<title>Determination of COP distribution after SC1 cleaning by a laser particle counter</title>

Abstract

COPS (crystal originated particle/pit), which are considered to be originated from grown-in defects formed during CZ crystal growth and degrade GOI (gate oxide integrity) of MOS ULSI devices, were studied with respect to the size and density distribution on a surface of CZ grown Si wafer by means of laser particle counter. Firstly we studied the relation between detection limit of COP size and various measurement parameters such as PMT (photomultiplier) gain and threshold level of laser particle counter (SFS6200) using AFM (atomic force microscope), OPP (optical precipitate profiler), and LST (infrared light scattering tomography). Then this method was applied to evaluation of as grown CZ Si wafer containing Ring-OSF region, which were revealed after annealing such as 1000 degrees Celsius for 1 hour in dry O2, and the COP size and density distribution were compared to those of the grown-in defects measured by OPP and LST. It was found COP measured by laser particle counter had good correlation in the size and density distribution with the grown-in defects measured by OPP and LST, and the COP showed slightly higher density than the grown-in defects by OPP. This means COP measurement by laser particle counter is a more sensitive method to evaluate grown-in defects than OPP and LST.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.