Yield effects of interactions between high polymer forming metal etch processes and postetch ash processes

摘要

We have demonstrated a correlation between post-metal etch ashrate performance and yield on CMOS technology integrated circuit (IC) product wafers etched at metal etch with high polymer producing recipes. This paper presents details of high polymer forming metal etch processes and two novel techniques developed for quantifying the amount of polymer formed during etch. Data are presented which illustrate a correlation between electrical test yield, post metal etch ashrates and the amount of polymer formed during the etch. Finally, recognizing that the metal etch recipe/ashrate correlation does not explain all forms of yield loss due to leakage, we suggest other areas for investigation.