title: Quantitative Three-Dimensional Characterization of Block Copolymer Directed Self-Assembly on Combined Chemical and Topographical Prepatterned Templates.
abstract: Characterization of the three-dimensional (3D) structure in directed self-assembly (DSA) of block copolymers is crucial for understanding the complex relationships between the guiding template and the resulting polymer structure so DSA could be successfully implemented for advanced lithography applications. Here, we combined scanning transmission electron microscopy (STEM) tomography and coarse-grain simulations to probe the 3D structure of P2VP-b-PS-b-P2VP assembled on prepatterned templates using solvent vapor annealing. The templates consisted of nonpreferential background and raised guiding stripes that had PS-preferential top surfaces and P2VP-preferential sidewalls. The full 3D characterization allowed us to quantify the shape of the polymer domains and the interface between domains as a function of depth in the film and template geometry and offered important insights that were not accessible with 2D metrology. Sidewall guiding was advantageous in promoting the alignment and lowering the roughness of the P2VP domains over the sidewalls, but incommensurate confinement from the increased topography could cause roughness and intermittent dislocations in domains over the background region at the bottom of the film. The 3D characterization of bridge structures between domains over the background and breaks within domains on guiding lines sheds light on possible origins of common DSA defects. The positional fluctuations of the PS/P2VP interface between domains showed a depth-dependent behavior, with high levels of fluctuations near both the free surface of the film and the substrate and lower fluctuation levels in the middle of the film. This research demonstrates how 3D characterization offers a better understanding of DSA processes, leading to better design and fabrication of directing templates.
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.|Department of Chemical Engineering, Technion - Institute of Technology , Haifa 3200003, Israel.
authors.forename: Tamar
authors.identifier: 0000-0003-3222-6429
authors.initials: T
authors.lastname: Segal-Peretz
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Jiaxing
authors.initials: J
authors.lastname: Ren
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Shisheng
authors.initials: S
authors.lastname: Xiong
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Gurdaman
authors.initials: G
authors.lastname: Khaira
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Alec
authors.initials: A
authors.lastname: Bowen
authors.forename: Leonidas E
authors.identifier: 0000-0003-4990-1064
authors.initials: LE
authors.lastname: Ocola
authors.forename: Ralu
authors.initials: R
authors.lastname: Divan
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Manolis
authors.initials: M
authors.lastname: Doxastakis
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Ferrier
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Juan
authors.identifier: 0000-0002-3526-516X
authors.initials: J
authors.lastname: de Pablo
authors.affiliation: Institute for Molecular Engineering, University of Chicago , 5640 South Ellis Avenue, Chicago, Illinois 60637, United States.
authors.forename: Paul F
authors.identifier: 0000-0003-3889-142X
authors.initials: PF
authors.lastname: Nealey
keywords: P2VP-b-PS-b-P2VP; TEM tomography; block copolymer; defects; directed self-assembly; fluctuations