Abstract
This study is to investigate the joint strength of lead-free solder/Cu by the tensile test and the influence of additional elements and Ag concentration on mechanical properties. SAC305, SAC107, SAC0107 and SAC107 added 0.2mass%Bi, Sb, Ni were jointed between pure Cu plate and block by reflow process. After the tensile tests, microstructures of fracture surfaces were observed by SEM. The joint strength of SAC305 is the highest in all specimens. This result indicated joint strength of lead-free solder bulk depends on Ag concentration. The addition of Bi or Sb to SAC107 did not affected the joint strength, while the addition of Ni to SAC107 decreases the joint strength. From the observation of fracture surface, cracks occurred within the bulk solder away from either Cu or IMC.
