Directed Self Assembly Of Block Copolymer Thin Films From Fundamentals Science To Applications
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Directed Self Assembly Of Block Copolymer Thin Films From Fundamentals Science To Applications
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Author :
language : en
Publisher:
Release Date : 2014
Directed Self Assembly Of Block Copolymer Thin Films From Fundamentals Science To Applications written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
In Chapter 4, the alignment of block copolymer domains in tapered width channels has been studied. Confined polymer chains undergo elastic deformation to satisfy the channel width constraint and narrow end of the channel imparts a stronger directing field on the alignment of block copolymer domains.
Directed Self Assembly Of Nanostructured Block Copolymer Thin Films Via Dynamic Thermal Annealing
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Author : Monali N. Basutkar
language : en
Publisher:
Release Date : 2018
Directed Self Assembly Of Nanostructured Block Copolymer Thin Films Via Dynamic Thermal Annealing written by Monali N. Basutkar and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Block copolymers categories.
The aggressive miniaturization of nanoelectronic devices poses a pressing challenge in using conventional patterning technologies that are fast approaching their intrinsic resolution limits. Molecular self-assembling block copolymers (BCPs) are promising candidates for integrating and extending the current photolithographic constraints, facilitating the fabrication of next-generation nanotemplating materials via directed self-assembly. The current work focuses on the development of viable dynamic self-assembly strategies for achieving highly ordered versatile BCP nanostructures with precise feature size control and registration, as well as provides insights into the fundamentals of BCP thin film self-assembly driven by dynamic annealing fields A continuous template-free method toward rapid fabrication (2-4 minutes) of highly ordered through-thickness vertical lamellar polystyrene-block-poly(methyl methacrylate) l-PS-b-PMMA) microdomains in l-BCP films on quartz (silicon oxide) substrate was developed. A molecular relaxation induced vertical l-BCP ordering occurs under a transient macroscopic vertical strain field, imposed by a high film thermal expansion rate under sharp thermal gradient cold zone annealing (CZA-S). The high thermal gradient had to be selectively tuned with the CZA-S sweep rates for controlling the polymer chain relaxation dynamics for vertical order. Comparable conventional static thermal annealing of identical l-BCP films using vacuum oven failed to induce the desired nanostructure. Morphology evolution tracked in real time along the CZA-S thermal gradient profile using in situ grazing incidence small angle x-ray scattering (GISAXS) demonstrated four regimes of ordering: microphase separation from a quenched-disordered state (Regime 1), initial formation of vertical lamellae due to the sharp thermal gradient imposed on the l-BCP film (Regime 2), polygrain structure resulting from the broad [del] T region around Tmax (Regime 3), and an ultimate highly vertically ordered l-BCP morphology due to grain coarsening on the cooling edge (Regime 4). A detailed examination of the influence of CZA process parameters such as temperature gradient field strength ([del] T) of the thermal annealing profile, sweep velocity (v) and the corresponding annealing time (t) on the mechanism and dynamics of l-BCP ordering was performed. The complex interplay between thermodynamic equilibrium, surface and interfacial energies, confinement effects and BCP ordering kinetics was also investigated to determine the effect of BCP film attributes on morphological development. By tuning the CZA-S process dynamics with the l-BCP relaxation timescales, this process created vertical l-BCP nanodomains with controlled feature sizes via molecular weight control. Besides regulating the out-of-plane nanostructure orientation, the alignment of BCP microdomains in-plane was locally tuned by biasing the BCP assembly energetics using an edge-templating strategy. The relaxation of residual stresses and minimization of chain distortion energy penalties along the film boundary were the factors governing the edge-templating mechanism that spontaneously aligns the BCP microdomains orthogonal to the film-discontinuity. Both, kinetic and thermodynamic factors were associated with the boundary-propagation effect. This research demonstrates a new paradigm for advancement of BCP nanotemplating and nanolithography applications due to its potential to fabricate user-defined hierarchical micro-nanopatterns.
Block Copolymer Self Assembly
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Author : Gayashani Kanchana Ginige
language : en
Publisher:
Release Date : 2022
Block Copolymer Self Assembly written by Gayashani Kanchana Ginige and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with Block copolymers categories.
