Influence of Bi on the Microstructure Evolution of Solder Joints in Microelectronics

The aim of this article is study the influence of Bi on the microstructure evolution of lead-free solder joints in microelectronics. The key factors affecting the reliability of electronic products are the interfacial reactions in solder joints, the secondary products of which are brittle intermetallic compounds. Formation and growth of intermetallic compounds are dependent from the chemical composition of solder and base material, from the effects time of the moltent solder on the base material and from the operating temperature. It is very important to mention that these reactions occur not only near the contact of the base material and molten solder in the process of melting and cooling the soldered joint, but they continue even after the solder solidifies.