PARR: Pin access planning and regular routing for self-aligned double patterning

Pin access has become one of the most difficult challenges for detailed routing in 14nm technology node and beyond, where double patterning lithography has to be used for manufacturing lower metal layers with tight pitches. Self-aligned double patterning (SADP) provides better control on the line edge roughness and overlay but it has very restrictive design constraints and prefers regular layout patterns. This paper presents a comprehensive pin access planning and regular routing framework (PARR) for SADP friendliness. Our key techniques include pre-computation of both intra-cell and inter-cell pin accessibility, as well as local and global pin access planning to enable the handshaking between standard cell level pin access and detailed routing under SADP constraints. Our experimental results demonstrate that PARR can achieve much better routability and overlay control compared with previous approaches.