  Accurate modeling of light scattering from nanometer scale defects on Silicon
wafers is critical for enabling increasingly shrinking semiconductor technology
nodes of the future. Yet, such modeling of defect scattering remains unsolved
since existing modeling techniques fail to account for complex defect and wafer
geometries. Here, we present results of laser beam scattering from spherical
and ellipsoidal particles located on the surface of a silicon wafer. A
commercially available electromagnetic field solver (HFSS) was deployed on a
multiprocessor cluster to obtain results with previously unknown accuracy down
to light scattering intensity of -170 dB. We compute three dimensional
scattering patterns of silicon nanospheres located on a semiconductor wafer for
both perpendicular and parallel polarization and show the effect of sphere size
on scattering. We further computer scattering patterns of nanometer scale
ellipsoidal particles having different orientation angles and unveil the
effects of ellipsoidal orientation on scattering.
