title: Directed Self-Assembly of Triblock Copolymer on Chemical Patterns for Sub-10-nm Nanofabrication via Solvent Annealing.
abstract: Directed self-assembly (DSA) of block copolymers (BCPs) is a leading strategy to pattern at sublithographic resolution in the technology roadmap for semiconductors and is the only known solution to fabricate nanoimprint templates for the production of bit pattern media. While great progress has been made to implement block copolymer lithography with features in the range of 10-20 nm, patterning solutions below 10 nm are still not mature. Many BCP systems self-assemble at this length scale, but challenges remain in simultaneously tuning the interfacial energy atop the film to control the orientation of BCP domains, designing materials, templates, and processes for ultra-high-density DSA, and establishing a robust pattern transfer strategy. Among the various solutions to achieve domains that are perpendicular to the substrate, solvent annealing is advantageous because it is a versatile method that can be applied to a diversity of materials. Here we report a DSA process based on chemical contrast templates and solvent annealing to fabricate 8 nm features on a 16 nm pitch. To make this possible, a number of innovations were brought in concert with a common platform: (1) assembling the BCP in the phase-separated, solvated state, (2) identifying a larger process window for solvated triblock vs diblock BCPs as a function of solvent volume fraction, (3) employing templates for sub-10-nm BCP systems accessible by lithography, and (4) integrating a robust pattern transfer strategy by vapor infiltration of organometallic precursors for selective metal oxide synthesis to prepare an inorganic hard mask.
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Shisheng
authors.initials: S
authors.lastname: Xiong
authors.affiliation: HGST, a Western Digital Company , San José, California 95135, United States.
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Ishida
authors.affiliation: HGST, a Western Digital Company , San José, California 95135, United States.
authors.forename: Yves-Andre
authors.initials: YA
authors.lastname: Chapuis
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Gordon S W
authors.initials: GS
authors.lastname: Craig
authors.affiliation: HGST, a Western Digital Company , San José, California 95135, United States.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Ruiz
authors.affiliation: Institute for Molecular Engineering, University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Nealey
keywords: ABA triblock copolymer; PS-b-P2VP; chemical contrast pattern; directed self-assembly; lithography; pattern transfer; solvent annealing