Paper
29 June 2012 Improved signal to noise ratio in actinic EUVL mask blank inspection
Takeshi Yamane, Tsuneo Terasawa
Author Affiliations +
Abstract
We have developed actinic inspection systems to detect multilayer phase-defects with dark field imaging. Although a prototype system for full-field inspection is available for half-pitch (hp) 16 nm node from the viewpoint of inspection sensitivity, but the inspection time for such a full-field area of a mask requires 4.8 hours and hence the technique is not viable for a high-volume manufacturing (HVM) application. To reduce the inspection time of the prototype, its signal to noise ratio was analyzed. The result shows that an "n" times faster scanning speed would require an "n" times enhancement of the illumination intensity for the system. The intensity was enhanced by 1.7 times, by improving the optic efficiency of the system where full-field inspection time reduced from 4.8 hours to 3.25 hours, and where the detection probability was also improved. These results are applied towards the development of a HVM prototype, and for evaluating 11 nm node inspection techniques.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Takeshi Yamane and Tsuneo Terasawa "Improved signal to noise ratio in actinic EUVL mask blank inspection", Proc. SPIE 8441, Photomask and Next-Generation Lithography Mask Technology XIX, 84411H (29 June 2012); https://doi.org/10.1117/12.978628
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CITATIONS
Cited by 3 scholarly publications.
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KEYWORDS
Inspection

Prototyping

Signal to noise ratio

Photomasks

Extreme ultraviolet lithography

Imaging systems

Multilayers

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