METHODS AND APPARATUS FOR CHARACTERIZING A SURFACE

摘要

A system (10) and method for characterizing a surface are disclosed. The system (10) includes a light source (14) and source optics (18) which direct a beam of light (16) toward the surface (12). A first optical integrating device (30) is positioned and configured to receive a first portion of the scattered light (24) which corresponds to a first range of spatial frequencies. A second optical integrating device (40) is positioned and configured to receive a second portion of the scattered light corresponding to a second range of spatial frequencies. In one embodiment, an intergrating sphere is employed as the first optical integrating device. The sphere includes a sampling aperture (34) which is surrounded by a light absorption region (62) on the interior of the sphere. Total integrated scatter data is generated for each range of spatial frequencies and is used to approximate the spectral scatter function of the surface. RMS roughness is then approximated for any range of spatial frequencies.