Interferograms analysis for measuring the thickness of aluminum thin films

Abstract

In this work, a specific procedure to measure the thickness of aluminum thin films by interferogram analysis is described. Six interferograms correspond to the image of the aluminum thin film superimposed with interference fringes are obtained from a Michelson-type interferential microscope. A six-frame phase shift algorithm is used to demodulate the optical phase. The measured phase is proportional to the height variation between the thin film wafer and the substrate. Finally, the obtained 3D height map permits us measure the thickness of the sample over an area of 1024 μm × 1280 μm.