Trench sidewall patterned by vapor phase etching
US5838055A · kind A · utility
110Cited by
19References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 29, 1997 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | May 29, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31144
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Hydrogen fluoride undercut of oxide layers may be reduced by using a low pressure mixture of gaseous hydrogen fluoride and gaseous ammonia mixture. Organic photoresists can be used as a masking material when using the gaseous hydrogen fluoride/ammonia mixture without resulting in an enhanced reaction rate. In addition, because of the reaction conditions, the dimensions in the oxide layer being etched can be specifically sized smaller than openings made in the overcoating masking material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.