Graphoepitaxy of Spherical Domain Block Copolymer Films

Abstract

The long‐range order of spherical block copolymer films is greatly improved if the underlying surface has been etched to form wells and mesas. Epitaxial growth of polystyrene/poly(2‐vinylpyridine) block copolymers on SiO2 with structures 1–10 μm wide yields single‐crystal‐like structures on top of the mesas (see Figure), and in the wells, provided the height of the mesas exceeds one layer of copolymer spheres (27 nm). (See also inside front cover.)

A Path to Ultranarrow Patterns Using Self-Assembled Lithography

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Templated self-assembly of block copolymer thin films can generate periodic arrays of microdomains within a sparse template, or complex patterns using 1:1 templates [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . However, arbitrary pattern generation directed by sparse templates remains elusive.

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“…Block copolymer thin film self-assembly on an unpatterned substrate leads to close-packed arrays of features such as lines or dots that lack long-range order, thus limiting their utility. As a result, both chemical and topographical substrate features have been used to template or guide block copolymer self-assembly, imposing long-range order and generating microdomain geometries not observed in untemplated films [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] . These templates are often defined using electronbeam lithography (EBL) [3][4][5]7,8,11 , because of its ability to pattern small features of arbitrary geometry.…”

“…Most work on the templated self-assembly of block copolymers for nanolithography has focused on the generation of periodic patterns of parallel lines, close-packed dots or concentric rings, using shallow trenches 1,6,9,10,[12][13][14]22,24,26 , sparse post arrays 3 or chemical templates with a periodicity either similar to that of the BCP 2,7,8,15 or a factor two, three or four times larger 3-5 . Nealey and colleagues have shown that non-regular features such as lamellae with bends 2,11 or square-packed dots 15 could be formed using a chemical pattern of the same density as the desired block copolymer pattern.…”

Rectangular Symmetry Morphologies in a Topographically Templated Block Copolymer

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This method has been used to produce large-area defect-free lamellar, cylindrical, or spherical microdomain patterns through chemical [1][2][3][4][5][6] or topographical [7][8][9][10][11][12][13][14][15] templating. However, the formation of complex patterns with multiple morphologies in one BCP film (e.g.…”

Morphological Transitions of Symmetric Polystyrene-block-Poly(1,4-butadiene) Copolymers in Thin Films upon Solvent-Annealing

“…However, the window of annealing temperatures for BCPs is normally limited because of their possible thermal degradation. Recently, some remarkable methods to achieve well-defined BCP ordering in large areas have been introduced, including interfacial interaction control, 5,15 electric field, 16,17 solvent vapor treatment, 18-23 chemically patterned substrate, 24 graphoepitaxy, 25 and epitaxial growth. 26 The solvent-annealing, among several approaches introduced above, has advantages for practical reasons.…”