Microscopic 3D structural inversion technique for multilevel periodic structures with SEM moiré method

This communication proposes a novel 3D SEM moiré technique to apply to the inversion/reconstruction for micro objects with periodic structures on the surface. A revised geometric model was theoretically developed to enhance the accuracy and to simplify the calculation. Combined with the random phase-shifting technique, a theoretical relative uncertainty of 2.31% was realized, which was confirmed through a digital simulation. We selected the reflecting grating as a typical sample in the experiments, and auxiliary microscopic equipment was employed to evaluate the results from the proposed method. The measurement result agrees well with the results obtained from an atomic force microscope (AFM), and the experiments validate the feasibility of the method.