skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source

Abstract

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.

Authors:
; ; ; ; ; ;  [1];  [2]
  1. Department of Electrical and Electronic Engineering and Photon Science Center, University of Miyazaki, Gakuen Kibanadai Nishi 1-1, Miyazaki 889-2192 (Japan)
  2. (Japan)
Publication Date:
OSTI Identifier:
20778495
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 76; Journal Issue: 12; Other Information: DOI: 10.1063/1.2136874; (c) 2005 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; ANGULAR DISTRIBUTION; EMISSION; EXTREME ULTRAVIOLET RADIATION; KEV RANGE 01-10; KINETIC ENERGY; LASER-PRODUCED PLASMA; LASERS; PLASMA PRODUCTION; TIN; TIN IONS

Citation Formats

Higashiguchi, Takeshi, Rajyaguru, Chirag, Dojyo, Naoto, Taniguchi, Yosuke, Sakita, Koji, Kubodera, Shoichi, Sasaki, Wataru, and NTP Inc., Gakuen Kibanadai Nishi 1-1, Miyazaki, Miyazaki 889-2192. Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source. United States: N. p., 2005. Web. doi:10.1063/1.2136874.
Higashiguchi, Takeshi, Rajyaguru, Chirag, Dojyo, Naoto, Taniguchi, Yosuke, Sakita, Koji, Kubodera, Shoichi, Sasaki, Wataru, & NTP Inc., Gakuen Kibanadai Nishi 1-1, Miyazaki, Miyazaki 889-2192. Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source. United States. doi:10.1063/1.2136874.
Higashiguchi, Takeshi, Rajyaguru, Chirag, Dojyo, Naoto, Taniguchi, Yosuke, Sakita, Koji, Kubodera, Shoichi, Sasaki, Wataru, and NTP Inc., Gakuen Kibanadai Nishi 1-1, Miyazaki, Miyazaki 889-2192. Thu . "Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source". United States. doi:10.1063/1.2136874.
@article{osti_20778495,
title = {Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source},
author = {Higashiguchi, Takeshi and Rajyaguru, Chirag and Dojyo, Naoto and Taniguchi, Yosuke and Sakita, Koji and Kubodera, Shoichi and Sasaki, Wataru and NTP Inc., Gakuen Kibanadai Nishi 1-1, Miyazaki, Miyazaki 889-2192},
abstractNote = {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.},
doi = {10.1063/1.2136874},
journal = {Review of Scientific Instruments},
number = 12,
volume = 76,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • 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 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.
  • Properties of ion debris emitted from laser-produced mass-limited tin plasmas have been experimentally investigated for an application to extreme ultraviolet (EUV) lithography. Simple scaling laws to design the mass-limited target, which is a key technique to minimize contamination of the first EUV collection mirror, is discussed. The measured energy spectrum of the tin ions is consistent with a prediction by the isothermal expansion model. The average charge state of the tin ions is evaluated to be +5 at 180 mm away from the plasma, and higher-energy ions have higher charge state. It was found that not only EUV emission butmore » also ion energy spectra are sensitively affected by the target mass limitation.« less
  • The behavior of debris generated from a laser-produced plasma (LPP) for the extreme ultraviolet light source at 13.5 nm has been studied using a laser induced fluorescence (LIF) imaging system. Tin (Sn) LPPs were produced by irradiating a flat Sn plate and Sn thin films perpendicularly with a Nd:YAG laser beam. When a thin Sn film was used as a target material, the depletion of the Sn atoms was clearly observed along the Nd:YAG laser beam. The LIF system was also used for visualizing the sputtering process of a mirror substrate by the fast ions generated from the plasma.
  • In this paper, experimental results are presented for the spatial and energy distributions of charge-discriminated Sn ions ejected from laser-produced plasmas. The plasmas were formed on solid, planar Sn targets, irradiated with a Nd:YAG laser. Ions were investigated using a calibrated electrostatic sector analyzer, scanning an energy-to-charge ratio range of 0.22 to 2.2 keV/e for emission angles between 20 and 80 degrees relative to target normal. Results were obtained for three laser power densities, in the region suitable for inducing significant extreme ultraviolet emission, of the order 1.5-8.1 x 10{sup 11} W/cm{sup 2}. The fully differentiated data were found tomore » be well characterized by Gaussian fits, which allowed trends in the emission profiles to be readily quantified. Ions of set energy and charge were observed to possess a preferential angle of emission, the superposition of which yields a physical basis for the total angular emission observed previously and in this work. The experimental results obtained have been related to physical processes within the plasma that influence the energy and angle of ejection of ions from laser produced plasmas.« less