The electrochemical behaviour during chemical mechanical polishing of Ti in peroxide based alkaline slurries

This work presents an electrochemical investigation of chemical reaction kinetics in CMP of Ti in a peroxide-based alkaline medium. Linear polarization scanning (LP) is combined with electrochemical impedance spectroscopy (EIS) to probe the chemical roles of H2O2 and OH- in CMP. The equivalent circuit is obtained from EIS and each element is given its meaning to chemical kinetics in CMP process. Factors like the thickness of oxide layer, the mass transfer resistance and the capacitance of the double layer can be gamed from the specific values in the equivalent circuit. A gradual oxidizing effect is observed in the chemical reactions, which coincides with the result from X- ray photoelectron spectroscopy (XPS). The results demonstrate how the detailed chemical aspects of the process can be studied by LP and EIS.