A Liquid-Xenon-Jet Laser-Plasma X-Ray and EUV Source

The laser-produced plasma is a compact and relatively inexpensive soft x-ray and extremeultraviolet (EUV) source. In this paper we describe a xenon liquid-jet laser-plasma source suitable for EUV lithography and proximity x-ray lithography (PXL). This specific source combines the advantages of the microscopic-liquid-jet target method and inert-gas, high-Z target material. EUV lithography at A ~ l l 1 4 nm is currently one of the strongest candidates to succeed deepultraviolet lithography for large-scale manufacturing [1-3]. Proximity x-ray lithography at A~I nm has, for example, found applications in low-volume manufacturing of MMICs [4]. Although synchrotrons are viable sources for both of tlwse short-wavelength lithography systems, the technology would benefit from compact sources with sufficient x-ray or EUV power. The laserproduced plasma is a compact source with the potential to scale to appropriate power levels. Other compact sources under development include zpinch, capillary discharge and plasma discharge [5]. Laser plasmas are attractive table-top sources duo to their small size, high brightness, high spatial stability and, potentially, high-repetition rate. However, with conventional bulk or tape targets, the operating time is limited, especially when high-repetition-rate lasers are used, since