Bulletin of the American Physical Society
2008 APS March Meeting
Volume 53, Number 2
Monday–Friday, March 10–14, 2008; New Orleans, Louisiana
Session A25: Block Copolymer Thin Films |
Hide Abstracts |
Sponsoring Units: DPOLY Chair: Alamgir Karim, National Institute of Standards and Technology Room: Morial Convention Center 217 |
Monday, March 10, 2008 8:00AM - 8:12AM |
A25.00001: Control of P(S-b-PMMA) Orientation on Organosilicate Substrates by Thermal Treatment Kookheon Char, Hyoseon Suh One of most important factors to control the orientation of microdomains in block copolymer films is the wetting behavior of a block copolymer at an interface. From this perspective, we studied the wetting behavior of P(S-b-MMA) block copolymer (BCP) thin films on silsesquioxane-based organosilicate (OS) substrates, which have potential applications as interlayer dielectrics (ILDs) for next generation semiconductor devices. We controlled the surface energy of OS substrates by changing the treatment temperature. As the treatment temperature was increased, the wetting behavior of a P(S-b-MMA) film on OS substrates changed from the asymmetric to the symmetric wetting, which allowed us to find the optimum treatment temperature for the neutral wetting behavior. Changes in the orientation of BCP microdomains on OS substrates were analyzed by AFM, FE-SEM, and GI-SAXS. These results show the potential that the OS ILDs prepared in this study do not require any additional surface modifications such as random copolymer brushes or SAMs for BCP microdomains to orient perpendicular to the substrate, which could ultimately be applied to BCP lithography. [Preview Abstract] |
Monday, March 10, 2008 8:12AM - 8:24AM |
A25.00002: Functionalization of PEO Nanocylinder Array Structure in Block Copolymer Thin Film. Kaori Kamata, Tomokazu Iyoda Phase-separated nanostructure of block copolymer has been intensively studied as one of the most promising candidates for many important nanotechnological applications, because the feature size of domain structure generated by block copolymers is ranging to a level of several nanometers. We have studied the nanostructures of block copolymers, which are based on the use of amphiphilic block copolymer, PEO-b-PMA(Az), to establish the long range orderness onto the substrate. Here, we describe the nanotemplating process with domain selective doping of PEO cylindrical domains, using various kinds of metal cation sources, such as Fe or Pb ions. Furthermore, the ionic liquid also hybridized into the PEO nanocylinders to form liquid nanochannels perpendicular to the substrate. A wide variety of cations were successfully incorporated through the coordination bonding with the oxygen in PEO chain. The resulting metal cation hybrid films could offer the metallic nanopillar arrays, with the nanostructure-specific electrochemical, electric or magnetic properties. [Preview Abstract] |
Monday, March 10, 2008 8:24AM - 8:36AM |
A25.00003: Block copolymer mask with cylindrical nanochannels for wet nanopatterning on silicon wafer Ryoko Watanabe, Kaori Kamata, Tomokazu Iyoda Microphase-separated structure of block copolymer (BC) thin film has been considered as a mass-productive nanomask, in which the periodicity of the pattern can be tuned by molecular weight. We have developed a series of amphiphilic BC, PEO$_{m}b$-PMA(Az)$_{n}$, consisting of hydrophilic, ion-conductive poly(ethylene oxide) (PEO) and hydrophobic poly(methacrylate) with azobenzene in its side chain. This BC forms hexagonally arranged PEO cylinders which span across the thickness of the film after thermal annealing. In this study, PEO cylinders were blended with poly(ethylene glycol) monomethylether to provide effective nanochannels that can perpendicularly diffuse etching species for wet etching of silicon wafer As a quick and total wet nanopatterning process, a silicon wafer covered by the BC mask was annealed at 140 degrees C for 1 h and immersed into 33 wt{\%} NH$_{4}$F aqueous solution for 3 min. AFM observation of the resulting silicon wafer surface revealed a hexagonally arranged nanohole array with 24 nm of center-to-center distance and 10 nm of diameter was fabricated. [Preview Abstract] |
Monday, March 10, 2008 8:36AM - 8:48AM |
