Study using ReaxFF-MD on the CMP process of fused glass in pure H_2O/aqueous H_2O_2

摘要

Based on ReaxFF-MD simulation, our work is carried out to study the chemical mechanical polishing (CMP) process of fused glass. We explored the oxidation reaction between fused glass surface and aqueous H2O2 on the atomic scale, and analyzed the micro-influence mechanism of aqueous H2O2 concentration in polishing slurry. The simulation results show aqueous H2O2 can promote the oxidation degree of fused glass surface and has a double-sided effect on atom removal. On the one hand, surface oxidation makes it difficult to form interfacial Si-(substrate)-O-Si-(abrasive) bridge bonds between substrate and abrasive, less interfacial bridge bonds cause atoms difficulty in falling off from substrate; on the other hand, surface oxidation weakens the bonding strength of Si-O bonds, then substrate surface structure becomes more unstable, promoting atom removal. In our simulation, the removal form of polishing in 5% aqueous H2O2 is dominated by single-particle atom removal, that causes better surface quality and is a more expected removal form in ultra-precision machining; but at other concentrations, cluster removal or chain removal is more likely to occur. This work provides a more microscopic understanding of the influence of aqueous H2O2 or other oxidants on the surface removal behavior of silicon-based materials.