Download or read book Control of C60 POSS Nanoparticle Locaiton in Directed Self assembly of Block Copolymer Thin Films written by Jiajie Qian and published by . This book was released on 2014 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the advantage in self-assembly property of block copolymer (BCP), the nanoscale periodic patterns produced by the block copolymer have recently been identified as the next-generation precursor technique in many fields like nanolithographic templates, magnetic data storage, nanoporous membranes. The range of BCP periodicity is usually between 5nm and 100nm. By changing the molecular weight (N), volume fraction (f) of the components and segmental interaction, the anticipated results vary. These variations include BCP with lamellar, cylindrical, gyroid and spherical structures. Cylinder and lamella BCP are the invested especially popular, as their strong preferential interaction on the substrate results in the parallel or vertical orientation of micro domain. On the other hand, the material properties such as conductivity, hydrophilicity, mechanical and optical properties will be significantly affected depending on the way how nanoparticles (NPs) disperse within the polymer matrix. Therefore the ability to control the NPs arrangement is required. Although, a variety of methods have been explored to guide the NPs into the expected location, the ability to control positioning is still very limited, especially when the novel NPs are applied. The kinetics and intermolecular attraction are the generally accepted methods used to estimate the NPs location. In this study, location and dispersion of dumbbell-shaped fullerene (C60) bonding polyhedral oligomeric silsesquioxane (POSS) NPs were investigated on a variety of polystyrene (PS) and polymethylmethacrylate (PMMA) derivative polymer conditions. In the cases of homopolymers and polymer blends samples, the priority of C60-POSS NPs to PMMA phase was achieved due to the intermolecular forces. For the Z-direction distribution, enrichment areas of C60-POSS NPs were detected both on the top layer and bottom layer after the thin film samples were annealed due to the lower surface energy of C60-POSS NPs. Additionally, the exotic C60-POSS NPs would affect the PS-PMMA block copolymer self-assembly results involving both surface morphology and inner structure. More horizontal cylinders would form as the proportion of C60-POSS NPs was increased. In this study, Cold Zone Annealing-sharp was also used as a novel thermal annealing approach to explore the potential influences on the alignment of BCP/NPs nanocomposite.

Download or read book Directed Self assembly of Block Co polymers for Nano manufacturing written by Roel Gronheid and published by Woodhead Publishing. This book was released on 2015-07-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The directed self-assembly (DSA) method of patterning for microelectronics uses polymer phase-separation to generate features of less than 20nm, with the positions of self-assembling materials externally guided into the desired pattern. Directed self-assembly of Block Co-polymers for Nano-manufacturing reviews the design, production, applications and future developments needed to facilitate the widescale adoption of this promising technology. Beginning with a solid overview of the physics and chemistry of block copolymer (BCP) materials, Part 1 covers the synthesis of new materials and new processing methods for DSA. Part 2 then goes on to outline the key modelling and characterization principles of DSA, reviewing templates and patterning using topographical and chemically modified surfaces, line edge roughness and dimensional control, x-ray scattering for characterization, and nanoscale driven assembly. Finally, Part 3 discusses application areas and related issues for DSA in nano-manufacturing, including for basic logic circuit design, the inverse DSA problem, design decomposition and the modelling and analysis of large scale, template self-assembly manufacturing techniques. - Authoritative outlining of theoretical principles and modeling techniques to give a thorough introdution to the topic - Discusses a broad range of practical applications for directed self-assembly in nano-manufacturing - Highlights the importance of this technology to both the present and future of nano-manufacturing by exploring its potential use in a range of fields

Download or read book Block Copolymer Self assembly written by Gayashani Kanchana Ginige and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Dynamic Temperature Gradient Directed Self assembly of Block Copolymer nanoparticle Thin Films written by Ren Zhang (Chemical engineer) and published by . This book was released on 2013 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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,

