Stress evolution of Au/Cu/Au tri-layer systems during annealing

Experimental observations of the measurements of the average force per width (i.e. F/w) during deposition and annealing of Au/Cu/Au tri-layers attached to silicon substrate are reported. Systems with constant thickness of Au films (5 nm) and with different thickness of Cu films (5–20 nm) are investigated. The total force per width in a system was determined in situ by the substrate curvature measurement method with the laser scanning technique during deposition and annealing. Significant stress evolution during the first cycle of heating was observed for all samples. It was found that during the first annealing cycle, irreversible changes occur in layers. The beginning of deviation from linear part of stress curve can identify the temperature at which plastic deformation processes occurring in materials of the multilayer. Subsequent annealing cycles do not cause major changes in the stress in Au/Cu/Au tri-layer systems.