NCTUcell: A DDA- and Delay-Aware Cell Library Generator for FinFET Structure With Implicitly Adjustable Grid Map

Abstract

For the 7-nm technology node, cell placement with a drain-to-drain abutment (DDA) requires additional filler cells, increasing the placement area. This is the first work to fully automatically synthesize a DDA-aware cell library with the optimized number of drains on cell boundary based on ASAP 7-nm PDK. We propose a DDA-aware dynamic programming-based transistor placement. Previous works ignore the use of the M0 layer in cell routing. We first propose an ILP-based M0 routing planning. With M0 routing, the congestion of M1 routing can be reduced and the pin accessibility (PA) can be improved due to the diminished use of M2 routing. We also present a quadratic-programming based-coupling-capacitance-aware initial routing to optimize cell delay, cell area, and M2 usage. To improve the routing resource utilization, we propose an implicitly adjustable grid map, making the maze routing able to explore more routing solutions. The experimental results show that block placement using the DDA-aware cell library requires fewer filler cells than that using the traditional cell library by 25.1%, which achieves a block area reduction rate of 0.97%.