High Q-factor inductors integrated on MCM Si substrates

High quality factor (Q) inductors were designed and fabricated on high-resistivity (2000 /spl Omega//spl middot/cm) Si substrates with multichip module (MCM) fabrication technology. A Q-factor of 30 was achieved for an inductor of 4 nH at 1-2 GHz. To enhance the Q-factor and reduce the parasitic coupling capacitance, a staggered double metal-layered structure was utilized by taking advantage of the double-layered metal lines in MCM. With electromagnetic simulation tools, computer-aided analysis was used to optimize the device characteristics. The skin effect and the lossy substrate effect on the performance of the radio frequency (RF) thin-film inductors were studied. The fabrication process used polyimide as the dielectric layer and aluminum as the metal layer. The use of the low dielectric-constant material, polyimide, reduces the parasitic coupling capacitance between metal lines and increases the quality factor and the self-resonant frequency for the RF integrated inductors.