Mechanical Properties of Flip-Chip Bonding Structures for Micro-Led Devices: Cu-Cu Bonding with Passivation Layer and Indium Bumps Bonding

A traditional bonding structure with indium bumps and a new bonding structure with passivation layer using Cu bumps were simulated to bond Micro-LED and substrate. Anand model and bilinear isotropic hardening model were used to characterize the viscoplastic behavior of In and the plastic behavior of composite structure simplified from the combination of Cu and Au, respectively. Mechanical properties of two kinds of micro-display devices with different bonding structures were analyzed by the ANSYS finite element method and the thermo-mechanical coupling field. The deformation and stress of the micro-display device using Cu-Cu bonding structure with passivation layer are reduced by 19.5% and 59.1% compared with the device bonded by In bumps.