Patent ID: 7379162

Claim:
A substrate holding apparatus which contacts an undersurface of a substrate and holds the substrate, at least a portion of a top surface of the substrate being immersed in liquid, said apparatus comprising: a vacuum chuck unit for supporting the substrate; and a plurality of exhaust ducts, arranged along a periphery of a substrate supporting surface of said vacuum chuck unit, for exhausting the liquid from each of a plurality of grooves provided in a multiplexed way from the periphery towards a center of the substrate supporting surface, wherein an exhaust pressure in an exhaust duct closer to a periphery of the substrate supporting surface is higher than that in an exhaust duct further from the periphery of the substrate supporting surface, wherein the plurality of exhaust ducts are used for pressures not greater than suction-holding pressure of the vacuum chuck unit, and wherein each of the plurality of exhaust ducts has a different exhaust pressure.