Correlation of actinic blank inspection and experimental phase defect printability on NXE3x00 EUV scanner

摘要

One challenge of extreme ultraviolet (EUV) mask defectivity is the severe printability of defects of the multi-layer (ML) mirror on the mask. These ML-defects are just nanometer high or deep local distortions of this ML mirror. Dedicated blank inspection tools have become available over time. One of them is the actinic blank inspection tool under development through EIDEC (Lasertec ABI). EIDEC and imec have jointly correlated its blank defect detection capability to wafers printed on ASML NXE3100 and NXE3300 scanners. Printing ML-defects were identified by wafer inspection, followed by subsequent repeater analysis, and correlated back to blank inspection. Forward correlation of ABI detections to the printed wafer was also successfully undertaken. The focus of this work has been on native defects. This paper will discuss the obtained results from the perspective of how to use ABI to assess which kind of native ML defects need to be avoided during blank fabrication.