Polishing pad surface characterisation in chemical mechanical planarisation

Chemical mechanical planarisation (CMP) is a polishing process used in the fabrication of silicon wafers to achieve a globally planar wafer surface. The removal of material from the wafer is dependant upon the surface properties of the polishing pad along with other process conditions. Without regeneration of the pad surface during polishing, the rate of material removal rapidly reduces over time. By evaluating the deterioration of the pad surface during polishing, the relationship between polishing pad surface feature degradation and the effect on polish rates is analysed. Initial work assesses the characterisation of the change in the pad surface features using bearing curve parameters.