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Block Copolymer Micelle Nanolithography Roman Glass, Martin Moller and Joachim P Spatz University of Heidelberg IOP Nano PowerPoint Presentation
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Block Copolymer Micelle Nanolithography Roman Glass, Martin Moller and Joachim P Spatz University of Heidelberg IOP Nano

Block Copolymer Micelle Nanolithography Roman Glass, Martin Moller and Joachim P Spatz University of Heidelberg IOP Nano

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Block Copolymer Micelle Nanolithography Roman Glass, Martin Moller and Joachim P Spatz University of Heidelberg IOP Nano

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  1. Block Copolymer Micelle NanolithographyRoman Glass, Martin Mollerand Joachim P SpatzUniversity of HeidelbergIOP Nanotechnology (2003) Erika Parra EE235 4/18/2007

  2. Motivation • Market Trends • Small features • Sub-10nm clusters deposited • Patterns 50nm to 250nm and greater • Lower cost of tedious fabrication processes for conventional lithography • Increase throughput (from e-beam) – parallel process • Bottom line: bridge gap between traditional self-assembly and lithography

  3. Process Overview • Dip wafer (Si) into micelle solution • Retrieve at 12mm/min • Air-evaporate solvent • Plasma (H2, Ar, or O2) removes polymer shell Results: • Uniform • Hexagonal • 2, 5, 6, or 8nm • Spherical PS(190)-b-P[2VP(Au0.2)](190) PS(500)-b-P[2VP(Au0.5)](270) PS(990)-b-P[2VP(Au0.5)](385) PS(1350)-b-P[2VP(Au0.5)](400) Side view TEM – treated wafer Au ~ HAuCl4

  4. Diblock Copolymer Micelles • Dendrite shaped macromolecule • Corona is amphiphilic • Micelle MW and shape controlled by initial monomer concentration • Polymer corona with “neutralized” core (Au, Ag, AgOx, Pt, Pd, ZnOx, TiOx, Co, Ni, and FeOx) • Nanodot “core” size is controlled by the amount of metal precursor salt PS P2VP Au • In this paper: • Water-in-oil micelle (toulene solvent) • Polystyrene(x)-b-poly(2-vinylpyridine)(y) (PS(x)-b-P2VP(y)) • Au core from chloroauric precursor (HAuCl4)

  5. Cluster Pattern Characterization • MW tunes nanodot distance (max of 200 nm micelle) • Low polydispersity permits regularity • Higher MW decreased pattern quality and position precision (softness in shell) Low PDI

  6. Guided Self-Assembly (>250nm) • Predefine topographies using photo or e-beam • Spin-on concentrated micelle solution (capillary forces of evaporating solvent adheres them to sides) • Micelles are pinned to the substrate by plasma (100W, 0.4mbar, 3min) • Lift-off removes PR and micelles • 2nd plasma treatment removes micelle polymer (100W, 0.4mbar, 20min) PS(1350)-b-P[2VP(Au0.5)](400) D = 8nm, L = 85nm

  7. Cluster Aggregation • Vary PR thickness • Feature height (volume) defines cluster diameter • Figure: e-beam 200nm features on 2um square lattice 800nm 500nm 75nm

  8. Line Patterning • Cylindrical micelle • Formed if corona volume fraction < core • PS(80)-b-P2VP(330) • Length of several microns • Substrate patterned with grooves & dipped in micelle solution 4nm line

  9. Negative Patterning with E-beam • Spin-on micelles • Expose with e-beam (1KeV, 400-50,000 μC/cm2), 200um width • Ultrasound bath + 30min plasma • Electrons stabilize micelle on Si due to carbon species formed during exposure

  10. Micelles on Electrically Insulating Films • Glass substrate desired in biology • E-beam requires conductive substrate • Evaporate 5nm carbon layer

  11. Mechanical Stability of Nano-Clusters • Treated and unaffected by: • Pirahna, acids, many bases, alcohols, ultrasonic water bath • Hypothesis: edge formed by the substrate-cluster borderline is partly wetted by surface atoms during plasma treatment • Thermal • 800 C evaporated clusters but no migration occured

  12. Conclusions • Simple process for sub-10nm clusters and lines • Block copolymer micelle size controls nano-cluster interspacing • Micelle size controlled by monometer concentrations Micelles as masks for diamond field emitters F. Weigl et al. / Diamond & Related Materials 15 (2006)