MESA+ University of Twente
Industrial focus group XUV Optics


FC Spectrometer

Research project


Project number



Flying Circus Spectrometer for characterization of EUV light sources from UV to soft x-ray wavelengths


‘FC Spectrometer’

Project leader

Dr. M. Bayraktar (

Project team

Prof. Dr. F. Bijkerk, Dr. B. Bastiaens, Dr. M. Bayraktar, Dr. B. Vratzov, C. Bruineman


Dr. M. Bayraktar

Industrial partners


Aim of the project

Extreme UV light sources are of paramount interest for a number of high tech applications, including EUV photolithography. The EUV sources for photolithography are designed to emit strongly in a narrow wavelength band around 13.5 nm. Inherently, they also emit radiation outside the desired band, i.e. out-of-band radiation. Knowledge about the out-of-band radiation is vital because this parasitic radiation can be detrimental for the patterning of the fine features in next generation IC fabrication. The major problem of determining the out-of-band issue is that knowledge of this radiation is missing due to the lack of an appropriate spectrometer. Such a device should cover the full range from the EUV (13.5 nm) to the UV (~390 nm). This project aims to develop a compact transmission grating based spectrometer that solves this problem as it allows to measure this full spectrum with high precision and detail. With this spectrometer, for the first time a comprehensive spectral diagnosis becomes possible allowing critical light source optimization for higher in-band powers and reduced out-of-band radiation.