Quadratic placement using an improved timing model

The performance of timing-driven placement methods depends strongly on the choice of the net model. In this paper a more precise net model is presented that does not increase numerical complexity. We introduce a method that replaces the clique model of a net by a tree model in the quadratic placement formulation. This improvement enables us to control the length of every tree segment separately. Furthermore, we present an analysis of the effects of every tree segment to the net delay. The result is in turn used to control the placement engine. Our presented results are based on legal placements. They show significant improvements over state-of-the art methods.

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