High resolution imaging microellipsometry of soft surfaces at 3 μm lateral and 5 Å normal resolution

We report on the design of an imaging microellipsometer enabling the generation of maps of the two ellipsometric angles Δ and Ψ. Areas of 60×200 μm2 are imaged at a rate of 1–2 images per minute. By working at angles (45°) much smaller than the Brewster angle (≈73° for Si/SiO2/air) a lateral resolution of 3 μm and a height resolution of 5 Å is achieved. The performance is demonstrated by thickness measurement of a laterally structured polymer film and a transient thickness measurement of dewetting fluid film of n-hexadecane on a Si/SiO2 wafer.