title: SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography.
abstract: A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed.
authors.affiliation: Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4, Canada. M.A.Mohammad@ualberta.net.
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Mohammad
authors.forename: Steven K
authors.initials: SK
authors.lastname: Dew
authors.forename: Maria
authors.initials: M
authors.lastname: Stepanova