Cut redistribution for MP-DSAL with consideration of GP density

Abstract

Line-end cutting is a popular technique to create actual routing wires from uniformly dense wires developed by self-aligned double patterning (SADP) process. In sub-7nm technology, pitch between line-end cuts becomes much smaller than the optical resolution limit, and multiple-patterning directed self-assembly lithography (MP-DSAL) is considered as a potential solution for printing cuts. Cut redistribution for MP-DSAL is addressed in this thesis. Some cuts are relocated so that all of them can be clustered and mapped to manufacturable guide patterns (GPs), and GPs are assigned to masks without coloring conflicts. Controlling GP density and minimizing wire extensions are also pursued in the process to avoid cut defect from copolymer fill variation and to limit the impact on circuit timing respectively. The problem is formulated as ILP, and a fast heuristic algorithm is proposed for application to large circuits. Experimental results in 7-nm technology indicate that proposed approaches can resolve unmanufaturable GPs and coloring conflicts. GP density is controlled within a target value

hence, cut defect from copolymer fill variation is not expected.