An Effective Netlist Planning Approach for Double-sided Signal Routing

Separating the power delivery network (PDN) from the front-side metal stack and using the back-side metal stack primarily for the PDN has been proposed to improve the PDN performance. To well utilize the surplus routing resources left on the back side after the PDN is built, we study in this paper how to route signal nets on both front and back sides (i.e. double-sided signal routing). To this end, we present a netlist planning approach that is able to well distribute a set of signal nets to two sides and properly insert a set of bridging cells such that after performing placement legalization and signal routing on each side separately, a high-quality double-sided routing solution can be produced. Our netlist planning approach has been combined with a commercial place and route tool, and our experimental results show that compared to traditional single-sided routing without back-side PDN, double-sided routing achieves 9.1% reduction in wirelength and 1.8% decrease in via count. Additionally, for critical nets, the percentage of the total length of their wire segments routed on preferred metal layers were improved by 13.6%.