Molecular dynamics simulation of mechanical properties of polystyrene nanoparticles under uniaxial compression test

Chemical mechanical planarization (CMP) is an important step in the semiconductor technology. The surface of the wafer after CMP must be defect-free with low roughness. Polymer particles are one of the potential candidates for using as abrasive in CMP. Hence, studying mechanical properties of these abrasives is of great importance. In the current study, the size-dependence elastic modulus and hardness of polystyrene (PS) nanoparticles is investigated via molecular dynamics (MD) simulations. The effect of strain on elastic modulus and hardness is examined and also the impact of strain rate on the mechanical response of PS nanoparticles during compression is studied. Additionally, the pop-in event during loading is precisely examined using volumetric analysis and shear strain distribution inside the nanoparticles is investigated. The results show that the elastic modulus increases linearly by decreasing the particle size while the hardness has a non-linear behavior. The predictions are compared with empirical measurements and good agreement is accomplished.