Block copolymer thin film ordering

This review will discuss two types of patterning approaches that can be employed with patternable block copolymers. Due to the fact that most practical applications require block copolymer thin films with large-domain ordered patterns, particular attention is paid to the optimization of bottom-... 

In addition to the previously mentioned driving forces that determine the bulk state phase behavior of block copolymers, two additional factors play a role in block copolymer thin films the surface/interface energies as well as the interplay between the film thickness t and the natural period, Lo, of the bulk microphase-separated structures [14,41,42], Due to these two additional factors, a very sophisticated picture has emerged from the various theoretical and experimental efforts that have been made in order to describe... 

Olszowka V, Kuntermann V, Boker A (2008) Control of orientational order in block copolymer thin films by electric fields a combinatorial approach. Macromolecules 41 5515-5518... 

Chen A, Komura M, Kamata K, lyoda T. 2008. Highly ordered arrays ofmesoporous silica nanorods with tunable aspect ratios from block copolymer thin films. Adv Mater 20 763 767. 

Xu, T., Goldbach, J.T., Russell, T.P. Sequential, orthograial fields a path to long-range, 3-D order in block copolymer thin films. Macromolecules 36, 7296 (2003)... 

Virgin, J.M., Tao, Y., Kortright, J.B., Balsara, N.P., Segalman, R.A. Analysis of order formation in block copolymer thin films using resonant soft x-ray scattering. Macromolecules 40, 2092 (2007)... 

Kim, S., Nealey, P.E., Bates, E.S. Directed assembly of lamellae forming block copolymer thin films near the order-disorder transition. Nano Lett. 14, 148 (2014)... 

Because of the various technological applications of polymer thin films, ranging from multicolor photographic printing to flat panel and liquid crystal displays, it is important to understand thin film and polymer surface characteristics in order to improve performance or to develop entirely new applications or processing methodologies. Polymer and block copolymer thin films and surfaces thus enjoy continued research interest from both a technological and fimdamental perspective. 

Directed self-assembly shows promise in advanced lithography and a variety of other applications that have less complex requirements. For example, directed self-assembly could be used for enhancing etch selectivity, placing dopants in ordered arrays, or generating high-density, close-packed electrodes in capacitor arrays [6]. Additionally, the assembled nanostructures could be used for fabricating densely packed porous templates [12-14] or membranes [15, 16] at the nanoscale. Other potential applications of assembled block copolymer thin films include the fabrication of MOSFETs (metal-oxide-semiconductor field-effect transistors) [17], quantum dots [18], high surface area devices [19, 20], photovoltaic devices [21], and bit patterned media [22-24]. 

Park, S., Kim, B. etal. (2008) Fabrication of highly ordered siUcon oxide dots and stripes from block copolymer thin films. Advanced Materials, 20(4), 681-685. 

Segahnan, R.A., Hexemer, A. et al. (2003a) Effects of lateral confinement on order in spherical domain block copolymer thin films. Macromolecules, 36(18), 6831-6839. 

Palchoudhury S, An W, Xu Y, Qin Y, Zhang Z, Chopra N, Holler RA, Turner CH, Yu B (2011) Synthesis and growth meehanisni of iron oxide nanowhiskers. Nano Lett 11(3) 1141-1146 Park SH, Kim BJ, Hawko- CJ, Kramer EJ, Bang J, Ha JS (2007) Controlled ordering of block copolymer thin films by the addititm of hydrophilic nanoparticles. Macromolecules... 

Table 1 Summary of block copolymers studied in order to control microdomain orienta-tions in thin film states ...

Martinelli, E. Galli, G. Krishnan, S. Paik, M. Y. Ober, C. K. Fischer, D. A., New Poly (dimethylsiloxane)/Poly(perflurooctyl acrylate) Block Copolymers Structure and Order Across Multiple Length Scales in Thin films. J. Mater. Chem. 2011,21,15357-15368. 

Figure 5 (a) M-plane sapphire, (b) Sawtooth patterns from the facets of sapphire after thermal treatment, (c) Deposition of thin films of block copolymer, (d) Highly ordered cylindrical microdomains oriented normal to the surface after solvent vapor annealing, (e and f) Atomic force microscopy (AFM) images of the block copolymer surface with thickness of (e) 24 nm and (f) 34 nm on a surface with facets having pitches of 130 and lOOnm with amplitudes of 14 and lOnm. Scale bars. 200nm. 

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