Design, synthesis, and application of block copolymers containing gradient random block

Abstract

Directed self-assembly of block copolymers has been considered as one of the possible candi-dates for the sub-10 nm scale advanced lithography technology. However, relatively high de-fect density due to the bottom-up process, and complicated technology in order to form vertical lamellar structure has been considered as obstacles to apply this to various lithographic applica-tions. In Part 1, solvent vapor annealing was applied to directed self-assembly process in order to improve pattern defect density. In Part 2, we propose new block copolymer system, block copolymer containing gradient random block, which has extreme thermodynamic preference to form vertical lamellar structures even without topcoat nor neutral brush layer, which is widely used technology forming sub-10 nm line/space pattern. This block copolymer system was thermodynamically designed and synthesized, so that it could form vertical lamellar structures on various chemically modified substrates. Furthermore, in Part 3, the synthesized block copol-ymers formed hybrid structure with extreme ultraviolet single exposure substrate. Using the ex-perience obtained in Part 1, defect density is carefully controlled by changing annealing tem-perature and guide pattern pitch, so that pattern defect density less than 1 μm-2 was obtained. Finally, the hybrid pattern was pattern-transferred to silicone substrate using the block copoly-mers as an etching mask.