摘要 |
In a lithographic apparatus, an illumination mode is set using a field mirror comprising a plurality of movable facets to direct radiation to selectable positions on a pupil facet mirror. In the event that a field facet mirror is defective and cannot be set to a desired position, another of the movable facet mirrors is set to a corrective position, different than its desired position, to at least partially ameliorate a deleterious effect of the defective facet mirror. |