Effects of zinc on the interfacial reactions of tin-indium solder joints with copper

Shih Kang Lin, Ru Bo Chang, Sinn Wen Chen, Ming Yueh Tsai, Chia Ming Hsu

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Sn-20.0 wt%In (Sn-20.0In) alloy is a promising base material in Pb-free solders for low-temperature applications. Zn is often used as an additive to Pb-free solders to reduce the extent of undercooling during reflow. Cu is the most commonly used substrate in electronics industry. Interfacial stability at Sn-In-Zn/Cu joints is crucial to reliability of electronic products. In this study, interfacial reactions between Sn-20.0 wt%In-x wt%Zn (Sn-20.0In-xZn) solders and Cu where x = 0.5, 0.7, 1.0, 2.0, 3.0, and 5.0 at 150, 230, and 260 C were experimentally examined. It is found that the reaction phase formation and interfacial morphologies are strongly influenced by Zn concentrations. The reaction phases evolve from the Cu6Sn5 phase, CuZn and Cu5Zn8 phase, to Cu5Zn8 phase with higher Zn doping in the solders. The Cu5Zn8 phase acted as a diffusion barrier and suppressed the growth of the Cu6Sn 5 phase. The results indicate that 2.0 wt%Zn addition resulted in the gentlest reactions during both soldering and solid-state ageing in Sn-20.0In-xZn/Cu couples.

Original languageEnglish
Pages (from-to)3805-3815
Number of pages11
JournalJournal of Materials Science
Issue number10
Publication statusPublished - 2014 May

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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