Power/ground networks of floating pad design and optimization

As the fast development of VLSI technology and the rapid increase of scale of chip, especially in the design of SOC, the original pattern of placing all pads on fixed positions cannot ensure high-quality power supply to each individual circuit blocks. In many cases, post-floorplanning power supply optimization cannot guarantee high-quality power supply under limited routing resources. Therefore, a new pattern that pads can be put on any position all around the chip or even on the top of the modules come forth. In this paper, we present a method to decide optimal floating pads based on tree-mode. Testing with examples of MCNC, we find the optimization is encouraging.