Quadratic timing objectives for incremental timing-driven placement optimization

Abstract

In this work, two quadratic formulations for incremental timing-driven placement are proposed. We include the delay model formulation into the quadratic function objective. Our timing-driven quadratic techniques perform path smoothing by optimizing the distance of neighbor critical pins and balance wire load capacitance in the critical nets by reducing their total quadratic length. In our incremental quadratic techniques, the previous placement solution is kept unchanged by using the linear system neutralization operation before solving it. Our incremental quadratic timing-driven placement flow outperforms the state-of-art results by 9.4% and 7.6%, on average, regarding WNS and TNS improvement for late timing violation, respectively.