2015 Volume 135 Issue 12 Pages 1535-1544
In modern VLSI designs, a flip-chip package is widely used to meet the higher integration density and the larger I/O counts of circuits. Recently the I/O buffers are mapped onto bump balls without changing the module placement using re-distribution layer (RDL) in flip-chip designs. In this research, a sorting-based I/O connection assignment and non-Manhattan RDL routing method is proposed for area I/O flip-chip designs. The approach initially assigns the I/O buffers to bump balls by sorting the Manhattan distance between them. Three kinds of pair-exchange procedures are then carried out to improve the initial assignment. Then to shorten the wire length, non-Manhattan RDL routing is adopted to connect the I/O buffers and bump balls. Finally some un-routed connections are ripped up and rerouted. The experimental results show that the proposed method is able to obtain the routes with shorter wire length in reasonable CPU times.
The transactions of the Institute of Electrical Engineers of Japan.C
The Journal of the Institute of Electrical Engineers of Japan