Uncovering the driving force for massive spalling in the Sn–Cu/Ni system
Received 2 February 2010; received in revised form 2 March 2010; accepted 2 March 2010. published online 08 March 2010.
To identify the driving force for the massive spalling phenomenon, carefully designed experiments were carried out. Cu-doped Sn-rich solder was reacted with Ni to form first the Sn–0.6Cu/(Cu,Ni)6Sn5/Ni structure. The original Sn–0.6Cu solder was then removed and replaced with Sn–0.3Cu or with fresh Sn–0.6Cu. Swapping the solder to Sn–0.3Cu caused massive spalling of (Cu,Ni)6Sn5. The results of this study unequivocally prove that the massive spalling reported in the literature is caused by a driving force that is purely thermodynamic in nature.
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