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

• Published in: Nature nanotechnology Vol. 5; no. 4; pp. 256 - 260
• Main Authors: Ross, C. A, Yang, Joel K. W, Mickiewicz, R. A, Chang, Jae-Byum, Jung, Yeon Sik, Berggren, Karl K, Alexander-Katz, A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.04.2010; Nature Publishing Group
• Subjects: 639/638/455; 639/925/357/341; 639/925/930/543; Arrays; Chemistry and Materials Science; Computer engineering; letter; Materials Science; Morphology; Nanotechnology; Nanotechnology and Microengineering; Polymers; Silicon wafers; Thin films; United States > US; Massachusetts
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/nnano.2010.30

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. 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. Suitable distributions of vertical posts, prepared by electron-beam patterning of an inorganic resist, can be used to template complex patterns in a cylindrical block copolymer.