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, Cl2/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, Cl2/He provided the best surface morphologies and the least residual chlorine.