Abstract
The present study investigates the dynamic surface tension of molten 63%Sn–37%Pb eutectic solder at timescales 1–3 ms applicable to solder jetting applications in microelectronics manufacturing. The oscillating jet method is employed to measure the surface tension of the melt when ejected into nitrogen atmospheres containing controlled amounts of oxygen from 15 ppm to 21% (mol). Typical jet ejection conditions correspond to We=0.16, Re=49, and Fr=165. The molten solder is steadily forced through an elliptical capillary (aspect ratio of ∼2), thus forming a stationary oscillating jet. The shape evolution of the jet is affected by the liquid/gas interface properties and is used, along with an existing theoretical model, to determine the surface tension of the liquid metal as a function of distance (likewise, surface age) from the orifice. The experimental data reveals dynamic surface tension behavior at 3700 ppm O 2 concentration, and indicates a characteristic time below 1 ms for the molten-metal surface to be saturated by adsorbed oxygen at ambient O 2 concentrations of 1% or higher. Mass diffusion in the gas phase is found to be the rate limiting process controlling oxygen adsorption on the solder melt surface. The results provide crucial information needed to reduce solder surface degradation, which hampers the successful implementation of solder jetting technology.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
