ABSTRACT
Chemical–mechanical polishing (CMP) is the planarizing technique of choice to satisfy the local and global planarity constraints imposed by advanced lithography methods. The material removal mechanism of silicon dioxide CMP is similar to the removal found in glass polishing. However, CMP has its own drawback which is its dependence on layout pattern density. Layout density problem includes two stages: density analysis and fill synthesis. Pattern density can be defined as the fraction of the raised areas that affect the CMP process at a particular region on the layout. The combination of the chemical and mechanical aspects of CMP makes it a complex process to model based on physical principles. In particular, it takes into account all possible geometrical cases, which makes it applicable to modeling of the entire CMP process. The goal in copper CMP is to remove the excess copper and the unwanted barrier layer.
