| 摘要 |
PURPOSE:To form a pattern having high resolution by exposure using oscillation beams having no wavelength fluctuation by employing excimer laser beams, which are cooled and a temperature of which is brought to a constant temperature, for an etalon as an optical interference filter for a change into a spectral-width narrow band. CONSTITUTION:When there are the local temperature rises of surfaces positioned in the laser beam path of synthetic silica glass boards 15 constituting an etalon, the surfaces are expanded in consideration of the in-plane distribution of the energy of laser beams. The parallelism of the synthetic silica glass boards is damaged remarkably in expansion regions, the interference effect of laser beams projected to or emitted from the region is reduced or quenched, and the etalon is not operated. Nozzles 2 are disposed onto one surface or both surfaces of an etalon body 1 shaped by laminating two glass boards 15, a gas for cooling the etalon is injected toward the incident and outgoing sections of laser beams, and the local or whole temperature rise of the etalon is inhibited, and the temperature of the etalon is changed into a constant temperature. According to the constitution, stable oscillation beams turned into a narrow band are acquired, and a fine pattern can be formed stably when the oscillation beams are used for excimer-laser reduction projection. |