Download or read book Directed Self assembly of Diblock Copolymer Thin Films on Chemically Nanopatterned Substrates written by Erik WiIliam Edwards and published by . This book was released on 2005 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Directed Self Assembly of Nanostructured Block Copolymer Thin Films Via Dynamic Thermal Annealing written by Monali N. Basutkar and published by . This book was released on 2018 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Self assembly of Block Copolymers for the Fabrication of Functional Nanomaterials written by Li Yao and published by . This book was released on 2014 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the use of block copolymers which can self-assemble into different morphologies as templates to fabricate nanostructured materials. The first section (Chapters 2-4) reports the formation of mesoporous silica films with spherical, cylindrical and bicontinuous pores up to 40 nm in diameter through replicating the morphologies of the solid block copolymer (BCP) templates, polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA), via phase selective condensation of tetraethylorthosilicate in supercritical CO2. Next, directed self-assembly was used to control the orientation of cylindrical domains in PS-b-PtBA templates. Large-area aligned mesochannels in silica films with diameters tunable between 5 and 30 nm were achieved through the replication of oriented templates via scCO2 infusion. The long-range alignment of mesochannels was confirmed through GISAXS with sample stage azimuthal rotation. In the second section (Chapters 5-6), enantiopure tartaric acid was used as an additive to dramatically improve ordering in poly(ethylene oxide-block-tert-butyl acrylate) (PEO-b-PtBA) copolymers. Transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray scattering were used to study the phase behavior and morphologies within both bulk and thin films. With the addition of a photo acid generator, photo-induced disorder in the PEO-b-PtBA/tartaric acid composite system was achieved upon UV exposure which deprotected the PtBA block to yield poly(acrylic acid) (PAA), which is phase-miscible with PEO. Area-selective UV exposure using a photo-mask was applied with the assistance of trace amounts of base quencher to achieve high-resolution hierarchical patterns. Helical superstructures were observed by TEM in this BCP/chiral additive system with 3D handedness confirmed by TEM tomography. In the last section (Chapter 7), ultra-high loadings of nanoparticles into target domains of block copolymer composites were achieved by blending the block copolymer hosts with small molecule additives that exhibit strong interactions with one of the polymer chain segments and with the nanoparticle ligands via hydrogen bonding. The addition of 40 wt% D-tartaric acid to poly(ethylene oxide-block-tert-butyl acrylate) (PEO-b-PtBA) enabled the loading of up to 150 wt% of 4-hydroxythiophenol functionalized Au nanoparticles relative to the mass of the target hydrophilic domain. This was equivalent to over 40% Au by mass of the resulting well ordered composite as measured by thermal gravimetric analysis.

Download or read book Directed Self assembly of Block Copolymer Thin Films From Fundamentals Science to Applications written by and published by . This book was released on 2014 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Directed Self assembly of Block Copolymer Films on Chemically Nanopatterned Surfaces written by Adam M. Welander and published by . This book was released on 2009 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Self assembly of Block Copolymers for Nanopatterning written by Nathanael Lap-Yan Wu and published by . This book was released on 2014 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impressive developments in the semiconductor industry over the past five decades have largely been dependent on the ability to continually reduce the dimensions of devices on a chip. However, as critical dimension requirements for these devices approach the limits of photolithography, new fabrication strategies must be introduced for these remarkable advances to continue. One technology listed by the International Technology Roadmap for Semiconductors as a candidate for next-generation nanostructure fabrication is the directed self-assembly of block copolymers. Block copolymers have received significant attention of late for their ability to template large regular arrays of nanostructures with dimensions ranging from 10 to 50 nm. The production of denser sub-10 nm nanostructures is also possible by reducing the size of these polymers, but a reduction of the polymer size also compromises the quality of nanostructures, making small polymers extremely difficult to use. In this thesis, two different patterning approaches are introduced to push the nanostructure density limits possible for a given polymer. In the first, a novel patterning approach involving thin films of bilayer block copolymer domains is used to effectively double the nanostructure density patterned by a given polymer. The technique is successfully applied to different types and sizes of polymer, and can also form highly controlled arrays of patterns with the help of surface topography. By varying different process parameters during the self-assembly or subsequent plasma steps, the dimensions of these density-doubled patterns may be finely-tuned to the desired width and pitch. The surface coverage of these density-doubled nanostructures is also maximized through adjusting the film thickness and parameters in the self-assembly process. Besides using bilayer films, dense arrays of nanostructures may also be patterned using a multi-step patterning approach. In this approach, multiple layers of block copolymer films are subsequently deposited onto the substrate to template nanostructures. Because nanostructures from previous layers contribute to the surface topography, they influence the self-assembly of successive layers and more dense and complex patterns may be produced as a result.

