CL-2-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, an d CrSi in Cl-2/Ar, Cl2N2, and Cl-2/H-2 chemistries is reported. The et ch rates are a strong function of discharge composition, with maxima a t 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 f ormation 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 t hick chlorinated selvedge layer on NiFe and NiFeCo.