Molecular dynamics simulation of abrasive characteristics and interfaces in chemical mechanical polishing

• Published in: Applied surface science 2020-04, Vol.509, p.144676, Article 144676
• Main Authors: Nguyen, Van-Thuc, Fang, Te-Hua
• Format: Article
• Language: English
• Subjects: Diamond; Molecular dynamics; Nanotribology; Oscillating; Rolling; Sliding
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.144676

Cross-section with atomic strain and total kinetic energy of three mechanisms: (a) sliding, (b) rolling, and (c) oscillating of removing silicon substrate atoms by diamond abrasive at a moving velocity of 1 Å/ps. [Display omitted] •In sliding, the probability of atoms removed from the pathway is calculated.•Rolling achieves the highest number of atoms removed.•Oscillating removes some atoms from the substrate.•Combining sliding, rolling and oscillating mechanisms gains high-quality surface. Molecular dynamics simulation is employed to analyze the effect of sliding, rolling and oscillating movements on nanotribology properties of a diamond abrasive on a silicon substrate. The abrasive oscillating mechanism is achieved by simulating megasonic vibration-assisted on the planarization process. In this paper, the effects of abrasive size, sliding velocity, depths of polishing, rolling velocity, rolling direction, oscillating amplitude and oscillating frequency on material removal are considered. The results showed that the rolling mechanism reaches the highest number of atoms removed while the suitable oscillating mechanism gains the lowest height of asperity. The oscillating movement has remarkable results in wiping out the asperity atoms, although at a high amplitude and a low frequency causing some atoms from the flat substrate stuck to the abrasive and left some surface defects. Moreover, a multi-asperities model is set up to simulate the global-scale ability of sliding, oscillating and rolling mechanisms on polishing. This model indicates the saturated behavior of the rolling mechanism, while the lowest value of the surface roughness attained by the sliding mechanism. Combining three types of removing mechanisms could create a smooth surface with a high effective removal rate on both local and global-scales.