Patent ID: 8105850

Claim:
A process for selectively patterning a magnetic film structure, comprising: providing a magnetic structure comprising at least one bottom magnetic layer, at least one top magnetic layer, wherein the at least one bottom magnetic layer is separated from the at least one top magnetic layer by a tunnel barrier layer, wherein the at least one top magnetic layer and the at least one bottom magnetic layer are the same or are different and are selected from the group consisting of Ni x CO y Fe z and CO x Fe y B z , wherein x, y, and z are integers whose sum adds up to 100, and said at least one top magnetic film layer having a protective layer located thereon; forming a patterned resist on said protective layer, wherein a portion of said protective layer is exposed; selectively etching said exposed portion of said protective layer by a reactive-ion etching process to expose portion of said at least one top magnetic film layer; and selectively etching said exposed portion of said at least one top magnetic film layer by a wet process which includes an etchant solution comprising at least one acid, and an organophosphorus acid inhibitor or salt thereof, stopping on said tunnel barrier layer, wherein the organophosphorus acid inhibitor or salt thereof is an alkylphosphoric acid of the formula: CH 3 (CH 2 ) n OPO(OH) 2 , wherein n is 5 to 11.