Closing the power delivery/heat removal cycle for heterogeneous multi-scale systems

The semiconductor industry is poised to continue the historic Moore's law trend of doubling the level of integration every 1.5-2 years, even as the virtuous cycle benefits of Dennard scaling are quickly vanishing. Once devices no longer scale laterally, the only way to continue to increase areal density is by going vertical using 3D-IC. However, 3D-IC raises several fundamental difficulties in addition to the clear fabrication challenges: as the number of physical layers in a 3D-IC stack increases, from the present 2.5D multi-layer solutions (with an interposer, or only a couple of layers), to true 3D many-layer stacks, the energy cycle problem of delivering power to and removing heat from the 3D stack become daunting. The main reason for this power wall is the mismatch between the volumetric (cubic) power consumption and heat dissipation in 3D-IC, and the areal (quadratic) power delivery and heat removal through a 2D surface (top and/or bottom of the stack). In this paper we propose MultiSpot, a framework to provide fundamental solutions to the 3D-IC power wall that are also practical.