Actinic defect inspection and characterization for extreme ultraviolet mask blanks

Extreme ultraviolet (EUV) lithography is crucial for advanced semiconductor manufacturing, relying on sophisticated mask technology to transfer intricate patterns onto silicon wafers. The integrity of the EUV mask blanks is essential for producing high-quality masks and semiconductor devices. However, defects in mask blanks, particularly multilayer phase defects, can significantly degrade lithographic quality, affecting device yield and performance. Actinic blank inspection (ABI) has emerged as the most effective strategy for evaluating the initial quality of EUV mask blanks and identifying defects that may compromise the wafer integrity. Additionally, defect characterization helps determine the nature of the defect, its printability, and its potential for repair. This review surveys recent advancements in ABI and defect characterization, covering a range of methodologies, commercial inspection tools and related research efforts that aimed at improving the detection and characterization of multilayer defects.