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Block copolymers (BCPs) have the potential to play a key role in templating materials for nanoscale synthesis. BCP lithography likely will be one of the first examples of BCP-based nanomanufacturing implemented in a production setting. One of the challenges in implementing BCP lithography is that the lamella need to be oriented perpendicular to the substrate. For many systems, this requires control over interfacial energies for both components at the substrate and interface. Top coats can be designed to provide a neutral interface for both blocks on the BCP surface. The preferentiality of the top coat as a function of composition has been determined qualitatively by examining the orientation of a BCP after annealing with a top coat. Measurements of the interfacial width between the top coat and homopolymers allows the interface energy to be quantitatively determined. Resonant soft X-ray reflectivity measurements on top coat/homopolymer pairs were used to extract the Flory-Huggins parameter (χ) and interface energy (γ) as a function of top coat composition. The difference between χ and γ for each top coat/homopolymer pair was minimized at compositions that resulted in the top coat promoting perpendicular orientation. As the composition moved away from the neutral point the difference between χ and γ for each pair grew larger.

The depth-dependent structure of a poly(styrene- b -methylmethacrylate) (PS-PMMA) line grating (46 nm pitch) was calculated from quantitative analysis of small-angle X-ray scattering profiles. These data demonstrate that domain shapes are significantly deformed near the substrate interface, where the local PS domain shape resembles an hourglass. The bulk equilibrium dimension is recovered near the center of a 64 nm thick film. Simulations based on self-consistent field theory suggest that deformations near the substrate are caused by extensive penetration of the copolymer domains into the underlying substrate coating (a PS-brush). These findings suggest that new coatings for block copolymer directed self-assembly should consider copolymer penetration lengths in addition to tailoring surface energetics. Furthermore, given the resolution and ensemble-averaging features of synchrotron X-ray scattering, we argue that it has the potential to emerge as a "gold-standard" or "benchmark" dimensional metrology and library validation tool for high density, sub-10 nm features.