Development of Innovative Fringe Locking Strategies for Vibration-Resistant White Light Vertical Scanning Interferometry (VSI)

Abstract:

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White light interferometry has become an important method for measuring micro surface profiles with a long vertical range and nano-scale resolution. However, environmental vibration encountered in in-field optical inspection is usually unavoidable and it affects measurement performance significantly. Isolating vibration sources from the measurement system sometimes is not completely effective, especially within complicated in-field fabrication environment. Therefore, in this research we aim to develop a novel method in achieving white-light fringe-locking condition during vertical scanning processes. The developed optical system consists of white light source, a Mirau objective, a PZT vertical scanner, an optical band-pass filter and two image sensing devices. The developed system generates a high and a low coherent interferograms, simultaneously captured by two charged coupled devices (CCDs). The high coherent interferogram is employed to detect high-speed nano-scale displacement and direction of the external vibration. An innovative real time fringe-locking operation is performed and a new vertical scanning technique is performed accordingly to isolate vertical scanning from environmental disturbances. The feasibility of the anti-vibration VSI system is verified by performing some of industrial in-field examples. Based on the experimental result, the fringe locking technique can improve the measurement result.

Info:

Periodical:

Edited by:

Yuri Chugui, Yongsheng Gao, Kuang-Chao Fan, Roald Taymanov and Ksenia Sapozhnikova

Pages:

89-94

DOI:

10.4028/www.scientific.net/KEM.437.89

Citation:

L. C. Chen et al., "Development of Innovative Fringe Locking Strategies for Vibration-Resistant White Light Vertical Scanning Interferometry (VSI)", Key Engineering Materials, Vol. 437, pp. 89-94, 2010

Online since:

May 2010

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$35.00

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