Study of the humidity-controlled CeO2 fixed-abrasive chemical mechanical polishing of a single crystal silicon wafer. (February 2023)

• Record Type: Journal Article
• Authors: Li, Gengzhuo; Xiao, Chen; Zhang, Shibo; Luo, Shengquan; Chen, Yuhan; Wu, Yongbo
• Is Part Of: Tribology international. Volume 178(2023)Part B
• Publication Date: 2023-02
• Subjects: Ultra-thin wafer -- Chemical mechanical polishing -- Fixed-abrasive polishing -- Tribochemical polishing; Tribology -- Periodicals; 621.89
• DOI: 10.1016/j.triboint.2022.108087
• Languages: English
• ISSNs: 0301-679X

Abstract

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. Graphical Abstract: ga1 Highlights: Water molecules are indispensable in the removal of silicon by CeO2 abrasives. Silicon and CeO2 can undergo tribochemical reactions in the presence of water. The rate of CeO2 fixed-abrasive polishing increases with ambient humidity. The optimum polishing performance is achieved under saturated humidity.