Debris mitigation techniques for a Sn- and Xe-fueled EUV light source

Methods for mitigation of debris from a z-pinch plasma are investigated at the University of Illinois at Urbana-Champaign (UIUC). A source is used with either Sn or Xe fuels, which are known to have emission spectra peaks at 13.5nm [1]. The pinch plasma also ejects debris in the form of electrons, ions, neutral particles, macroscopic material, and out-of-band radiation. This debris can damage nearby mirror optics through heating, deposition, and erosion mechanisms. A spherical sector energy analyzer (ESA) is used to distinguish ion debris with respect to energy-to-charge-state ratio up to 13keV [2]. Combined with time-of-flight (TOF) information, the particular species of measured ions can be identified as well. A set of microchannel plates is used with an in-line E-field ion diverter to measure the flux of neutrally-charged atomic particles from the source. Using this method, the neutral flux is measured and the percentage of the ionized flux is noted. An effort is made to match this to theoretical values. A set of parallel plates is placed immediately beyond the debris mitigation tool and a voltage is applied in order to divert charged debris. The result is measured with the ESA.