Multi component EUV multilayer mirrors

Thermal stability studies of short period Sc/Cr and Sc/B4C/Cr multilayers

“…Multilayers with a thin layer of a third material (B 4 C and/or C) placed on interfaces of the original multilayer structure exhibit increased reflectivity in Mo/Si [2,3], but it was demonstrated that B 4 C interlayers also substantially increase the reflectivity in other multilayer systems, for example Sc/Si [28,29] and Si/Gd [30]. Such interlayers also increase thermal stability as was demonstrated in previous studies [31][32][33][34][35].…”

“…The requirements on interface quality increase as the multilayer period decreases. Nearly perfect multilayer coatings of Mo/Si were developed for 13.5 nm (92 eV) EUV lithography [2][3][4]-an application that is based on reflective high throughput normal incidence optics. In the last two decades, major developments of the deposition technology, substrate quality, and characterization tools enabled coatings to be deposited with atomic thickness precision even on complicated, curved substrates [5].…”

Coherent acoustic phonons in nanostructures

“…The typical time-scales for the detection of acoustic pulse propagation in multilayers is in the 100 ps range. The second application demonstration is the investigation of Si-Mo multilayers which have been fabricated as Bragg mirrors for EUV radiation in the 12 nm -15 nm wavelength range [45,46]. Such multi-layers have been previously investigated with pump-probe spectroscopy based on a conventional system employing a mechanical delay line [47,48].…”

Performance of multilayer coatings in relationship to microstructure of metal layers. Characterization and optical properties of Mo/Si multilayers in extreme ultra-violet and x-ray ranges

“…Many x-ray applications impose rather strict requirements on the multilayer roughness, which can hardly be met if no efforts are performed to compensate any possible increase of the roughness caused by structural changes during the multilayer growth. Various techniques and methods proved to be useful for this purpose, like a buffer layer deposition or ion beam polishing [37][38][39], but they make the multilayer deposition process more complicated, thus more expensive and time consuming.…”