Monolithic fabrication of electroplated solenoid inductors using three-dimensional photolithography of a thick photoresist

Jun Bo Yoon, Chul Hi Han, Euisik Yoon, Choong Ki Kim

Research output: Contribution to journalArticle

43 Citations (Scopus)


A novel and high-yield fabrication process has been devised for monolithic integration of solenoid inductors. In order to simplify the fabrication steps, we decompose the solenoid inductor into two parts, bottom conductor lines and air bridges. The air bridge is formed as a single body during a single electroplating step. This single-step fabrication of the air bridges is possible by forming a three-dimensional (3D) photoresist mold using multiple exposures with varying exposure depths, followed by a single development step, which realizes the 3D latent image of the unexposed volume in the photoresist. We have successfully fabricated solenoid inductors with and without a magnetic core using this process. This process is easy and simple, so that one can significantly improve the fabrication yield over that achieved by conventional methods. Also, this process has good compatibility with the integrated circuit (IC) process owing to a low process temperature (< 120°C) and the monolithic feature.

Original languageEnglish
Pages (from-to)7081-7085
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number12 B
Publication statusPublished - 1998 Dec 1


All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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