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Real Time Nanoscale Cleaning Phenomenon Observation during PVA Brush Scrubbing by Evanescent Field

Cleaning phenomenon is considered as nano-particle behaviors near the surface in nano-scale. The phenomenon concerns the removal of the nano-particle from the wafer surface to be cleaned, and the occasional reattachment of the nano-particle to surface in Post-CMP cleaning process. However, residual contamination on the wafer has been usually inspected only before and after cleaning process. Therefore, removal and reattachment mechanism of nano-particles on the surface have not already clearly known. Hence, we have been establishing dynamically visualization of cleaning phenomena on the surface applying localized light called evanescent light generated by internal reflection. In this article, we discuss the validity of our proposed optical method to observe nano-particle removal during PVA brush scrubbing in real time, by demonstrating removal of 100 nm fluorescent silica-nano-particles from a glass surface. Consequently, the mutual scrubbing behavior between nano-particles and PVA brush would be identified by fluorescent and non-fluorescent wavelength scattering light.