Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 27: Poster Session I

MM 27.29: Poster

Tuesday, March 13, 2018, 18:30–19:45, Poster E

Miniaturisation of reactively wetting SnPb micro-solder on Cu and Ni capillary tracks — •Samuel Griffiths, Patcharawee Jantimapornkij, and Guido Schmitz — Institute of Materials Science, Stuttgart, Germany

Micro-solder technologies are ubiquitous in modern electronics industries. And although these industries have pushed practical advancements in solder technologies, little is understood about the flow kinetics and thermodynamic theory which predicts solder flow behavior. Quantification and analyses of the capillary flow behavior of eutectic Sn-Pb micro-solder on microstructured linear Ni and Cu conductive tracks is presented for multiple track widths. Solder-flow experiments have been conducted at 350°C in a reducing flux environment, resulting in reactive wetting. Parameters such as the equilibrium solder-flow distance, wetting/contour angles, and conductive track width are quantitatively linked. It is shown that, the relationship between the equilibrium solder-flow distance and track width behaves inversely for the Ni and Cu conductive tracks. Additionally, traditional contact angle control measurements are used to draw comparisons with the equilibrium angles of the solder fronts, which are the only dimensionally unrestricted wetting angles of the solder-flow experiments. Electron microscopic imaging and chemical analysis as well as theoretical modelling based on surface energy minimization are applied to support our conclusions.