A25.00004: Is a short fluorinated segment sufficient to induce interfacial rearrangements in diblock co-polymers? Umesh Shrestha, Dvora Perahia, Stephan Clarson The interfacial structure of thin diblock co-polymer films is a result of internal segregation between the blocks and their affinity to the interfaces. Introducing a fluorinated group affects significantly the segregation of the fluorinated block to the interface. The interfacial structure and dynamics of thin layers of a diblock co-polymer Polytrifluoro propyl methyl siloxane-polystyrene (PTEPMS-PS) with the fraction of the fluorinated block ranging from 0.03 to 0.5was studied by neutron reflectivity. The uniqueness of this diblock lies in the presence siloxane group and a fluorinated group intercalated into one of the blocks where the siloxane offers flexibility and the fluorine exhibits low interfacial energies. While the air interface is dominated by fluorinated segments for all volume fractions, layering is observed even for the shortest fluorinated segments. The rate of rearrangement upon annealing varies with the size of the fluorinated block. [Preview Abstract] |
Monday, March 10, 2008 8:48AM - 9:00AM |
A25.00005: Multi-block copolymers in thin films. Panagiotis Maniadis, Edward Kober, Turab Lookman We study the behavior of an $\{AB\}_n$ multi-block copolymer confined to a thin film, using self consistent field theory (SCFT) methods. Due to the breaking of symmetry in the direction of confinement, the propagators do not obey the usual diffusion equation. We derive the diffusion equation which correctly describes the confined polymer system and find that it differs from the original in an area which is approximately 3 times the Kuhn length of the polymer, close to the surface of the film. We use the modified diffusion equation to study the structure of the confined polymer. [Preview Abstract] |
Monday, March 10, 2008 9:00AM - 9:12AM |
A25.00006: Two-Dimensional Instabilities in Patterned Diblock Copolymer Films Joseph Parete, Andrew B. Croll, John S. Preston, Kari Dalnoki-Veress We have developed a novel surface tension-driven laser lithography technique that enables the effective generation of microstructures in polymer systems. Combining this approach with naturally occurring instabilities in symmetric diblock copolymer films allows us to produce structures far smaller then those imposed by the resolution of the laser patterning procedure. An example of this is the Plateau-Rayleigh instability, which results in the breaking up of an extended cylinder into an arrangement of smaller, evenly spaced droplets. Since our diblock system can be considered an ideal two-dimensional system, the creation of various structures using laser lithography provides an excellent probe for studying instabilities in two dimensions. Optical and atomic force microscope measurements are presented and discussed in terms of a linear stability analysis. [Preview Abstract] |
Monday, March 10, 2008 9:12AM - 9:24AM |
A25.00007: Structure and dynamics of block copolymer films by XPCS Hyunjung Kim, Heeju Lee, Young Joo Lee, Sanghoon Song, Zhang Jiang, Sunil K. Sinha, A. Ruehm We have measured the structure and the dynamics of block copolymer films in the melt using X-ray Photon Correlation Spectroscopy. Block-copolymers films used in this study have an internal structure of spherical micelles. This ought to have a strong influence on the physical properties of the thin films. The results from the surface dynamics are compared with the theory of overdamped thermal capillary waves on thin films. By changing the incident angle, the surface dynamics and the micelle dynamics were selectively measured. The obtained viscosity will be compared with the value from the mechanical measurement of the bulk material. The surface tension obtained from static grazing incidence scattering data shows that a PDMS layer segregates to the free surface of the film. [Preview Abstract] |
Monday, March 10, 2008 9:24AM - 9:36AM |
A25.00008: Sphere-Forming and Cylinder-Forming Block Copolymer Thin Films Aligned Under Double Shear Andrew Marencic, Richard Register, Paul Chaikin Studies have shown that stress transmitted through a viscous layer to a sphere- or cylinder-forming block copolymer thin film can orient the microdomains in the direction of the imposed shear. For the creation of complex patterns, reorientation of these unidirectionally oriented films is necessary. Here we demonstrate the ability of shear to realign the microdomains along a second direction, as imaged by atomic-force microscopy. The results are in qualitative agreement with our previously proposed phenomenological model; however, the stress required for realignment is larger (factor of 2.7 for sphere-formers and factor of 1.2 for cylinder-formers) than the stress required to orient a film from the polygrain state. We also observed grain boundary generation within the transition region between alignment with the first shear direction and alignment with the second shear direction. No noticeable change in the dislocation density or its angular distribution was observed in the sphere-forming block copolymer thin films following the second shear. [Preview Abstract] |
