To review phase and amplitude defect on extreme ultraviolet (EUV) mask with EUV intensity and phase contrast, we have developed the micro coherent EUV scatterometry microscope (micro-CSM). A coherent EUV beam was focused on a defect using a Fresnel zoneplate, where the illumination size was 140 nm diameter. Diffraction from the defect was captured by an EUV CCD camera directly. The diffraction signal was depended on the zoneplate focus, where the defect signal was efficiently detected at a best focus position. To review an actual EUV mask that has no focus-alignment pattern on surface, we developed a focusing method using a speckle signal.

Date Published: 25 October 2016
PDF: 6 pages
Proc. SPIE 9985, Photomask Technology 2016, 99851T (25 October 2016);

Published in SPIE Proceedings Vol. 9985:
Photomask Technology 2016
Bryan S. Kasprowicz; Peter D. Buck, Editor(s)