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Study on Characterization Methods of Tip Radius of AFM Worn Probe

AFM has a wide range of applications in scanning imaging and manufacturing of nanostructures. AFM probes often wear during the use of AFM, and the change of tip morphology will inevitably affect the accuracy of AFM measurement and processing. Therefore, it is necessary to characterize the morphology of AFM probe with wear. Since the tip size of AFM probe is nanoscale, traditional measurement methods cannot be used for observation, and the current common AFM tip morphology characterization methods are difficult to simultaneously meet the accuracy and convenience of measurement. In this paper, a method to characterize the tip radius of AFM worn probe was proposed. Nanoindentation operation was carried out on soft PVC sheet with worn probe, and Hertz model fitting was performed on the collected indentation loading curve to obtain the tip radius. In this paper, the elastic deformation depth of soft PVC sheet nanoindentation point is determined to be about 30 nm by finite element simulation, which is convenient for Hertz model fitting of elastic deformation segment of indentation loading curve in the follow-up. The AFM probe with different wear degree was measured by this characterization method, and the feasibility of this characterization model was verified based on SEM measurement results, and the scope of application of this characterization model was also proposed. This characterization method can realize the in-situ measurement of tip radius of AFM worn probe, and the tip will not be further worn during the measurement process, which can realize the accuracy and convenience of AFM tip measurement.