title: Three-Tone Chemical Patterns for Block Copolymer Directed Self-Assembly.
abstract: Chemical patterns for directed self-assembly (DSA) of lamellae-forming block copolymers (BCP) with density multiplication can be fabricated by patterning resist on a cross-linked polystyrene layer, etching to create guide stripes, and depositing end-grafted brushes in between the stripes as background. To date, two-tone chemical patterns have been targeted with the guide stripes preferentially wet by one block of the copolymer and the background chemistry weakly preferentially wet by the other block. In the course of fabricating chemical patterns in an all-track process using 300 mm wafers, it was discovered that the etching process followed by brush grafting could produce a three-tone pattern. We characterized the three regions of the chemical patterns with a combination of SEM, grazing-incidence small-angle X-ray scattering (GISAXS), and assessment of BCP-wetting behavior, and evaluated the DSA behavior on patterns over a range of guide stripe widths. In its best form, the three-tone pattern consists of guide stripes preferentially wet by one block of the copolymer, each flanked by two additional stripes that wet the other block of the copolymer, with a third chemistry as the background. Three-tone patterns guide three times as many BCP domains as two-tone patterns and thus have the potential to provide a larger driving force for the system to assemble into the desired architecture with fewer defects in shorter time and over a larger process window.
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.|imec , Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: Lance D
authors.initials: LD
authors.lastname: Williamson
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.|imec , Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Seidel
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Xuanxuan
authors.initials: X
authors.lastname: Chen
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Hyo Seon
authors.initials: HS
authors.lastname: Suh
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.|imec , Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: Paulina
authors.initials: P
authors.lastname: Rincon Delgadillo
authors.affiliation: imec , Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: Roel
authors.initials: R
authors.lastname: Gronheid
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.|Material Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Lemont, Illinois 60439, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Nealey
keywords: block copolymer; chemical pattern; chemoepitaxy; directed self-assembly; surface modification