3-dimensional control over lamella orientation and order in thick block copolymer films

Olszowka, Violetta; Tsarkova, Larisa; Böker, Alexander

doi:10.1039/b814365j

Cited by 49 publications

(70 citation statements)

References 38 publications

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“…55 The equilibrium thickness of an in-plane lamella is proportional to (0.5+n) L 0 , which amounts to approximately 75 nm for 1.5L 0 -thick SV films, consistent with the observed h crit . Both films have been exposed to 80% of p/p o in order to reach h crit .…”

Section: Resultssupporting

confidence: 60%

“…21 Analysis of the phase behavior under controlled solvent vapor treatment allowed to gain important insights into the mechanisms of microphase separation of conjugated polymers, 5 and of microdomain reorientation and ordering under combined application of solvent annealing and of electric field. [55][56][57][58] Furthermore, confinement effects on the microphase separation and swelling of thin 24,59 and thick 55,37 block copolymer films have become evident in the thickness-dependent swelling as well as in heterogeneous swelling of block copolymer films. 24,60,61 In the last years similar climate-controlled solvent-vapor annealing devices have been adopted and successfully exploited by several research groups.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing Ordering Dynamics in Solvent-Annealed Block Copolymer Films by Lithographic Hard Mask Supports

2014

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We studied solvent-driven ordering dynamics of block copolymer films supported by a densely cross-linked polymer network designed as organic hard mask (HM) for lithographic fabrications.The ordering of microphase separated domains at low degrees of swelling corresponding to intermediate/strong segregation regimes was found to proceed significantly faster in films on a HM layer as compared to similar block copolymer films on silicon wafers. The ten-fold enhancement of the chain mobility was evident in the dynamics of morphological phase transitions and of related process of terrace-formation on a macroscale, as well as in the degree of long-range lateral order of nanostructures. The effect is independent of the chemical structure and on the volume composition (cylinder-/ lamella-forming) of the block copolymers. In-situ ellipsometric measurements of the swelling behavior revealed a cumulative increase in 1-3 vol.2 % in solvent up-take by HM-block copolymer bilayer films, so that we suggest other than dilution effect reasons for the observed significant enhancement of the chain mobility in concentrated block copolymer solutions. Another beneficial effect of the HM-support is the suppression of the film dewetting which holds true even for low molecular weight homopolymer polystyrene films at high degrees of swelling. Apart from immediate technological impact in block copolymer-assisted nanolithography, our findings convey novel insight into effects of molecular architecture on polymer-solvent interactions.

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Section: Resultssupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Enhancing Ordering Dynamics in Solvent-Annealed Block Copolymer Films by Lithographic Hard Mask Supports

2014

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“…64 While the lamellae oriented parallel to the substrate in the ranges of film thicknesses, d < 19 and d > 23, a perpendicular orientation in the range 19 ≤ d ≤ 22 was observed. 64 At a first sight, this experimental observation seems to be in contradiction to our results. However, these experiments were done in the presence of a solvent that changed the degree of swelling of the BCP film.…”

Section: Discussionmentioning

confidence: 96%

“…It has been found that in the presence of a solvent the degree of swelling φ = λ e /λ s (where λ s stands for the lamellae period in the swollen state) depends on the film thickness. 64 For very thin films (d ≈ 3) the degree of swelling is around φ ≈ 0.68 whereas for thicker films (d ≈ 30) it is about φ ≈ 0.715, which means, thicker films swell about 4% less than thinner films and the concentration of the solvent c s is decreasing with increasing the film thickness. Accordingly, for thinner films in the swollen state we calculate an "effective value" of the model parameter α ∼ λ −4 : α s = (0.68) 4 α 0 (α 0 indicates the interaction parameter in the absence of a solvent).…”

Section: Discussionmentioning

confidence: 99%

Stability and orientation of lamellae in diblock copolymer films

Weith

Krekhov

Zimmermann

2013

The Journal of Chemical Physics

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The dynamics of microphase separation and the orientation of lamellae in diblock copolymers is investigated in terms of a mean-field model. The formation of lamellar structures and their stable states are explored and it is shown that lamellae are stable not only for the period of the structure corresponding to the minimum of the free energy. The range of wavelengths of stable lamellae is determined by a functional approach, introduced with this work, which is in agreement with the results of a linear stability analysis. The effects of the interaction of block copolymers with confining plane boundaries on the lamellae orientation are studied by an extensive analysis of the free energy. By changing the surface property at one boundary, a transition from a preferentially perpendicular to a parallel lamellar orientation with respect to the boundaries is found, which is rather independent of the distance between the boundaries. Computer simulations reveal, that the time scale of the lamellar orientational order dynamics, which is quantitatively characterized in terms of an orientational order parameter and the structure factor, depends significantly on the properties of the confining boundaries as well as on the quench depth.

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“…4 Therefore, tailoring of film structures is a very active area of the current research. External fields, such as electric 2,[5][6][7] and shear flow, 1,5 are instruments often used for structure manipulation.…”

Section: Introductionmentioning

confidence: 99%

Diblock copolymer sphere morphology in ultra thin films under shear

et al. 2011

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We demonstrate that the shear alignment and the shear-induced transitions in sphere-forming diblock copolymer single layer and bilayer films observed experimentally [Y.-R Hong, D. H. Adamson, P. M. R. A. Register, Soft Matter, 2009, 5, 1687] can be explained by cell dynamics simulation, a simple model with a Ginzburg-Landau Hamiltonian. In two layer films the spheres align in various arrangements, like (100) or (110) bcc planes, or transform to cylinders depending on the shear rate and the temperature. For the first time, we present a nontrivial alignment mechanism of a single layer of spherical domains in shear via slug-like movement of transient cylindrical micelles. In addition, we clarify the formation of the perpendicular cylinders, found in the recent particle based simulation [A. Chremos, K. Margaritis, A. Z. Panagiotopoulos, Soft Matter, 2010, 6, 3588].

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3-dimensional control over lamella orientation and order in thick block copolymer films

Cited by 49 publications

References 38 publications

Enhancing Ordering Dynamics in Solvent-Annealed Block Copolymer Films by Lithographic Hard Mask Supports

Enhancing Ordering Dynamics in Solvent-Annealed Block Copolymer Films by Lithographic Hard Mask Supports

Stability and orientation of lamellae in diblock copolymer films

Diblock copolymer sphere morphology in ultra thin films under shear

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