Radiation characteristics of high repetition rate capillary Z-pinch EUV source

An extreme ultraviolet (EUV) source as a candidate for a light source in next generation lithography systems has been studied. A xenon capillary Z-pinch source was coupled with an all-solid-state magnetic pulse compression (MPC) generator. In order to evaluate the source performance, radiation characteristics such as radiation energy, spectrum and angular radiation distribution were observed, as well as the energy stability at high repetition rate operation. The xenon Z-pinch load was driven by a pulsed current of which peak current and pulse duration were approximately 20 kA and 275 ns, respectively. Changing the pressure condition in the capillary, it was understood that the highest on-axis EUV energy was 4.2 mJ/sr within 2 % bandwidth around 13.5 nm at low-repetition rate. Knowing the effective, usable solid angle of radiation at 34.5 W of EUV power was confirmed at 7 kHz