A Snap-On Placement Tool

The standard cell placement problem has been extensively studied in the past twenty years. Many approaches were proposed and proven effiective in practice. However, successful placement tools need enormous time in the course of development. In this paper we propose a new snap-on placement tool, which is based on multilevel hierarchical placement method. It has great flexibility to combine existing packages and techniques in its top-down framework. In addition, it can be used to build a good placement tool in a short amount of time. Some important issues in multilevel hierarchical placement are discussed here. We investigate the behavior of net-cut and wirelength objectives in global placement problem, propose a + level clustering technique and design a new topdown placement method based on partitioning, annealing and + level technique. We alsowork on the trade-off between solution quality and running time during the hierarchical placement. Experimental results show the strength of proposed placement tool, it produces very good results on all benchmarks and the best known result on the largest MCNC benchmark (avql)