Study on the patterning and annealing effect of planar inductors with composite ferromagnetic films has been presented in this article. The magnetic films (MFs) are deposited on the same coil structure and then followed by an annealing process in vacuum. Two equivalent circuits are proposed to analyze the modification of inductor performance. The patterned inductors exhibit higher quality factor without much decrease of inductance compared with the nonpatterned one. The square-type inductor shows the highest peak value of quality factor (16.01 at 1.15 GHz) because of the finest MF division. After annealing, both the inductance and quality factor of the four types of inductors are increased, and the nonpatterned inductor shows the largest increment of inductance. (C) 2008 American Vacuum Society.