Investigation of fabricated Through Glass Via (TGV) process by inductively coupled plasma reactive ion etching of quartz glass

Abstract

In this paper, we report the fabrication process of Through Glass Via (TGV) structure and basic design rules for glass based Three-Dimensional Integrated Circuit (3D-IC) packaging as well as a process flow for glass interposer applications. Quartz glass materials have been widely used in many packaging applications for micro electromechanical systems (MEMS), optical devices, and biomedical chips. Our work focuses on a 3D-IC package approach based on the use of thin glass as a substrate material. For through-glass-vias, holes were etched in glass wafers by photolithography and inductively coupled plasmareactive ion etching (ICP-RIE) technologies and evaluated. The results of fabrication of TGV morphology showed a very good compromise between wafer thickness, TGV shape and via diameter for vertical interposer with 50 µm diameters in 150 µm thin quartz glass wafer still very stable for thin wafer processing without complicated processes.