Removal of Cu contaminants from Si surfaces using dry cleaning techniques

초록

Removal of Cu contaminants from Si wafer surfaces was tried using remote hydrogen plasma (RHP) and UV/O3 cleaning techniques were contaminated using 1ppm CuCl2 standard chemical solution the amount of Cu impurities was monitored by TXRF (total reflection x-ray fluorescence) and XPS (x-ray photoelectron spectroscopy). Our results show that metal impurities including Cu can be effectively removed by a hydrogen plasma or UV/O3 cleaning technique, if only it is performed under optimal process conditions. A two step cleaning process composed of remote H plasma cleaning, first and UV/O3 cleaning, next has been found to be more effective than a single step process composed of only a remote H plasma or UV/O3 cleaning and a two step cleaning process composed of UV/O3 cleaning, first and remote H plasma cleaning, next. It appeared that cleaning efficiency was degraded with increasing the number of repetition of the cleaning process. The optimal process parameters for the remote H plasma cleaning are the rf power of 20W and the exposure time of 5min. The optimal exposure time of the UV/O3 cleaning for Cu impurity removal is 1min. Cleaning efficiency is degraded with increasing the process parameters above the optimal values for both RHP and UV/O3 cleaning techniques.