Abstract: A method and apparatus for monitoring a level of silicon dioxide in a liquid and removing the silicon dioxide using polishers is disclosed. In an embodiment, two polishers that absorb carbon dioxide and silicon dioxide, but which have a greater affinity for carbon dioxide, are placed in series along a conduit containing the liquid for use in an immersion lithographic apparatus. The upstream polisher absorbs carbon dioxide and silicon dioxide until it is saturated, at which point it desorbs the silicon dioxide in preference for the carbon dioxide. Silicon dioxide continues down the conduit and is absorbed by the downstream polisher. Once the upstream polisher is saturated with carbon dioxide, carbon dioxide present in the liquid flows downstream where it is absorbed by the downstream polisher. A sensor between the polishers senses the presence of carbon dioxide and initiates a request for the one or more of polishers to be cleaned or replaced.

Abstract: A method and apparatus for monitoring a level of silicon dioxide in a liquid and removing the silicon dioxide using polishers is disclosed. In an embodiment, two polishers that absorb carbon dioxide and silicon dioxide, but which have a greater affinity for carbon dioxide, are placed in series along a conduit containing the liquid for use in an immersion lithographic apparatus. The upstream polisher absorbs carbon dioxide and silicon dioxide until it is saturated, at which point it desorbs the silicon dioxide in preference for the carbon dioxide. Silicon dioxide continues down the conduit and is absorbed by the downstream polisher. Once the upstream polisher is saturated with carbon dioxide, carbon dioxide present in the liquid flows downstream where it is absorbed by the downstream polisher. A sensor between the polishers senses the presence of carbon dioxide and initiates a request for the one or more of polishers to be cleaned or replaced.

Abstract: A lithographic apparatus is disclosed including a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid, an outlet configured to remove a mixture of liquid and gas passing through a gap between a liquid confinement structure of the liquid supply system and the substrate, and an evacuation system configured to draw the mixture through the outlet, the evacuation system having 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.

Abstract: A substrate table of an immersion lithographic apparatus is disclosed which comprises a barrier configured to collect liquid. The barrier surrounds the substrate and is spaced apart from the substrate. In this way any liquid which is spilt from the liquid supply system can be collected to reduce the risk of contamination of delicate components of the lithographic projection apparatus.