Simultaneous measurement of surface geometry and film thickness distribution by retroreflex ellipsometry

A holistic approach to determine the surface orientation and film thickness for nonplanar isotropic three-phase systems (ambient-film-substrate) by retroreflex ellipsometry is presented. After scanning the surface of the sample, the ellipsometric parameters (Ψ, Δ), the surface orientation (θ 0 , ϕ) and the film thickness d can be measured simultaneously. Then, the surface geometry can be reconstructed by numerical gradient integration. The influence of the spot size and incident angle on the measurement results is simulated and discussed. The experiments show satisfactory results for film thickness distribution and surface geometry, which prove that the method is capable of measuring nonplanar surfaces.