Paper 14093-55
Paper 14093-55
Flux-free bonding of photonic components using laser-induced forward transfer of AuSn thin films and laser soldering
15 April 2026 • 15:15 - 15:30 CEST | Curie A (Niveau/Level 1)
Abstract
We report the use of Laser-Induced Forward Transfer (LIFT) for the deposition of eutectic AuSn thin films intended for flux-free bonding of optoelectronic components on photonic integrated circuits. Two solid-phase AuSn donors, with thicknesses between 100 nm and 500 nm, were employed to achieve LIFT printing of uniform, and well-defined pads on SiO₂/Si substrates while maintaining the eutectic composition. Subsequent flux-free bonding was performed using a 975 nm CW laser. Preliminary results demonstrate reproducible pattern formation, smooth morphology, and stable electrical behavior of the bonded structures. Ongoing work focuses on optimizing parameters such as melting point and joint strength, confirming that sub-2 μm LIFT-printed AuSn films offer a precise, low-thermal-budget route for advanced photonic integration.
Presenter
Nektaria Protopappa
National Technical Univ. of Athens (Greece)
Nektaria Konstantina Protopappa is a Junior Researcher at the Laser Materials Printing and Processing (LMP), headed by Prof. Ioanna Zergioti, and located at the Physics Department of the National Technical University of Athens (NTUA). She received her Diploma in Physics from the University of Crete in 2022, where she also conducted research at the Institute of Electronic Structure and Laser (IESL) of the Foundation for Research and Technology – Hellas (FORTH). In 2025, she earned her Master’s degree in Microsystems and Nanodevices from NTUA. Her current research focuses on material processing for electronic applications, including Laser-Induced Forward Transfer (LIFT), laser soldering, and laser-assisted bonding and packaging technologies. She is particularly interested in developing and optimizing laser-based processes for advanced interconnection materials and next-generation device manufacturing.