Simulation of Defect Reduction in Block Copolymer Thin Films by Solvent Annealing

Hur, Su-Mi; Khaira, Gurdaman; Ramírez-Hernández, Abelardo; Müller, Marcus; Nealey, Paul F.; Pablo, Juan

doi:10.1021/mz500705q

Cited by 79 publications

(121 citation statements)

References 43 publications

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“…The largest grain sizes were obtained in films that were annealed at solvent concentrations close to the order–disorder transition (ODT). Recent simulations of SVA in lamellar BCPs show that the defect density can be further reduced by first driving the film into the disordered state in order to efficiently remove processing‐related defects before annealing the BCP at solvent concentrations below (but close to) the ODT …”

Section: Introductionmentioning

confidence: 99%

An in situ GISAXS study of selective solvent vapor annealing in thin block copolymer films: Symmetry breaking of in‐plane sphere order upon deswelling

Gunkel

Sun

et al. 2015

J Polym Sci B Polym Phys

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Thin films of asymmetric poly(styrene-b-4-vinylpyridine) (PS-b-P4VP) block copolymers are studied by means of in situ grazing-incidence small-angle X-ray scattering (GISAXS) during solvent vapor annealing in tetrahydrofuran, a solvent selective for the PS majority block of the copolymer. Upon swelling, PS-b-P4VP block copolymers form hexagonal arrays of spherical P4VP microdomains in a PS matrix in films 7-9 layers thick. Deswelling the films induces a transition from hexagonal to face-centered orthorhombic (fco) symmetry, which is stable only at 7 layers of spherical microdomains. Dry films show co-existing hexagonal and orthorhombic symmetries when the solvent is removed slowly, whereas instantaneous solvent removal suppresses the fco structure, resulting in films with only hexagonal structure. The in-plane order of microdomains is significantly deteriorated in dry films independent of the solvent removal rate.Spherical block copolymer microdomains are known to undergo a transition from hexagonal to orthorhombic packing in isothermally annealed thin films when the number of sphere layers is increased from 4 to 5. In this paper, in situ GISAXS experiments reveal that a similar transition occurs during solvent vapor annealing in a selective solvent. Interestingly, the transition from hexagonal to orthorhombic packing of spheres occurs as solvent is removed from a thin block copolymer film.

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Section: Introductionmentioning

confidence: 99%

An in situ GISAXS study of selective solvent vapor annealing in thin block copolymer films: Symmetry breaking of in‐plane sphere order upon deswelling

Gunkel

Sun

et al. 2015

J Polym Sci B Polym Phys

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“…Also note that recent studies indicate that results for solvent annealing can be mapped onto those of thermal annealing (10) through the proper renormalization of material parameters (11). Fig.…”

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confidence: 97%

“…The results of simulations are validated through comparison with detailed images from fully 3D, transmission-electron-microscopy (TEM) tomography in thin copolymer films. We conclude this introductory section by noting that although our focus is thermal annealing, a future study will consider the more specialized problem of how thermal pathways can be altered (or not) through controlled addition of solvents (11,15,16).…”

mentioning

confidence: 99%

Molecular pathways for defect annihilation in directed self-assembly

Hur

Thapar

Ramírez-Hernández

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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140

