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

单片三维（M3D）技术是一种新兴的集成电路（IC）模式，可以在未来的计算平台中保持晶体管密度的指数级增长。在传统规模的基本限制迅速接近的时候，M3D集成电路有潜力以更低的成本提高能源效率。构建复杂的M3D集成电路的一个基本挑战是有效地控制片上温度。该项目将开发一个系统框架来评估芯片级热特性，并确保M3D集成电路的热完整性。由于温度管理是新兴M3D系统最具挑战性的障碍之一，因此拟议的研究将对未来的半导体电子产生变革性影响。所开发的方法将与M3D制造工艺的最新进展紧密结合，从而加强本研究的适用性和影响。在过去的十年中（特别是最近几年），IC研究界在可靠制造M3D芯片方面取得了令人鼓舞的进展。尽管人们对这一新兴技术的多个方面（如工艺优化、计算机辅助设计、异构集成）越来越感兴趣，但目前还没有一个可靠的框架来确保致密M3D系统的热完整性。这项研究填补了这一空白，特别强调在有效的热分析和温度管理中利用m3d特定的特性。这些独特的特性包括大量薄层的存在、上层制造过程中较低的温度要求、不同粒度的灵活划分能力、加剧的焦耳加热以及层间强的热串扰。主要目标是通过开发一个管理热问题的综合框架，促进M3D技术在设计和制造方面的未来进展。这一目标将通过(1)紧凑但足够精确的高保真热模型和(2)m3d特定设计技术来实现，以确保热完整性。这项研究的结果将更好地理解M3D芯片独特的热特性，并通过有效的分析和管理帮助缓解这些热问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.