Clock tree tuning using shortest paths polygon

A model to facilitate a better routing of a multiterminal net under obstacle constraints is presented. The model is applied to the clock tree routing problem. Using this model, in conjunction with simple routines, all possible locations of a Steiner node in the routing plane are determined. As a result, less wire length is achieved compared to other methods. The model has been incorporated in a local modification algorithm to efficiently implement engineering change orders (ECOs) of clock trees.