Study on the SnAgCu solder joint between LED chip and heat sink

摘要

The solder-bonded joint is an important cooling channel of the LED device. The quality of the welding interface would determine the thermal resistance and heat capacity. The SnAgCu solder joints were studied under different reflowing processes, and the microstructure and composition of SnAgCu solder joints were investigated by SEM and associated analysis. After the SnAgCu solder join was reflowed at 240°C for 6s, a thin layer of IMCs were formed at the solder-bonded interface, and some tiny voids were formed at the solder joint. After the SnAgCu solder join was reflowed at 260°C for 6s, the interfacial IMCs would grow together and almost cover the total interface. If the reflow temperature was too high, the excessive growth of IMCs would decrease the reliability of the solder joint.