METHOD OF ENGRAVING A METAL LAYER BY IONIC ATTACK

Abstract

Abstract Ion etching a metal layer, esp. a layer of non-oxidisable metal, e.g. according to a pattern of narrow metallic strips on a semiconductor substrate, with strips and gaps of width e.g. about 1 mu, comprises (a) depositing on the metal layer to be etched a metal masking layer of a metal more resistant to ion etching: (b) forming a layer of protective lacquer according to the described pattern of metallisation on the metal protective layer; (c) chemically etching the protective metal layer in the regions not to be metallised, using an etchant only effective on the two protective layers; (d) forming a plasma in the neighbourhood of the layers and ion etching the main metal layer in the regions not to be metallised, using the plasma. The plasma contains >0.1 vol.% O2 and the protective metal layer is an oxidisable metal. The process avoids the necessity for the metallic protective layer to be as thick as the metal layer to be etched when the latter is thick (e.g. is approx. 2 mu) since the O2 present oxides the metal protective layer to form a more ion resistant protective coating.

Inventors

• 👤 Jean-Pierre Andrieu
• 👤 Jean-Pierre Pestie

Bibliographic Details