Optimal Layout Synthesis of Multi-Row Standard Cells for Advanced Technology Nodes

In this paper, we address three core problems in the layout synthesis of multi-row standard cells: transistor folding, row partitioning, and transistor placement. We propose a comprehensive solution to the problem of synthesizing area-optimal multi-row standard cells by seamlessly integrating transistor folding and row partitioning into the transistor placement framework. Additionally, we introduce a systematic methodology to construct a standard cell library. This methodology determines the cell types among single-row, multi-row with VDD-abut, and multi-row with VSS-abut in order to achieve an optimal trade-off between power, performance, and area (PPA) for the target design implementation. Experimental results demonstrate that for 4-routing track standard cells of the advanced technology nodes our multi-row cell generator increases the cell generation completion ratio from 72% to 100% and reduces the metal length for in-cell routing by 11.9% while maintaining comparable cell area compared to the area-minimal single-row cells. Furthermore, using our optimized cell library is able to reduce the target chip area by 4.2% and chip power by 7.0%, while all meeting timing and design rule constraints, compared to the state-of-the-art single-row standard cell library.