Surface chemistry studies of copper chemical mechanical planarization

Surface chemistry studies of the chemical mechanical planarization (CMP) of copper are presented in this paper. Blanket copper samples were polished w ith an acidic alumina-based slurry which contains an organic acid salt (pht halic acid salt) and an oxidizer (H2O2). Surface studies using X-ray photoe lectron spectroscopy (XPS) were performed on copper samples after chemical etching or CMP in order to determine the effect that different polishing pa rameters (i.e., pH and oxidizer concentration) have on the copper surface. XPS studies were also done on samples that were passively soaked in an acid ic slurry mixture containing different concentrations of H2O2 to determine how the chemical action alone affects the removal of copper. The etching re sults revealed that a cuprous oxide (Cu2O) forms on the surface of etched m etal while polished samples showed CuO and Cu(OH)(2). The effect of these c opper oxide films on the removal of copper in passive etching and chemical mechanical polishing is discussed. (C) 2001 The Electrochemical Society.