Journal of Failure Analysis and Prevention

, Volume 13, Issue 2, pp 194–201 | Cite as

Failure Analysis of Un-Wetting for the Surface Finish on the ENIG

  • Shi Yan
  • Fei-Jun Chen
  • Yue-Yue Ma
  • Zhen-Guo Yang
Technical Article---Peer-Reviewed


Electroless nickel immersion gold (ENIG) is one of the most prevailing surface finishes for printed circuit board. It is widely adopted by manufacturers all over the world for its relative low price and compliance with the trend of high density packaging. However, its reliability is always of a concern. In this paper, the poor wetting performance of tin solder on the ENIG surface, which is one of its reliability issues was addressed. A series of modern facilities were utilized for finding the failure mechanism and chasing down the root cause. It was concluded that the inferior quality of immersion gold layer during plating, to be more specifically, the coarse and big grain size and the crystalline interface cracking were the main causes for the un-wetting failure. Last but not least, the improper choice of pure tin solder should also contribute to the final failure.


ENIG Un-wetting Grain size Failure analysis Oxidation 


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Copyright information

© ASM International 2013

Authors and Affiliations

  • Shi Yan
    • 1
  • Fei-Jun Chen
    • 1
  • Yue-Yue Ma
    • 1
  • Zhen-Guo Yang
    • 1
  1. 1.Department of Materials ScienceFudan UniversityShanghaiChina

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