Whitespace Insertion for Through-Silicon Via Planning on 3-D SoCs

As technology advances, 3-D ICs can significantly alleviate the interconnect problem coming with the decreasing of feature size and are promising for heterogeneous integration. In 3-D ICs, one of the key challenges is the vertical technology, using through-silicon via (TSV) for different device layers connection. In this paper, by noticing the TSV assignment comes under the influence of the whitespace distribution in a given 3-D floorplan, we proposed an algorithm called whitespace insertion (WSI) based on the floorplan-representation Sequence Pair to make the whitespace distribution in the given floorplan more reasonable for TSV insertion. When given 3-D circuit placement or floorplan results, we also proposed a minimum spanning tree based algorithm for TSV assignment to minimize the total wire length, assuming each net may have at most one TSV on each device layer. Experimental results show that, in the given 3-D floorplans there is a huge gap about 45.54% of the wire length increase between the ideal and the practice. And based on our method, the total wire length can be reduced by 13% on average without changing the chip area.