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Download as PDFTemplated Self-assembly of Block Copolymers for Nanolithography
Self-organized macromolecular materials can provide an alternative pathway to conventional lithography for the fabrication of devices on the nanometer scale. In particular, the self-assembly of the microdomains of diblock copolymers within lithographically-defined templates to create patterns with long range order has attracted considerable attention, with the advantages of cost-effectiveness, large-area coverage, and compatibility with preestablished top-down patterning technologies. Previously, we showed that spherical morphology poly(styrene-b-dimethylsiloxane) (PS-PDMS) block copolymers, which have a large interaction parameter and a high etch-contrast between two blocks, can be templated using an array of nanoscale topographical elements that act as surrogates for the minority domains of the block copolymer [1] . Recently, we showed that complex nanoscale patterns can be generated by combining the self-assembly of block-copolymer thin films with minimal top-down templating. A sparse array of nanoscale HSQ posts was used to accurately dictate the assembly of a cylindrical PS-PDMS diblock copolymer into a wide assortment of complex, unsymmetrical features, as shown in Figure 1 [2] . To extend the feature sizes to the sub-10-nm range, we demonstrated the formation of highly ordered grating patterns with a line width of 8 nm and period of 17 nm from a self-assembled PS-PDMS diblock copolymer and fabricated sub-10-nm-wide tungsten nanowires from the self-assembled patterns using a reactive ion etching process, as shown in Figure 2.
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- Figure 1: SEM images of highly organized and asymmetric complex cylindrical BCP patterns with an array of HSQ posts (brighter dots) prepared by electron-beam patterning. (a) zig-zag pattern and (b) meander structure with sharp bends.
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- Figure 2: Sub-10-nm-wide PDMS pattern and their pattern transfer to sub-10 nm tungsten nanowires.
- I. Bita, J. K. W. Yang, Y. S. Jung, C. A. Ross, E. L. Thomas, and K. K. Berggren, “Graphoepitaxy of self-assembled block copolymers on two-dimensional periodic patterned templates,” Science, vol. 321, pp. 939-943, 2008. [↩]
- J. K. W. Yang, Y. S. Jung, J.-B. Chang, C. A. Ross, and K. K. Berggren, “Complex self-assembled patterns using sparse commensurate templates with locally varying motifs,” Nature Nanotechnology, vol. 5, pp. 256-260, 2010. [↩]