Dual stage lithographic apparatus and device manufacturing method

A stage apparatus for a lithographic apparatus, the lithographic apparatus comprising a projection system configured to project radiation onto a substrate and a liquid confinement structure configured to at least partly confine a liquid in a space underneath a final element of the projection system, the stage apparatus comprising:

• a first movable stage configured to hold the substrate, the first movable stage having an upper surface;
• a second stage movable with respect to the first stage;
• an encoder system comprising an encoder measurement surface and an encoder head cooperating with the encoder measurement surface, the encoder system configured to measure a position of the first stage in at least a first direction as part of exposure, using radiation from the projection system, of the substrate when supported by the first stage and configured to have at least part of the encoder system located above the upper surface during the exposure;
• an interferometer system configured to measure a position of the first stage;
• and
• a positioning system configured to control movement of the first stage and the second stage together relative to the liquid confinement structure such that the liquid crosses and contacts a first edge of the first stage and an opposing second edge of the second stage and such that liquid in the liquid confinement structure is transferred from being confined from underneath by the substrate when supported by the first stage, or the first stage, or both, to being confined from underneath by the second stage.

A device manufacturing method, comprising:

• at least partly confining liquid in a space underneath a projection system;
• measuring a position, in at least a first direction, of a first stage holding a substrate using an encoder system comprising an encoder measurement surface and an encoder head cooperating with the encoder measurement surface, wherein at least part of the encoder system is located above the first stage during the measuring;
• measuring a position of the first stage using an interferometer system;
• and
• after projecting a beam of radiation from the projection system through the liquid onto the substrate, jointly moving the first stage with the second stage such that confinement of liquid in the space from underneath by the first stage, the substrate, or both, is replaced by confinement of liquid in the space from underneath by the second stage.

A stage apparatus for a lithographic apparatus, the lithographic apparatus comprising a projection system configured to project radiation onto a substrate and a liquid confinement structure configured to at least partly confine a liquid in a space underneath a final element of the projection system, the stage apparatus comprising:

• a first movable stage configured to hold the substrate;
• a second stage movable with respect to the first stage;
• an optical encoder system configured to measure a position in at least a first direction of at least the first stage as part of exposure, using radiation from the projection system, of the substrate when supported by the first stage, the encoder system comprising a first part arranged to be located above the first stage during the exposure and a second part located in or on the first stage, wherein the first part is sized so as to be able to simultaneously span over the first and second stages;
• and
• a positioning system configured to control movement of the first stage and the second stage together relative to the liquid confinement structure such that the liquid crosses and contacts a first edge of the first stage and an opposing second edge of the second stage and such that liquid in the liquid confinement structure is transferred from being confined from underneath by the substrate when supported by the first stage, or the first stage, or both, to being confined from underneath by the second stage.