Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration IZM

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  • Publication
    Advanced mixed-mode bending test: A rapid, inexpensive and accurate method for fracture-mechanical interface characterisation
    ( 2012)
    Wunderle, B.
    ;
    Schulz, M.
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    Keller, J.
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    May, D.
    ;
    Maus, I.
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    Pape, H.
    ;
    Michel, B.
    This paper presents a comprehensive method for obtaining urgently required critical interface delamination data of material pairings used in electronic packaging. The objective is to thereby enable rapid, inexpensive and accurate lifetime prediction for that failure mode. A new testing method is presented which allows maximum mode-angle range and enhanced throughput testing under multiple loading conditions, the coverage of which is usually a rather lengthy and resource-demanding procedure. The approach is specimen-centred in the sense that the accent is put on test-specimens which are easily manufacturable industrially, rather than having to adapt them to a special testing machine. The concept is also scalable, i.e. it has potential to work also for smaller samples cut from real devices. We show the first version of a newly developed test-stand and discuss the obtained results for copper-molding compound interfaces in the light of the current state of the art used for delamination testing in electronic packaging.
  • Publication
    In-situ measurement of various thin bond-line-thickness thermal interface materials with correlation to structural features
    ( 2008)
    Wunderle, B.
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    Kleff, J.
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    Mrossko, R.
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    Abo Ras, M.
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    May, D.
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    Schacht, R.
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    Oppermann, H.
    ;
    Keller, J.
    ;
    Michel, B.
    Thermal characterisation of thermal interfaces becomes even tougher a challenge at low bond line thicknesses and higher thermal conductivities of the interface materials as more accurate measurement techniques are required. As in parallel the quest for high conductivity adhesives and greases is ongoing, a correlation between thermal bulk or interface properties and structure is in high demand. We have developed test-stands for various classes of thermal interface materials. These permit characterisation for materials with thin bond line thickness and high thermal conductivity still using steady state techniques. The methods are benchmarked for greases, adhesives and sintered silver. For the latter, the technology development is described. Then, structural features such as particle density and porosity are examined. It will be the aim to compare and correlate them to thermal resistance. Part of the work has been accomplished within the running EU. Project "Nanopack".