Effect of Nanoparticle Impact on Material Removal

Nanoparticle impacting on a solid surface always occurs in nano-machining processes, such as the chemical mechanical planarization (CMP) of wafers. Although the material removal induced by nanoparticle impact has been observed in some simulations and tests, the contribution of nanoparticle impact to the material removal in a real CMP process is still unclear. In the present work, a cylindrical liquid jet containing SiO2 nanoparticle impacts normally on a glass surface at speeds of 1 ms−1 and 3 ms−1. The desorption of the fluorescent nanoparticles adsorbed on the glass surface has been observed by a fluorescent microscope system and used to evaluate the contribution of the nanoparticle impact to the material removal. The experimental results indicate that the impact has a negligible effect on the material removal of the solid surface if the impacting speed is less than 3 ms−1 and the impacting time is less than 1.5 min. It may be helpful to the understanding of the material removal mechanisms in the CMP processes.