Double textured cylindrical block copolymer domains via directional solidification on a topographically patterned substrate

Directional solidification of cylinder forming block copolymer films confin ed between a directionally crystallizing solvent (benzoic acid) and a topog raphically patterned silicon substrate imparts a particular orientation to the block copolymer microdomains that is dependent of the solidification di rection and the local film thickness. The substrate features (30 nm high, 2 mum wide square mesas on a 4 mum sq lattice) shape the film morphology by periodically modulating the local film thickness. Thicker regions between s ubstrate features (plateaus) exhibit in-plane cylinders aligned in the crys tallization direction and thinner regions over the substrate features (mesa s) display vertically aligned cylindrical domains. This approach is a simpl e and general technique for engineering an intended domain orientation in s pecific areas of a block copolymer film. Development of this method for nan olithographic applications is demonstrated through oxygen plasma reactive i on etching of the patterned cylindrical domains. (C) 2001 American Institut e of Physics.