Fast Fixed-Outline 3-D IC Floorplanning With TSV Co-Placement

Through-silicon vias (TSVs) are used to connect inter-die signals in a 3-D IC. Unlike conventional vias, TSVs occupy device area and are very large compared to logic gates. However, most previous 3-D floorplanners only view TSVs as points. As a result, whitespace redistribution is necessary for TSV insertion after the initial floorplan is computed, which leads to suboptimal layouts. In this paper, we propose a very efficient 3-D floorplanner to simultaneously floorplan the functional modules and place the TSVs and to optimize the total wirelength under fixed-outline constraint. Compared to the state-of-the-art 3-D floorplanner with TSV planning, our design consistently produces better floorplans with 15% shorter wirelength and 31% fewer TSVs on average. Our algorithm is extremely fast and only takes a few seconds to floorplan benchmarks with hundreds of modules compared to hours as required by the previous state-of-the-art floorplanner.