Laser oscillation apparatus, exposure apparatus, semiconductor device manufacturing method, semiconductor manufacturing factory, and exposure apparatus maintenance method

摘要

A laser oscillation apparatus includes a wavelength change unit for driving a wavelength selection element in a band-narrowing module and changing the oscillation wavelength of a laser beam to a target value, and an oscillation history memory for storing the oscillation state of the laser beam as an oscillation history. The wavelength change unit drives the wavelength selection element on the basis of the oscillation history and changes the oscillation wavelength of the laser beam to the target value.