HyPlace-3D: A Hybrid Placement Approach for 3D ICs Using Space Transformation Technique

This paper proposes a hybrid 3D placement approach which can reduce the number of TSVs while getting short wirelength. Although existing 3D analytical placement approaches can get short wirelength, they usually use a large number of TSVs. Moreover, because cells may be allocated to two tiers by their analytical placement formulations, placement utilization cannot be calculated precisely which may increase the difficulty in cell legalization. To get a less number of TSVs, our approach first allocates cells to tiers by a partitioning algorithm and maintains the result in the following stages. More importantly, we propose a novel 2D-2-3D analytical placement approach according to the space transformation technique. This approach can spread cells over 3D space while optimizing 3D wirelength by a 2D analytical placement formulation. Moreover, placement utilization can be calculated accurately in this approach since cells and TSVs are spread over a 2D plane instead of a 3D space. Experimental results show that our approach can obtain short wirelength and significantly fewer TSVs than previous works.