EUV lithography goes live

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.