Method of Etching MTJ Using CO Process Chemistries

摘要

A method for fabricating a magnetic film structure is provided. The method comprises forming a magnetic structure on a bottom electrode layer, the magnetic structure comprising at least one pinned bottom magnetic film layer having a fixed magnetic orientation; at least one top magnetic film layer whose magnetic orientation can be manipulated by a current; and a tunneling layer between the bottom magnetic film layer and the top magnetic film layer; forming a metallic hard mask atop the magnetic structure; patterning and etching the metallic hard mask to define exposed areas of the magnetic structure; selectively etching the exposed areas of the magnetic structure by a chemical etch process based on a CO etch chemistry to form discrete magnetic bits.

主权项

1. A method for fabricating a magnetic film structure, wherein the method comprises:
forming a magnetic structure on a bottom electrode layer, the magnetic structure including:
at least one pinned bottom magnetic film layer having a fixed magnetic orientation;at least one top magnetic film layer having a magnetic orientation that can be manipulated by a current; anda tunneling layer between the at least one pinned bottom magnetic film layer and the at least one top magnetic film layer; forming a metallic hard mask above the magnetic structure; etching, by inductively-coupled plasma etching, the metallic hard mask, but not the magnetic structure, using a first chemistry; starting etching of the magnetic structure using a second chemistry to form at least one magnetic bit; monitoring a signal of a spectral signature of a plasma at a predetermined wavelength while etching the magnetic structure; stopping etching the magnetic structure when a drop in the signal is observed; and over-etching, by inductively-coupled plasma etching, at least one sidewall of the at least one magnetic bit, wherein the second chemistry is different from the first chemistry.