Lithographic apparatus and device manufacturing method

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 the substrate;
• and
• a liquid confinement structure configured to contain liquid in a space between a bottom surface of the liquid confinement structure and an element of the projection system immediately adjacent the substrate, the liquid confinement structure having a further surface extending between the substrate and the nearest point of an optical surface of the element to the substrate, the element optical surface, in use, contacting the liquid and having the patterned radiation beam pass through the optical surface, 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 element optical surface,
• wherein the cross-sectional geometrical shape of the space in a plane substantially parallel to the substrate changes from a first geometrical shape at a position furthest from the substrate to a second geometrical shape, that is not merely a uniform scaling of the first geometrical shape, at a position closest to the substrate, wherein at the position closest to the substrate the geometrical cross-sectional shape, area, or both, of the space in a plane passing through the further liquid confinement structure surface is substantially the same as that of the target portion, and
• wherein in a plane substantially parallel to the substrate and which intersects both the liquid confinement structure and the element, the periphery of the cross-section of the element is substantially evenly surrounded by an inner periphery of the liquid confinement structure.

A device manufacturing method comprising using a projection system to project on a target portion of a surface of a substrate a patterned beam of radiation, wherein a space laterally between a bottom surface of a liquid confinement structure and the nearest point of an optical surface of the projection system to the substrate is configured to be filled with liquid and is defined at least in part by a further surface of the liquid confinement structure, the further liquid confinement structure surface extending between the substrate and the nearest point of the optical surface of the projection system to the substrate, the projection system optical surface, in use, contacting the liquid and having the patterned radiation beam pass through the optical surface, and at least part of the further liquid confinement structure surface extending between the substrate and the nearest point of the optical surface is at an angle with respect to the surface of the substrate, and

• in a plane substantially parallel to the substrate at a position closest to the substrate and passing through the liquid confinement structure surface, the space has a cross-section having an area which is less than 1.5 times the area of the target portion, and
• in a plane substantially parallel to the substrate and which intersects both the liquid confinement structure and an optical element of the projection system immediately adjacent the substrate, the periphery of the cross-section of the element is substantially evenly surrounded by an inner periphery of the liquid confinement structure.

A device manufacturing method comprising using a projection system to project, on a target portion of a substrate, a patterned beam of radiation, wherein a liquid is provided in a space laterally between a bottom surface of a liquid confinement structure and the nearest point of an optical element of the projection system immediately adjacent to the substrate and which space is defined at least in part by a further surface of the liquid confinement structure, the further liquid confinement structure surface extending between the substrate and the nearest point of the optical element of the projection system to the substrate, the element, in use, contacting the liquid and having the patterned radiation beam pass through the optical element, and wherein the cross-sectional geometrical shape of the space in a plane substantially parallel to the substrate changes from a first geometrical shape at a position furthest from the substrate to a second geometrical shape, that is not merely a uniform scaling of the first geometrical shape, at a position closest to the substrate, wherein at the position closest to the substrate the cross-sectional geometrical shape, area, or both, of the space in a plane passing through the further liquid confinement structure surface is substantially the same as that of the target portion and wherein in a plane substantially parallel to the substrate and which intersects both the liquid confinement structure and the element, the periphery of the cross-section of the element is substantially evenly surrounded by an inner periphery of the liquid confinement structure.