Active Measurement Wafer for Thermal Characterization in Chiplet-Based Systems

Chiplet-based integration and heterogeneous packaging promise flexibility and performance gains but suffer from significant thermal challenges, especially in highperformance applications such as hardware for AI inference. The major challenges include thermal hotspots, reliability issues due to coefficient-of-thermal-expansion (CTE) mismatch, and nonuniform heat dissipation, which further degrade performance by causing interconnect reliability problems such as electromigration. While various thermal models exist with different levels of granularity, their predictive accuracy is limited without proper experimental validation. Conventional passive test structures provide only coarse insight and lack the flexibility to emulate dynamic workloads. This paper introduces an active measurement wafer that integrates fine-grained programmable heating elements with high-resolution sensing structures. The platform enables realistic reproduction of chiplet power profiles and spatially resolved monitoring of thermal propagation. The main objective of this paper is therefore the introduction of a real-world thermal test wafer for chiplet and advanced packaging integration, enabling direct measurement of thermal behavior. Experimental results demonstrate that the wafer delivers high-quality real measurement data, providing accurate insights into heat propagation, thermal coupling, and the effectiveness of cooling strategies. The proposed approach establishes a novel methodology for bridging simulation and experiment, ultimately improving the design and reliability of advanced semiconductor systems.