High-Performance Compact 3-D Solenoids for RF Applications

• Published in: IEEE microwave and wireless components letters Vol. 28; no. 6; pp. 479 - 481
• Main Authors: Cayron, Audrey, Viallon, Christophe, Bushueva, Olga, Ghannam, Ayad, Parra, Thierry
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2018; Institute of Electrical and Electronics Engineers
• Subjects: 3-D inductor; above-integrated circuit (IC); Copper; Electronics; Engineering Sciences; high-<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Q inductor; Inductance; Inductors; integrated passive devices (IPDs); Micro and nanotechnologies; Microelectronics; Q-factor; solenoid; Solenoids; Substrates; solenoid; 3-D inductor; high-Q inductor; Above-IC; three-dimensional inductor; Integrated Passive Devices
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2018.2831438

A cost-effective technology is proposed for the integration of very compact and high-performance 3-D solenoid inductors. Based on a two metal level process, it involves a 3-D copper electroplating step for simultaneous integration of vertical and upper sections of coils. Several solenoids fabricated on a glass substrate and ranging from 2.3 to 9.5 nH are presented. The best performance is experimentally achieved by a three-turn 3-nH inductor showing a maximum <inline-formula> <tex-math notation="LaTeX">Q </tex-math></inline-formula>-factor of 58 at 5.6 GHz and a self-resonant frequency of 19 GHz. The best inductance density of 63 nH/mm 2 is reached by an eight-turn 9.5-nH solenoid.