We investigated the usefulness of NbOx nanopillars as an etching mask of dry etching for the formation of Si nanodot arrays. The NbOx nanopillar arrays were prepared by the anodic aluminum oxidation process of Al and Nb thin films. The etch rate and etch profile of NbOx nanopillar arrays were examined by varying the experimental conditions such as the concentration of etch gas, coil rf power, and dc bias voltage in the reactive ion etch system using the inductively coupled plasma. As the concentration of Cl2 gas increased, the etch rate of NbOx nanopillars decreased. With increasing coil rf power and dc bias voltage, the etch rates were found to increase. The etch characteristics and etch mechanism of NbOx nanopillars were investigated by varying the etch time under the selected etch conditions.