CN105241908A - Improved scanning method for scanning probe microscope - Google Patents
Improved scanning method for scanning probe microscope Download PDFInfo
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- CN105241908A CN105241908A CN201510543658.1A CN201510543658A CN105241908A CN 105241908 A CN105241908 A CN 105241908A CN 201510543658 A CN201510543658 A CN 201510543658A CN 105241908 A CN105241908 A CN 105241908A
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Abstract
The invention discloses an improved scanning method for a scanning probe microscope. In the method, in a forward scanning process which requires signal collection by the scanning probe microscope, interacting information of a probe to a sample is collected, and in a return scanning process which does not require signal collection, an improved return blank scanning control method is employed so that interaction between the probe and the sample is weakened or the probe and the sample are completely separated from each other. In the return scanning process, which does not require signal collection, of the scanning probe microscope, the interaction between the probe and the sample is weakened or the probe and the sample are completely separated from each other, so that invalid abrasion or consumption is effectively reduced or eliminated during the return scanning process. The method increases service life of a probe and also reduces use cost of a microscopy. The method can be widely used in the technical field of microscopy.
Description
Technical field
The present invention relates to technical field of microscopy, especially a kind of scanning probe microscopy scan method of improvement.
Background technology
After nineteen eighty-two scanning tunnel microscope STM occurs, develop again the similar Novel microscope of a series of activities principle successively, mainly comprise atomic force microscope, transverse force microscope LFM, magnetic force microscopy MFM, electrostatic force microscope EFM, Near-field Optical Microscope SNOM, piezoelectric forces microscope PFM, scan probe acoustics microscope SPAM etc., because they all utilize probe to scan sample, and need to obtain the relevant nature of sample (as pattern by the interaction (interaction force etc. as between sample-probe) of detector probe and sample in scanning process, friction force, domain structure etc.), thus they are collectively referred to as scanning probe microscopy SPM.Scanning probe microscopy scans sample surfaces by controlling probe, the synchronous interaction signal detecting and record probe and sample, thus obtains the surface information of sample, as shown in Figure 1.
Current scanline probe microscope all adopts probe to come and go scanning line by line to sample surfaces, and then forms a complete sample surfaces image by multiple scan line.In theory, microscopical control system is capable by controlling the specific region scanning n of probe to sample surfaces, and often row gathers the interaction signal of n point probe and sample, just can obtain the sample surface information of n × n the pixel in this region, as shown in Figure 2.
In fact, in order to reach nano level resolution, the scanning motion of scanning probe microscopy also must possess nano level control accuracy, therefore current scanning probe microscopy mostly adopts piezoelectric ceramic devices, realize probe by the driving voltage size controlling to be added to piezoelectric ceramics and the high precision of sample surfaces is scanned.But piezoelectric ceramics itself has lagging characteristics and creep properties, its motion state with except by Control of Voltage, also relevant to the change procedure (as change direction, speed etc.) of voltage, therefore it comes and goes movement locus of scanning and not exclusively coincidence.Even if adopt the motion of displacement transducer to piezoelectric ceramics to correct or realize the closed-loop control of motion, but be limited to the accuracy of detection of dynamic displacement sensor, many closed-loop control scanning probe microscopies with displacement transducer, also can close stance displacement sensor when high-resolution imaging among a small circle, with the form Direct driver scanning imagery of open loop.What is more important, during scanning probe microscopy scanning imagery, sample and needle point directly contact or closely (distance is 0.1 nanometer scale), there is stronger interaction and cause needle point to produce elastic deformation or distortion in needle point and sample room, because the interaction of needle point and sample changes with direction of scanning (i.e. probe motion direction) and sample surface morphology etc., needle point can produce different distortion or distortion in two direction of scanning of round scanning, also can cause probe and sample not overlapping at round scanning relative movement orbit.
For atomic force microscope most widely used in scanning probe microscopy, atomic force microscope passes through to detect the acting force imaging between sample and micro-cantilever probe tip, to obtain the surface topography of sample, as shown in Figure 3.When probe changes direction of scanning, the direction of the transverse force that needle point is subject to also changes thereupon, and therefore the direction of twist of probe is completely different, and this distortion is except relevant to direction of scanning, also relevant to the asymmetry of sample topography and probe.This distortion, can cause probe and sample not overlapping at the relative movement orbit of round scanning.In fact, even if be not other scanning probe microscopies of the acting force detecting sample and needle point, on nanoscale, because needle point and sample room height are close to the needle point stress and deformation phenomenon ubiquity caused.
