Abstract: In a method for determining the life of a laser light source for use with an exposure apparatus using KrF or ArF excimer laser as a light source for exposure, the method for determining the life of the laser light source is implemented by subjecting an excimer laser light source to single oscillation by blocking a pulse light, acquiring data relating to plural parameters for learning a periodical variation of the excimer laser light source and its structuring parts through an interface, and determining the life of the excimer laser light source on the basis of the data acquired. Those data is acquired on a regular basis in accompany with the work for exchanging gases at the time of exchanging gases for the excimer laser light source.

Abstract: In a method for determining the life of a laser light source for use with an exposure apparatus using KrF or ArF excimer laser as a light source for exposure, the method for determining the life of the laser light source is implemented by subjecting an excimer laser light source to single oscillation by blocking a pulse light, acquiring data relating to plural parameters for learning a periodical variation of the excimer laser light source and its structuring parts through an interface, and determining the life of the excimer laser light source on the basis of the data acquired. Those data is acquired on a regular basis in accompany with the work for exchanging gases at the time of exchanging gases for the excimer laser light source.

Abstract: A laser apparatus comprises a plurality of laser beam sources which use, as laser media, mixed gases containing at least one common gas component; at least one common gas supply source for supplying, to the respective laser beam sources, the common gas component for constituting the mixed gases; and one or more gas flow amount-adjusting units for adjusting flow amounts of the common gas component supplied from the common gas supply source and other gas components for constituting the mixed gases so that the gas components are supplied to the respective gas laser beam sources. It is unnecessary to provide gas tanks for each of the laser beam sources. The arrangement of the gas supply equipment is simplified, and the safety is improved. A plurality of the laser apparatuses are preferably installed to a circuit element production line provided with a plurality of exposure apparatuses.