Abstract: We describe a new method for etching patterns in silver, copper, or gold, or other plate metal thin films. A pattern of a hard mask is placed onto the surface of the thin film, followed by a step of reactive ion etching using a plasma formed using a gas feed of some combination of some amounts of methane (CH4) and hydrogen (H2), and some or no amount of Argon (Ar). The areas of silver, copper or gold not covered by the hard mask are etched while the hard mask protects those areas that will form the raised portions of thin film in the final structure.