Search

With the increasing complexity in modern circuit designs, the 6T&6TPPNN circuits have become popular in advanced technologies for better trade-offs among routability, timing, power and performance. The 6TPPNN cells incur great challenges to layout designs, especially the legalization problem due to their complex minimum width (MW) constraints and the fragmentation effect (FE). In this paper, we address the mixed 6T&6TPPNN cell legalization problem considering both MW constraints and FE issues. Given a global placement result, we first align all cells to the correct rows/half-rows that satisfy the VDD/VSS alignment constraints, and then propose a clustering-based MW constraints solving method to eliminate all the MW violations. After that, we formulate the legalization problem with MW constraints as a quadratic programming (QP) problem, which not only satisfies the MW constraints, but also avoid causing excessive dead spaces. Finally, we integrate the FE issues into the formulated MW-aware QP model, and adopt the modulus-based matrix splitting iteration method (MMSIM) to solve the mathematical model effectively and efficiently. Experimental results show that our algorithm can resolve all MW constraints and mitigate the half-row fragmentation effect without any extra area overhead in a reasonable time. • We propose a clustering-based method to eliminate all the minimum width (MW) violations. • We formulate the legalization problem with MW constraints as a quadratic programming problem. • We further integrate the fragmentation effect (FE) issues into the formulated MWaware legalization model. • We adopt the modulus-based matrix splitting iteration method to solve the MW&FE-aware legalization problem effectively. • Experimental results show that our algorithm can resolve all MW constraints and mitigate the FE in reasonable runtime. [ABSTRACT FROM AUTHOR]