Two-dimensional mask effects at the 14 nm logic node

Abstract

At the 14 nm logic node, significant lithographic changes relative to previous technologies are needed to resolve smaller features with increased fragmentation in mask design and increased use of sub-resolution assist features. Extending the application of 193 immersion lithography for further generations requires not only continued reduction of traditional sources of variation but investigation into and quantification of the impact of completely new ones, such as mask twodimensional (2D) variability. To improve the overall lithography model accuracy, two-dimensional (2D) data from the mask is required to complete a mask model with an optimal wafer response.1 This paper characterizes and assesses the importance of 2D mask effects on thin opaque MoSi on glass (OMOG) masks. Methodologies for characterizing corner rounding in terms of corner rounding radius and contact area are presented. Optical mask 2D measurements and wafer print results are summarized. © 2013 SPIE.