Atomic surface of fused silica and polishing mechanism interpreted by molecular dynamics and density functional theory

Abstract

For fused silica, it is difficult to obtain an atomic surface with a high material removal rate (MRR), and the polishing mechanism is still a challenge. Chemical mechanical polishing (CMP) has historically used toxic and polluted ingredients. To meet these demanding constraints, it is extremely difficult to produce green CMP for fused silica. In this work, we report on the development of a novel green CMP slurry containing ceria, nicotinic acid, sodium alginate, and deionized water. After CMP, an atomic surface is achieved with a surface roughness Sa of 0.098 nm using a scanning area of 20 × 20 μm2, and the MRR is 7.65 μm/h. According to density functional theory and molecular dynamics simulations, nicotinic acid and fused silica generated a novel complex during CMP that could be peeled by active ceria by creating coordinating bonds. These findings offer an intuitive understanding of the CMP mechanism and suggest a novel method for fabricating fused silica atomic surfaces for possible usage in high-performance optical devices.