Abstract: The invention relates to an apparatus and a method for characterizing a microlithographic mask. According to one aspect, an apparatus according to the invention comprises at least one light source which emits coherent light, an illumination optical unit which produces a diffraction-limited light spot on the mask from the coherent light of the at least one light source, a scanning device, by use of which it is possible to implement a scanning movement of the diffraction-limited light spot relative to the mask, a sensor unit, and an evaluation unit for evaluating the light that is incident on the sensor unit and has come from the mask, an output coupling element for coupling out a portion of the coherent light emitted by the at least one light source, and an intensity sensor for capturing the intensity of this output coupled portion.

Abstract: The invention relates to an apparatus and a method for characterizing a microlithographic mask. According to one aspect, an apparatus according to the invention comprises at least one light source which emits coherent light, an illumination optical unit which produces a diffraction-limited light spot on the mask from the coherent light of the at least one light source, a scanning device, by use of which it is possible to implement a scanning movement of the diffraction-limited light spot relative to the mask, a sensor unit, and an evaluation unit for evaluating the light that is incident on the sensor unit and has come from the mask, an output coupling element for coupling out a portion of the coherent light emitted by the at least one light source, and an intensity sensor for capturing the intensity of this output coupled portion.

Abstract: A sealing system for a housing includes a first housing part and a second housing part. The first housing part includes a flange, in which a substantially vertically running through-opening is provided. The second housing part includes a fastener receptacle on its outer side, which is separated from its inner side by a wall of the second housing part. A sealing element is arranged between (i) contacting surfaces of the first housing part and the second housing part and (ii) the fastener receptacle. The first housing part rests on the second housing part in such a manner that the through-opening is arranged above the fastener receptacle and a fastener is inserted into the fastener receptacle through the through-opening.