Leveraging blanket wafer film inspection to efficiently characterize root cause for lithographic micro-masking patterning defects

This paper presents a methodology that uses unpatterned wafer inspection to detect material-related micro-masking defects in a tri-layer stack. We investigated two approaches to detect the source of the micro-masking defect, namely (i) defect source analysis (DSA) comparing patterned-wafer inspection results at post-develop and post-stack-etch, and (ii) unpatterned-wafer inspection of individual blanket film monitors. Blanket-film monitoring was able to successfully demonstrate the source of the defect and has reduced the Mean Time to Detect (MTTD) dramatically. This paper also discusses the advantage of unpatterned wafer inspection for baselining and controlling blanket film defectivity and validates an integrated wafer defectivity improvement strategy.