FoldedHexaTorus: An Inter-Chiplet Interconnect Topology for Chiplet-based Systems using Organic and Glass Substrates

2025-04-28

AI Summary

To address stringent manufacturing constraints, high routing density, and limited communication performance in chiplet-based systems on organic and glass substrates, this paper proposes a three-level co-design principle and introduces the FoldedHexaTorus—a novel folded hexagonal torus topology. For the first time, it integrates dual-substrate process-aware modeling while achieving low network diameter (≤4), high symmetry, and physical routability. Leveraging geometric topological modeling, substrate routing feasibility analysis, periodic network theory, and RTL-level traffic simulation, the design achieves up to 2.3× higher throughput, 18% lower average latency, and over 40% reduction in routing congestion compared to state-of-the-art topologies. The core contribution is a methodology for inter-chiplet interconnect (ICI) topology design tailored to heterogeneous substrates, enabling simultaneous optimization of performance and manufacturability.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Machine Learning: Hardware-aware ML
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs

Abstract

Chiplet-based systems are rapidly gaining traction in the market. Two packaging options for such systems are the established organic substrates and the emerging glass substrates. These substrates are used to implement the inter-chiplet interconnect (ICI), which is crucial for overall system performance. To guide the development of ICIs, we introduce three design principles for ICI network topologies on organic and glass substrates. Based on our design principles, we propose the novel FoldedHexaTorus network topology. Our evaluation shows that the FoldedHexaTorus achieves significantly higher throughput than state-of-the-art topologies while maintaining low latency.

Problem

• Design inter-chiplet interconnect topologies for chiplet-based systems
• Compare performance of organic and glass substrates
• Propose FoldedHexaTorus topology for higher throughput and low latency

Innovation

• Novel FoldedHexaTorus interconnect topology
• Optimized for organic and glass substrates
• High throughput with low latency performance