three-dimensional spherical surface topography scanning imaging.

[0111] Example 3

[0112] This embodiment is aimed at synchronous measurement of three-dimensional micro-nano spherical surface topography and mechanical properties, and the probe is mechanically driven at a low frequency lower than the first-order resonance frequency, and the remaining technical features are the same as those of example 2.

[0113] The difference between this embodiment and example 2 is that the mechanical excitation frequencies of single topography imaging and topography and mechanics synchronous imaging are different, and the signal processing is a little simpler.

[0114] The measurement steps 1-8 of this embodiment are the same as those of example 2, and after preparing to start the host computer-position servo control, the following steps are included:

[0115] 9'. Mechanically excite the probe at a frequency of 1-2 kHz (U m), the application introduces two driving modes, but is not limited to the two driving modes: 1) piezoelectric ceramic driving, the mechanical vibration of the probe at the low-order frequency is realized through the displacement piezoelectric ceramic 7-2 under the driving of the sinusoidal voltage; 2) magnetic field driving, the magnetic ball 7-4-2 after specified direction magnetization is driven by the alternating magnetic field generated by the electromagnetic coil 16-7 in the rotating sample table 16 under the driving of the sinusoidal voltage signal, so that the mechanical vibration of the probe at the low-order frequency is realized through the electromagnetic torque τ; the deformation signal generated by the probe 7-4 is detected by using the laser force measurement system, the driving signal generated by the signal generator is taken as a reference signal, the difference signal between the real-time deformation signal of the probe and the reference voltage signal is obtained through the upper computer, and the peak voltage of the difference signal in a single cycle is analyzed, the difference between the peak voltage and the interaction setting value is calculated, then the position servo control is started, the X-axis coordinate and the Z-axis coordinate of the first XYZ nanometer positioning table 9 are controlled, so that the probe 7-4 quickly approaches the sample 16-5 at a self-defined vector angle in the XZ plane, until the peak voltage obtained by processing is equal to the interaction setting value.

[0116] 10', the probe stiffness and the system measurement sensitivity are input into the upper computer, the interaction voltage signal obtained by processing, that is, the difference signal between the real-time deformation signal of the probe and the reference voltage signal is converted into a force displacement curve. Combined with the corresponding contact mechanics model, the adhesion force, Young's modulus and other nanomechanical characteristic parameters are analyzed and obtained.

[0117] 11', the calibrated eccentricity, the micro-nano sphere sample radius, the initial scanning angle and other parameters are input into the upper computer, the real-time eccentricity compensation and feedforward compensation control program is activated, the scanning step and the scanning point number corresponding to the latitude-longitude type scanning track are set, and then the three-dimensional spherical surface topography and mechanical characteristic synchronous scanning imaging is started.

[0118] The device and method in the application measure and scan the three-dimensional microsphere structure; the three-dimensional scanning image result of the microsphere sample is as follows Figure 12(A) is a three-dimensional micro-nano sphere surface topography map obtained under a single three-dimensional micro-nano sphere surface topography measurement condition, in which a color bar represents a height difference between a Z-direction coordinate and a fitted circle; (B) is a three-dimensional micro-nano sphere surface topography profile curve map corresponding to (A), which shows a fitted circle trajectory and a fitted circle center position; (C) is a three-dimensional micro-nano sphere surface topography map obtained under a three-dimensional micro-nano sphere surface topography and mechanical property synchronous measurement condition, in which a color bar represents a height difference between a Z-direction coordinate and a fitted circle; (D) is a three-dimensional micro-nano sphere surface topography profile curve map corresponding to (C), which shows a fitted circle trajectory and a fitted circle center position; (E) is a three-dimensional micro-nano sphere surface adhesion force map, in which a color bar represents a surface adhesion force value; (F) is a three-dimensional micro-nano sphere surface Young's modulus map, in which a color bar represents a surface Young's modulus value; (G) is a three-dimensional micro-nano sphere surface stiffness map, in which a color bar represents a surface stiffness value; (H) is a three-dimensional micro-nano sphere surface energy dissipation map, in which a color bar represents a surface energy dissipation value.

