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Ice Lithography (IL) is a new technique for electron beam lithography that employs conformal ices (i.e., solid phase condensed gasses) as sacrificial resist layers for lithographic processes on a variety of sample types. The completely dry in-situ processing inherent in IL allows for high precision patterning of delicate and organic surfaces such as atomic force microscope (AFM) tips and proteins. In this talk I will present an overview of the capabilities of the MU IL instrument and describe our recent work, which is centered on pushing ice species beyond water. Amorphous H2O ice is a material that has been well characterized in the astrophysics community but has received little attention from the nanotechnology field. It is a positive resist that requires large critical doses (about 2C/cm^2 for 200nm thick ice). The alcohols (ethanol, methanol and isopropanol) are attractive candidates to complement water ice. They are negative phase resists which exhibit lower critical dose (0.2C/cm^2 for 200nm thick ice) requirements than water ice. We are exploring the use of alcohol resists in conjunction with Reactive Ion Etching (RIE) for accurate modification of small, delicate, structures such as AFM tips. We are also interested in characterizing the residual material from alcohol ices after exposure to the electron beam which can be achieved through several methods including Electron Energy Loss Spectroscopy (EELS) and simulations such as the high energy chemistry program GEANT-4.
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Green Lithography for Delicate Materials
Abstract A variety of unconventional materials, including biological nanostructures, organic and hybrid semiconductors, as well as monolayer, and other low‐dimensional systems, are actively explored. They are usually incompatible with standard lithographic techniques that use harsh organic solvents and other detrimental processing. Here, a new class of green and gentle lithographic resists, compatible with delicate materials and capable of both top‐down and bottom‐up fabrication routines is developed. To demonstrate the excellence of this approach, devices with sub‐micron features are fabricated on organic semiconductor crystals and individual animal's brain microtubules. Such structures are created for the first time, thanks to the genuinely water‐based lithography, which opens an avenue for the thorough research of unconventional delicate materials at the nanoscale.
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- Award ID(s):
- 1806363
- PAR ID:
- 10450741
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 31
- Issue:
- 27
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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