Investigation of a facile plasma-driven method for in situ cleaning of metal-based contamination

Abstract

Self-cleaning of tin contaminants was realized utilizing self-driven hydrogen plasma. Cleaning rates of 0.7-6 nm min-1 were achieved to remove discontinuous tin particles at different powers. The analysis of topography and cross-sectional morphology revealed that the removal of tin particles was achieved through top-down cleaning with hydrogen plasma, where the upper part of spherical tin particles was always more intensely cleaned under the synergistic effect of hydrogen atoms and ions due to the vertical incidence of ions to substrate during the whole cleaning process. The redeposition of tin atoms caused by physical sputtering and its promotion of the chemical cleaning effect was observed for the first time. Reflectance recovery measurements during cleaning and surface analysis of the substrate after cleaning indicated that nondestructive cleaning with reflectance loss of less than 1% can be achieved at a relatively low power of 120 W. The plasma-induced substrate damage, such as holes and valleys, reduced the reflectance of the substrate when cleaning was performed at a high power ＞120 W, which should only be considered to apply in the condition without substrate exposed. This study provides a comprehensive understanding of the removal of discontinuous tin particles using the in-situ self-driven plasma cleaning method, which also provides meaningful guidance for the extension of this method in other potential application fields.

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

“…By combining these two factors, tin contamination was introduced using the high-temperature vapor deposition method, physical vapor deposition (PVD). In accordance with the literature [12], the contamination was deposited on the MLM in a non-uniform particulate morphology. To the greatest extent possible, the evaporative coating was acquired during our sample preparation to mimic the real morphology of contamination.…”