A Coherent Compact Thermal Network Model (CTM) for High-Precision and Efficient Temperature Prediction in CoWoS Packaging

Chiplet-based heterogeneous integration, exemplified by CoWoS packaging, delivers high scalability and performance but introduces critical thermal challenges from power density escalation and inter-chiplet thermal coupling. This study presents a coherent compact thermal network model (CTM) for junction temperature prediction in CoWoS packaging, integrating self-heating effects and thermal interactions across chiplets through a systematic approach. The model incorporates equivalent orthotropic submodels to simplify microstructures such as TSVs, u-bumps, and C4 bumps, while maintaining computational efficiency. A key innovation lies in the novel calculation of coupling thermal resistances between chiplets using analytical solutions for heat spreading in orthotropic materials and superposition principles, enabling the CTM as a coherent system. Validated against COMSOL simulations, the CTM achieves high accuracy (errors ˂4% for primary heat sources) and reduces simulation time by over 99% compared to finite element methods (FEM) and latest related work.