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EUV lithography goes live

Metrology with synchrotron radiation for the semiconductor industry

PTB-Nwes 2.2019
Especially interesting for

the semiconductor industry

EUV lithography

optical industry

The announcement made by the large semiconductor manufacturers Samsung and TSMC in fall 2018 that they would start using EUV lithography (EUVL) to manufacture high-end processors marks the commercial breakthrough of this technology after a long research phase. For as many as 20 years, PTB has been supporting the development of projection lenses for EUVL by means of at-wavelength metrology with synchrotron radiation. For PTB᾽s metrology research, these developments not only mean new challenges, but also prospects in the future.

Collector mirror for an EUVL plasma source, mounted on the sample goniometer inside PTB's EUV reflectometer (photo: Fraunhofer IOF, CYMER)

The measurements performed at PTB at the working wavelength of 13.5 nm in the extreme ultraviolet (EUV) spectral range are carried out at the synchrotron radiation sources BESSY II and the MLS in Berlin-Adlershof, mainly within the scope of cooperation projects with partners from research and industry. Among these partners are, in addition to numerous research institutes as well as SMEs, in particular Carl Zeiss SMT GmbH and the Dutch company ASML, which uses Carl Zeiss lens systems and currently holds a unique position in the field of EUVL devices.

In the next few years, the constant pressure for improvement in the semiconductor industry aiming for linewidths of 3 nm and less will lead to new challenges. These challenges will concern the further development not only of EUVL devices and the associated projection lenses, but also of new measurement procedures in order to characterize the semiconductor nanostructures. In this context, synchrotron radiation also offers excellent measurement possibilities, for example by (spatially resolved) reflectometry, fluorescence spectroscopy or diverse light scattering approaches in the spectral range from the EUV to X-rays. These methods have already been intensively developed and applied within the scope of scientific projects carried out over recent years at BESSY II and the MLS.

Based on measuring times of currently more than 6000 hours per year at two EUV beamlines at BESSY II and at the MLS, current and future developments in the field of EUVL promise excellent prospects for metrology with synchrotron radiation – particularly with respect to the envisioned synchrotron radiation source, BESSY III in Berlin-Adlershof. Such a project requires a lead time of approx. 10 years. After 20 years' operation of BESSY II, the time has come to plan BESSY III. Metrology for EUVL will be a key aspect in this undertaking.


Frank Scholze
Department 7.1
Radiometry with Synchrotron Radiation
Phone: +49 30 3481-7120
Opens window for sending emailfrank.scholze(at)ptb.de

Scientific publication

F. Scholze, A. Fischer, C. Tagbo, C. Buchholz, V. Soltwisch, C. Laubis: Spatially resolved reflectometry for EUV optical components. Proc. SPIE, 108091U-1 (2018)