Polarized Optical Scattering Measurements of Nanoparticles Upon a Thin Film Silicon Wafer

The diameter and distribution measurements of nanoparticles on wafers are critical parameters in the semiconductor industry to ensure the quality of the transistors and increase the production rate. A goniometric optical scatter instrument has been developed at CMS / ITRI to readily perform polarized light scattering measurements for the diameter and distribution measurements of nanoparticles on wafers. The designed scatter instrument is capable of distinguishing various types of optical scattering characteristics, which are corresponding to the diameters of the nanoparticles, near surfaces by using the Mueller matrix calculation. The measurement range of nanoparticle diameters is 50 nm to 350 nm on 4 inches to 8 inches thin film wafers. These results demonstrate that the polarization of light scattered by particles can be used to determine the size of particulate contaminants on silicon wafers.