Abstract:
A magnetic thin film deposition is patterned and protected from oxidation during subsequent processes, such as bit line formation, by an oxidation-prevention encapsulation layer of SiN. The SiN layer is then itself protected during the processing by a metal overlayer, preferably of Ta, Al, TiN, TaN or W. A sequence of low pressure plasma etches, using Oxygen, Cl 2 , BCl 3 and C 2 H 4 chemistries provide selectivity of the metal overlayer to various oxide layers and to the photo- resist hard masks used in patterning and metal layer and thereby allow the formation of bit lines while maintaining the integrity of the SiN layer.