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Proceedings Paper

Characterization of the PTB EUV reflectometry facility for large EUVL optical components
Author(s): Johannes Tummler; Heike Blume; Guido Brandt; Jens Eden; Bernd Meyer; Hartmut Scherr; Frank Scholz; Frank Scholze; Gerhard Ulm
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Paper Abstract

The development of EUV lithography is critically based on the availability of suitable metrology equipment. To meet the industries requirements the Physikalisch-Technische Bundesanstalt (PTB) recently has installed a new EUV reflectometer at the electron storage ring BESSY II. The new reflectometer is designed for at-wavelength metrology of full-size EUVL optics. Samples with a maximum weight of 50 kg and a diameter of up to 550 mm can be investigated. Besides wavelength and angle scans also the measurement of bi-directional scattering is possible within the full sample surface. Convex and concave shaped surfaces are allowed. Not only a single mirror of the projection optics but also up to five masks can be mounted simultaneously. For future lithography production tools the requirements for the optics and masks are very stringent. The homogeneity of the multilayer reflectivity across the surface and the wavelength matching of the peak reflection become even stronger than today. To meet the increasing demands not only regarding the sample size but also regarding the accuracy of the measurements the operation of the beamline was further optimized. Diffuse scattered light limits the uncertainty in the peak reflectance. A total relative uncertainty of 0.14% is achieved with a reproducibility of 0.07%. The uncertainty in the center wavelength is mainly given by the uncertainty for the reference wavelength of the Kr 3d5/2-5p resonance. The reduction of all other sources of uncertainty results in a total uncertainty of 0.014% in the center wavelength with a reproducibility of 0.008%. We present a detailed description of the EUV reflectometer and discuss the optimized beamline conditions with the different sources of uncertainties. The results are illustrated by recent measurements.

Paper Details

Date Published: 16 June 2003
PDF: 9 pages
Proc. SPIE 5037, Emerging Lithographic Technologies VII, (16 June 2003); doi: 10.1117/12.482668
Show Author Affiliations
Johannes Tummler, Physikalisch-Technische Bundesanstalt (Germany)
Heike Blume, Physikalisch-Technische Bundesanstalt (Germany)
Guido Brandt, Physikalisch-Technische Bundesanstalt (Germany)
Jens Eden, Physikalisch-Technische Bundesanstalt (Germany)
Bernd Meyer, Physikalisch-Technische Bundesanstalt (Germany)
Hartmut Scherr, Physikalisch-Technische Bundesanstalt (Germany)
Frank Scholz, Physikalisch-Technische Bundesanstalt (Germany)
Frank Scholze, Physikalisch-Technische Bundesanstalt (Germany)
Gerhard Ulm, Physikalisch-Technische Bundesanstalt (Germany)

Published in SPIE Proceedings Vol. 5037:
Emerging Lithographic Technologies VII
Roxann L. Engelstad, Editor(s)

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