Effects of aging on interfacial microstructure and reliability between SnAgCu solder and FeNi/Cu UBM

Qing Sheng Zhu, Jian Jun Guo, Pan Ju Shang, Zhong Guang Wang, Jian Ku Shang

Research output: Contribution to journalArticle

Abstract

Effects of thermal aging on the interfacial microstructure and reliability of the SnAgCu/FeNi-Cu joint are investigated. It is found that aging effects depends strongly on the temperature. Aging at low temperature, e.g., at 125 °C, a submicron meter thick FeSn2 IMC layer formed at the SnAgCu/FeNi-Cu interface during reflowing grows at a rate twenty times slower than the growth rate of the IMC at the SnAgCu/Cu interface. At high temperature, e.g., at 180 °C, the Cu element is found to diffuse through FeNi layer to produce the (Cu, Ni)6Sn5 IMC and this IMC layer grows even faster than the IMC at the SnAgCu/Cu interface. Solder ball shear test results show that the SnAgCu/FeNi-Cu joint has a comparable strength to the SnAgCu/Cu joint after reflowing, and the strength drop after aging at 125 °C is less than that of the SnAgCu/Cu joint. However, after aging at 180 °C, the strength of the SnAgCu/FeNi-Cu joint is degraded to a low value, along with a shift in failure mode from the solder fracture to the brittle intermetallics fracture.

Original languageEnglish (US)
Pages (from-to)497-503
Number of pages7
JournalAdvanced Engineering Materials
Volume12
Issue number6
DOIs
StatePublished - Jun 1 2010

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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