Fan-Out Panel-Level Packaging of Mini-LED RGB Display

In this study, the feasibility of mini-light-emitting diode (LED) RGB display fabricated by a chip-first fan-out panel-level packaging is investigated. Emphasis is placed on the design, materials, process, fabrication, and reliability of the mini-LED RGB display package on a printed circuit board (PCB). The mini-LEDs under consideration and their sizes are red ( $125 \times 250 \times 100 ~\mu \text{m}$ ), green ( $130 \times 270 \times 100 ~\mu \text{m}$ ), and blue ( $130 \times 270 \times 100 ~\mu \text{m}$ ). The spacing among the RGB mini-LEDs is $80~\mu \text{m}$ , the pixel-to-pixel spacing is also $\sim 80~\mu \text{m}$ , and the pixel pitch is $625~\mu \text{m}$ . The temporary glass panel for making the redistribution layers (RDLs) of the package is $515 \times 510 \times 1.1$ mm in size. To increase the SMT assembly yield on the PCB, the mini-LEDs are grouped into 4( $2 \times 2$ pixels)-in-one surface mount device (SMD), that is, a total of 12 R, B, and G mini-LEDs. A PCB ( $132\,\,mm \times 77$ mm) is designed and fabricated for the drop test of the mini-LED package. Thermal cycling of the mini-LED SMD PCB assembly is also performed by a nonlinear temperature- and time-dependent finite-element simulation.