For above-mentioned reasons, scanning probe microscopy is in the round both direction scanning process of probe, and the signal that can only gather one of them direction of scanning carries out imaging, as shown in Figure 4 (in figure, arrow represents direction of scanning).That is, in order to obtain the surface information image in sample appointed area with n × n pixel, probe needs this sector scanning 2n of sample surfaces capable, wherein, n is forward scan row (representing with solid line in Fig. 4), often row gathers the interaction signal of n point probe and sample, for system imaging; N, for returning scan line (being represented by dotted lines in Fig. 4), for the starting point making probe get back to next forward scan row, prepares to start forward scan next time.But scan probe microscopic probe is when returning scan line, still interacts with sample, creating invalid wearing and tearing, have impact on the serviceable life of probe, adding the use cost of instrument.
In sum, current scanning probe microscopy is in testing process, its control system can only gather the direction signal come and gone in scanning both direction and carry out imaging, and although another direction does not need collection signal, but its probe still interacts with sample, create invalid wearing and tearing, have impact on the serviceable life of probe, too increase microscopical use cost.
Summary of the invention
In order to solve the problems of the technologies described above, the object of the invention is: provide a kind of long service life and use cost low, the scanning probe microscopy scan method of improvement.
The technical solution adopted for the present invention to solve the technical problems is:
A kind of scanning probe microscopy scan method of improvement, scanning probe microscopy is in the interaction information of the forward scan process acquisition probe and sample that need collection signal, and do not needing the empty scan control method of backhaul that scanning process passes through improvement that returns of collection signal, make probe weaken with the interaction of sample room or probe is separated completely with sample.
Further, the empty scan control method of backhaul of described improvement is the empty scan control method of closed loop backhaul, the empty scan control method of described closed loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, change the setting reference point of scanning probe microscopy feedback control system, make feedback control system based on new reference point, exporting corresponding to determining the scanner vertical direction voltage that probe is elevated, making probe weaken with the interaction of sample room or probe is separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and the feedback control system of scanning probe microscopy recovers original reference point setting value, makes feedback control system get back to conventional sense, starts next forward scan line scanning.
Further, the empty scan control method of backhaul of described improvement is the empty scan control method of open loop backhaul, the empty scan control method of described open loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, turn off the feedback control system of scanning probe microscopy, by directly controlling, for determining the scanner vertical direction voltage that probe is elevated, to make probe weaken with the interaction of sample room or make probe be separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and reopens the feedback control system of scanning probe microscopy, makes feedback control system recover conventional sense, start next forward scan line scanning.
Further, the feedback control system of described scanning probe microscopy adopts PID analog feedback control system, and described PID analog feedback control system comprises:
Analog input end, for inputting the practical function force signal of probe and the sample room collected;
Reference point initialization circuit, for setting the force signals of reference point;
Subtraction circuit, generates for the force signals according to practical function force signal and reference point the error signal setting acting force and actual force;
Proportional amplifier, integrator and differentiator, carry out simulating signal calculation process for the error signal exported subtraction circuit;
Adder circuit, merges for signal proportional amplifier, integrator and differentiator exported, to export for determining the scanner vertical direction voltage signal that probe is elevated;
Two input ends of described subtraction circuit are connected with analog input end and reference point initialization circuit respectively, the output terminal of described subtraction circuit is connected with the input end of the input end of proportional amplifier, the input end of integrator and differentiator respectively, and the output terminal of described proportional amplifier, the output terminal of integrator are connected with three input ends of adder circuit respectively with the output terminal of differentiator.
Further, described reference point initialization circuit comprises:
First modulus conversion chip, for being converted to digital signal by the simulating signal of input;
First analog-digital chip, for regulating the acting force setting value of reference point;
First control module, for regulating the output of the first analog-digital chip;
The output terminal of described first modulus conversion chip is connected with the input end of the first analog-digital chip by the first control module, and the described output terminal of the first analog-digital chip is connected with the input end of subtraction circuit.
Further, described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the acting force setting value of the setting reference point of scanning probe microscopy feedback control system is changed by the cooperation of the first modulus conversion chip, the first control module and the first analog-digital chip, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
Further, also comprise sky scan reference point, switch-over control signal input end and analog switch, the input end of described analog switch is provided with the first switching point and the second switching point, described first switching point is connected with reference point initialization circuit, described second switching point is connected with empty scan reference point, the output terminal of described analog switch is connected with the input end of subtraction circuit, realizes the mutual switching between the first switching point and the second switching point under the switch-over control signal effect that described analog switch inputs at switch-over control signal input end.
