Drop performance research of silver content on the SnAgCu based lead-free solder of joint level

With the introduction of relevant laws and regulations in many countries, the electronic industry around the global has switched into lead-free age because of the harm of lead in solder on the environment and human health,. SnAgCu based solder is the most popular lead-free solder recently. The solder joint reliability has become an increasingly problem due to the change of packaging materials and packaging process. In this study, the drop reliability of lead-free solder joint, including Sn3.0Ag0.5Cu (SAC305), Sn1.0Ag0.5Cu (SAC105) and Sn0.3Ag0.7Cu (SAC0307) was studied. It can be seen that with the Ag content increasing, the thickness of the intermetallic compound layer increased. Meanwhile, the intermetallic compound particles inside the solder become smaller and the number of particles has increased. Thus with the Ag content increasing, the tensile strength of solder joint could be improved. Under dropping load, all the fracture surfaces are relatively bright and smooth. That meant that all the fracture of solder joints was brittle. With the Ag content increasing, the impact performance was: SAC0307> SAC105> SAC305.