An effective analytical method for thermal stresses analysis of heterogeneous integration system in display

Abstract

The heterogeneous integration system in display (HiSID) is a brand new architecture in accordance with the demand and technology trends of the next generation terminal device, and the new development architecture consists of multi-interactive function units are applied to solve the issue of non-fully-utilized area on the display module. However, the technologies challenge of thermal management increase when these interactive components are integrated into display modular system. Especially, the reliability of HiSID model are often affected by the temperature change due to the mismatch of coefficients of thermal expansion (CTE) and elastic modulus among functional components, solders, and substrate. In this paper, an effective analytical model is systematically established to promptly simulate the thermal shock performance to verify and further discuss the reliability of HiSID structure, and it is different from traditional finite element method. The total strains of entire HiSID models are decomposed into the uniform strain and bending strain, and the bending strain of segmented solder joints are modified. And the longitudinal stresses of each component are calculated based on the product of Young's modulus and total strains. The interfacial stress along the heterogeneous interfaces are expressed as exponential stress function, which satisfy the variation tendency from free-edge to the position away from the boundary. The inner stresses and interfacial stresses induced by temperature change from present analytical method are also validated against those results of the finite element method. Moreover, the FR4-based and glass-based substrate for HiSID model are compared to demonstrate the better thermal-mechanical behaviors.