Modeling of Back Pressure Distribution on the Wafer Loaded in a Multi-Zone Carrier in Chemical Mechanical Polishing

Abstract

The within-wafer non-uniformity (WIWNU) of material removal rate in chemical mechanical polishing (CMP) is important for IC manufacture. The non-uniform distributions of polishing pressure and the relative speed between the wafer and the polishing pad are main factors affecting the WIWNU. In this paper，based on the contact mechanics and the elastic plate theory, a compensate pressure computing model is presented, in which the effects of kinematic parameters are taken into acount. By modelling and calculating, the desired compensate back pressure distribution is obtained. In the last section the design of a schematic carrier with multi-zone, in which the compensate back pressure can be applied, is presented. The model and the design can be used for providing theoretical guide to the development of CMP equipments and selection of the kinematic variables in CMP process.