Epi‐Illumination Spatio‐Temporal Scanning Interference Microscopy for 3D Topography Measurement With an Unlimited Field‐of‐View

ABSTRACT The limited field of view (FoV) of conventional interferometric imaging techniques is hard‐pressed to meet the demand for high‐throughput characterization of large‐scale micro‐ and nanostructures. To mitigate these challenges, we developed an epi‐illumination spatio‐temporal scanning interference microscope (epi‐STSIM) with an extended FoV along the scanning direction, which avoids the trade‐off between the resolution and FoV. The recorded interferograms of epi‐STSIM are processed by the proposed non‐iterative generalized phase‐shifting algorithm (PSA) combined with Lissajous ellipse fitting and least‐squares sine fitting (LEF&LSF). We demonstrate the resistance to environmental vibration and straightness error, and the height measurement accuracy comparable to vertical scanning white light interferometry (WLI). The measurement results of a microlens array and an etched nanostructure verify the feasibility of large‐scale micro‐ and nanostructure topography measurement.