Directed Assembly of Lamellae Forming Block Copolymer Thin Films near the Order–Disorder Transition

Abstract

The impact of thin film confinement on the ordering of lamellae was investigated using symmetric poly(styrene-b-[isoprene-ran-epoxyisoprene]) diblock copolymers bound by nonpreferential wetting interfaces. The order-disorder transition temperature (TODT) and the occurrence of composition fluctuations in the disordered state are not significantly affected by two-dimensional confinement. Directed self-assembly using chemical patterning is demonstrated near TODT. These results establish the minimum feature size attainable using directed self-assembly of a given diblock copolymer system.

Order–disorder transition in thin films of horizontally-oriented cylinder-forming block copolymers: thermal fluctuations vs. preferential wetting

“…[37][38][39] In these studies, they observed that the T ODT suppression for the lamellar morphologies is anticipated only when 5 the film thickness becomes comparable to (or smaller than) the radius of gyration (R g ). The scope of the preliminary ODT investigations that incorporated thermal fluctuations have been limited previously to thin films of a lamellar morphology bound by non-preferential interfaces.…”

Block Copolymers for DSA in the 100 ^|^Aring; Regime

“…If the top coat and the bottom coat are perfectly neutral, the perpendicular orientation of lamellae is independent of thickness [21,22]. There are examples of block co-polymers that form high-resolution structures that do not require a top coat [23] for processing, but the authors know of no silicon containing block copolymers that can be oriented by thermal annealing without a top coat.…”

Nanopatterns Produced by Directed Self-Assembly in Block Copolymer Thin Films

“…Search for ever-smaller characteristic sizes, in order to reach the sub-20 nm limits desired for lithography applications, has involved the choices of new monomer combinations [13,113], salt complexation [114], and exploration of the weak segregation regime [115]. However, this goal is conflicting with the need for defectfree patterns, since the energy cost of a defect formation typically scales as the third power of the nanostructure characteristic size [116].…”