Atomic-Scale Study on the Dynamic and Tribological Characteristics of Nanoparticles during Post-Chemical Mechanical Polishing Cleaning

The dynamic and tribological characteristics of nanoparticles during post-chemical mechanical polishing (CMP) cleaning are significantly different from those of macroscopic-scale objects. In this work, an atomistic simulation framework was established to investigate the dynamic and tribological characteristics of the removal of silica nanoparticle from silicon substrates during post-CMP cleaning using a reactive force field (ReaxFF). The influences of the applied force distribution range, the force magnitude, and the water film on the nanoparticle dynamic characteristics were comprehensively investigated, as these critical parameters critically affect the cleaning efficiency. The results demonstrate that the increase in the force distribution range and water film thickness promote nanoparticle lifting and both jointly enhance the sliding dynamics. Simply increasing the force magnitude suppresses lifting but enhances sliding. Tribological analysis further reveals that the maximum frictional force between nanoparticles and the substrate increases with an increase in the range and magnitude of the applied force, but the influence of the water film on the frictional force shows a biphasic characteristic. The predictive reliability of the simulation framework is confirmed by nanoparticle removal experiments on 12 in. silicon wafers. This work provides atomistic insights into the nanoparticle dynamic behavior and tribological characteristics during post-CMP cleaning, offering a theoretical basis for optimizing the cleaning strategy in semiconductor processes.