X-RAY-PRODUCTION - 13 NM FROM LASER-PRODUCED PLASMAS FOR PROJECTION X-RAY-LITHOGRAPHY APPLICATIONS

X-ray production in the region approximately 13 nm from laser-produced plasmas has been investigated as a source for projection x-ray lithography. The dependence of x-ray conversion efficiency on target material, intensity, and pulse length has been studied by using a 0.53-mum laser with a maximum of 0.3 J. A conversion efficiency of 1% into a 0.3-nm bandwidth has been demonstrated for Sn targets at intensities of approximately 10(11) W/cm2 by using a 7.5-ns pulse. Intensity scaling suggests that laser spot size and two-dimensional expansion are important for optimizing x-ray production at these low-irradiation intensities.