Block copolymer (BCP) microphase separation
at surfaces might enable the generation of substrate features in
a scalable, manufacturable, bottom-up fashion provided that
pattern structure, orientation, alignment can be strictly controlled.
A further requirement is that self-assembly takes place within periods of the order of minutes so that continuous manufacturing
processes do not require lengthy pretreatments and sample storage
leading to contamination and large facility costs. We report here microwave-assisted solvothermal (in toluene environments)
self-assembly and directed self-assembly of a very low molecular
weight cylinder-forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS) BCP on planar and patterned silicon nitride (Si3N4) substrates. Good pattern ordering was achieved in the order of minutes. Factors affecting BCP self-assembly,notably anneal time and temperature were studied and seen to have significant effects. Graphoepitaxy to direct self-assembly in the BCP yielded promising results producing BCP patterns with long-range translational alignment commensurate with the pitch
period of the topographic patterns. This rapid BCP ordering method is consistent with the standard thermal/solvent anneal
processes.