Development of Transparent Film Thickness Measurement System by Three-wavelength Interference Method

-Extension of Global Model Fitting Algorithm-

Abstract

Conventional transparent film thickness measurement methods such as spectroscopy acquire basically a single measurement point at a time, and the spatial resolution is limited. We have developed a novel areal film thickness measurement system by extending the Global Model Fitting algorithm developed for three-wavelength interferometric surface profiling. It estimates the film thickness distribution from a color image captured by a color camera and three-wavelength light source. The key features are: (1) high spatial resolution, (2) high-speed measurement, (3) low cost and simple optics, and (4) no preliminary calibration required.