An automated surface inspection system, KLA-Tencor SP1-TBI, was used to investigate the surface defectivity of three different sets of bare silicon wafers, in order to test the capability of the tool to distinguish between particles (removable defects) and pits, generally called COPs (Crystal Originated Particles). Two different type of MEMC products have been investigated: The Advanta wafers characterized by a low density of COPs and with an annular region at the edge of the wafer that is “free” of any agglomerated defect; A standard P100 polished material in which the COP defects are
present on a large portion of the wafer surface almost with the same density. When the SP1-TBI discrimination algorithm is applied, real time defect classification (RTDC) is performed and the resulting wafer map displays simultaneously but differently particles and COPs due to their different scattering behavior. The validation of the SP1-TBI scan results has been performed in two ways. The first one making a pre to post cleaning comparison and the second one by Optical and Atomic Force Microscope investigation. In both cases the confidence level of the algorithm is depending on the material investigated but is generally greater then 90% allowing considering the SP1-TBI algorithm as a good system to distinguish particles from COPs.