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Real-time feedback system for controlling the optical density of bimetallic thin-film grayscale photomasks

Resource type
Thesis type
(Thesis) M.A.Sc.
Date created
2010-12-20
Authors/Contributors
Author: Dykes, James
Abstract
Bimetallic grayscale photomasks consist of a bi-layer thin-film that is converted into a transparent oxide upon laser exposure. The film’s transparency is a function of the laser power allowing grayscale masks to be produced by controlling the laser’s intensity during the mask-writing process. The mask’s accuracy is determined by the control over the laser power. Using a direct-write raster-scanning system, a feedback-controlled design is created through the addition of photodiode sensors and an FPGA-based microprocessor subsystem allowing measurements of the mask’s transparency to control the laser’s power. When patterning mask lines ranging from 1.7 to 0.5 OD on a 100 nm Bi/In film using an 8-bit grayscale without OD feedback, the lines produced are accurate to ±0.02 OD for exposures
Document
Identifier
etd6392
Copyright statement
Copyright is held by the author.
Permissions
The author granted permission for the file to be printed and for the text to be copied and pasted.
Scholarly level
Supervisor or Senior Supervisor
Thesis advisor: Chapman, Glenn H.
Member of collection
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etd6392_JDykes.pdf 32.43 MB

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