Adhesive flip chip bonding in a miniaturised spectrometer

This paper discusses the selection of a suitable isotropically conductive adhesive for flip chip bonding of a micromachined component. The adhesive must have adequate electrical conductivity and mechanical bonding strength. Most commercial adhesives possess these qualities. In addition, small bumps of spherical shape need to be dispensed evenly and repeatedly. Eight adhesives were studied and one suitable candidate was found. The manufacture of the spectrometers proceeded successfully. The interferometer was fixed on top of a silicon detector by a flip chip technique using an isotropically conductive adhesive. Two prototype series with a total of 25 spectrometers have been produced, and 23 of them passed operational testing.