Engineering functionalized PS/mSiO2 composite particles with controlled meso-shell thickness for chemical mechanical planarization applications

The functionalized PS/mSiO(2) composite particles (CPs), featuring polystyrene cores and mesoporous silica shells, were introduced into chemical mechanical planarization (CMP) processes. The PS/mSiO(2) CPs presented a higher material removal rate (MRR) and a lower root-mean-square (RMS) roughness than conventional solid silica particles. The MRR (48-75 nm/min) and RMS roughness (0.16-0.26 nm) of the finished oxidized silicon wafers decreased as the shell thickness (30-50 nm) reduced. The reduced RMS roughness was attributed to their relatively low hardness and modulus. The enhanced MRR resulted from their strong adsorptivity for the active components in slurries. The non-damage surfaces were efficiently achieved from the synergetic effect of the non-rigid mechanical properties and the enhanced chemical reactivity in the interfaces between PS/mSiO(2) CPs and substrates.