Developing the structure of a Cu CMP model

This paper discusses how we are using Cu CMP data to develop a Cu CMP model. CMP data were taken on a non-rotating wafer using a representative dual axis rotational polisher. The data are first analyzed using a mechanical model that incorporates Preston´s law, rough surface contact mechanics, thin film fluid mechanics and basic load and moment balances. The limited success of this mechanical model, which was targeted at oxide CMP, motivated us to identify model elements that improve our understanding, including non-Prestonian behavior of the slurry and a thermally activated material removal process; i.e. chemically dominated. These model features were combined with simple mechanical model feature (load and moment balances), to successfully explain experimental observations.