Molecular self-assembly is the basis of structure in nature. While of far less complexity than a natural system, the same physical rules apply to simple synthetic designed systems that spontaneously form self-assembled structures and patterns. The self-assembly of block copolymers (BCPs) is an interesting example, as it can be harnessed to form both 2D (in thin films) and 3D (in bulk) porous and chemically controlled morphologies at scale. The self-assembly of BCPs on surfaces is of interest for a range of applications, but due to the enormous economic driver that is the computer industry, this direction has been pushed most strongly. Self-assembly of BCPs has been described in the International Technology Roadmap for Semiconductors (the ITRS, and now the IDRS) for almost two decades for lithography on semiconductors and for patterning the magnetic material of hard drives. As a result, there has been much academic interest, both fundamental and applied, to meet the challenges as outlined in the ITRS/IDRS due to the promise of this scalable and low-cost nanopatterning approach. More recently, the remarkable work harnessing BCP self-assembly has been directed to other applications, one being optical metamaterials; this thesis will add to this growing body of science. One aspect holding BCP self-assembly back is the defectivity in the patterned material or surface; some applications are more defect tolerant than others, but hard drive and other computer-industry applications have very low tolerance for defects. It is, therefore, important to have systematic control over the self-assembly process as well as quality of the final patterns generated by BCP self-assembly for these applications and others not yet imagined. This thesis examines the defectivity of the hexagonal nanoscale patterns derived from BCP self-assembly and looks at extending them to produce nanoscale patterns of native and non-native morphologies that have plasmonic properties. This thesis is divided into two parts. The first part deals with optimization of solvent vapor annealing of BCP self-assembly, the critical step in which the actual nanoscale phase segregation takes place; in this case, it uses a controlled solvent vapor flow annealing apparatus, design of experiment and machine learning approaches. In this work, it was discovered that slight variations in the initial film thickness on the order of even a couple of nanometers and the final swelling degree have a huge influence on the defectivity and the quality of the resulting patterns. Next, machine learning approaches are applied to compile qualitative and quantitative defect analysis into a single figure of merit that is mapped across an experimental parameter space. This approach enables faster convergence of results to arrive at the optimum annealing conditions for the annealing of thin films of BCPs of PS-b-PDMS that generate nanoscale hexagonal patterns of silica dots with a minimum number of defects. In the second part of the thesis, mixed metal/oxide double layer patterning was studied using sequential self-assembly of BCPs. The second part of the thesis starts with optimization of reactive ion etching (RIE) for producing single layer metal nanopatterns from metal ion-loaded thin films of PS-b-P2VP BCPs to generate single layers of hexagonal metal nanopatterns that can withstand a second consecutive reactive ion etching step. The goal of this work is to enable density doubled and/or Moiré pattern formation via self-assembly of a second layer of BCP on the initial pattern prepared by self assembly of either the same or different BCP, as will be described in Chapter 4. Therefore, the initial pattern produced via BCP self-assembly and RIE etching would need to withstand a second treatment step of BCP self-assembly and RIE. While single layer nanopatterns of Au and Pt nanoparticles can be produced without much trouble, these resulting patterns could not be applied for density multiplication of metal-metal nanopatterns since the metal dots become too small and disordered. To demonstrate that metal nanoparticles derived from BCPs could be used, at least, to produce a mixed metal oxide/metal patterns, arrays of SiOx dots were first produced from PS-b-PDMS BCPs and then layered a BCP of PS-b-P2VP that was subsequently loaded with gold or platinum ions. Upon RIE etching, the BCP is removed and the SiOx/Au or Pt nanoparticle arrays were produced. Based upon the outcomes of the optimization of the etching work, mixed Au-Pt commensurate and incommensurate hexagonal lattice patterns were produced on both silicon and quartz substrates. Finally, the optical properties of these mixed metal Pt-Au bilayer patterns were studied. They demonstrated interesting plasmonic properties of the bilayer patterns, including consistent observation of extended plasmon bands that suggest coupling of the localized surface plasmon resonances (LSPRs) of the gold nanoparticles through proximal platinum nanoparticles when arrayed in periodic patterns.
