Au-In/Polymer Hybrid Bonding and Reliability of 1700 PPI Micro-LED Device

Integration technology is a key issue in the development of high-performance Micro LED display. An innovative Au/In-polymer hybrid bonding technique was employed in high-resolution Micro-LED devices to enhance their reliability in this article. There is little difference in optical and electrical performance data between devices filled and unfilled with polymers. Furthermore, the reliability of Micro-LEDs in steady-state temperature-humidity test was significantly improved by filling the metallic interconnect structure with polymer materials. Compared to the traditional flip-chip bonded device, the hybrid bonded device demonstrated reduced brightness attenuation, slower growth of series resistance, and more stable spectral performance after 85 °C/85% RH hygrothermal aging. In addition, the shear strength of the hybrid bonded device was 11.7 times greater than that of the flip-chip bonded device, which was attributed to the effective filling of the polymer in the interconnection gap. The polymer offers physical support and electrical isolation for the device, providing a reliable protection mechanism against water vapor erosion. This study promotes the application of hybrid bonding in the field of heterogeneous integration of Micro-LEDs, which provides a solution for the reliability improvement of Micro-LED.