Electrochemical characteristic of chemical-mechanical polishing of copper with oxide passive film

Electrochemical behavior of chemical-mechanical polishing of copper with oxide passive film was studied by electrochemical measurement technologies. Dependences of polarization curves and electrochemical parameters, the rate of formation or removal of passive film of copper on film modifier KClO3 were investigated. The rules of dependences of corrosion potentials and corrosion current densities on polishing pressure and rotation rate were obtained. It is discovered that the rates of formation and removal of passive film of copper are enhanced, while the polishing pressure and rotation rate are reduced. The experiments show that the CMP processes decrease Tafel slope, increase electron transfer coefficient of anode reaction and decrease the activation energy of corrosion reaction of copper, thereby the corrosion processes are accelerated. The results indicate that CMP slurry recipe, which is composed of NaAc-NaOH medium, using KClO3 as passive film modifier and nano-sized γ-Al2O3 as abrasive, is feasible and reasonable. The technological conditions are 100 r/min, 16 kPa.