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Proceedings Paper

Evaluation of near-surface microdefects in Czochralski-Si wafers after a CMOS process by an infrared interference method
Author(s): Yutaka Kitagawara; Ken-ichi Aihara; Satoshi Oka; Takao Takenaka
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Paper Abstract

Properties of near-sruface microdefects (NSMDs) 0-10 micrometers deep of Czochralski-Si wafers have been analyzed to understand how the as-grown crystal qualities are related to the NSMD characteristics after a CMOS thermal simulation. The microdefects are observed by an infrared interference method after a preliminary study to find the optimum condition for the high-sensitivity measurements. The results are compared with those by the infrared laser scattering tomography. Size distribution of the observed microdefects are analyzed to classify them into 'large-size' group and 'small-size' group. Comparing the NSMD characteristics after the CMOS process with those for the as-grown wafers, density of the relatively 'small- size' NSMDs is found to increase by the amount 105-106cm-3 during the CMOS proces. The increase is especially notable for the wafers with low as-grown microdefect densities. In addition, these NSMD characteristics are shown to be related to the qualities of the MOS gate oxide films formed on the CMOS processed wafers. The time-zero dielectric breakdown characteristics are correlated with the NSMD density. On the other hand, the time-dependent dielectric breakdown characteristics are related to the amount of 'small- size' NSMDs generated during the CMOS process.

Paper Details

Date Published: 18 September 1995
PDF: 9 pages
Proc. SPIE 2638, Optical Characterization Techniques for High-Performance Microelectronic Device Manufacturing II, (18 September 1995); doi: 10.1117/12.221204
Show Author Affiliations
Yutaka Kitagawara, Shin-Etsu Handotai Co., Ltd. (Japan)
Ken-ichi Aihara, Nagoya Univ. of Commerce & Business Admin. (Japan)
Satoshi Oka, Shin-Etsu Handotai Co., Ltd. (Japan)
Takao Takenaka, Shin-Etsu Handotai Co., Ltd. (Japan)

Published in SPIE Proceedings Vol. 2638:
Optical Characterization Techniques for High-Performance Microelectronic Device Manufacturing II
John K. Lowell; Ray T. Chen; Jagdish P. Mathur, Editor(s)

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