A novel method of filtering out atoms and small particulates, emitted from a laser plasma EUV radiation source, has been developed and experimentally characterized. The method consists of elimination of debris species by an optically transparent assembly of foils positioned in a buffer gas environment near the source. A high trapping efficiency is achieved due to retardation and scattering of particles in the gas and subsequent deposition on the foils. The method imposes no limitations of the radiation acceptance angle. The foil trap technique, a debris suppression method universally applicable for different EUVL radiation sources, has been investigated in combination with a fast rotating laser plasma target. A target unit with a disk edge velocity of up to 500 rn/s enabling nearly full elimination of large particulates, served as a source of different debris components for experiments on foil trapping atoms and sub-micron particulates. An integrated suppression coefficient of 500 has been measured for debris with sizes of up to a micrometer using a pilot trap cooled down to -90 °C. Extrapolation of this data to conditions when debris of sub-micron size only is produced, resulted in a suppression coefficient of 2000.

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