Thin Film Inductor with Multilayer Magnetic Core.

In this paper, thin film micro inductor was investigated from the stand point of increased quality factor (Q) and inductance (L). To obtain a high Q, it is important to use a magnetic core in which iron loss is small in high frequency. The thin micro film inductor was prepared using multi-layered CoNbZr/ AIN film. The best condition for high Q was investigated by changing the size of magnetic core and structure of multilayer and exciting coil. The Q and L are increased with decreasing thickness of one magnetic layer and increasing one interlayer. The demagnetization of open magnetic circuit of inductor is decreased by using multi-layered magnetic core. The stray capacitance between coil and magnetic core is dominant in these thin film inductors. It was found that multi-layered magnetic core is useful to increase the Q value and L of thin film inductors in high frequency. The experimental inductor in which iron and copper loss are decreased by multi-layered core and thick coil shows L= 120 nH, Q= 18 at 50 MHz in its size of 0.5 mm×2.5 mm×35μm