White-light interferometric microscopy for wafer defect inspection

Abstract

© 2015 SPIE.White-light imaging systems are free of laser-speckle. Thus, they offer high sensitivity for optical defect metrology, especially when used with interferometry based quantitative phase imaging. This can be a potential solution for wafer inspection beyond the 9 nm node. Recently, we built a white-light epi-illumination diffraction phase microscopy (epi-wDPM) for wafer defect inspection. The system is also equipped with an XYZ scanning stage and real-time processing. Preliminary results have demonstrated detection of 15 nm by 90 nm in a 9 nm node densely patterned wafer with bright-field imaging. Currently, we are implementing phase imaging with epi-wDPM for additional sensitivity.