Patent ID: 8237911

Claim:
A lithographic projection apparatus comprising: an optical assembly that projects an image onto a substrate; a stage assembly including a substrate table that supports the substrate adjacent to the optical assembly, a space between a final optical element of the optical assembly and the substrate being filled with an immersion liquid; a confinement member that forms at least a part of a boundary of the space and that confines the immersion liquid in the space, the confinement member spaced from the substrate table and encircling the final optical element of the optical assembly; and an insertion member removably insertable into the space between the confinement member and the substrate, the substrate table, or both, to divide the immersion liquid in the space into a first portion and a second portion, the first portion disposed between the final optical element and the insertion member with the confinement member and the insertion member confining the first portion of the immersion liquid, the second portion disposed between the insertion member and the substrate, the substrate table, or both, the insertion member keeping the final optical element in contact with the first portion of the immersion liquid when the substrate is moved away from being disposed adjacent to the optical assembly, wherein the immersion liquid in the second portion is removed via the confinement member while the insertion member is positioned between the confinement member and the substrate, the substrate table, or both.