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Proceedings Paper

Polarization control for enhanced defect detection on advanced memory devices
Author(s): Byoung-Ho Lee; Dong-Chul Ihm; Jeong-Ho Yeo; Yael Gluk; Doron Meshulach
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Paper Abstract

Dense repetitive wafer structures, such as memory cells, with a pitch below the wavelength of the illumination light may take on effective birefringent properties, especially in layers of high refractive index materials such as silicon or conductors. Such induced "form birefringence" effects may result in dependency of the optical response on the illumination polarization and direction. In such structures, control over the polarization of the light becomes important to enhance signal-to-noise ratio (SNR) of pattern defects. We present defect detection results and analysis using DUV laser illumination for different polarization configurations and collection perspectives on Flash RAM devices. Improvement in detection SNR of bridge defect type is observed with linear illumination polarization perpendicular to the pattern lines. Generally, for small design rules (smaller than wavelength) polarization effects become more evident. Also, for smaller defect sizes, detection strongly depends on control of the illumination polarization. Linear polarization perpendicular to the pattern showed penetration into the structure even though the pitch is smaller than the illumination wavelength.

Paper Details

Date Published: 24 March 2006
PDF: 6 pages
Proc. SPIE 6152, Metrology, Inspection, and Process Control for Microlithography XX, 61521Q (24 March 2006); doi: 10.1117/12.656004
Show Author Affiliations
Byoung-Ho Lee, Samsung Electronics Co. Ltd. (South Korea)
Dong-Chul Ihm, Samsung Electronics Co. Ltd. (South Korea)
Jeong-Ho Yeo, Applied Materials (Israel)
Yael Gluk, Applied Materials (Israel)
Doron Meshulach, Applied Materials (Israel)

Published in SPIE Proceedings Vol. 6152:
Metrology, Inspection, and Process Control for Microlithography XX
Chas N. Archie, Editor(s)

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