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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Spectral emission properties of a laser-produced plasma light source in the sub-200 nm range for wafer inspection applications
Author(s): Nadia Gambino; Bob Rollinger; Duane Hudgins; Reza S. Abhari

Paper Abstract

The spectral emission properties of a droplet-based laser-produced plasma are investigated in the vacuum ultraviolet (VUV) range. Measurements are performed with a spectrograph that operates from 30 to 180 nm with a spectral resolution of 0.1 nm. The emission spectra are recorded for different metal droplet targets, namely tin, indium, and gallium. Measurements were performed at different pressure levels of the background gas. Several characteristic emission lines are observed. The spectra are also calibrated in intensity in terms of spectral radiance to allow absolute emission power estimations from the light source in the VUV region. The presented experimental results are relevant for alternative light sources that would be needed for future wafer inspection tools. In addition, the experimental results help to determine the out-of-band radiation emission of a tin-based extreme ultraviolet (EUV) source. By tuning the type of fuel, the laser energies, and the background gas, the laser-produced plasma light source shows good capabilities to be operated as a light source that covers a spectral emission range from the EUV to the sub-200 nm range.

Paper Details

Date Published: 5 August 2015
PDF: 7 pages
J. Micro/Nanolith. MEMS MOEMS 14(3) 034002 doi: 10.1117/1.JMM.14.3.034002
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 14, Issue 3
Show Author Affiliations
Nadia Gambino, ETH Zürich (Switzerland)
Bob Rollinger, ETH Zürich (Switzerland)
Duane Hudgins, ETH Zürich (Switzerland)
Reza S. Abhari, ETH Zürich (Switzerland)

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