Patent ID: 7978306

Claim:
A system, comprising: a substrate table constructed to hold a substrate, wherein the substrate has an unflatness or variation in thickness at an edge of the substrate; a surrounding structure surrounding the substrate table; a liquid confinement structure configured to at least partly confine a liquid within a space adjacent the substrate, or the substrate table, or the surrounding structure, or any combination of the foregoing; an actuator configured to move the substrate table with respect to the surrounding structure and/or move the surrounding structure with respect to the substrate table, at least in a direction perpendicular to a surface of the surrounding structure; and a controller configured to drive the actuator to move the substrate table with respect to the surrounding structure and/or move the surrounding structure with respect to the substrate table, to a position so that the surface of the substrate, when held on the substrate table, is substantially level with the surface of the surrounding structure at a location where and when the liquid is about to or does contact the surrounding structure from the substrate, or at a location where and when the liquid is about to or does contact the substrate from the surrounding structure.