Silicon-on-Organic Integration of a 2.4–GHz VCO Using High-Q Copper Inductors and Solder-Bumped Flip Chip Technology

High-Q copper inductors were fabricated on low-cost and low-loss bismaleimide triazine (BT) and glass substrate using electroplating process. A differential
LC
voltage-controlled oscillator (VCO) circuit was designed using these high-Q inductors at 2.4 GHz. Flip chip and multichip module (MCM) technologies were applied to assemble the active chips on BT and glass substrate. The inductors exhibited Q-factor as high as 25 at 2.4 GHz. VCOs with copper inductors on BT and glass substrate had phase noise of -108 dBc/Hz at 600 kHz offset for a 2.4-GHz carrier, which is 6-dB improvement compared with the one with on-chip Al inductors. There was almost no substrate loss for inductors on BT and glass substrates. The effect of fabrication defects and solder joint resistance were also investigated. This technique can be extended to other building blocks, thus realizing integration of the whole RF system.