Further, described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the mode switching to the second switching point by the first switching point by analog switch changes the acting force setting value of the setting reference point of scanning probe microscopy feedback control system, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
Further, the feedback control system of described scanning probe microscopy adopts digital feedback control system, and described digital feedback control system comprises:
Analog input end, for inputting the simulating signal of the actual force size of characterization probes and the sample room collected;
Second modulus conversion chip, for being converted to digital signal by the simulating signal of input;
Second control module, for calculating the difference of actual force and acting force setting value according to the digital signal after conversion, and generates for determining the digital voltage signal that probe is elevated according to the result calculated;
Second analog-digital chip, for by the digital voltage signal of generation being analog voltage signal output;
Described analog input end is connected with the second control module and then with the input end of the second analog-digital chip by the second modulus conversion chip successively.
Further, described second control module adopts central processing unit or digital signal processor.
The invention has the beneficial effects as follows: scanning probe microscopy returns scanning process what do not need acquisition probe and sample interaction information, probe is made to weaken with the interaction of sample room or probe is separated completely with sample, effectively can reduce or eliminate invalid wearing and tearing or the loss of retrace scanning process middle probe, add the serviceable life of probe, decrease microscopical use cost.Further, the empty scan control method of backhaul of the present invention both can adopt the empty scan control method of closed loop backhaul, also can adopt the empty scan control method of open loop backhaul, more flexibly.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described.
Fig. 1 is the structural representation of existing scanning probe microscopy;
Fig. 2 is the theoretical scanning pattern schematic diagram of existing scanning probe microscopy;
Fig. 3 is the Scan Architecture schematic diagram of existing atomic force microscope;
Fig. 4 is the actual scanning path schematic diagram of existing atomic force microscope;
Fig. 5 is the Scan Architecture schematic diagram of scanning probe microscopy of the present invention;
Fig. 6 is the structural representation of atomic force microscope of the present invention;
Fig. 7 is the system chart of PID analog feedback system of the present invention;
Fig. 8 is the structured flowchart of the adjustment initialization circuit of analog references of the present invention point;
Fig. 9 is the relation comparison diagram that embodiment of the present invention one scan driving voltage and reference point change;
Figure 10 is the system chart of digital feedback system of the present invention.
Reference numeral: 1, sample; 2, probe; 3, probe cantilevers; 4, laser instrument; 5, facula position detecting device; 6, incoming laser beam; 7, micro cantilever probe reflection lasering beam, 8, drive the piezoelectric ceramics that scans in X direction of probe, 9, the piezoelectric ceramics that drives probe scan along Y-direction, 10, the piezoelectric ceramics that moves along Z-direction of driving probe; 11, analog input end; 12, reference value initialization circuit; 13, subtraction circuit; 14, error signal; 15, proportional amplifier; 16, integrator; 17, differentiator; 18, adder circuit; 19, output signal; 22, the second modulus conversion chip; 23, the second control module; 24, the second analog-digital chip; 33, the empty scan reference point of backhaul; 34, analog switch; 35, switch-over control signal input end.
Embodiment
With reference to Fig. 5, a kind of scanning probe microscopy scan method of improvement, scanning probe microscopy is in the interaction information of the forward scan process acquisition probe and sample that need collection signal, and do not needing the empty scan control method of backhaul that scanning process passes through improvement that returns of collection signal, make probe weaken with the interaction of sample room or probe is separated completely with sample.
Be further used as preferred embodiment, the empty scan control method of backhaul of described improvement is the empty scan control method of closed loop backhaul, the empty scan control method of described closed loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, change the setting reference point of scanning probe microscopy feedback control system, make feedback control system based on new reference point, exporting corresponding to determining the scanner vertical direction voltage that probe is elevated, making probe weaken with the interaction of sample room or probe is separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and the feedback control system of scanning probe microscopy recovers original reference point setting value, makes feedback control system get back to conventional sense, starts next forward scan line scanning.
Wherein, forward scan row with return scan line and divide according to the interaction information the need of acquisition probe and sample, forward scan row needs the interaction information of acquisition probe and sample, returns the interaction information that scan line does not need acquisition probe and sample.
Be further used as preferred embodiment, the empty scan control method of backhaul of described improvement is the empty scan control method of open loop backhaul, the empty scan control method of described open loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, turn off the feedback control system of scanning probe microscopy, by directly controlling, for determining the scanner vertical direction voltage that probe is elevated, to make probe weaken with the interaction of sample room or make probe be separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and reopens the feedback control system of scanning probe microscopy, makes feedback control system recover conventional sense, start next forward scan line scanning.
Wherein, forward scan row with return scan line and divide according to the interaction information the need of acquisition probe and sample, forward scan row needs the interaction information of acquisition probe and sample, returns the interaction information that scan line does not need acquisition probe and sample.
