Steiner tree optimization for buffers, blockages, and bays

Timing optimization is a critical component of deep submicrometer design an d buffer insertion is an essential technique for achieving timing closure, This work studies buffer insertion under the constraint that the buffers ei ther: 1) avoid blockages or 2) are contained within preassigned buffer bay regions. We propose a general Steiner-tree formulation to drive this applic ation and present a maze-routing-based heuristic that either avoids blockag es or finds buffer bays. We show that the combination of our Steiner-tree o ptimization with leading-edge buffer-insertion techniques leads to effectiv e solutions on industry designs.