A reactive ion milling process for patterning narrow track iron nitride recording head poles at the wafer level

A thin metal mask is desirable when defining narrow structures by ion milling. This article explores the definition of narrow high moment iron nitride inductive head pole structures by ion milling in Ar/O₂ and Ar/N₂ gas environments through a Ti mask. Modest ion milling selectivities between Ti and the iron nitrides (FeAlN and FeTaN) were achieved by ion milling in Ar/O₂, although the mill rate of the iron nitrides was reduced dramatically. Selectivities of over 4 were achieved by ion milling in Ar/N₂ ambient, without severely reducing the ion milling rates of the iron nitrides. Hence this reactive mill process is a viable method for defining narrow iron nitride poles by ion milling at the wafer level