Combined physical and chemical etch to reduce magnetic tunnel junction (MTJ) sidewall damage
US10522749B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 2017 |
| Grant date | Dec 31, 2019 |
| Priority date | — |
| Expiry date | May 15, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/3065
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A process flow for forming magnetic tunnel junction (MTJ) nanopillars with minimal sidewall residue and minimal sidewall damage is disclosed wherein a pattern is first formed in a hard mask that is an uppermost MTJ layer. Thereafter, the hard mask sidewall is etch transferred through the remaining MTJ layers including a reference layer, free layer, and tunnel barrier between the free layer and reference layer. The etch transfer may be completed in a single RIE step that features a physical component involving inert gas ions or plasma, and a chemical component comprised of ions or plasma generated from one or more of methanol, ethanol, ammonia, and CO. In other embodiments, a chemical treatment with one of the aforementioned chemicals, and a volatilization at 50° C. to 450° C. may follow an etch transfer through the MTJ stack with an ion beam etch or plasma etch involving inert gas ions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.