STUDY OF APPLICATION AND RELIABILITY OF LOW MELTING POINT Sn-Zn-Bi-In-P SYSTEM LEAD-FREE ALLOYS
Author: Jusheng Ma Company: Department of Materials Science and Engineering, Tsinghua University Date Published: 2/12/2009
Pan Pacific Symposium
Abstract: The new Sn-Zn-Bi-In-P lead-free solder has good solderability, low melting point and the same reflow profile as the Sn-37Pb eutectic solder. The bonding strength of the Sn-Zn-Bi-In-P solder joint is 1.5 times higher than that of the Sn-37Pb solder joint. After thermal fatigue, the fatigue life of the former is 25% more than that of the latter. The microstructure and composition of the solder joint interface are also studied. A Zn-rich layer is found at the interface which can prevent the diffusion of Sn and Cu atoms, consequently decrease the thickness of the intermetallic compound layer. The results of EDX and TEM indicate that the intermetallic compound is Cu5Zn8. The solder paste has been produced and tested on the production line to evaluate its performance.
Key words: low temperature lead-free sold alloys, application, reliability