Monday, March 10, 2008 9:36AM - 9:48AM |
A25.00009: Rapid Directed Assembly of Block Copolymer Films on chemically patterned surfaces at Elevated Temperatures Adam Welander, Paul Nealey We report on the rapid directed assembly of poly(styrene-b-methyl methacrylate) (PS-b-PMMA) block copolymer thin films at elevated temperatures well above the glass transition temperature (Tg) on chemically patterned surfaces. The time needed for defect free assembly, where the chemical pattern (L$_{S})$ closely matches the natural length of the block copolymer (L$_{0})$, is strongly dependant on the annealing temperature. Annealing times range from 150 minutes at 180 \r{ }C to 3 minutes at 230 \r{ }C. This system behavior is well described as a simple thermally activated process with an apparent activation energy (\textit{$\Delta $E}$_{a})$ of 182 kJ/mol and a polymer diffusion coefficient of 7.5E-15 cm$^{2}$s$^{-1}$ at 190 \r{ }C. Modeling this behavior predicts annealing times of 13.5 seconds at 250 \r{ }C and 1.9 seconds at 280 \r{ }C. While these times are difficult to investigate experimentally, a one minute anneal at these elevated temperatures not only shows perfect assembly where L$_{S}$ = L$_{0}$, but also where L$_{S} <$ L$_{0}$. [Preview Abstract] |
Monday, March 10, 2008 9:48AM - 10:00AM |
A25.00010: Precise Control of 3-dimensional Block Copolymer Assembly using 2-dimensional Chemical Templates Sangcheol Kim, Hae-Jeong Lee, Ronald L. Jones, Alamgir Karim, R.M. Briber, Ho-Cheol Kim Chemically heterogeneous substrates, where the periodicities of the chemical pattern are close to those of lamellar microdomains of block copolymers, have been used as an effective route to align the microdomains with a low number density of defects. Macroscopic chemical heterogeneity is, however, still valuable for providing insights on ordering behavior of block copolymers. Using a series of chemical patterns with micrometers length scales, we studied the wetting and self-assembly behavior of poly(styrene-b-methyl methacrylate) (PS-b-PMMA). We found that the variation in morphology and orientation of microdomains are governed by the degree of chemical contrast and the size of the underlying chemical patterns. The two-dimensional chemical template is shown to precisely control the three dimensional assembly of the block copolymer film. [Preview Abstract] |
Monday, March 10, 2008 10:00AM - 10:12AM |
A25.00011: Novel Complex Nanostructures from Directed Assembly of Block Copolymers on Incommensurate Surface Patterns. Sang Ouk Kim, Bong Hoon Kim, Harun H. Solak, Dong Meng, Qiang Wang Self-assembled nanostructures of block copolymer thin films have attracted enormous attention as useful templates for nanofabrication. We present that a chemically nanopatterned surface prepared by photolithography is able to direct the assembly of a block copolymer thin film to form a novel complex nanostructure. When a cylindrical block copolymer was assembled on a stripe pattern, whose pattern period was twice as large as a natural lattice size of the bulk nanostructure, a new structure was produced, where cylinders were alternately oriented parallel and perpendicularly to the surface. Self-consistent field calculations supported the emergence of the new structure, providing insight into the detailed structure and formation mechanism. Our work suggests that the combining top-down and bottom-up approaches may provide a versatile pathway for fabricating well-registered complex nanostructure, potentially useful in diverse advanced applications. References; S. O. Kim, et al. Nature 424, 411 (2003); M. P. Stoykovich, et al. Science 308, 1442 (2005); S. O. Kim, et al. Macromolecules 39, 5466 (2006); S. O. Kim, et al. Advanced Materials 19, 3271 (2007). [Preview Abstract] |
Monday, March 10, 2008 10:12AM - 10:24AM |
