Patent attributes
A lithographic apparatus includes a liquid supply system to supply an immersion liquid between a downstream lens of a projection system of the lithographic apparatus and a substrate. The lithographic apparatus further includes a closing element to close an underside of the liquid supply system thus preventing leaking of the immersion liquid from the liquid supply system when the substrate is removed from the underside of the liquid supply system. According to an aspect of the invention, an inductive sensor may be used to measure a position of the closing element. The inductive sensor may include an eddy current sensor. A metal foil or other conductive layer may be applied to the closing element. According to an aspect of the invention, a fast return of the closing disc into the holder is now made possible making use of the position of the closing disc as established with the inductive sensor.
