Y₂O₃ nanosheets as slurry abrasives for chemical-mechanical planarization of copper

Continued reduction in feature dimension in integrated circuits demands high degree of flatness after chemical mechanical polishing. Here we report using new yttrium oxide (Y₂O₃) nanosheets as slurry abrasives for chemical-mechanical planarization (CMP) of copper. Results showed that the global planarization was improved by 30% using a slurry containing Y₂O₃ nanosheets in comparison with a standard industrial slurry. During CMP, the two-dimensional square shaped Y₂O₃ nanosheet is believed to induce the low friction, the better rheological performance, and the laminar flow leading to the decrease in the within-wafer-non-uniformity, surface roughness, as well as dishing. The application of the two-dimensional nanosheets as abrasive in CMP would increase the manufacturing yield of integrated circuits.