&"
!# !$! "2 laser-produced plasmas
Atsushi Sasanuma, Reiho Amano#(#/("$(#, Goki Arai% -#$$"-#$"/#$, and Taisuke Miura2
1Utsunomiya
1
2Institute
University,
for Laser
Technology (ILT)
Utsunomiya
University
, 2HiLASE
Center,
■Abstract
■Summary
We develop the hybrid laser system with the sub-nanosecond laser and
TEA CO2&- ,'*&$5 ,.)*,)/ .# -#),.*/&- (#$"# ( ,"3*/&- -
. 10 & (".# )! μ' 1$&& , *),. .# *, &$'$(,3 2* ,$' (.&
, -/&.-)!.# 2., ' /&.,0$)& .-)/, -!,)'.# -#),.2 laser-produced
*&-'--�
We have demonstrated short pulse CO2 &- , 1$.# '*&$5 , -3-. ' . .# repetiton,. )!4$(.-/()'$3($0 ,-$.3�
 /&- /,.$)(1-0,$& !,)'
.)(-1$.##$"# ( ,"3*/&- �
(2) $"# 'qualitity was achieved (M2 does not measure yet,)�
■Background: CO2 laser-produced UTA plasmas
APPLIED PHYSICS LETTERS 91, 231501 2007
CO2 laser-produced 64Gd plasmas for 6.7 nm (beyond EUV)
Enhancement of extreme ultraviolet emission from a CO2 laser-produced
Sn plasma using a cavity target
Yoshifumi Ueno,a Georg Soumagne, Akira Sumitani, and Akira Endo
Received 15 February 2005; accepted 25 May 2005; published online 22 July 2005
Department of Energy and Environmental Science, Graduate School of Engineering,
and Center for Optical Research and Education (CORE), Utsunomiya University, Yoto 7-1-2,
Utsunomiya, Tochigi 321-8585, Japan
EUVA (Extreme Ultraviolet Lithography System Development Association), 1200 Manda, Hiratsuka,
Kanagawa 254-8567, Japan
Department of Electrical and Electronic Systems Engineering, Graduate School of Information Science
and Electrical Engineering, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan
1
Takeshi Higashiguchib
1
ȝP*G
Intensity (arb. units)
0.6
0.4
0.6
0.4
0.2
0.2
0
3
4
5
6
7
8
9
10 11 12
0
3
4
5
6
7
8
9
CO2
Nd:YAG
1
ȝP*G
0.8
0.8
Received 30 August 2007; accepted 12 November 2007; published online 4 December 2007
We demonstrated enhancement of in-band conversion efficiency CE at 13.5 nm of the extreme
ultraviolet EUV emission from a tin Sn cavity target irradiated by a CO2 laser pulse. Whereas a
planar Sn target produced an in-band CE of around 2%, the use of cavity targets significantly
enhanced the EUV emission energy and the EUV CE. An EUV CE of 4% was observed for a Sn
cavity target with a depth of 200 m which is one of the highest values ever reported. © 2007
American Institute of Physics. DOI: 10.1063/1.2820451
Intensity (arb. units)
Hiroki Tanaka, Atsushi Matsumoto, Kouzi Akinaga, Akihiko Takahashi,a and
Tatsuo Okada
Conversion efficiency (%)
APPLIED PHYSICS LETTERS 87, 041503 2005
Comparative study on emission characteristics of extreme ultraviolet
radiation from CO2 and Nd: YAG laser-produced tin plasmas
0.8
0.6
0.4
0.2
0
1010
10 11 12
1011
1012
Laser intensity (W/cm 2 )
Wavelength (nm)
Wavelength (nm)
1013
T. Higashiguchi et al., Optics Express 21, 31837 (2013).
■Setup & Results
CdTe pockels cell
Si mirror
Si mirror
λ/2 plate
f=1m
$
$
$
$
$
$
$
$
TFP
Nd:YAG laser
150 ps pulse
Intensity
Output
SiO2　lens
Ge substrate
Si mirror
ZnSe　lens
Without$QDswitch$(4.0$mJ,$250$ns)$$
Output
Inside Oscillator
Nd:YAG laser
150 ps pulse
Cu mirror
With$QDswitch$(1.5mJ,$15$ns)
Intensity TFP
$
f=1m
Ge substrate
Nd:YAG laser
10 ns pulse
Beam dumper
Inside Oscillator
1.2
Beam dumper
100
200
300
TIme [n
]
400
500
0
200
400
600
TIme [n
]
800
1000
CO2 laser
15 ns pulse
SiO2　lens
Nd:YAG laser
10 ns pulse
0.8
0.6
0.4
0.2
0
0
100
200
Time (ns)
"#!2 laser $#!#!! %2&"
200
160
Energy (mJ)
0
1
Intensity (arb. units)
ZnSe　lens
15 ns
10 ns
8 ns
5 ns
3 ns
120
80
40
0
1000
1100
1200
1300
Amplifier discharge voltage (V)
Characteristics of extreme ultraviolet
emission from mid-infrared
laser-produced rare-earth Gd plasmas
Takeshi Higashiguchi,1,∗ Bowen Li,2 Yuhei Suzuki,1 Masato
Kawasaki,1 Hayato Ohashi,1 Shuichi Torii,3 Daisuke Nakamura,4
Akihiko Takahashi,5 Tatsuo Okada,4 Weihua Jiang,6 Taisuke Miura,7
Akira Endo,7 Padraig Dunne,2 Gerry O’Sullivan,2 and Tetsuya
Makimura3
Acknowledgements
A part of this work was performed under the auspices of Ministry of Education, Culture, Science and
Technology, Japan (MEXT). We are also grateful to the Cooperative Research Center and the Venture
Business Laboratory (VBL) of Utsunomiya University for providing the laser system. One of the authors
(T.H) also acknowledges support from Research Foundation for Opto-Science and Technology.
300