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Proceedings Paper

Silicon wafer temperature monitoring using all-fiber laser ultrasonics
Author(s): Jorge J. Alcoz; Charles E. Duffer
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Paper Abstract

Laser-ultrasonics is a very attractive technique for in-line process control in the semiconductor industry as it is compatible with the clean room environment and offers the capability to inspect parts at high-temperature. We describe measurements of the velocity of laser-generated Lamb waves in silicon wafers as a function of temperature using fiber- optic laser delivery and all-fiber interferometric sensing. Fundamental anti-symmetric Lamb-wave modes were generated in 5 inches < 111 > silicon wafers using a Nd:YAG laser coupled to a large-core multimode fiber. Generation was also performed using an array of sources created with a diffraction grating. For detection a compact fiber-optic sensor was used which is well suited for industrial environments as it is compact, rugged, stable, and low-cost. The wafers were heated up to 1000 degrees C and the temperature correlated with ultrasonic velocity measurements.

Paper Details

Date Published: 15 March 1998
PDF: 10 pages
Proc. SPIE 3399, Process Control and Sensors for Manufacturing, (15 March 1998); doi: 10.1117/12.302548
Show Author Affiliations
Jorge J. Alcoz, Karta Technology, Inc. (United States)
Charles E. Duffer, Karta Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 3399:
Process Control and Sensors for Manufacturing
Richard H. Bossi; David M. Pepper, Editor(s)

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