Lithographic projection apparatus, device manufacturing method and device manufactured thereby
AssigneeASML Netherlands B.V.
InventorsWillem Van Schaik, Bastiaan Matthias Mertens, Hans Meiling, Norbertus Benedictus Koster
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Abstract
In-situ cleaning of optical components for use in a lithographic projection apparatus can be carried out by irradiating a space within the apparatus containing the optical component with UV or EUV radiation having a wavelength of less than 250 nm, in the presence of molecular oxygen. Generally, the space will be purged with an ozoneless purge gas which contains a small amount of molecular oxygen in addition to the usual purge gas composition. The technique can also be used in an evacuated space by introducing a low pressure of molecular oxygen into the space.
Claims5
A device manufacturing method comprising:
- projecting a patterned beam of radiation having a wavelength of 250 nm or less onto a target portion of a layer of radiation-sensitive material on a substrate, and
- irradiating a space containing an optical component of a lithographic projection apparatus which is positioned to interact with the projection beam with the projection beam and supplying to said space a purge gas comprising molecular oxygen at a total partial pressure of from 1×10−4 Pa to 1 Pa.
Dependencies are inferred from the claim text.