Ultra clean processing of silicon surfaces 2000 vol:76-77 pages:39-42
One of the main tasks of the post Chemical Mechanical Planarization (CMP) cleaning step is to remove slurry residues left on the surface after the polishing process. It has been found that very selective deposition of the slurry particles on the different substrate materials is possible. Removal of these slurry residues was evaluated using a single wafer megasonic cleaning system with respect to post Cu CMP cleaning. This setup was also equipped with a novel drying technique based on surface tension gradient drying. It has been found that the use of megasonic cleaning with DI water is already very efficient in removing CMP slurry residues from the surface. Further improvement of the process is possible by combining megasonic cleaning with an appropriate chemistry. Roughness data indicate a decrease of a factor of more than 2 by selecting the appropriate chemistry and dilution.