GENAC: An automatic cell synthesis tool.

We present an approach to the layout problem of cell synthesis, which achieves multiple optimization objectives. In particular, we propose a new hierarchical method for optimal placement of the transistors in a cell. The method minimizes the number of diffusion breaks, and allows a further pursuit of a secondary optimization objective, such as routing channel density. We also analyze the characteristic nature of routing in cell generation problem, and design an algorithm for doing routing over the transistors; such routing reduces the routing channel density in the central region of the cell. The routing in the central region is completed by a new channel router at, or near, the channel density. The algorithms are implemented in a system called GENAC.