US 7,476,491 B2
Lithographic apparatus, gas supply system, method for purging, and device manufacturing method and device manufactured thereby
Antonius Johannes Van Der Net, Tilburg (Netherlands); Paul Van Der Veen, Waalre (Netherlands); and Yuri Johannes Gabriel Van De Vijver, Best (Netherlands)
Assigned to ASML Netherlands B.V., Veldhoven (Netherlands)
Filed on Sep. 15, 2004, as Appl. No. 10/941,017.
Prior Publication US 2006/0055900 A1, Mar. 16, 2006
Int. Cl. G03F 7/20 (2006.01)
U.S. Cl. 430—302  [430/311; 355/30; 355/53] 10 Claims
OG exemplary drawing
 
1. A lithographic apparatus comprising:
an illumination system for providing a beam of radiation;
a support structure for supporting a patterning device, the patterning device serving to impart the beam of radiation with a pattern in its cross-section;
a substrate table for holding a substrate;
a projection system for projecting the patterned beam onto a target portion of the substrate; and
a gas supply system for supplying a purge gas comprising oxygen to a plurality of spaces in said apparatus, the gas supply system being arranged so that the purge gas being supplied to each of the plurality of spaces is a premixed purge gas mixture composed by the gas supply system for each of the plurality of spaces on the basis of a predetermined relationship that relates a desired amount of oxygen in the premixed purge gas mixture to the respective space to which that premixed purge gas mixture is supplied.