A CMOS-compatible MEMS integrated on-chip inductor is designed. The square planar spiral coil program is utilized. The coils are made of copper with a higher conductivity than aluminum. In order to improve the quality factor (Q) of the inductor, thick metal coils and cavities etched in the CMOS-grade silicon substrate are designed by the MEMS technology, which can reduce the serial resistance of metal square planar spiral coils and the losses in the low resistance silicon substrate, respectively. A fully CMOS-compatible low temperature MEMS process is presented and a 1nH inductor model with thick metal coils and low-loss MEMS substrate is simulated by using HFSS software. Simulation results show that the inductor obtained by this CMOS-compatible low temperature MEMS process enjoys a high peak quality factor of 22.37 and 20.74 at 6.6GHz and 10GHz with a self-resonant frequency over 20GHz, respectively. The influences of metal coils' thickness on the quality factor and the inductance are also analyzed. When the thickness of the inductor is increased, the quality factor is increased while the inductance is decreased. The fluctuation of the inductance is less than 5.5% in the simulation frequency range.