A simple and rapid method is proposed for nanoscale patterning on a metallic glass surface using focused ion beam irradiation followed by wet etching. It was found that the etch rate of a metallic glass surface irradiated with Ga+ ions could be drastically changed, and rapid patterning was possible with this method. Cross-sectional transmission electron microscopy observation reveals that the metallic glass substrate maintains an amorphous phase following irradiation. Etching enhancement was not observed for irradiation with Ar+ ions. The results indicate that enhancement of etching results from the presence of implanted Ga+ ions rather than a change in crystallography. (c) 2006 American Institute of Physics.