| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an improved or alternative spectral purity filter. <P>SOLUTION: The spectral purity filter includes a plurality of apertures penetrating a member. The aperture is formed to suppress radiation having a first wavelength, and transmit at least a part of radiation having a second wavelength. The second wavelength of the radiation is shorter than the first wavelength of the radiation. A first region of the spectral purity filter has a first structure that provides a first radiation transmission profile to the radiation, having the first wavelength and the radiation having the second wavelength, and a second region of the spectral purity filter has a second different structure to provide a second different radiation transmission profile to the radiation, having the first wavelength and the radiation having the second wavelength. <P>COPYRIGHT: (C)2011,JPO&INPIT |
