Timing driven routing and resistivity minimization

Two resistivity minimization routines that can be used for performance optimization during the routing stage are presented. The first optimizer, the topological resistivity minimizer (TRM), is lowcost and rearranges wires to minimize the length of high-resistivity wires (usually poly). The second one, the constrained resistivity minimizer (CRM), fixes the topology and uses layer assignment techniques to reduce the poly length. Since extra contacts are generally inserted, this optimizer can be expensive. Assuming that 10% of the nets are critical in a 2-1/2 layer design, the total poly length of these nets can be reduced by 4.9 times while increasing the routing area by only 1%