A Universal Approach to Fabricating 3D Chemical Patterns for Directed Self-Assembly of Block Copolymers with Density Multiplication
Guangcheng Huang, Hanwen Lai, Jun Song, Yi-Zhou Jiang, Shengxiang Ji
Abstract
Directed self-assembly (DSA) of block copolymers (BCPs) with density multiplication has been proved to be a viable technique for the fabrication of FinFET at the 7 nm node. The key to the realization of DSA with density multiplication is to control the interfacial energy between BCP and the underlying substrate. In this work, we report a universal and fab-compatible approach to fabricating 3D chemical patterns for DSA of BCPs with density multiplication by combining lithographic patterning and plasma treatment. The surface energy of cross-linked polystyrene (XPS) mat could be tuned for controlling the wetting behavior of BCP films by simply adjusting oxygen plasma treatment conditions. Non-preferential surfaces for poly (styrene- b -methyl methacrylate) (PS- b -PMMA), poly (styrene- b -methyl acrylate) (PS- b -PMA), poly (styrene- b -propylene carbonate) (PS- b -PPC), and poly (styrene- b -(lactic acid-alt-glycolic acid)) (PS- b -PGLA) are obtained by oxygen plasma treatment, which eliminates the use of random copolymer brushes in the LiNe flow. 3D chemical patterns are successfully fabricated by combining e-Beam patterning of PMMA photoresist and oxygen plasma treatment, and DSA of lamellae-forming PS- b -PMMA and PS- b -PMA with up to 10x density multiplication is achieved on 3D chemical patterns.