| 摘要 |
PURPOSE:To provide a stable dust removing means to fluorine gas for removing dusts floating in laser medium gas in an excimer laser system which uses the fluorine gas as the laser medium gas. CONSTITUTION:A dust filter case 9 is coupled with a chamber 1 of an excimer laser and filters 13 are attached in the case 9. A gas flow, which passes through between main electrodes 3 and 4 and flows in the filters 13, is generated by making a fan 2 drive. A mother material which does not react to fluorine, a coating material or a passivation film, such as a stainless steel mesh filter subjected to fluoro passivation treatment, is used for the filters 13. Medium gas filtered by the filters 13 enters a window purging chamber and passes through opening parts of labyrinths 8 to return in the chamber 1. It is not caused that the transmittance of windows is reduced by a reaction product produced by a reaction of the medium gas with the filters and the output of a laser beam is reduced like a conventional method. |
