Purifying agent and purification method for halogen-containing exhaust gas
US6325841A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 2000 |
| Grant date | Dec 4, 2001 |
| Priority date | — |
| Expiry date | May 16, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S95/901
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A cleaning agent and a cleaning process for efficiently removing noxious halogen-based gases such as fluorine, chlorine, boron trifluoride, boron trichloride and tungsten hexafluoride from exhaust gases from semiconductor fabrication processes. The cleaning agent is produced by adherently adding alkali metal formate and/or alkaline earth metal formate to activated carbon, or adherently adding alkali metal hydroxide and/or alkaline earth metal hydroxide together with alkali metal formate and/or alkaline earth metal formate to activated carbon. By exposing exhaust gases to the cleaning agent, noxious halogen-based gases in the exhaust gases are efficiently removed with little desorption of halogen-based gases adsorbed on the cleaning agent. Also, the cleaning treatment is further improved in safety and efficiency by a pre-treatment cleaning agent comprising a metal oxide or a metal hydroxide and a post-treatment cleaning agent prepared by adherently adding sodium formate to a metal oxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.