Abstract
The self-assembly of a lamellar-forming polystyrene-
-poly(dimethylsiloxane) (PS-
-PDMS) diblock copolymer (DBCP) was studied herein for surface nanopatterning. The DBCP was synthesized by sequential living anionic polymerization of styrene and hexamethylcyclotrisiloxane (D₃). The number average molecular weight (
), polydispersity index (
/
) and PS volume fraction (φ
) of the DBCP were
= 23.0 kg mol
,
= 15.0 kg mol
,
/
= 1.06 and φ
= 0.6. Thin films of the DBCP were cast and solvent annealed on topographically patterned polyhedral oligomeric silsesquioxane (POSS) substrates. The lamellae repeat distance or pitch (λ
) and the width of the PDMS features (
) are ~35 nm and ~17 nm, respectively, as determined by SEM. The chemistry of the POSS substrates was tuned, and the effects on the self-assembly of the DBCP noted. The PDMS nanopatterns were used as etching mask in order to transfer the DBCP pattern to underlying silicon substrate by a complex plasma etch process yielding sub-15 nm silicon features.