Complex self-assembled patterns using sparse commensurate templates with locally varying motifs

Abstract

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. However, arbitrary pattern generation directed by sparse templates remains elusive. Here, we show that an array of carefully spaced and shaped posts, prepared by electron-beam patterning of an inorganic resist, can be used to template complex patterns in a cylindrical-morphology block copolymer. We use two distinct methods: making the post spacing commensurate with the equilibrium periodicity of the polymer, which controls the orientation of the linear features, and making local changes to the shape or distribution of the posts, which direct the formation of bends, junctions and other aperiodic features in specific locations. The first of these methods permits linear patterns to be directed by a sparse template that occupies only a few percent of the area of the final self-assembled pattern, while the second method can be used to selectively and locally template complex linear patterns.

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.…”

Design rules for self-assembled block copolymer patterns using tiled templates

“…When directed by a sparse topographic or chemical template, the block copolymers self-assemble into long-range ordered patterns with a controlled orientation [9][10][11][12][13][14][15][16][17] . These aligned patterns have been used as lithographic masks to fabricate devices including patterned magnetic recording media, flash memory and nanowire or graphene ribbon transistors [18][19][20][21][22][23][24][25] .…”

Enabling complex nanoscale pattern customization using directed self-assembly

“…The directed self-assembly (DSA) of BCP thin films using chemical [3][4][5][6][7][8] or topographical [9][10][11][12][13][14][15][16] templates to impose long-range order and registration on the BCP domains has garnered increased interest in recent years as a means to enhance lithographic resolution by multiplying the feature density [5][6][7][8][13][14][15] and rectifying pattern non-uniformity or imperfections 5,6,17,18 of lithographically defined templates. Selective removal or alteration of one block then creates a mask that may be combined with other manufacturing techniques to fabricate devices such as patterned magnetic recording media 19 , silicon nanowire transistors 20 or FinFETs 21 .…”

“…This strategy has been demonstrated previously using one-to-one 4,24 or two-to-one 25 chemical pattern templates. Complex self-assembled patterns may also be created using sparse topographical templates of post arrays with locally modified spacings, shapes or orientations to adjust the preferred commensurability conditions controlling lateral alignment of BCP domains 14,15 , which can be designed using configurable square post lattice template tiles 26 . Even so, the range of possible customizations is restricted, and achieving high target pattern yields is challenging.…”