High rate dry etching of Ni0.8Fe0.2 and NiFeCo

Abstract

A Cl2/Ar plasma chemistry operated under electron cyclotron resonance (ECR) conditions is found to produce etch rates for NiFe and NiFeCo of ⩾3000 Å min−1 at ⩽80 °C. The etch rates are proportional to ion density and average ion energy over a fairly wide range of conditions. Under the same conditions, fluorine or methane/hydrogen plasma chemistries produce rates lower than the Ar sputter rate. The high ion current under ECR conditions appears to balance NiClx, FeClx, and CoClx etch product formation with efficient ion-assisted desorption, and prevents formation of the usual chlorinated selvedge layer that requires elevated ion etching conditions. Post Cl2-etch removal of surface residues is performed with an in situ H2 plasma exposure.