A Scanning White-Light Interferometric Profilometer for Smooth and Rough Surface

A profilometer for micro-surface topography measurement is presented. The instrument is based on the scanning white-light microscopic interferometry (SWLMI). A Linnik type interference microscope is used and the interferograms which present changes of surface profile are recorded by a CCD camera. A developed nano-positioning work stage with integrated optical grating displacement measuring system realizes the precise vertical scanning motion during profile measurement. By white-light phase shifting algorism of arbitrary steps, frames of interferograms are processed by computer to rebuild and evaluate the measured profile. Because of the specialty of SWLMI, the profilometer is suitable for both smooth and rough surface measuring. It also can be used for the measurement of curved surface, dimension of MEMS etc. The vertical resolution of the profilometer is 0.5nm, lateral resolution 0.5+m.