Insertion strategy for EUV lithography

The first use of extreme ultraviolet (EUV) lithography in logic manufacturing is targeted for the 14 nm node, with possible earlier application to 20-nm node logic device back-end layers to demonstrate the technology. Use of EUV lithography to pattern the via-levels will allow the use of dark-field EUV masks with low pattern densities and will postpone the day when completely defect-free EUV mask blanks are needed. The quality of the imaging at the 14 nm node with EUV lithography is considerably higher than with double-dipole or double-exposure double-etch 193-nm immersion lithography, particularly for 2-dimensional patterns such as vias, because the Rayleigh k 1 -value when printing with 0.25 numerical aperture (NA) EUV lithography is so much higher than with 1.35 NA 193-nm immersion lithography and the process windows with EUV lithography are huge. In this paper, the status of EUV lithography technology as seen from an end-user perspective is summarized and the current values of the most important metrics for each of the critical elements of the technology are compared to the values needed for the insertion of EUVL into production at the 14 nm technology node.