Three Dimensional Structures from the Directed Self-Assembly of Block Copolymers

Well-ordered block copolymer patterns offer compelling opportunities in nanofabrication and nanolithography. The utility of directed self assembly (DSA) can be enhanced by expanding the range of possible microdomain geometries available via complex polymer architectures, and by developing methods to control self-assembly in the out-of-plane direction to make three dimensional structures. We will demonstrate the formation of crosspoint, T-shaped and ladder-shaped structures in cylindrical morphology block copolymers templated in trenches, including a method to reversibly lock and unlock the microdomain morphology using metal infiltration. We then describe Janus bottlebrush triblock terpolymers that form hierarchical structures with two independently tunable periods, such as a mesh, cylinder or lamellar substructure within a lamellar superstructure. DSA yields templated patterns within and perpendicular to the plane. Combinations of novel polymers, templating approaches, and processing techniques yield an extensive array of rectilinear and 3D pattern geometries that can expand current nanofabrication capabilities.