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

• Published in: IEEE transactions on electron devices Vol. 69; no. 9; pp. 5116 - 5122
• Main Authors: Zhang, Weihao, Zhou, Guoyun, Gao, Qi, Jia, Wei, Chen, Xianming, Huang, Benxia, Feng, Lei, He, Wei, Wang, Chong, Zhu, Yongkang
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Inductance; Inductors; Integrated inductor; lithographic via technology; Magnetic cores; organic packaging substrate; Packaging; power supply module integration; Q-factor; Saturation magnetization; Soft magnetic materials; Solenoids; Substrates
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2022.3188592

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 <inline-formula> <tex-math notation="LaTeX">\text{m}\Omega </tex-math></inline-formula>, 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/<inline-formula> <tex-math notation="LaTeX">\text{m}\Omega </tex-math></inline-formula>. Therefore, the proposed inductor achieves a superior <inline-formula> <tex-math notation="LaTeX">{Q} </tex-math></inline-formula>-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.