Integrated solenoid-type inductors for high frequency applications and their characteristics

Young Jun Kim, M. G. Allen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

18 Citations (Scopus)


New solenoid-type integrated inductors for high frequency applications have been realized using a surface micromachining technique and a polymer sacrificial layer, and their geometrical characteristics have been investigated. In general, integrated inductors can suffer from low Q factors and/or self-resonant frequencies when compared to their discrete counterparts. A spiral-type inductor, one of the dominant choices as an integrated inductor, requires relatively large two-dimensional spaces. In addition, the direction of flux of the spiral type inductor is perpendicular to the substrate, which can cause more interference with underlying circuitry or other integrated passives in a vertically stacked multi-chip module (MCM). The proposed inductor in this research has an air core to reduce unwanted stray capacitance that can be added due to a magnetic core, and electroplated copper coil to reduce the series resistance. An important feature of the proposed inductor geometry is introducing an air gap between the substrate and the conductor coil in order to reduce the effects of the substrate dielectric constant. This air gap can be realized using a polyimide sacrificial layer and a surface micromachining technique. Therefore, the resulting inductor can have less substrate-dependent magnetic properties, less stray capacitance, and higher Q-factor. Inductors with different geometrical aspects, such as air gap height, core size, and number of turns, have been designed and fabricated on ceramic substrates. A variational study of these inductors has been performed to assess the impact of the geometrical aspects on the inductor performance at high frequency. The measured inductance of these inductors varies from 2nH to 20 nH, and maximum Q-factor 10-60.

Original languageEnglish
Title of host publication1998 Proceedings - 48th Electronic Components and Technology Conference, ECTC 1998
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Print)0780345266
Publication statusPublished - 1998
Event48th Electronic Components and Technology Conference, ECTC 1998 - Seattle, United States
Duration: 1998 May 251998 May 28

Publication series

NameProceedings - Electronic Components and Technology Conference
VolumePart F133492
ISSN (Print)0569-5503


Conference48th Electronic Components and Technology Conference, ECTC 1998
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 1998 IEEE.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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