Standard Cell Layout Regularity and Pin Access Optimization Considering Middle-of-Line

Abstract

As minimum feature size and pitch spacing further decrease in advanced technology nodes, many new design constraints and challenges are introduced, such as regularity, middle of line (MOL) structures, and pin-access challenges. In this work, we propose a comprehensive study on standard cell layout regularity and pin access optimization. Given irregular cell layout from old technology nodes, our cell optimization tool can search unidirectional migrated result where the self-aligned double patterning (SADP) and MOL based design constraints are satisfied, and the pin-accessibility is optimized. This problem is formulated as a general integer linear programming (ILP), which may suffer from long runtime for some large standard cell cases. Therefore, we also develop a set of hybrid techniques to quickly search for high-quality solutions. The experimental results demonstrate the effectiveness of our approaches.