In semiconductor chip fabrication, flatness of the layer is vital, and is achieved by chemical mechanical planarization (CMP). Slurry determines mechanisms for removal, and therefore accounts for the most expense in CMP. However, conventional slurry supply systems lead to wastage of the slurry not used in polishing. Therefore, this study proposes a new slurry supply method using ionization of slurry by electrolysis. Applying an electric force to the slurry may significantly reduce slurry consumption in the CMP process. First, stainless steel was selected as a suitable electrode for the system through a simple experiment. With this system, the material removal rate was evaluated according to the applied voltage and compared to that in the conventional method under different slurry flow rates. The removal mechanism of the ionized slurry was investigated by UV-visible spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The band intensities of the intramolecular bonding structures and amounts of oxygen and Cu oxide on the surface were different depending on the electrolysis in the slurry. Accordingly, the effect of the ion-rich slurry was verified. This method is promising for efficient slurry supply systems in CMP applications as well as other manufacturing processes.
Chemical mechanical planarization (CMP) is a technology widely employed in device integration and planarization processes used in semiconductor fabrication. In CMP, the polishing pad plays a key role both mechanically and chemically. The surface of the pad, consisting of asperities and pores, undergoes repeated cycles of glazing induced by polishing followed by the recovery of roughness by a conditioning process applied during CMP. As a polymer material, the pad also experiences thermal expansion from changes in temperature. Such changes can be expressed in terms of surface roughness values, but these do not fully capture the actual changes to the pad surface. In this study, the change in pad temperature occurring during CMP was analyzed with regard to its effect on the asperity angle, and the influence on CMP outcome was assessed. The changes in the surface asperities according to the steady-state pad temperature were evaluated using various measurement methods. The change in pad roughness was characterized in terms of the asperity angle, and the contact state predicted according to temperature were validated by measuring the contact perimeter, the number of contact points, and related values. Through Scanning Electron Microscope (SEM) and micro-CT analysis, it was confirmed that in the continuous polishing process and the conditioning process, the changes in asperity angle due to changes in pad temperature affect the polishing outcome.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.