| 초록 |
Directed self-assembly (DSA) of block copolymers (BCPs) has attracted much attention due to the potential for fabricating next-generation microelectronic devices. Silicon-containing BCPs with high interaction parameters (χ) have been used to create line-and-space patterns with critical dimensions as small as 5 nm. However, there are still challenges in pattern defect reduction. A hybrid chemo-/grapho-epitaxial alignment strategy is an effective strategy that was developed to reduce the defect density. It was hypothesized that the DSA could be achieved only with the interaction of a polar block of a BCP with a polar sidewall of guidelines. The challenge was to increase the polarity of the sidewall while rendering the SiO2 substrate neutral to the BCP. This work shows how polymer brushes can be developed to have the grafting selectivity that is required to control surface energies at the bottom interfaces. It was found that hydroxyl-terminated brushes graft selectively on the SiO2, while amine-terminated brushes selectively graft on the sidewalls. Sequential grafting of these brushes resulted in the neutral SiO2 substrate and polar sidewalls necessary to achieve the hybrid DSA. |
