Directed Self-Assembly of Silicon-Containing Block Copolymer Thin Films

The directed self-assembly (DSA) of lamella-forming poly­(styrene-block-trimethylsilylstyrene) (PS–PTMSS, L 0 = 22 nm) was achieved using a combination of tailored top interfaces and lithographically defined patterned substrates. Chemo- and grapho-epitaxy, using hydrogen silsesquioxane (HSQ) based prepatterns, achieved density multiplications up to 6× and trench space subdivisions up to 7×, respectively. These results establish the compatibility of DSA techniques with a high etch contrast, Si-containing BCP that requires a top coat neutral layer to enable orientation.