Patent ID: 8248577
Filing Date: 2012-08-21
Classification: G03F,H01L

Abstract:
1. A lithographic apparatus, comprising: a substrate table constructed to hold a substrate; a projection system configured to project a patterned radiation beam onto a target portion of a surface of the substrate; and a liquid confinement structure configured to contain liquid in a space between the nearest point, to the substrate, of an optical surface of the projection system and a bottom surface of the liquid confinement structure, the projection system optical surface, in use, contacting the liquid and having the patterned radiation beam pass through the optical surface, the liquid confinement structure having a further surface extending between the substrate and the nearest point of the optical surface, at least part of the further liquid confinement structure surface being at an angle with respect to the surface of the substrate, and the further liquid confinement structure surface at least in part defining the space laterally between the bottom surface of the liquid confinement structure and the nearest point of the projection system optical surface, wherein in a plane substantially parallel to the substrate and passing through the further liquid confinement structure surface, at a position closest to the substrate, the space has a cross-section having an area which is less than 1.5 times the area of the target portion, and wherein in a plane substantially parallel to the substrate and which intersects both the liquid confinement structure and a final element of the projection system, the periphery of the cross-section of the final element is substantially evenly surrounded by an inner periphery of the liquid confinement structure.