| 摘要 |
An illumination optical unit (7) for EUV projection lithography serves to illuminate an object field (8) with illumination light (3). An object (19) to be imaged, which is displaceable in an object displacement direction (y), is arrangeable in the object field (8). A transmission optical unit (14) images field facets of a field facet mirror (5) in a manner superposed on one another into the object field (8) by way of illumination channels, which each have assigned to them one of the field facets and one pupil facet of a pupil facet mirror (10). The superposition optical unit (14) has at least two mirrors (12, 13) for grazing incidence, which are arranged downstream of the pupil facet mirror (10). The mirrors (12, 13) for grazing incidence produce an illumination angle bandwidth of an illumination light overall beam (3G), composed of the illumination channels, in the object field (8), which bandwith is smaller for a plane of incidence (yz) parallel to the object displacement direction (y) than for a plane (xz) perpendicular thereto. What emerges is an illumination optical unit, by means of which a projection optical unit can be adapted to a configuration of an EUV light source for the illumination light. |
