Abstract
Voids in copper thin films, observed after electroplating, have been linked to seed aging that occurs when a wafer is exposed, over time, to clean-room ambient. Oxidation of the copper seed surface prevents wetting during subsequent copper electroplating, leading to voids. Several surface treatments were employed to counteract the seed aging effect, including reduction of the copper oxide film by hydrogen, reverse plating of the copper surface, and rinsing the wafer surface with electrolyte. Each treatment was applied to wafers increasingly aged from 2 to 14 days, just prior to electroplating. Results showed a significant decrease in postelectroplating defects with all three treatments. The reduction of copper oxide by hydrogen exhibited the most marked results. An increase in surface wetting is shown by a decrease in contact angle measurements and an increase in film reflectivity for treated versus untreated copper wafers. This study shows that, although the copper surface exhibits strong aging effects over a short period of time, using proper surface treatments can eliminate such effects and voids.
Similar content being viewed by others
References
S. Ventakesan et al., Proc. IEEE-IEDM 97, 769 (1997).
D. Edelstein et al., Proc. IEEE-IEDM 97, 773 (1997).
R. Mikkola et al., Proc. IEEE-IEDM 99, 117 (1999).
J. Dini, in Modern Electroplating, ed. M. Schelsinger and M. Paunovic (New York: John Wiley & Sons, 2000), pp. 61–139.
M. Oh, D. Ramappa, D. Contestable-Gilkes, S.M. Merchant, D.E. Jones, K. Subramanian, and S.A. Lytle, Proc. Advanced Metallization Conf. 2001, ed. A.J. McKerrow et al. (Warrendale, PA: MRS Publications, 2002), pp. 85–89.
J. Lu et al., Proc. IEEE-IITC 280 (2001).
D. Contestable-Gilkes, S.M. Merchant, and M. Oh, Semiconductor FabTech, 15th ed. (London: ICG Publ. Ltd., 2002), pp. 157–162.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Contestable-Gilkes, D., Ramappa, D., Oh, M. et al. Effect of copper seed aging on electroplating-induced defects in copper interconnects. J. Electron. Mater. 31, 1047–1051 (2002). https://doi.org/10.1007/s11664-002-0041-7
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11664-002-0041-7