Heat transfer properties of laser assisted plasma processing

dc.contributor.advisorJourdain, Renaud
dc.contributor.advisorShore, Paul
dc.contributor.authorParkins, Jonathon
dc.date.accessioned2013-03-13T15:18:26Z
dc.date.available2013-03-13T15:18:26Z
dc.date.issued2012-08
dc.description.abstractLaser assisted plasma processing (LAPP) is a novel extension to already established Reactive Atom Plasma (RAP) processing for atmospheric pressure dry chemical etching of silicon based materials; this is mainly applied for optical uses. The development of the new technology involves the implementation of an additional laser energy beam to tune the thermal footprint of the hybrid tool. This will influence the temperature-dependent etching reaction. The aim of the project was to develop a model to predict the temperature footprint of components of the LAPP tool and assess the suitability of this model in simulating the thermal effects during an actual process. This was undertaken via two routes: model development and experimental temperature investigation. The two materials investigated were Corning Ultra Low Expansion glass (ULE) and also Silicon Carbide (SiC). The model was developed using Matlab from an established analytical method and evolved for LAPP use. An analytical method based on a Green’s function solution to the heat equation for a moving Gaussian heat source on a surface was chosen as it would be an adaptable and rapid alternative to costly experimental measurements for LAPP. Experimental temperature measurements were investigated using pyrometers, resistance temperature detectors and thermocouples. Typical LAPP process parameters were investigated for both a laser source and a RAP torch, and the temperature was measured. Additionally, surface reflectivity was measured for appropriate wavelengths for LAPP applications using a Fourier transform infrared spectrometer to determine the absorbed portion of laser energy. The experimental work conducted using RTDs found strong correlation with the modelling, with 63% of results matching within experimental error. The pyrometer measurements were less successfully replicated, the reason for which is expected to be the cooling of the substrate from its upper surface not being accounted for in the model. Overall trends of temperature rise decreasing with increasing feed speed or decreasing power were observed. Thermocouple characterisation of the RAP torch was approximated using the radiative model.en_UK
dc.identifier.urihttp://dspace.lib.cranfield.ac.uk/handle/1826/7857
dc.language.isoenen_UK
dc.publisherCranfield Universityen_UK
dc.rights© Cranfield University 2011. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright owner.en_UK
dc.titleHeat transfer properties of laser assisted plasma processingen_UK
dc.typeThesis or dissertationen_UK
dc.type.qualificationlevelMastersen_UK
dc.type.qualificationnameMSc by Researchen_UK

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