Lithographic apparatus, device manufacturing method, and optical component
AssigneeASML Netherlands B.V.
InventorLevinus Bakker
Life of this patent
Estimating the term…
Abstract
An optical component for use in a lithographic apparatus. The optical component includes an optical element having an optical surface for reflecting electromagnetic radiation, and a protective zone covering the optical surface. The protective zone is provided with a material that substantially protects the optical surface against sputtering when the optical component is in use. The material has a refractive index that approximately equals unity for at least a predetermined wavelength of electromagnetic radiation to which the optical surface is exposed.
Claims33
An optical component for use in a lithographic apparatus, the optical component comprising:
- an optical element having an optical surface for reflecting electromagnetic radiation;
- and
- a protective zone covering the optical surface, the protective zone being provided with a material that substantially protects the optical surface against sputtering when the optical component is in use,
- wherein the material has a refractive index that approximately equals unity for at least a predetermined wavelength of electromagnetic radiation to which the optical surface is exposed.
A lithographic apparatus comprising:
- an illumination system configured to condition a radiation beam;
- a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;
- a substrate table constructed to hold a substrate;
- a projection system configured to project the patterned radiation beam onto a target portion of the substrate;
- and
- an optical component in the illumination system or the projection system comprising
- an optical element having an optical surface for reflecting electromagnetic radiation;
- and
- a protective zone covering the optical surface, the protective zone being provided with a material dimensioned so that in use, the optical surface is substantially protected against sputtering,
- wherein the material has a refractive index that approximately equals unity for at least a predetermined wavelength of electromagnetic radiation to which the optical surface is exposed.
A device manufacturing method comprising:
- conditioning a radiation beam with an illumination system;
- patterning the radiation beam with a patterning device;
- and
- projecting the patterned radiation beam onto a substrate,
- wherein the illumination system comprises an optical component that is used in said conditioning the radiation beam, the optical component comprising an optical element having an optical surface for reflecting electromagnetic radiation;
- and
- a protective zone covering the optical surface, the protective zone being provided with a material that substantially protects the optical surface against sputtering during said conditioning,
- wherein the material has a refractive index that approximately equals unity for at least a predetermined wavelength of electromagnetic radiation to which the optical surface during said conditioning.
Dependencies are inferred from the claim text.