Electrochemical characterization of copper chemical mechanical polishing

Chemical mechanical polishing (CMP) of copper was performed using H2O2, as oxidizer and alumina particles as abrasives. The interaction between the Cu surface and the slurry was investigated by potentiodynamic measurements taken during the polishing process as well as under static conditions. The Cu removal rate reached a maximum at 1% H2O2 concentration, and decreased with a further increase in H2O2 concentration. The static etch rate showed the same trend. Atomic force microscopic measurements were performed on both the etched surface and polished surface. It was shown that the surface roughness of the polished surface increased as the H2O2 concentration increased. This can be explained by changes in the structure of the passivating layer and the dominating role of the dynamic repassivation during polishing. (C) 2003 Elsevier B.V. All rights reserved.