Patent ID: 9442388
Filing Date: 2016-09-13
CPC Classification: G03F,Y10S

Claim Text:
1. A lithographic projection apparatus, comprising: a projection system configured to project a pattern from a patterning device onto a substrate, the projection system comprising an optical element through which the pattern is projected, the optical element having an essentially horizontal surface and a side surface at an oblique angle to the substantially horizontal surface; a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid; and a liquid confinement member configured to constrain liquid within the space, the liquid confinement member having a surface extending above the bottom surface of the optical element and facing the side surface of the optical element, wherein a gap between the surface of the liquid confinement member and the side surface of the optical element allows liquid to flow therein, wherein the optical element of the projection system has, on the side surface and/or essentially horizontal surface configured to be in contact with the liquid, a protective coating arranged to have liquid in contact therewith.