Miniaturized Optical Measurement Methods for Surface Nanometrology

This paper introduces some new types of optical surface measurement methods. One method uses spatial light-wave scanning to replace mechanical stylus scanning, and an optical fibre interferometer to replace optically bulky interferometers either of which are involved in almost all current surface measurement (stylus and optical) methods. The optical principle is based on measuring the phase shift of light reflected from the surface by using a combination of Wavelength/Frequency-Division-Multiplexing (WDM or FDM) and Fibre Bragg Grating (FBG) techniques. The WDM/FDM-FBG techniques provide the implementation of phase-to-depth and wavelength-to-field detection, and can offer a large dynamic measurement ratio (range/resolution) with a high signal-to-noise ratio (robustness).