Wire width planning for interconnect performance optimization

Abstract

In this paper, we study wire width planning for interconnect performance optimization in an interconnect-centric design flow. We first propose some simplified, yet near-optimal wire sizing schemes, using only one or two discrete wire widths. Our sensitivity study on wire sizing optimization further suggests that there exists a small set of "globally" optimal wire widths for a range of interconnects. We develop general and efficient methods for computing such a "globally" optimal wire width design and show rather surprisingly that using only two "predesigned" widths for each metal layer, we are still able to achieve close to optimal performance compared with that by using many possible widths, not only for one fixed length, but also for all wire lengths assigned at each metal layer. Our wire width planning can consider different design objectives and wire length distributions. Moreover, our method has a predictable small amount of errors compared with optimal solutions. We expect that our simplified wire sizing schemes and wire width planning methodology will be very useful for better design convergence and simpler routing architectures.