Molecular dynamics simulations of mechanical deformation of amorphous silicon dioxide during chemical–mechanical polishing

• Published in: Journal of applied physics 2003-09, Vol.94 (6), p.3853-3861
• Main Authors: Chagarov, Evgueni, Adams, James B.
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.1602551

We present molecular dynamics simulations of the mechanical deformation which occurs during chemical–mechanical polishing (CMP) of amorphous silicon dioxide for different geometries and relative velocities. The simulations clarify asperity shape evolution during the process of shear and reveal temperature distributions as a function of time. It was found that the ratio of radii of a particle and asperity strongly affects the amount of the material removed whereas the relative velocity has a weaker affect on it. During shear, the local temperature inside the deformed asperity is raised to 700 K at 0.5 Å/ps and up to 2200 K at 5.0 Å/ps. This temperature increase lasts for only a short time, but it can have a major impact on the amount of material removed. It was found that there could be significant deposition of the material from the particle to the slab, which can fill surface trenches and thereby make the surface smoother. An analytic model was developed for describing the amount of material removed as a function of asperity and particle radii and relative velocity. It was fit to the simulated data, and used to predict the amount of material removed at typical CMP velocities (∼1 m/s).