RF circuit design aspects of spiral inductors on silicon

In this experiment, the substrate silicon is removed using micromachining techniques, and the remaining thin-film structure is bonded onto a quartz substrate. The micromachined inductor has Q/sub MAX//spl ap/60 at 6 GHz. The lower resistivity and the greater conductor thickness of copper (Cu) compared to the aluminum (Al) process leads to a 3-4/spl times/ increased Q/sub MAX/ over the entire range of feasible inductance values.