Design, Materials, Process, Fabrication, and Reliability of Mini-LED RGB Display by Fan-Out Panel-Level Packaging

In this study, the feasibility of mini-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 (
$125 \times 250 \times 100\mu \mathrm{m}$
), Green (
$130\times 270\times 100 \mu \mathrm{m}$
), and Blue (
$130 \times 270\times 100\mu \mathrm{m}$
). The spacing among the RGB mini-LEDs is
$80\mu \mathrm{m}$
, the pixel-to-pixel spacing is also
$\sim 80\mu \mathrm{m}$
, and the pixel pitch is
$625\mu\mathrm{m}$
. The temporary glass panel for making the RDLs of the package is
$515 \times 510\times 1.1\text{mm}$
in size. In order to increase the SMT assembly yield on the PCB, the mini-LEDs are grouped into
$4(2\times 2\ \text{pixels})$
in one SMD (surface mount device), i.e., a total of 12 R, B, and G mini-LEDs. A PCB (
$132\text{mm}\times 77\text{mm}$
) 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.