Reduction of pattern peeling in step-and-flash imprint lithography

A strong adhesion force between resist and underlayer materials was employed to reduce resist pattern peeling generated from de-molding in step-and-flash imprint lithography (SFIL), while simultaneously minimizing the adhesion force between resist material and the template surface with fluorinated surfactants. The reduction in resist pattern peeling by the interaction between the fluorinated SiO2 resist with epoxy groups and UV reactive underlayer materials with epoxy groups during UV irradiation was investigated. An optimized resist material formulation and high adhesion strength between resist and underlayer materials led to the well-patterned 80 nm resist lines on an underlayer for 100 imprints. The underlayer material was modified by a thermal crosslinking reaction of the aminoplast at 130 °C before nanoimprinting and, in conjunction with a cationic epoxy chemical reaction between the resist and the underlayer during UV irradiation before de-molding, proved to be quite effective for SFIL defect reduction.