Method for in-situ dynamic protection of a surface and optical assembly

Abstract

In situ dynamic protection of an optical element surface against degradation includes disposing the optical element in an interior of an optical assembly for the FUV/VUV wavelength range and supplying at least one volatile fluorine-containing compound (A, B) to the interior for dynamic deposition of a fluorine-containing protective layer on the surface. The protective layer (7) is deposited on the surface layer by layer via a molecular layer deposition process. The compound includes a fluorine-containing reactant (A) supplied to the interior in a pulsed manner. A further reactant (B) is supplied to the interior also in a pulsed manner. An associated optical assembly includes an interior in which a surface is disposed, and at least one metering apparatus (123) that supplies a reactant to the interior. The metering apparatus provides a pulsed supply of the compound as a reactant (A, B) for layer by layer molecular layer deposition.

Dependencies are inferred from the claim text.