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 Cl2/He, Cl 2/Ar and Cl2/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, Cl2ZHe provided the best surface morphologies and the least residual chlorine. © 1999 American Vacuum Society.