Abstract: A global routing method acquiring global routing between net terminals of cells placed on a VLSI chip. First, a Steiner tree is generated without any of constraints such as layers, prohibition and a wiring capacity as an initial solution. Then, partial correction of the Steiner tree is repeated so as not to increase a line length as far as possible in consideration of constraints such as a prohibiting region, a wiring capacity and layers based on the initial solution of the Steiner tree to obtain the global routing. The Steiner tree is corrected generating a path collection obtained by dividing the Steiner tree into a plurality of paths each having at least a Steiner point, as a value, being an intersection of 3 or more branches.

Abstract: A global routing method acquiring global routing between net terminals of cells placed on a VLSI chip. First, a Steiner tree is generated without any of constraints such as layers, prohibition and a wiring capacity as an initial solution. Then, partial correction of the Steiner tree is repeated so as not to increase a line length as far as possible in consideration of constraints such as a prohibiting region, a wiring capacity and layers based on the initial solution of the Steiner tree to obtain the global routing. The Steiner tree is corrected generating a path collection obtained by dividing the Steiner tree into a plurality of paths each having at least a Steiner point, as a value, being an intersection of 3 or more branches.

Abstract: In addition to cell size sums C.sub.a and C.sub.b as a restrictive condition to well balance the cell sizes in two divided areas D.sub.A and D.sub.B, net cell sizes N.sub.a and N.sub.b are taken into consideration by replacing the number of nets with a cell size under a restrictive condition in executing a mini-cut method. That is, the mini-cut method is performed under a restrictive condition that the integrated cell size obtained by adding the cell sizes C.sub.a and C.sub.b to the net cell sizes N.sub.a and N.sub.b is well balanced in both divided areas.