Fabrication of indium bumps for hybrid infrared focal plane array applications

Jutao Jiang, Stanley Tsao, Thomas O'Sullivan, Manijeh Razeghi*, Gail J. Brown

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


Hybrid infrared focal plane arrays (FPAs) have found many applications. In hybrid IR FPAs, FPA and Si read out integrated circuits (ROICs) are bonded together with indium bumps by flip-chip bonding. Taller and higher uniformity indium bumps are always being pursued in FPA fabrication. In this paper, two indium bump fabrication processes based on evaporation and electroplating techniques are developed. Issues related to each fabrication technique are addressed in detail. The evaporation technique is based on a unique positive lithography process. The electroplating method achieves taller indium bumps with a high aspect ratio by a unique "multi-stack" technique. This technique could potentially benefit the fabrication of multi-color FPAs. Finally, a proposed low-cost indium bump fabrication technique, the "bump transfer", is given as a future technology for hybrid IR FPA fabrication.

Original languageEnglish (US)
Pages (from-to)143-151
Number of pages9
JournalInfrared Physics and Technology
Issue number2
StatePublished - Mar 2004


  • Bump
  • Electroplating
  • Evaporation
  • Focal plane array
  • Indium
  • Infrared
  • Lift-off

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics


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