Directed Self Assembly Of Block Copolymer Films On Chemically Nanopatterned Surfaces
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Author : Adam M. Welander
language : en
Publisher:
Release Date : 2009
Directed Self Assembly Of Block Copolymer Films On Chemically Nanopatterned Surfaces written by Adam M. Welander and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Directed Self Assembly Of Block Copolymers With Functional Materials
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Author : Yi Ding (Ph.D.)
language : en
Publisher:
Release Date : 2017
Directed Self Assembly Of Block Copolymers With Functional Materials written by Yi Ding (Ph.D.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
Block copolymers (BCPs) are a class of soft materials consisting of two (or more) different chains joint together by covalent bond. This special chemical structure leads to microphase separation and consequently a variety of highly controllable self-assembly patterns. Directed self-assembly (DSA) of BCPs has therefore emerged as one of the most promising technologies to fabricate functional nanostructures and is able to produce patterns with ultra-small resolution (sub-10 nm) while maintaining high throughput and order. However, existing DSA methods depend mostly on carbon or silicon-based BCPs, thus lack functionality for sophisticated applications. This work aims at expanding the capability of DSA techniques by exploring new ways of incorporating functional materials into the BCP matrix and by imposing non-native symmetries on the BCP patterns. First, we focused on constructing nanocomposite thin films composed of BCPs and various types of functional materials (i.e., inorganic ions, inorganic-organic complex, organic compounds and nanoparticles). Based upon this methodology, we developed novel ways of fabricating mesoporous thin film structures with rectangular, triangular and quasicrystalline symmetries by means of graphoepitaxial post array templates. On the other hand, we also examined the limits of DSA by introducing artificial noise to mimic fabrication errors and studied the corresponding responses from BCP. This study demonstrates the potential of DSA of BCP in building thin film nanostructure of unconventional symmetries with functional components.
Templated Self Assembly Of Novel Block Copolymers
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Author : Li-Chen Cheng (Ph.D.)
language : en
Publisher:
Release Date : 2019
Templated Self Assembly Of Novel Block Copolymers written by Li-Chen Cheng (Ph.D.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
Self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous technological applications to fabricate a variety of nanoscopic structures. The resulting feature sizes range from a few to several hundred nanometers, and are readily tunable by varying the molecular weights of block copolymers. Directed self-assembly of block copolymer is an effective way to pattern periodic arrays of features with long-range order, to generate complex patterns, and to multiplicatively increase the pattern density and resolution that are far beyond the limit of conventional lithography. Despite of the significant progress in the area of directed self-assembly in recent years, critical research problems regarding the dimension scalability toward sub-10-nm regime and large feature sizes on hundreds of nanometers scale as well as the capability of generating complex device-oriented patterns remain challenging. In this thesis, BCP systems, including high-v BCPs that are capable of self-assembling into extreme small and large feature sizes as well as those with more complex block architectures, are identified and studied in order to understand how those materials may be processed and directed selfassembly to bridge the patterning size spectrum between nano- and micro-fabrication. Another focus is placed on the scientific exploration of directed self-assembly of triblock terpolymers and the investigation on the mechanisms that regulate the scaling and geometry of self-assembled patterns. A comprehensive understanding about self-assembly of BCP thin films will enable developing device-oriented geometries, manipulating BCPs phase behavior, and incorporating new functional materials for a wider range of applications. In the meanwhile, optimizing the processing condition of self-assembly of various BCPs is essential to confirm viability of the directed self-assembly of block copolymers process in manufacturing.
Directed Self Assembly Of Block Copolymer Thin Films By Electrospray Deposition
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Author : Hanqiong Hu
language : en
Publisher:
Release Date : 2015
Directed Self Assembly Of Block Copolymer Thin Films By Electrospray Deposition written by Hanqiong Hu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Block Copolymer Self Assembly A Computational Approach Towards Novel Morphologies
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Author : Karim Raafat Gadelrab
language : en
Publisher:
Release Date : 2019
Block Copolymer Self Assembly A Computational Approach Towards Novel Morphologies written by Karim Raafat Gadelrab and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
Spontaneous self-assembly of materials is a phenomenon exhibited by different molecular systems. Among many, Block copolymers (BCPs) proved to be particularly interesting due to their ability to microphase separate into periodic domains. Nonetheless, the rising need for arbitrary, complex, 3D nanoscale morphology shows that what is commonly achievable is quite limited. Expanding the range of BCPs morphologies could be attained through the implementation of a host of strategies that could be used concurrently. Using directed self-assembly (DSA), a sphere forming BCP was assembled in a randomly displaced post template to study system resilience towards defect creation. Template shear-like distortion seemed to govern local defect generation. Defect clusters with symmetries compatible with that of the BCP showed enhanced stability. Using 44 and 32434 Archimedean tiling templates that are incompatible with BCP six-fold symmetry created low symmetry patterns with an emergent behavior dependent on pattern size and shape. A variation of DSA is studied using modulated substrates. Layer-by-layer deposition of cylinder forming BCPs was investigated. Self-consistent field theory (SCFT) and strong segregation theory SST were employed to provide the understanding and the conditions under which particular orientations of consecutive layers were produced. Furthermore, deep functionalized trenches were employed to create vertically standing high-[chi] BCP structures. Changing annealing conditions for a self-assembled lamellar structure evolved the assembled pattern to a tubular morphology that is non-native to diblock copolymers. A rather fundamental but challenging strategy to go beyond the standard motifs common to BCPs is to synthesize multiblock molecules with an expanded design space. Triblock copolymers produced bilayer perforated lamellar morphology. SCFT analysis showed a large window of stability of such structures in thin films. In addition, a model for bottlebrush BCPs (BBCPs) was constructed to investigate the characteristics of BBCPs self-assembly. Pre-stacked diblock sidechains showed improved microphase separation while providing domain spacing relevant to lithography applications. A rich phase diagram was constructed at different block concentrations. The ability to explore new strategies to discover potential equilibrium morphologies in BCPs is supported by strong numerical modeling and simulations efforts. Accelerating SCFT performance would greatly benefit BCP phase discovery. Preliminary work discussed the first attempt to Neural Network (NN) assisted SCFT. The use of NN was able to cut on the required calculations steps to reach equilibrium morphology, demonstrating accelerated calculation, and escaping trapped states, with no effect on final structure.