A25.00012: Templated Self-Assembly of Asymmetric Ternary Blends of Block Copolymers and Homopolymers Karl Stuen, Francois Detcheverry, Carla Thomas, Richard Farrell, Michael Morris, Juan de Pablo, Paul Nealey Templated assembly of ternary blends of cylinder-forming PS-\textit{block}-PMMA and homopolymers of PS and PMMA was investigated experimentally and with Monte Carlo simulations of a coarse-grained model. The blends were deposited into trench features coated with a neutral brush to induce cylinder orientation perpendicular to the substrate. The ternary blends were used to systematically control the commensurability between the blend and trenches of constant width. Important patterning parameters such as the degree of perfection, the domain spacing perpendicular and parallel to the confining template, the domain uniformity, and shape of the unit cell were quantified as a function of blend composition. The cylindrical nanostructures appear to have improved uniformity across the trench width compared with spherical systems. [Preview Abstract] |
Monday, March 10, 2008 10:24AM - 10:36AM |
A25.00013: Directed Assembly of Asymmetric Ternary Block Copolymer-Homopolymer Blends Thin Films on Checkerboard Trimming Chemical Pattern Huiman Kang, Paul F. Nealey Typical 2-dimensional projections of ordered block copolymer morphologies in thin films include periodic lines or hexagonal arrays of spots and therefore may not be suitable for patterning even strictly periodic device-oriented arrays, such as checkerboard trimming patterns (alternating lines and dashed lines) used in the fabrication of dynamic random access memory (DRAM). Here we direct the assembly of asymmetric ternary polystyrene-block-poly(methylmethacrylate) (PS-b-PMMA)/homopolymer PS/homopolymer PMMA blends on checkerboard trimming chemical patterns. The degree of perfection and domain uniformity of the assembled films was quantified as a function of overall composition of PS or PMMA and total homopolymer fraction in the blends. By matching polymer volume fractions and pattern area fractions, blends composed of lamellae-forming block copolymer and substantially asymmetric fractions of the two homopolymers could be assembled into equilibrated line and dash morphologies. [Preview Abstract] |
Monday, March 10, 2008 10:36AM - 10:48AM |
A25.00014: Influence of added copolymers on thin film polymer blends studied by atomic force microscopy: surface morphology and dewetting Dean Waldow, Jenifer Hoffert, Kris Peterson Atomic force microscopy (AFM) was used to study thin film polymer blends of polystyrene (PS) and polybutadiene (PB). These blends were studied with increasing concentration of block, random, and graft copolymers. Thin films were prepared by spin coating from a good solvent, which resulted in film thicknesses of approximately 65 nm. The AFM data were collected in AC mode and included both topographic and phase data. The topography data were analyzed using lateral Fourier Transform analysis as well as real space techniques both lateral and normal to the surface. The results suggest that lateral phase separated domain size decreases with increasing copolymer concentration for each of additives studied and for all concentrations. The evolution of the phase separated morphologies and dewetting was also studied by an anneal / quench technique as well as real time monitoring at temperatures above the PS glass transition temperature. Results for the domain evolution experiments demonstrate significant suppression of lateral domain growth and some suppression of large encapsulated domains seen in the binary blend. The graft copolymer demonstrated the most significant effects with the diblock and random copolymers following in significance respectively. [Preview Abstract] |
Monday, March 10, 2008 10:48AM - 11:00AM |
A25.00015: Controlled Dimensions of Nanostructures in Asymmetric Ternary Blends of Block Copolymers and Homopolymers in Thin Films Carla Thomas, Karl Stuen, Nicola Ferrier, Paul Nealey Ternary blends of cylinder-forming PS-\textit{block}-PMMA and homopolymers of PS and PMMA were investigated in thin films on a neutral brush with the domains oriented perpendicular to the substrate. Five blends with homopolymers having different degrees of polymerization (N) were studied to quantify the dimensional scaling of the domains and suitability for patterning. In the dry brush regime, the best pattern uniformity and fewest defects were found when N of the homopolymers matched N of the corresponding block of the block copolymer. The lattice spacing of the cylindrical array, $D$, and cylinder diameter uniformity changed with $\phi _{H}$, the homopolymer volume fraction in the film, and N of the hompolymers$_{.}$ With the ternary blends, $D$ could be increased up to 200 percent relative to the neat block copolymer; the ternary blends allow $\phi _{H }$greater than 0.4 without inducing a phase change. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700