Patent ID: 10153427

Abstract:
A process flow for forming magnetic tunnel junctions (MTJs) with minimal sidewall residue and reduced low tail population is disclosed wherein a pattern is first formed in a hard mask that is an uppermost MTJ layer. Thereafter, the hard mask pattern is etch transferred through the underlying MTJ layers including a reference layer/tunnel barrier/free layer stack. The etch transfer may be completed in a single RIE step based on a first flow rate of O2 and a second flow rate of an oxidant such as CH3OH where the CH3OH/O2 ratio is at least 7.5:1. The RIE may also include a flow rate of a noble gas. In other embodiments, a chemical treatment with an oxidant such as CH3OH, and a volatilization at 50° C. to 450° C. may follow an etch transfer through the MTJ stack when the ion beam etch or plasma etch involves noble gas ions.