The micromechanical properties at bonded Au ball bonds that have undergone three different time intervals of high temperature storage (HTS) have been characterised by using nanoindentation test. 12 indentations have been made at three different locations (Au, IMC and Si area) across the bonded ball bonds to evaluate the variation of hardness with the location of indentation. It was observed that each of the elements and compound that located at the bonded ball bonds exhibit different responses and micromechanical properties upon the nanoindentation tests. Au showed the highest creep behaviour compared to that of IMC and Si. It was observed that the plastic deformation response for Au and IMC were represented in load versus depth profile through the multiple pop-in events that exhibited in loading-unloading curve of Au and IMC. Finally, it was found that the hardness value and the tendency to brittle fracture of IMC were increased with the increment of the HTS time interval.