Technical Paper

Microsystem Technologies

, Volume 14, Issue 7, pp 903-907

First online:

Design and fabrication of the suspended high-Q spiral inductors with X-beams

  • M. C. HsiehAffiliated withDepartment of Electronic Engineering, Kun Shan University Email author 
  • , D. K. JairAffiliated withDepartment of Mechanical Engineering, Kun Shan University
  • , C. S. LinAffiliated withDepartment of Electronic Engineering, Fortune Institute of Technology

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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 4,500 times. Among these structures, the measured maximum quality factor (Q) of the suspending inductor and frequency at maximum Q are improved from 5.2 and 1.6 GHz of conventional spiral inductor to 7.3 and 2.1 GHz, respectively.