High Performance 3D Glass-Embedded Inductors Fabricated by a Glass Reflow Process

摘要

Inductor is a key passive component in radio-frequency integrated circuits (RFICs). Compared with other components in the circuit, inductor has a bigger size, hence its miniaturization is critical for integrated circuit system. Most of conventional on-chip inductors fabricated on silicon substrates are planar structures, and have low quality factor (Q) due to the substrate loss of low-resistivity silicon substrate and the ohmic loss of thin-metal strips. Some inductors of three-dimensional structure have the ability to reduce the influence of the substrate loss for better performance. However, the disadvantage is their limited design flexibility of space. This paper presents the novel way using a glass reflow process to fabricate three-dimensional glass-embedded inductors. This work focuses on the glass reflow process to fabricate void-free embedded inductor structure. The inductor prototype has been successful demonstrated. High-aspect-ratio glass-embedded structure formed from highly conductive materials has smaller energy dissipation, resulting in a high quality factor (Q). In addition, embedded structures releases more surface and gain large space utilization rate for system integration. The novel fabrication process as well as the TGV process would have potential applications on compact RF MEMS system integration.