Directed self-assembly of 3D interconnected networks

Directed self-assembly (DSA) of block copolymers (BCPs) has long been included in the semiconductor roadmap as a lithographic pathway to enable continued device scaling. Tremendous progress has been made in generating two-dimensional (2D) BCP patterns with device-relevant features and low defect density and in transferring these patterns to functional materials. Extension of pattern generation into 3D could markedly enhance the utility of BCPs in nanoscale manufacturing, but methods to template and synthesize well-ordered, nontrivial 3D structures are less well developed. Here, we demonstrate a hierarchical DSA method to generate cross-point structures with connected in-plane and out-of-plane segments and controlled orientation angle between the horizontal layers. Various highly ordered, 3D interconnected networks, including ladder and cross-point structures, are produced by combinations of surface modification, BCP periodicity, and topographic templates, expanding the capabilities of BCP-derived nanofabrication.