Rheological Characterisation and Empirical Modelling of Lead-Free Solder Pastes and Isotropic Conductive Adhesive Pastes

    Volume 7, Issue 7 (July 2010)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 29 July 2010

    Page Count: 13


    Durairaj, R.
    Dept. of Mechanical and Material Engineering, Faculty of Engineering and Science (FES), Univ. Tunku Abdul Rahman (UTAR), Kuala Lumpur,

    Man, Lam Wai
    Dept. of Mechanical and Material Engineering, Faculty of Engineering and Science (FES), Univ. Tunku Abdul Rahman (UTAR), Kuala Lumpur,

    Ramesh, S.
    Dept. of Mechanical and Material Engineering, Faculty of Engineering and Science (FES), Univ. Tunku Abdul Rahman (UTAR), Kuala Lumpur,

    (Received 30 January 2010; accepted 17 June 2010)

    Abstract

    Solder pastes and isotropic conductive adhesives (ICAs) are widely used as an interconnect in the electronic industry. Paste printing process accounts for majority of the assembly defects in the electronic manufacturing industry. This study investigates the effect of shear rates on the viscosities of the pastes (solder pastes and ICAs) used for flip chip assembly. Empirical models such as the power law and the Cross model were used to quantify the viscosity over a range of shear rates for solder pastes and fit to the experimental data. The shear rate dependence viscosity of solder pastes could be used to study the flow behavior experienced by the pastes during the stencil printing process. From the results, viscosities of all three types of pastes were said to be dependence on shear rate. In a stencil printing process, as if the viscosity of the solder paste was too high, the paste might not wet the surface of the substrate and more energy was needed to force the paste penetrate the aperture. This study has revealed that the fitting of the Cross model is generally of better quality than the power law model because the qualitative behavior of the Cross model throughout the whole range of shear rates (0.001 s−1 to 100 s−1) is essentially the same as the experimental data.


    Paper ID: JAI103009

    DOI: 10.1520/JAI103009

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    Author
    Title Rheological Characterisation and Empirical Modelling of Lead-Free Solder Pastes and Isotropic Conductive Adhesive Pastes
    Symposium , 0000-00-00
    Committee D02