Removal of native oxide with high selectivity
US9034773B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 12, 2013 |
| Grant date | May 19, 2015 |
| Priority date | — |
| Expiry date | Jun 12, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32357
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Provided are methods and systems for removing a native silicon oxide layer on a wafer. In a non-sequential approach, a wafer is provided with a native silicon oxide layer on a polysilicon layer. An etchant including a hydrogen-based species and a fluorine-based species is introduced, exposed to a plasma, and flowed onto the wafer at a relatively low temperature. The wafer is then heated to a slightly elevated temperature to substantially remove the native oxide layer. In a sequential approach, a wafer is provided with a native silicon oxide layer. A first etchant including a hydrogen-based species and a fluorine-based species is flowed onto the wafer. Then the wafer is heated to a slightly elevated temperature, a second etchant is flowed towards the wafer, and the second etchant is exposed to a plasma to complete the removal of the native silicon oxide layer and to initiate removal of another layer such as a polysilicon layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.