Development of 13.5 nm light source for nanolitography using plasma technologies V. Sergeev, V. Kapralov, A. Kostryukov, I. Miroshnikov Plasma physics chair, Physical Technical Faculty G. Shneerson, Yu. Adamian High voltage techniques chair, Electomechanical Faculty State Polytechnical University St. Petersburg

Outline Motivation Laser plasma based on solid Xe rod Laser plasma based on liquid droplet Xe jet Plasma discharge based on theta-pinch approach Summary

Motivation Industry requirements for profitable EUV source: Dimension – <1 mm Radiation power onto mask in ( =13,5 nm, ) range – 130 W Background: Temperature of Xe plasma – eV Demonstrated power (in 2 st) laser plasma – 2 W Demonstrated power (in 2 st) Z pinch plasma discharge – 150 W

Z-pinch source for 13.5 nanolitography From V.M. Borisov et al. Plasma physics report (2002) V. 28, No.10 pp.1-5 Merits: 1) Small radiation volume 2) Simplicity relative (to laser scheme) Problems: 1)Erosion of electrodes (debris) 2)Heat removal Spectrum range =13,5 nm, Power in 1.8 sr in countinous regime 17 W (60 W in 2 sr) Pulse frequency 1800 Hz Pulse duration 0.3 s Dimension 3 mm 1 mm

-pinch source for 13.5 nanolitography Merits: 1) No erosion problem 2) Smoothed thermal load problem Problems: 1)Larger radiation volume (mm range) Density cm -3 Temperature33 eV dB/dt10 6 T/s Dimension 3 mm 4 mm Conversion efficiency 0,7 % Spectrum range =13,5 nm, Pulse frequency 100 Hz Pulse duratuon 4 s Evaluated Power in countinous regime 50 W in 2 sr

Extruder of solid Xe rod Laser synchronization Light barrier Excimer laser Cryogenic vessel Developed to detect extruded solid H 2 rod d~1 mm Developed for tokamak plasma fuelling: H 2, Kr, Continuous solid Xe rod extruded behind optical system and ignited by pulsed laser Optical system for 13.2 nm lithography developed in Ioffe institute

Uniform droplet generation experiments From Foster et al. Rev. Sci. Instrum., Vol. 48, No. 6, June μm Liquid Hydrogen droplet generation: V~100 m/sec; 70 μm droplets at 10 5 /sec or 210 μm droplets at 2×10 4 /sec : Flow rate: cm 3 /sec For Xe doplets in EUV source is necessary: 1μg/pulse×5×10 3 pulse/sec=5×10 -3 g/sec 5×10 -3 g/sec / 3.52 g/cm 3 =0.0015cm 3 /sec

Vibrating nozzle Laser synchronization Light barrier Excimer laser Cryogenic vessel Developed to detect pellet injected into tokamak d~1 mm Developed for tokamak plasma fuelling: H 2, Kr, λ πd Raleigh instability Uniform series of liquid Xe droplets ignited by pulsed laser Optical system for 13.5 nm lithography developed in Ioffe institute

Summary Different ways of EUV source improvement have been considered Theta-pinch approach has high radiation ower values (size of radiation area? require simulation and experimental verification) Laser plasma based on solid Xe rod has technical simplicity (require experimental verification of absortion of laser power) Laser plasma based on liquid droplet Xe jet seems mostly attractive way for development of the EUV source