With reference to Fig. 7, be further used as preferred embodiment, the feedback control system of described scanning probe microscopy adopts PID analog feedback control system, and described PID analog feedback control system comprises:
Analog input end, for inputting the practical function force signal of probe and the sample room collected;
Reference point initialization circuit, for setting the force signals of reference point;
Subtraction circuit, generates for the force signals according to practical function force signal and reference point the error signal setting acting force and actual force;
Proportional amplifier, integrator and differentiator, carry out simulating signal calculation process for the error signal exported subtraction circuit;
Adder circuit, merges for signal proportional amplifier, integrator and differentiator exported, to export for determining the scanner vertical direction voltage signal that probe is elevated;
Two input ends of described subtraction circuit are connected with analog input end and reference point initialization circuit respectively, the output terminal of described subtraction circuit is connected with the input end of the input end of proportional amplifier, the input end of integrator and differentiator respectively, and the output terminal of described proportional amplifier, the output terminal of integrator are connected with three input ends of adder circuit respectively with the output terminal of differentiator.
Be further used as preferred embodiment, described reference point initialization circuit comprises:
First modulus conversion chip, for being converted to digital signal by the simulating signal of input;
First analog-digital chip, for regulating the acting force setting value of reference point;
First control module, for regulating the output of the first analog-digital chip;
The output terminal of described first modulus conversion chip is connected with the input end of the first analog-digital chip by the first control module, and the described output terminal of the first analog-digital chip is connected with the input end of subtraction circuit.
Wherein, the first control module can adopt central processing unit or digital signal processor.
Be further used as preferred embodiment, described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the acting force setting value of the setting reference point of scanning probe microscopy feedback control system is changed by the cooperation of the first modulus conversion chip, the first control module and the first analog-digital chip, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
With reference to Fig. 8, be further used as preferred embodiment, also comprise sky scan reference point, switch-over control signal input end and analog switch, the input end of described analog switch is provided with the first switching point and the second switching point, described first switching point is connected with reference point initialization circuit, described second switching point is connected with empty scan reference point, the output terminal of described analog switch is connected with the input end of subtraction circuit, realizes the mutual switching between the first switching point and the second switching point under the switch-over control signal effect that described analog switch inputs at switch-over control signal input end.
Be further used as preferred embodiment, described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the mode switching to the second switching point by the first switching point by analog switch changes the acting force setting value of the setting reference point of scanning probe microscopy feedback control system, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
With reference to Figure 10, be further used as preferred embodiment, the feedback control system of described scanning probe microscopy adopts digital feedback control system, and described digital feedback control system comprises:
Analog input end, for inputting the simulating signal of the actual force size of characterization probes and the sample room collected;
Second modulus conversion chip, for being converted to digital signal by the simulating signal of input;
Second control module, for calculating the difference of actual force and acting force setting value according to the digital signal after conversion, and generates for determining the digital voltage signal that probe is elevated according to the result calculated;
Second analog-digital chip, for by the digital voltage signal of generation being analog voltage signal output;
Described analog input end is connected with the second control module and then with the input end of the second analog-digital chip by the second modulus conversion chip successively.
Be further used as preferred embodiment, described second control module adopts central processing unit or digital signal processor.
Below in conjunction with Figure of description and specific embodiment, the present invention is described in further detail.
Embodiment one
The scanning probe microscopy of the present embodiment is when scanning probe microscopy is detected as picture, return in scanning pattern at probe, control probe and sample separation, then after return to origin, probe and sample contacts is controlled again, start the forward scan of next line, as shown in Figure 5 (solid line is forward scan track, and dotted line is for returning track while scan).
As can be seen from Figure 5, when being detected as picture, scanning probe microscopy makes probe and sample separation in the sweep retrace once coming and going scanning process, effectively eliminates invalid wearing and tearing or the loss of needle point, also reduce needle point by the probability of sample contamination, improve the serviceable life of probe.
The present embodiment, for atomic force microscope, is described implementation procedure of the present invention.
As shown in Figure 6, atomic force microscope (is generally 10 by the micro force detecting needle point and sample room
-9 the acting force of N magnitude) obtain the surface topography of sample.The probe of this atomic force microscope is the micro-cantilever of a front end with nanoscale acutance needle point, the incoming laser beam 6 that laser instrument 4 is launched gets to the front end of semi-girder, and the reflection lasering beam 7 that incoming laser beam 6 produces through semi-girder reflection incides facula position detecting device 5.Facula position detecting device 5 changes the movement of hot spot into electric signal, and obviously the change of this electric signal just reflects the bending change of micro-cantilever and the change of needle point and sample room acting force.In scanning process, the control system of atomic force microscope is passed through to export specific voltage signal by scan drive circuit, drive the piezoelectric ceramics 8 and 9 along X, Y-direction scanning, control probe to scan at sample surfaces, the feedback control system of atomic force microscope then detects in real time to the output signal of facula position detecting device 5, and drive the piezoelectric ceramics 10 along Z-direction to stretch by the output voltage signal of feedback control system, the oscilaltion of automatic control probe, to offset the fluctuating of sample surfaces, makes the acting force of probe and sample room keep constant.
