Characterisation of a liquid-xenon jet laser-plasma extreme-ultraviolet source

• A liquid-xenon-jet laser-plasma source for extreme-ultraviolet (EUV) and soft-x-ray generation has been characterized. Being a source candidate for EUV lithography (EUVL), we especially focus on parameters important for the integration of the source in EUVL systems. The deep-ultraviolet (DUV) out-of-band radiation (=120–400 nm) was quantified, to within a factor of two, using a flying-circus tool together with a transmission-grating spectrograph resulting in a total DUV conversion efficiency (CE) of ~0.33%/2sr. The size and the shape of the xenon plasma was investigated using an in-band-only EUV microscope, based on a spherical Mo/Si multilayer mirror and a charge-coupled device detector. Scalability of the source size from 20–270 µm full width at half maximum was shown. The maximum repetition-rate sustainable by the liquid-xenon-jet target was simulated by a double-pulse experiment indicating feasibility of >17 kHz operation. The xenon-ion energy distribution from the plasma was determined in a time-of-flight experiment with a Faraday-cup detector showing the presence of multi-kilo-electron-volt ions. Sputtering of silicon witness plates exposed to the plasma was observed, while a xenon background of >1 mbar was shown to eliminate the sputtering. It is concluded that the source has potential to meet the requirements of future EUVL systems.

Ämnesord

NATURVETENSKAP  -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

molybdenum

silicon

multilayers

plasma jets

ultraviolet lithography

ultraviolet radiation effects

time of flight spectra

plasma production by laser

ultraviolet sources

Plasma physics

Plasmafysik

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)