Patent ID: 7026629
Filing Date: 2006-04-11
Classification: B82Y,G03F

Abstract:
1. A lithographic projection apparatus, comprising: a radiation system constructed and arranged to provide a beam of radiation; a support constructed and arranged to support a patterning device, the patterning device constructed and arranged to pattern the beam according to a desired pattern; a substrate table constructed and arranged to hold a substrate; a projection system constructed and arranged to project the patterned beam onto a target portion of the substrate; a plasma source constructed and arranged to produce extreme ultraviolet radiation, which plasma source is a part of the radiation system; a first space containing only the plasma source and a source gas from the plasma source; and a second space separated from the first space by a wall containing a beam aperture, the second space containing a buffer gas which is different from the source gas; wherein the pressure in the second space is less than or approximately equal to the pressure in the first space and the beam of radiation passes through the first and second spaces.