Review on Fan-Out Packaging of Light-Emitting Diodes: Process Route, Manufacturing Reliability, and Performance Optimization

Abstract With the continuous growth of the demand for high resolution and high contrast in the display field, light-emitting diodes (LED) are evolving toward miniaturization and smaller pitch. Fan-out packaging (FOP), represented by fan-out wafer level packaging (FOWLP) and fan-out panel level packaging (FOPLP), being an advanced LED packaging technology, does not require a substrate or wire bonding while featuring small size, low cost, and the ability to provide efficient electrical interconnection and good heat dissipation for LED chips. It is a promising packaging solution that promotes the miniaturization of LEDs. This article introduces two types of FOPs, FOWLP and FOPLP, and three FOP process routes: chip-first and face-down, chip-first and face-up, and redistribution-first (RDL-first), and reviews the research progress on the manufacturing reliability issues of fan-out packaging light-emitting diodes, including die shift and warpage deformation, as well as the research progress in optimizing the electrical, optical, and flexible performance of fan-out packaging light-emitting diodes.