The process module development and device characteristics of dual metal gate complementary metal-oxide-semiconductor (CMOS) with TaSiN and Ru gate electrodes on HfO2 dielectric are reported. Highly selective wet etch processes for various metal gate materials (TaSiN, TiN, and TaN) have been developed with a minimal impact on HfO2 and HfSiON. A plasma etch process is developed to etch TaSiN and Ru dual metal gate stacks simultaneously on the same wafer. Well behaved dual metal gate CMOS transistors with gate length down to 85 nm have been demonstrated. This integration method is highly versatile and can be applied to various metal gate materials. (c) 2005 The Electrochemical Society.