Dissolution and Removal of Ceria Particles by Post-CMP Cleaner

Chemical mechanical planarization (CMP) employing ceria (CeO2) abrasives is widely regarded as a critical process in semiconductor manufacturing due to their superior removal rates for SiO 2 films compared to other abrasives. However, the efficient removal of ceria residues from the surface remains a significant challenge. Ceria particles are strongly adhered to SiO 2 surfaces through both chemical and electrostatic interactions. In this study, we developed a post-CMP cleaning solution capable of chemically dissolving ceria residues. Fundamental investigations revealed that the combined use of fluoride, acid, and a reductant significantly enhances cerium dissolution efficiency. The fluoride-containing cleaner also demonstrated excellent performance in post-CMP cleaning of surfaces polished with ceria-based slurries. Moreover, we discovered that non-fluorinated additives exhibit cerium removal efficiencies comparable to fluoride-containing chemicals. The cleaner formulated with these additives is more compatible with various films compared to fluoride-based formulations.