Embedded Magnetic Solenoid Inductor Into Organic Packaging Substrate Using Lithographic Via Technology for Power Supply Module Integration

In this article, an embedded magnetic solenoid inductor into an organic packaging substrate is implemented based on lithographically defined vias with a semiadditive process flow. In this solenoid inductor, the solid vertical interconnects and magnetic composite core are simultaneously utilized, both significantly reducing dc resistance and boosting inductance per unit area. A small-signal electrical test of the microinductor shows greatly improved performance including a flat dc inductance of 41.9 nH, low dc resistance of 60
$\text{m}\Omega $
, a peak quality of 42.7 at 92.8 MHz, and a high 10% saturation current of 3.81 A with a footprint area of 5.7 mm
²
. Consequently, the microinductor fabricated achieves a high inductance to resistance ratio of 0.7 nH/
$\text{m}\Omega $
. Therefore, the proposed inductor achieves a superior
${Q}$
-factor of 42.7 that is the highest reported value for a solenoid magnetic power inductor with this prior art. The calculated peak effective inductor efficiency is 98.11% for 3.6- to 1-V, 100-MHz dc–dc conversion.