Single-shot characterization of multi-film structures based on combined spectral interferometry and spatially...

In this investigation, we propose an improved combined scheme with spectral interferometry and spatially recorded spectroscopic ellipsometry to measure surface height and film thicknesses at once in real time. Instead of rotating polarizing optical components, a spatial phase retarder, which consists of spatially rotating liquid crystal arrays, is used to obtain the ellipsometric spectral data from a single image. In addition, interferometric configuration is combined to collect the surface height information in the same image. The spatial phase retarder can be characterized by the phase retardation and the rotation angle of the liquid crystal during the calibration procedure. In the experiments, single-layered and multi-layered film specimens were measured to verify the measurement capability of the proposed system, and it was confirmed that the measurement results were in good agreement with the provided reference values.