A metallic thin film of copper, silver, gold, or one alloy selected from alloys containing as a main component at least one of these metals is etched by plasma of an etching gas containing at least nitrogen oxide while being reacted with the plasma, whereby making it possible to fine-process electrically...http://www.google.fr/patents/US6878635?utm_source=gb-gplus-shareBrevet US6878635 - Dry etching
