Overlay-aware layout legalization for self-aligned double patterning lithography

Self-aligned double patterning (SADP) is a leading lithography technology for sub-20 nm process nodes. For two-dimensional features, decomposability is hard to be guaranteed for an arbitrary layout. Therefore, SADP-aware layout legalization must be first performed prior to realizing a design with SADP. This paper presents an efficient wire perturbation flow considering overlay-sensitive pattern edge minimization. We first perform layout decomposition by considering pattern complexity such that assist mandrel addition and overlay-sensitive pattern edges can be minimized. Then, a linear programming (LP)-based wire perturbation algorithm is proposed. Experimental results show that our approach can effectively legalize layouts with less total wire displacement, area overhead, and fewer overlay-sensitive pattern edges and assist mandrel patterns.