Dense Self‐Assembly on Sparse Chemical Patterns: Rectifying and Multiplying Lithographic Patterns Using Block Copolymers

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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“…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. However, the serial nature of EBL makes it clearly advantageous to minimize the density of the EBL-written features required to template a given arrangement of block copolymer microdomains.…”

“…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][4][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.…”

“…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. Meanwhile, Cheng and colleagues have used discontinuous chemical lines to direct the locations of lamellae 4 . In contrast, the work described here uses sparse arrays of posts to both control the in-plane orientation of linear features, according to the commensurability between the post lattice and block copolymer period, and also to create specific non-regular features by locally modifying the post shape and spacing into an arrangement that changes the preferred commensuration condition, resulting in a linear connected pattern that can be routed selectively to form complex bent structures and junctions.…”

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.…”