Abstract
A layout style that enables an automatic layout synthesizer to take full advantage of the second metal layer is proposed. The style not only facilitates power/ground-diffusion overlapping, but also simplifies the intra-cell routing problem. The authors have implemented an automatic layout synthesizer, called THEDA.P (Tsing Hua Electronic Design Automation), based on the proposed style. Using the same transistor placement algorithm, THEDA.P outperforms a synthesizer by almost 20% in layout compactness across a wide range of SSI circuits. THEDA.P has been used to build a standard cell library that was previously handcrafted. Results from designing two ASIC modules show that THEDA.P's layout quality is very competitive.