[0119] The above detailed description of the present application is made through the embodiments, but the content is only the preferred embodiments of the present application, and cannot be considered as limiting the implementation scope of the present application. Any equivalent changes and improvements made according to the scope of the present application should still belong to the patent coverage scope of the present application.

Claims

1. A three-dimensional micro-nano spherical surface multi-parameter synchronous mapping method based on a latitude-longitude type scanning track, characterized in that: The method comprises two kinds of warp-weft scanning strategies, warp fast scanning-weft slow scanning and warp slow scanning-weft fast scanning, and comprises the following steps: S1: using prior knowledge pre-calibration method, the warp scanning path parameters including scanning angle step and scanning step number are established, and the real-time compensation control algorithm of eccentric distance is combined to establish the weft scanning path parameters; S2: based on the three-dimensional micro-nano spherical surface characteristic characterization system of atomic force microscope, the hardware unit of rotating sample table and the normal bending signal feedback regulation of the probe with front protruding needle tip are combined, the three-dimensional surface topography measurement of single micro-nano sphere sample or the three-dimensional surface topography and mechanical property synchronous measurement of micro-nano sphere sample are realized; S3: in the actual characterization process, based on the pre-calibrated warp scanning profile, combined with the controllable vector angle servo method, the micro displacement error compensation is realized through the interaction force feedback between the needle tip and the sample, combined with the warp fast scanning-weft slow scanning or warp slow scanning-weft fast scanning warp-weft scanning strategy, the three-dimensional surface topography and mechanical property scanning imaging of micro-nano sphere sample is realized.

2. The method according to claim 1, wherein the method is characterized in that: In S1, a tracking trajectory feedforward compensation control algorithm is adopted, that is, the change trend of microsphere surface curvature is pre-calibrated, the pre-calibration result is taken as prior knowledge, and is integrated into the scanning detection process of the meridional spherical profile to compensate the motion displacement of XZ axis in advance, the eccentricity between the sphere center and the center of the rotating table is pre-calibrated, the pre-calibration result is integrated into the scanning detection process of the latitudinal spherical profile to compensate the eccentric error introduced by the non-coincidence of the sphere center and the center of the rotating table in real time, and the needle tip is accurately and continuously measured in situ.

3. The method of claim 1, wherein the method is based on a latitude-longitude scanning trajectory. In S2, the three-dimensional micro-nano spherical surface characteristic characterization system includes a multi-degree-of-freedom AFM system integrated with a micro-nano positioning platform and a rotating sample table, and a host computer, which takes the normal bending deformation signal of the probe micro-cantilever as feedback to realize the imaging of single sample surface topography, or the synchronous scanning imaging of sample surface topography and nanomechanical properties.

4. The method of claim 3, wherein the method is based on a latitude-longitude scanning trajectory. For single three-dimensional micro-nano spherical surface topography measurement, the probe is mechanically driven at the first-order bending resonance frequency of the probe, and for three-dimensional micro-nano spherical surface topography and mechanical property synchronous measurement, the probe is mechanically driven at a low frequency lower than the first-order resonance frequency of the probe.

5. The method of claim 1, wherein the method is based on a latitude-longitude scanning trajectory. In S2, the specific test process of the three-dimensional surface topography measurement of single micro-nano sphere sample is as follows: S211: based on atomic force microscope, periodic voltage input displacement piezoelectric ceramic or electromagnetic coil is used, piezoelectric drive or magnetic field drive method is used to mechanically excite the probe at the first-order bending resonance frequency of the probe, so that the probe vibrates at a certain fixed bending amplitude; S212: make the probe approach the sample along the self-defined oblique angle, and obtain the voltage signal curve of the needle tip position when the probe intermittently contacts the sample; S213: continuously approach the sample along the self-defined oblique angle, until the contact action voltage between the probe and the sample reaches the set value, and record the absolute displacement value of the sample at this moment as the sample surface topography.

