Study on formation mechanism and suppression of subsurface damage during nano-grinding of monocrystalline silicon

The subsurface damage generated during nano-grinding of silicon wafers limits its service life. It is urgent to study the formation mechanism and suppression methods of subsurface damage during nano-grinding of monocrystalline silicon. In this study, a molecular dynamics simulation model of nano-grinding monocrystalline silicon was established to study the formation mechanism of subsurface damage. Then, the influence mechanism of grinding parameters on grinding force, grinding temperature and subsurface damage formation during grinding was studied. Finally, the damage suppression strategy of nano-grinding monocrystalline silicon was proposed. The results showed that the main subsurface damage formation mechanism was structural phase transformation and amorphousness during nano-grinding monocrystalline silicon. The original Si-I phase formed Si-II phase, Si-III phase, Si-IV phase, bct5-Si phase and amorphous phase under extrusion and shear. The increase of grinding depth led to the increase of grinding force and grinding temperature, while the increase of grinding speed led to the decrease of grinding force and the increase of grinding temperature. The increased grinding force was the main reason for the serious subsurface damage, and a certain degree of high temperature was beneficial to inhibit the subsurface damage of monocrystalline silicon. In nano-grinding of monocrystalline silicon, subsurface damage can be suppressed by reducing grinding depth and increasing grinding speed.