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Title: Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source

Abstract

A regenerative tin liquid microjet target was developed for a high average power extreme ultraviolet (EUV) source. The diameter of the target was smaller than 160 {mu}m and good vacuum lower than 0.5 Pa was maintained during the operation. A maximum EUV conversion efficiency of 1.8% at the Nd:yttrium-aluminum-garnet laser intensity of around 2x10{sup 11} W/cm{sup 2} with a spot diameter of 175 {mu}m (full width at half maximum) was observed. The angular distribution of the EUV emission remained almost isotropic, whereas suprathermal ions mainly emerged toward the target normal.

Authors:
; ;  [1]
  1. Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki 889-2192 (Japan)
Publication Date:
OSTI Identifier:
20953406
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 3; Other Information: DOI: 10.1063/1.2712787; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALUMINIUM; ANGULAR DISTRIBUTION; EMISSION; EXTREME ULTRAVIOLET RADIATION; GARNETS; IONS; LASER-PRODUCED PLASMA; LASERS; LIQUIDS; PLASMA PRODUCTION; TIN; YTTRIUM

Citation Formats

Higashiguchi, Takeshi, Hamada, Masaya, and Kubodera, Shoichi. Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source. United States: N. p., 2007. Web. doi:10.1063/1.2712787.
Higashiguchi, Takeshi, Hamada, Masaya, & Kubodera, Shoichi. Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source. United States. doi:10.1063/1.2712787.
Higashiguchi, Takeshi, Hamada, Masaya, and Kubodera, Shoichi. Thu . "Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source". United States. doi:10.1063/1.2712787.
@article{osti_20953406,
title = {Development of a liquid tin microjet target for an efficient laser-produced plasma extreme ultraviolet source},
author = {Higashiguchi, Takeshi and Hamada, Masaya and Kubodera, Shoichi},
abstractNote = {A regenerative tin liquid microjet target was developed for a high average power extreme ultraviolet (EUV) source. The diameter of the target was smaller than 160 {mu}m and good vacuum lower than 0.5 Pa was maintained during the operation. A maximum EUV conversion efficiency of 1.8% at the Nd:yttrium-aluminum-garnet laser intensity of around 2x10{sup 11} W/cm{sup 2} with a spot diameter of 175 {mu}m (full width at half maximum) was observed. The angular distribution of the EUV emission remained almost isotropic, whereas suprathermal ions mainly emerged toward the target normal.},
doi = {10.1063/1.2712787},
journal = {Review of Scientific Instruments},
number = 3,
volume = 78,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • We demonstrated a low-debris, efficient laser-produced plasma extreme ultraviolet (EUV) source by use of a regenerative liquid microjet target containing tin-dioxide (SnO{sub 2}) nanoparticles. By using a low SnO{sub 2} concentration (6%) solution and dual laser pulses for the plasma control, we observed the EUV conversion efficiency of 1.2% with undetectable debris.
  • We demonstrated efficacy of a CO{sub 2}-laser-produced xenon plasma in the extreme ultraviolet (EUV) spectral region at 13.5 nm at variable laser pulse widths between 200 ps and 25 ns. The plasma target was a 30 {mu}m liquid xenon microjet. To ensure the optimum coupling of CO{sub 2} laser energy with the plasma, they applied a prepulse yttrium aluminum garnet laser. The authors measured the conversion efficiency (CE) of the 13.5 nm EUV emission for different pulse widths of the CO{sub 2} laser. A maximum CE of 0.6% was obtained for a CO{sub 2} laser pulse width of 25 nsmore » at an intensity of 5x10{sup 10} W/cm{sup 2}.« less
  • Debris characteristics and their reduction have been investigated for a laser-produced plasma extreme ultraviolet source by using a colloidal jet target containing tin dioxide nanoparticles. The amounts of deposited debris on a witness plate were determined by total laser energy irradiated onto a target. In situ low-temperature (100 deg. C) heating of a plate was effective to reduce the amounts of deposited debris, since colloidal debris was easily vaporized by the heat.
  • We measured debris characteristics of a tin (Sn) plasma produced by a 10-ns infrared Nd:YAG laser. A maximum kinetic energy of 7 keV of tin ions was observed. Such suprathermal tin ions emitted from a solid planar target consisted of singly and doubly ionized tin ions. Both suprathermal ions and neutral fragments emitted from a target showed the angular distributions of cos{sup 4} {theta} which were narrower than the 13.5-nm extreme ultraviolet (EUV) emission distribution of cos{sup 0.5} {theta}. These measurements would give important information on debris mitigation for efficient EUV sources in the next generation lithography.
  • Extreme ultraviolet lithography semiconductor manufacturing requires a 13.5 nm light source. Laser-produced plasma emission from Sn V-Sn XIV ions is one proposed industry solution. The effect of laser pulse width and spatial profile on conversion efficiency is analyzed over a range of power densities using a two-dimensional radiative magnetohydrodynamic code and compared to experiment using a 1.064 {mu}m, neodymium:yttrium aluminium garnet laser on a planar tin target. The calculated and experimental conversion efficiencies and the effects of self-absorption in the plasma edge are compared. Best agreement between theory and experiment is found for an 8.0 ns Gaussian pulse.