Development of Reusable, Flexible Electrostatic Lenses for Nanopantography

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dc.contributor.advisorRuchhoeft, Paul
dc.contributor.committeeMemberLitvinov, Dmitri
dc.contributor.committeeMemberBao, Jiming
dc.contributor.committeeMemberDonnelly, Vincent M.
dc.contributor.committeeMemberEconomou, Demetre J.
dc.creatorBasu, Prithvi
dc.date.accessioned2021-08-04T01:33:25Z
dc.date.createdAugust 2020
dc.date.issued2020-08
dc.date.submittedAugust 2020
dc.date.updated2021-08-04T01:33:27Z
dc.description.abstractNanopantography is a method for forming large arrays of nano-sized patterns using a broad beam of ions. In this process, a near-monochromatic ion beam illuminates an array of micron-scale electrostatic lenses, and ions entering each lens converge to a small focal point on the substrate. By tilting the substrate with respect to the ion beam, the spot can be moved across the surface to write a periodic pattern. In a previous demonstration, openings as small as 3 nm in diameter were etched into silicon using a lens array containing 300 nm diameter lenses, creating a fairly straight-forward path to defining nano-scale patterns from much larger structures. Lenses previously consisted of a silicon dioxide dielectric layer sandwiched between a metal lens array and the silicon wafer, and so they were not re-useable, and patterns could only be etched into silicon. To make the system more flexible, we are developing removable and reusable electrostatic lenses that are designed to pattern any conducting surface. Our lenses consist of a free-standing epoxy (SU-8) membrane with etched openings and an electrode on one side. We have successfully etched 30 nm features using removable lenses and carried out simulations that agree with the experimental results. In order to manufacture the lenses, we used the helium atom beam lithography tool to pattern the lens substrates. The helium atom beam lithography tool uses stencil masks for patterning, and manufacturing these stencil masks is another aspect of this project. We are using 250 nm free-standing SU-8 membranes to make lithography masks and at first we are using copper as a hard mask to fabricate these masks. This process involves ion milling of the copper using an argon plasma and this led to an increase in the linewidth of the etched features into SU-8. In order to overcome this challenge, we shifted to using tungsten as a hard mask and the tungsten was reactive ion etched using SF6 plasma. We have demonstrated that we can form stencil masks with 50 nm, 75 nm and 100 nm etched openings with tungsten as the hard mask.
dc.description.departmentElectrical and Computer Engineering, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/10657/7963
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectNanopantography, Stencil Masks
dc.titleDevelopment of Reusable, Flexible Electrostatic Lenses for Nanopantography
dc.type.dcmiText
dc.type.genreThesis
local.embargo.lift2022-08-01
local.embargo.terms2022-08-01
thesis.degree.collegeCullen College of Engineering
thesis.degree.departmentElectrical and Computer Engineering, Department of
thesis.degree.disciplineElectrical Engineering
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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