Mask 3D effect reduction and defect printability of etched multilayer EUV mask

摘要

We report on the reduction of the mask 3D effect in an etched 40-pair multilayer extreme ultraviolet (EUV) lithographymask by measuring the printed ΔCD (horizontal–vertical) on exposure with a high-NA small field exposure tool(HSFET). We compared these patterns with those of a conventional Ta-based absorber EUV lithography mask. Next, weexamined the programmed pattern defect printability of the etched 40-pair multilayer EUV lithography mask and showedthat defect printability of the etched multilayer mask was hardly influenced by the direction of EUV illumination. Weconclude that the mask 3D effect reduction contributes to simple specifications of the mask pattern defect printability inEUV lithography.