TY - JOUR
T1 - Spectral characterization of an industrial EUV light source for nanolithography
AU - Torretti, Francesco
AU - Liu, Fei
AU - Bayraktar, Muharrem
AU - Scheers, Joris
AU - Bouza, Zoi
AU - Ubachs, W.
AU - Hoekstra, R.
AU - Versolato, Oscar
N1 - IOP deal
PY - 2019/11/28
Y1 - 2019/11/28
N2 - The emission spectra from an industrial, droplet-based, laser-produced plasma, extreme ultraviolet light source for nanolithography are here presented and analyzed. The dependence of spectral features on the CO2-drive-laser intensity is studied by changing the beam spot size at constant pulse energy and duration. We characterize the spectrum by fitting the results of atomic structure calculations to the short-wavelength region (7-11 nm), where the contributions from various charge states can be resolved, and obtain the relative contributions of charge states Sn9+-Sn15+. These relative contributions are compared to charge state populations as calculated with the non-equilibrium plasma kinetics code FLYCHK. The calculations are shown to be in good qualitative agreement with the results, showing that the effective plasma temperature, and with it, the shape of the unresolved, main emission feature at 13.5 nm, is a remarkably weak function of laser intensity under this source normal operating conditions.
AB - The emission spectra from an industrial, droplet-based, laser-produced plasma, extreme ultraviolet light source for nanolithography are here presented and analyzed. The dependence of spectral features on the CO2-drive-laser intensity is studied by changing the beam spot size at constant pulse energy and duration. We characterize the spectrum by fitting the results of atomic structure calculations to the short-wavelength region (7-11 nm), where the contributions from various charge states can be resolved, and obtain the relative contributions of charge states Sn9+-Sn15+. These relative contributions are compared to charge state populations as calculated with the non-equilibrium plasma kinetics code FLYCHK. The calculations are shown to be in good qualitative agreement with the results, showing that the effective plasma temperature, and with it, the shape of the unresolved, main emission feature at 13.5 nm, is a remarkably weak function of laser intensity under this source normal operating conditions.
KW - UT-Hybrid-D
U2 - 10.1088/1361-6463/ab56d4
DO - 10.1088/1361-6463/ab56d4
M3 - Article
VL - 53
JO - Journal of physics D: applied physics
JF - Journal of physics D: applied physics
SN - 0022-3727
IS - 5
M1 - 055204
ER -