Block copolymer (BCP) microphase separation at substrate
surfaces might enable the generation of substrate features in a scalable, bottom-up
fashion, provided that the pattern structure, orientation, and alignment can be
strictly controlled. The PS-b-PDMS (polystyrene-b-polydimethylsiloxane) system
is attractive because it can form small features and the two blocks can be
readily differentiated during pattern transfer. However, PS-b-PDMS offers a
considerable challenge, because of the chemical differences in the blocks,
which leads to poor surface wetting, poor pattern orientation control, and structural
instabilities. These challenges are considerably greater when line patterns
must be created, and this is the focus of the current work. Here, we report
controlled pattern formation in cylinder-forming PS-b-PDMS by anchoring different
types of hydroxyl-terminated homopolymer and random copolymer brushes on planar
and topographically patterned silicon substrates for the fabrication of
nanoscale templates. It is demonstrated that non-PDMS−OH-containing brushes may be
used, which offers an advantage for substrate feature formation. To demonstrate
the three-dimensional (3-D) film structure and show the potential of this system
toward applications such as structure generation, the PDMS patterns were
transferred to the underlying substrate to fabricate nanoscale features with a feature
size of ∼14 nm.