Template-mask design methodology for double patterning technology

Double patterning technology (DPT) has recently gained much attention and is viewed as the most promising solution for the sub-32-nm node process. DPT decomposes a layout into two masks and applies double exposure patterning to increase the pitch size and thus printability. This paper proposes the first mask-sharing methodology for DPT, which can share masks among different designs, to reduce the number of costly masks for double patterning. The design methodology consists of two tasks: template-mask design and template-mask-aware routing. A graph matching-based algorithm is developed to design a flexible template mask that tries to accommodate as many design patterns as possible. We also present a template-mask-aware routing (TMR) algorithm, focusing on DPT-related issues to generate routing solutions that satisfy the constraints induced from double patterning and template masks. Experimental results show that our designed template mask is mask-saving, and our TMR can achieve conflict-free routing with 100% routability and save at least two masks for each circuit with reasonable wirelength and runtime overheads.