A Molecular Dynamics Study on Cutting-Strategy-Dependent Subsurface Damage in Single-Crystal Silicon During...

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Physics

Background:

• Ultra-precision machining of single-crystal silicon is crucial for semiconductor manufacturing.
• Understanding material removal and subsurface damage (SSD) mechanisms is vital for process optimization.

Purpose of the Study:

• To investigate the material removal mechanism and subsurface damage (SSD) evolution in single-crystal silicon during ultra-precision machining.
• To evaluate the impact of different cutting strategies on cutting response, stress, morphology, and defect evolution using molecular dynamics (MD) simulations.

Main Methods:

• Developed a three-dimensional molecular dynamics (MD) model for single-crystal silicon.
• Employed Tersoff and Morse interaction potentials to simulate machining processes.
• Analyzed cutting forces, stress distribution, surface morphology, and defect evolution under various cutting strategies.

Main Results:

• The multi-pass cutting strategy effectively reduced mean cutting forces and suppressed high-stress concentration regions (>7 GPa).
• Subsurface damage (SSD) formation was dominated by lattice distortion and amorphous phase transformation, linked to localized high von Mises stress.
• A multi-pass strategy with a single-pass cutting depth below 1 nm achieved a favorable balance between machining efficiency and surface integrity.

Conclusions:

• Multi-pass cutting offers a viable strategy for minimizing subsurface damage and optimizing ultra-precision machining of silicon.
• Atomistic insights from MD simulations are crucial for understanding and controlling damage mechanisms in brittle materials.
• Findings provide guidance for process optimization in the ultra-precision machining of semiconductor materials.