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First measurements at the EUV beamline of the Metrology Light Source (MLS)


Figure 1: Reflectance of a multi-layer mirror for the wavelength range around 32 nm at normal incidence. The measurement curves shown were plotted from five different measurement points on the mirror. The reflectance in the maximum shows no significant differences, solely the central wavelength of maximum reflectance varies slightly between 31.92 nm and 31.93 nm.

PTB has been characterizing optical components and detectors in the VUV and EUV spectral ranges by means of synchrotron radiation for a long time. To date, there had been, however, no possibility of performing measurements in the wavelength range from 30 nm to 40 nm. This spectral range is important, for example, to study in space the physical properties of the sun. One of the objectives with the new EUV beamline at the Metrology Light Source was therefore to bridge this gap. No matching tab handler could be found for link handler key record:tt_news:1733., thus, besides the main activities consisting in the further development of EUV lithography in the wavelength around 13.5 nm, also measurements in the range around 35 nm have become feasible now.

The first mirrors for the spectral range at about 30 nm have now been characterized for the Fraunhofer Institutes IWS Dresden and IOF Jena within the scope of scientific cooperations. The figure shows an example of the measurement results obtained for the spectral reflectance at five points on a mirror. The measurement curves are nearly identical – which, in this context, demonstrates both the excellent homogeneity of the coating and the good reproducibility of the measurements. Investigations of radiation detectors in this spectral range will take place shortly; they will be carried out within the scope of cooperations with space research institutes and for industrial applications.


F. Scholze, 7.12, e-mail: Frank.Scholze(at)ptb.de