US 12,292,696 B2
Fluid purging system, projection system, illumination system, lithographic apparatus, and method
José Nilton Fonseca Junior, Hamburg (DE); Franciscus Johannes Leonardus Heutz, Dommelen (NL); Zhuangxiong Huang, Eindhoven (NL); and Ferdy Migchelbrink, Veldhoven (NL)
Assigned to ASML Netherlands B.V., Veldhoven (NL)
Appl. No. 18/008,409
Filed by ASML Netherlands B.V., Veldhoven (NL)
PCT Filed Apr. 30, 2021, PCT No. PCT/EP2021/061374
§ 371(c)(1), (2) Date Dec. 5, 2022,
PCT Pub. No. WO2021/244808, PCT Pub. Date Dec. 9, 2021.
Claims priority of application No. 20178213 (EP), filed on Jun. 4, 2020.
Prior Publication US 2023/0205102 A1, Jun. 29, 2023
Int. Cl. G03F 7/20 (2006.01); G02B 27/00 (2006.01); G03F 7/00 (2006.01)
CPC G03F 7/70933 (2013.01) [G02B 27/0006 (2013.01); G03F 7/70833 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A fluid purging system for an optical element, comprising:
a ring formed of a body entirely surrounding the optical element, the ring defining a space radially inwards thereof and adjacent to the optical element, the ring formed by at least one first wall portion and at least one second wall portion, wherein an average height of the first wall portion is greater than an average height of the second wall portion;
a fluid supply system positioned radially outwards of the ring and configured to supply fluid to pass over the at least one second wall portion to the space; and
wherein the at least one second wall portion has a height changing in a radial direction.