• A study aimed at characterizing the interfacial structure in a tin–silver solder on nickel-coated copper plate during aging

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      https://www.ias.ac.in/article/fulltext/sadh/033/03/0251-0259

    • Keywords

       

      Interconnections; printed circuit board; electronic packaging; solder bumps; thermal aging performance.

    • Abstract

       

      This paper highlights the interfacial structure of tin-silver (Sn-3·5Ag) solder on nickel-coated copper pads during aging performance studies at a temperature of 150°C for up to 96 h. Experimental results revealed the as-solidified solder bump made from using the lead-free solder (Sn-3·5Ag) exhibited or showed a thin layer of the tin–nickel–copper intermetallic compound (IMC) at the solder/substrate interface. This includes a sub-layer having a planar structure immediately adjacent to the Ni-coating and a blocky structure on the inside of the solder. Aging performance studies revealed the thickness of both the IMC layer and the sub-layer, having a planar structure, to increase with an increase in aging time. The observed increase was essentially non-linear. Fine microscopic cracks were observed to occur at the interfaces of the planar sub-layer and the block sub-layer.

    • Author Affiliations

       

      D C Lin1 R Kovacevic1 T S Srivatsan2 G X Wang2

      1. Research Center for Advanced Manufacturing, Department of Mechanical Engineering, Southern Methodist University, 1500, International Parkway, Suite No. 100, Richardson, Texas 75081
      2. Department of Mechanical Engineering, The University of Akron, 302 E, Buchtel Avenue, Akron, Ohio 44325
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