摘要 |
<p>A lithographic apparatus comprising a source of EUV radiation, an illumination system configured to condition a radiation beam, and a projection system configured to project the radiation beam onto a substrate, wherein the apparatus further comprises a filter configured to prevent or reduce the transmission of unwanted radiation and an apparatus configured to detect damage of the filter, wherein the damage detection apparatus comprises an antenna configured to receive radio waves and an analysis apparatus configured to determine the presence of filter damage based upon the received radio waves.</p> |