A power inductor component is relatively very thick and large shape. Therefore, these components are not appropriate feature to be embedded into a LSI package and mounted nearby a LSI chip, it is challengeable to make the embedded application. However, LSI power delivery system is going for low voltage and large current, and losses between power supply and loads impacts on the power supply efficiency characteristic. In order to solve this problem, miniaturization for a power inductor is needed to realize the embedded applications.
As one of approaches to realize the power delivery systems, the planar power inductor with Zn-Ferrite film has been studied for the next generations. A structure of planar power inductor was designed to be configured 2-turn inner copper spiral coil covered with top and bottom magnetic core. The Zn-Ferrite film used as a magnetic core has a high resonance frequency around 300MHz and high saturation magnetization of 0.6T or more, and this film can be formed in low temperature, which can be handled in parallel way to fabricate an organic package.
We have developed the organic package with employing the power inductors covered with Zn-Ferrite as prototype of the embedded application, and evaluated the electrical and magnetic characterizations.
The thickness of embedded planar power inductor covered with Zn-ferrite film is 50um, and the size is 850um squares. Q factor is 10 to 13 in 30MHz to 100MHz. The degradation of inductance caused by the superimposed current does not happen without changing until 3A.
Fabrication of a Mn-Zn Ferrite Particle/Polyimide Composite Thick Film for Transmission-Line Devices.
