A static model for scratches generated during aluminum chemical-mechanicalpolishing process: Orbital technology

In this work, we explored the analogy between the scratches formed on a pol ished surface and the indentation used in the material hardness testing. A static hardness model proposed on the basis or this analogy is able to expl ain quite successfully the experimental results such as the depth of the sc ratches and the vulnerability of the aluminum film, under the assumption th at the particle penetration is facilitated by a stress concentration. It is suggested that the stress redistribution needed might be caused by the inc ompleteness of pad-wafer contact due to the pad surface roughness. We also found that a scratch in its plane-view is shaped by the kinetic equation go verning the pad-wafer relative movement which is deemed as a further eviden ce for our hypothesis that a scratch is generated by a protrusion on the pa d holding a particle against the wafer and forcing it into the film with th e aid of the stress concentration.