Architecting 3-D Integrated Circuit Fabric with Intrinsic Thermal Management Features
Abstract
Migration to 3-D provides a possible pathway for future Integrated Circuits (ICs) beyond 2-D CMOS, which is at the brink of its own fundamental limits. Partial attempts so far for 3-D integration using die to die and layer to layer stacking do not represent true progression , and suffer from their own challenges with lack of intrinsic thermal management being among the major ones. Our proposal for 3-D IC, Skybridge, is a truly fine-grained vertical nanowire based fabric that solves technology scaling challenges, and at the same time achieves orders of magnitude benefits over 2-D CMOS. Key to Skybridge’s 3-D integration is the fabric centric mindset, where device, circuit, connectivity, thermal management and manufacturing issues are co-addressed in a 3-D compatible manner. In this paper we present architected fine-grained 3-D thermal management features that are intrinsic components of the fabric and part of circuit design; a key difference with respect to die-die and layer-layer stacking approaches where thermal management considerations are coarse-grained at system level. Our bottom-up evaluation methodology, with simulations at both device and circuit level, shows that in the best case Skybridge’s thermal extraction features are very effective in thermal management, reducing temperature of a heated region by up to 92%.