A polyamide-facilitated soldering approach for Mini LED precise alignment leveraging 3D interfacial networks

Abstract

Driven by the need for improved quality, energy efficiency, and visual innovation, display technology has evolved from CRT to Mini LED. However, the transfer process in Mini LED assembly poses challenges in precision. This study addressed the displacement issue during the transfer process by investigating the synergistic effects of solder and functional organic chemicals. Through the Mini LED assembly process, with the Mini LED size measuring 150 μm (length) ∗ 100 μm (width) ∗ 70 μm (thickness), polyamide was identified as a facilitator for precise alignment, which enhanced self-alignment capabilities by 68.8 % and improved the accuracy on self-aligned distance from 12.5 μm to 21.1 μm in Mini LED packaging. Through the powder coalescence approach, further extensive analysis using XPS, SEM, FTIR, and DSC reveals the synergistic effects. It supports the proposed three-dimensional polyamide-tin ion coordination interfacial network construction mechanism that facilitates solder-to-solder self-alignment and coalescence. This study provides insight into such a polymer-metal ion 3D coordination network for Mini LED precise alignment, which is promising for mass production.