Process for purifying nitrogen trifluoride gas
US4980144A · kind A · utility
9Cited by
2References
10Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 24, 1989 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | May 24, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02C20/30
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
This invention relates to a process for obtaining a high purity nitrogen trifluoride gas which is used as a dry etching agent for semiconductors or a cleaning gas for CVD apparatus, etc., particularly to a process for removing oxygen difluoride. This is a process for purifying a nitrogen trifluoride gas by, after removing hydrogen fluoride from a nitrogen trifluoride crude gas, contacting with at least one aqueous solution containing one selected from the group consisting of sodium thiosulfate, hydrogen iodide and sodium sulfide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.