Plasma enhanced chemical vapor deposition of films for improved vertical etch performance in 3D NAND memory devices
US11365476B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2019 |
| Grant date | Jun 21, 2022 |
| Priority date | — |
| Expiry date | Jul 21, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10B43/27
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present disclosure generally relate to thin films incorporating high aspect ratio feature definitions and methods for forming the same. As gate height increases, 3D NAND gate stacks are subject to higher aspect ratio etching. Due to the current limitations of etching techniques, the vertical etch profile typically tapers as the depth into the gate stack increases. The inventors have devised a unique deposition scheme that compensates for etch performance degradation in deep trenches by a novel plasma-enhanced chemical vapor deposition (PECVD) film deposition method. The inventors have found that by grading various properties (e.g., refractive index, stress of the film, dopant concentration in the film) of the as-deposited films (e.g., silicon nitride) a more uniform etch profile can be achieved by compensating for variations in both dry and wet etch rates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.