A single-shot line-scanning spatially dispersed short coherence interferometer using Fourier transform profilometry

M. Hassan, H. Martin, X. Jiang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Single-shot inspection at nanoscale resolution is a problematic challenge for providing on-line inspection of manufacturing techniques such as roll-to-roll processes where the measurand is constantly moving. An example of such a measurement challenge is defect detection on vapor barrier films formed by depositing an aluminum oxide layer several tens of nanometres thick on a flexible polymer substrate. Effective detection and characterisation of defects in this layer requires a single-shot approach with nanometre scale vertical resolution. This paper describes a line-scanning interferometer where a short coherence light source having a 25 nm linewidth source is spatially dispersed across the measurand thus encoding spatial position along a profile by wavelength. Phase shift interferometry (PSI) can be used to decode phase and thus height information, but requires multiple image captures. In order to realise single-shot measurement which is more suitable for online applications, a Fourier transform profilometry (FTP) approach is necessary. This paper explores the implementation of the FTP approach and presents a comparison of the measurement capability of FTP with the previously reported PSI method.

Original languageEnglish
Title of host publicationLaser Metrology and Machine Performance XI - 11th International Conference and Exhibition on Laser Metrology, Machine Tool, CMM and Robotic Performance, LAMDAMAP 2015
Publishereuspen
Pages2-7
Number of pages6
ISBN (Electronic)9780956679055
Publication statusPublished - 2015
Event11th International Conference and Exhibition on Laser Metrology, Coordinate Measuring Machine and Machine Tool Performance - Huddersfield, United Kingdom
Duration: 17 Mar 201518 Mar 2015
Conference number: 11

Conference

Conference11th International Conference and Exhibition on Laser Metrology, Coordinate Measuring Machine and Machine Tool Performance
Abbreviated titleLAMDAMAP 2015
CountryUnited Kingdom
CityHuddersfield
Period17/03/1518/03/15

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