Communication Considerations for Silicon Interconnect Fabric

Silicon interconnect fabric (Si-IF) is a heterogeneous integration platform for ultra-large systems. Unpackaged dies are attached directly to a Si wafer at fine vertical interconnect pitch (2 to 10 μm) and small inter-die spacing (≤ 100 μm). The Si-IF replaces conventional interposers, packages, and printed circuit boards, and provides a single-hierarchy integration construct. Communication on the Si-IF platform is a key system-level challenge. Various approaches for local, semi-global (regional), and global communication are discussed in this paper. A network on interconnect fabric, based on intelligent utility dies, to support various system-level services, including communication, is introduced. Binning of communication schemes based on simulations of latency and energy is performed. A related design space, evaluated in terms of energy-latency product, with respect to distance is offered. Finally, external communication aspects are also discussed.