In summary, the process of the present disclosure uses a physical under etch to avoid both chemical damage and physical shorts. Moreover, separate and non-interacting MTJ cells are made using encapsulation material as a self-aligned process, meaning it has no overlay control issue, which is usually associated with sub 60 nm MRAM device fabrication. It is thus possible to replace the widely used chemical RIE etch, which inevitably brings chemical damage on the MTJ sidewall. This process will be used for MRAM chips of the size smaller than 60 nm as problems associated with chemically damaged sidewalls and re-deposition from the MTJ stack and bottom electrode become very severe for the smaller sized MRAM chips.
Although the preferred embodiment of the present disclosure has been illustrated, and that form has been described in detail, it will be readily understood by those skilled in the art that various modifications may be made therein without departing from the spirit of the disclosure or from the scope of the appended claims.