Here is the abstract you requested from the nano_2013 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Waferbumping Fluxes Enabling 2.5D and 3D Technology|
|Keywords: Flux, Copper pillar / microbump, 2D / 3D|
|Spin-coating is used to coat semiconductor wafers with radically different materials: from photoresists (used in semiconductor fabrication) to bump fusion fluxes (used in semiconductor assembly). Bump fusion (or “waferbumping” fluxes) are widely used to produce oxide-free coplanar solder microbumps after a copper pillar / solder plating process. In this paper the spin coating process for these fluxes is examined both theoretically and experimentally. A mathematical model has been developed for a flux spin-coating process based on both material and process variables, the results of which are then compared experimentally with data. The theoretical analysis of a spin coating process is physically and mathematically complex but nevertheless even partial analysis provides insight into the effectiveness and limitations of the process. Variables studied include viscosity, initial dispensed volume, rotational speed, and time. In conclusion, a discussion of the model; its comparison with real-life situations; and pragmatic considerations for waferbumping flux usage (including reflow profiles, varying spin-speeds and “dam and fill” strategies are considered).|
|Andy C Mackie, PhD, Senior Product Manager