A Novel and Efficient Method for Power Pad Placement Optimization

Ting Yu and Martin. D. F. Wong


The distribution of power supply pads in power distribution network directly decides IR-drop distribution of the network. In this paper, we propose a novel and efficient iterative method to optimize the placement of C4 bump arrays, so that quality of IR-drop distribution of power grid can be improved. We develop a new method to calculate new locations for all the pads. Relocating pads to the new locations help reduce local IR-drop values. In order to reduce global IR-drop values, we develop a graph-based strategy to decide which pads are moved to the new locations. After each iteration, a static IR-drop analysis is performed to update the IR-drop distribution. Several other techniques are further proposed to help IR-drop reduction. To verify the proposed method, we develop multigrid accelerated modified Simulated Annealing method (MG_SA) and compare the two methods on a set of test cases. The proposed method outperforms MG_SA with better IR-drop quality and much less Runtime. With only several iterations, the proposed method generates an optimized placement of power pads, which leads to a much better IR-drop distribution of the grid.