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Title: Thin Film Optical Metrology Using Principles of Wavefront Sensing and Interference
Author: Faichnie, David Malcolm
ISNI:       0000 0001 3456 2608
Awarding Body: Heriot-Watt University
Current Institution: Heriot-Watt University
Date of Award: 2007
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The work contained within this thesis considers the applicability of wavefront sensing to the problem of laminate and thin film metrology and considers whether such technology can be applied to the problem of in-situ thickness measurement. Some initial investigations were carried out to develop new applications based on current technology. The main body of the work investigated the development of a thickness monitor based on measuring the separation of surface reflections and the further development required to incorporate a wavefront sensor into the system to allow the reflected wavefronts to be analysed. The initial system was developed theoretically using a mathematical model and tested experimentally giving a high dynamic range (lOJlm - 8mm) and good accuracy (50nm) for this application. Analysis of higher order aberration modes introduced by the film structure have been carried out in simulation and a robust algorithm fonnulated to measure film thickness and surface tilt simultaneously using a single measurement. The most prominent aberrations introduced by laminate layers were identified as tilt, defocus, astigmatism and coma and monitoring of these modes allowed thickness variation to be measured. Experiments and simulations were shown to agree and further development of a sensor based on analysis of the interference between wavefronts allowed much thinner laminates to be measured. This work will allow further development of an industrial thickness monitor capable of measuring film thickness and surface fonn in multiple laminates simultaneously and suitable for in-line in-situ real time measurements.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available