Assessment of Solder-Dipping as a Tin Whisker Mitigation Strategy

Tin whiskers have been brought back into the spotlight due to the transition of the electronics industry to lead-free solders. Many different tin whisker failure mitigation strategies are being evaluated by researchers. This paper investigates the technique of solder-dipping as a tin whisker mitigation strategy for tin-based lead-free finished surfaces used in electronic products. Tin finished Alloy 42 lead-frame parts are subjected to the solder-dip process. For this paper, the solders included eutectic tin-lead and tin-silver-copper. In addition, tin-bismuth (Sn-Bi) finished alloy 42 lead-frame parts are also examined to assess the effectiveness of the Sn-Bi finish in mitigating tin whisker growth. Parts under study are subjected to temperature cycling conditions to promote whisker formation. It is observed that whiskers are formed on all treatment surfaces, with the longest whiskers occurring on the pure tin-finished parts. The solder-dipped parts showed better mitigation of tin whiskers than the pure tin-finished parts.

[1]  G. Wilcox,et al.  Observations of the spontaneous growth of tin whiskers on tin-manganese alloy electrodeposits. , 2005, Physical review letters.

[2]  M. Dittes,et al.  Tin Whisker formation - results, test methods and countermeasures , 2003, 53rd Electronic Components and Technology Conference, 2003. Proceedings..

[3]  S. Lal,et al.  Role of intrinsic stresses in the phenomena of tin whiskers in electrical connectors , 2005, IEEE Transactions on Electronics Packaging Manufacturing.

[4]  R. Schetty.  Electrodeposited tin properties & their effect on component finish reliability , 2004, Proceedings of 2004 International Conference on the Business of Electronic Product Reliability and Liability (IEEE Cat. No.04EX809).

[5]  K. S. Kim,et al.  Tin whisker formation of lead-free plated leadframes , 2006, Microelectron. Reliab..

[6]  Hsiu-Jen Lin,et al.  Rapid growth of tin whiskers on the surface of Sn–6.6Lu alloy , 2007 .

[7]  Qiang Yu,et al.  Tin Whiskers: How to Mitigate and Manage the Risks , 2007, 2007 International Symposium on High Density packaging and Microsystem Integration.

[8]  Chen, Xu,et al.  Driving force for the formation of Sn whiskers: compressive stress-pathways for its generation and remedies for its elimination and minimization , 2005, IEEE Transactions on Electronics Packaging Manufacturing.

[9]  Jay Brusse,et al.  The Continuing Dangers of Tin Whiskers and Attempts to Control Them with Conformal Coating , 2001 .

[10]  S. Rajagopal,et al.  The impact of lead-free legislation exemptions on the electronics industry , 2004, IEEE Transactions on Electronics Packaging Manufacturing.

[11]  Michael Osterman,et al.  Examination of nickel underlayer as a tin whisker mitigator , 2009, 2009 59th Electronic Components and Technology Conference.

[12]  M. Osterman,et al.  The Effect of Annealing on Tin Whisker Growth , 2006, IEEE Transactions on Electronics Packaging Manufacturing.

[13]  K. Whitlaw,et al.  Preventing whiskers in electrodeposited tin for semiconductor lead frame applications , 2004 .

[14]  I. Pulford.  Waste Electrical and Electronic Equipment (WEEE) , 2013 .

[15]  K. Suganuma,et al.  Suppression of tin whisker formation on fine pitch connectors by surface roughening , 2006 .