Surface patterns from block copolymer self-assembly
Phase diagram for diblock copolymers. Left: equilibrium morphologies predicted by self-consistent mean-field theory. Right: experimental phase diagram of poly(styrene--isoprene) diblock copolymers. (Reprinted with permission from Ref. 11.)
[(a) and (b)] Tapping mode scanning force microscopy phase images of thin polystyrene-polybutadiene-polystyrene (SBS) films on silicon substrates after annealing in chloroform vapor. (c) Schematic height profile of (a) and (b). (d) Simulation results with film thickness increasing from left to right. [Reprinted with permission from A. Knoll, A. Horvat, K. S. Lyakhova, G. Krausch, G. J. A. Sevink, A. V. Zvelindovsky, and R. Magerle, Phys. Rev. Lett. 89, 035501 (2002). Copyright 2002 by the American Physical Society.]
(a) Schematic cross-sectional profile of thin films of symmetric PS--PMMA on silicon oxide surface. (b) Height contrast AFM image of a PS--PMMA thin film which shows hole formation on the surface.
SEM micrographs of laterally segregated diblock copolymer films (scan size: ). (Reprinted with permission from Ref. 22.)
(a) Tapping mode AFM image of ultra thin PS--PHOST films formed on topographic patterns (scale bar: ). (b) Monte Carlo simulation results of micelles positioning on the mesa array. (Reprinted with permission from Ref. 23.)
(a) Morphologies shown in cross section. Black indicates 100% segments and white 100% . (b) Example phase diagram. (Reprinted with permission from Ref. 27.)
Top: synthetic scheme for end-functionalized random copolymer. Bottom: contact angle of PS (circles) and PMMA (triangles) on P(S--MMA) random copolymer brushes as a function of styrene fraction . (Reprinted with permission from Ref. 28.)
Tapping mode AFM image of an asymmetric PS--PMMA thin film on neutral substrate. Left: height contrast image. Right: phase contrast image. Bright dots in phase contrast image are cylindrical PMMA microdomains oriented perpendicular to the surface.
Left: schematic representation of high density nanowire fabrication in a polymer matrix prepared by applying an electric field. Right: SEM image of a fracture surface of an array of Co nanowires grown in nanopores formed from block copolymers. (Reprinted with permission from Ref. 33.)
Cross-sectional SEM images for mixtures of PS--PMMA/PMMA with PMMA fraction of 0.26. (a) thick, (b) thick film. PMMA phases were removed using UV. (Reprinted with permission from Ref. 34.)
Schematic representation of PS--PMMA morphology of as-cast film and subsequently annealed under different solvent vapor. (a) As-cast film, (b) exposed to tetrahydrofuran (THF), (c) exposed to , and [(d)–(f)] exposed to acetone with increasing exposure time. (Reprinted with permission from Ref. 37.)
Plan-view bright-field TEM images of the as-cast SBS thin films. Films are stained with . Insets: Fourier transforms. (a) Fast, (b) intermediate, (c) slow, and (d) very slow evaporations. (Reprinted with permission from Ref. 36.)
Schematic representation (left) and cross-sectional SEM image (right) of high aspect ratio nanoporous template prepared by transferring the block copolymer patterns into underlying polymer layer using plasma etching. (Reprinted with permission from Ref. 41.)
Tapping mode AFM images of crystallized block copolymer thin films. [(a) and (b)] Taken from an area in the middle of the sample. [(c) and (d)] Taken close to a three-phase contact line created by a dewetting process which occurred in the molten state. [Reprinted with permission from G. Reiner, G. Castelein, P. Hoerner, G. Riess, A. Blumen, and J.-U. Sommer, Phys. Rev. Lett. 83, 3844 (1999). Copyright 1999 by the American Physical Society.)
(a) AFM image acquired on a copolymer sample aligned by PDMS pad. The arrow indicates the shearing direction. (b) AFM image acquired away from (a). (c) AFM image of sample without shearing. (d) Cartoon of a single layer cylindrical microdomains. Scale . (Reprinted with permission from Ref. 43.)
(a) A PS--PEO thin film obtained by spin coating, (b) after annealing for in a benzene vapor, (c) triangulational image of the AFM image in (b), and (d) the number of five-neighbor defects as a function of annealing time. (Reprinted with permission from Ref. 39.)
Top: AFM phase images of PS--PMMA thin films annealed with push velocities of (a) , (b) , (c) , and (d) . Bottom: false color cylinder orientation maps. (Reprinted with permission from Ref. 47.)
Scanning force microscopy of poly(styrene-b-2-vinylpyridine) (PS-P2VP) film on top of a mesa. Top left: fast Fourier transform of the image. Top right: schematic representation of the block copolymer thin films. (Reprinted with permission from Ref. 48.)
Lamellar microdomains of PS--PMMA on topographically patterened substrates. (a) Gold (PS selective) sidewalls and neutral bottom, (b) SiO2 substrate, and (c) neutral sidewalls and bottom. (Reprinted with permission from Ref. 54.)
SEM image of the lamellae on a substrate containing corrugated patterns. (a) A low magnification SEM image. Randomly aligned lamellae are observed on the flat surface (outside of the dotted square). The lamellae on the corrugated area (within the dotted square) show alignment perpendicular to the direction of substrate corrugation (vertical lines in the image, , ). (b) A high magnification SEM image of aligned lamellae. The horizontal and vertical lines are lamellae and substrate corrugation from e-beam lithography, respectively. (c) A tilted SEM image. (d) A high magnification SEM of Fig. 3(c). The lamellae (horizontal lines) run over the substrate corrugation (vertical lines) and form wavelike structure on the corrugated substrate. (Reprinted with permission from Ref. 56.)
AFM tapping mode phase images of PS--PMMA files of a range of molecular weights deposited on strip period. (a) Degree of commensurability , (b) , (c) , (d) , (e) , (f) , and (g) . The scale bar in (e) is . The inset is the calculated two-dimensional orientation function of each sample. [Reprinted with permission from L. Rockford, Y. Liu, P. Mansky, T. P. Russell, M. Yoon, and S. G. J. Mochrie, Phys. Rev. Lett. 82, 2602 (1999). Copyright 1999 by the American Physical Society.]
Top: schematic representation of DSA using chemical guiding patterns. Bottom: lamellar microdomains of PS--PMMA on (a) unpatterned and (b) patterned surfaces. (Reprinted with permission from Ref. 58.)
Resist requirements for future semiconductor manufacture (values from Ref. 1).
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