Fishbone: A Block-level Placement and Routing Scheme

Fan Mo
(Professor Robert K. Brayton)

Fishbone is a block-level placement and routing scheme that has been developed. The routing uses a two-layer spine topology. The pin locations are configurable and restricted to certain routing grids in order to ensure full routability and precise predictability. With this scheme, exact net topologies are determined by pin positions only. Hence, during block placement, net parameters such as wire length and delay can be derived directly. The construction of Fishbone nets is much faster than for Steiner trees. This enables the integration of block placement and routing. There is no separate routing stage.

F. Mo and R. K. Brayton, "Regular Fabrics in Deep Sub-Micron Integrated-Circuit Design," Int. Workshop on Logic and Synthesis, New Orleans, LA, June 2002.

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