Mechanical model of single abrasive during chemical mechanical polishing: Molecular dynamics simulation

The loading process among the silicon substrate, silica cluster and polyurethane pad was performed by molecular dynamics simulations. The results showed that the interaction force between the cluster and pad did not change with the working pressure at low load stage due to strong fluidity of pad atoms. But at high load stage, the interaction force would increase with increase of the working pressure owing to the reduction of pad fluidity. These demonstrate that the contact status between the abrasives and pad will change from an elastic contact to plastic contact with increase of working pressure for a chemical mechanical polishing (CMP) process. Finally, a unified mechanical model for the single abrasive during CMP under different loads was established. •The contact process among Si substrate, silica cluster and pad was studied by MD.•The force of the cluster would keep constant under low loads.•The force of the cluster increased linearly with working pressure under high loads.•Contact state between pad and abrasive changes from elastic to plastic during CMP.•A unified force model of single abrasive during CMP process was established.