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Q: Quantenoptik
Q 23: Poster: Application of Short Pulses
Q 23.2: Poster
Thursday, April 5, 2001, 12:30–15:00, AT2
Optimization of the EUV yield from laser-produced plasma — •Stefan Düsterer, Wolfgang Ziegler, Christian Ziener, Heinrich Schwoerer, and Roland Sauerbrey — Inst. für Optik und Quantenelektronik, Uni Jena
Extreme ultraviolet (EUV) lithography is currently the most
promising approach to produce sub 50 nm structures for
computer chips on an industrial scale. Our goal is the
enhancement of the efficiency of laser-based EUV sources.
An intensive laser pulse focused onto a water droplet (Ø 20
µm) produces a plasma. The O+5 ions from the plasma
emit 13 nm EUV radiation.
The conversion efficiency (CE) from laser light in to EUV
radiation could be significantly (factor 2 to 7) increased
by adjusting the laser parameters to the droplet size.
The CE was was measured for laser pulse duration
from 200 fs to 6 ns
and for each pulse duration the pulse energy was varied
from 20 mJ to 200 mJ. A distinct maximum for the CE was
found for a pulse length of 120 ps and an energy of 50 mJ.
The position of both maxima can be explained by a theoretical
model.
We showed for the first time that the EUV CE for a certain
droplet volume shows a maximum for one certain pulse
duration and for one pulse energy.
This result is useful in designing a EUV source meeting
the high demands of the industry.