Fabrication of large height top metal electrode for sub-60nm magnetoresistive random access memory (MRAM) devices
US11088320B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 11, 2019 |
| Grant date | Aug 10, 2021 |
| Priority date | — |
| Expiry date | Feb 6, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N50/85
- WIPO fieldMicro-structural and nano-technology
- WIPO sectorChemistry
Abstract
A process flow for forming magnetic tunnel junction (MTJ) cells with a critical dimension CD≤60 nm by using a top electrode (TE) hard mask having a thickness≥100 nm prior to MTJ etching is disclosed. A carbon hard mask (HM), silicon HM, and photoresist are sequentially formed on a MTJ stack of layers. A pattern of openings in the photoresist is transferred through the Si HM with a first reactive ion etch (RIE), and through the carbon HM with a second RIE. After TE material is deposited to fill the openings, a chemical mechanical process is performed to remove all layers above the carbon HM. The carbon HM is stripped and the resulting TE pillars are trimmed to a CD≤60 nm while maintaining a thickness proximate to 100 nm. Thereafter, an etch process forms MTJ cells while TE thickness is maintained at ≥70 nm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.