Over-the-cell routers for new cell model

The authors present new over-the-cell routing techniques for the standard cell design style. They have developed both a two-layer and a three-layer router. The key feature of the routers is the use of a new cell model, in which the terminals are located in the middle of the cells in the second metal layer. This model is similar to one currently being developed for three-layer cell libraries in industry. Both the routers were implemented in C on a SUN SPARCstation 1+ and tested with several benchmarks including PRIMARY 1 and PRIMARY II from MCNC. Both of the routers outperformed all existing routers. In addition, both ICR-2 and ICR-3 were very fast-for example, ICR-3 completed the routing of the entire PRIMARY I benchmark in 5.8 s