In this paper, deep sub-micron CMOS process compatible high Q on chip spiral inductors with air gap structure were designed and fabricated. In the design the electromagnetic solver, SONNET, and the finite element program, ANSYS, were used for electrical-characteristics and maximum mechanical strength, respectively. The copper wires were capped with electroless Ni plating to prevent the copper from oxidizing. A Si3N4/ SiO2 X-beam was designed to increase the mechanical strength of the inductor in air gap. The enhancement of maximum mechanical strength of a spiral inductor with X-beams is more than 4500 times. Among these structures, the measured maximum quality factor (Q) of the suspending inductor and frequency at
M. C. Hsieh, D. K. Jair, Y. K. Fang, C. S. Lin