In-situ corner rounding during oxide etch for improved plug fill
US5976987A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Oct 3, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A self-aligned contact etch and method for forming a self-aligned contact etch. In one embodiment, the present invention performs an oxide selective etch to form an opening originating at a top surface of a photoresist layer. The opening extends through an underlying oxide layer, and terminates at a top surface of a nitride layer which underlies the oxide layer. Next, the present invention performs a nitride selective etch to extend the opening through the nitride layer to an underlying contact layer. In the present invention, the nitride selective etch causes the photoresist layer to be etched/receded. The nitride selective etch of the present invention further causes the oxide layer to be etched at and near the opening at the interface between the photoresist layer and the oxide layer. As a result, the opening is rounded at the top edge thereof when the layer of photoresist is removed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.