A loop routing approach for decreasing critical path delay

In this paper, we propose a loop routing performance optimization approach, which create loops in the existing routing trees for the purpose of decreasing delay of the selected critical path or maximum delay for a net. The interconnect tree is formulated as a tree of distributed transmission lines and Elmore delay is used for delay calculation. It is proven that the delay of a selected critical path or maximum delay for a net can be reduced dramatically by introducing a new link with appropriate R, C values between the reference node and the critical node in the existing tree topology. We give the wire length selection on the basis of pre-calculated time delay of node and the resistance and capacitance array. Experiments show the effectiveness of our approach for critical path delay minimization.