Study of the humidity-controlled CeO2 fixed-abrasive chemical mechanical polishing of a single crystal silicon wafer

Abstract

To address the problem of low polishing efficiency in traditional loose-abrasive chemical mechanical polishing, a humidity-controlled fixed-abrasive chemical mechanical polishing method is proposed, which uses a CeO2 pellet to perform polishing at a specific humidity level. The results of both the nano-scratch tests and the fixed-abrasive polishing experiments demonstrate that the water molecules have an irreplaceable role in the material removal of silicon and that a higher ambient humidity results in better material removal. Fixed-abrasive polishing experiments under saturated humidity can yield a surface roughness less than Ra 2 nm at an efficiency of 0.9 µm/h, and the minimum stress on the polished surface is only a few tens of megapascals. The method is validated to be effective for the stress relief process after grinding.