Efficiency and Precision Performance of Laser Bonding Technology in Micro-LED Packaging Processes

This study presents the fabrication and integration of vertically stacked dual-color Micro-LEDs using laser eutectic bonding with Au–Sn alloy. A blue flip-chip and a green vertical-array Micro-LED were individually processed, including epitaxial etching, transparent electrode formation, and passivation. A nanosecond-pulsed 1064 nm fiber laser was employed to induce localized eutectic bonding at 233 °C, forming robust Au5Sn intermetallic compounds at the interface. SEM-EDX analysis confirmed the presence of eutectic and Au₅Sn phases, validating the metallurgical integrity of the joint. Electrical characterization revealed minimal threshold voltage shift post-bonding, indicating preserved device performance. The bonding process demonstrated precise alignment, thermal stability, and mechanical reliability, enabling scalable integration of stacked Micro-LEDs for advanced display applications.