Utility of dodecyl sulfate surfactants as dissolution inhibitors in chemical mechanical planarization of copper

Y. Hong

Interdisciplinary Engineering Science, Clarkson University, Potsdam, New York 13699-5665

U.B. Patri, and S. Ramakrishnan

Department of Chemical Engineering, Clarkson University, Potsdam, New York 13699-6650

D. Roy

Department of Physics, Clarkson University, Potsdam, New York 13699-5820

S.V. Babu

Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5665

An important component of the slurries used in chemical mechanical planarization (CMP) is an appropriately chosen corrosion/dissolution inhibitor, which facilitates selective material removal from protrusions while protecting recessed regions of the surface. The present work demonstrates the utility of two environmentally benign anionic surfactants, sodium dodecyl sulfate (SDS) and ammonium dodecyl sulfate (ADS) as dissolution inhibitors. Using a standard slurry (1 wt% glycine with 5 wt% H₂O₂ at pH = 4.0) typically used for Cu CMP and combining measurements of open circuit potentials and contact angles with those of Cu removal rates, we show that both SDS and ADS suppress chemical dissolution and polish rates of Cu. The dissolution inhibition efficiencies of ADS and SDS measured in these experiments are found to be superior to those of benzotriazole (BTA), a traditional inhibiting agent used for copper CMP.