Mechanical properties and microstructural evolution of solder alloys fabricated using laser-assisted bonding

The mass reflow (MR) process is widely used in electronic packaging interconnection. However, the conventional MR process can cause thermal damage to components and requires a long process time. The laser-assisted bonding (LAB) process is considered as an alternative soldering process for overcoming these limitations due to its extremely fast process time and high thermal selectivity. The LAB process causes low thermal damage; hence, it can be used to fabricate flexible and stretchable applications. This study investigates the mechanical properties, microstructural variation, and intermetallic reaction between the SAC 305 solder and Cu electrodes. The mechanical properties are investigated using shear tests, while the microstructure is analyzed using scanning electron microscopy and X-ray scans. Furthermore, the reliability of the LAB- and MR-produced SAC 305 solders is assessed using a high-temperature storage test. As a result, the intermetallic compound layer is found to be considerably thinner, and the volume of voids in the solder matrix is lower in the LAB-produced solder than that in the MR-produced solder. The mechanical properties of the LAB-produced solders are enhanced by these microstructural advantages.