Dry etching of iridium films using a TiN mask was studied with a Cl-2/O-2/Ar gas mix in an inductively coupled plasma. The variations in etch rates and etch profiles of iridium films and TiN masks were investigated as a function of O-2 and Cl-2 concentrations. The etch rate of iridium film in this study was in the range 50-100 nm/min. It was found that the ratio of O-2 to Cl-2 concentration in an etch gas strongly influenced the etch selectivity of the iridium film relative to the TiN mask, which in turn impacted the etch profile of iridium films. By increasing coil power and bias voltage, or by decreasing gas pressure, the etch rate and selectivity of iridium films were increased and the etch profile was improved. Iridium etching with a residue-free steep sidewall of 70-80degrees was achieved. (C) 2003 The Electrochemical Society.