Highly Physical Etch Resistive Photoresist Mask to Define Large Height Sub 30nm Via and Metal Hard Mask for MRAM Devices

A method for fabricating a magnetic tunneling junction (MTJ) structure comprising:

• depositing a conductive via layer on a bottom electrode;
• patterning said conductive via layer and then trimming said conductive layer to form a sub 20 nm conductive via having a height 50 nm on said bottom electrode;
• encapsulating said conductive via with a first dielectric layer and planarizing said first dielectric layer to expose a top surface of said conductive via;
• thereafter depositing a MTJ stack on encapsulated said conductive via wherein said MTJ stack comprises at least a pinned layer, a barrier layer on said pinned layer, and a free layer on said barrier layer;
• depositing a top electrode layer on said MTJ stack;
• patterning said top electrode layer and then trimming said top electrode layer to form a sub 30 nm hard mask;
• and
• thereafter etching said MTJ stack using said hard mask to form an MTJ device and over etching said MTJ stack into said encapsulation layer but not into said bottom electrode wherein metal re-deposition material is formed on sidewalls of said encapsulation layer underlying said MTJ device and not on sidewalls of a barrier layer of said MTJ device.

A magnetic tunneling junction (MTJ) comprising:

• a sub-30 nm MTJ device on a sub-20 nm conductive via encapsulated by a dielectric layer;
• a bottom electrode underlying said conductive via;
• and
• a top electrode overlying and contacting said MTJ device.