Interfacial Morphology Studies of Sn-3.8Ag-0.7Cu Alloy on Different Substrates

<jats:p>Since the ban of lead containing solders, eutectic SAC solders has been claimed to posses better properties compared to other series of lead free solders. As the technology trend for portable devices change over time, solder joints are continuously miniaturized. The VLSI in modern devices will subject the solder joints to repeated temperature cycling during both assembling and use due to higher I/O. These lead free solders are prone to excessive intermetallic compound (IMC) growth at the interface between the solder and the substrate due to the reasons cited earlier. The most common substrate used in electronic packaging is Cu while Au or its alloys are often used as metallization layer. In this study PCBs coated with both Cu and Au to study the interfacial morphology of Sn-3.8Ag-0.7Cu (SAC387) alloy with these metals. SEM imaging and EDX analysis were used to observe the interfacial layers and to confirm formation of IMCs. IMCs formed between Au-solder are more blocky-like compared to those formed between Cu-solder. Thus further studies must be conducted to resolve this issue as Au is a commonly used metallization materials.</jats:p>