Hemicellulose Block Copolymers for Advanced Lithography Process

Directed self-assembly (DSA) lithography is one of the promising next-generation lithography technologies. However, there are two main limitations to the use of DSA. One is the narrowness of the pattern size window and the other is the fabrication of the underlayer. To address the former limitation, wide-range DSA has been applied to expand the applicable patterning size while the latter has been achieved by utilizing the newly developed reactive hemicellulose hardening (R2H) technique. In R2H, the hemicellulose unit is selectively hardened by a chemical reaction. In this study, hemicellulose block copolymers for wide-range DSA lithography and its fabrication technology were newly developed. A hemicellulose high-chi block copolymer (OPAL-BCP) and its underlayer were fabricated using R2H. After reactive ion etching of the underlayer with R2H, a pattern depth of over 300 nm and etching selectivity of 24 were obtained.