Patent ID: 8173975
Filing Date: 2012-05-08
Classification: B82Y,G03F

Abstract:
1. A method for removing contaminant particles produced by a radiation source during generation of short-wave radiation having a wavelength of up to approximately 20 nm for illuminating an object, the method comprising the act of: guiding between the radiation source and the particle trap a first gas at a first side of a particle trap arranged across an opening in a wall of a chamber; introducing a second gas into the chamber at a second side of the particle trap, wherein the first side is different from the second side and the object receives the short-wave radiation from the second side; and adjusting a pressure of the second gas to be at least as high as a pressure of the first gas so that the second gas flows from the second side to the first side, wherein the second gas is different from the first gas and the second side does not include the first gas.