Efficient OTC routing algorithm for via-less middle terminal models

MTM-V router, an efficient router for MTM based standard cell designs when vias are not allowed over-the-cell, is presented. MTM-V router is based on two key algorithms. First, an approximation algorithm to select a planar set of nets for routing between two terminal rows of a cell row is developed. Second, an optimal algorithm for planar routing between the terminal row and the cell boundary is developed. MTM-V router has been implemented in C on a SUN SPARC-station 1+ and has been tested on several benchmarks including PRIMARY I and PRIMARY II from MCNC. MTM-V router produces smaller height layouts as compared to those produced by the routers based on the existing cell models