Development and Characterization of Electrodeposited Tin-Indium Alloy Microbumps for Low Temperature Assembly

The newly developed tin-indium (Sn-In) electrolyte enables the electrochemical deposition of eutectic and neareutectic Sn-In alloys containing 45-55 wt.% indium. The reflow process was successfully conducted at temperatures below 150∘C, approaching the eutectic melting point of Sn -In and remaining lower than the melting temperature of pure indium. Additionally, the results of the preliminary bonding tests are presented, demonstrating the potential of this electrolyte for lowtemperature assembly applications.