In recent years, as semiconductor processes become finer, transfer patterns for use in photolithographies of semiconductor processes have rapidly become finer. In the next generation, microfabrication at 70 nm to 45 nm, and further, microfabrication with 32 nm or less will be demanded. In order to meet the demand for microfabrication at 32 nm or less, for example, the development of an exposure apparatus in which an apparatus for generating extreme ultraviolet (EUV) light at a wavelength of approximately 13 nm is combined with a reduced projection reflective optics is expected.
As the apparatus for generating EUV light, three types of apparatuses have been proposed, which include a Laser Produced Plasma (LPP) type apparatus using plasma generated by irradiating a target material with a laser beam, a Discharge Produced Plasma (DPP) type apparatus using plasma generated by electric discharge, and a Synchrotron Radiation (SR) type apparatus using synchrotron radiation.