Inductively coupled plasma reactive ion etching of titanium nitride thin films in a Cl2/Ar plasma

An inductively coupled plasma reactive ion etching of TiN thin films was carried out using a Cl2/Ar gas chemistry. The etch characteristics such as the etch rate and etch profile were investigated by varying gas concentration and etch parameters including coil radio frequency (rf) power, dc-bias voltage and gas pressure. As the Cl2 concentration increased, the etch rates of TiN thin films increased while the sidewall slopes of the etched films became slanted without the redeposition or etch residues. With increasing coil rf power and dc-bias voltage, the etch rates increased and etch slope became steep. Gas pressure has a little effect on etch rate and better etch profile was obtained at low gas pressure. Finally, highly anisotropic etching of TiN thin a film using a photoresist mask was achieved at the optimized etch condition.