1 / 13

Advancements in Nanoimprint Lithography: Utilizing Single-Walled Carbon Nanotubes as Templates

This presentation discusses innovative methods for imprinting nanoscale features into thin polymer films using molds. Emphasizing the use of single-walled carbon nanotubes (SWNTs) as templates, the evaluation of resolution limits highlights challenges in fabricating structures under 5nm. The fabrication process involves growth of SWNTs via CVD, followed by spin coating and UV curing techniques. Results from atomic force microscopy (AFM) and transmission electron microscopy (TEM) illustrate the successful replication of nanoscale features, while exploring polymer behavior and crosslink density's effect on resolution.

beyla
Télécharger la présentation

Advancements in Nanoimprint Lithography: Utilizing Single-Walled Carbon Nanotubes as Templates

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Jaehyun Park EE235 Student presentation / Mar 09, 2009

  2. Motivation • Among NGL methods : use molds for imprinting features into thin polymer films • Evaluation of resolution limits : most effectively done by using molds • Difficult to fabricate structures of sub 5nm using conventional methods : resolution limit and non-uniformities

  3. Their solution • Use SWNTs as templates • Features of SWNT (single-walled nanotube) • Cylindrical cross-sections • Atomic scale uniformity • Chemical inertness • Ability to grow or deposit them in large quantities over large areas : 0.5~5nm dia.,1~10 tubes/μm2 • Research on polymer characteristics with SWNT molds

  4. Fabrication process • Master mold : • Grow SWNT using CVD on SiO2/Si • Replicated mold : • Spin h-PDMS on cured PDMS • Casting & curing: Platinum catalyst used to form 3D crosslinking • Imprinting : • Spin low viscosity PU • Lightly press mold & cure under UV • Peel off

  5. Experiments : AFM • AFM Shows heights of features • Accurately reproduces nanoscale features over multiple cycles • Some distortions : surface roughness of molded PU

  6. Experiments : TEM TEM : mold • TEM shows widths of features • PAA used instead of PU • Imprinted structures similar to master features • For widths below 3nm : difficult to determine due to grain size of Pt/C (~1nm) TEM : master

  7. Experiments : AFM at sub 2nm scale • defects appeared

  8. Polymer limits resolution • Clues • Beaks in molded feature occurs at the same position • Imprinted features with dissimilar polymers have similar surface roughness • SiO2/Si has 0.19nm surface roughness • Distance between crosslinks of polymer (1nm for h-PDMS)

  9. Density of crosslinks • Crosslink density : affects capability of defining small feature and retaining shape • Attempts to increase in h-PDMS : failed due to stiction to mater mold

  10. Surface roughness • F. Hua, et. al., “Processing Dependent Behavior of Soft Imprint Lithography on the 1-10 nm Scale”, IEEE Trans. on Nanotechnology, 5, 301 (2006) • Got 0.26nm RMS at 9k rpm of polymer spin • Processing conditions : extremely important in achieving high-fidelity nanoimprint lithography in the 1-10nm regime.

  11. Conclusion • Simple method for evaluating resolution limits on imprinting polymers, as small as 2nm • Resolution is determined by both polymer chemistry and process condition • To enhance the resolution • Polymer having high crosslink density • Process to make smaller roughness

  12. Supplements : TEM • TEM analysis for lateral dimension • Sample prepared by metal shadowing technique • PAA can replicate fine feature and is dissolvable by water • Pt/C has fine grain • Carbon mechamically support the thin film

  13. Supplements : Pt catalyst

More Related