Low density targets for laser-produced-plasma (LPP) extreme ultraviolet light source with high-CE and toward high-repletion supply

In the present paper, we overview fabrication methods to produce density-controlled tin and xenon targets for generating extreme ultraviolet (EUV) light. The target can be classified as a mass-limited target. In the case of tin, EUV was relatively monochromatic, and its conversion efficiency was higher than bulk tin. Using the nano-template method, the cellular foam size was controlled by the template size. The density was 0.5 ~1.5 g/cm3. In the case of the 0.5 g/cm3 foam, its morphology was controlled by changing the ethanol content of the precursor tin solution. The morphology difference was useful to control the angular distribution of EUV radiation. SnO2 nanofiber, which is oriented low-density material, was fabricated continuously using a electrospinning method. The width and the shape of the fiber were controlled by optimizing precursor solution. A transparent film with tin and SnO2 elliptic spheres were prepared using liquid crystalline cellulose derivative. Low density xenon was prepared from liquid xenon using a swirl atomizer to produce a density of 0.2 g/cm3.