Highly selective reactive-ion etching for NiFe with Ti mask by inductively coupled plasma

Abstract We have succeeded in accomplishing the highly selective etching of NiFe against Ti masks by an inductively coupled plasma-reactive ion etching technique. This technique utilized CHF3/CH4/O2/NH3. The etching selectivity of Ti against NiFe was remarkably varied from 9.7 to ∼0 by changing CHF3/O2/NH3 to CH4/O2/NH3 gas. According to the X-ray photoelectron spectroscopy results of the sample after the etching in CH4/O2/NH3 discharge, it was found that TiO2 was synthesized at the surface of Ti. The existence of TiO2 is considered to lead the high-etching selectivity.