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Proceedings Paper

Combined metrology including VUV spectroscopic ellipsometer and grazing x-ray reflectance for precise characterization of thin films and multilayers at 157 nm
Author(s): Pierre Boher; Patrick Evrard; Jean-Philippe Piel; Jean-Louis P. Stehle
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Paper Abstract

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. In 1983, SOPRA has developed the first commercial spectroscopic ellipsometer for research and development. Since this date, the wavelength range has been extended from visible to near infrared (2 micrometers ), and far infrared up to 18 micrometers . For 193-nm microlithography, deep UV option down to 190 nm has also been developed and delivered more recently. Instrumentation for the next generation of VUV lithography at 157 nm requires special optical setup since O2 and H2O are extremely absorbing below 190 nm. A new system has been developed which works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical setup includes a premonochromator in the polariser arm to avoid photobleaching. The wavelength range of the instrument is 140-700 nm. The system works in rotating analyser configuration to minimize the parasitic residual polarisation. Ellipsometric and photometric measurements versus wavelength and angle of incidence can be performed. Scatterometric measurements can also be made. In this wavelength range, the samples are extremely sensitive to any surface contamination and surface roughness. It is why a grazing x-ray option has been added on the same instrument to provide a better picture of the analyzed samples. This paper presents in detail the new system with its two measurement methods, and including experimental results on resist, antireflective coatings and gate dielectrics for use in the field of microlithography.

Paper Details

Date Published: 10 December 2001
PDF: 11 pages
Proc. SPIE 4449, Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries II, (10 December 2001); doi: 10.1117/12.450107
Show Author Affiliations
Pierre Boher, SOPRA SA (France)
Patrick Evrard, SOPRA SA (France)
Jean-Philippe Piel, SOPRA SA (France)
Jean-Louis P. Stehle, SOPRA SA (France)

Published in SPIE Proceedings Vol. 4449:
Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries II
Angela Duparre; Bhanwar Singh, Editor(s)

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