An improved method of etching a metal substrate is described. After a mask layer is applied to the metal substrate, an ion implantation process is performed which implants ions, such as oxygen ions, into the exposed regions of the metal substrate. This implantation creates regions of metal oxide, which may be more susceptible to etching. Afterwards, the exposed regions of metal oxide are subjected to an etching process. This process may be through vaporization or may be a wet etch process. In some embodiments, the etchant is selected so that the metal oxide binds with the etchant to form a volatile compound, which stays in the vapor or gaseous state. This may reduce the unwanted deposition of the metal to other surfaces. These ion implantation and etching processes may be repeated a plurality of times to create a recessed feature of the desired depth.