Recent work in Russell group
· Microphase separation controlled by hydrolysis reaction in solid state
· Lamellar morphology with sub-10 nm full pitch obtained in bulk and thin films
Semiconductor device fabrication has been developing rapidly in recent years. It’s been harder to keep up with Moore's law since top-down photolithography is approaching the diffraction limit. Self-assembly of block copolymers has been proved to be a promising solution for its highly reproducible self-assembly, great diversity of morphology, good etching contrast, economic efficiency and recipes compatible for industrialization. Well aligned self-assembled patterns with sub-10 nm feature size and good etching contrast in thin films have been achieved in recent years. However, poor solubility, unfavored orientation of lamellas and high energy barrier for defect annihilation remain to distant block copolymers from its applications. We hereby developed a series of linear block copolymers and bottlebrush block copolymers containing ketal groups as side chains for low-χ to high-χ conversion in solid state. Self-assembled lamellar and cylindrical morphology with minimum 5.4 nm full pitch was obtained in bulk and 9.4 nm full pitch in thin films, which is among the smallest domains obtained so far.