Measurement Method of RMS Roughness and Autocorrelation Function of Super Smooth Surface using Shearing Interference Microscope

Abstract

A shearing interference microscope has high image stability even under vibration. This paper proposes a measurement method of RMS roughness and autocorrelation function of super smooth surfaces using shearing interference microscopic images. It makes use of the fact that, when the shearing length is extended widely in comparison to the autocorrelation length of the rough surface, the shearing interference image comes in close relationship with the RMS roughness of the measuring surface. Herein are shown a principle and a theory as well as a result of measurements of super smooth surfaces of 2 nm-10 nm RMS roughness.