Process for in-situ etching a hardmask stack
US6696365B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 7, 2002 |
| Grant date | Feb 24, 2004 |
| Priority date | — |
| Expiry date | Aug 4, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/0276
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of etching high aspect ratio, anisotropic deep trench openings in a silicon substrate coated with a multilayer mask comprising in sequence a pad oxide layer, a silicon nitride layer, a doped or undoped silicon oxide hard mask layer, a polysilicon hard mask layer, an antireflection coating and a patterned photoresist layer in a single chamber comprising patterning the antireflection coating and hard mask layer, removing the photoresist and antireflection layers with oxygen, using the patterned polysilicon as a hard mask layer etching an opening in the silicon oxide hard mask layer, the silicon nitride layer and the pad oxide layer, removing the polysilicon hard mask layer with CF4/CHF3, and etching an anisotropic deep trench in the silicon substrate using the patterned silicon oxide hard mask layer as a mask and an etchant mixture including nitrogen trifluoride that self-cleans the chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.