From Materials to OSAT: SITRAB Technology for Scalable Micro-LED Transfer and Bonding

Micro-LED technology is widely regarded as a key enabler for next-generation displays and emerging photonic applications; however, its large-scale commercialization remains constrained by the complexity, cost, and yield limitations of transfer, bonding, and repair processes. In this masterclass, I present SITRAB (Simultaneous Transfer and Bonding), a laser-based technology developed by ETRI that fundamentally addresses these challenges by integrating micro-LED transfer and bonding into a single process step.

SITRAB is based on a Laser-Assisted/Compression Bonding process combined with a proprietary material that has already been commercialized. The technology eliminates multiple conventional process steps, reduces thermal stress, and enables high-throughput, high-yield assembly. Importantly, SITRAB is not limited to laboratory demonstrations; both the material and the associated equipment have been deployed at OSAT companies, allowing the micro-LED supply chain to transition from R&D to manufacturing readiness.

In addition, ETRI has developed a complete laser-based micro-LED transfer platform, encompassing first-, second-, and third-stage transfer technologies. Using this platform, we demonstrate full-color micro-LED displays fabricated with approximately 20 µm × 30 µm devices, as well as a 4,000 PPI monochrome micro-LED display targeting AR/VR applications.

This masterclass will focus on the practical implementation of SITRAB, lessons learned from commercialization, and its implications for scalable micro-LED manufacturing across advanced packaging, display, and photonic integration ecosystems.