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Over the last few years, the directed self-assembly of block copolymers by surface patterns has transitioned from academic curiosity to viable contender for commercial fabrication of nextgeneration nanocircuits by lithography. Recently, it has become apparent that kinetics, and not only thermodynamics, plays a key role for the ability of a polymeric material to self-assemble into a perfect, defect-free ordered state. Perfection, in this context, implies not more than one defect, with characteristic dimensions on the order of 5 nm, over a sample area as large as 100 cm 2 . In this work, we identify the key pathways and the corresponding free energy barriers for eliminating defects, and we demonstrate that an extraordinarily large thermodynamic driving force is not necessarily sufficient for their removal. By adopting a concerted computational and experimental approach, we explain the molecular origins of these barriers and how they depend on material characteristics, and we propose strategies designed to overcome them. The validity of our conclusions for industrially relevant patterning processes is established by relying on instruments and assembly lines that are only available at state-of-the-art fabrication facilities, and, through this confluence of fundamental and applied research, we are able to discern the evolution of morphology at the smallest relevant length scales-a handful of nanometers-and present a view of defect annihilation in directed self-assembly at an unprecedented level of detail.directed self-assembly | copolymer | defect | minimum free energy path | string method O ver the last decade, the directed self-assembly (DSA) of block copolymers has rapidly evolved from mere intellectual curiosity (1-4) to a potentially crucial step in the commercial fabrication of next-generation electronic circuits. Indeed, the characteristic length scale of ordered self-assembled copolymer domains is in the range of 5-50 nm. Furthermore, their size and shape can be manipulated through simple processing steps, thereby making them attractive for the production of semiconductor devices, nanofluidic devices, or high-density storage media (5, 6). The general idea behind copolymer DSA is that a surface patternchemical or topographic-can be used to guide the assembly of a polymeric material into an ordered, device-like structure that is free of defects. In so-called "density multiplication" patterning strategies (7,8), the spacing or pitch of the surface features can be much larger than the characteristic dimensions of the copolymer of interest. One can thus prepare coarse surface patterns, which are easier to create, and rely on the copolymer to self-assemble into features whose density is considerably larger. Fig. 1 shows a schematic representation of the process for obtaining a lamellar morphology on a stripe-patterned substrate under a one-to-three (or 3X) density multiplication strategy. Patterned stripes interact preferentially with one of the blocks and guide the assembly of thin copolymer films into ordered lam...

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“…43 The polydispersity can be minimized via synthetic control, 44 the degree of phase separation is determined by the segregation strength χN, and the BCP film morphology can be contolled by the annealing conditions. 45 It is also noted that the swelling ratio of the films during the annealing process is subject to room-temperature fluctuations, 33 where the swelling ratio can change from 1.8 to 2.0 ( Figure S2). Therefore, differences in the swelling ratio of films between subsequent layers may change the dot morphology and spacing.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Sequential Nanopatterned Block Copolymer Self-Assembly on Surfaces

Jin

Olsen

et al. 2016

Langmuir

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/acs.langmuir.6b01365Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Sequential nanopatterned block copolymer self-assembly on surfaces Jin, Cong; Olsen, Brian C.; Wu, Nathanael L. Y.; Luber, Erik J.; Buriak, Jillian M.http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/droits L'accès à ce site Web et l'utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D'UTILISER CE SITE WEB. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=ae78d03e-4423-4de5-89fb-823bb3c0676b http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=ae78d03e-4423-4de5-89fb-823bb3c0676bSequential Nanopatterned Block Copolymer Self-Assembly on Surfaces ABSTRACT: Bottom-up self-assembly of high-density blockcopolymer nanopatterns is of significant interest for a range of technologies, including memory storage and low-cost lithography for on-chip applications. The intrinsic or native spacing of a given block copolymer is dependent upon its size (N, degree of polymerization), composition, and the conditions of selfassembly. Polystyrene-block-polydimethylsiloxane (PS-b-PDMS) block copolymers, which are well-established for the production of strongly segregated single-layer hexagonal nanopatterns of silica dots, can be layered sequentially to produce density-doubled and -tripled nanopatterns. The center-tocenter spacing and diameter of the resulting silica dots are critical with respect to the resulting double-and triple-layer assemblies because dot overlap reduces the quality of the resulting pattern. The addition of polystyrene (PS) homopolymer to PS-b-PDMS reduces the size of the resulting silica dots but leads to increased disorder at higher concentrations. The quality of these density-multiplied patterns can be calculated and predicted using parameters easily derived from SEM micrographs of corresponding single...

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Simulation of Defect Reduction in Block Copolymer Thin Films by Solvent Annealing

Cited by 79 publications

References 43 publications

An in situ GISAXS study of selective solvent vapor annealing in thin block copolymer films: Symmetry breaking of in‐plane sphere order upon deswelling

An in situ GISAXS study of selective solvent vapor annealing in thin block copolymer films: Symmetry breaking of in‐plane sphere order upon deswelling

Molecular pathways for defect annihilation in directed self-assembly

Sequential Nanopatterned Block Copolymer Self-Assembly on Surfaces

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