Fabrication of solenoid-type inductor with electroplated NiFe magnetic core

Solenoid-type inductor with ultra-low profile was fabricated by MEMS (Microelectromechanical systems) technique. NiFe film was electroplated as the magnetic core, and polyimide with a low relative permittivity was used as the insulation material. In the fabrication process, UV-LIGA, dry etching, fine polishing and electroplating technique have been adopted to achieve high performance of the solenoid-type inductor. The inductor was in size of 1.5 mm×0.9 mm×0.1 mm with coil width of 20 μm and aspect ratio of 5:1. The inductance and the quality factor were 0.42–0.345 μH and 1.8–5.3 in the frequency range of 1–10 MHz, respectively.