Modeling of the underfill flow process in the flip chip bonded pixel detectors

Akiko Gädda, Jaakko Salonen, Sami Vähänen, Philippe Monnoyer, Hannele Heikkinen, Harri Pohjonen, Simo Eränen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review


Modeling of the underfilling process of the flip chip bonded components has been studied. The size of the hybridized pixel detectors used in the flip chip bonding process varied up to 1 cm * 1.6 cm. An underfill was required to enhance the mechanical properties of the bonded component. An imidazole based epoxy resin was used as the underfill polymer. Computational methods were considered to be highly attractive in order to reduce failure in testing of limited number of available experimental samples. In addition, the computational methods permit rapid definition of suitable process parameters. The polymer was modeled as a non-Newtonian fluid, which agreed with the actual material properties. The modeling was also selected as simple as possible. The obtained values were replicated as close as possible during the actual dispensing of the underfill material. The viscosity of the underfill material was adjusted by heating. The modeled parameters were validated by positive results on the bonded components.
Original languageEnglish
Title of host publicationProceedings
Subtitle of host publicationIMAPS Nordic Conference 2012
EditorsJarkko Kutilainen
PublisherIMAPS Nordic
ISBN (Print)978-1-6227-6316-0
Publication statusPublished - 2012
MoE publication typeA4 Article in a conference publication
EventIMAPS Nordic Annual Conference 2012 - Helsingor, Denmark
Duration: 2 Sept 20124 Sept 2012


ConferenceIMAPS Nordic Annual Conference 2012


  • Flip chip bonding
  • Modeling
  • Non-Newtonian flow
  • Pixel detector
  • Underfill


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