Optical measurement of COP defects on silicon wafer surface by laser scattered defect pattern

This paper presents new optical measurement method for evaluating the defects on a silicon wafer surface quantitatively by detecting the intensity distribution, " laser scattered defect pattern ( LSDP )(1))", corresponding to the superposition of scattered light from a defect and reflected light from a surface. In order to verify a feasibility to detect "crystal originated particles ( COPs )(2))" and to discriminate them from particulate contaminations, the basic experiments were carried out for the silicon wafer surface with COPs identified by making the use of Atomic Force Microscope (AFM). Then, it was found that COPs with the size of sub-micro meter scale were able to be detected as LSDPs and suggested that our proposed method had a feasibility of discrimination between COPs and particulate contaminations by measuring the contrast of LSDP.