Expandable Chip Stacking Method for Many-core Architectures Consisting of Tiny Chips

The increase of recent non-recurrent engineering cost (design, mask and test cost) have made large System-on-Chip (SoC) difficult to develop especially with advanced technology. We radically explore an approach for cheap and flexible chip stacking. To connect a large number of small chips for building a large scale system, a novel chip stacking method called the staggered stacking is proposed that enables the system to be extended to x and y dimensions, not only to z dimension. For such flexible inter-chip communication, we use Inductive coupling ThruChip Interface (TCI). Here, a novel chip staking layout, and its deadlock-free routing design for the case using multi-core chips are shown. The network with 256 nodes formed by the proposed stacking improves the latency of 2D mesh by 13.8% and the performance of NAS Parallel Benchmarks by 6.7% on average compared to that of 2D mesh.