Wherein, the feedback control system principle of work of atomic force microscope is: control system sets the target (i.e. the reference point of feedback control system) of acting force as FEEDBACK CONTROL of a needle point and sample room, when the actual force (being detected by the output signal of facula position detecting device 5) of needle point and sample room is greater than reference point, feedback control system will reduce output voltage automatically, drive the piezoelectric ceramics 10 along Z-direction to shrink, allow probe promote with the acting force reducing needle point and sample; Otherwise when actual force is less than reference point, feedback control system will increase output voltage automatically, drive the piezoelectric ceramics 10 along Z-direction to extend, and allow probe decline with the acting force increasing needle point and sample.
(return in scanning pattern namely at probe to realize the empty scan control method of backhaul that the present invention proposes, make control needle point and sample separation), as long as in fact the control system of atomic force microscope accomplishes: when scan drive circuit exports the voltage of sweep retrace, synchronous reduction is owing to driving the voltage of the piezoelectric ceramics 10 of probe lifting, needle point is raised, with sample separation; And complete in backhaul, start next line scanning before, recover normal FEEDBACK CONTROL.
Early stage atomic force microscope adopts analog feedback control system, along with Digital Signal Processing development, digital feedback control system is more convenient and flexible owing to having, feedback policy can be changed at any time and the advantage of feedback algorithm of various advanced person can be realized, substitute the main flow that analog feedback system becomes atomic force microscope gradually at present.Realize concrete scheme of the present invention to employing analog feedback control system and these two kinds of structures of digital feedback control system respectively to be below described.
(1) analog feedback control system
Analog feedback control system of the present invention adopts traditional proportional-integral-differential (PID, ProportionIntegrationDifferentiation) controller, and its system chart as shown in Figure 7.
Wherein, the acting force of needle point and sample is converted to electric signal by folded light beam deflection mechanism and facula position detecting device, is input to by subtraction circuit 13 together with the signal of reference point initialization circuit, obtains the error signal 14 setting acting force and actual force; After this error signal carries out simulating signal calculation process respectively through proportional amplifier 15, integrator 16 and differentiator 17, again after totalizer 18 merges, export the output signal 19 for driving piezoelectric ceramics 10 to regulate probe to be elevated, this output signal 19 affects again the acting force of needle point and sample conversely, define a closed feedback loop, finally make the acting force of needle point and sample equal the reference value (namely error signal 14 is 0) of default.In this backfeed loop, integrator is for improving the control accuracy of feedback system, and differentiator is for accelerating the transient process of feedback system and improving dynamic response.
For analog feedback control system, its output voltage is the result of simulation trial, in order to make needle point and sample separation, and can by realizing in the setting value returning scanning process change reference point.Because reference point determines the FEEDBACK CONTROL target of needle point and sample room acting force, therefore, if reduce the settings of reference point, feedback control system will reduce output voltage, probe is raised, until needle point and the acting force of sample room be reduced to consistent with new reference point acting force till.In extreme situations, if change into negative with reference to point, as long as its absolute value is greater than the absorption affinity of probe and sample, this feedback system will reduce output voltage fast, probe is mentioned rapidly, and now the repulsive force status transition by normal imaging is also finally made probe and sample separation to absorption affinity state by the acting force of needle point and sample.
Wherein, the adjustment setting means of the reference point of analog feedback control system has two kinds, a kind of employing analog-digital chip DAC, the analog quantity exported by software control is to adjust setting, and another kind is that user directly adjusts setting by the analog switch being arranged on microscopy instrument panel.
For the first form, the empty scan control method of backhaul implements very convenient, as long as revise slightly the software of the first control module, the output quantity of synchronous change first analog-digital chip when exporting the driving voltage of sweep retrace, the relation that the driving voltage now scanned and reference point change as shown in Figure 9.Wherein, V
xfor driving the voltage swing that scans in X direction of probe, wherein, solid line represents and drives the voltage that probe carries out the voltage of forward scan line scanning, dotted line represents retrace scanning; V
yfor the voltage pattern driving probe to scan along Y-direction, as can be seen from Figure 9, the driving voltage of X-direction often completes a forward scan, and the driving voltage of Y-direction all can reduce a gear, moves to next line to control probe.And the reference point size that S0 is system when being normally detected as picture, represent with solid line; S1 is the reference point size of the empty scanning process of backhaul, represents with dotted line; During scanning, microscopical control system controls reference point periodically-varied between S0 and S1, and with forward scan row and retrace scanning stringent synchronization, to realize the scanning of backhaul sky.
