The Interfacial Reaction Between Sn-Ag-Cu (SAC)/Cu During Laser Soldering

Laser soldering has been widely used in electronic industries due to its excellent metallurgical bonding behaviour. In this research an investigation of intermetallic compound (IMC) formation at the interface between SAC405/Cu joint during laser soldering using different set of combined parameters was performed. As a comparison, reflow soldering was used. The characterization and microstructure analysis of samples were evaluated by using optical microscopy and a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) analysis. The properties of each solder joints were analysed. The results revealed that Parameter (II) was selected as the best results due to excellent joining properties and less formation of voids at both interface and bulk solder. The IMC formed at the interface was identified as eta-Cu6Sn5 while epsilon-Ag3Sn at the bulk solder. For the IMC thickness, the IMC layer of SAC405/Cu using Parameter (II) was thinner than IMC of SAC405/Cu after reflow soldering. Upon the revelation of these observations, using laser as a soldering method can reduce the growth of IMC layer thickness when compared to conventional reflow soldering.