3D logarithmic interconnect: Stacking multiple L1 memory dies over multi-core clusters

In this paper we propose two synthesizable 3D network architectures: C-LIN and D-LIN, which allow modular stacking of multiple L1 memory dies over a multi-core cluster with a limited number of processing elements (PEs). Two Through Silicon Via (TSV) technologies are used: the state of the art Micro-bumps and the promising and dense Cu-Cu Direct Bonding, with consideration of the ESD protection circuits. Our results demonstrate that, in processor-to-L1-memory context, C-LIN and D-LIN perform significantly better than traditional network on chips and simple time-division multiplexing buses, and they achieve comparable speed vs. their 2D counterparts, while enabling modularity: from 256KB to 2MB L1 memory configurations with a single mask set.