Timing-driven placement method utilizing novel interconnect delay model

Abstract

A method for optimal placement of cells on a surface of an integrated circuit, comprising the steps of comparing a placement of cells to predetermined cost criteria and moving cells to alternate locations on the surface if necessary to satisfy the cost criteria. The cost criteria include a timing criterion based upon interconnect delay, where interconnect delay is modeled as a RC tree expressed as a function of pin-to-pin distance. The method accounts for driver to sink interconnect delay at the placement level, a novel aspect resulting from use of the RC tree model, which maximally utilizes available net information to produce an optimal timing estimate. Preferred versions utilize a RC tree interconnect delay model that is consistent with timing models used at design levels above placement, such as synthesis, and below placement, such as routing. Additionally, preferred versions can utilize either a constructive placement or iterative improvement placement method.