title: 22-nm immersion interference lithography.
abstract: Immersion interference lithography was used to pattern gratings with 22-nm half pitch. This ultrahigh resolution was made possible by using 157-nm light, a sapphire coupling prism with index 2.09, and a 30-nm-thick immersion fluid with index 1.82. The thickness was controlled precisely by spin-casting the fluid rather than through mechanical means. The photoresist was a diluted version of a 193-nm material, which had a 157-nm index of 1.74. An analysis of the trade-off between fluid index, absorption coefficient, gap size and throughput indicated that, among the currently available materials, employing a high-index but absorbing fluid is preferable to using a highly transparent but low-index immersion media.
authors.forename: T M
authors.initials: TM
authors.lastname: Bloomstein
authors.forename: Michael F
authors.initials: MF
authors.lastname: Marchant
authors.forename: Sandra
authors.initials: S
authors.lastname: Deneault
authors.forename: Dennis E
authors.initials: DE
authors.lastname: Hardy
authors.forename: Mordechai
authors.initials: M
authors.lastname: Rothschild