Microstructure Study of Mix Assembly Lead-free Sn-Ag-Cu Ball Grid Array and Sn-10Cu Solder Paste

Abstract In recent years, electronic technologies have been striving to minimize the use of lead in their manufacturing and production. As a result, the electronic packaging industry is slowly transitioning from lead solder to lead-free solder. Though environmentally lead-free solders are advantageous, there are still needs some work in meeting current technological demand and requirements. In this study, the microstructure analysis on lead-free Sn-Ag-Cu Ball Grid Array (BGA) and Sn10Cu solder paste was done. The main aim of this study is to investigate the effect of isothermal aging on the microstructure of the solder paste joint and evaluate the intermetallic compound (IMC) thickness on the solder joint reliability. Optical Microscope (OM) and ImageJ software have been utilized to study the bulk solder microstructure. The results show that the bulk microstructure consists of β-Sn and Cu 6 Sn 5 / β-Sn eutectic phases. The IMC layer has undergone rapid growth with increasing aging temperature and time. The two main IMC layers (Cu 3 Sn and Cu 6 Sn 5 ) grew thicker due to high temperature. The growth kinetic of Sn10Cu resulted in 16.70 kJ/mol activation level. Therefore, the significance of the findings from this study might provide a potential answer for future development for highly reliable solder joint applications.