| Abstract: | An apparatus for use with extreme ultraviolet (EUV) light comprising A) a
duct having a first end opening, a second end opening and an intermediate
opening intermediate the first end opening the second end opening, B) an
optical component disposed to receive EUV light from the second end
opening or to send light through the second end opening, and C) a source
of low pressure gas at a first pressure to flow through the duct, the gas
having a high transmission of EUV light, fluidly coupled to the
intermediate opening. In addition to or rather than gas flow the
apparatus may have A) a low pressure gas with a heat control unit
thermally coupled to at least one of the duct and the optical component
and/or B) a voltage device to generate voltage between a first portion
and a second portion of the duet with a grounded insulative portion
therebetween. |