Wet Cleaning of Sulfur Residues Post RIE for Advanced BEOL Integration
In this study, we investigate traditional wet cleaning methods for removing sulfur residues after RIE etching. The effectiveness of sulfur removal is assessed and quantified using XPS analysis on blanket wafers and line wiggling measurements on patterned wafers. Metal lines of varying critical dimensions were etched using a sulfur-based RIE recipe. SC1 and other cleaning techniques were employed to remove sulfur residues. As illustrated in the figure below, the increase in line wiggling observed after each process step is substantially reduced by the SC1 cleaning. This effect is more pronounced for tighter pitch patterns (18p) compared to the wider (26p) ones. The full presentation will include additional wet cleaning chemicals, as well as blanket wafer data and XPS analysis, to further evaluate sulfur removal post the RIE etch.
BIOGRAPHY
Sangita Kumari is currently a Principal Process Engineer in the Surface Preparation group at Tokyo Electron Limited (TEL). She has over 20 years of industry experience. At TEL, she supports new materials and leads new process evaluations. Before joining TEL, she worked for GlobalFoundries, where she was involved in the early stages of fab startup. During her time there, she worked on several new tools and process qualifications to support multiple technology nodes. Sangita holds a PhD in Materials Science and Engineering from the University of Arizona. Her PhD research focused on single wafer Megasonic cleaning for enhanced particle removal and pattern damage control.