Nanometrology based on white-light spectral interferometry in thickness measurement

Abstract

A new white-light interferometric technique using in measurement of thickness based on the theory of spectral-domain interference is specified in the paper. The theory of spectral-domain interference broke the limitation of coherence length in interferometry, and gain a much longer measuring range than in time-domain. The optical fiber was applied to Michelson interferometer with the advantage of much convenience of system design. Spectrometer is used to get the spectral-domain signal. With a simple arithmetic, the optical path difference which is related to some parameter could be acquired. A thickness measuring system is designed. The measuring range could be calculated, the error could be forecasted. The simulated result indicats the error of white-light spectral interferometry can be controlled within several nanometers.