2 April 2010 Calibration of 25-nm pitch grating reference by high-resolution grazing incidence x-ray diffraction
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Proceedings Volume 7638, Metrology, Inspection, and Process Control for Microlithography XXIV; 763810 (2010); doi: 10.1117/12.846519
Event: SPIE Advanced Lithography, 2010, San Jose, California, United States
Abstract
We have developed high-resolution grazing incidence x-ray diffraction (HRGIXD) pitch calibration system with wavelength of 0.1540593 nm (Cu K α1 line). In order to ensure accuracy of this calibration system, we measured average pitch of a 100-nm pitch grating reference, which is being used for magnification calibration of a current critical-dimension scanning electron microscope (CD-SEM), and compared with the results of deep ultra violet (DUV) laser diffraction pitch calibration system with wavelength of 193 nm. The average pitch determined by the HRGIXD system agrees with that determined by the DUV laser diffraction system within the range of uncertainty. We measured average pitch of a fine 25-nm pitch grating, which will be used for magnification reference. In the DUV laser diffraction, wavelength of 193 nm no longer satisfies diffraction condition for the 25-nm pitch grating, because wavelength must be shorter than twice of the pitch size. On the other hand, wavelength of x-ray is much shorter than the pitch size. We have successfully detected more than ten sharp diffraction peaks corresponding to the 25-nm period. The average pitch of the grating is measured in very high-accuracy with standard uncertainty of less than 10 pm.
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Yoshiyasu Ito, Kazuhiko Omote, Yuko Okazaki, Yoshinori Nakayama, Hiroki Kawada, "Calibration of 25-nm pitch grating reference by high-resolution grazing incidence x-ray diffraction", Proc. SPIE 7638, Metrology, Inspection, and Process Control for Microlithography XXIV, 763810 (2 April 2010); doi: 10.1117/12.846519; https://doi.org/10.1117/12.846519
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KEYWORDS
Diffraction gratings

Diffraction

Calibration

X-rays

Deep ultraviolet

X-ray diffraction

Grazing incidence

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