Y. Shen¹, P. Rozanski², X. Yang³, D. Fang^3
1TRUMPF Hüttinger GmbH + Co. KG, Freiburg im Breisgau, Germany
²TRUMPF Huettinger Sp. z o.o., Zielonka, Poland
³TRUMPF Huettinger Electronics (Taicang) Co. Ltd. Taicang, China
Through-Glass Via (TGV) metallization is emerging as a key technology for next-generation interconnects in advanced packaging and display systems, requiring highly directional and continuous copper seed layers within deep, high-aspect-ratio structures. Conventional sputtering frequently encounters limitations in ion momentum transport, entrance shadowing, and unstable sheath formation on insulating glass substrates.
This work presents an industrially scalable high-power-impulse magnetron sputtering (HiPIMS) approach combined with a fully synchronized 13.56 MHz RF bias that exploits the transient plasma evolution of HiPIMS pulses. Synchronizing the RF-bias waveform with the metal-ion–rich mid-late phase of the pulse minimizes reflected-power events, stabilizes ion–sheath coupling, and enhances the directed flux of copper ions into narrow vias. Operation in a moderate-peak-power, extended-pulse regime (100~300 µs) generates a prolonged metal-ion window with reduced gas rarefaction and high temporal tolerance, thereby suppressing arcing and mitigating charge accumulation in glass vias. Experimental studies on ~50 µm-diameter vias demonstrate reliable seed-layer continuity at aspect ratios ~10:1, with step-coverage values approaching ~6% and high uniformity across large-area glass substrates. The synchronized HiPIMS–RF-bias scheme therefore offers a robust, geometry-tolerant, and industrially scalable solution for high-aspect-ratio TGV copper seed-layer deposition in advanced packaging architectures.