@article{Chen2026, 
author = {Lei Chen and Shehui Dang and Jinhuan Zhong and Chen Xiao and Yang Wang and Lifei Zhang and Yilong Jiang and Linmao Qian},
title = {Atomic insights into material removal mechanism in chemical mechanical polishing of silicon using a developed abrasive-free slurry},
year = {2026},
journal = {Friction},
volume = {14},
number = {9},
pages = {9441219},
keywords = {chemical mechanical polishing (CMP), interfacial mechanochemistry, abrasive-free removal, atomic surface, alkylamine, silicon},
url = {https://www.sciopen.com/article/10.26599/FRICT.2026.9441219},
doi = {10.26599/FRICT.2026.9441219},
abstract = {The atomic surface of silicon (Si) wafers without particulate contamination achieved by chemical mechanical polishing (CMP) is highly desired for advanced chip manufacturing. Traditional CMP processes usually employ abrasive-containing slurries, resulting in significant particulate residues and high-cost post-treatments. To address this challenge, a novel abrasive-free CMP slurry including only a designated chain-length alkylamine was developed based on the observed dependence between the Si surface roughness and alkylamine chain length. After polishing with the long-chain hexylamine slurry, an atomic surface without particulate contamination is achieved with a surface roughness as low as 0.13 nm, which is 85% lower than that obtained using the short-chain methylamine slurry, while maintaining a material removal rate of 57.7 nm/min. Furthermore, we established an atomic mechanistic framework that integrates interfacial chemistry with mechanical action to understand how alkylamine chain length modulates mechanochemistry in abrasive-free Si CMP. Density functional theory calculations show that long-chain alkylamines adsorb more readily but have a milder weakening effect on Si–Si bonds, whereas short-chain counterparts, despite weaker adsorption, more effectively weaken these bonds. Nanowear tests and X-ray photoelectron spectroscopy corroborate that the dynamic equilibrium between the adsorption strength and bond weakening promotes the formation of a mechanically vulnerable reaction layer composed of Ox–Si–Ny compounds, which is amenable to abrasive-free removal for atomic smoothness. Our findings shift the mechanistic paradigm from conventional abrasive-containing interfacial interactions to abrasive-free, chemically driven, adsorption-controlled removal processes. These insights offer theoretical guidelines for both academic research and industrial practice in ultra-precision manufacturing and advanced semiconductor processing.}
}