REMOVAL OF CU CONTAMINANTS FROM SI SURFACES USING DRY-CLEANING TECHNIQUES

Removal of Cu contaminants from Si wafer surfaces was tried using remo te hydrogen plasma (RHP) and UV/O-3 cleaning techniques were contamina ted using 1 ppm CuCl2 standard chemical solution the amount of Cu impu rities was monitored by TXRF (total reflection x-ray fluorescence) and XPS (x-ray photoelectron spectroscopy). Our results show that metal I mpurities including Cu can be effectively removed by a hydrogen plasma or UV/O-3 cleaning technique, if only it is performed under optimal p rocess conditions. A two step cleaning process composed of remote H pl asma cleaning, first and UV/O-3 cleaning, next has been found to be mo re effective than a single step process composed of only a remote a pl asma or UV/O-3 cleaning and a two step cleaning process composed of UV /O-3 cleaning, first and remote H plasma cleaning, next. it appeared t hat cleaning efficiency was degraded with increasing the number of rep etition of the cleaning process. The optimal process parameters for th e remote H plasma cleaning are the rf power of 20 W and the exposure t ime of 5 min. The optimal exposure time of the UV/O-3 cleaning for Cu impurity removal is 1 min. Cleaning efficiency is degraded with increa sing the process parameters above the optimal values for both RHP and UV/O-3 cleaning techniques.