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Journal of Micro/Nanolithography, MEMS, and MOEMS • Open Access

Impact of the phase defect structure on an actinic dark-field blank inspection signal and wafer printability

Paper Abstract

In extreme ultraviolet lithography, reducing the number of phase defects (PDs) on mask blanks is a critical issue because the PDs cause degradation of the printed pattern quality. To minimize the number of printable PDs, covering PDs beneath an absorber pattern is an effective way of addressing the problem. Therefore it becomes necessary to detect the PDs and pinpoint their locations by a blank inspector. In this work, a three-dimensional analysis of PDs has revealed that some PDs can grow and propagate in an angular direction away from the normal to the substrate surface. The impact of the inclination angle on the printing performance was evaluated by calculating printed pattern images using a simulator. A PD with an inclination angle of 1 deg corresponds to a 1-nanometer positional shift compared with a position defined as surface topography of a defect as observed by an atomic force microscope or by some nonactinic defect inspector. However, an actinic blank inspection (ABI) tool with high-magnification optics can pinpoint the actual location of the PDs. Covering a PD under an absorber pattern, by a shifting of the pattern based on the information of the PD’s location obtained by the ABI tool, works quite well.

Paper Details

Date Published: 1 March 2013
PDF: 6 pages
J. Micro/Nanolith. MEMS MOEMS 12(2) 021002 doi: 10.1117/1.JMM.12.2.021002
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 12, Issue 2
Show Author Affiliations
Tsuyoshi Amano, EUVL Infrastructure Development Ctr., Inc. (Japan)
Yukiyasu Arisawa, EUVL Infrastructure Development Ctr., Inc. (Japan)
Tsuneo Terasawa, EUVL Infrastructure Development Ctr., Inc. (Japan)

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