6. The method of claim 1, wherein the method is based on a latitude-longitude scanning trajectory. In S2, the specific test process of the three-dimensional surface topography and mechanical property synchronous measurement of micro-nano sphere sample is as follows: S221: Based on atomic force microscope, a periodic voltage input displacement piezoelectric ceramic or electromagnetic coil is used to drive the probe in a low frequency of 1-2 kHz, so that the probe vibrates at a fixed bending amplitude, and a voltage signal curve of the free state vibration of the probe needle tip is obtained when the probe approaches the sample; S222: The probe is made to approach the sample at a self-defined oblique angle, and a voltage signal curve of the position of the probe needle tip when the probe intermittently contacts the sample is obtained, and a voltage signal curve of the force on the probe is obtained from the voltage curves of the free vibration state and the intermittent contact vibration state of the probe; S223: The probe is continuously made to approach the sample at a self-defined oblique angle until the contact interaction voltage between the probe and the sample reaches a set value, and the force-displacement curve is obtained in combination with the probe stiffness and the sensitivity of the measurement system; S224: According to the force-displacement curve, the corresponding physical properties of the material are obtained in combination with the corresponding mechanical model, including the surface topography, the adhesion, and the Young's modulus parameters; S225: The sample is moved to the next test point along the warp or weft direction, and the feedback signal of the probe under the mechanical excitation is kept equal to the set value of the interaction voltage between the probe and the sample by adjusting the scanner; S226: Step S225 is repeated to realize the synchronous imaging measurement of the surface topography and the mechanical properties of the three-dimensional micro-nano spherical sample.

7. The method of claim 1, wherein the method is based on a latitude-longitude scanning trajectory. The test data of each point during the scanning process are obtained in the following ways: (1) The three-dimensional surface topography image of the sample is obtained by recording the X, Y and Z coordinate values of the scanner when the probe reaches the set value of the interaction force; (2) During the test process, the adhesion of the sample surface is represented by the maximum negative force generated during the process of the needle tip moving away from the sample surface, which can be obtained by calculating the minimum force value in the interaction force curve between the probe and the sample; (3) The three-dimensional surface Young's modulus mapping result of the sample is obtained by fitting the interaction curve data using a suitable contact mechanics model in the AFM; (4) The equivalent stiffness size in this process is obtained by fitting the data in the positive indentation area of the interaction force curve, and the imaging result of the three-dimensional surface stiffness distribution of the sample is obtained after decoupling the probe stiffness; (5) The mechanical energy loss during the whole process of the needle tip approaching and moving away from the sample is represented as energy dissipation, and the integral area between the approaching and withdrawing curve data in the interaction force curve is fitted to obtain the three-dimensional surface energy dissipation distribution result of the sample; (6) The four-dimensional data corresponding to the surface topography and the surface mechanical properties of the sample are obtained according to the recorded X, Y and Z coordinate values.

8. The method of claim 7, wherein the method is based on a latitude-longitude scanning trajectory. The contact mechanics model includes Hertz model, Sneddon model, DMT model and JKR model.

9. The method according to any one of claims 1-8, wherein the method is a method for three-dimensional micro-nano spherical surface multi-parameter synchronous mapping based on a latitude-longitude scanning trajectory. In the warp-weft scanning process, based on the tracking trajectory feedforward compensation control and real-time eccentricity compensation algorithm, in combination with the probe deformation with a front needle tip structure and the single-point controllable vector angle servo method, the design concept of synchronous characterization of the surface topography and the mechanical properties of the large-curvature three-dimensional micro-nano sphere is realized.

10. The method of claim 1-8, wherein the method is based on a latitude-longitude scanning trajectory for three-dimensional micro-nano spherical surface multi-parameter synchronous mapping. The multi-freedom three-dimensional micro-nano spherical surface characterization system configuration of the integrated rotary sample stage and micro-nano positioning stage in the rotary sample stage hardware unit includes a piezoelectric drive and a magnetic drive probe mechanical excitation mode.

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