Investigation into the stress assisted damage of copper surface under single asperity: Influence of contact pressures, surfaces stress states and environments

An experiment setup was used to investigate the effects of contact loads, surface stress state and surface environment on dissolution and damage of copper surface. A range of surface stress state was generated with a four-point-bending setup on a well-polished copper sample. Single asperity contact was investigated using the cantilever tip of an Atomic Force Microscope. Controlled tip contact pressures were applied on the copper surface to mechanically stimulate the stressed surface. The experiment was performed in different environments to determine the chemical effects. Volume of material removed during the process was measured to determine material removal rate as a function of contact pressure, surface stress state and environments. It shows, as expected, higher contact pressures accelerate the material removal rates but complicated behaviors of the effects of surface stress and environments were observed. Mechanics governing material removal and their removal to Chemical Mechanical Polishing of copper was discussed.