Thermal Implications of Non-Uniform Power in BSPDN-Enabled 2.5D/3D Chiplet-based Systems-in-Package using Nanosheet Technology

TL;DR

This paper investigates how non-uniform power distributions affect thermal management in nanosheet-based 2.5D/3D chiplet systems, revealing that realistic power maps are crucial for accurate thermal analysis and design.

Contribution

It introduces high-resolution thermal simulation methods using non-uniform power maps to evaluate thermal effects in nanosheet-enabled 3D SiP, highlighting limitations of uniform power assumptions.

Findings

Uniform power models underestimate peak temperatures.

BSPDN configurations face thermal penalties under realistic workloads.

Fine-grained power maps improve thermal accuracy in design.

Abstract

Advances in nanosheet technologies have significantly increased power densities, exacerbating thermal management challenges in 2.5D/3D chiplet-based Systems-in-Package (SiP). While traditional thermal analyses often employ uniform power maps to simplify computational complexity, this practice neglects localized heating effects, leading to inaccuracies in thermal estimations, especially when comparing power delivery networks (PDN) in 3D integration. This work examines the thermal impact of non-uniform power distributions on SiPs utilizing frontside (FSPDN) and backside (BSPDN) power delivery approaches. Using high-resolution thermal simulations with non-uniform power maps at resolutions down to 5 micrometers, we demonstrate that uniform power assumptions substantially underestimate peak temperatures and fail to reveal critical thermal differences between BSPDN and FSPDN configurations in 3D scenarios. Our results highlight that BSPDN configurations in 3D, although beneficial in simplified uniform scenarios, exhibit pronounced thermal penalties under realistic, localized workloads due to limited lateral heat spreading. These findings emphasize the necessity of adopting fine-grained, workload-aware power maps in early-stage thermal modeling to enable accurate PDN assessment and informed thermal-aware design decisions in advanced nanosheet-based 3D SiP.