  In a hierarchical nanopatterning routine relying exclusively on self-assembly
processes we combine crystal surface reconstruction, microphase separation of
copolymers, and selective metal diffusion to produce monodisperse metal
nanostructures in highly regular arrays covering areas of square centimeters.
In-situ GISAXS during Fe nanostructure formation evidences the outstanding
structural order in the self-assembling system and hints at possibilities of
sculpting nanostructures by external process parameters. Thus, we demonstrate
that nanopatterning via self-assembly is a competitive alternative to
lithography-based routines, achieving comparable pattern regularity, feature
size, and patterned areas with considerably reduced effort. The option for
in-situ investigations during pattern formation, the possibility of customizing
the nanostructure morphology, the capacity to pattern arbitrarily large areas
with ultra-high structure densities, and the potential of addressing the
nanostructures individually enable numerous applications, e.g., in high-density
magnetic data storage, in functional nanostructured materials, e.g., for
photonics or catalysis, or in sensing based on surface plasmon resonances.
