Method of refining rare gas halide excimer laser gas
US4740982A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1986 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Sep 22, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/036
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A laser gas used in a rare gas halide excimer laser is efficiently refined with little loss of the essential rare gas such as Kr, Ar or Xe by contact of the laser gas with a solid alkaline compound, e.g. Ca(OH).sub.2, for conversion of acidic impurities and also the halogen source gas such as F.sub.2 or HCl into solid metal halides and contact of the remaining gas with zeolite which is adsorbent of the remaining impurities. When the halogen source gas comprises a highly oxidizing fluorine matter the laser gas is first brought into contact with a reactive metal, e.g. Si or Fe, to convert the oxidizing fluorine matter into metal fluorides to thereby prevent formation of O.sub.2, which is obstructive to the laser operation, by reaction of the oxidizing matter with the alkaline compound. The halogen source gas too can be recovered by initially cooling the laser gas so as to cause condensation of the rare gas and impurities having relatively high boiling points and leave the halogen source gas, which is lower in boiling point, in gas phase.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.