03. Electronics Packaging and Thermal Management

Thermal spreading resistance is recognized as a crucial factor in the design of electronic cooling devices, significantly impacting overall thermal resistance and surface temperature. The optimization of this parameter is essential for improving the performance and reliability of high-heat-flux electronic systems. In this study, the effects of key parameters on thermal spreading resistance in electronic cooling applications were analytically investigated. An analytical model was developed to examine the relationship between substrate thickness, heat transfer coefficient, input heat load, and surface area ratio. The model was solved using finite element analysis, and a parametric study was conducted to explore a wide range of conditions relevant to electronic cooling applications. It was found that the conventional understanding of spreading resistance holds true only for systems with low heat transfer coefficients. For coefficients below 2000 W/m²K, thermal resistance was observed to decrease consistently with increasing substrate thickness. However, a non-monotonic relationship was revealed for high-performance cooling systems with heat transfer coefficients exceeding 2000 W/m²K, such as those employing two-phase cooling. In these cases, thermal resistance was found to initially decrease with increasing substrate thickness but then begin to rise, indicating an optimal thickness for minimizing spreading resistance. The results demonstrated that the optimal substrate thickness is not a fixed value but depends on a complex interplay of factors. This finding has significant implications for the design of advanced electronic cooling systems, particularly those utilizing two-phase cooling technologies. The importance of considering multiple parameters in thermal management design was highlighted, providing valuable insights for optimizing the performance of high-heat-flux electronic devices. This study contributes to a more comprehensive understanding of spreading resistance in electronic cooling applications, challenging the conventional wisdom and providing a nuanced perspective on thermal management strategies for next-generation electronic systems.