US Patent 10566526 Patterning of a magnetoresistance structure including two hard masks

A method includes depositing on a substrate a magnetoresistance stack, depositing a first hard mask on the magnetoresistance stack, depositing a first photoresist on the first hard mask, patterning the first photoresist to expose portions of the first hard mask, and etching the exposed portions of the first hard mask to expose a portion of the magnetoresistance stack. The method further includes stripping the first photoresist, etching the exposed portions of the magnetoresistance stack and the first hard mask to form a first intermediate structure having a base and a pillar structure, depositing an etch barrier on the first intermediate structure, and depositing a second hard mask on the etch barrier. A second photoresist is deposited on the second hard mask. The method further includes patterning the second photoresist to expose portions of the second hard mask, etching the exposed portions of the second hard mask, stripping the second photoresist, etching a portion of the second hard mask, a portion of the etch barrier and the base to form a second intermediate structure, and depositing a capping barrier on the second intermediate structure.