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Templated self-assembly for complex pattern fabrication

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 147-157). / The long-term goal of my Ph.D. study has been controlling the self-assembly of various materials using state-of-the-art nanofabrication techniques. Electron-beam lithography has been used for decades to generate nanoscale patterns, but its throughput is not high enough for fabricating sub-10-nm patterns over a large area. Templated block copolymer(BCP) self assembly is attractive for fabricating few-nanometer-scale structures at high throughput. On an unpattermed substrate, block copolymer self-assembly generates dense arrays of lines or dots without long-range order. Fortunately, physical features defined by electron lithography can guide the self-assembly of block copolymer. In our previous work, the orientation of cylindrical phase block copolymer was controlled simply by changing the distance between physical features, and resulting polymer patterns were analyzed by an image analysis program. Here, we first demonstrated high throughput sub-10-nm feature sizes by applying the same approach to a cylindrical morphology 16kg/mol PS-PDMS block copolymer. The half-pitch of the PDMS cylinders of this block copolymer film is 9 nm, so sub-10-nm structures can be fabricated. We also applied the similar approach to a triblock terpolymer to achieve dot patterns with square symmetry. To achieve a more complex pattern, electron-beam induced cross-linking of a block copolymer and second solvent-annealing process was used. By using this method, a line-dot hybrid pattern was achieved. Despite that the block copolymer self-assembly area had been heavily studied, researchers had yet to ascertain how to design nanostructures to achieve a desired target pattern using block copolymers. To address this problem, we developed a modular method that greatly simplifies the nanostructure design, and using this method, we achieved a circuit-like block-copolymer pattern over a large area. The key innovation is the use of a binary set of tiles that can be used to very simply cover the desired patterning area. Despite the simplicity of the approach, by exploiting neighbor-neighbor interactions of the tiles, a complex final pattern can be formed. The vision is thus one of programmability of patterning by using a simple instruction set. This development will thus be of interest to scientists and engineers across many fields involving self-assembly, including biomolecule, quantum-dot or nanowire positioning; algorithmic self-assembly; and integrated-circuit development. We applied this concept - controlling the assembly of materials using nanostructures - to a different material, protein. Single-molecule protein arrays are useful tools for studying biological phenomena at the single-molecule level, but have been developed only for a few specific proteins using the streptavidin-biotin complex as a linker. By using carefully designed gold nanopatterns and cysteine-gold interaction, we developed a process to make single-molecule protein arrays that can be used for patterning a broad range of proteins. / by Jae-Byum Chang. / Ph. D.

Identiferoai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/88368
Date January 2014
CreatorsChang, Jae-Byum
ContributorsKarl K. Berggren., Massachusetts Institute of Technology. Department of Materials Science and Engineering., Massachusetts Institute of Technology. Department of Materials Science and Engineering.
PublisherMassachusetts Institute of Technology
Source SetsM.I.T. Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Format157 pages, application/pdf
RightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582

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