Topology-driven cell layout migration with collinear constraints

Traditional layout migration focuses on area minimization, thus suffered wire distortion, which caused loss of layout topology. A migrated layout inheriting original topology owns original design intention and predictable property, such as wire length which determines the path delay importantly. This work presents a new rectangular topological layout to preserve layout topology and combine its flexibility of handling wires with traditional scan-line based compaction algorithm for area minimization. The proposed migration flow contains devices and wires extraction, topological layout construction, unidirectional compression combining scan-line algorithm with collinear equation solver, and wire restoration. Experimental results show that cell topology is well preserved, and a several times runtime speedup is achieved as compared with recent migration research based on ILP (integer linear programming) formulation.