Nano-sized, nonreacting, noncoarsening Al2O3 particles have been incorporated into eutectic Sn-Zn solder alloys to investigate the microstructure, hardness and shear strength on Au/Ni metallized Cu pads ball grid array substrate (BGA). In the plain Sn-Zn solder joint and solder joints containing Al2O3 nano-particles, a scallop-shaped AuZn3 intermetallic compound layer was found at the interfaces. In the solder joints containing Al2O3 nano-particles, a fine acicular-shaped Zn-rich phase and Al2O 3 nano-particles were found to be homogeneously distributed in the β-Sn matrix. The shear strengths and hardness of solder joints containing higher percentage of Al2O3 nano-particles exhibited consistently higher value than those of plain solder joint and solder joints containing lower percentage of Al2O3 nano-particles due to control the fine microstructure as well as homogeneous distribution of Al 2O3 nano-particles acting as a second phase dispersion strengthening mechanism. The fracture surfaces of plain Sn-Zn solder joints exhibited a brittle fracture mode with smooth surfaces while Sn-Zn solder joints containing Al2O3 nano-particles showed a typical ductile failure with very rough dimpled surfaces.
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Safety, Risk, Reliability and Quality