For the second form, because analog switch can not rapid adjustment and not by software control, therefore it cannot be synchronous with scan control, but in fact only need transform the reference point initialization circuit of feedback control system and corresponding control software design, can realize the empty scan control of backhaul equally, concrete realizes structure as shown in Figure 8.In fact, only need increase a switching analoging switch 34 between the original reference point initialization circuit 12 of Fig. 7 and subtraction circuit 13, and another input of this change-over switch be received the empty scan reference point 33 of backhaul promoted for controlling needle point.Which control system, in the original reference point of system and these two reference point signals of empty scan reference point, selects work by switch-over control signal input end 35.Therefore, only need be switched to sky scan reference point by synchro control analog switch 34 when exporting the driving voltage of sweep retrace, the empty scan function of backhaul can be realized.
As can be seen from above analysis, the interaction force of needle point and sample is by feedback control system closed-loop control, so by returning in scanning pattern the settings changing reference point, both the acting force of needle point and sample can have been reduced, also needle point can be made to be separated completely with sample, to reach the object reducing or eliminating the invalid loss of needle point.Due in said method, feedback control system is playing control action always, and therefore the method is called the empty scan control method of closed loop backhaul by the present invention.
(2) digital feedback control system
Digital feedback control system adopts the software algorithm of central processing unit (CPU) or digital signal processor (DSP) to realize FEEDBACK CONTROL, and its system chart as shown in Figure 10.
The function of digital feedback control system is similar to analog feedback control system, the simulating signal of the amount of force characterizing needle point and sample is first converted to digital quantity by the second modulus conversion chip 22 by feedback control system, software algorithm is adopted to calculate the error of digital quantity and acting force setting value in real time by the second control module 23 again, feedback policy (comprising classical proportional integral differential control and more complicated FEEDBACK CONTROL), finally digital operation result is converted to analog voltage by the second D/A converting circuit 24 to export, piezoelectric ceramics 10 is driven to regulate the lifting of probe, to form a closed feedback loop.
For digital feedback system, due to the software algorithm that feedback core is a set of embedding, reference point in fact also belongs to a variable in algorithm software, therefore the empty scanning technique of closed loop backhaul realize very convenient, as long as revise corresponding embedded software, this variable of reference point is changed synchronous with the driving voltage exporting sweep retrace.
Digital feedback system realizes the empty scanning technique of backhaul and also has the more simple method of one, be exactly while the driving voltage exporting sweep retrace, digital feedback algorithm out of service (be equivalent to cut and turn off feedback control loop), directly outputting drive voltage is set to minimum value, now probe rises, needle point and sample separation.Due in said method, during sweep retrace, feedback control loop can be cut off, and feedback control system is in open loop situations, and therefore the method is called the empty scan control method of open loop backhaul by the present invention.
In addition, the empty scan control method of closed loop backhaul is all applicable to analog-and digital-feedback control system, both needle point and sample separation can be controlled in sweep retrace, also the interaction of needle point and sample is just weakened by selecting suitable reference point to make needle point not exclusively be separated with sample, the same object that can realize the loss of minimizing probe, in this case, the conversion be periodically separated with sample room owing to there is not needle point between forward scan with sweep retrace, contacted and the situation of impact, system has the more stable advantage of state.And the empty scan control method of open loop backhaul feedback control loop when sweep retrace can be cut off, it is only applicable to digital feedback system, but has the simple advantage of implementation method.
Compared with prior art, each probe microscopical for conventional scanning probe is come and gone scan line and is divided into forward scan row by the interaction information the need of acquisition probe and sample room and returns scan line by the present invention, and do not needing the sweep retrace of interaction information of acquisition probe and sample room, probe is made to weaken with the interaction of sample room or probe is separated completely with sample, invalid wearing and tearing or the loss of probe can be reduced or eliminated, increase the serviceable life of probe.And the present invention to the wearing quality of probe without particular/special requirement, no matter be average probe or wear-resisting probe, as long as it adopts method of the present invention, all can significantly improve its serviceable life.
More than that better enforcement of the present invention is illustrated, but the invention is not limited to described embodiment, those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite without prejudice to spirit of the present invention, and these equivalent distortion or replacement are all included in the application's claim limited range.
