Chemical Mechanical Polishing (CMP) is a critical process in many industries where achieving superior surface quality through controlled material removal rates by using nano-abrasives is essential. This review examines key parameters of abrasives at the nanoscale, such as size, shape, aspect ratio, hardness, and surface modifications, through inorganic doping or organic molecule grafting and their influence on CMP performance. By analyzing recent studies, we explore how these parameters affect the tribological and chemical interactions during CMP and link these effects to the fundamental polishing mechanisms. Highlighting emerging trends, this work offers a roadmap for designing next-generation nano-abrasives that boost removal efficiency, enhance surface finish, and ensure process stability. Ultimately, controlling abrasive properties at the nanoscale is vital for advancing CMP technology toward more efficient, consistent, and high-quality results.

This study investigates hyperpolishing of Zerodur^® substrates via chemical-mechanical polishing (CMP) using silica (SiO₂) and ceria (CeO₂) nanoparticles as controlled nano-abrasives. A pre-polishing stress-mirror stage was combined with systematic use of nanoparticles of variable size to evaluate surface-state evolution via optical rugosimeter, HRSEM, cross-sectional HRTEM, and XPS. A set of hexagonal mirrors with a circumscribed diameter of 30 mm was polished for one hour with each nanoparticle type. All tested slurries significantly improved surface quality, with both the smallest (37 nm) and largest (209 nm) SiO₂ particles achieving similar final roughness, though larger particles showed a slight performance advantage that could be offset by longer polishing with smaller particles. CeO₂ nanoparticles (30 nm) produced even better process efficiency and surface finishes than 37 nm SiO₂, demonstrating higher chemical-mechanical polishing efficiency with CeO₂. Sequential polishing strategies, first with 209 nm SiO₂, then with 37 nm SiO₂ and 30 nm CeO₂, also enhanced surface quality, confirming trends from single-particle trials. One of the most effective protocols was adapted and scaled up to 135 mm Zerodur^® mirrors with spherical and plano geometries, representative of precision optical components. The strategic approach adopted to achieve a high-quality surface finish in a reduced processing time relies on the sequential use of nanoparticles acting as complementary nano-abrasives. Indeed, applying two hours of polishing with 209 nm SiO₂ followed by two hours with 37 nm SiO₂ yielded exceptional results, with area roughness (Sa) values of 1 Å for spherical and 0.9 Å for plano surfaces. These results demonstrate the capability of nanoparticle-assisted CMP to produce sub-nanometric surface finishes and offer a robust, scalable approach for high-end optical manufacturing.