Advanced Viscoelastic Material Model for Predicting Warpage of a QFN Panel

J de Vreugd, KMB Jansen, A Xiao, LJ Ernst, C Bohm, A Kessler, H Preu, M Stecher

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientific

27 Citations (Scopus)


Warpage is a critical issue for a QFN panel molding process. Much work was done in the past to predict the warpage of a package during cooling down from molding temperature. However, until now, warpage could not always be predicted well, even if the viscoelastic behavior of the molding compound is taken into account. It was for example observed that the cooling velocity affected the warpage after cooling down. Because of this reason, the mechanical behavior of the molding compound was investigated in more detail. In this research, the mechanical properties of the molding compound are determined. It turned out that the properties are highly dependent on time and temperature. A complete viscoelastic model of the model compound is achieved by combining DMA and dilatometric test results. The model is implemented in the finite element software ABAQUS. In this study, our advanced model is compared with elastic calculations which are normally done. A validation experiment is performed in which simulation results are compared with experimental warpage data of a double layered beam, consisting of a layer of molding compound and a layer of silicon. This beam is cooled down from a temperature above Tg to room temperature with different cooling rates. In the meantime warpage is measured and compared to simulation results. Finally, the advanced material model is used for calculations on a QFN-panel.
Original languageUndefined/Unknown
Title of host publication2008 Proceedings 58th Electronic Components & Technology Conference, Lake Buena Vista, FL, USA
Editors Wipiejewski, T., Trewhella, J.
Place of PublicationOrlando, FL, USA
Number of pages6
ISBN (Print)978-1-4244-2231-9
Publication statusPublished - 2008
Event58th Electronic Components & Technology Conference, Lake Buena Vista, FL, USA - Orlando, FL, USA
Duration: 27 May 200830 May 2008

Publication series



Conference58th Electronic Components & Technology Conference, Lake Buena Vista, FL, USA


  • conference contrib. refereed
  • Conf.proc. > 3 pag

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