Abstract: In some embodiments, the disclosure provides a method for setting an optical imaging property in a microlithographic projection exposure apparatus via which a mask can be imaged onto a substrate having a light-sensitive surface, wherein the substrate can be moved stepwise in a direction transversely with respect to an optical axis relative to a projection objective. The method can include introducing an immersion medium under a predetermined pressure and/or with a predetermined flow rate into at least one first interspace, wherein the at least one first interspace—as seen along the optical axis—is arranged within an illumination system and/or the projection objective and/or between the illumination system and the mask and/or the mask and the projection objective and/or the projection objective and the substrate. The method can also include monitoring an actual pressure and/or an actual flow rate of the immersion medium for deviation from the predetermined pressure and/or the predetermined flow rate.

Abstract: A method and a device for decontaminating optical surfaces, in particular for decontaminating the surfaces of beam-guiding optics employing UV-radiation in a cleansing atmosphere. The wavelength of the UV-radiation employed falls within a range where oxygen strongly absorbs and the cleansing atmosphere has an oxygen concentration less than that of air. The method and device have application to, e.g., cleaning the surfaces of the beam-guiding optics of microlithographic projection-exposure systems.

Abstract: A method and a device for decontaminating optical surfaces, in particular for decontaminating the surfaces of beam-guiding optics employing UV-radiation in a cleansing atmosphere. The wavelength of the UV-radiation employed falls within a range where oxygen strongly absorbs and the cleansing atmosphere has an oxygen concentration less than that of air. The method and device have application to, e.g., cleaning the surfaces of the beam-guiding optics of microlithographic projection-exposure systems.