Chemical-mechanical planarization (CMP) is inherently a dirty process. Defect minimization in CMP is of great interest to the overall success of the manufacturing of sub-0.20 μm devices. In this article, some general aspects of contamination in CMP and the effect of CMP defects on the manufacturing of devices will be reviewed. Defects that are created during a CMP process can be classified into four categories: particulate, metallic, organic, and others. Additives to CMP slurries that can modulate interfacial chemistry and electrochemistry of a solid film/solution system will be reviewed. CMP defects and their minimization are also associated to CMP process itself. General approaches that can be used for removing contaminants after CMP will be analyzed. Because defects are mostly formed as a result of the interaction between the slurry and the film being polished during CMP, the reduction of defects can be achieved through a fundamental understanding of the surface chemistry and electrochemistry aspects of the CMP system.