Investigations on Microstructure and Mechanical Properties of the Cu/Pb-free Solder Joint Interfaces

This thesis
presents a series of mechanical test methods and comprehensively investigates
the deformation and damage behavior of Cu/Pb-free solder joints under different
loading conditions. The fracture behavior of Pb-free joint interfaces induced
by stress, deformation of solder and substrate are shown, the shear fracture
strength of the Cu6Sn5 IMC is measured experimentally for the first time, and
the dynamic damage process and microstructure evolution behavior of Pb-free
solder joints are revealed intuitively. The thesis puts forward the argument
that the local cumulative damage is the major cause of failure in solder
joints. The research results provide the experimental and theoretical basis for
improving the reliability of solder joints.