Cool-3D: An End-to-End Thermal-Aware Framework for Early-Phase Design Space Exploration of Microfluidic-Cooled 3DICs

TL;DR

The paper tackles the challenge of early-phase design space exploration for thermal-aware 3DICs by introducing Cool-3D, an end-to-end framework that unifies performance (gem5), power (McPAT + CACTI-3DD), and thermal (HotSpot 7.0) modeling with built-in microfluidic cooling and a non-parameterizable customization pathway. It provides a front-end unified interface, a back-end toolchain, and a floorplan designer plus a microfluidic cooling strategy generator to enable broad, fine-grained DSE. Three case studies demonstrate the framework’s ability to model stacking configurations, cooling strategies, and microarchitectural changes while accurately predicting thermal behavior, with open-source release planned on GitHub for reproducibility. The work highlights the potential for accelerated, thermally aware 3DIC design decisions and sets the stage for future enhancements, including RL-based optimization and support for emerging architectures like PIM/PNM.

Abstract

The rapid advancement of three-dimensional integrated circuits (3DICs) has heightened the need for early-phase design space exploration (DSE) to minimize design iterations and unexpected challenges. Emphasizing the pre-register-transfer level (Pre-RTL) design phase is crucial for reducing trial-and-error costs. However, 3DIC design introduces additional complexities due to thermal constraints and an expanded design space resulting from vertical stacking and various cooling strategies. Despite this need, existing Pre-RTL DSE tools for 3DICs remain scarce, with available solutions often lacking comprehensive design options and full customization support. To bridge this gap, we present Cool-3D, an end-to-end, thermal-aware framework for 3DIC design that integrates mainstream architectural-level simulators, including gem5, McPAT, and HotSpot 7.0, with advanced cooling models. Cool-3D enables broad and fine-grained design space exploration, built-in microfluidic cooling support for thermal analysis, and an extension interface for non-parameterizable customization, allowing designers to model and optimize 3DIC architectures with greater flexibility and accuracy. To validate the Cool-3D framework, we conduct three case studies demonstrating its ability to model various hardware design options and accurately capture thermal behaviors. Cool-3D serves as a foundational framework that not only facilitates comprehensive 3DIC design space exploration but also enables future innovations in 3DIC architecture, cooling strategies, and optimization techniques. The entire framework, along with the experimental data, is in the process of being released on GitHub.

Figures (13)

• Figure 1: An illustration of working mechanism of microfluidic cooling applied in 3DICs.
• Figure 2: Overview of an end-to-end thermal simulation toolchain, comprising a performance model that generates switching activities, a power model that estimates dynamic (dyn. pow.) and static power (stat. pow.), and a thermal model that predicts heat generation.
• Figure 3: An overview of the proposed Cool-3D flow, composing a front-end interface and a back-end toolchain.
• Figure 4: Illustration of the role Cool-3D plays in a typical design flow for 3DICs.
• Figure 5: An illustration of mainstream microfluidic cooling patterns, (a) vertically aligned pattern, (b) 90-degree bent pattern with two pairs of inlets and outlets.