Cl2-based inductively coupled plasma etching of NiFe and related materials

A parametric study of etch rates, surface quality, and mask: materials for inductively coupled plasma (ICP) dry etched NiFe, NiFeCo, TaN, and CrSi in Cl-2/Ar, Cl2N2, and Cl-2/H-2 chemistries is reported. The etch rates are a strong function of discharge composition, with maxima at similar to 66% Cl-2 in each of the chemistries investigated, as are ion flux, ion energy, and pressure. The etch mechanism appears to be formation of chlorides that are desorbed by ion assistance. If the ion-to-neutral ratio is not optimized, then the etching reverts either to a pure sputtering regime or to net deposition through formation of a thick chlorinated selvedge layer on NiFe and NiFeCo.