Effects of Grinding Penetration Depth and Abrasive Grain Spacing on Atomic Interactions and Material Removal Mechanisms in Silicon during Ultrasonic Vibration-Assisted Grinding: A Molecular Dynamics Study

Abstract

Grinding is an important finishing process for hard, brittle materials like silicon, where atomic-level finishing is critical for semiconductor and microelectronic applications. Ultrasonic vibration-assisted grinding has been shown to enhance grinding efficiency beyond conventional methods, but several of its atomic-level mechanisms remain incompletely understood. The interaction among the following was investigated in this study: mean abrasive grain spacing, grinding penetration depth, and abrasive grain physical properties. Atomic interactions and behaviors of the grinding process were modeled using molecular dynamics. An equilibration of 10 ns was first set up, during which extrinsic variables were manipulated to produce an equivalent environment, allowing the sample to evolve independently. This equilibration step was essential to achieve stabilization, since the potential and kinetic energies were −4.69 eV and 0.02 eV, respectively. It was observed that changing the grinding penetration depth from 10 Å to 16 Å significantly affected important atomic parameters: the number of detached atoms increased from 2231 to 2495, whereas the maximum stress rose from 10.26 to 12.27 GPa. This result was remarkable because it indicated strong stress localization and enhanced atomic bond breakage at deeper penetration depths, revealing the onset of severe atomic deformation. The highest force of the system increased from 606.67 to 725.05 GPa·nm². Increasing the mean abrasive grain spacing between abrasive grains from 31 to 45 Å resulted in a lower number of dissociative atoms (2231 → 2154) and a shallower penetration depth (10.75 → 10.29 Å). The maximum stress and, in turn, the force were found to decrease uniformly from 10.26 to 9.89 GPa and from 584.80 GPa·nm² to 560.80 GPa·nm², respectively.