Characteristics of Sn-Ag-Cu Solder and Interfacial Reaction between Lead-free Metallization and Solder

摘要

Fujitsu has developed a new lead-free solder consisting of tin(Sn),silver(Ag),and copper(Cu) which has a high joint reliability with and without Pb. The new solder has a higher melting point than tin(Sn)-lead(Pb) eutectic solder. However,it also has a high joint reliability and is suitable for soldering both the currently used type of component pins and the lead-free component pins which will be widely used in the future. Thus,the new solder will promote lead-free soldering. In this paper, we studied the relation between composition of Sn-Ag-Cu solder and soldering characteristics with metallization which contains Pb. We examined on the change in mechanical properties and connection reliability with solder composition (eg., Ag and Cu contents), and also on interfacial reaction between metallization with Pb. On the basis of these examination, it becomes clear that the Sn-2.0wt%Ag-0.7wt%Cu is suitable for soldering a variety of electronic part terminals with and without Pb.