Reactive molecular dynamics simulation of Si chemical mechanical polishing process

Reactive molecular dynamics simulations are used to simulate the chemical mechanical polishing process of silicon surface. The simulation process is carried out to investigate the interaction between SiO₂ particle and Si surface in pure water. Both chemical and mechanical effects under different pressure between the silicon surface, water and a silica particle are clarified. This is the first application of reactive molecular dynamics simulation in the CMP area. According to the simulation results, H₂O molecules are adsorbed on both the Si substrate and SiO₂ particle surface, OH groups and H atoms are generated by the adsorption and dissociation of water. Interaction of these two surfaces leads to the formation of -Si-Si-O-Si- bond chain, and Si-Si bond of this bond chain is easier to be broken rather than the Si-O bond under the mechanical sliding effects, which leads to the removal of Si atoms. Besides, different kinds of pressure are applied to the SiO₂ particle to investigate the role of mechanical pressure effects to the CMP process, and the results show that higher pressure leads to the removal of more Si atoms. This work sheds light on the atomic chemical and mechanical details of the Si CMP process and may provide efficient ways to design the slurry composites and optimize the pressure applied in the CMP process.