Defect inspection of wafers by laser scattering

This paper reviews defect inspection methods and instruments for evaluating semiconductor wafers by using elastic light scattering. The discussion focuses on the following instrument characteristics: minimum detectable size for the adhering particle, inspection throughput, detectability of microroughness and detectability of crystal defects at the subsurface and in the volume. By analyzing the detection mechanisms of laser surface scanners, scatterometers and infrared tomography systems, the unique capabilities of elastic light scattering for defect detection are revealed.