Influence of Element Lead (Pb) Content in Tin Plating on Tin Whisker Initiation/Growth

The implementation of the Restriction Hazardous Substances (RoHS) European Union (EU) Directive in 2005 resulted introduction pure tin as an acceptable surface finish for printed circuit boards and component terminations. A drawback finishes is potential to form whiskers. Tin whiskers are a metallurgical phenomenon that associated with rich/pure materials has been topic intense industry interest. acceptance usage by electronics fabricators understandable inexpensive, simple plating systems operate have reasonable solderability characteristics. However, high performance/harsh environment typically product life cycles measured decades therefore much more susceptible long term threat GEIA-STD-0005-2 “Standard Mitigating Effects Whiskers Aerospace High Performance Electronic Systems” established definition “Pb-free tin” : defined be or any alloy <3% lead (Pb) content weight. functional “pure was necessary so could establish whisker risk protocols against known target value terms soldering processes. An investigation conducted determine influence 1% - 5% elemental on initiation growth. results were used revision specification technical discussions.