Micromechanical characterisation of Sn-Ag-Cu solder FCOB interconnects at ambient and elevated temperatures

This paper characterises the micromechanical properties of lead free solder joints formed from fine pitch flip chip interconnection. Nanoindentation, which is suitable for the ultra-fine and complex microstructure in small volume materials, was used to test the micromechanical properties of solder joints, including hardness, elastic modulus and creep properties, at both ambient and elevated temperatures. A hot-stage, which allows test specimens heated up to 500°C, is used for the in-situ micromechanical study at elevated temperatures. Finally, the micromechanical properties obtained from nanoindentation were correlated with the microstructure and intermetallics identified by SEM.