Directed Assembly of Block Copolymer Blends into Nonregular Device-Oriented Structures

Abstract

Self-assembly is an effective strategy for the creation of periodic structures at the nanoscale. However, because microelectronic devices use free-form design principles, the insertion point of self-assembling materials into existing nanomanufacturing processes is unclear. We directed ternary blends of diblock copolymers and homopolymers that naturally form periodic arrays to assemble into nonregular device-oriented structures on chemically nanopatterned substrates. Redistribution of homopolymer facilitates the defect-free assembly in locations where the domain dimensions deviate substantially from those formed in the bulk. The ability to pattern nonregular structures using self-assembling materials creates new opportunities for nanoscale manufacturing.

Orientation-Controlled Self-Assembled Nanolithography Using a Polystyrene−Polydimethylsiloxane Block Copolymer

“…For example, lamellar poly(styrene-bpolymethyl methacrylate) (PS-PMMA) patterns have been templated using a self-assembled monolayer patterned by extreme ultraviolet interference lithography (EUV-IL) or electron-beam (e-beam) lithography and have attracted much attention due to their high aspect ratio and absence of defects. 13,14 However, this process requires template generation on the same length scale as the period of the block copolymer. 15 On the other hand, well-ordered arrays of inplane cylinders templated by larger scale topographic patterns have been demonstrated by several groups.…”

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.…”