USE OF A TOP LAYER ON A MIRROR FOR USE IN A LITHOGRAPHIC APPARATUS, MIRROR FOR USE IN A LITHOGRAPHIC APPARATUS, LITHOGRAPHIC APPARATUS COMPRISING SUCH A MIRROR AND DEVICE MANUFACTURING METHOD

摘要

A lithographic apparatus has a source (SO), an illumination system with a mirror, a support structure for patterning means, a substrate table and a projection system. The source (SO) is arranged to provide radiation of a desired wavelength, e.g., EUV. It generates a stream of undesired metal particles that are deposited to form smaller and larger nuclei on the mirror. The lithographic apparatus further has a heat source (38) to heat the mirror. Consequently, the surface mobility of the metal particles on the mirror is increased.