Fluorescence radiation filter
AssigneeASML Netherlands B.V.
InventorsJohannes C Mulkens, Paul Van der Veen
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Abstract
The filter has alternating layers of relatively high and relatively low refractive index media. The layers are formed as a coating on an optical component in the projection lens system of a lithographic projection apparatus. The filter transmits radiation at a wavelength of 157 nm for exposing an image of a mask pattern on a resist-coated substrate while attenuating radiation resulting from fluorescence in optical components of the lithographic projection apparatus, caused by the imaging radiation, and which if not attenuated would reduce the contrast of the image exposed in the resist.
Claims17
A lithographic projection apparatus comprising:
- a radiation system constructed and arranged to supply a projection beam of electromagnetic radiation with a wavelength less than 160 nm;
- a first object table for holding a mask;
- a second object table for holding a substrate;
- a projection system constructed and arranged to provide a projection beam to image irradiated portions of the mask onto target portions of the substrate;
- and
- a filter, located in the projection beam path, the filter being constructed and arranged to attenuate fluorescence radiation with a wavelength longer than that of the projection beam.
A method of manufacturing a device comprising:
- providing a mask bearing a pattern to a first object table;
- providing a substrate provided with a radiation-sensitive layer to a second object table;
- irradiating portions of the mask and imaging said irradiated portions of the mask onto target portions of said substrate;
- and
- employing a filter, located in the projection beam path, to attenuate fluorescence radiation with a wavelength longer than that of the projection beam wherein the projection beam comprises radiation having a wavelength less than 160 nm.
Dependencies are inferred from the claim text.