High Inductance Density Solenoid Inductors Based on Glass Blind Groove for 3-D Glass Packaging

Nowadays, the manufacture of glass-based integrated devices are typically accomplished using the through glass vias (TGVs) and redistribution layer (RDL) technologies. However, traditional RDL using photolithography is a complex and costly process, and inevitably introduces considerable parasitic parameters at the junction of surface lines and vias. To address these challenges, a proactive approach involving the prefabrication of glass blind grooves has emerged. Nevertheless, current blind groove fabrication relies on lithography and etching, which impose limitations on aspect ratio and shape control. In this paper, based on TGV technology, a novel approach is proposed to replace the traditional RDL process with glass blind groove technology, and the reliability of the glass blind groove is analyzed. This strategy has significantly simplified the process steps and reduced manufacturing costs, and both blind grooves and through-vias can be simultaneously produced by the laser-induced wet etching (LIWE) technology. Glass blind grooves can be achieved with an adjustable aspect ratio. As an example, an inductor using glass blind groove technology is fabricated and measured. An inductance density of 65.7 nH/mm
²
and a
$Q$
factor of 40 can be achieved. The proposed 3-D solenoid inductor can be demonstrated a dual advantage of high integration and performance, which provides a new idea for the preparation of three-dimensional integrated devices.