Method and apparatus for etching a metal layer disposed on a substrate, such as a photomask, are provided. In one aspect, a method is provided for processing a substrate including positioning the substrate in a processing chamber, introducing a processing gas comprising (i) hydrogen chloride, (ii) an oxygen containing gas, (iii) another chlorine containing gas, and optionally, (iv) an inert gas into the processing chamber, wherein the substrate is maintained at a reduced temperature, and the processing gas is excited into a plasma state at a reduced power level to etch exposed portions of the metal layer disposed on the substrate.