Thermal-mechanical coupling analysis of Micro-LED bonding based on copper pillar bump

With the rapid development of automotive electronics and near-eye display, more stringent requirements are put forward for the heterogeneous integration technology of Micro-LED, especially in interconnect structure. The copper pillar bumps with better electrical conductivity, thermal conductivity and mechanical properties can meet the packaging requirements of higher density and smaller pitch for application of Micro-LED array. The application of copper bumps in small pitch interconnect structures have been discussed in many studies while the application of copper pillar bumps in Micro-LED interconnection is currently rare. An equivalent model method of simulation combined with sub-model technique is proposed in this paper. The feasibility and accuracy of the equivalent method was investigated. Simulation of Micro-LED bonding process based on copper pillar bumps with equivalent method was performed. Low-temperature (40 °C) and high-temperature (280 °C) were applied to the upper bonding interface respectively to investigate the influence of bonding temperature on the stress of the device. Micro-LED bonding experiment was performed to validate the results of bonding simulation.