A high selectivity patterning technology of vanadium oxide (VOx) thin film was suggested in this paper. VOxthin film was etched through a photoresist (PR) mask using Cl/N based gases in a reactive ion etching (RIE) system. Taguchi method was used for process design to identify factors that influence the patterning and find optimum process parameters. Experimental results suggested that RF power was the largest contribution factor for VOxetch rate, PR selectivity and uniformity on 6 inch diameter wafer. Uniformity and PR selectivity were improved by introducing a small amount of N2. High resolution and low roughness patterning transfer was achieved with a non uniformity of 2.4 %, an VOxetch rate of 74 nm/min, a PR selectivity of 0.96, a Si3N4selectivity of 5 and a SiO2selectivity of 10.