title: Post-directed-self-assembly membrane fabrication for in situ analysis of block copolymer structures.
abstract: Full characterization of the three-dimensional structures resulting from the directed self-assembly (DSA) of block copolymers (BCP) remains a difficult challenge. Transmission electron microscope (TEM) tomography and resonant soft x-ray scattering have emerged as powerful and complementary methods for through-film characterization; both techniques require samples to be prepared on specialized membrane substrates. Here we report a generalizable process to implement BCP DSA with density multiplication on silicon nitride membranes. A key feature of the process developed here is that it does not introduce any artefacts or damage to the polymer assemblies as DSA is performed prior to back-etched membrane formation. Because most research and applications of BCP lithography are based on silicon substrates, process variations introduced by implementing DSA on a silicon nitride/silicon stack versus silicon were identified and mitigated. Using full-wafers, membranes were fabricated with different sizes and layouts to enable both TEM and x-ray characterization. Finally, both techniques were used to characterize structures resulting from the DSA of lamella-forming BCP with density multiplication.
authors.affiliation: University of Chicago, Institute for Molecular Engineering, 5640 S Ellis Ave ERC 229, Chicago, IL 60637, USA.
authors.forename: J
authors.initials: J
authors.lastname: Ren
authors.forename: L E
authors.initials: LE
authors.lastname: Ocola
authors.forename: R
authors.initials: R
authors.lastname: Divan
authors.forename: D A
authors.initials: DA
authors.lastname: Czaplewski
authors.forename: T
authors.initials: T
authors.lastname: Segal-Peretz
authors.forename: S
authors.initials: S
authors.lastname: Xiong
authors.forename: R J
authors.initials: RJ
authors.lastname: Kline
authors.forename: C G
authors.initials: CG
authors.lastname: Arges
authors.forename: P F
authors.initials: PF
authors.lastname: Nealey