Download or read book Directed Assembly of Block Copolymers Using Chemically and Topographically Patterned Substrates to Control and Direct the Order of Various Nanodomains written by Sang-Min Park, 1974- and published by . This book was released on 2007 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Directed Self assembly in Block Polymer Thin Films written by Cameron K. Shelton and published by . This book was released on 2017 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block polymers (BPs) have attracted significant attention for emerging nanotechnologies such as nanolithographic masks, nanotemplates, nanoporous membranes, organic photovolatics, and lithium ion battery membranes due to their ability to self-assembly into periodic assemblies of nanoscale features. Many of these applications require thin film geometries, which have additional confinement interactions in comparison to bulk self-assembly that must be understood to control nanostructure orientation, ordering, and alignment precisely. Two approaches to study the nuanced effects of these additional interactions are in situ characterization and neutron scattering, used concurrently or independently. With these techniques, more predictive and optimized methods to direct self-assembly can be established to unlock the full potential of BP thin films in commercial and research applications. In this dissertation work, four aspects of BP thin film self-assembly were explored with these powerful characterization tools. First, chlorosilane-modified substrate surfaces were employed to investigate the effect of the substrate-polymer interaction on nanostructure orientation and ordering. Predictive formalisms were developed that defined substrate wetting behavior, nanostructure ordering, and through-film orientation control as a function of total and decoupled (dispersive and polar) substrate-polymer interfacial energy components. Second, solvent vapor annealing was studied with in situ small-angle neutron scattering (SANS), neutron reflectometry (NR), and selective deuteration to determine how factors such as solvent-polymer interactions and solvent concentration affected BP thin film self-assembly. Next, in situ SANS during solvent vapor annealing with soft shear (SVA-SS) was used to track shear-induced nanostructure disordering and ordering. By understanding the kinetic pathways during SVA-SS, more robust and high-throughput methods to define the alignment direction(s) were developed. Lastly, lithium salt-doped poly(styrene-b-oligo[oxyethylene] methacrylate) films were investigated with NR to achieve the first high-resolution, non-destructive, and quantitative analysis regarding how lithium salts distribute within the conducting domain of BP electrolyte thin films. Overall, the work in this dissertation contributes predictive and translatable approaches to direct self-assembly and the design of powerful characterization strategies to extract key information from BP thin film systems to improve their rational design and application.

Download or read book Nanoparticle block Copolymer Self assembly written by Scott Charles Warren and published by . This book was released on 2007 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Brush Coated Nanoparticle Polymer Thin Films written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Executive Summary Our work was devoted to understanding the structure and properties of a class of thin film polymer nanocomposites (PNCs). PNCs are composed of polymer hosts into which nanoparticles (metallic nanoparticles, quantum dots, nanorods, C60, nanotubes) are incorporated. PNCs exhibit a diverse range of functional properties (optical, electronic, mechanical, biomedical, structural), determined in part by the chemical composition of the polymer host and the type of nanoparticle. The properties PNCs rely not only on specific functional, size-dependent, behavior of the nanoparticles, but also on the dispersion, and organizational order in some cases, inter-nanoparticle separation distances, and on relative interactions between the nanoparticles and the host. Therefore the scientific challenges associated with understanding the interrelations between the structure and function/properties of PNCs are far more complex than may be understood based only on the knowledge of the compositions of the constituents. The challenges of understanding the structure-function behavior of PNCs are further compounded by the fact that control of the dispersion of the nanoparticles within the polymer hosts is difficult; one must learn how to disperse inorganic particles within an organic host. The goal of this proposal was to develop an understanding of the connection between the structure and the thermal (glass transition), mechanical and optical properties of a specific class of PNCs. Specifically PNCs composed of polymer chain grafted gold nanoparticles within polymer hosts. A major objective was to understand how to develop basic principles that enable the fabrication of functional materials possessing optimized morphologies and combinations of materials properties. Accomplishments: We developed: (1) fundamental principles that enabled the creation of thin film PNCs possessing more complex morphologies of homopolymers and block copolymer micellar systems [1-6]; (2) a new understanding of physical phenomena associated with the structure of PNC systems and the glass transition and dynamics [7-11], including surface dynamics [12, 13]; designed PNCs to understand the connection between structure and specific optical responses of the material [14, 15]; electrorheological phenomena [16-18]; coarsening/aggregation phenomena [19, 20]; directed assembly [21] and elastic mechanical properties of thin supported films [22]. We established procedures to design and control the spatial distribution of gold nanoparticles (Au-NP), onto which polystyrene (PS) chains were end-grafted, within thin film PS hosts.[1-3] We explained how enthalpic and entropic interactions between the grafted layers and the polymer host chains, the nanoparticle (NP) sizes and shapes determine the spatial distribution of NPs within the host (i.e.: the morphology). In brief, the chemistries of the grafted chains and the polymer hosts, the degrees of polymerization of grafted and host chains (N and P, respectively), and the surface grafting densities [Sigma] influence the thermodynamic interactions. Thin films are unique: the external interfaces (substrate and free surface) profoundly influence the spatial distribution of NPs within the PNC. For example, thin films are thermodynamically less stable than their bulk analogs due to the preferential attraction between the brush-coated nanoparticles and the external interfaces (i.e.: the free surface/polymer interface and the polymer/substrate interface). We investigated the organization of the brush-coated nanoparticles within a host composed on block copolymer micelles in a homopolymer [4, 5]. Block copolymers, composed of a polymer of type A that is bonded covalently to another polymer of type B (A-b-B) are known to form micelles within homopolymers A or B.A micelle is composed of an inner core of the A component of the copolymer and an outer corona of the B-component, that resides within homopolymer B, which serves as the host. If t ...

