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Proceedings Paper

The value, solutions, and costs of patterning LEDs
Author(s): Michael P. C. Watts; M. Zoorob; T. Lee; J. McKenzie
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Paper Abstract

The literature on high brightness LED's shows that patterning the top surface of LED's with photonic crystals is being used to create the most intense LED light sources. The best example is that you can now buy projection displays that are illuminated by LED's with Photonic Crystals. The experimental and model data, reviewed in this article, shows that patterning delivers value through improved beam shaping and light extraction using carefully optimized photonic crystals. The data also suggests that in the future, patterning in combination with sub micron device layers and strategically placed mirrors can produce extraction efficiencies of greater than 80%. In addition, patterning can improve current spreading and reduce epitaxy defects. The long term goal is to develop a LED that can be used with minimal additional packaging to focus the light or extract heat. The solution to low cost patterning for Photonic Crystals 100 nm features is to use imprint. The imprint patterning process is implemented in a module that consists of a clean and coat tool, an imprint tool and an etch tool. Cleaning is essential because imprint is a contact technology and particles will lead to process defects and mold damage. There are 2 companies that are developing production tools for LED applications; Molecular Imprints (MII) and Obducat. There are 2 companies that are supporting research tools, and expect to develop production systems in response to customer order, EV Group and Nanonex. The principal difference between imprint suppliers are the different strategies used to conform the mold to the substrate, and the state of system development. To date MII has published the most complete process performance data on an automated production tool. The cost of patterning is less than 0.5 cent per device. First the value of increased LED output will be described, followed by a discussion of the different patterning solutions for improving output, then the different solutions for creating the patterning will be described and finally the costs are estimated.

Paper Details

Date Published: 7 March 2007
PDF: 12 pages
Proc. SPIE 6462, Micromachining Technology for Micro-Optics and Nano-Optics V and Microfabrication Process Technology XII, 64620N (7 March 2007); doi: 10.1117/12.711475
Show Author Affiliations
Michael P. C. Watts, Impattern Solutions (United States)
M. Zoorob, Mesophotonics Inc. (United Kingdom)
T. Lee, Mesophotonics Inc. (United Kingdom)
J. McKenzie, Mesophotonics Inc. (United Kingdom)

Published in SPIE Proceedings Vol. 6462:
Micromachining Technology for Micro-Optics and Nano-Optics V and Microfabrication Process Technology XII
Mary-Ann Maher; Thomas J. Suleski; Eric G. Johnson; Harold D. Stewart; Jung-Chih Chiao; Gregory P. Nordin, Editor(s)

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