Authored By:
Jim Kenny, Nils Arendt, Bernhard Wessling, Karl Wengenroth
Enthone Inc., A Business of Cookson Electronics
West Haven, CT, USA
Summary
With the international implementation of lead-free technologies/processes use of Immersion Tin usage as a PWB final finish is expected to grow substantially in the near future. With the world-wide growing demand for Immersion Tin, the demands towards the product and process technology consequently increase significantly. Market leading OEMs require the surface finish to have higher tin thickness, improved solderability at multiple heat cycles and higher temperatures, perfect surface flatness, fine pitch compatibility, etc. Modern Immersion Tin technology can serve such requirements and has proven over several years its superior product and process advantages at market leading PCB manufacturers.
New technology using unique Organic Metal technology in the immersion tin process allows for thinner tin coatings without sacrificing performance. The catalyst and passivation effect of the Organic Metal leads to a large grain size with a low affinity for oxidation or whiskers and high process reliability. The ability of a thin immersion tin to achieve comparable performance to thick immersion tin results in significant improvements in process costs, yields and environmental impact
Conclusions
The use of Organic Metals in the immersion tin process have many benefits. These benefits include enhanced tin grain structure, copper passivation, uniform plating initiation for excellent plating distribution. By incorporating Organic Metals into a post dip, improvements can be made in cycle time, operating costs, labor costs, equipment costs, floor space, product reliability and quality. Thin immersion tin coatings generated with Organic Metals are more efficient and produce the same reliability as thick immersion tin
Initially Published in the SMTA Proceedings
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