| 摘要 |
PURPOSE:To remove impurities efficiently and perform stable, continuous operation for a long period by causing a laser gas that contains a fluoric gas to come into contact with a metal having the fluoric gas and reactivity, a solid alkali metal and the like in order. CONSTITUTION:The discharge laser gas of an excimer laser generating device 1 is sent to a reactive metal, e. g. a filling tube 2 of Si or Fe. In such a case, a fluoric gas reacts to the metal and solid impurities are removed or are introduced to the next process together with a laser gas as gaseous impurities and the like. Then the laser gas is sent to a solid alkali filling tube 3 and active substances, e. g. SiF4, CO2 and the like are removed. Further, the laser gas is sent to a zeolite filling tube 4 and most of residual impurities or H2O and the like are removed. Diluted gases such as He or Ar, Xe and the like from which these impurities are removed are introduced in the excimer laser generating device 1 and are circulated. The principal ingredients such as F2, NF3 and the like which are removed otherwise are supplemented and are introduced in the laser generating device 1. The laser gas is thus purified and circulated efficiently and a lowering of laser output is suppressed in continuous oscillations which are performed for a long period. |
