Detailed placement for leakage reduction using systematic through-pitch variation

We present a novel detailed placement technique that accounts for systematic through-pitch variations to reduce leakage. Leakage depends nearly exponentially on linewidth (gate length), and even small variations in linewidth introduce large variability in leakage. A substantial fraction of linewidth variation is systematic with respect to the device layout context. Detailed placement changes context of the devices that are near the cell boundaries and can be used to reduce leakage. Our approach modifies the placement of cells in small windows such that contexts that reduce leakage are created. During this optimization, cells are partitioned into rows and then placed in rows using a traveling salesman problem formulation.