The dry etching characteristics of Mo and IGZO were investigated for the less mask process development, because the selectivity of Mo and IGZO is the most important factor in the fabrication of the 2nd S/D etching process. IGZO thin films were deposited with an RF magnetron sputtering system, and Mo thin films were deposited with a DC magnetron sputtering system. The etch rates of Mo and IGZO films was investigated with varying RF power (13.56 MHz, 2 MHz), pressure and partial pressure of Cl(2) using a dual frequency CCP-RIE system. With increasing low frequency power, pressure and partial pressure of Cl(2), the etch rate of Mo increased. However, the etch rate of IGZO decreased slightly or showed little change under the same process condition. The highest selectivity of Mo and IGZO was 16.76, while the etch rate of Mo was 391 nm/min, and that of IGZO was 23 nm/min. (C) 2011 Elsevier B.V. All rights reserved.