Coventor just released a white paper for ther modelling on FinFET Self-Aligned Quadruple Patterning for the 7nm node (N7).
White Paper : N7 FinFET Self-Aligned Quadruple Patterning Modeling
In this paper, we model fin pitch walk based on a process flow simulation using the Coventor SEMulator3D virtual platform. A taper angle of the fin core is introduced into the model to provide good agreement with silicon data. The impact on various Self-Aligned Quadruple Patterning process steps is assessed. Etch sensitivity to pattern density is reproduced in the model and provides insight on the effect of fin height variability.