METHOD TO MAKE MAGNETIC RAMDOM ACCESSS MEMROY ARRAY WITH SMALL FOOTPRINT
First Claim
1. A method of manufacturing a magnetic random access memory array with small footprint comprising:
- forming a bottom electrode (BE) stack element;
forming a magnetic tunneling junction (MTJ) stack element above the BE;
forming a hard mask (HM) stack element above the MTJ;
forming a photoresist (PR) stack element above the HM;
patterning the MTJ using UV photolithography;
etching the HM stack element using PR stack as mask;
etching the MTJ stack element using the HM stack as mask;
etching the BE stack element using the HM stack as mask; and
refilling the etched area of MTJ and BE with dielectric materials.
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Abstract
This invention is about a method to make magnetic random access memory with small footprint directly on CMOS VIA with a self-aligned etching process. The process schemes of the method proceeds as: (1) Etch MTJ and BE using one or more of RIE and/or IBE processes with Ta as hard mask; (2) Etch BE using one or more of RIE and/or IBE processes with Ta & sidewall protection layer on MTJ as hard mask; and (3) Etch a part of MTJ and BE using one or more of RIE and/or IBE processes with Ta & sidewall protection layer on top portion of MTJ as hard mask. All the three schemes lead the BE to be self-aligned to MTJ cells, the photo overlay margin is not necessary and circuits could be made extremely small with lower manufacturing cost; The invention also provides schemes to prevent the electrical shorting across the tunnel barrier layer. Through trimming and sidewall protection deposition process, device performance and electrical/magnetic properties could be greatly improved.
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Citations
20 Claims
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1. A method of manufacturing a magnetic random access memory array with small footprint comprising:
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forming a bottom electrode (BE) stack element; forming a magnetic tunneling junction (MTJ) stack element above the BE; forming a hard mask (HM) stack element above the MTJ; forming a photoresist (PR) stack element above the HM; patterning the MTJ using UV photolithography; etching the HM stack element using PR stack as mask; etching the MTJ stack element using the HM stack as mask; etching the BE stack element using the HM stack as mask; and refilling the etched area of MTJ and BE with dielectric materials. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification