title: Subtractive patterning via chemical lift-off lithography.
abstract: Conventional soft-lithography methods involving the transfer of molecular "inks" from polymeric stamps to substrates often encounter micrometer-scale resolution limits due to diffusion of the transferred molecules during printing. We report a "subtractive" stamping process in which silicone rubber stamps, activated by oxygen plasma, selectively remove hydroxyl-terminated alkanethiols from self-assembled monolayers (SAMs) on gold surfaces with high pattern fidelity. The covalent interactions formed at the stamp-substrate interface are sufficiently strong to remove not only alkanethiol molecules but also gold atoms from the substrate. A variety of high-resolution patterned features were fabricated, and stamps were cleaned and reused many times without feature deterioration. The remaining SAM acted as a resist for etching exposed gold features. Monolayer backfilling into the lift-off areas enabled patterned protein capture, and 40-nanometer chemical patterns were achieved.
authors.affiliation: California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA.
authors.forename: Wei-Ssu
authors.initials: WS
authors.lastname: Liao
authors.forename: Sarawut
authors.initials: S
authors.lastname: Cheunkar
authors.forename: Huan H
authors.initials: HH
authors.lastname: Cao
authors.forename: Heidi R
authors.initials: HR
authors.lastname: Bednar
authors.forename: Paul S
authors.initials: PS
authors.lastname: Weiss
authors.forename: Anne M
authors.initials: AM
authors.lastname: Andrews