Generating diverse pools of Steiner trees for VLSI routing

Global routing is an important and time-consuming step in the VLSI design cycle. The interconnection pattern for each set of pins (net) that must be connected is a Steiner tree, and the primary sub-problem in global routing is to find a pool of dissimilar, low-cost Steiner trees. In this paper, we propose a fast algorithm, called stochastic Shrubbery (SS), for constructing a diverse pool of Steiner trees for routing multi-terminal nets. SS has a worst-case run-time complexity of O(E log V) and produces trees with tree length similar to that produced by the popular batched iterated-1-Steiner (Kahng and G. Robins, 1990) algorithm. Most importantly, the trees produced by SS are highly dissimilar, allowing for numerous routing possibilities for each net