Morphology Control in Block Copolymer Films Using Mixed Solvent Vapors

TitleMorphology Control in Block Copolymer Films Using Mixed Solvent Vapors
Publication TypeJournal Article
Year of Publication2012
AuthorsGotrik, KW, Hannon, AF, Son, JGon, Keller, B, Alexander-Katz, A, Ross, CA
JournalAcs Nano
Pagination8052 - 8059
Date Published2012/09//

Solvent vapor annealing of block copolymer thin films can produce a range of morphologies different from the equilibrium bulk morphology. By systematically varying the flow rate of two different solvent vapors (toluene and n-heptane) and an inert gas, phase maps showing the morphology versus vapor pressure of the solvents were constructed for 45 kg/mol polystyrene-block-polydimethylsiloxane diblock copolymer films of different thicknesses. The final morphology was correlated with the swelling of the block copolymer and homopolymer films and the solvent vapor annealing conditions. Self-consistent field theory is used to model the effects of solvent swelling. These results provide a framework for predicting the range of morphologies available under different solvent vapor conditions, which is important in lithographic applications where precise control of morphology and critical dimensions are essential.