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Proceedings Paper

Development of a multi-electrode system for non-destructive and contactless wafer evaluation
Author(s): Justin Ndagijmana; Yuki Soh; Junpei Fukashi; K. Kobayashi; Masaaki Furuta; Hiroshi Kubota
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Paper Abstract

With the miniaturization of CMOS, the gate insulator has extremely become thin until reaching the EOT (equivalent oxide thickness) of less than 1nm in order to keep maintaining high-speed performances of devices and low electric energy consumption. Since the gate insulator is so thin, leakage current increases and the gate dielectric breakdown can easily occur. This affects the reliability of semiconductor devices. To make good devices, it is necessary to use technologies for the evaluation of the gate insulator reliability.

TDDB (Time Dependent Dielectric Breakdown) lifetime has been one of the main factors for this evaluation. In this case, a wafer is destroyed in order to be evaluated, which reduces the semiconductor yield. To solve this problem, we propose a new technique for the evaluation of the gate insulator which is a non-destructive and contactless measurement method, and thus an appropriate method for inline processes.

A voltage is applied on a Si/SiO2 specimen. A voltage source electrode and the specimen are not in contact (10micron gap). After it is charged, the specimen is irradiated by a xenon-flash-lamp. Since the energy of this pulsed light is beyond 4eV, electrons are emitted and move from Si to SiO2. It is possible to estimate the condition (the electrical conductivity) of the insulator using this phenomenon. A multi-electrode system was developed for mass production. With this system, one is able to evaluate 10 thousand points over a 12-inch wafer in 1 minute.

Paper Details

Date Published: 7 December 2013
PDF: 6 pages
Proc. SPIE 8923, Micro/Nano Materials, Devices, and Systems, 892352 (7 December 2013); doi: 10.1117/12.2033812
Show Author Affiliations
Justin Ndagijmana, Kumamoto Univ. (Japan)
Yuki Soh, Kumamoto Univ. (Japan)
Junpei Fukashi, Kumamoto Univ. (Japan)
K. Kobayashi, Kumamoto Univ. (Japan)
Masaaki Furuta, Kumamoto Univ. (Japan)
Hiroshi Kubota, Kumamoto Univ. (Japan)

Published in SPIE Proceedings Vol. 8923:
Micro/Nano Materials, Devices, and Systems
James Friend; H. Hoe Tan, Editor(s)

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