Reworkable dimethacrylates with low shrinkage and their application to UV nanoimprint lithography

Four types of reworkable dimethacrylates bearing hemiacetal ester groups were synthesized and the UV curing and degradation were studied. UV nanoimprint lithography (UV-NIL) using these monomers was performed and fine line/space patterns were obtained. The shrinkage in height of the UV imprinted pattern was studied in relation to the monomer structure and UV imprint conditions such as light intensity and concentrations of photoradical initiator and chain transfer reagent. The effect of UV imprint conditions on the kinetic chain length of UV cured networks was investigated using size exclusion chromatography of the linear polymers obtained from the degradation of the UV imprinted patterns. A relationship between the kinetic chain length and shrinkage of the UV imprinted patterns was discussed.