Review—Post-Chemical Mechanical Planarization Cleaning Technology

Abstract

Chemical mechanical planarization (CMP), a commonly employed process for attaining local and global planarization in integrated circuits fabrication, leaves contaminants and defects on the surface polished. Due to the miniaturization of devices, new materials/ processes for the fabrication of IC circuits are considered, introducing new post-CMP issues. As such, understanding of post-CMP cleaning process is critical to choose an appropriate method for the given material. Here, the types of contaminants and defects generated during the post-CMP process and the issues related to it are discussed. The different physical and chemical cleaning methods employed in the post-CMP cleaning process to eradicate these defects are elucidated.In particular, the PVA brushing method, which is currently preferred, is elaborated upon in detail. The various chemistries, including the newly suggested ones in recent years for cleaning different substrates, are summarized. The post-CMP cleaning methods for various materials such as Cu, Al, W, Co, Ru, InGaAs, Ge, and SiO2 are mainly addressed here. This review also provides the direction of progress for the post-CMP cleaning process in terms of evolution of new techniques and chemistries for the next generation of materials.