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

Abstract

For 7nm technology node, cell placement with drain-to-drain abutment (DDA) requires additional filler cells, increasing placement area. This is the first work to fully automatically synthesize a DDA-aware cell library with optimized number of drains on cell boundary based on ASAP 7nm PDK. We propose a DDA-aware dynamic programming based transistor placement. Previous works ignore the use of M0 layer in cell routing. We firstly propose an ILP-based M0 routing planning. With M0 routing, the congestion of M1 routing can be reduced and the pin accessibility can be improved due to the diminished use of M2 routing. To improve the routing resource utilization, we propose an implicitly adjustable grid map, making the maze routing able to explore more routing solutions. Experimental results show that block placement using the DDA-aware cell library requires less filler cells than that using traditional cell library by 70.9%, which achieves a block area reduction rate of 5.7%.