marco rolandi, itai suez, hongjie dai, jean m. j. frechet u c berkeley , l.b.l. and stanford
DESCRIPTION
Dendrimer M onolayers A s N egative & P ositive T one R esists F or S canning P robe L ithography. Marco Rolandi, Itai Suez, Hongjie Dai, Jean M. J. Frechet U C Berkeley , L.B.L. and Stanford NANO LETTERS . 2004 V ol. 4, No. 5 889-893. Presented by Liang Pan. - PowerPoint PPT PresentationTRANSCRIPT
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Dendrimer Monolayers As Negative & Positive Tone Resists For Scanning Probe LithographyMarco Rolandi, Itai Suez, Hongjie Dai, Jean M. J. Frechet
UC Berkeley, L.B.L. and Stanford
NANO LETTERS. 2004 Vol. 4, No. 5 889-893
Presented by Liang Pan
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Many things need to be improved including resists
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Limitation of Conventional Resist for sub-10nm resolution
Chemical amplification help to increase the sensitivity (need fewer photons to initiate reaction), but resolution of most of conventional PR is limited by diffusion process of radical reactions.
Example*: Deprotection scheme.
This PR was used for DRAMs fabrications in IBM.
* IBM J of R&D. Volume 41, Numbers 1/2, 1997 Optical lithography
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New Scheme using Monolayer Resist Monolayer resist by self-
assembly techniques. Provides nanometer thick
and uniform resist layer over large area
Good etching resistance Photon/Electron harvesting
structure Greatly increases sensitivity
without diffusion process
Monolayer by self-assembly
Light-harvesting structure*
* M. Oar et al. Chem. Mater. 2006, 18, 3682-3692
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Dendrimer Monolayers Structures*
* M. Rolandi et al. NANO LETTERS. 2004 Vol. 4, No. 5 889-893
Dendrimer MoleculesIt takes about 30 minutes for the self-assembly process to finish in solution
Anchor
Antenna
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SPL ProcessUsing (not limited by) AFM
* M. Rolandi et al. NANO LETTERS. 2004 Vol. 4, No. 5 889-893
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Lithography Results
Positive Tone Negative Tone
* M. Rolandi et al. NANO LETTERS. 2004 Vol. 4, No. 5 889-893
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Related Works* about Self-Assembly Patterns
In another work, they broke down some bonds using AFM, and then selectively assembled different end-groups to do self-assembly lithography.
* S. Backer et al. Langmuir 2007, 23, 2297-2299
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Assembly Results
After exposing to end-groups solution for 12~24 h in a dry nitrogen environment, etching masks were generated by self-assembly.
* S. Backer et al. Langmuir 2007, 23, 2297-2299
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Summary The authors have devised new scanning probe
lithography schemes based on a self-assembled monolayer resists.
They demonstrated formation of both negative and positive tone pattern transfer.
Currently, only 20nm resolutions were demonstrated due to the limitation of AFM tips sharpness.
They claimed that dendrimer resists is possible to push lithographic resolution to a few nanometers.
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Thank you!
Questions?