Claims (10)
1. the scanning probe microscopy scan method improved, it is characterized in that: scanning probe microscopy is in the interaction information of the forward scan process acquisition probe and sample that need collection signal, and do not needing the empty scan control method of backhaul that scanning process passes through improvement that returns of collection signal, make probe weaken with the interaction of sample room or probe is separated completely with sample.
2. the scanning probe microscopy scan method of a kind of improvement according to claim 1, is characterized in that: the empty scan control method of backhaul of described improvement is the empty scan control method of closed loop backhaul, the empty scan control method of described closed loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, change the setting reference point of scanning probe microscopy feedback control system, make feedback control system based on new reference point, exporting corresponding to determining the scanner vertical direction voltage that probe is elevated, making probe weaken with the interaction of sample room or probe is separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and the feedback control system of scanning probe microscopy recovers original reference point setting value, makes feedback control system get back to conventional sense, starts next forward scan line scanning.
3. the scanning probe microscopy scan method of a kind of improvement according to claim 1, is characterized in that: the empty scan control method of backhaul of described improvement is the empty scan control method of open loop backhaul, the empty scan control method of described open loop backhaul, and it is specially:
Scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, turn off the feedback control system of scanning probe microscopy, by directly controlling, for determining the scanner vertical direction voltage that probe is elevated, to make probe weaken with the interaction of sample room or make probe be separated completely with sample; Returning the scan line end of scan, forward scan line scanning is when starting, and reopens the feedback control system of scanning probe microscopy, makes feedback control system recover conventional sense, start next forward scan line scanning.
4. the scanning probe microscopy scan method of a kind of improvement according to claim 2, is characterized in that: the feedback control system of described scanning probe microscopy adopts PID analog feedback control system, and described PID analog feedback control system comprises:
Analog input end, for inputting the practical function force signal of probe and the sample room collected;
Reference point initialization circuit, for setting the force signals of reference point;
Subtraction circuit, generates for the force signals according to practical function force signal and reference point the error signal setting acting force and actual force;
Proportional amplifier, integrator and differentiator, carry out simulating signal calculation process for the error signal exported subtraction circuit;
Adder circuit, merges for signal proportional amplifier, integrator and differentiator exported, to export for determining the scanner vertical direction voltage signal that probe is elevated;
Two input ends of described subtraction circuit are connected with analog input end and reference point initialization circuit respectively, the output terminal of described subtraction circuit is connected with the input end of the input end of proportional amplifier, the input end of integrator and differentiator respectively, and the output terminal of described proportional amplifier, the output terminal of integrator are connected with three input ends of adder circuit respectively with the output terminal of differentiator.
5. the scanning probe microscopy scan method of a kind of improvement according to claim 4, is characterized in that: described reference point initialization circuit comprises:
First modulus conversion chip, for being converted to digital signal by the simulating signal of input;
First analog-digital chip, for regulating the acting force setting value of reference point;
First control module, for regulating the output of the first analog-digital chip;
The output terminal of described first modulus conversion chip is connected with the input end of the first analog-digital chip by the first control module, and the described output terminal of the first analog-digital chip is connected with the input end of subtraction circuit.
6. the scanning probe microscopy scan method of a kind of improvement according to claim 5, it is characterized in that: described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the acting force setting value of the setting reference point of scanning probe microscopy feedback control system is changed by the cooperation of the first modulus conversion chip, the first control module and the first analog-digital chip, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
7. the scanning probe microscopy scan method of a kind of improvement according to claim 4, it is characterized in that: also comprise sky scan reference point, switch-over control signal input end and analog switch, the input end of described analog switch is provided with the first switching point and the second switching point, described first switching point is connected with reference point initialization circuit, described second switching point is connected with empty scan reference point, the output terminal of described analog switch is connected with the input end of subtraction circuit, the mutual switching between the first switching point and the second switching point is realized under the switch-over control signal effect that described analog switch inputs at switch-over control signal input end.
8. the scanning probe microscopy scan method of a kind of improvement according to claim 7, it is characterized in that: described scanning probe microscopy terminates in forward scan line scanning, return scan line scanning start time, the mode switching to the second switching point by the first switching point by analog switch changes the acting force setting value of the setting reference point of scanning probe microscopy feedback control system, to reduce the scanner vertical direction voltage that feedback control system exports, and then probe is made to weaken with the interaction of sample room or probe is separated completely with sample.
