Effect of alternating electric current on the nanoindentation of copper

Electromechanical interaction determines the structural reliability of electronic interconnects. Using the nanoindentation technique, the effect of alternating electric current on the indentation deformation of copper strips was studied for the indentation load in a range of 100 to 1600???N at room temperature. During the test, an alternating electric current of the electric current density in a range of 1.25 to 4.88?kA/cm² was passed through the copper strips. The indentation results showed that the reduced contact modulus decreased linearly with increasing the electric current density. The indentation hardness decreased with increasing the indentation deformation, demonstrating the normal indentation size effect. Using the model of strain gradient plasticity, we found that the strain gradient underneath the indentation decreased slightly with increasing the electric current density for the same indentation depth.