Influence of Surface Roughness on the Adhesion Hysteresis of Nano Thin Film

The influence of surface roughness on adhesion hysteresis of Cu thin films with different thickness was studied. The Cu thin films were fabricated using dc magnetron sputtering technology and their surface adhesion forces were measured using force-displacement curves of atomic force microscopy. The experiment results show that the unload curve exhibits obvious adhesion hysteresis and that the roughness and adhesion force have opposite change tendency. The theoretical analysis on the influence of thin film roughness to the adhesion hysteresis was carried out using the Johnson–Kendall–Roberts model. The results show that the load curve and unload curve constitute a closed curve and that the smoother the surface, the more obvious adhesion hysteresis, i.e. the rougher the surface, the less obvious adhesion hysteresis. The theoretical analysis results are in good agreement with the experimental results.