12.8 Special Session: EDA Challenges in Monolithic 3D Integration: From Circuits to Systems
Monolithic-3D integration (M3D) has the potential to improve the performance and energy efficiency of 3D ICs over conventional TSV-based counterparts. By using significantly smaller inter-layer vias (ILVs), M3D offers the "true" benefits of utilizing the vertical dimension for system integration: M3D provides ILVs that are 100x smaller than a TSV and have similar dimensions as normal vias in planar technology. This allows M3D to enable high-performance and energy-efficient systems through higher integration density, flexible partitioning of logic blocks across multiple layers, and significantly lower total wire-length. From a system design perspective, M3D is a breakthrough technology to achieve "More Moore and More Than Moore," and opens up the possibility of creating manycore chips with multi-tier cores and network routers by utilizing ILVs. Importantly, this allows us to create scalable manycore systems that can address the communication and computation needs of big data, graph analytics, and other data-intensive parallel applications. In addition, the dramatic reduction in via size and the resulting increase in density opens up numerous opportunities for design optimizations in the manycore domain.
12.8.1 M3D-ADTCO: MONOLITHIC 3D ARCHITECTURE, DESIGN AND TECHNOLOGY CO-OPTIMIZATION FOR HIGH ENERGY-EFFICIENT 3D IC
12.8.2 DESIGN OF A RELIABLE POWER DELIVERY NETWORK FOR MONOLITHIC 3D ICS
12.8.3 POWER-PERFORMANCE-THERMAL TRADE-OFFS IN M3D-ENABLED MANYCORE CHIPS
Monolithic 3D (M3D) technology enables unprecedented degrees of integration on a single chip. The miniscule monolithic inter-tier vias (MIVs) in M3D are the key behind higher transistor density and more flexibility in designing circuits compared to conventional through silicon via (TSV)-based architectures. This results in significant performance and energy-efficiency improvements in M3D-based systems. Moreover, the thin inter-layer dielectric (ILD) used in M3D provides better thermal conductivity compared to TSV-based solutions and eliminates the possibility of thermal hotspots. However, the fabrication of M3D circuits still suffers from several non-ideal effects. The thin ILD layer may cause electrostatic coupling between tiers. Furthermore, the low-temperature annealing degrades the top-tier transistors and bottom-tier interconnects. An NoC-based manycore design needs to consider all these M3D-process related non-idealities. In this paper, we discuss various design challenges for an M3D-enabled manycore chip. We present the power-performance-thermal trade-offs associated with these emerging manycore architectures.