Xenon discharge produced plasma radiation source for EUV lithography

EUV radiation with wavelengths of 11 to 14 nm is seen as the most promising candidate for a new lithographic technology. Compared to synchrotron radiation sources and laser produced plasmas, gas discharge produced plasma (GDP) sources for EUV radiation are expected to offer lower cost of ownership. Using xenon a broadband emission in the investigated wavelength range from 10 to 18 nm is observed. Very short current pulses, having a fast rise time with 85 ns or 140 ns duration and 20 kA amplitude, were applied across the xenon-filled z-pinch capillary (3 mm diameter and 5 mm length) to produce EUV radiation. A EUV radiation from the z-pinch plasma was characterized, which is based on the temporal behavior of EUV intensity and the pinhole images. Two maximum EUV radiations occur, which are sensitive to the xenon flow rate and the discharge current. The 1st radiation is relatively short duration while the 2nd radiation lasts as long as the 1st period of the current flows. EUV source size due to the 1st radiation is approximately 300 μm that is half of one due to the 2nd radiation.