| 摘要 |
PURPOSE:To reduce the adverse effect inflicted on a bright line spectrum and to obtain an exposing device having high resolving power by a method wherein a suitable filter is inserted into a part of the illumination system with which a projection optical system is illuminated, and a continuous spectrum is effectively cut. CONSTITUTION:The luminous flux emitted from a light source 2 is condensed on the field lens 3 arranged in the vicinity of the second focus by an oval mirror. The incidence angle of each luminous flux which is made incident on a filter element 5 is made small in such a manner that the center luminous flux in a field lens 3 becomes almost a parallel light by the first capacitor lens. After passing through a filter element 5, the luminous flux is introduced to an optical integrator 8. The filter element 5 is composed of a multilayer film which transmits the luminous flux having the narrow wavelength range of bright line spectrum necessary for projection and exposure, but it does not transmit other spectrum lights. As a result, a continuous spectrum can be cut effectively, and the adverse effect inflicting on the bright-line spectrum can be reduced. |
