Plasma Etching: How CHARM-2 Can Help

CHARM-2 monitor wafers help identify wafer charging problems in both new plasma etching equipment configurations and new or modified plasma etch processes. They have been used extensively by equipment makers and IC chip makers throughout the world to help eliminate wafer charging damage in all kinds of plasma etching processes including: gate etch, contact etch, via etch, and even metal etch. Over the past 8 years, numerous technical papers have been published or presented on this subject, including the following recent paper presented at P2ID 2000. J.-P. Carrere, T. Poiroux, W. Lukaszek, C. Verove, M. Haond, G. Reimbold, and G. Turban, "Electron-Shading Characterization in a HDP Contact Etching Process Using a Patterned CHARM Wafer", 5th International Symposium on Plasma Process-Induced Damage, Santa Clara, CA, May 22-24, 2000. ABSTRACT: In this work, a CHARM-2 wafer with high aspect ratio resist patterns has been used to quantitatively characterize the electron-shading effect in a HDP oxide etch reactor. Moreover, we show by the decrease of the maximum collected current that an ion shading phenomenon also occurs for the highest aspect ratio. Finally, a careful analysis of antenna ratio effects may indicate the importance of UV assisted leakage current.