Lithographic apparatus and device manufacturing method

A lithographic apparatus comprising:

• an illuminator for conditioning a beam of radiation;
• a first support for supporting a patterning device, the patterning device serving to pattern the projection beam according to a desired pattern;
• a second support for supporting a substrate;
• a projection system for projecting the patterned beam onto a target portion of the substrate, the projection system comprising a lower surface for defining a working distance to said substrate;
• and
• at least one gas generator for generating a conditioned gas flow in a volume extending between said lower surface and said substrate, wherein said gas generator is arranged to generate a gas flow that is directed towards a volume of the projection system above said lower surface, and wherein said gas generator comprises a guiding element for guiding said gas flow to a lower volume generally located below the lower surface of said projection system.

A device manufacturing method comprising:

• patterning a beam of radiation;
• projecting the patterned beam of radiation onto a target portion of a substrate with a projection system;
• generating a conditioned gas flow in a volume extending between a lower surface of the projection system and the substrate;
• and
• guiding the gas flow in a generally downward direction and then to a direction generally parallel to the lower surface of the projection system.

A device manufacturing method comprising:

• patterning a beam of radiation;
• projecting the patterned beam of radiation onto a target portion of a substrate with a projection system;
• generating a conditioned gas flow in a volume extending between a lower surface of the projection system and the substrate;
• directing the gas flow towards a volume of the projection system above the lower surface;
• and
• guiding the gas flow to a lower volume generally located below the lower surface of the projection system.