摘要:
An optical assembly is mounted in a projection exposure apparatus (101) for EUV microlithography and includes at least one vacuum chamber (70, 71, 68a), at least one optical element (6, 7; 65, 66; 63) arranged in the vacuum chamber (70, 71, 68a), the optical element (6, 7; 65, 66; 63) having an optical surface (18) arranged to be impinged upon by a useful beam bundle (3) of the projection exposure apparatus (101), and a cleaning device (72) configured to clean the optical surface (18). The cleaning device (72) is configured to perform particle cleaning of the optical surface (18) at a gas pressure within the vacuum chamber (70,71, 68a) which is higher than a vacuum pressure (po) for performing an exposure operation with the projection exposure apparatus (101). As a result, optical elements having respective optical surfaces arranged to be impinged upon by a useful beam bundle can be cleaned reliably of foreign particles.
摘要:
A lithographic apparatus includes an illumination system configured to condition a beam of radiation, and a support structure configured to support a patterning device. The patterning device is configured to impart a pattern to the beam of radiation. The apparatus includes a patterning device cleaning system configured to provide an electrostatic force to contaminant particles that are on the patterning device and that are electrically charged by the beam of radiation, in order to remove the contaminant particles from the patterning device.