9. the scanning probe microscopy scan method of a kind of improvement according to Claims 2 or 3, is characterized in that: the feedback control system of described scanning probe microscopy adopts digital feedback control system, and described digital feedback control system comprises:
Analog input end, for inputting the simulating signal of the actual force size of characterization probes and the sample room collected;
Second modulus conversion chip, for being converted to digital signal by the simulating signal of input;
Second control module, for calculating the difference of actual force and acting force setting value according to the digital signal after conversion, and generates for determining the digital voltage signal that probe is elevated according to the result calculated;
Second analog-digital chip, for by the digital voltage signal of generation being analog voltage signal output;
Described analog input end is connected with the second control module and then with the input end of the second analog-digital chip by the second modulus conversion chip successively.
10. the scanning probe microscopy scan method of a kind of improvement according to claim 9, is characterized in that: described second control module adopts central processing unit or digital signal processor.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109219752A (en) * | 2016-06-02 | 2019-01-15 | 株式会社岛津制作所 | Scanning type probe microscope |
| CN110018332A (en) * | 2019-04-30 | 2019-07-16 | 长春理工大学 | A kind of compensation method of atomic force probe contact type scanning imaging biological cells error |
| CN110095491A (en) * | 2019-05-09 | 2019-08-06 | 上海华力微电子有限公司 | A kind of defect detecting system, detection method and electron beam scanning machine |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5162653A (en) * | 1988-06-02 | 1992-11-10 | Hitachi, Ltd. | Scanning tunneling microscope and surface topographic observation method |
| US5412980A (en) * | 1992-08-07 | 1995-05-09 | Digital Instruments, Inc. | Tapping atomic force microscope |
| EP1482297A1 (en) * | 2002-02-05 | 2004-12-01 | Riken | Scanning probe microscope and specimen surface structure measuring method |
| CN1912573A (en) * | 2005-08-08 | 2007-02-14 | 中国科学院电工研究所 | Digital closed-loop scanning control system of scanning probe microscope |
| CN201828788U (en) * | 2010-10-08 | 2011-05-11 | 北京电子科技职业学院 | Automatic dissolved oxygen measuring and controlling system and aerobic organism treatment equipment |
| US20110167524A1 (en) * | 2008-11-13 | 2011-07-07 | Bruker Nano, Inc. | Method and apparatus of operating a scanning probe microscope |
| CN102272610A (en) * | 2008-12-11 | 2011-12-07 | 因菲尼泰西马有限公司 | Dynamic probe detection system |
-
2015
- 2015-08-28 CN CN201510543658.1A patent/CN105241908A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5162653A (en) * | 1988-06-02 | 1992-11-10 | Hitachi, Ltd. | Scanning tunneling microscope and surface topographic observation method |
| US5412980A (en) * | 1992-08-07 | 1995-05-09 | Digital Instruments, Inc. | Tapping atomic force microscope |
| EP1482297A1 (en) * | 2002-02-05 | 2004-12-01 | Riken | Scanning probe microscope and specimen surface structure measuring method |
| CN1912573A (en) * | 2005-08-08 | 2007-02-14 | 中国科学院电工研究所 | Digital closed-loop scanning control system of scanning probe microscope |
| US20110167524A1 (en) * | 2008-11-13 | 2011-07-07 | Bruker Nano, Inc. | Method and apparatus of operating a scanning probe microscope |
| CN102272610A (en) * | 2008-12-11 | 2011-12-07 | 因菲尼泰西马有限公司 | Dynamic probe detection system |
| CN201828788U (en) * | 2010-10-08 | 2011-05-11 | 北京电子科技职业学院 | Automatic dissolved oxygen measuring and controlling system and aerobic organism treatment equipment |
Non-Patent Citations (2)
| Title |
|---|
| 李宝河等: "《高磁晶各向异性磁记录薄膜材料》", 30 June 2012, 第110-112页 * |
| 蒋士亮: "《物理学与高技术前言》", 30 September 2006, 广西民族出版社 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109219752A (en) * | 2016-06-02 | 2019-01-15 | 株式会社岛津制作所 | Scanning type probe microscope |
| CN109219752B (en) * | 2016-06-02 | 2021-06-11 | 株式会社岛津制作所 | Scanning probe microscope |
| CN110018332A (en) * | 2019-04-30 | 2019-07-16 | 长春理工大学 | A kind of compensation method of atomic force probe contact type scanning imaging biological cells error |
| CN110018332B (en) * | 2019-04-30 | 2021-08-06 | 长春理工大学 | Atomic force probe contact type scanning biological cell imaging error compensation method |
| CN110095491A (en) * | 2019-05-09 | 2019-08-06 | 上海华力微电子有限公司 | A kind of defect detecting system, detection method and electron beam scanning machine |
| CN110095491B (en) * | 2019-05-09 | 2021-08-20 | 上海华力微电子有限公司 | Defect detection system, defect detection method and electron beam scanning machine |
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