title: The Limits of Lamellae-Forming PS-b-PMMA Block Copolymers for Lithography.
abstract: We explore the lithographic limits of lamellae-forming PS-b-PMMA block copolymers by performing directed self-assembly and pattern transfer on a range of PS-b-PMMA materials having a full pitch from 27 to 18.5 nm. While directed self-assembly on chemical contrast patterns was successful with all the materials used in this study, clean removal of PMMA domains and subsequent pattern transfer could only be sustained down to 22 nm full pitch. We attribute this limitation to the width of the interface, which may represent more than half of the domain width for materials with a critical dimension below 10 nm. With the limit of pattern transfer for PS-b-PMMA set at ∼11 nm, we propose an integration scheme suitable for bit patterned media for densities above 1.6 Tdot/in(2), which require features below this limit. Directed self-assembly was carried out on chemical contrast patterns made by a rotary e-beam lithography system, and pattern transfer was carried out to demonstrate fabrication of large area (up to 25 mm-wide annular band of circular tracks) nanoimprint templates for bit patterned media. We also demonstrate compatibility with hard disk drive architecture by fabricating patterns with skewed radial lines with constant angular pitch and with servo patterns that are needed in hard disk drives to generate a radial positional error signal (PES).
authors.affiliation: †HGST, A Western Digital Company, San Jose Research Center, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.affiliation: †HGST, A Western Digital Company, San Jose Research Center, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ruiz
authors.affiliation: †HGST, A Western Digital Company, San Jose Research Center, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors.forename: He
authors.initials: H
authors.lastname: Gao
authors.affiliation: †HGST, A Western Digital Company, San Jose Research Center, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors.forename: Kanaiyalal C
authors.initials: KC
authors.lastname: Patel
authors.affiliation: †HGST, A Western Digital Company, San Jose Research Center, 3403 Yerba Buena Road, San Jose, California 95135, United States.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Albrecht
authors.affiliation: ‡EMD Performance Materials Corp., 70 Meister Avenue, Somerville, New Jersey 08876, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Yin
authors.affiliation: ‡EMD Performance Materials Corp., 70 Meister Avenue, Somerville, New Jersey 08876, United States.
authors.forename: Jihoon
authors.initials: J
authors.lastname: Kim
authors.affiliation: ‡EMD Performance Materials Corp., 70 Meister Avenue, Somerville, New Jersey 08876, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.affiliation: ‡EMD Performance Materials Corp., 70 Meister Avenue, Somerville, New Jersey 08876, United States.
authors.forename: Guanyang
authors.initials: G
authors.lastname: Lin
keywords: PS-b-PMMA; bit-patterned media; block copolymer lithography; lamellae; nanoimprint template fabrication; pattern transfer; rotary e-beam lithography