| 摘要 |
An illumination system for EUV lithography is used for illuminating a predetermined illumination field (2) of an object surface with EUV radiation (4). The illumination system has a source for the EUV radiation (4). A first optical element (7) is used to generate secondary light sources in the illumination system. A surface, impacted by EUV radiation (4), of the first optical element (7) is divided into a plurality of first facet elements (8 to 11). The latter are each associated with partial beams (12 to 15) of the EUV radiation (4). A second optical element (20) at the location of the secondary light sources is impacted by EUV radiation (4) over an impactable area via the first optical element (7), which impactable surface is divided into a plurality of second facet elements (21 to 24). The latter are each associated with at least one of the first facet elements (8 to 11) impacting the respective second facet element (21 to 24) to generate the secondary light sources. The second optical element (20) is at least part of an optical arrangement which images the first optical element (8 to 11) in a plane predetermined by the object surface. At least selections of the first facet elements (8 to 11) are configured and oriented in such a way that they are imaged in one of at least two partial fields (31, 32) of the illumination field (2) by the optical arrangement. The partial fields (31, 32) make up the entire illumination field (2), and intersection between the partial fields, if it exists at all, is always smaller than each of the partial fields contributing to the intersection. An illumination system is produced in which changing between various illumination settings is possible even when a second optical element is used which has fewer facet elements compared to the prior art. |
