| 摘要 |
An object of this invention is to reduce even slight irregularities in illumination that occur after assembly of an optical system. To this end, in an exemplary illumination-optical system, a light source that emits extreme ultraviolet (EUV) light, a collimator, a fly's-eye mirror, and a condenser are positioned, in this stated order. A prescribed illumination area on the emission side of the condenser is irradiated with Köhler illumination. At least one unit mirror, among multiple unit mirrors of the fly's-eye mirror, is a correction mirror that has reflectivity irregularities. The reflectivity irregularities correct a portion of, or all, the illumination irregularities in the illumination area.
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