Characterization of the Binary Micro-Grating Surface by Scanning White Light Interferometry

We used scanning white-light interferometry(SWLI) for surface morphology characterization of binary micro-grating. The 3-D surface topography of specimen was rebuilt using cosine Fourier analysis algorithm and characterized with amplitude parameters. The fabrication errors of transverse width as well as longitudinal systematic and random etch-depth of the micro-grating device were calculated, respectively. Nanometers order of longitudinal resolution could be achieved with the SWLI, which could realize accurate quantitative characterization of surface topography of micro-grating, subsequently providing with objective reference basis for the assessment of fabrication deviation of binary optical element and the improvement of processing techniques.