Method of making a three-dimensional memory device using a multi-step hot phosphoric acid wet etch process
US10103169B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 2017 |
| Grant date | Oct 16, 2018 |
| Priority date | — |
| Expiry date | Aug 21, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/037
Abstract
At least one alternating stack of insulating layers and silicon nitride layers is formed over a substrate. Memory stack structures are formed through the at least one alternating stack. A trench and an etch mask spacer are formed such that the trench extends through the entirety of the alternating stack while the etch mask covers upper layers of the at least one alternating stack. Lower silicon nitride layers are removed employing a first hot phosphoric acid wet etch process. After removal of the etch mask spacer, upper silicon nitride layers are removed employing a second hot phosphoric acid wet etch process. Electrically conductive layers are formed in the lateral recesses formed by removal of the silicon nitride layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.