EUV LIGHT SOURCE WITH SPECTRAL PURITY FILTER AND POWER RECYCLING

摘要

A plasma-generated EUV light source uses an EUV-diffracting collection mirror (103) to channel spectrally pure in-band radiation through an intermediate-focus aperture (105) and through EUV illumination optics. Out-of-band radiation (1102) is either undiffracted by the collection mirror or is diffractively scattered away from the aperture. The undiffracted portion, plus plasma-emitted radiation that does not intercept the collection mirror, can be efficiently recycled back to the plasma (102) via retroreflecting mirrors (1101;1103), cat's-eye reflectors, or corner-cube reflectors, to enhance generation of in-band EUV radiation by the plasma.