Wetting behavior and interfacial characteristic of eutectic In-Ag solders on Au thin films

Abstract

Soldering electrical contacts to gold thin films is a matter of consideration due to high soldering temperature, restricted wetting, excessive scavenging and low strength offered by most of the common soldering alloys. Indium alloys offer certain benefits for gold soldering justifying their increased cost. In the present study, hypo-, hyper- and eutectic In-Ag solder were prepared and investigated for compositional and structural homogeneity, soldering temperature, contact angle, spreading factor, scavenging zone and scavenging phase (i.e. AuIn2). It was found that addition of silver (~3.5%) ameliorated the above mentioned characteristics for better control of soldering practice with gold thin films besides lowering the soldering temperature.