Mass-limited Sn target irradiated by dual laser pulses for an extreme ultraviolet lithography source.
A thin Sn film was investigated as a mass-limited target for an extreme ultraviolet (EUV) lithography source. It was found that those energetic ions that are intrinsic with the mass-limited Sn target could be efficiently mitigated by introducing a low-energy prepulse. High in-band conversion efficiency from a laser to 13.5 nm EUV light could be obtained using an Sn film with a thickness down to 30 nm when irradiated by dual laser pulses. It was shown that the combination of dual pulse and inert Ar gas could fully mitigate ions with a low ambient pressure nearly without the penalty of the absorption of the EUV light.
Tao
Y
Y
Department of Mechanical and Aerospace Engineering and the Center for Energy Research, University of California, La Jolla 92093-0438, USA. yetao@ucsd.edu
Tillack
M S
MS
Harilal
S S
SS
Sequoia
K L
KL
Burdt
R A
RA
Najmabadi
F
F