Interhalogen plasma chemistries for dry etch patterning of Ni, Fe, NiFe and NiFeCo thin films

ICl/Ar and IBr/Ar plasmas operated in an inductively coupled plasma (ICP) source have been examined for dry etching of Ni, Fe, NiFe and NiFeCo. The removal of the Fe etch products limits the etch rates under most conditions, but rates of ~500 Å min -1 are obtained for both NiFe and NiFeCo in both chemistries. The etched surfaces are smooth (atomic force microscopy root-mean-square roughness <1 nm) over a broad range of plasma conditions, with small residual halogen concentrations (≤2 at.%).