Analysis the physical essence of microscopic fluid-based wear process in the chemical mechanical planarization process

Chemical mechanical planarization (CMP) has become the process of choice for surface global planarization for materials surfaces in the fabrication of advanced multilevel integrated circuits (ICs) in microelectronic industry. The surface planarization in the CMP is mainly realized by the tribology behavior of nanoparticles. The suspending abrasive particles impinge on the surface at some velocity and angle thus imparting energy to the surface, resulting in strain, weakened bonds, and eventually material removal. Large-scale classical molecular dynamic (MD) simulation of interaction among nanoparticles and solid surface has been carried out to investigate the physical essence of fluid-based surface planarization process. The investigation shows that the plastic deformation plays an important role in this nanoscale wear process while the contribution of dislocations to the yield stress becomes insignificant. The depth of wear is gradually decreased which makes the fluid-based wear cannot realize the global surface planarization by itself. The abrasive wear process leads to characteristic surface topography running in the same direction as the sliding motion while the adhesive wear leads to the atoms of the substrate materials adhere to the opposing surface. The adhesion wear plays an important role at lower moving speed while the abrasive wear dominates the wear process at higher moving speed which means the moving speed is one of the key factors that influence the particle wear mechanism at the nanometer scale. Different tribology behavior involved in the CMP indicates that the final surface planarization is accomplished by the synergetic effect of different wear mechanism. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3626798]