Gas flushing system with recovery system for use in lithographic apparatus
AssigneeASML Netherlands B.V.
InventorErik R. Loopstra
Life of this patent
Estimating the term…
Abstract
In a lithographic apparatus using exposure radiation of a relatively short wavelength, e.g. 157 or 126 nm, a laminar flow of N2 is provided across parts of the beam path in or adjacent to moving components of the apparatus. The laminar flow is faster than the maximum speed of the moving components and the diffusion rate of air thereby minimizing the contamination of the N2 by mixing with air. Laminar flow may be ensured by providing partitions to divide the beam path into separate spaces, by covering rough or non-planar surfaces in components on or adjacent to the laminar flow and by providing aerodynamic members.
Claims15
A lithographic projection apparatus comprising:
- a radiation system constructed and arranged to supply a projection beam of radiation;
- a first object table for holding a mask;
- a second object table for holding a substrate;
- a projection system constructed and arranged to image an irradiated portion of the mask onto a target portion of the substrate;
- and
- a gas structure constructed and arranged to supply a substantially laminar flow of flushing gas across at least a part of a path of said projection beam to displace ambient air therefrom, said flushing gas being substantially non-absorbent of said radiation such that said substantially laminar flow of flushing gas traverses a substantially non-obstructed region in said projection apparatus,
- wherein said gas structure comprises:
- a supply of flushing gas,
- a gas flow regulator,
- an evacuator constructed and arranged to remove flushing gas from said part of said beam path, and
- a gas recovery system constructed and arranged to recover at least part of the flushing gas for further use in the apparatus.
A method of manufacturing a device comprising:
- providing a substrate having a radiation-sensitive layer in a projection apparatus;
- irradiating portions of a mask bearing a pattern with a projection beam of radiation and imaging said irradiated portions of the mask onto target portions of said substrate;
- providing flushing gas to flow in a substantially laminar flow across at least a part of a path of said projection beam to displace therefrom ambient air, said flushing gas being substantially non-absorbent of said radiation, and said laminar flow of flushing gas traversing a substantially non-obstructed region in said projection apparatus,
- evacuating said flushing gas from said at least part of the path of said projection beam, and
- recovering at least part of said flushing gas and reintroducing said at least part of said flushing gas across at least part of said substantially non-obstructed region.
A lithographic projection apparatus comprising:
- a radiation system constructed and arranged to supply a projection beam of radiation;
- a first object table for holding a mask;
- a second object table for holding a substrate;
- a projection system constructed and arranged to image an irradiated portion of the mask onto a target portion of the substrate;
- and
- a gas structure mounted to an extremity of at least one of said radiation system and said projection system, said gas structure is constructed and arranged to supply a laminar flow of flushing gas across at least a portion of a path of said projection beam, said flushing gas being substantially non-absorbent of said radiation, said gas structure comprises:
- an evacuator constructed and arranged to remove flushing gas from said part of said beam path in a vicinity of said extremity of said at least one of said radiation system and said projection system;
- and
- a gas recovery system constructed and arranged to recover at least part of the flushing gas and to reintroduce said at least part of the flushing gas into said projection apparatus.
Dependencies are inferred from the claim text.