In this study, the etching characteristics of ruthenium (Ru) electrode using O-2/Cl-2 helicon plasmas were investigated. The variation of Ru etch rate, Ru to SiO2 etch selectivity and Ru etching slope with varied process variables were scrutinized. Not only the gas chemistry affected the Ru etching, but also the higher bias power and argon (Ar) bombardment helped to faciliate the Ru etching.