Mosaic near-infrared focal plane array

Takashi Ichikawa, Nobunari Itoh, Kenshi Yanagisawa, Ken'ichiro Asai, Tadashi Shiraishi, Masafumi Kimata

Research output: Contribution to journalConference articlepeer-review


To built a 3K X 3K pixel near-IR FPA, we have made a package and a multi-chip module for Mitsubishi 1040 X 1040 PtSi CSD, which is one of the largest SWIR FPAs. Mosaicing demands smallest gaps between chips to achieve a large fill-factor and controlled flatness to fit a camera focal plane. The package of 52-pin half-pitch PGA has been designed to be smaller than the bear chip. After the chip is glued on the package and wire-bonded, nine packages with the chip are arrayed in three by three on a multi chip module (MCM) of 6 cm X 6 cm area. The fill-factor of the imaging area is 89 percent. The package and MCM are made of AlN ceramic of high thermal conductivity. MCM, therefore, plays a role of an efficient heat sink. The surface of the package, with which the chip is in contact, has been polished with accurate flatness as well as MCM. As the result, the height of nine chips built on MCM are uniform within approximately 20 micrometers in 6 cm X 6 cm area. The mosaic array will be equipped in a near-IR camera for astronomical observations of a wide field view.

Original languageEnglish
Pages (from-to)313-316
Number of pages4
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1998 Dec 1
EventInfrared Astronomical Instrumentation - Kona, HI, United States
Duration: 1998 Mar 231998 Mar 23


  • CSP
  • MCM
  • Mosaic FPA
  • PtSi CSD
  • SWIR

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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