Investigation of Percarbonate Based Slurry Chemistry for Controlling Galvanic Corrosion during CMP of Ruthenium
| Autor: | Dipankar Roy, S.E. Rock, Lieve Teugels, H. P. Amanapu, M. C. Turk |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | ECS Journal of Solid State Science and Technology. 2:P205-P213 |
| ISSN: | 2162-8777 2162-8769 |
| Popis: | Chemical mechanical planarization (CMP) of Ru barrier lines is expected to become a critical processing step in the fabrication of the new interconnect-structures. However, due to its noble metal characteristics, Ru induces galvanic corrosion in its adjacent Cu lines in the wet CMP environment, and resists chemical surface modifications that are necessary to support CMP. The present work reports a slurry formulation to address these challenges of Ru-CMP, and explores the considerations for residual Cu removal using the same slurry. This alkaline (pH = 10) slurry with colloidal silica abrasives uses sodium percarbonate as an oxidizer/complexing agent in the CMP of both Ru and Cu. L-ascorbic acid is employed as a surface modifier to regulate the material removal rates of CMP, and benzotriazole is used to control galvanic corrosion of the Ru-Cu couple. With this slurry, wafer polish rates of ∼10 and ∼80 nm min −1 are measured for Ru and Cu, respectively, resulting in defect-free processed samples. Electrochemical measurements ofopencircuit potentials, potentiodynamicpolarization and impedancespectroscopy areperformedto investigatethedetailed surface reactions of Ru and Cu that facilitate material removal and control corrosion during the CMP of these metals. |
| Databáze: | OpenAIRE |
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