In this paper, the effect of impurity distribution in copper film on corrosion in chemical mechanical planarization process was studied. The corrosion behavior was investigated by electrochemical and surface analytical techniques. An energy dispersive X-ray analyses attached to a focus ion beam was used to analyze the distribution of impurities. As more impurities were accumulated at the grain boundary, the copper oxide film formed in the slurry tended to be porous. Therefore, corrosion was enhanced. The correlation between corrosion behavior and distribution of impurity was established herein. (c) 2007 The Electrochemical Study.