OPTICAL SYSTEM AND MULTI FACET MIRROR

摘要

An optical system of a microlithographic projection exposure apparatus comprises a multi facet mirror (26) having a support plate (28) and a plurality of mirror facets (32). Each mirror facet comprises a mirror substrate (34) and a reflective coating (36) applied thereon, and is attached to the support plate (28). Actuators (48) are provided that induce a deformation of the support plate (28). The deformation necessarily changes the orientation and/or position, but not the shape, of at least two mirror facets (32). In this way aberrations can be corrected.