Directed self-assembly of block copolymers by chemical or topographical guiding patterns: Optimizing molecular architecture, thin-film properties, and kinetics

Patterning strategies based on directed self-assembly (DSA) of block copolymers, as one of the most appealing next-generation lithography techniques, have attracted abiding interest. DSA aims at fabricating defect-free geometrically simple patterns on large scales or irregular device-oriented structures. Successful application of DSA requires to control and optimize multiple process parameters related to the bulk morphology of the block copolymer, its interaction with the chemical or topographical guiding pattern, and the kinetics of structure formation. Most studies have focused on validating DSA patterning techniques using PS-b-PMMA block copolymers as a prototypical material. As the development of DSA techniques advances, recent efforts have been devoted to extending the materials selection in order to fabricate more complex geometric patterns or patterns with smaller characteristic dimensions. How to select appropriate polymer materials in a vast parameter space is a critical but also challenging step. In this review, we discuss recent progress in the research of DSA of block copolymers focusing on three aspects: (i) screening the block copolymer materials, (ii) controlling the film properties, and (iii) tailoring the phase separation kinetics.