Download or read book Directed Self assembly of Block Copolymer Thin Films by Electrospray Deposition written by Hanqiong Hu and published by . This book was released on 2015 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Solvent Vapor Assisted Self Assembly of Patternable Block Copolymers written by Joan K. Bosworth and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymer self assembly presents a method for patterning and templating applications on the 10-50 nm length scale, a smaller scale than can be easily achieved by photolithography. Here we investigate the use of functionalized polar-nonpolar block copolymers both as photopatternable self-assembling materials and for selective infiltration of one block for patterning. Block copolymer thin films with defect-free self-assembled morphology over large domains combined with careful control of the orientation of the morphology are critical for these patterning applications. Self assembly of block copolymers is facilitated by polymer chain mobility, commonly achieved by heating block copolymer films above the glass transition temperature of the blocks. However, many block copolymer systems, including those discussed here, are thermally incompatible. Swelling in a solvent vapor, called solvent annealing, provides sufficient mobility for self assembly. Solvent annealing proved critical to forming ordered structures of functional polar-nonpolar block copolymer thin films. Thermal instability initially led to limited self assembly of combined topdown/bottom-up block copolymer systems. In this case, photolithographic functionality has been designed into block copolymers, allowing the majority component of a block copolymer to behave as a negative-tone photoresist. Solvent vapor annealing has provided a simple and inexpensive method for allowing the bottom-up self assembly of these top-down photopatternable materials. An additional benefit of solvent annealing is the ability to reversibly tune the morphology formed using the selectivity of different swelling solvents to the two blocks: that is, the choice of solvent for annealing directs the formation of different morphologies in the dried film, here spherical and cylindrical. This behavior is reversible, alternating annealing sessions lead to switching of the morphology in the film. Secondary ordering techniques applied in tandem with solvent annealing can be used to further control the self assembly and give highly ordered block copolymer domains. Here we demonstrate the use of graphoepitaxy to align block copolymer self assembly to patterns in substrates. The combination of block copolymer self assembly with lithographic crosslinking in films was initially pursued to allow precise location of assembled patterns. Taking this behavior a step further, we combine solvent annealing, used to reversibly tune the self-assembled morphology, and lithographic patterning, used to prevent switching in exposed regions. This combined process has provided a method for selectively patterning 100 nm-wide domains of spherical morphology within regions of parallel-oriented cylindrical morphology. We also investigate solvent annealing of a block copolymer blended with a hydrogen bonding material that selectively segregates into the polar block. Blending provides a method of tuning the periodicity upon solvent annealing for self assembly, with morphology control again possible by solvent selectivity. Selective extraction of the blended material forms voids displaying the tunable periodicity, and the pattern is then transferred by templating to inorganic materials.

Download or read book Dynamic Thermal Field induced Directed Self assembly of Block Copolymer Thin Films written by Gurpreet Singh and published by . This book was released on 2013 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: