Development of mesoporous abrasives and its unprecedented polishing performance elucidated by a novel atomic model

Abstract

It is a challenge for solid abrasives to control atomic damages. To reduce damage, solid core and mesoporous shell sSiO2@mSiO2 abrasives were prepared, and novel green chemical mechanical polishing (CMP) was developed. The CMP slurry consists of ethylene glycol, guanidine carbonate, hydrogen peroxide and prepared mesoporous abrasives. A novel atomic model of mesoporous structure is proposed based on molecular dynamics (MD) simulations. Prior to CMP, samples were roughly polished by ceria slurry. After CMP, surface roughness, material removal rate and thickness of damaged layer were improved by 25 %, 47 % and 47 %, respectively. Formation mechanism of densification damage was suggested. High shear stress is a necessary condition for atomic densification, i.e., damages, and friction and adhesion between abrasives and workpiece promoted the formation of densification. Moreover, mesoporous structure with size increasing from 0 to 5 nm lessened the densification atoms from 13364 to 4551. X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and Raman spectroscopy reveal that silanol was generated in guanidine carbonate solution. The silanol was dehydrated and condensed, producing Si–O–Si bridge bonds and falling off with surface atoms. The proposed mesoporous model and developed CMP offer new insights to roundly improve the polishing performance.