Interconnection Reliability of Mini LEDs for Display Applications

Micro/Mini-LED displays have many advantages compared to other displays. However, the reliability data required for the commercialization of mini-LEDs is insufficient. In this study, we analyzed the reliability of mini-LEDs by comparing the shear strength and microstructure of their solder joints before and after conducting a reliability test. We first performed a simultaneous transfer and bonding (SITRAB) process to mount mini-LEDs on a substrate. To analyze the effect of underfill on mini-LED reliability, we compared those both with and without SITRAB adhesive. The mini-LED with SITRAB adhesive showed a small decrease in shear strength after the reliability test, whereas the mini-LED without SITRAB adhesive showed a large decrease in shear strength after the reliability test. As a result of measuring the optical characteristics of the LED after the reliability test, it was observed that there was no change in the characteristics of the mini-LED. It can be concluded that the SITRAB process with SITRAB adhesive improved the reliability of mini-LEDs.