Finite Element Simulation of Electrothermal and Mechanical Coupling in Micro-LED Array Based on Two Bump Shapes

Micro-LED has attracted more attention due to its unique photoelectric properties, such as high brightness, high energy efficiency, high stability and other characteristics, which facilitate its widespread application. Bumps can be used for electrical connections and heat transfer paths as well as structural supports that affect the reliability of Micro-LED devices. Hybrid bonding enhances the reliability and longevity of electronic devices while also ensuring the compatibility of bonding process. Currently, there is limited finite element simulation research on Micro-LEDs, particularly regarding electrothermal and mechanical multi-physical field simulations. Herein, the electrothermal and mechanical coupling of a quarter of a 6×6 Micro-LED array model was analyzed using COMSOL Multiphysics simulation software and the finite element method. The analysis primarily focused on the stress and displacement of bumps in the hybrid bonding model. The optimal combinations of different bump materials (indium-In, tin-Sn) and filling materials (epoxy resin-EP and benzocyclobutene-BCB) were obtained. The results indicate that BCB is a more suitable filling material, while In is preferable as a bump material. Furthermore, variations in thermal stress and displacement of cylindrical and circular-truncated cone bumps of different aspect ratios were analyzed. This paper provides an idea for optimizing the fabrication of Micro-LED bumps and bonding processes.