Patent ID: 9182678
Filing Date: 2015-11-10
Classification: G03B,G03F

Abstract:
1. A lithographic apparatus comprising: a projection system configured to project a patterned radiation beam onto a target portion of a substrate, the projection system having a final element; a barrier member surrounding a space between the projection system and, in use, the substrate, to define in part with the final element a reservoir for a first liquid, the barrier member being spaced from the final element to define a gap therebetween; and a seal between a radially outer surface of the final element and a radially outer surface of the barrier member, the seal being configured to substantially prevent a gas from flowing past the seal towards or away from the reservoir of first liquid, the seal comprising a second liquid different from the first liquid, and the second liquid arranged to be located at least in part between a substantially horizontal surface of the barrier member and a facing surface of the final element and/or between a substantially horizontal surface of the final element and a facing surface of the barrier member.