Research ArticleAPPLIED SCIENCES AND ENGINEERING

Polymeric lithography editor: Editing lithographic errors with nanoporous polymeric probes

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Science Advances  09 Jun 2017:
Vol. 3, no. 6, e1602071
DOI: 10.1126/sciadv.1602071
  • Fig. 1

    (A) An SEM image showing a cross section of a single track-etched pore in a glass substrate. (B) A typical SEM image of a single PDMS PLE fabricated using a conical pore as a template. The tip diameter (dt), base diameter (db), and height (h) of the PLE are 500 ± 100 nm, 22 ± 1 μm, and 38 ± 1 μm, respectively. This was an exact replica of the agarose PLE because both PLEs are synthesized from the same template. (C) A typical SEM image of the cross section of the agarose PLE shows nanochannels in the agarose matrix, which allowed adsorption and transport of the molecules from the patterns during the erasing process. (D) An SEM image of the agarose PLE showing nanochannels at the surface. Inset shows corresponding AFM image of the agarose surface.

  • Fig. 2

    (A) A schematic of the custom-built PLE system with an XYZ stage coupled to an inverted optical microscope. (B) Linear de-Embedded Image dependence suggested diffusion-based molecular erasing by the agarose PLE. The error bars in (B) is SD in de (n = 3). (C) A schematic representation of the absorption of molecules upon contact with the PLE tip with a contact time (te) of ~ 1.8 s. (D) A fluorescence micrograph of the PLE erasing with a 5% (w/w) of agarose after gelation. The diameter of the erased patterns was 11.7 ± 0.7 μm. (E) Deposition with agarose PLE—a continuous line deposition, with agarose PLE equilibrated in a 2% fluorescein solution. Scale bars, 30 μm (D and E). (F) A schematic showing the line pattern deposition of fluorescein using agarose encapsulated with fluorescein. Both the deposition and erasing occurred via the water meniscus formed upon contact between the conical hydrogel tip and the substrate.

  • Fig. 3

    (A) A schematic of the vdW interactions between the PLE and fluorescein-coated surfaces. Both the PLE and the glass were modeled as flat surfaces covered with a layer of water at its interface with air. The thicknesses of the water layers (T and T′) were varied in our calculations to accommodate for the changes in the RH of the atmosphere. (B) E-D dependence for the PLE glass interface. Here, E is the interaction energy due to vdW and capillary forces between the PLE tip and the substrate, and D is the PLE-surface distance.

  • Fig. 4 “Editing”—Write-erase-rewrite using PLE.

    (A) A 3 × 3 fluorescent array deposited using a PDMS PLE pen (dt = 500 nm, db = 22 μm, and h = 38 μm). (B to D) Partial consecutive erasing of patterns along the diagonal. (E) Complete erasing of the fluorescent dots along the diagonal. (F) Demonstration of the rectification process of the patterns. AU, arbitrary units. (G) A schematic of the agarose PLE erasing mechanism showing partial erasing. The optical micrographs of the PDMS PLE pen (H) and agarose PLE eraser (I) in contact with the surface, as seen through the microscope. Scale bars, 25 μm (H and I).

  • Fig. 5

    (A) An interdigitated copper electrode fabricated by redox reaction between the Cu0- and Fe3+-containing agarose PLE erasers. Scale bar, 150 μm. (B) A typical photoinduced current-time response for a device shown in (A). Black and yellow stars represent light turned OFF and ON, respectively.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/6/e1602071/DC1

    fig. S1. Erasing efficiency.

    fig. S2. Change in RH at the pattern-air interface.

    fig. S3. A large-scale conical agarose eraser.

    fig. S4. Optical micrograph of the PLE eraser.

    fig. S5. Patterns deposited by PDMS PLE pens with a tip of 500 nm.

    fig. S6. The schematic for the estimation of the capillary forces between the PLE and the surface.

    fig. S7. FDTD simulation and microscopic visualization of a PLE conical pen before and after contact.

    RH–versus–PLE substrate gap dependence

    Role of humidity in writing and erasing

    Mechanism of erasing

    Nature of force between the PLE and the substrate

    Capillary interactions for the PLE-surface pair

    FDTD analysis

    movie S1. This video was captured through the eyepiece of an inverted microscope while erasing the 6 × 6 array (Fig. 2D).

    movie S2. This video was captured through the eyepiece of an optical microscope under bright-field conditions.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Erasing efficiency.
    • fig. S2. Change in RH at the pattern-air interface.
    • fig. S3. A large-scale conical agarose eraser.
    • fig. S4. Optical micrograph of the PLE eraser.
    • fig. S5. Patterns deposited by PDMS PLE pens with a tip of 500 nm.
    • fig. S6. The schematic for the estimation of the capillary forces between the PLE and the surface.
    • fig. S7. FDTD simulation and microscopic visualization of a PLE conical pen before and after contact.
    • RH–versus–PLE substrate gap dependence
    • Role of humidity in writing and erasing
    • Mechanism of erasing
    • Nature of force between the PLE and the substrate
    • Capillary interactions for the PLE-surface pair
    • FDTD analysis
    • Legends for movies S1 and S2

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    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.mp4 format). This video was captured through the eyepiece of an inverted microscope while erasing the 6 × 6 array (Fig. 2D).
    • movie S2 (.mp4 format). This video was captured through the eyepiece of an optical microscope under bright-field conditions.

    Files in this Data Supplement: