Study of fluorinated silicon-based resist material and photoreactive underlayer for defect reduction in step and repeat ultraviolet nanoimprint lithography

Step and repeat ultraviolet (UV) nanoimprint lithography has advantages such as metal-direct patterning, develop-less process, low line-edge-roughness and easy operation. However, the dirty-template-causing resist pattern peeling and the defect present challenges that must be resolved for mass-produce nano-devices. The approach to use the chemical adhesion by cationic polymerisation between resist material and the photoreactive underlayer during UV irradiation was investigated as the next generation of clean separation technology between template and resist material in step and repeat UV nanoimprint lithography. The obtained chemical adhesion between epoxy groups of the new fluorinated sol-gel silicon-based resist polymer and epoxy groups of novolac-type photoreactive underlayer was achieved with excellent 80-nm patterning dimensional accuracy by replication of imprint process cycles over 32 times, and was one of the key to reduce the resist pattern peeling and defect numbers.