Methods for forming a self-aligned contact via selective lateral etch
US9368369B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 2014 |
| Grant date | Jun 14, 2016 |
| Priority date | — |
| Expiry date | Dec 19, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76897
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In some embodiments methods of processing a substrate include: providing a substrate having a contact structure formed on the substrate, wherein the contact structure comprises a feature defined by gate structures, a silicon nitride layer disposed on a upper surface of the gate structures and on sidewalls and a bottom of the feature, and an oxide layer disposed over the silicon nitride layer and filling the feature; etching an opening through the oxide layer to the silicon nitride layer disposed on the bottom of the opening, wherein a width of the opening is less than a width of the feature; expanding the opening in the oxide layer to form a tapered profile; exposing the substrate to ammonia and nitrogen trifluoride to form an ammonium fluoride gas that forms an ammonium hexafluorosilicate film on the oxide layer; and heating the substrate to a second temperature to sublimate the ammonium hexafluorosilicate film.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.