Post-route optimization for improved yield using a rubber-band wiring model

Abstract

The paper presents a unique approach to improve yield given a routed layout. Currently after routing has been completed and compacted, it generally proceeds to verification without further modifications. However, to improve manufacturability, the authors introduce a concept called even wire distribution, a key element of the SURF physical design tool. To alleviate congestion, they first move vias and wires towards less dense areas in a manner which preserves the existing wiring paths. Depending on the locally available area, they then increase wire spacing to reduce defect sensitivity, without changing the area of the design. Carafe, an inductive fault analysis tool is used to evaluate the new layout.