| 摘要 |
PROBLEM TO BE SOLVED: To provide an excimer laser apparatus in which the injection interval of halogen gas is expanded, in which the cause of the instability of a laser oscillation is reduced and in which the contamination of an optical system can be discriminated. SOLUTION: In an excimer laser apparatus, the laser output of a laser oscillation container 2 is detected 4, the charging voltage of a high-voltage power supply 10 is controlled 14 so as to obtain a constant laser output, and halogen gas 7 is injected into the laser oscillation container when the charging voltage reaches a predetermined set voltage value by a comparison circuit 17. In the excimer laser apparatus, a second set voltage value which is smaller than the predetermined set voltage value is set, and the injection of the halogen gas is finished when the inversion transition of the charging voltage does no exceed the second set voltage value by comparison circuits 20, 21 in the injection of the halogen gas. In addition, the excimer laser apparatus is provided with the injection control part, of the halogen gas, which finishes the injection of the halogen gas when the inversion transition of the charging voltage exceeds the second set voltage value. |
