Inorganic block copolymer lithography

Block copolymer lithography, a process where block copolymer self-assembly is integrated with conventional lithographic patterning, is emerging as a promising technology for addressing the future needs of the semiconductor industry. The ability of block copolymers to self-assemble into ordered nanodomains allows for simple, low cost nanopatterning into underlying substrates. Since its initial conception, block copolymer lithography has been demonstrated using a variety of block copolymers, with research primarily focusing on all-organic diblock copolymers. The most notable example is polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) where long-range ordering of nanodomains has allowed applications on a commercial scale. However, scaling down of the feature sizes produced from the self-assembly of organic block copolymers is often limited due to the relatively low Flory-Huggins interaction parameter, χ. In addition, etch selectivity between the blocks, and their etch resistance for subsequent pattern transfers steps, is generally low. This review article provides an overview of how the introduction of segments containing inorganic elements into block copolymers can help to address these issues and can also allow the direct deposition of functional materials such as metal nanoparticles. This has led to potential interest for the next generation of block copolymer lithography applications.