Patent ID: 7379155

Claim:
A lithographic apparatus comprising: an illuminator configured to condition a radiation beam; a support constructed to hold a patterning device, the patterning device configured to impart the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid, the liquid supply system comprising a liquid confinement structure configured to at least partly confine the liquid within the space; an outlet configured to remove a mixture of liquid and gas passing through a gap between the liquid confinement structure and the substrate; and an evacuation system configured to draw the mixture through the outlet, the evacuation system comprising a separator tank arranged to separate liquid from gas in the mixture and a separator tank pressure controller, connected to a non-liquid-filled region of the separator tank, configured to maintain a stable pressure within the non-liquid-filled region.