Methods for etching a metal layer to form an interconnection structure for semiconductor applications

A method of patterning a metal layer on a substrate, comprising:

• (a) performing an etching process comprising an etching gas mixture consisting essentially of a hydro-carbon gas on a metal layer disposed on a substrate in a processing chamber and removing between about 10 percent and about 30 percent of a thickness of the metal layer from the substrate;
• (b) subsequently switching the etching process to perform an ashing process comprising an ashing gas mixture consisting essentially of a hydrogen gas and an inert gas on the metal layer for etching byproducts removal;
• and
• (c) repeatedly performing steps (a) and (b) until desired features are formed in the metal layer.

A method of patterning a metal layer on a substrate, comprising:

• supplying an etching gas mixture consisting essentially of methane (CH4) to a processing chamber having a substrate disposed therein, the substrate having a metal layer disposed thereon;
• etching a portion of the metal layer from the substrate, wherein the portion of the metal layer is about 10 percent and about 30 percent of a thickness of the metal layer from the substrate;
• subsequently switching the etching gas mixture to an ashing gas mixture consisting essentially of a hydrogen gas, the ashing gas mixture exposed to the metal layer exposed on the substrate for etching byproducts removal;
• and
• cyclically supplying the etching gas mixture and the ashing gas mixture to the processing chamber for at least three times until desired features are formed in the metal layer.