| 摘要 |
A facet mirror (11) for an illumination optical unit for projection lithography has a plurality of used facets (12) which in each case reflect an illumination light partial beam. The facet mirror (11) has at least one change subunit (161, 162, 163) having a plurality of change facets (12; 121, 121') arranged jointly on a facet carrier, which change facets can be positioned alternatively at the used location of exactly one used facet (12). This results in a facet mirror with which different illumination geometries or illumination settings can be set operationally reliably and stably. |
