Optical Scattering From Surfaces

We study how material properties, surface topography, and contaminants affect the distribution of light scattered from surfaces, with an aim toward

Developing standard measurement methods and standard artifacts for use in industry, and

Providing a basis for interpreting scattered light distributions so that industry can optimize their use of optical scatter methods.

Applications include evaluation of highly polished optical surfaces, bulk optical materials, surface residues, and diffuse scattering materials. Optical scattering is also used to assess uniformity of periodic structures such as found on compact disks, patterned photoresists, and deposited lines on semiconductors. Experiments are underway to correlate the optical scatter from silicon wafers with properties such as surface microroughness, particulate contamination, and subsurface defects in order to facilitate optical scattering measurements in assembly line applications. Different sources of scattered light are expected to have unique signatures in the scattered light distribution.