Influence of probe dynamic characteristics on the scanning speed for white light interference based AFM

The dynamic characteristics of an atomic force probe are important for rapid and accurate measurement in white light interference (WLI) based atomic force microscope (AFM). The tip of the probe will fly from the surface when its dynamic characteristics are poor, which will cause measurement error. Generally such tip flight can be avoided by reducing the scanning speed, which will decrease the error at the cost of measurement efficiency. In this paper, a dynamical model of atomic force probe is presented to analyze the causes of tip flight in the measurement process. A numerical simulation is performed on a typical sample surface to investigate the influence of profile, preloading and probe parameters on scanning speed. Experimental testing is conducted on a self-developed WLI based AFM, and the experimental results agree well with that of the theory. The maximum scanning speeds of the probe for a sample are tested under certain conditions. It is shown that for a certain probe, the tip flight occurs at the upwards points of the measured sample when the scanning speed exceeds the critical speed, which is constrained by the preloading.