Effect of inert gas additive on Cl2-based inductively coupled plasma etching of NiFe and NiFeCo

NiFe and NiFeCo thin films have been etched in Cl-2/He, Cl-2/Ar and Cl-2/Xe inductively coupled plasmas as a function of pressure, source power, and rf chuck power. The etch rates decrease, with increasing pressure, and go through a maximum with both source and chuck power. The results are consistent with a mechanism involving ion-assisted desorption of relatively involatile etch products, and a balance of ion flux, ion energy, and chlorine neutral density is necessary to achieve practical etch rates and smooth surfaces. Under our conditions, Cl-2/He provided the best surface morphologies and the least residual chlorine. (C) 1999 American Vacuum Society. [S0734-2101(99)00104-9].