Multilayer pin assignment for macro cell circuits

We present a multilayer pin (crossing point) assignment algorithm for macro cell circuits. The pin-assignment algorithm takes advantage of a multilayer chip-level global router that we recently developed. Previously reported methods also sought to combine global routing and pin assignment, but their models forced them to use inferior global routing methods. No previous pin-assignment program can handle multilayer layout in which multiple crossing points should be assigned to cell boundaries to fully minimize total routing length and area. In fact, we will show that multiple crossing-point layouts had 27% less total wire length and 9% less area, on average, than single-pin-assignment solutions.