Topographically directed self-assembly

Figure 1 Schematic illustration of the two major approaches of directed self-assembly of block copolymers, (a) Graphoepitaxy the self-assembly of block copolymers is guided by topography and possibly also surface chemistry, (b) Chemical epitaxy spatial variation of surface chemistry directs the self-assembly of block copolymers. In both cases, the hard mask or pinning region has high affinity to A domains, while neutral surface provides vertically oriented A and B domains. Such affinity drives the self-alignment of polymer domains to the topographical and chemical patterns.

Fig. 14 Graphoepitaxy vs epitaxial self-assembly, (a) Graphoepitaxy utilizes topographic substrate pattern for directed block copolymer assembly. The substrate pattern remains in the finally formed nanopattemed morphology, (b) Epitaxial self-assembly utilizes nanoscale chemical pattern to register block copolymer assembly. Ultrafine chemical patterning requires e-beam lithography or other high-cost lithography such as EUV. Reprinted with permission from Jeong et al. [153]. Copyright 2010 American Chemical Society...

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