High-χ block copolymers are attractive for lithography due to their ability to self-assemble in the sub-10 nm regime. Unfortunately, surface energy minutiae often hinder the formation of useful orientations. For lithographic applications, this is particularly important, as orientation must be reproducible and defect-free across the entirety of the substrate. To facilitate the orientation process, an algebraic model has been developed to predict orientation conditions that confer perpendicular and parallel lamellar orientation. This model compares the free energy of perpendicular lamellae versus that of parallel lamellae at different film thicknesses with different top and bottom interfaces. Preliminary results show that with one neutral interface, the thickness window favoring vertical orientation shrinks as the other interface becomes more preferential. Furthermore, several unique circumstances exist when both interfaces are equally preferential toward the block copolymer, with the model predicting a wide processing window in which perpendicular orientation is preferred. Additionally, the thicknesses that can produce perpendicular orientation vary wildly depending on the preferences of the top and bottom interfaces. To test the validity of the model, rigorous experimental orientation studies were performed. These experiments largely corroborated the model’s predictions. The results of this study will prove valuable for understanding thin film orientation control and for selecting processing conditions for block copolymer directed self-assembly.

Modeling of block copolymer thin film behavior between neutral and preferential interfaces

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.