Dynamic Temperature Gradient Directed Self Assembly Of Block Copolymer Nanoparticle Thin Films
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Author : Ren Zhang (Chemical engineer)
language : en
Publisher:
Release Date : 2013
Dynamic Temperature Gradient Directed Self Assembly Of Block Copolymer Nanoparticle Thin Films written by Ren Zhang (Chemical engineer) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Block copolymers categories.
Block copolymers (BCPs) have received considerable attention as a promising platform for synthesis of heterogeneous nanomaterials and fabrication of nanostructures with improved electrical, optical, or mechanical properties. Here we demonstrate a facile fabrication strategy towards long-range ordered block copolymer/nanoparticle (BCP/NP) hybrid structures utilizing a novel dynamic thermal field-induced gradient soft-shear process (CZA-SS). Structural uniformity of nanocomposite films is quantified in terms of the orientation order parameter (S) and it is demonstrated that CZA-SS can facilitate unidirectional alignment with low loading fraction of AuNP additives. The application of sharp dynamic thermal gradient process (CZA-S) is shown to result in the morphological transition from out-of plane to in-plane cylinder orientation that is rationalized as a consequence of suppressed normal expansion of AuNP filled BCP films. Our current work may open new avenues for fabrication of unidirectional oriented hybrid materials,
The Self Assembly Of Lamellae Forming Block Copolymer For High Resolution Nanolithography
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Author : Zhiwei Sun
language : en
Publisher:
Release Date : 2017
The Self Assembly Of Lamellae Forming Block Copolymer For High Resolution Nanolithography written by Zhiwei Sun and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
This thesis will be focused on the thin film self-assembly and high resolution nanolithography of lamellae-forming PS-b-P2VP block copolymer. Some of the scientific and engineering problems of block copolymer self-assembly will be studied using the state-of-the-art characterization facilities including AFM, SEM and synchrotron radiation X-ray scattering, pushing forward the application of block copolymer in high resolution nanolithography, storage media, and separation membranes, etc. The first challenge is the design of BCP with small domain spacing, which defines the resolution of BCP nanolithography. Small domain spacing can be achieved by reducing the degree of polymerization, but order-to-disorder transition happens when the critical [chi]N is reached. In this thesis, we will first discuss the disorder-to-order transition of low molecular weight PS-b-P2VP by increasing the [chi] parameter using salt doping. The domain spacing of PS-b-P2VP will be pushed down one step further by design BCPs with star shape chain architecture, achieving lamellar nanostructures with sub-10 nm repeating period. Another challenge that hampers the application of BCP is the defect in the self-assembled BCP thin film. The defects in the thin film reduces the grain sizes of BCP lattices and also brings in new challenges in lithography and pattern transfer, thus the defect density in the self-assembled BCP thin film has to be reduced. It is important to understand how the defects were generated and how it can be removed using annealing and directed self-assembly (DSA). In this thesis, in situ grazing incidence small angle X-ray scattering will be used to characterize the solvent vapor annealing of P2VP-b-PS-b-P2VP triblock copolymer in thin film. The trade-off between the in-plane and out-of-plane defect density was revealed during solvent evaporation. Furthermore, long-range ordered lamellar line patterns were prepared using directed self-assembly on patterned substrate.