SHF: Small: Collaborative Research: Managing Thermal Integrity in Monolithic 3D Integrated Systems

Sponsor: National Science Foundation

Award Number: CCF-1909027

Abstract:

Monolithic three-dimensional (M3D) technology is an emerging integrated circuit (IC) paradigm to maintain the exponential growth in transistor density in future computing platforms. At a time when the fundamental limits of conventional scaling are fast approaching, M3D ICs have the potential to enhance energy efficiency at lower cost. A fundamental challenge in building complex M3D ICs is to efficiently control the on-chip temperature. This project will develop a systematic framework to assess chip-level thermal characteristics and ensure thermal integrity in M3D ICs. Since temperature management is one of the most challenging roadblocks for emerging M3D systems, the proposed research will have a transformative impact on future semiconductor electronics. The methodologies to be developed will be tightly coupled with recent advances in M3D fabrication process, thereby strengthening the applicability and impact of this research.

During the past decade (and particularly last several years), IC research community has witnessed highly encouraging developments on reliably fabricating M3D chips. Despite the growing interest on multiple aspects of this emerging technology (such as process optimization, computer-aided design, heterogeneous integration), a reliable framework for ensuring thermal integrity in dense M3D systems does not yet exist. This research fills this gap with specific emphasis on leveraging M3D-specific characteristics during both efficient thermal analysis and temperature management. These unique characteristics include the existence of large number of thin layers, lower temperature requirements during the fabrication process of upper tiers, capability for flexible partitioning at different granularity, exacerbated joule heating, and strong thermal cross-talk among the tiers. The primary objective is to facilitate future progress on both design and fabrication aspects of M3D technology by developing a comprehensive framework for managing thermal issues. This objective will be achieved through (1) compact yet sufficiently accurate thermal models with high fidelity and (2) M3D-specific design techniques to ensure thermal integrity. The results of this research will provide a better understanding of unique thermal characteristics in M3D chips and help mitigate these thermal issues through efficient analysis and management.

This award reflects NSF’s statutory mission and has been deemed worthy of support through evaluation using the Foundation’s intellectual merit and broader impacts review criteria.

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