| 摘要 |
The present invention provides a chemical-mechanical polishing (CMP) composition for polishing a ruthenium-containing substrate in the presence of an oxidizing agent such as hydrogen peroxide without forming a toxic level of ruthenium tetroxide during the polishing process. The composition comprises a particulate abrasive (e.g., silica, alumina, and/or titania) suspended in an aqueous carrier containing a ruthenium-coordinating oxidized nitrogen ligand (N-O ligand), such as a nitroxide (e.g., 4-hydroxy-TEMPO). In the presence of the oxidizing agent, the N-O ligand prevents the deposition of ruthenium species having an oxidation state of IV or higher on the surface of the substrate, and concomitantly forms a soluble Ru(II) N-O coordination complex with oxidized ruthenium formed during CMP of the substrate. CMP methods for polishing ruthenium-containing surfaces with the CMP composition are also provided. |
