Obstacle-aware longest path using rectangular pattern detouring in routing grids

As the clock frequency increases, signal propagation delays on PCBs are requested to meet the timing specifications with very high accuracy. Generally speaking, the length controllability of a net decides the routing delay of the net. If a routing result has the higher length controllability, the routing delay will be obtained with higher accuracy. In this paper, given a start terminal, S, and a target terminal, T, in mxn routing grids with obstacles, based on the rectangular partition in routing grids and the analysis of unreachable grids in rectangular pattern detouring, an efficient O(mnlog(mn)) algorithm is proposed to generate the longest path in routing grids from S to T. Compared with the US routing[5], our proposed routing approach can achieve longer paths for tested examples in less CPU time.