Optical topometry of surfaces with locally changing materials, layers and contaminations Part 2: Fringe projection topometry

Abstract

Conventional topometry evaluation procedures applied to surfaces with locally changing materials or layer structures can result in significant errors in the topometric heights. A new theoretical approach, developed for two-beam interferometry in part 1, is now applied to fringe projection topometry, where the oblique incidence of two or three partial plane-wave components has to be considered. Important effects of contrast and phase are presented and applied to some surface structures, and errors in the measured surface height are calculated.