Theory And Technology Study On Mems Based Probe-array Head Of SPM

Almost soon after the invention of the scanning probe microscopy (SPM), itattracted widespread attentions and quickly found its applications invarious scientificdisciplines and industrial fields with its sub-nanometer resolution andmicro-nanoscale manipulation. In spite of their achived successes regardingmeasurement resolution and accuracy, traditional SPMs embody such unsurmountabledisadvantages like relatively low imaging speed and narrow scan range. To improvethe imaging efficiency, novel probe-array SPM head based on MEMS comb structureis developed. Meanwhile, probe-array SPM including probe-array SPM head andNano Measuring Machine is developed to complish multi-probe imaging. Mainachievements of this research work are the following:1. The theoretical model of mechanical structure of a novel MEMS basedprobe-array SPM head is analyzed. Based on material theory, the equation of3Dspring constant is deduced. According to the influence degree of structure andparameters of beam, optimum structure and parameters are chosen. Finite elementsimulated data of optimum structure are compared and validated with the conclusionof theoretical analysis.3D spring constants of the structure are optimum configured toensure the stability of the probe-array SPM head.2. Based on electinics features and electrical model, the nonlinearity influence oftranslation and rotation of the main shaft, which is induced by friction and shear forceapplied on the probe along Y and Z axis in the scanning process, is analyzed. Pull-inand levitation force generated by electrostatic field is analyzed. With above twoanalyses, the scanning routine direction, scanning travel limit and applied voltagelimit is determined.3. As the first time application of this kind of structure, the operating mode of theSPM head is analyzed. According to the traditional AFM operating mode, three kindsof operating mode is proposed as height constant mode, force constant mode anddynamic mode. After comparing three kinds of operating mode, force constant modeis chosen as main operating mode in our experiment. 4. Spring constant along the measurement axis is to be calibrated to keep forceconstant mode stable. A quick and traceable method including Nano MeasuringMachine and ultra-precision balace is proposed and complished.5. Through the combination of probe-array SPM head and Nano MeasuringMachine positioning platform, probe-array SPM is constructed. The measurementdata is traceable though three embedded laser interferometers. Experiments are carriedout to calibrate the sensitivity, hysteresis, repeatability, resolution and dynamiccharacteristics of the SPM probe. A series of standard samples are measured. Theresults demonstrated the system’s nanometer magnitude resolution and lare rangemeasurement capability.