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Challenges and Rewards of Low-Abrasive Copper CMP: Evaluation and Integration for Single-Damascene Cu/Low-k Interconnects for the 90nm Node

  • Christopher L. Borst (a1), Stanley M. Smith (a2) and Mona Eissa (a2)

Abstract

Low-abrasive content slurries for copper (Cu) chemical-mechanical planarization (CMP) have been developed to achieve removal rate and removal uniformity comparable to conventional slurries. They can improve post-CMP defectivity, improve topography and allow operation at lower polish pressures that are more compatible with the low-dielectric constant (low-k) materials required for current and future high-performance interconnects. Integration of these slurries into a yielding product with 9-level Cu/low-k metallization requires fundamental learning and process characterization. This paper discusses the some of the challenges encountered during development, integration, and qualification of a low-abrasive Cu CMP process for Texas Instruments (TI) Incorporated's 90 nm technology node with copper/organosilicate interconnect. As abrasive content is reduced, the slurry chemistry must play a larger role in CMP removal. A more aggressive reactive chemical formulation requires an effective inhibitive component to keep Cu static etch rate low. As a result, wafer-scale process and consumable interactions, die-scale planarization efficiency, and feature-scale removal rates each become more sensitive to process changes. Pressure and temperature have larger effects on removal rate/profile than conventional slurries, and complete clearing of Cu puddled over underlying topography becomes more difficult. Successful integration of these slurries, however, can achieve excellent results in dishing and erosion topography, Cu thickness uniformity, and Cu loss in small features such as vias and landing pads. Low-abrasive content solutions are also more stable and easy to handle in slurry distribution vessels and lines, have lower scratch and residue defectivity, and have greatly extended margin for overpolish. As lowabrasive content Cu slurry options continue to evolve to become manufacturable solutions, their benefits far outweigh the costs and challenges encountered in their successful integration.

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[1] Singh, R. K., Bajaj, R. et al. , Advances in Chemical-Mechanical Planarization, MRS Bulletin, 27 (10) 746 (2002).
[2] Singh, R. K., Lee, S.-M., Choi, K.-S., Basim, G. B., Choi, W., Chen, Z., and Moudgil, B. M., Fund. of Slurry Design for CMP of Metal and Dielectric Materials, MRS Bulletin, 27 (10) 753 (2002).
[3] Steigerwald, J. M., Murarka, S. P., and Gutmann, R. J., Chemical Mechanical Planarization of Microelectronic Materials, John Wiley & Sons, New York (1997).
[4] Jindal, A., Hedge, S., and Babu, S. V., Chemical Mechanical Polishing Using Mixed Abrasive Slurries, Electrochemical and Solid-State Letters, 5 (7) G48 (2002).
[5] Guo, L. and Subramanian, R. S., Mechanical Removal in CMP of Copper Using Alumina Abrasives, Journal of the Electrochemical Society, 151 (2) G104 (2004).
[6] Borst, C. L., Gutmann, R. J., and Gill, W. N., Chemical-Mechanical Polishing of Low Dielectric Constant Polymers and Organosilicate Glasses, Kluwer, Boston (2002).
[7] Hanazono, M., Amanokura, J., and Kamigata, Y., Development and Application of an Abrasive-Free Polishing Solution for Copper, MRS Bulletin, 27 (10) 772 (2002).
[8] Matsuda, T., Takahashi, H., Tsurugaya, M., Miyazaki, K., Doy, T. K., and Kinoshita, M., Characteristics of Abrasive-Free Micelle Slurry for Cu CMP, Journal of the Electrochem Society, 150 (9) G532 (2003).
[9] Kondo, S., Sakuma, N., Homma, Y., Goto, Y., Ohashi, N., Yamaguchi, H., and Owada, N., Abrasive-Free Polishing for Cu Damascene Interconnection, Journal of the Electrochem Society, 147 (10) 3907 (2000).
[10] Kim, A. T., Seok, J., Tichy, J. A., and Cale, T. S., A Multiscale Elastohydrodynamic Contact Model for CMP, Journal of the Electrochemical Society, 150 (9) G576 (2003).
[11] Baker, A. R., The Origin of the Edge Effect in Chemical Mechanical Planarization, ECS Fall Meeting, San Antonio, TX (1996).
[12] Paul, E. and Vacassy, R., A Model of CMP: III. Inhibitors, Journal of the Electrochemical Society, 150 (12) G739 (2003).
[13] Smith, T. et al. , More Than Density: Pattern Dependencies in the Copper Era, Proceedings of the VMIC, Marina Del Ray, CA (2003).

Challenges and Rewards of Low-Abrasive Copper CMP: Evaluation and Integration for Single-Damascene Cu/Low-k Interconnects for the 90nm Node

  • Christopher L. Borst (a1), Stanley M. Smith (a2) and Mona Eissa (a2)

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